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


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 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.


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.


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


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．


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


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.


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─


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.


Oral Hypofunction in the Older Population -Position Paper of the Japanese Society of Gerodontology in 2016

There is growing international interest in identifying the effects of ageing on oral health and on appropriate strategies for managing oral disorders. The Japanese Society of Gerodontology (JSG), as the official representative of researchers and clinicians interested in geriatric dentistry in Japan, makes several recommendations on the concept of "oral hypofunction." This study proposes diagnostic criteria and management strategies to reduce the risk of oral hypofunction among older people. We define oral hypofunction as a presentation of 7 oral signs or symptoms: oral uncleanness; oral dryness; decline in occlusal force; decline in motor function of tongue and lips; decline in tongue pressure; decline in chewing function; and decline in swallowing function. The criteria of each symptom were determined based on the data of previous studies, and oral hypofunction was diagnosed if the criteria for 3 or more signs or symptoms were met. We recommend that more evidence should be gathered from clinical studies and trials to clarify our diagnostic criteria and management strategies.


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


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.


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.


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.


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.


急性期病院入院高齢者における口腔機能低下と低栄養との関連性

急性期病院入院高齢者における口腔機能低下と低栄養との関連性


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.


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.


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.


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.


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．


Should Occlusal Pressure be Applied in Fixing Magnet Assenmlies to Denture? An Evaluation using the Delphi Technique

The Journal of the Japanese Sociaty of Magnetic Applications in Dentistry


Long-term follow-up case reports on the use of magnetic attachment as intracoronal/extracoronal attachments


In Vitro Efficacy of Electrolyzed Dilute Sodium Hypochlorite Solution on Candidal Biofilm

In vitroカンジダバイオフィルムに対する電解次亜水の効果

The effectiveness of oral care interventions for preventing aspiration pneumonia and barriers to compromised elderly is universally-recognized in present medical practice. Quick and effective methods and materials are needed for oral health care. An electrolyzed dilute sodium hypochlorite solution was chosen as a sterilizing solution for oral health care and the sterilizing effect was evaluated using an in vitro candida biofilm. Three electrolyzed functional waters, namely strongly alkaline water, weakly acidic water, dilute sodium hypochlorite solution, two kinds of commercial mouth wash and distilled water were used as test solutions. Antibiofilm efficacy and residual chlorine concentration were evaluated before/after immersing candidal biofilm specimens in each solution. pH changes of the solutions and macroscopic observations of metal surface were evaluated before/after immersing three kinds of dental metals: steel bar, cobalt-chromium alloy and gold-silver-palladium alloy in the solutions to test the corrosion behavior. An electrolyzed dilute sodium hypochlorite solution showed high bactericidal capability of candida biofilm on cell desks and stable concentration of available chlorine, but high induction of metal corrosion.

口腔ケアは，要介護高齢者などの誤嚥性肺炎の予防など易感染性宿主に対する感染症予防において，医療現場で高く認知されている．効果的な口腔ケアをするにあたって適切な洗浄剤や清掃材料が求められる．本研究は，強力な殺菌効果が期待される電解次亜水に着目し，そのカンジダバイオフィルムに対する洗浄効果の評価法を用いて，その有効性と可能性について検討した． 試験液として，強アルカリ性電解水，弱酸性電解水，電解次亜水，2種類の市販の洗口液，滅菌蒸留水，計6種類を用いた．カンジダバイオフィルムを形成させた被着試料を用いて，各試験液の抗バイオフィルム効果およびバイオフィルム浸漬前後の有効塩素濃度の変化を検討した．歯科用金属に対する腐食性を検討するために，スチールバー，歯科用コバルトクロム合金，金銀パラジウム合金，計3種類の歯科用金属を用いて，試験液浸漬前後の pH の変化を測定した．また，試料表面の肉眼観察も行った． 電解次亜水は高いカンジダバイオフィルム殺菌・洗浄効果を認め，安定した有効塩素濃度が確保されたものの，金属腐食作用は強いことが示唆された．


Reliability and validity of diagnostic nomenclature system of prosthetic dentistry

