Antimicrobial Efficacy of a Portable UV-C-Based Coating Activation Device against Candida albicans Biofilm and SARS-CoV-2 as an Additional Feature: An In Vitro Study.


Mouth breathing reduces oral function in adolescence


Social frailty as a predictor of all-cause mortality and functional disability: a systematic review and meta-analysis


Association between working in small-scale cultivated land as a daily-life task and the physical and cognitive functions among elderly people in hilly and mountainous areas

中山間地域に居住する高齢者の生活行為としての畑作業と身体・認知機能との関連


Effective use of an extraoral vacuum in preventing the dispersal of particulate matter from metal dental materials.

When dentists adjust prostheses at the dental chairside, particulate matter (PM) from the dental material is dispersed. Little is known about the effective use of an extraoral vacuum (EOV) in preventing PM dispersal. This study aimed to evaluate the effective use of an EOV in preventing the dispersal of metal PM in dental offices. The following experimental conditions were planned: the distance from the EOV to the metallic materials (50, 100, 150, and 200 mm), the horizontal angle between the long axis of the micromotor handpiece and EOV (0°, 45°, and 90°), and the operating time of the EOV (during grinding, during grinding and 1 min thereafter, during grinding and the preceding 1 min, 1 min before and after grinding, and during grinding). Carborundum and silicone points were used for grinding and PM dispersal. Diameters (0.3, 0.5, 1.0, and 3.0 μm) were measured using a laser particle counter. Depending on the instrument used to grind, there were undetectable PMs of different diameters (Carborundum point: 0.3 and 0.5 μm, Silicone point: 0.3 μm). PMNs were reduced as the distance from the EOV to metal materials decreased. Operating the EOV before grinding along the long axis of the micromotor handpiece was effective in reducing the PMNs. PMNs dispersed when grinding metals were effectively reduced by positioning the EOV closer to the grinding surface (within 150 mm) along the long axis of the micromotor handpiece and operating the EOV before grinding.


Effect of denture adhesives on masticatory performance: Multicenter randomized controlled trial.


補綴歯科はインプラント治療で何を見ているのか．

補綴歯科はインプラント治療で何を見ているのか．

日本顎顔面インプラント学会誌

日本顎顔面インプラント学会誌


Effect of Palatal Augmentation Prosthesis on Speech and Swallowing in Tongue Dysfunction:A Literature Review

Purpose: Palatal augmentation prosthesis (PAP) is used on patients with dysphagia and dysarthria. While several studies have evaluated the effects of PAP, evidence regarding the adaptation criteria, effects, and limitations of PAP are not well organized. This review aims to summarize its functions, limitations, and applications. Procedure: To investigate the adaptation criteria, effects, and limitations of PAP, we searched the English language literature published in PubMed from its inception through April 20, 2022. The leading search terms included ``palatal augmentation prosthesis.'' Main findings: The primary search used keywords that reflected 31 studies. Finally, nine cross-sectional studies and nine case reports were selected for full-text assessment after applying the inclusion criteria. Eleven studies described the efficacy of speech function: two for motility factors and nine for organic factors (with overlap). Thirteen studies described the effectiveness of swallowing function, four related to motility factors, and ten for organic factors (with overlap). Several studies have demonstrated that PAP effectively restores articulation and swallowing in patients with impaired tongue function after glossectomy for oropharyngeal cancer, sequelae of cranial nerve disease, or neuromuscular disease. However, few papers describe the scope of glossectomy and tongue movement restrictions, so it is impossible to describe the adaptation criteria, effects, and limitations. In this review, most case reports and cross-sectional studies did not provide information on the fabrication methods of PAP or the dentistsʼ experience. Thus, the effect of bias on palatal morphology in PAP patients remains unclear. Conclusions: The number of patients with dysarthria and dysphagia is increasing worldwide, similar to what is already occurring in Japan. Therefore, additional high-quality studies on the effects of PAP are required.


Can Measurement of Ultrasonic Echo Intensity Predict Physical Frailty in Older Adults?

Echo intensity (EI) of the tongue in ultrasonography is an easy and quantitative assessment of tongue function. Elucidating the relationship between EI and frailty, is expected to aid in the early detection of frailty and oral hypofunction in older adults. We assessed tongue function and frailty in older outpatients visiting a hospital. The subjects were 101 individuals aged 65 or older (35 men and 66 women, mean age 76.4 ± 7.0 years). Tongue pressure and EI were measured as assessments of tongue function and grip strength, and Kihon Checklist (KCL) scores were measured as assessments of frailty. In women, a significant correlation was not found between the mean EI and grip strength, whereas a significant correlation was noted between each score of the KCL and the mean EI; the scores increased as the mean EI increased. A significant positive correlation was found between tongue pressure and grip strength, but no significant correlation was observed between tongue pressure and the KCL scores. In men, no significant correlation was found between tongue assessments and frailty, except for a significant positive correlation between tongue pressure and grip strength. The results of this study suggest that EI of the tongue is positively associated with physical frailty in women and may be useful for early detection of physical frailty status.


Effects of Candidalysin Derived from Candida albicans on the Expression of Pro-Inflammatory Mediators in Human Gingival Fibroblasts

International Journal of Molecular Sciences


Effects of denture adhesives on denture retention and occlusal forces in complete denture wearers: A multicenter, randomized controlled trial.

Application of cream-type denture adhesives effectively improves the denture retention and occlusal force in complete denture wearers with a moderate degree of difficulty during edentulism treatment.


Stress Reduction Effects during Block-Tapping Task of Jaw in Healthy Participants: Functional Near-Infrared Spectroscopy (fNIRS) Measurements of Prefrontal Cortex Activity

The purpose of this study was to explore the influence of simple jaw opening and closing task of chewing movements on the activities of the prefrontal cortex (PFC) from the viewpoint of stress reduction. We measured cerebral blood flow (CBF) in the PFC during a block-tapping task of the jaw in healthy participants. Eleven young healthy individuals with normal dentition (7 males and 4 females, mean age 28.0 ± 3.7 years) volunteered for this study. CBF was measured using a wearable, functional near-infrared spectroscopy device. Measurements were taken using the central incisors and first molars at interocclusal distances of 5 and 10 mm. The participants were asked to bite a hard/soft block. CBF in all conditions showed limited variability or decreasing trend compared to resting state before the task. The main effect was observed for interocclusal distance ( = 0.008), and there were no significant differences for measurement area of the PFC, tooth type, and material type. An interaction was found between tooth type and material type. In conclusion, these results suggest that simple and rhythmical chewing motion has an effect of reducing CBF in the PFC and resting the PFC, which is an especially notable aspect of periodontal sensory information in the molar.


歯科専門医認定制度の意義と一般社団法人日本歯科医学会連合における役割

歯科専門医認定制度の意義と一般社団法人日本歯科医学会連合における役割


青年期における姿勢と口腔機能との関連に関する実態調査

青年期における姿勢と口腔機能との関連に関する実態調査

The Journal of the Japanese Academy of Occulusion and Health


Impact of number of functional teeth on independence of Japanese older adults.

To examine the relationship between the number of present and functional teeth at baseline and future incidence of loss of independence. Participants were community-dwelling older individuals who participated in a comprehensive geriatric health examination conducted in Kusatsu town, Japan, between 2009 and 2015. The primary endpoint was the incidence of loss of independence among participants, defined as the first certification of long-term care insurance in Japan. The numbers of present and functional teeth at baseline were determined via an oral examination. Demographics, clinical variables (e.g., history of chronic diseases and psychosocial factors), blood nutritional markers, physical functions, and perceived masticatory function were assessed. This study included 1121 individuals, and 205 individuals suffered from loss of independence during the follow-up period. Kaplan-Meier estimates of loss of independence for participants with smaller numbers of present and functional teeth were significantly greater than for those with larger numbers of teeth. Cox proportional hazard analyses indicated that a smaller number of present teeth was not a significant risk factor after adjusting for demographic characteristics. However, the number of functional teeth was a significant risk factor after the adjustment (hazard ratio: 1.975 [1.168-3.340]). Additionally, higher hazard ratios were observed in other adjusted models, but they were not statistically significant. The number of functional teeth may be more closely related to the future incidence of loss of independence than the number of present teeth. This novel finding suggests that prosthodontic rehabilitation for tooth loss possibly prevents the future incidence of this life-event. Geriatr Gerontol Int 2022; 22: 1032-1039.


2-methacryloyloxyethyl phosphorylcholine polymer treatment prevents Candida albicans biofilm formation on acrylic resin

We aimed to evaluate the effectiveness of photoreactive 2-methacryloyloxyethyl phosphorylcholine (MPC) in inhibiting Candida albicans biofilm formation on polymethyl methacrylate (PMMA) and assess its mechanism and need for re-application by evaluating its interaction with salivary mucin and durability during temperature changes. PMMA discs were used as specimens. The MPC coating was applied using the spray and cure technique for the treatment groups, whereas no coating was applied to the control. The MPC treatment (MT) groups were further differentiated based on the number of thermal cycles involved (0, 1000, 2500, and 5000). The optical density was measured to assess mucin adsorption (MA). Contact angle (CA) was calculated to evaluate surface hydrophilicity. The presence of MPC components on the PMMA surface was assessed using X-ray photoelectron spectroscopy (XPS). C. albicans biofilms were evaluated qualitatively (scanning electron microscope images) and quantitatively (colony-forming units (CFUs)). Statistical analysis was conducted using two-way analysis of variance and Tukey's multiple comparison test. MA rate and CA increased significantly in the MT groups, which exhibited significantly fewer CFUs and thinner biofilms than those of the control group. Based on the XPS, MA, and CFU evaluations, the durability and efficacy of the MPC coating were considered stable up to 2500 thermal cycles. Additionally, a significant interaction was observed between mucin concentration and MPC efficacy. The photoreactive MPC coating, which was resistant to temperature changes for approximately 3 months, effectively prevented C. albicans biofilm formation by modifying surface hydrophilicity and increasing mucin adsorption.


Semaphorin 3A: A potential target for prevention and treatment of nickel allergy

Metal allergy is one of the typical immune disorders encountered during the application of dental/medical materials and has a highly complex pathogenic mechanism. Semaphorin 3A (Sema3A), a member of the semaphorin family, is reported to be involved in various immune disorders. However, its role in metal allergy has not been clarified yet. Herein, we show that Sema3A expression was upregulated in nickel (Ni) allergy-induced mouse ear tissue and in NiCl-stimulated mouse keratinocytes. Moreover, Sema3A regulated tumor necrosis factor-alpha production and mitogen-activated protein kinase activation in keratinocytes. The specific deletion of Sema3A in keratinocytes did not affect immune cell infiltration but reduced edema and ear swelling; it also impeded Th1 responses to cause a slight alleviation in Ni allergy in mice. Our results demonstrate that Sema3A promotes the development of metal allergy and should be explored as a potential target for the prevention and treatment of metal allergy.