補綴歯科治療病名システムの信頼性と妥当性の検討

Purpose: The Japan Prosthodontic Society (a public interest incorporated association) proposed a new diagnostic nomenclature system method that is based on pathogenesis and etiology for providing adequate prosthodontic treatment to patients. This diagnostic nomenclature system is based on "factor" and "disability", and assumes that a disability is caused by a factor. The aim of this study was to analyze the reliability and validity of several dentists' diagnoses on mock patient charts.Methods: The Clinical Guideline Committee of the Japan Prosthodontic Society made mock patient charts and decided the disease name with the new diagnosis system. Fifty evaluators (prosthodontic specialists and hospital residents) answered the disease name with the new diagnosis system. The reliability and validity of the diagnoses were analyzed.Results: Krippendorff's α, which evaluates the reliability, was 0.378 (prosthodontic specialists) and 0.401 (hospital residents). The value was 0.524 with the top 10 evaluators, and 0.628 with the top 2 evaluators. There was no difference between the prosthodontic specialists and hospital residents in the correct answer rate. The correct answer rate for common dental diseases was high and that for uncommon dental diseases was low. Moreover, there was no relation between the correct answer rate and answering time or years of experience.Conclusion: The reliability of the answers among all evaluators was not high, but it was high among the evaluators who showed a high correct answer rate in this study. The correct answer rate for common dental diseases was high and that for uncommon dental diseases was low.

目的:(社)日本補綴歯科学会は病態とその発現機序の把握に基づく適切な補綴歯科治療を国民に提供するために，補綴歯科治療における新たな病名システムを提案した．これは患者に生じている「障害」を病名の基本とし，この障害を引き起こしている「要因」を併記して病名システムとするものであり，「A(要因)によるB(障害)」を病名システムの基本的な表現法としている．本研究の目的は考案した方法に従って決定した補綴歯科治療における病名の信頼性と妥当性を検討することである．方法:模擬患者カルテを作成し，(社)日本補綴歯科学会診療ガイドライン委員会で模範解答としての病名(以下，模範病名)を決定した．その後，合計50 名の評価者(日本補綴歯科学会専門医(以下，補綴歯科専門医)ならびに大学病院研修歯科医(以下，研修医))に診断をしてもらい，評価者間における病名の一致度(信頼性)ならびに(社)日本補綴歯科学会診療ガイドライン委員会による模範病名との一致度(妥当性)を検討した．結果:評価者間の一致度を検討するための算出したKrippendorff's αは全体では0.378，補綴歯科専門医では0.370，研修医では0.401 であった．Krippendorff's αは模範病名との一致度の高い上位10 名の評価者(補綴歯科専門医:3 名，研修医:7 名)では0.524，上位2 名の評価者(補綴歯科専門医:1 名，研修医:1 名)では0.648 と上昇した．日常的に頻繁に遭遇する病名に関しては模範病名との一致度が高かったが，日常的に遭遇しない病名は模範病名との一致度は低い状況であった．さらに，模範病名との一致度とアンケート回答時間や診療経験年数の関連性を検討したところ，相関関係はみられなかった．結論:全評価者間の一致度を指標とした本病名システムの信頼性は高くはなかったが，模範病名との一致度の高い評価者間では一致度が高かった．日常的に遭遇する補綴関連病名については模範病名との一致度が高かった．以上から(公社)日本補綴歯科学会の新しい病名システムは臨床上十分な信頼性と妥当性を有することが示唆された．


A Multi-Centered Epidemiological Study Evaluating the Reliability of the Treatment Difficulty Indices Developed by the Japan Prosthodontic Sociaty

補綴治療の難易度を測定するプロトコルの信頼性の検討 -(社)日本補綴歯科学会による多施設臨床研究-


Main occluding area in partially edentulous patients: changes before and after implant treatment

The 'main occluding area', the location where food crushing occurs during the first stroke of mastication, is reported to be an important concept; however, it is currently limited to findings in individuals with normal dentition. The purpose of this study was to assess the changes in the location, area and bite force of the main occluding area before and after implant treatments. We enrolled 50 partially edentulous and 22 normally dentate subjects. To identify the location of the main occluding area, each subject was instructed to freely bite once on a dental stopping using the partially edentulous side or the normally dentate area. The location, occluding contact area and bite force of the main occluding area before and after the implant treatments were analysed. The main occluding area was located at a reproducible location in the partially edentulous and normally dentate subjects. This location was principally the first molar region, and for the partially edentulous patients with missing teeth in the molar regions, it moved from the premolar region to the first molar region after treatment. The occluding contact area and bite force for the main occluding area increased (P < 0·05) after the implant treatment in the partially edentulous patients with missing teeth in the molar regions. These results suggest that the main occluding area can be restored to the first molar region after implant treatment and may be an important factor in the assessment of prosthodontic treatment.


MI sensor-aided screening system for assessing swallowing dysfunction: Application to the repetitive saliva-swallowing test

Assessment of swallowing dysfunction, particularly the risk of aspiration, is extremely important to clinicians because it provides crucial information for preventing morbidity and mortality from dysphagia. The purpose of this study was to describe a magneto-impedance sensor-aided screening system (MISS) for assessing swallowing function and clarify its effectiveness with the repetitive saliva-swallowing test (RSST). An MI sensor attached to the skin over the sternum detected the distance from a magnet attached to the skin over the thyroid cartilage during swallowing as the change of magnetic fields. The MISS was validated by videofluoroscopic and videoendoscopic observations. Further, the swallowing behavior of 93 individuals was assessed by using the MISS and then analyzed with the RSST. Swallowing behavior can be recorded and investigated objectively by signal inspection in the MISS compared with the conventional methods. The MISS is a simple and straightforward method for recording and safe because of dry swallow. The MISS system was validated by using simultaneous recordings with videofluoroscopic or videoendoscopic examinations, and compared with the conventional RSST method. The MISS combined with the RSST is an effective screening test for swallowing function.


Alternative Decision Making Considerations in Prosthodontics

The International Journal of Prosthodontics


Telescopic Magnetic Attachment for Implant-Supported Denture: Evaluation of Splint Effect

Retrievability, connecting strength, and ease of laboratory work are important but conflicting prerequisites for the success of an implant superstructure, particularly with regard to immediate function. To resolve this issue, a telescopic magnetic attachment system has been developed for implant-supported removable dentures. The splinting effect of the attachment was evaluated for stress distribution and elevation with an in vitro model of three implants in an edentulous mandible. Two types of telescopic magnetic attachments were prepared; the inclination angles of the axial wall of the abutment were 2.5 and 6.0 degrees. Three types of three-unit superstructures--a screw-retained superstructure and two telescopic magnet-retained superstructures--were fabricated. Static loads of 24.5, 49, and 98 N were applied vertically at three loading points on one side of each occlusal table. The elevation was measured as the height at which the magnet-retained superstructure detached from the abutment (on the other side of the prosthesis). In addition, by means of strain gauges, the stress distribution around the implants was evaluated and compared among the superstructures with the same three loads applied at six different points. The magnet-retained superstructure with the axial wall inclined at 2.5 degrees did not detach from the abutment. The differences in stress distribution between the screw-retained and magnet-retained superstructures with a 2.5-degree inclination were found to be statistically insignificant. The magnet-retained superstructure with a 6-degree inclination detached from the abutment, and the stress was concentrated during loading to a cantilever site. Because of its stress distribution and elevation, the new telescopic magnetic attachment, which has properties such as splinting the implants, ease of fabrication, and retrievability, is expected to be a viable alternative for the retention of implant-supported removable dentures.

The International Journal of Oral & Maxillofacial Implants


A new method to prevent the corrosion of dental materials, during disinfection using functional water: Sacrificial protection

This paper demonstrates a simple method using sacrificial protection for preventing the corrosion of dental metals. Dental metals are directly connected or/and wound with a pure commercial aluminum/zinc wire/plate with high ionization tendency, before their immersion into oxidizing functional water. Dental materials such as Co-Cr alloy wires, stainless steel, and Au-Ag-Pd alloys did not corrode when this method was used. Thus, this method is very simple and effective for preventing corrosion of dental metals during disinfection using functional water.