Dendritic Cells Directly Recognize Nickel Ions as an Antigen during the Development


Novel Magnetic Attachment System Manufactured Using High-Frequency Heat Treatment and Stamp Technique: Introduction and Basic Performance

Recently, a novel magnetic attachment with extremely low cost and high performance was developed. This article aims to introduce a novel magnetic attachment and to evaluate its basic eligibility for denture retention in clinical practice. The novel magnetic attachment system used in this study was the direct-bonding root-keeper-type Magteeth™ MT800 (MagneDesign, Nagoya, Japan). The retentive force without displacement (position 0) and after horizontal displacement to positions 0.5, 1, 1.5, 2, 2.5, and 3 mm were measured. The values relative to the retentive force without displacement were gradually decreased to 82.7 ± 16.3%, 68.8 ± 17.1%, 62.4 ± 15%, 47.2 ± 13.1%, 35.7 ± 9.9%, and 20.7 ± 6.5%, respectively. The retentive force and magnetic field strength did not change significantly after the load test (100 N load, 10,000 times). No new gap between the metal and resin was found in the root keeper- and magnet assembly-embedded blocks after the load test. Some scratches on magnetic assembly and root keeper surface, while no change in the resin texture after the load test were observed. Based on the findings of this preliminary study, this novel low-cost magnetic attachment exhibited favorable retention, strength, and durability for clinical use.


Current development status of additive manufacturing technologies for fabricating removable partial denture frameworks: a literature review

The aim of the present study was to review the current development status of additive manufacturing (AM) technology for fabricating frameworks for removable partial dentures (RPDs) considering fit accuracy, surface condition, and mechanical strength. A search of the databases of MEDLINE, Cochrane Library, and Science Direct was conducted using definite keywords ("removable partial denture" or "framework" or "dental prosthesis design") and ("additive manufacturing technology" or "rapid prototyping" or "3D-printing"). A total of 23 articles were selected according to certain inclusion criteria. The direct AM techniques were applied to manufacture metal RPD frameworks consisting of selective laser melting (SLM), selective laser sintering (SLS), and metal binder jetting (MBJ). The SLM technique showed a good surface and mechanical strength, but low accuracy. The SLS technique showed higher accuracy than indirect AM, but further studies are required. The MBJ technique showed lower accuracy and a rougher surface than the conventional method. AM techniques can produce RPD frameworks within the acceptable range for clinical practice; however, more clinical studies are needed.

International Journal of Computerized Dentistry


Metal Allergy Mediates the Development of Oral Lichen Planus via TSLP-TSLPR Signaling

Metal allergy is a T-cell-mediated delayed type of hypersensitive reaction. The pathogenetic mechanisms underlying the allergy are unclear, although the condition has been reported to be related to oral lichen planus (OLP), despite an absence of immunological studies to support this relationship. In this study, histopathological samples of OLP patients were examined to compare the metal allergy-positive and -negative groups, with a focus on the network of epidermal keratinocytes and T cells induced by thymic stromal lymphopoietin (TSLP) and its receptor, TSLPR. Infiltration of T cells into the epithelium was revealed to be higher in the OLP lesions of metal allergy-positive patients than in those of metal allergy-negative patients. Moreover, TSLP-TSLPR signaling and TNF-α production were higher in the epithelial tissue samples of the metal allergy-positive patients than in the metal allergy-negative patients. Metal allergy is associated with both increased expressions of TSLP in keratinocytes and increased TNF-α levels in the epithelium. We propose that this would promote the accumulation of T cells at the lesion site, contributing to the formation of the disease. These results suggest that metal allergy may be an aggravating factor in the pathogenesis of OLP.


Does Prosthodontic Treatment Improve the Nutrition Status in the Elderly? Literature Review


Measurement of ultrasonic echo intensity predicts the mass and strength of the tongue muscles in the elderly


Relationship between oral susceptibility assessment and prefrontal cortex blood flow during occlusal force maintenance tasks

口腔内の感受性評価と咬合力維持タスク中における前頭前野の血流量との関連

The purpose of this study was to clarify the relationship between the periodontal tactile sensation and the activity of the prefrontal cortex. Eleven young, healthy Japanese participants (mean age 28.0±3.7 years) volunteered to participate in this study. We tested either the left side central incisors or the first molars. The periodontal tactile sensation of each tooth was evaluated using calibrated monofilaments (von Frey hairs). A magnitude estimation method was used as a psychophysical method, and the periodontal ligament tactile and periodontal tactile sensation values were determined by Stevens' power law. Prefrontal cortex activation was evaluated using a wearable functional near-infrared spectroscopy device that measured cerebral blood flow, and the experimental task involved maintaining occlusal force within an instructed range. The logarithmic values of the physical and sensory quantities of periodontal tactile sensation showed a linear relationship, and had a significantly high correlation coefficient. Regarding the periodontal tactile sensation values, no significant difference was found between the central incisors and first molars. In the molar teeth, negative correlations were found between the periodontal tactile sensation values and the cerebral blood flow in all measurement fields. Moreover, the mean occlusal force value of molars was below the instructed range, and showed significantly lower values compared to those of anterior teeth. Based on the above results, it was shown that Stevens' power law can be applied to periodontal tactile sensation, and the periodontal tactile sensation value in molars calculated from Stevens' power law is related to the cerebral blood flow in the prefrontal cortex and inhibition of occlusal force. The site-specific importance of the periodontal tactile sensation value was suggested during the task of maintaining occlusal force.

本研究では，歯根膜の触・圧覚への感覚刺激と前頭前野の活動の関連性を明らかにすることを目的とした．健常有歯顎を有する若年者11名を対象とし，対象歯は，上下顎左側中切歯および第一大臼歯とした．歯根膜触・圧覚の測定にはvon Freyの刺激毛を用いた．精神物理学的手法として，マグニチュード推定法を用い，Stevensのべき法則より歯根膜触・圧覚感受性値を算出した．前頭前野の血流量の測定には，ウェアラブル光トポグラフィーを用い，実験タスクとして，咬合力維持タスクを設定した．歯根膜触・圧覚の刺激物理量と感覚量の対数値はほぼ直線の関係を示し，有意に高い相関係数を示した．歯根膜触・圧覚感受性値に関しては，前歯と臼歯の間で有意な差は認められなかった．臼歯においてはすべての測定野で感受性値と血流の変化量との間に負の相関関係が認められた．また咬合力に関しては，臼歯のほうが前歯と比較し，有意に低い値を示した．以上の結果より，歯根膜触・圧覚において「Stevensのべき法則」が適用できることが示され，臼歯においてはその法則から導き出される感受性値が，前頭前野の血流量と咬合力の抑制に関連することが示され，咬合力維持というタスクにおける感受性値の部位特異的な重要性が示唆された．

The Journal of the Japanese Academy of Occulusion and Health


Treatment outcomes of implant-assisted removable partial denture with distal extension based on the Kennedy classification and attachment type: a systematic review

Implant-assisted removable partial dentures (IARPDs) have recently become popular, but little information is available on the treatment outcomes based on the Kennedy classification and attachment types. The objective of this review was to evaluate the treatment outcomes of IARPD delivered for distal extension edentulous areas based on the differences in the Kennedy classification and attachment type. English-language clinical studies on IARPD published between January 1980 and February 2020 were collected from MEDLINE (via PubMed), the Cochrane Library (via the Cochrane Central Register of Controlled Trials), Scopus online database, and manual searching. Two reviewers selected the articles based on pre-determined inclusion and exclusion criteria, followed by data extraction and analysis. Eighty-one studies were selected after evaluating the titles and abstracts of 2410 papers. Nineteen studies were finally included after the perusal of the full text. Fourteen studies focused on Class I, 4 studies investigated both Class I and II, and only 1 study was conducted on Kennedy's class II. Eight types of attachments were reported. The ball attachment was the most frequently used attachment, which was employed in 8 of the included studies. The implant survival rate ranged from 91 to 100%. The reported marginal bone loss ranged from 0.3 mm to 2.30 mm. The patient satisfaction was higher with IARPD than with conventional RPDs or that before treatment. The results of prosthetic complications were heterogeneous and inconclusive. IARPD exhibited favorable clinical outcomes when used as a replacement for distal extension edentulous areas. The comparison between the clinical outcomes of Kennedy's class I and II was inconclusive owing to the lack of studies focusing on Kennedy Class II alone. The stud attachment was the most commonly used type in IARPDs. Overall, the different attachment systems did not influence the implant survival rate and patient satisfaction. Further high-quality studies are needed to investigate the attachment systems used in IARPD.

International Journal of Implant Dentistry


Objective Assessment of Poor Oral Hygiene Using the ATP Swab Test in the Elderly

高齢者におけるATP拭き取り検査による口腔衛生状態不良の客観的評価

 Purpose:The purpose of this study was to evaluate the assessment of poor oral hygiene using the ATP swab test.

 Method:A total of 102 consecutive elderly outpatients aged ≥65 years who visited for maintenance were enrolled between October 2019 and April 2020. The evaluation of poor oral hygiene included measurements of:Tongue Coating Index(TCI), number of bacteria by a rapid oral bacterial detection device(Bacterial Counter DU-AA01NP-H;Panasonic Health Care, Japan), and amount of ATP+AMP by the ATP swab test(Lumitester;Kikkoman, Japan). The specimens were a gargle solution rinsed with 10 mL of water for 5 seconds as soon as the patients came to the hospital or a cotton swab wiped on the tongue dorsum. The subjective assessment of hygiene of the oral mucosa and dentures was rated on a 5-point scale.

 Results:In the assessment of tongue dorsum hygiene, the number of bacteria and the amount of ATP+AMP were significantly correlated with TCI. There was also a significant correlation between the number of bacteria and the amount of ATP+AMP.

 Conclusion:The results of this study suggested that the ATP swab test might be used to objectively assess overall poor oral hygiene, including food residues.