磁石固定式上部構造におけるインプラント支持歯槽骨の光弾性応力解析

磁石固定式上部構造におけるインプラント支持歯槽骨の光弾性応力解析

The Journal of the Japanese Society of Magnetic Applications in Dentistry


舌接触補助床(PAP)のガイドライン(案)

舌接触補助床(PAP)のガイドライン(案)


Implant prostheses and adjacent tooth migration: preliminary retrospective survey using 3-dimensional occlusal analysis.

Occlusal force analysis was retrospectively evaluated to clarify the proximal contact loss after fixed implant prosthesis placement. Twenty-eight patients (55 prostheses) with fixed implant prostheses in the posterior region were divided into 2 groups: proximal contact loss and unchanged groups. The occlusal force and its distribution were 3-dimensionally measured using the Dental Prescale system. A high proportion of lingual and anterior component forces and high occlusal force distribution in the intercanine region were observed in the contact loss group. The high occlusal force of the adjacent tooth may enhance the mesial migration.


Denture plaque microflora in geriatric inpatients and maxillary defect patients

Purpose: The purpose of this study was to investigate denture plaque microflora of geriatric inpatients and maxillary defect patients from the standpoint of infection control in the elderly.Methods: Denture plaque was collected from 80 elderly subjects who were categorized into 3 groups: group A, 21 healthy complete denture wearers; group B, 49 complete denture wearers residing at a geriatric hospital; and group C, 10 complete denture wearers with maxillary defects. The microflora was investigated by counting the total number of microorganisms, including streptococci, staphylococci, and Candida spp.Results: The colony-forming unit (CFUs) count and incidence, particularly those of Candida spp., were significantly higher in group B (P<0.01). The CFUs of staphylococci were significantly higher in group C (P<0.01), and methicillin-resistant Staphylococcus aureus (MRSA) was observed in all Staphylococcus-positive patients. The CFUs of Candida spp. were significantly correlated to those of staphylococci (P<0.01).Conclusion: A high CFU count of Candida spp. and staphylococci (including MRSA) are characteristic of the microflora in geriatric inpatients and maxillary defect patients, respectively. This study supports the hypothesis that dentures might serve as potential reservoirs of organisms causing systemic infections.


Improvement of Oral Condition of Elderly using Oral Rinse with Benzethonium Chloride

塩化ベンゼトニウム配合洗口液を用いた高齢者の口内環境の改善

日本補綴歯科学会雑誌. 特別号, 日本補綴歯科学会学術大会抄録集 = Proceedings of the ... conference, the Japan Prosthodontic Society


Influence of a Vent Hole on the Retentive Force of a Cement-retained Superstructure before/after Thermocycling

Purpose: The purpose of this study was to evaluate the influence of a vent hole on the retentive force of a cement-retained superstructure to an abutment.
Methods: The retentive force of superstructures with/without a vent hole, retained using one of two luting cements, was measured using a universal testing machine both before and after thermocycling
Results: The retentive force of the cement-retained superstructure with the vent hole was greater than that of the cement-retained superstructure without the vent hole. While the retentive force decreased significantly after thermocycling, the size of the vent hole had little influence on the retentive force.
Conclusion: It was concluded that placement of a vent hole in the superstructure is useful, with little adverse effect on the retentive force of the restoration.


In vitro Study of Stress Distribution on Additional Posterior Mandibular Implants

Purpose : This in vitro study investigated the influence of implant splinting on stress distribution in two experimental implant-bone models.Materials and Methods : Two experimental implant-bone models simulated the original Brånemark model with four implants between the mental foramina and one additional implant placed on each side posterior to the mental foramen. The stress distribution on each implant in the models was examined by applying a static load to the superstructure. Three types of superstructures were studied to determine the effect of additional implants in the posterior region : 1) a metal superstructure supported by all six implants (Full dental arch ; Metal FDA) ; 2) the same type of superstructure made of resin instead of metal (Resin FDA) ; and 3) the metal superstructure supported by four anterior implants, with the conical abutments removed from the two posterior implants (Short dental arch ; Metal SDA).Results : Regardless of the type of superstructure tested, high stress was observed around each loaded implant. The highest stress was concentrated on the distal implants of the FDA compared to the stress on the anterior implants.Conclusion : The elevated stress concentration around the implants found in the present in vitro study is considered to be one of the reasons for the high failure rate of additional posterior mandibular implants.