 目的:ATP拭き取り検査キットを用いた口腔衛生状態不良の評価方法について，口腔機能低下症で示された評価法と比較し検討することを目的とした．

 方法:2019年10月から2020年4月までの間に徳島大学病院歯科にてメンテナンスを行っている高齢者102名に対し，残存歯数の測定および口腔衛生状態不良の検査を行った．口腔衛生状態不良の検査では，舌苔付着度(Tongue Coating Index，TCI)，細菌数測定装置による細菌数測定，およびATP拭き取り検査キットによるATP+AMP量の測定を行った．被検体は来院時すぐに10 mLの水で5秒間含嗽を行って吐き出した含嗽溶液と綿棒で舌背部を拭ったものとした．また，口腔内の衛生状態の包括評価として，5段階で口腔粘膜および義歯の主観的評価を行った．

 結果:舌背部の測定に関して，ATP拭き取り検査値とTCIにおけるSpearmanの順位相関係数は0.374(p<0.001)，TCIと細菌数における相関係数は0.429(p<0.001)，細菌数とATP拭き取り検査値における相関係数は0.388(p<0.001)であった．また，包括評価に関して，口腔粘膜の衛生状態とATP拭き取り検査(舌背部)，ATP拭き取り検査(含嗽溶液)，TCI，細菌数(含嗽溶液)との相関係数はそれぞれ-0.257(p＝0.009)，-0.274(p＝0.005)，-0.209(p＝0.035)，-0.321(p＝0.001)であった．義歯の衛生状態とATP拭き取り検査値(含嗽溶液)，TCIとの相関係数はそれぞれ-0.317(p＝0.001)，-0.232(p＝0.019)であった．

 結論:ATP拭き取り検査キットによる測定は，食物残渣などを含む総合的な口腔衛生状態不良を客観的に評価できる可能性が示唆された．


Clinical Statistical Study of New Patients in Oral Implant Center at Tokushima University Hospital

徳島大学病院口腔インプラントセンターにおける新来患者の臨床統計

Purpose: Oral Implant Center established in April 2014 as specialized clinical section at Tokushima University Hospital. The aim of this study was to report a survey of new patients of preoperative registration at Oral Implant Center during the five years since its establishment.
 Subjects and methods: Investigation of gender and age, chief complaint, details of treatment requests, sites of missing teeth, number of missing teeth, cause of tooth extraction, and treatment status for patients registered at Oral Implant Center from April 2014 to March 2019 were performed.
 Results: Regarding the chief complaint, 605 (88.3%) patients consulted preoperatively for a request for implant treatment, and 80 (11.7%) consulted about complain of previous implant treatment or a request for continued maintenance. The average number of missing teeth for which treatment was requested was 3.8. The proportion of patients who wished to be treated for the number of missing teeth was 32.2% for missing one tooth, 56.1% for missing few teeth (2 to 6 teeth), 7.8% for missing many teeth (7 or more teeth) and edentulous 3.9%. As for the details of treatment requests of 80 patients who had already received implant treatment, 33 (41.3%) consulted on the improper superstructure, 29 (36.3%) wished to examine and treat peri-implantitis, 4 (5%) wished to remove the implant and 14 (17.5%) requested continued maintenance.
 Discussion and conclusion: The number of new patients regarding implant treatment has been about the same each year, and it was reconfirmed that it was recognized as a treatment method for dental prostheses. In particular, many patients wished to receive implant treatment for a single tooth missing, suggesting that the patients also recognized the importance of preserving the remaining teeth. On the other hand, the number of patients complaining of previous implant treatment tends to increase, and it is necessary to consider future correspondence.


Multivariate analysis reveals oral health-related quality of life of complete denture wearers with denture adhesives: a multicenter randomized controlled trial

Purpose To investigate the difference in improvement of oral health-related quality of life (OHR-QoL) depending on the oral and denture conditions of a complete denture wearer when using a cream or powder type denture adhesive in a 10-center parallel randomized clinical trial.

Methods Two hundred edentulous subjects who wore complete dentures were allocated to each of the three groups according to denture adhesive type: cream, powder, and control (saline solution). The materials were applied to the mucosal surface of the dentures for 4 days, and baseline data and data after the intervention were collected. OHR-QoL was assessed using the Japanese version of the modified Oral Health Impact Profile for Edentulous Patients (OHIP-EDENT-J) scale for outcome. Multivariate analysis was used to investigate improvements in OHR-QoL according to participant characteristics among complete denture wearers using these materials.

Results OHIP-EDENT-J scores were significantly decreased in all groups after the intervention (p < 0.05); however, there were no statistically significant differences among the groups. Multiple logistic regression analysis revealed a significant association between the vertical height of the maxillary and mandibular alveolar ridge and OHIP-EDENT-J scores in the cream-type denture adhesive group. In contrast, there were no significant association between participant characteristics and OHIP-EDENT-J scores in the powder-type adhesive and control groups.

Conclusions The use of denture adhesives could improve OHR-QoL for complete denture wearers. The cream-type denture adhesives may be expected to improve OHR-QoL in patients with poor residual ridge conditions compared with patients with good residual ridge conditions.


Does Masticatory Ability Contribute to Nutritional Status in Older Individuals?

Mastication plays a primary role in the process of eating. Hence, compromised masticatory ability may affect the nutrition and quality of life, which are particularly important concerns among older individuals. It remains unclear how is the masticatory ability assessed regarding the nutritional status. We examined the effect of various oral factors on three masticatory ability tests conducted among older individuals. A total of 100 older individuals were enrolled in this study. Body mass index (BMI) as an indicator of nutritional status; and age, sex, and the number of occlusal and molar occlusal supports as clinical attributes were recorded. Three masticatory ability tests (masticatory efficiency, masticatory score, and satisfaction with mastication) were conducted, and tongue pressure, cheek pressure, and occlusal force were assessed as oral functions. A significant but weak correlation was found between masticatory efficiency and the masticatory score, but not between masticatory efficiency and satisfaction score. Objective masticatory efficiency was strongly associated with objective oral factors, whereas subjective assessments of masticatory ability (masticatory score and satisfaction score) were not. Furthermore, BMI was significantly associated with subjective assessments of masticatory ability but not with objective masticatory efficiency. Both subjective and objective assessments of masticatory ability, along with considerations of nutritional formulations, are required for the maintenance and improvement of nutritional status in older individuals.

International Journal of Environmental Research and Public Health


Reliability of screening methods to diagnose oral dryness and evaluate saliva secretion


Does periodontal tactile input uniquely increase cerebral blood flow in the prefrontal cortex?

We previously studied the effect of peripheral sensory information from sensory periodontal ligament receptors on prefrontal cortex (PFC) activity. In the dental field, an alternative dental implant without periodontal sensation can be applied for missing teeth. In this study, we examine whether periodontal tactile input could increase cerebral blood flow (CBF) in the PFC against elderly patients with dental implants lacking periodontal tactile (implant group), elderly individuals with natural teeth (elderly group), and young individuals with natural teeth (young group). The experimental task of maintaining occlusal force as closed-loop stimulation was performed. Compared with the young group, the elderly group showed significantly lower CBF. Contrastingly, compared with the young group, the implant group showed significantly lower CBF. There were no significant differences between the elderly and implant groups. Regarding the mean occlusal force value, compared with the young group and the elderly group, the implant group had a numerically, but not significantly, larger occlusal force exceeding the directed range. In conclusion, the periodontal tactile input does not uniquely increase PFC activity. However, increased CBF in the PFC due to the periodontal tactile input in the posterior region requires existing attention behavior function in the PFC.


Effect of denture adhesives on oral moisture: A multicenter randomized controlled trial

The purpose of this study was to investigate the effect of denture adhesives on oral moisture in a 10-center parallel randomized clinical trial. Two hundred edentulous subjects wearing complete dentures were allocated into three groups: cream-type adhesive, powder-type adhesive and control groups. The adhesives (and saline solution in the control group) were applied to the mucosal surface of the dentures for 4 days, and baseline data and data after the intervention for eight meals over 4 days were obtained. For the main outcome, oral moisture was measured with a moisture checking device. Secondary outcomes were denture satisfaction, masticatory performance, denture retention, and occlusal force. In addition to between-group and within-group comparisons of oral moisture, investigations for secondary outcomes were undertaken in subgroups classified according to the degree of oral moisture at baseline (normal subgroup and dry mouth subgroup). Intention-to-treat analysis was also performed. Between-group and within-group comparisons of oral moisture showed no significant differences. The cream-type and powder-type denture adhesives were significantly effective in the dry mouth group for denture satisfaction ratings of ability to masticate, stability, retention, and comfort of mandibular dentures (p<0.05). The masticatory performance and retentive force of the dry mouth denture adhesive using groups were significantly improved after intervention (p<0.05). The oral moisture of complete denture wearers was not influenced by the use of denture adhesives. Our findings showed that denture adhesives improved subjective denture satisfaction, masticatory performance, and retention for complete denture patients with oral dryness.


Effect of Semaphorin7A during the Effector Phase of Nickel Allergy


Number of functional teeth more strongly predicts all-cause mortality than number of present teeth in Japanese older adults.

Previous studies on the association between intraoral conditions and mortality in community-dwelling older individuals reported that fewer present teeth (PT) are significant risk factors for mortality. However, how the number of PT relative to the number of functional teeth (FT), including both present and rehabilitated teeth, influences mortality has not been investigated fully. This study examined the impact of the number of FT on mortality among community-dwelling Japanese older adults. This study was a retrospective, observational and population-based follow-up study, which examined 1188 older individuals who participated in an annual geriatric health examination from 2009 to 2015. The average follow-up period was 1697.0 774.5ays. The primary outcome was all-cause mortality at follow-up. The numbers of PT and FT of each participant were counted during an oral examination. In addition, demographics, clinical variables, blood nutrient markers, physical functions and perceived masticatory function were measured. Kaplan-Meier analysis, followed by a log-rank test, revealed that fewer PT (P < 0.001) and FT (P = 0.002) were significantly associated with a reduced survival rate. Cox's proportional hazard analysis indicated that the number of FT, but not the number of PT, was a significant independent mortality risk factor after adjusting for demographics, clinical variables, nutrient markers and physical functioning (P = 0.036, hazard ratio: 2.089). Current results suggest that the number of FT more strongly predicts all-cause mortality than the number of PT among community-dwelling older adults. Further studies are necessary to consider the confounding of socioeconomic status and disability status. Geriatr Gerontol Int 2020; : - .


Geometric assessment of imaging methods for complete denture form: Comparisons among cone-beam computed tomography, desktop dental scanning, and handheld optical scanning.


消滅可能性地域における後期高齢者の社会的フレイル傾向の実態と地域保健活動の可能性-美馬市木屋平の持続可能性に向けた通いの場の活用-

Journal of Shikoku Public Health Society


学生技能コンペティション「第1回JPS student clinical skills competition」

(公社)日本補綴歯科学会は，全国の歯学部学生を対象とした臨床技能コンペティション(課題:保険収載CAD/CAM冠を想定した支台歯形成，下顎右側第二小臼歯)を開催した．26校の代表者各1名が行った支台歯形成を審査し，上位6名の学生を選出した．これらの学生を対象としたオンサイトでの最終実技審査を行い，審査結果の公表および優秀者の表彰を同日に行った．審査は形成模型のデジタルスキャンデータを使用して算出されたテーパーと削除量を参考に，評価者による総括評価とした．事後アンケートでは肯定的な回答が寄せられ，特に参加学生にとって本企画が歯科技能向上に対する研鑽意欲を喚起するものであったことが明らかになった．(著者抄録)


Assessment of potential clinical cascade between oral hypofunction and physical frailty: Covariance structure analysis in a cross-sectional study

No report has yet examined the impact of oral hypofunction on physical frailty in relation to intra-relationships of physical frailty assessment items. The purpose of this study was to verify the potential of a clinical cascade between oral hypofunction and physical frailty, and especially to support the hypothesis that the influence of oral hypofunction on physical frailty is greater than the intra-relationships among elements of physical frailty and that sex differences significantly affect these relationships. The participants were 272 older adults (101 men and 171 women; mean age 75.1 ± 7.5 years). Maximum occlusal force (MOF) and oral dryness (OD), as indicators of oral hypofunction, and grip strength (GS) and walking speed (WS), as indicators of physical frailty, were measured. Mutual relationship of four variables was verified using covariance structure analysis. In men, three paths from MOF to WS and GS and from WS to GS were confirmed, and those from MOF to WS and from WS to GS were found to be significant (P < .01). In women, three paths from MOF to WS and GS and from WS to GS were also confirmed, as with the men, and those from MOF to WS and from MOF to GS were found to be significant (P < .01). Model adaptability was shown to be good for both men and women. The results suggest our hypothesis was verified, and it is expected that the early detection of oral hypofunction, that is MOF, may be important for assessing physical frailty, especially in women.


Bibliography on Academic Exchanges of Tokushima University Faculty of Dentistry with Seven Indonesian Faculties

Tokushima University Faculty of Dentistry has signed academic agreements with seven faculties in Indonesia, and joint international meetings between these Indonesian universities have been held biannually. Moreover, undergraduate student exchange programs have been executed every year with three faculties. Behind the development of these successful outcomes is a story of a large amount of effort by pioneers. The purpose of this article is to present the process and history of the academic exchanges of Tokushima University Faculty of Dentistry with Indonesian faculties at present and to discuss future exchange programs.


Effect of polishing protocols on the surface roughness of polyetheretherketone.

The purpose of this study was to evaluate the influence of various polishing protocols on the surface roughness of polyetheretherketone (PEEK) and identify an effective polishing method of dental prostheses at the chairside. The PEEK specimens were assigned to seven groups with different protocols: no additional polishing (NT); polishing using a rubber point (C); polishing using "silky shine" (S); polishing using "aqua blue paste" (A); protocol C followed by protocol S (CS); protocol C followed by protocol A (CA); and protocol C followed by protocols S and A (CSA). The surface roughness (Sa and Ra) of the polished surfaces was measured. The surface roughness decreased in the following order of groups: NT, C, S, CS, CSA, CA, and A. In Groups C and S, wide deep pits formed by abrasive grains of SiC paper were observed, whereas only fine linear structures were observed on the surface in other groups. With respect to the polishing protocol of PEEK, clinically acceptable surface roughness was obtained using a soft polishing brush and agent for more than 3 min.


治療の難易度を測定するプロトコルの妥当性の検討 ─(公社)日本補綴歯科学会による多施設臨床研究─


(公社)日本補綴歯科学会のイノベーションロードマップを語る

(公社)日本補綴歯科学会のイノベーションロードマップを語る


高齢者における身体的能力の低下とその意識との関係:咬合力，握力，歩行速度

高齢者における身体的能力の低下とその意識との関係:咬合力，握力，歩行速度

The Journal of the Japanese Academy of Occulusion and Health


アルコール含有義歯安定剤であるホームリライナーが呼気中アルコール濃度へ与える影響の評価


Prefrontal cortex activity induced by periodontal afferent inputs downregulates occlusal force

The prefrontal cortex (PFC) plays an important role in several cognitive functions, such as planning, decision making, and social behavior. We previously reported that periodontal sensory input significantly increases PFC activity during the motor task of maintaining occlusal (biting) force. However, the relationships between periodontal sensation, PFC activity, and the performance of motor tasks have not been evaluated in detail. Therefore, using functional near-infrared spectroscopy, we investigated PFC activity by monitoring changes in cerebral blood flow (CBF) to specific areas of the PFC that corresponded to changes in occlusal force generated during four different biting tasks: (1) occlusion with the central incisor with an interocclusal distance of 5 mm (BI-5 mm); or (2) 10 mm (BI-10 mm); (3) occlusion with the first molars with an interocclusal distance of 5 mm (BM-5 mm), or (4) 10 mm (BM-10 mm). Occlusion of molars generated increased PFC regional CBF as the interocclusal distance decreased (BM-10 mm vs BM-5 mm). No significant differences in CBF during occlusion of incisors were found when comparing 5 mm and 10 mm intercostal distances (BI-5 mm vs BI-10 mm). The mean occlusal force generated by BM-5 mm occlusion was significantly lower than that generated by BM-10 mm occlusion. Taken together, our results suggest that the PFC decreases efferent signaling to motor units, to reduce occlusal force generated when periodontal sensation, which is greater when the interocclusal distance is reduced, is primarily responsible for maintaining occlusal force in the absence of sensations from the temporomandibular joint and muscle spindles.


Investigating eating behaviors and symptoms of oral frailty using questionnaires

A questionnaire survey was conducted to investigate eating behavior and the subjective symptoms of oral frailty, and to examine the relationship between them. A total of 744 subjects with ages over 65 years were included. The questionnaire comprised 18 question items indicating eating behavior and seven question items indicating oral frailty. All items were assessed according to 4 grades on a scale of 1 (not applicable) to 4 (applicable). The total score of oral frailty gradually increased with age. Regarding the scores for "eating recognition" and "eating habits", no changes were observed, however the scores for "eating action" demonstrated a decreasing tendency with age and the scores of 85 years age group was significantly lower than the 65-69, 70-74, and 75-79 years age groups. As a result of multiple regression analysis, among the significant independent variable, the scores of "I do not chew foods well" under the category of "eating action" showed the highest standard partial regression coefficients for dependent variable of symptoms of oral frailty. The significant association was found between the eating behavior and subjective symptoms of oral frailty, and this study suggests that the good chewing habit might be an important criterion for the prevention of oral frailty.


Subjective Evaluation of Denture Adhesives: A Multicenter Randomized Controlled Trial.

Many reports show that denture adhesives improve the retention and stability of dentures. However, few randomized controlled trials have examined the effects of denture adhesives. This 10-center randomized controlled trial with parallel groups involving 200 edentulous patients wearing complete dentures aimed to evaluate the effects of short-term use of cream and powder denture adhesives. Patients were allocated into 2 cream- and powder-type adhesive groups and 1 control group. Intervention groups were treated with the 2 adhesives (1 each), and the control group received saline solution. Adhesive or control was applied to the denture-mucosal surface for 4 d, and data at baseline and after day 4 of intervention (i.e., 8 meals) were obtained. Patient satisfaction was evaluated with a 100-mm visual analog scale. Oral health-related quality of life was measured with the Japanese version of the Oral Health Impact Profile for Edentulous Patients. Perceived chewing ability was evaluated by a questionnaire regarding ease of chewing and swallowing food. Between-group comparisons were performed with Kruskal-Wallis tests with the Mann-Whitney test adjusted by Bonferroni correction. Within-group comparisons of pre- and postintervention measurements were performed with the Wilcoxon signed-rank test. Intention-to-treat analysis was also performed. Between-group comparisons showed no significant differences for general satisfaction or Oral Health Impact Profile for Edentulous Patients. However, significant differences in satisfaction with various denture functions with cream- and powder-type adhesives were seen in pre- and postintervention comparisons ( < 0.05). Significant differences were also observed for perceived chewing ability of hard foods ( < 0.05). These results suggest that although denture adhesives do not invariably improve denture function, they do affect subjective evaluations and possibly chewing of hard foods. Therefore, the effects of denture adhesive use are insufficient to resolve any fundamental dissatisfaction with dentures ( ClinicalTrials.gov NCT01712802 ). The results of this study suggest that denture adhesives should be applied under certain conditions; however, an appropriate diagnosis is important before application. These practice-based data provide information to establish evidence-based guidelines for applying denture adhesives.


The aplication and usefulness of virtual reality aimd at encouraging an understanding of and reducing and eliminating prejudice dementia patients among local residents

地域住民の認知症に対する理解の促進と偏見の軽減・除去に関するバーチャルリアリティ技術の応用と有用性

To demonstrate the usefulness of a virtual reality device that authentically portrays the emotions of dementia patients and their families (VR Dementia Experience) for encouraging an understanding of and reducing and eliminating prejudice towards dementia patients among local residents. In Prefecture T, Town N, 85 residents of Neighborhood A were chosen as the intervention group, and 95 residents of Neighborhood B were chosen as the non-intervention group. The VR Dementia Experience was provided only to the residents of Neighborhood A. Residents of both neighborhoods completed a 35-item questionnaire regarding their degree of understanding and prejudice towards dementia patients before and after the intervention. Seventy-seven residents of Neighborhood A and 82 residents of Neighborhood B were analyzed. Their gender, age, and pre-intervention test baseline values were equivalent in the degree of understanding and prejudice. Significant increases were observed in 9 of 35 items for Neighborhood A residents (7 understanding-related, 2 prejudice-related) and 2 items for Neighborhood B residents (1 understanding-related, 1 prejudice-related). To ascertain the usefulness of the VR Dementia Experience, we compared the number of items with a significant increase: 9/35 (25.7%) in Neighborhood A and 2/35 (5.7%) in Neighborhood B. An effect (≥ 20%) was observed among the residents of Neighborhood A. Furthermore, after exposure to the VR Dementia Experience, the connection between understanding, prejudice, and dementia was strengthened among the residents of Neighborhood A compared to the residents of Neighborhood B. The VR Dementia Experience is a useful tool for encouraging an understanding of and reducing and eliminating prejudice towards dementia patients among local residents. However, to encourage the widespread usage of the technology, we should compare results with other public awareness campaigns as well as make improvements to the device and its VR content.


Effect of the temperature of water on ultrasonic denture cleaning

Denture plaque is a biofilm composed of various microorganisms aggregated with saliva. Various denture cleansers and cleaning apparatuses have been developed and studied. However, the optimum water temperature for denture cleaning is unknown. Therefore, the present study investigated the effects of water temperature during ultrasonic denture cleaning. In vitro, resin disks with artificial Candida albicans biofilm were pressed onto Candida GE media after ultrasonic cleaning with water at different temperatures for 5 min. The media were subsequently cultured at 37°C for 24 h. The colonies formed were observed and colony areas were quantified using ImageJ software (US National Institutes of Health, Bethesda, MD, USA). In situ, the bacterial count and degree of cleanliness on the tissue surface of maxillary dentures were measured before and after ultrasonic cleaning with water at different temperatures for 5 min. Changes in bacterial counts and cleanliness were calculated for each temperature. The ratio of the area occupied by bacterial colonies in vitro and reduction rates in situ after cleaning with warm water were markedly less than those observed after cleaning with cold water. Therefore, ultrasonic denture cleaning with warm water is more effective.