上顎全部床義歯の後縁設定に関する一考察

上顎全部床義歯の後縁設定に関する一考察


Influence of Changes in Occlusal Vertical Dimension on Tongue Pressure to Palate during Swallowing

Purpose : The purpose of the present study was to examine the relationship of tongue pressure and changes in occlusal vertical dimension to swallowing.Materials and Methods : The volunteer subjects were four young male dentulous adults and eight elderly complete denture wearers. The tongue pressure to the palate was simultaneously recorded with electromyography (EMG) measurements of the suprahyoid muscles as the occlusal vertical dimension changed. The subjects were instructed to perform two actions : swallowing without any liquid or food (dry swallowing) and swallowing of 2 ml water (wet swallowing).Results : During dry swallowing, the maximum pressure decreased significantly as the vertical dimension increased in the young subjects. In the elderly, the maximum tongue pressure decreased monotonically as the vertical occlusion increased. The same results were clearly found for wet swallowing. Overall data suggested that the tongue pressure of the elderly group was lower and the duration of tongue pressure in wet swallowing was longer than that of the younger group.Conclusion : An increase of the vertical dimension decreased the tongue pressure to the palate, whereas a decrease of the vertical dimension affected the tongue pressure less. Tongue pressure is an important factor for the evaluation of tongue function, especially swallowing.


デンチャープラークと咽頭の微生物叢との関連性

デンチャープラークと咽頭の微生物叢との関連性

Purpose: Prevention of an infection, especially aspiration pneumonia, is an important theme in the elderly. We are pointing out risk that is causing an infection such as the aspiration pneumonia, and a denture acts as a reservoir of microorganisms. The aim of this study was to examine the relationship between denture plaque and pharyngeal microflora in the elderly, and the drug susceptibility of isolated Candida spp.
Methods: We collected samples of denture plaque and pharyngeal plaque from elderly patients in a geriatric hospital and Tokushima University Dental Hospital (TUDH). The microflora was investigated by the detection of oral streptococci, staphylococci, Candida spp., Pseudomonas aeruginosa, Escherichia coli and coliforms, and MRSA. Isolated Candida spp. were measured for drug susceptibility.
Results: The microflora of denture plaque was very similar to pharyngeal microflora. A higher incidence of most microorganisms was observed in the patients in TUDH compared with patients in the geriatric hospital. Staphylococci were detected from the patients who harbored Candida spp. All strains of Candida spp. appeared to be susceptible to amphotericin B. Some strains of C. glabrata, C.tropicalis, and C. krusei appeared to be less susceptible to fluconazole. Fluconazole-resistant C. albicans was not isolated.
Conclusions: Denture plaque strongly influences the pharyngeal microflora in the elderly.

The Journal of the Japan Prosthodontic Society


A Study on the Contributing Factors that make Denture Usage Difficult for the Dependent Elderly

要介護高齢者の義歯使用を困難にする要因に関する研究

It is well known that whether the dependent elderly can use dentures or not depends on the degree of both their physical and mental capacities. However, we have observed several cases where two eldely persons having with similar levels of activities of daily living (ADL), a similar degree of independence in daily living, and a similar degree of dementia, differed significantly in their ability to use dentures properly.
From these cases, it can be hypothesized that the ability of the dependent elderly to use dentures properly depends not only on their actual oral condition and ADL, but also on various events in their lives such as the number of their admissions to the hospital since they started wearing dentures. In other words, the cumulative effect of various major life events influences the usage of dentures by the elderly.
Therefore, we conducted a survey designed to investigate the contributing factors that divide those elderly who wear dentures properly from those who do not .
The study participants were the edentulous individuals (71 in total; 16 males, 55 females. Average age: 85.0±5.9 years) who are residents in a geriatric hospital or in a facility of the health care servicesfor the elderly in Tokushima prefecture .
A survey was conducted on the above participants regarding their use of complete dentures, their ADL, their degree of independence for daily living, their degree of dementia, etc.
The results can be summarized as follows:
1 . The frequency of complete denture usage declined as the participant's levels of ADL, independence and dementia worsened, but this decline did not have any relationship to the times of theiradmissions to the hospital/facility or the numbers of members in their family.
2. It was suggested that, among the elderly who have a dementia and mild to low levels of ADL, their ability to wear/remove dentures and to clean the dentures by themselves relates significantly to the frequency of their denture usage .