多波長植物専用LED照射装置を用いた完全制御型水耕栽培システム

多波長植物専用LED照射装置を用いた完全制御型水耕栽培システム

LED総合フォーラム2019 in 徳島 論文集

LED総合フォーラム2019 in 徳島 論文集


Comparison between two assessment tests for oral hygiene: adenosine triphosphate + adenosine monophosphate swab test and bacteria number counting by dielectrophoretic impedance measurement


Use of a Polyetheretherketone Clasp Retainer for Removable Partial Denture: A Case Report

Clasp retainers made of metal alloys may be esthetically unappealing or cause allergic reactions. To investigate alternative materials, we used the nonfiller polyetheretherketone (PEEK) to fabricate the clasp retainer of a removable partial denture for the mandibular bilateral distal free-end abutment of an 84-year-old female. Two years later, few color and texture changes of PEEK were found macroscopically. The rest part and the clasp arm fitted well without any deformation. There were no particular occlusal or periodontal problems. Subjective satisfaction was expressed by both the practitioner and the patient.


歯磨剤に配合された顆粒成分のインプラント周囲溝への侵入性の調査

歯磨剤に配合された顆粒成分のインプラント周囲溝への侵入性の調査

Journal of Japanese Society of Oral Implantology

日本口腔インプラント学会誌


Geniohyoid muscle affects directly masticatory function: Evaluation using a decision tree analysis

To clarify the effect of geniohyoid (GH) muscle morphology and related function on masticatory ability using a decision-tree analysis. A total of 103 participants were enrolled. A cross-sectional area (CSA) of the GH muscle, neck circumference, body mass index, tongue pressure, jaw opening strength, and masticatory ability score were measured. The CSA of the GH muscle was selected as an independent variable for the first layer of the decision tree, with masticatory score as the dependent variable. These data suggest that the CSA of the GH muscle may have a large impact on the masticatory ability score when evaluating masticatory ability.

The International Journal of Prosthodontics


Antifungal and Mechanical Properties of Tissue Conditioner Containing Plant-Derived Component --- An In Vitro Study

To evaluate the antifungal activity and mechanical properties of a novel antifungal tissue conditioner containing Juncus powder. Juncus powder was mixed with GC tissue conditioner at concentrations of 2.5%, 5.0%, and 10.0% by mass. The cylindrical specimens of Juncus-mixed tissue conditioner (dimensions: 10 mm in diameter and 2 and 6 mm in height for antimicrobial and mechanical tests, respectively) were prepared. The specimens placed on the bottom of the 24-well tissue culture plate were cultured with Candida albicans CAD1 for 2 and 4 days. The proliferation of the C. albicans in the wells was determined by measuring the optical density of fungal culture, and the surface of the specimens were also observed by scanning electron microscopy (SEM). To assess the mechanical properties of the specimens, the fluidity and hardness of Juncus-mixed tissue conditioner were measured using the methods certified according to ISO 10139-1. Juncus-mixed tissue conditioner significantly exhibited growth inhibitory effect in a Juncus concentration-dependent manner after both 2- and 4- day cultures. SEM observation showed that the amount of C. albicans on Juncus-mixed specimens drastically decreased, and biofilm formation was markedly inhibited. Moreover, both mechanical properties were found to be within the ranges regulated and specified by ISO. These findings demonstrated that the tissue conditioner including Juncus powder has a significant growth inhibitory effect against C. albicans, and it is suggested that the application of Juncus-mixed tissue conditioner may prevent denture stomatitis and oral candidiasis in denture wearers.


Tongue thickness and its clinical significance


Radiographic investigation of the marginal bone loss on dental implants, a retrospective cohort study

Background: During functional loading, the design of the dental implant may have an effect on the response of marginal bone.
Objectives: The purpose of this study was to report the prevalence of peri-implantitis, and to compare radiographic parameters around Brånemark and Replace Select dental implants and evaluate whether disparities in the morphologic features of these two indistinct implant systems, particularly their abutment-implant attachment, had an influence on the health of surrounding tissues and marginal bone loss (MBL).
Materials and Methods: Collection of data was done at the Department of Fixed Prosthodontics, the Department of Maxillo-Facial Prosthodontics, and Oral Implant Center of Tokushima University Hospital, in Tokushima, Japan; between March 2003 and followed until January 2017. Patients who have been treated with the Replace Select internal type implant and the Brånemark variety were selected as cohort. Marginal bone level measurements were evaluated via periapical and panoramic radiographs taken at regular follow-up visit. These dimensions were calculated, starting from the orientation mark at the implant abutment interface to the bottommost perceived contact area of marginal bone with the aforementioned implant system. The change in the level of bone was estimated by calculating the variation involving an initial reference value and the follow-up values.
Results: An average loss of bone at 0.65 ± 1.51 mm (range 0.36 to 7.89 mm) in the Replace Select group was observed, while in the Brånemark group 0.7 ± 1.32 mm (range 0.62 to 8.64 mm) was observed. Spearman rank correlation exhibited a statistically significant positive correlation between progress of bone loss around implant body and interval from implantation in the Brånemark group, whereas in the Replace Select group it was not significant. The Brånemark group exhibited significant (P = 0.0269) negative correlation of MBL and its diameters, whereas the Replace Select group did not exhibit such correlation.
Conclusion: Within the limits of this study, it can be concluded that deviations in the morphologic attributes of these two diverse implant systems had an influence on the health of surrounding tissues and MBL. The Brånemark implants showed a significant increase in MBL (> 1.8mm) as the time of placement elapses. This marked MBL was greater in females than males, in posterior than in anterior, and in the narrow platform implants than the regular platform implants or the wide platform implants. On the other hand, results suggested that this bone loss was greater in the mandible than the maxilla, in single-unit implant crowns than multiple implant restorations in the Replace Select group.

Background: During functional loading, the design of the dental implant may have an effect on the response of marginal bone.Objectives: The purpose of this study was to report the prevalence of peri-implantitis, and to compare radiographic parameters around Brånemark and Replace Select dental implants and evaluate whether disparities in the morphologic features of these two indistinct implant systems, particularly their abutment-implant attachment, had an influence on the health of surrounding tissues and marginal bone loss (MBL).Materials and Methods: Collection of data was done at the Department of Fixed Prosthodontics, the Department of Maxillo-Facial Prosthodontics, and Oral Implant Center of Tokushima University Hospital, in Tokushima, Japan; between March 2003 and followed until January 2017. Patients who have been treated with the Replace Select internal type implant and the Brånemark variety were selected as cohort. Marginal bone level measurements were evaluated via periapical and panoramic radiographs taken at regular follow-up visit. These dimensions were calculated, starting from the orientation mark at the implant abutment interface to the bottommost perceived contact area of marginal bone with the aforementioned implant system. The change in the level of bone was estimated by calculating the variation involving an initial reference value and the follow-up values.Results: An average loss of bone at 0.65 ± 1.51 mm (range 0.36 to 7.89 mm) in the Replace Select group was observed, while in the Brånemark group 0.7 ± 1.32 mm (range 0.62 to 8.64 mm) was observed. Spearman rank correlation exhibited a statistically significant positive correlation between progress of bone loss around implant body and interval from implantation in the Brånemark group, whereas in the Replace Select group it was not significant. The Brånemark group exhibited significant (P = 0.0269) negative correlation of MBL and its diameters, whereas the Replace Select group did not exhibit such correlation.Conclusion: Within the limits of this study, it can be concluded that deviations in the morphologic attributes of these two diverse implant systems had an influence on the health of surrounding tissues and MBL. The Brånemark implants showed a significant increase in MBL (> 1.8mm) as the time of placement elapses. This marked MBL was greater in females than males, in posterior than in anterior, and in the narrow platform implants than the regular platform implants or the wide platform implants. On the other hand, results suggested that this bone loss was greater in the mandible than the maxilla, in single-unit implant crowns than multiple implant restorations in the Replace Select group.


A multi-centered epidemiological study evaluating the validity of the treatment difficulty indices developed by the Japan Prosthodontic Society

The Japan Prosthodontic Society developed a multi-axis assessment protocol to evaluate the complex variations in patients who need prosthodontic care, and to classify the level of treatment difficulty. A previous report found the protocol to be sufficiently reliable. The purpose of this multi-center cohort study was to evaluate the validity of this multi-axis assessment protocol. The treatment difficulty was evaluated using the multi-axis assessment protocol before starting prosthodontic treatment. The time required for active prosthodontic treatment, medical resources such as treatment cost, and changes in the oral health-related QOL before and after treatment, were evaluated after treatment completion. The construct validity of this protocol was assessed by the correlation between the dentist's pre-operative subjective assessment of the treatment difficulty, and the level of difficulty determined by this protocol. The predictive validity was assessed estimating the correlations between a "comprehensive level of treatment difficulty" based on the four axes of this protocol and total treatment cost, total treatment time, and changes in the oral health-related QOL before and after treatment. The construct validity of this protocol was well documented except for psychological assessment. Regarding the predictive validity, the comprehensive level of treatment difficulty assessed before treatment was significantly correlated with the three surrogate endpoints known to be related to the treatment difficulty (total treatment cost, treatment time, and improvement in the oral health-related QOL). To further clarify the validity of the protocol according to patients' oral condition, a subgroup analysis by defects was performed. Analyses revealed that treatment difficulty assessment before treatment was significantly related to one or two surrogate endpoints in the fully edentulous patients and the partially edentulous patients. No significant relationship was observed in the patients with mixture of full/partial edentulism and the patients with teeth problems, possibly due to the small sample size in these groups. This study revealed that the multi-axis assessment protocol was sufficiently valid to predict the level of treatment difficulty in prosthodontic care in patients with fully edentulous defects and with partially edentulous defects.


Duplicate complete dentures made by general digital devices: Evaluation of material properties and clinical trial

汎用デジタル機器を用いて製作した複製義歯:材料特性と臨床評価

Purpose: The purpose of this study was to investigate the validity of the process of duplicating complete dentures using general digital devices through the following tests: cytotoxicity test of materials used, adhesion test of materials to a silicone impression material and a self-curing resin, and questionnaires to operators on duplicate dentures in clinical situations.

Methods: The cell viability of mouse fibroblast-like cells in acrylonitrile- butadiene-styrene (ABS) and polylactic acid (PLA) were evaluated as a cytotoxicity test. The tensile strength between the silicone impression material/self-curing resin and ABS/PLA specimen was measured as adhesive strength using a universal testing machine. Six practitioners who used duplicate PLA complete dentures in 7 patients were asked to evaluate the duplicate denture using the original questionnaire.

Results: The cytotoxicity test showed that the cell viabilities in ABS and PLA were similar to that in acrylic resin at the cell culture times of 24, 48 and 72 hours. The adhesion test showed that the adhesive strength between the ABS/PLA and silicone impression material was significantly lower than that between the conventional self-curing resin and silicone impression material. Although the adhesive strength between the PLA and self-curing resin was low, there was no significant difference between the ABS and self-curing resin. The results of the questionnaire showed that the duplicate denture made of PLA would be of similar value compared to the conventional duplicate denture made of acrylic resin.

Conclusions: The present study suggests that the duplicate complete dentures made by our proposed digital process are clinically effective.

目的:われわれが提案した汎用デジタル機器を用いた複製義歯製作法の有用性を示すために，使用するアクリロニトリル-ブタジエン-スチレン(ABS)共重合樹脂，ポリ乳酸(PLA)樹脂の細胞毒性試験，シリコーン印象材および常温重合レジンとの接着試験，使用感に関する主観的評価を行った．

方法:細胞毒性試験では，ABS樹脂とPLA樹脂の浸漬液を用いてマウスの線維芽細胞様細胞の細胞生存率を測定した．接着試験では，専用の保持体にそれぞれの試験片を固定し，シリコーン印象材および常温重合レジンを圧接した後に，万能試験機を用いて引張試験を行った．使用感の評価には，専用の評価票を作成し，PLA製の複製義歯を使用する術者に回答させた．

結果:細胞毒性試験では，ABS樹脂，PLA樹脂ともに72時間までの細胞生存率の低下は認められなかった．接着試験では，トレー用レジンと比較して両試料ともにシリコーン印象材への接着強さは低かった．常温重合レジンとの接着強さでは，PLA樹脂は低かったが，ABS樹脂では従来のトレー用レジンと同等の接着強さであった．術者による複製義歯使用感の評価結果としては，従来のアクリルレジン製の義歯とほとんど変わらない評価が得られた．

結論:三次元プリンターで製作した複製義歯における材料的，臨床的評価から本術式の有効性が示唆された．


各年齢階層におけるオーラルフレイルと身体的フレイルに関連する兆候:アンケートによる実態調査


Changes in food bolus texture during mastication

The purpose of this study was to survey the changes that occur in bolus texture from intake to swallowing during the mastication process for four types of food materials and to identify how texture is related to the number of chews. We recruited 15 young Japanese participants for this study. The subjects were asked to spit the food bolus just before swallowing when eating four different foods: cracker, boiled rice, hard gelatine gel, and soft gelatine gel. Three physical properties (hardness, adhesiveness, and cohesiveness) were measured in the bolus after being chewed for 25, 50, 75, 100, and 125% of the normal number of chews. Occlusal force and pressure as well as stimulated whole saliva volume were also measured. Extensive variation in the number of chews existed between subjects, but minimal intra-subject variation was observed. Hardness was observed to decrease, whereas cohesiveness and adhesiveness increased in a chew-dependent manner for the cracker, soft gelatine gel, and hard gelatine gel, but not boiled rice. Bolus texture appears to be largely related to the number of chews. Hardness also tended to be influenced by occlusion. The adhesiveness and hardness of the boiled rice were also greatly influenced by saliva volume and occlusal force, respectively. Hardness is an important rheological factor in food bolus texture and likely plays a significant role in determining the appropriate number of chews. Adhesiveness and cohesiveness appear to be secondary factors in this process. We propose a model of oral processing for application in determining the appropriate number of chews for an individual. Hardness appears to be an important rheological factor in food bolus texture, with adhesiveness and cohesiveness being secondary aspects. When food is hard or difficult to swallow, chewing behavior will likely be more influenced by the perception of bolus texture.


Duplication of complete dentures using general-purpose handheld optical scanner and 3-dimensional printer: Introduction and clinical considerations

To introduce a new clinical procedure for fabricating duplicates of complete dentures by bite pressure impression using digital technology, and to discuss its clinical significance. The denture is placed on a rotary table and the 3-dimensional form of the denture is digitized using a general-purpose handheld optical scanner. The duplicate denture is made of polylactic acid by a 3-dimensional printer using the 3-dimensional data. This procedure has the advantages of wasting less material, employing less human power, decreasing treatment time at the chair side, lowering the rates of contamination, and being readily fabricated at the time of the treatment visit.


Reliability and validity of the patient disability-oriented diagnostic nomenclature system for prosthetic dentistry

The Japan Prosthodontic Society (JPS) has proposed a new diagnostic nomenclature system (DNS), based on pathogenesis and etiology, to facilitate and improve prosthodontic treatment. This system specifies patient disability and the causative factor (i.e. "B (disability) caused by A (causative factor)"). The purpose of this study was to examine the reliability and validity of this DNS. The JPS Clinical Guideline Committee assessed mock patient charts and formulated disease names using the new DNS. Fifty validators, comprising prosthodontic specialists and dental residents, made diagnoses using the same patient charts. Reliability was evaluated as the consistency of the disease names among the validators, and validity was evaluated using the concordance rate of the disease names with the reference disease names. Krippendorff's α was 0.378 among all validators, 0.370 among prosthodontic specialists, and 0.401 among dental hospital residents. Krippendorff's α for 10 validators (3 specialists and 7 residents) with higher concordance rates was 0.524. Two validators (1 specialist and 1 resident) with the highest concordance rates had a Krippendorff's α of 0.648. Common disease names had higher concordance rates, while uncommon disease names showed lower concordance rates. These rates did not show correlation with clinical experience of the validator or time taken to devise the disease name. High reliability was not found among all validators; however, validators with higher concordance rates showed better reliability. Furthermore, common disease names had higher concordance rates. These findings indicate that the new DNS for prosthodontic dentistry exhibits clinically acceptable reliability and validity.


Age-related changes in geniohyoid muscle morphology predict reduced swallowing function


Characterization of Swallowing Sound: Preliminary Investigation of Normal Subjects

The purpose of this study was to characterize the swallowing sound and identify the process of sound generation during swallowing in young healthy adults. Thirty-three healthy volunteers were enrolled and allocated into three experimental groups. In experiment 1, a microphone was attached to one of eight cervical sites in 20 subjects, participants swallowed 5 ml water, and the sound waveform was recorded. In experiment 2, 10 subjects swallowed either 0, 5, 10, or 15 ml water during audio recording. In addition, participants consumed the 5 ml bolus in two different cervical postures. In experiment 3, the sound waveform and videofluoroscopy were simultaneously recorded while the three participants consumed 5 ml iopamidol solution. The duration and peak intensity ratio of the waveform were analyzed in all experimental groups. The acoustic analysis of the waveforms and videofluoroscopy suggested that the swallowing sound could be divided into three periods, each associated with a stage of the swallowing movement: the oral phase comprising posterior tongue and hyoid bone movement; the pharyngeal phase comprising larynx movement, hyoid bone elevation, epiglottis closure, and passage of the bolus through the esophagus orifice; and the repositioning phase comprising the return of the hyoid bone and larynx to their resting positions, and reopening of the epiglottis. Acoustic analysis of swallowing sounds and videofluoroscopy suggests that the swallowing sound could be divided into three periods associated with each process of the swallowing movement: the oral phase comprising the posterior movement of the tongue and hyoid bone; the pharyngeal phase comprising the laryngeal movement, hyoid bone elevation, epiglottis closure, and the bolus passage to the esophagus orifice; and the repositioning phase comprising the repositioning of the hyoid bone and larynx, and reopening of the epiglottis.


An innovative masticatory efficiency test using odor intensity in the mouth as a target marker: a feasibility study

A large number of studies have reported the findings for masticatory efficiency tests; however, some objective masticatory efficiency tests have a drawback, in that subjects are required to spit out the test material. This study examined the possibility of a masticatory efficiency test that evaluates the intensity of odours released when chewing an odour compound-containing material. A total of 20 volunteers were used in this study. The odour intensity in the breath after chewing a gum was measured by portable odour sensor device. The odour intensity after chewing the gum was measured over four chewing durations and at four intervals between spitting out and measurement of the odour intensity. The volume of stimulated saliva was measured by calculating the difference in the weight of the gauze before and after chewing to examine the effect of saliva flow. With an increase in chewing duration, odour intensity reduced. The odour intensity was the highest immediately after chewing. There was a positive correlation between odour intensity and gummy jelly-related masticatory efficiency test value (G-METV), which was significant for 10-s chewing. The regression equation was calculated from three objective variables of odour intensity and G-METV as dependent variable. Pearson's correlation coefficient between G-METV and the odour intensity-related masticatory efficiency value (O-METV) was 0·68. The coefficient of variation of O-METV was significantly lower than that of G-METV. These results suggest that the masticatory performance can be estimated by measuring the odour intensity immediately after chewing food containing odour compounds for 10 s.


Pathogenic factors in Candida biofilm-related infectious diseases.

Candida albicans is a commonly found member of the human microflora and is a major human opportunistic fungal pathogen. A perturbation of the microbiome can lead to infectious diseases caused by various micro-organisms, including C. albicans. Moreover, the interactions between C. albicans and bacteria are considered to play critical roles in human health. The major biological feature of C. albicans, which impacts human health, resides in its ability to form biofilms. In particular, the extracellular matrix (ECM) of Candida biofilm plays a multifaceted role and therefore may be considered as a highly attractive target to combat biofilm-related infectious diseases. In addition, extracellular DNA (eDNA) also plays a crucial role in Candida biofilm formation and its structural integrity and induces the morphological transition from yeast to the hyphal growth form during C. albicans biofilm development. This review focuses on pathogenic factors such as eDNA in Candida biofilm formation and its ECM production and provides meaningful information for future studies to develop a novel strategy to battle infectious diseases elicited by Candida-formed biofilm.


Periodontal tactile input activates the prefrontal cortex

The prefrontal cortex (PFC) plays a role in complex cognitive behavioural planning, decision-making, and social behaviours. However, the effects of sensory integration during motor tasks on PFC activation have not been studied to date. Therefore, we investigated the effect of peripheral sensory information and external information on PFC activation using functional near-infrared spectroscopy (fNIRS). Cerebral blood flow (CBF) was increased around bilateral Brodmann areas 46 and 10 during visual and auditory information integration during an occlusal force (biting) task. After local anesthesia, CBF values were significantly decreased, but occlusal force was similar. In conclusion, the effects of peripheral sensory information from the periodontal ligament and external information have minimal impacts on occlusal force maintenance but are important for PFC activation.


Magnet-retained two-mini-implant overdenture: Clinical and mechanical consideration.

Two-implant overdentures have become the accepted treatment for restoring mandibular edentulism. The dimensions of regular implants sometimes limit their use, such as in the case of narrow ridges. Mini-implants with reduced diameters (less than 3.0 mm) enable insertion into narrow ridges. A magnet-retained two-mini-implant overdenture system was developed and is described in this paper. Additionally, we describe a clinical mandibular procedure using the system and evaluate its biomechanical performance.


Hardness, cohesiveness, and adhesiveness of oral moisturizers and denture adhesives: selection criteria for denture wearers.