要介護高齢者が義歯を使用できるか否かは, 身体的能力や精神的能力などによって影響されることが知られている．
しかし, 同等のADL, 日常生活の自立度や痴呆度でありながらも一方の高齢者では義歯が使用できるが, 他方の高齢者では義歯が使用できないといった事例を多々経験する．
要介護高齢者が義歯を使用できるか否かは, 単に現在の口腔内状態, ADLや痴呆度などに依存するだけでなく, 義歯を使用しなければならなくなって以来の入院歴や家族歴を始めとする人生における各種事象の影響が累積して形成された一種の生活習慣とも考えられる．
そこで, この義歯使用者と不使用者とを分ける要因を明らかにするために, 徳島県下の介護保険施設に入院・入所している上下無歯顎者 (男性16人, 女性55人, 合計71人, 平均年齢85.0±5.9歳) を対象に, 全部床義歯の使用・不使用, ADL, 口腔に関連するADL, 日常生活の自立度, 痴呆度などについて調査を行った．その結果, 以下のような結論を得た．
1.全部床義歯の使用率は, ADL, 口腔に関連するADL, 日常生活自立度, 痴呆度の悪化とともに低下したが, 入院・入所回数や同居家族数とは関連性がなかった．
2.痴呆がありADLが中等度あるいは低度の被験者群では, 義歯の着脱や口腔清掃が自分自身で可能か否かが義歯の使用率に大きく影響する可能性が示唆された．


Identification of Helicobacter Pylori in Denture Plaque of Hospitalized Aged Patients


Observation of Tongue Pressure to Palate at Swallowing --- Comparison between Young Dentitions and Elderly Complete Denture Wearers

嚥下時の口蓋に対する舌接触圧の観察 --- 若年有歯顎者と高齢総義歯装着者の比較


Efficacy of Electrolyzed Water as Denture Cleanser --- Influence on in vitro Biofilm of Candida albicans

義歯洗浄剤としての電解水の効果 --- in vitroのCandida albicansバイオフィルムへの影響


Denture Plaque Control for Prevention of Systemic Infection: Part 1. Identification of Helicobacter pylori in Denture Plaque. --- 第1報 デンチャープラーク中の胃潰瘍原因菌Helicobacter pyloriの検出

感染症予防のためのデンチャープラークコントロール --- 第1報 デンチャープラーク中の胃潰瘍原因菌Helicobacter pyloriの検出


Influence of Implant Connection on Mandibular Flexure in Jaw Movement --- Three-dimensional Finite Element Analysis

下顎運動時の下顎骨の変形に対するインプラント連結の影響 --- 三次元有限要素法による解析


A Basic Study on Pressure Distribution of Supporting Structures under Complete Denture --- Part 4. Influence of Occlusal Scheme on Pressure Distribution under a Denture

全部床義歯床下組織の負担圧分布に関する基礎的研究 --- 第4報 咬合様式の差が義歯床下組織の負担圧分布に及ぼす影響


Shear Bond Strength of Abrasion-resistant Plastic Teeth to Self-curing Resin --- Comparison of Bonding Agents

義歯用硬質レジン歯と即時重合レジンとの結合強さについて --- 各種ボンディング材の比較


Influence of the buccolingual position of artificial posterior teeth on the pressure distribution on the supporting tissue under a complete denture

The buccolingual position of artificial teeth is one of the important factors affecting denture stability, chewing efficiency, and pressure distribution on the supporting tissue under a denture. This study compared the pressure values on the supporting tissue under a denture during chewing in denture wearers, each of whom tried three different setting positions of artificial posterior teeth. The pressure on supporting tissue was greater on the working side that on the non-working side during chewing. The difference in mean pressure was found among the buccolingual positions of artificial posterior teeth. When the posterior teeth were set on the crest, the total pressure was the smallest. This strongly suggests that the setting position of artificial teeth should be considered not only for denture stability but also for the avoidance of high pressure on the supporting structures.


Shock-absorbing Behavior of Soft Denture Liner --- Part 2 Influence of Lining Design on Shock Absorbability

軟質裏装材の衝撃緩衝に関する研究 --- 第2報 裏装法の違いが衝撃緩衝能に与える影響


An In Vitro Study of the Influence of Occlusal Scheme on the Pressure Distribution of Complete Denture Supporting Tissue

The International Journal of Prosthodontics


Studies on Soft Denture Liner by using Viscoelastic Analysis --- Part 3. Effect of Viscosity of Soft Lining Materials on Stress Distribution in Denture Supporting Structures

粘弾性解析による軟質裏装材の有用性に関する研究 --- 第3報 軟質裏装材の粘性が床下組織の応力分布に及ぼす影響


A Basic Study on Pressure Distribution of Supporting Structures under Complete Denture --- Part 3. Influence of Occlusal Surface of Artificial Posterior Teeth on Pressure Distribution

全部床義歯床下組織の負担圧分布に関する基礎的研究 --- 第3報 臼歯人工歯の咬合面形態の差が負担圧分布に及ぼす影響

The Journal of the Japan Prosthodontic Society


Studies on Soft Denture Liner by using Viscoelastic Analysis --- Part 2. Effect of Lining Method of Denture Liner on Stress Distribution in Supporting Structures

粘弾性解析による軟質裏装材の有用性に関する研究 --- 第2報 軟質裏装材の裏装法の違いが床下組織の応力分布に与える影響


A Basic Study on Pressure Distribution of Supporting Structures under Complete Denture --- Part 2. The Influence of the Inclination of Incisal Guide Plate of Semi-adjustable Articulator on Pressure Distribution

全部床義歯床下組織の負担圧分布に関する基礎的研究 --- 第2報 咬合器の切歯路指導板の傾斜が負担圧分布に及ぼす影響


Shock-absorbing Behavior of Soft Denture Liner --- Part 1 Plate Specimens

軟質裏装材の衝撃緩衝に関する研究 --- 第1報 板状試料の衝撃緩衝能


Studies on Soft Denture Liner by using Viscoelastic Analysis --- Part 1 Effect of Soft Denture Liner on Stress Distribution in Supporting Structures

粘弾性解析による軟質裏装材の有用性に関する研究 --- 第1報 軟質裏装材が床下組織の応力分布に及ぼす影響


Viscoelastic Analysis of the Supporting Structures under Denture --- Part 1 Effect of the Artificial Teeth Arrangment on the Stress Distributions in the Supporting Structures

粘弾性解析による義歯床下組織の応力分布 --- 第1報 人工歯の配列位置が義歯床下組織の応力分布に及ぼす影響


The influence of soft lining materials on pressure distribution


A Guideline for Incisal Table Adjustment of Semi-adjustable Articulator LL-85R --- Part 2. The Adjustment of Incisal Table

LL-85R 咬合器の切歯路指導板の調節についての1基準 --- 第2報 切歯路指導板の調節法について


Stress Distribution of Supporting Tissues Under Denture --- Application of Viisco-elastic Analysis in Prosthetic Field

粘弾性解析による義歯床下組織の応力分布 --- 粘弾性解析の導入


Effect of viscoelastic deformation of soft tissue on stresses in the structures under complete denture


A Basic Study on Pressure Distribution of Supporting Structures under Complete Denture --- Part 1. Application of Pressure Dispersion Analyzing System by using Impedance

全部床義歯床下組織の負担圧分布に関する基礎的研究 --- 第1報 微少静電容量型負担圧測定システムの開発