The mechanical properties of seven denture adhesives and eight oral moisturizers, all of which are commercially available, were evaluated using a texture pro le analysis. A new assessment chart is proposed for the selection criteria of denture adhesive and oral moisturizers using a radar chart with three axes: hardness, cohesiveness, and adhesiveness.


Part-digitizing system of impression and interocclusal record for complete denture fabrication

Few studies have reported the application of digital technology to removable dentures, particularly for the process of impression and interocclusal recording for complete denture fabrication. This article describes a part-digitizing system of impression and interocclusal records for complete denture fabrication. The denture foundation area in an edentulous mouth, including the border areas and residual ridge, is outlined by tracing the surfaces with a 3-D pen-type digitizer. Specialized trays for final impressions and interocclusal records were generated using computer-aided design and manufactured using the digital data. Final impression and interocclusal records were carried out using these specialized trays. The computer-aided method using preliminary digital impressions and specialized trays would be feasible for clinical use for complete denture fabrication.


Glass-fiber Reinforced 3-unit Metal-less Bridge: Short-term Preliminary Results

グラスファイバーで補強された高強度コンポジットレジンを用いた3ユニットブリッジ治療について(原著論文)

Mechanical strength to withstand occlusal force is required to the crown restorations of molars. Ag-Pd-Au alloy has been used as the acceptable material of the National Health Insurance system in Japan. However, the metallic color of prosthesis does not meet the aesthetic requirements of the patients, and there is also a problem to the provider side of the treatment that the price fluctuation is large by soaring material costs. A fiber reinforced metal-less bridge is proposed to resolve these problems and we began clinical application of this prosthetic treatment from September, 2012 on the approval of Tokushima University Hospital ethics committee. So far, six patients have been treated with 8 fiber reinforced bridges, and this treatment in Tokushima University Hospital was approved in Shikoku Regional Bureau of Health and Welfare as the advanced medical. We have followed the treatment for a maximum of more than two years, and it has been passed successfully with patient's satisfaction. Slightly problems which were caused in the hybrid resin material, could be easily solved by the direct procedures. This clinical results in short term suggested that the fiber reinforced metalless bridge have a sufficiently high therapeutic effect as a prosthetic method.


Digital assessment of preliminary impression accuracy for edentulous jaws: Comparisons of 3-dimensional surfaces between study and working casts

The aim of this study was to compare 3-dimensional surfaces of study and working casts for edentulous jaws and to evaluate the accuracy of preliminary impressions with a view to the future application of digital dentistry for edentulous jaws. Forty edentulous volunteers were serially recruited. Nine dentists took preliminary and final impressions in a routine clinical work-up. The study and working casts were digitized using a dental 3-dimensional scanner. The two surface images were superimposed through a least-square algorithm using imaging software and compared qualitatively. Furthermore, the surface of each jaw was divided into 6 sections, and the difference between the 2 images was quantitatively evaluated. Overall inspection showed that the difference around residual ridges was small and that around borders were large. The mean differences in the upper and lower jaws were 0.26mm and 0.45mm, respectively. The maximum values of the differences showed that the upward change mainly occurred in the anterior residual ridge, and the downward change mainly in the posterior border seal, and the labial and buccal vestibules, whereas every border of final impression was shortened in the lower jaw. The accuracy in all areas except the border, which forms the foundation, was estimated to be less than 0.25mm. Using digital technology, we here showed the overall and sectional accuracy of the preliminary impression for edentulous jaws. In our clinic, preliminary impressions have been made using an alginate material while ensuring that the requisite impression area was covered.


審美歯治療のエンドポイントと評価方法

審美歯治療のエンドポイントと評価方法


Development of a digital impression procedure using photogrammetry for complete denture fabrication

We developed an innovative procedure for digitizing maxillary edentulous residual ridges with a photogrammetric system capable of estimating three-dimensional (3D) digital forms from multiple two-dimensional (2D) digital images. The aim of this study was to validate the effectiveness of the photogrammetric system. Impressions of the maxillary residual ridges of five edentulous patients were taken with four kinds of procedures: three conventional impression procedures and the photogrammetric system. Plaster models were fabricated from conventional impressions and digitized with a 3D scanner. Two 3D forms out of four forms were superimposed with 3D inspection software, and differences were evaluated using a least squares best fit algorithm. The in vitro experiment suggested that better imaging conditions were in the horizontal range of ± 15 degrees and at a vertical angle of 45 degrees. The mean difference between the photogrammetric image (Form A) and the image taken from conventional preliminarily impression (Form C) was 0.52 ± 0.22 mm. The mean difference between the image taken of final impression through a special tray (Form B) and Form C was 0.26 ± 0.06 mm. The mean difference between the image taken from conventional final impression (Form D) and Form C was 0.25 ± 0.07 mm. The difference between Forms A and C was significantly larger than the differences between Forms B and C and between Forms D and C. The results of this study suggest that obtaining digital impressions of edentulous residual ridges using a photogrammetric system is feasible and available for clinical use.

International Journal of Computerized Dentistry


MiR-494-3p induced by compressive force inhibits cell proliferation in MC3T3-E1 cells.

Mechanical stimuli regulate fundamental cell processes such as proliferation, differentiation, and morphogenesis. We attempted to identify microRNA (miRNA) whose expression is changed during compressive treatment in MC3T3-E1, a pre-osteoblastic cell line. Microarray analysis followed by reverse transcription-quantitative polymerase chain reaction revealed that compressive force at 294 Pa for 24 h in MC3T3-E1 cells increased levels of miR-494-3p, miR-146a-5p, miR-210-3p, and miR-1247-3p. Among these miRNAs, miR-494-3p was found to inhibit cell proliferation in MC3T3-E1 cells. Furthermore, cells subjected to compressive force showed slower cell growth compared with control cells. Levels of mRNA for fibroblast growth factor receptor 2 (FGFR2) and Rho-associated coiled-coil kinase 1 (ROCK1), which were predicted to be targets of miR-494-3p, were decreased by compressive force or overexpression of miR-494-3p mimics in MC3T3-E1 cells. Furthermore, binding sites of miR-494-3p within 3'-untranslated regions of Fgfr2 and Rock1 were determined using luciferase reporter assay. In conclusion, compressive force affected expressions of several miRNAs including miR-494-3p in MC3T3-E1 cells. Compressive force might inhibit cell proliferation in osteoblasts by up-regulating miR-494-3p followed by FGFR2 and ROCK1 gene repressions.

Journal of Bioscience and Bioengineering


モールドレスプロセスによるチタン多孔体のインプラント上部構造への応用

モールドレスプロセスによるチタン多孔体のインプラント上部構造への応用

Journal of Japanese Society of Oral Implantology

日本口腔インプラント学会誌


インプラント上部構造における前装材破折と主機能部位との関連について

インプラント上部構造における前装材破折と主機能部位との関連について

日本口腔インプラント学会誌


Swallowing sound waveform and its clinical significance: Evaluation using ultrasonography

Background: Cervical auscultation is a technique frequently used for the screening of dysphagia. However, this method is difficult to evaluate objectively and it is unclear how sound is generated during the swallowing process. The aim of this study was to analyze the waveform of swallowing sound and clarify the sound production process using recordings of swallowing sounds and ultrasound images (USI), performed simultaneously.Materials and Methods: Commercial natural spring water and natural carbonated water were used in experiments 1 and 2, respectively. In experiment 1, a microphone was attached to the skin of the neck of 20 young participants and swallowing sounds were recorded and analyzed. In experiment 2, swallowing processes in three participants were recorded by a medical ultrasonography apparatus. The ultrasonic probe was placed on the skin over one of the thyroid cartilages or the thyroid gland.Results: The swallowing sound wave (SSW) was divided into three sectional periods. The mean duration of the first, second, and third SSW was 210 ± 147 ms, 458 ± 113 ms, and 91 ± 61 ms, respectively. The mean intensity ratio of the first, second, and third SSW was 7.8 ± 5.2, 29.2 ± 16.5,and 5.8 ± 5.1, respectively. When the ultrasonic probe was placed on the skin over one of the thyroid cartilages, in the phase between the production of the second SSW and the silent period, the USI revealed an accumulation of swallowed material around the valleculae and oropharynx. In the silent period of the second SSW, the swallowed material accumulated around the hypopharynx. When the ultrasonic probe was placed on the skin over the thyroid gland, in the silent period of the second SSW, the USI revealed that the swallowed material had passed through esophagus.Conclusion: Waveform and USI findings from this study suggest that swallowing sound can be divided into three sectional periods: an oral phase, a pharyngeal phase, and a repositioning phase.


End points and assessments in esthetic dental treatment.

There are two key considerations for successful esthetic dental treatments. This article systematically describes the two key considerations: the end points of esthetic dental treatments and assessments of esthetic outcomes, which are also important for acquiring clinical skill in esthetic dental treatments. The end point and assessment of esthetic dental treatment were discussed through literature reviews and clinical practices. Before designing a treatment plan, the end point of dental treatment should be established. The section entitled "End point of esthetic dental treatment" discusses treatments for maxillary anterior teeth and the restoration of facial profile with prostheses. The process of assessing treatment outcomes entitled "Assessments of esthetic dental treatment" discusses objective and subjective evaluation methods. Practitioners should reach an agreement regarding desired end points with patients through medical interviews, and continuing improvements and developments of esthetic assessments are required to raise the therapeutic level of esthetic dental treatments.


認知症患者の歯科的対応および歯科治療のあり方 学会の立場表明2015

認知症患者の歯科的対応および歯科治療のあり方 学会の立場表明2015


Influence of food volume per mouthful on chewing and bolus properties

Behaviors relating to food intake, i.e., speed of chewing, number of chews, and bite size, are important for decreasing energy intake, which might reduce excess body weight and thus metabolic risk. This study aimed at investigating the influence of mouthful volume on the number of chews and food bolus properties in addition to clarifying appropriate eating behaviors related to mouthful volume. Fifteen young Japanese women volunteered to participate. The subjects were asked to spit the food bolus in a glass dish just before swallowing when eating 3 different foods: boiled rice, fish sausage, and peanuts. The 3 physical properties of solidity, adhesiveness, and cohesiveness were measured in the bolus, and the number of chews was noted. The number of chews significantly increased with increasing mouthful volume with all 3 foods; conversely, the number of chews per unit of food weight (g) decreased significantly with boiled rice and fish sausage. Trends were observed for solidity and cohesiveness, which varied with increasing mouthful volumes. Decreased mouthful volume resulted in a greater number of chews per weight of food and more appropriate bolus properties; therefore, a change in mouthful volume could be a useful behavior modification for regulation of energy intake.


Literature Review of Setting the Occlusal Plane for Edentulous Patients

無歯顎補綴における咬合平面設定に関する文献考察

The maxillomandibular registration is one of important processes to achieve patientsatisfaction with the function and esthetics for complete denture fabrication. Over the years, clinical decision of vertical and horizontal jaw relationship has been mainly discussed in the maxillomandibular registration. With regard to the occlusal plane setting, many clinicians have believed to decide the occlusal plane parallel to Camper's plane, however there is little information on the effect of occlusal plane setting on clinical meanings and outcome. The aim of this study is to analyze published literature focusing on the occlusal plane and the related oral function and esthetics, and to clarify clinical implications of occlusal plane setting. Two databases, "PubMed" and "Japana Centra Revuo Medicina" were searched to retrieve research papers focusing on the occlusal plane.Seventy four papers were selected from the database, and they were reviewed.Literature reviews suggests that many landmarks were described on the occlusal plane setting for edentulous patients; and Camper's plane has been most frequently referred, showed a good result in function, but not always good in esthetics. The influence of occlusal plane setting on clinical results: oral function, esthetics, denture stability, and patient satisfaction after denture delivery has to be examined.


Influence of female attachment installation load on movement and resultant forces in implant overdentures

This in vitro study investigated the effect of attachment installation conditions on the load transfer and denture movements of implant overdentures, and aims to clarify the differences among the three types of attachments, namely ball, Locator, and magnet attachments. Three types of attachments, namely ball, Locator, and magnetic attachments were used. An acrylic resin mandibular edentulous model with two implants placed in the bilateral canine regions and removable overdenture were prepared. The two implants and bilateral molar ridges were connected to three-axis load-cell transducers, and a universal testing machine was used to apply a 50 N vertical force to each site of the occlusal table in the first molar region. The denture movement was measured using a G(2) motion sensor. Three installation conditions, namely, the application of 0, 50, and 100 N loads were used to install each attachment on the denture base. The load transfer and denture movement were then evaluated. The resultant force decreased with increasing installation load for all attachments. In particular, the resultant force on implants on the loading side of the Locator attachment significantly decreased when the installation load was increased from 0 to 50 N, and that for magnetic attachment significantly decreased when the installation load was increased from 50 to 100 N. For the residual ridges on the loading side, the direction of the forces for all attachments changed to downward with increasing installation load. Furthermore, the yaw Euler angle increased with increasing installation load for the magnetic attachment. Subject to the limitations of this study, the use of any installation load greater than 0 N is recommended for the installation of ball and Locator attachments on a denture base. Regarding magnetic attachments, our results also recommend installation on a denture base using any installation load greater than 0 N, and suggest that the resultant force acting on the implant can be decreased by increasing the installation load; however, a large installation load of 100 N should be avoided when installing the attachment on the denture base to avoid increasing the denture movement.


Evaluation of Eating Behavior and Mouthful Volume: Validity of YN Eating Behavior Questionnaire

一口量に着目した食行動評価:YN食行動質問票の有効性

We created a simple questionnaire to promote better eating habits and behavioral modification for the prevention and improvement of metabolic syndrome, examined its reliability and validity, and finally, assessed its effectiveness. A questionnaire, comprising of eighteen items to promote behavioral modification, was prepared comprising of three factors, "dietary recognition" , "eating habits" and "eating action" and was developed based on data from 125 students at the Faculty of Dentistry, The University of Tokushima. Furthermore, to assess the effectiveness of this version of the questionnaire, we conducted a survey on 845 health-care providers in Tokushima Prefecture and Hyogo Prefecture. The results confirmed a relatively high internal consistency with a Cronbach's alpha coefficient of 0.735–0.762 for the three factors. The questionnaire scores in the "obese" group with a body mass index of 25 or higher were high for all three factors and a significant difference was noted between the "normal" and "thin" groups under the category of "dietary awareness" . Moreover, trends between men and women; and between age groups were ascertained, therefore suggesting that this questionnaire is effective in assessing eating behavior associated with obesity.


補綴装置および歯の延命のために(Part 6) 力のコントロール 力を受ける生体側の観点から


Do sensation differences exist between dental implants and natural teeth?: a meta-analysis.

The purpose of this systematic review was to survey evidence pertaining to the sensation differences between natural teeth and osseointegrated dental implants. Using the MEDLINE (online PubMed) database, Cochrane Library, and Scientific Citation index, we performed a systematic search of articles. We used the following search terms: "perception or sensation and dental implant." The systematic review of the extracted articles was performed to see the sensation differences between natural teeth and dental implants. A total of six studies on oral sensation, "tactile sensibility," and "thickness discrimination" were included in the meta-analysis. As to the "tactile sensibility", all studies indicated the threshold levels of the implants were about 4-20 times higher than that of natural teeth. The tactile sensibility of an implant was significantly higher than that of a natural tooth, with an standardized mean difference (SMD) of 8.3619 (95% CI, 6.3920-10.3317) and a P < 0.0001. As to the "thickness discrimination", all studies indicated the threshold levels of implants were about 1.2-2.3 times higher than that of natural teeth. The thickness discrimination was significantly higher than that of natural teeth with an SMD of 1.2368 (95% CI, 0.8699-1.6038) and a P < 0.0001. This meta-analysis suggested that both tactile sensibility and thickness discrimination thresholds of implants were significantly higher than those of natural teeth. This meta-analysis reconfirms that sensation differences between dental implants and natural teeth exist.


The Influence of 1α.25-Dihydroxyvitamin D3 Coating on Implant Osseointegration in the Rabbit Tibia

This study aims to evaluate bone response to an implant surface modified by 1α,25-dihydroxyvitamin D3 [1.25-(OH)2D3] in vivo and the potential link between 1.25-(OH) 2D3 surface concentration and bone response. Twenty-eight implants were divided into 4 groups (1 uncoated control, 3 groups coated with 1.25-(OH)2D3 in concentrations of 10(-8), 10(-7) and 10(-6) M respectively), placed in the rabbit tibia for 6 weeks. Topographical analyses were carried out on coated and uncoated discs using interferometer and atomic-force-microscope (AFM). Twenty-eight implants were histologically observed (bone-to-implant-contact [BIC] and new-bone-area [NBA]). The results showed that the 1.25-(OH)2D3 coated implants presented a tendency to osseointegrate better than the non-coated surfaces, the differences were not significant (P > 0.05). The effect of 1.25-(OH)2D3 coating to implants suggested possible dose dependent effects, however no statistical differences could be found. It is thought that the base substrate topography (turned) could not sustain sufficient amount of 1.25-(OH)2D3 enough to present significant biologic responses. Thus, development a base substrate that can sustain 1.25-(OH)2D3 for a long period is necessary in future studies.

Journal of Oral & Maxillofacial Research


Relationship between mouthful volume and number of chews in young Japanese females

Objective: Modification of eating behavior in Japan is promoted to prevent overweight and obesity, but the effects of such modifications are unclear. This study aimed to clarify the inter- and intra-individual relationship between bite size and number of chews of food. Design and methods: Subjects comprised of 50 young healthy Japanese women (mean age 19.5 years). Food materials were boiled rice and apple. First, the average bite size and the number of chews per mouthful of food were calculated across the study cohort. The number of chews was counted by the subjects themselves and then self-reported. Correlation between the individual one-bite volume and the number of chews per volume was analyzed using Spearman's rank correlation coefficient. Second, the number of chews for three different sized bites of food (half of one bite, one bite, and one-and-a-half bites) were calculated as a prospective observational study. The number of chews for each of the three volumes of food was compared using one way ANOVA with Bonferroni correction. Results: For both food types, there was a negative correlation between individual mouthful volume and number of chews for both food materials. The number of chews per volume decreased as bite sizes increased. Conclusion: This study demonstrated an inter- and intra-individual relationship between bite size and the number of chews and suggested that smaller bite sizes were associated with more chews per volume of food.


Considerations on Olfactory Stimulus of <i>Citrus sudachi</i> and Thermo Stimulus to Promote Salivary Secretion

スダチのにおい刺激および温熱刺激による唾液分泌促進補助法の考案

In Japan, a country with an aging population, hyposalivation is becoming a serious problem among the elderly. The purpose of this study was to develop a new method for promoting salivary secretion using the olfactory stimulus of Citrus sudachi, artificial sudachi fragrance, and the combined use of artificial sudachi fragrance with thermo stimulus. Olfactory stimulus of Citrus sudachi is known as a safe stimulus that can stimulate salivary secretion of patients before food intake. However, Citrus sudachi is a seasonal fruit, so its effect was compared to that of artificial sudachi fragrance. The amount of saliva was recorded to evaluate the effect among 94 healthy adult participants who signed an informed consent form approved by the Research Ethics Committee of Tokushima University Hospital (#1283). Since olfactory stimulus easily fades, thermo stimulus was used because it is known to increase salivary secretion continuously. Thus,the effect of artificial sudachi fragrance combined with thermo stimulus using a hot pack on three different parts of the body (eyes, submandibular, chest) was also examined. Changes in salivary secretion was recorded for 1 hour after the stimulation. Results showed that artificial sudachi fragrance increased salivary secretion as much as Citrus sudachi. There was no significant difference between the olfactory stimuli of artificial sudachi fragrance when used alone, and when used in combination with thermo stimulus. However, it was observed that the stimulus which increased salivary secretion the most in 50 minutes was the olfactory stimulus with thermo stimulus on the submandibular. It can therefore be said that the combined use of olfactory stimulus with thermo stimulus is useful when saliva secretion becomes a concern among the elderly, especially at the start of food intake.

加齢や服薬に伴う唾液分泌能の低下は摂食・嚥下障害や誤嚥性肺炎につながる深刻な問題であり，有効な対策が求められている．本研究では，柑橘系のにおい刺激と顎顔面周囲への温熱刺激の併用によって唾液分泌を改善する方法を試みた．今回の試験では，スダチのにおいを実際の患者の食事に応用するにあたって，量産可能な代替香料の有効性(実験1)，および作用の持続(実験2)について検討した．対象者は，健常成人94 名(実験1:68 名，男性37 名，女性31 名，平均年齢24.3±2.1 歳，実験2:31 名，男性23名，女性8名，平均年齢25.5±3.9歳)とした． におい刺激剤としてスダチ果皮より抽出したスダチ精油と，スダチの香気成分資料をもとに精製したスダチ風人工香料を用いた．温熱刺激には，使い捨て温熱アイマスク(めぐリズム蒸気でホットアイマスク<sup>®</sup>無香料，花王株式会社)を用いた．におい刺激の有無と温熱刺激部位別に8 条件を設定し，1 時間の唾液分泌量の変化を比較した．唾液分泌量の測定にはワッテ法を用いた． 安静時を基準とした唾液の増加率において，スダチ精油とスダチ風人工香料間で有意な差は認められなかった．刺激後1 時間の唾液分泌量の変化より，におい刺激は刺激当初に，温熱刺激は徐々に唾液量の増加を促すことが示された．食事時のリハビリテーションへの応用には，食事のタイミングや食事時間を考慮した刺激の組み合わせが有効であることが示唆された．