Yuki Iwawaki, Takaharu Goto, Takahiro Kishimoto, Takashi Matsuda, Keiko Fujimoto, Kan Nagao, Kenji Yoshimura, Teppei Tajikara, Yoshiyuki Eshita, Yoshitaka Yano and Tetsuo Ichikawa : Efficacy evaluation with stratified randomized controlled study of foam dentifrice containing isodecyl galactosides in older adults, Journal of Oral Science, 67, 3, 134-139, 2025.
(要約)
Oral hygiene is mainly maintained by mechanical plaque removal, but this is often inadequate in older adults. Isodecyl galactosides (ID-Gal) inhibits bacterial co-aggregation and could promote the maintenance and improvement of oral hygiene. In this study, the efficacy of ID-Gal-containing foam dentifrice in oral hygiene among older adults was evaluated. Fifty-six subjects aged 65 years or older visited Tokushima University Hospital and were randomly assigned to interventions using ID-Gal-containing foam dentifrice applied to the dorsum of the tongue, or to controls using their usual dentifrice. Microbiological and clinical oral health parameters were evaluated before, and at 1 and 2 months after the intervention. The intervention group showed significant decreases in black pigment-producing bacteria on the dorsum of the tongue, Fusobacterium, and total bacterial counts on the mucosa below the denture base after 1 month. Additionally, the intervention group showed significant decrease in the Winkle Tongue Coating Index (WTCI) after 2 months. ID-Gal-containing foam dentifrice decreased the number of bacteria by suppressing plaque formation and contributed to a reduction in the number of bacteria on the tongue and the WTCI. Collectively, these results suggest that ID-Gal-containing foam dentifrice is effective in maintaining and improving oral hygiene.
(キーワード)
Humans / Dentifrices / Female / Male / Aged / Oral Hygiene / Dental Plaque / Treatment Outcome / Aged, 80 and over / Tongue
Yuri Oku, Hideki Suito, Keiko Fujimoto, Tetsuo Ichikawa and Kan Nagao : Relationship between vertical hyoid bone position and swallowing function in older adults., Journal of Oral Science, 67, 2, 91-95, 2025.
(要約)
JOF may affect swallowing function in older males with lowered hyoid bone position.
Hideki Suito, Hozumi Yoshihara, Naoki Maeda, Ryosuke Kasai, Tadashi Inoue, Masafumi Amano, Yuri Oku, Keiko Fujimoto and Kan Nagao : Evaluation of the effect of reducing metal artifacts in multi-detector CT imaging of zirconia and titanium implants, Oral Radiology, 41, 3, 421-429, 2025.
(要約)
Zirconia oral implants produce larger artifacts on computed tomography (CT) compared to titanium oral implants. This study aimed to compare the effectiveness of metal artifact reduction (MAR) software and dual-energy (DE) methods, which are used in multi-detector CT (MDCT) to reduce the artifacts produced by titanium and zirconia oral implants. Oral implants were placed in the lower right second premolar and second molar regions of an acrylic mandible model and evaluated using MDCT. For MAR, Single Energy Metal Artifact Reaction (SEMAR) images were obtained, and for DE, images were obtained at 135 keV. The evaluation was based on 21 regions of interest (ROIs) with sides of 2.8 mm, set at 15, 25, and 35 mm from the center (the lower-right first premolar), with 65°, 90°, 115°, and 145° angles set on the buccal and lingual sides. The evaluation was based on an Artifact Index (AI). The lingual aspect of the AI tended to be larger compared to the buccal aspect, regardless of the image-processing method. In addition, the SEMAR method tended to have a greater artifact reduction effect than the DE method. The distortion of the mandibular model and occurrence of new artifacts were confirmed using SEMAR. SEMAR had higher artifact reduction effects on metal artifacts than the DE method. Although SEMAR and dual-energy methods can effectively reduce metal artifacts, they also cause false images and areas that cannot be observed. Therefore, diagnostic and treatment planning, including imaging, is essential before artifact reduction processing.
Hideki Suito, Keiko Fujimoto, Takaharu Goto, Kan Nagao, Hidehiko Hosoki and Tetsuo Ichikawa : Effective use of an extraoral vacuum in preventing the dispersal of particulate matter from metal dental materials., Journal of Occupational Health, 65, 1, e12412, 2023.
(要約)
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.
Kan Nagao, Keiko Fujimoto, Hideki Suito, Takaharu Goto, Yuichi Ishida, Megumi Watanabe and Tetsuo Ichikawa : Effect of Palatal Augmentation Prosthesis on Speech and Swallowing in Tongue Dysfunction:A Literature Review, Journal of Oral Health and Biosciences, 35, 2, 39-46, 2023.
(要約)
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.
(キーワード)
Palatal augmentation prosthesis / Tongue dysfunction / Literature review
Yoshihiro Tagami, Keiko Fujimoto, Takaharu Goto, Hideki Suito, Kan Nagao and Tetsuo Ichikawa : Can Measurement of Ultrasonic Echo Intensity Predict Physical Frailty in Older Adults?, Diagnostics, 13, 4, 675, 2023.
(要約)
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.
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.
Yoshihiro Tagami, Keiko Fujimoto, Takaharu Goto, Hideki Suito, Kan Nagao and Tetsuo Ichikawa : Measurement of ultrasonic echo intensity predicts the mass and strength of the tongue muscles in the elderly, Journal of Oral Science, 64, 1, 44-48, 2022.
(要約)
The purpose of this study was to investigate the relationship between the echo intensity (EI) on ultrasound images of the tongue, tongue thickness, and tongue pressure to examine the effectiveness of EI measurement for assessing the tongue function. A total of 100 elderly outpatients were enrolled. Tongue thickness and EI were measured using ultrasonography. The distance from mylohyoid muscle surface to dorsal surface of the tongue was measured for tongue thickness. Subsequently, this area was vertically divided into four areas: top of tongue dorsal side (DT), bottom of tongue dorsal side (DB), top of basal tongue side (BT), and bottom of basal tongue side (BB), and the EI was measured in each area. The mean EIs of DT and DB were lower than those of BT and BB. In the three areas apart from BB, the EI decreased with an increase in tongue thickness. In particular, a significant correlation between the EI in DB and tongue thickness was found. In all areas, the EI decreased with an increase in tongue pressure. The results of this study suggested that the measurement of EI could be an important indicator for assessing the tongue function in the elderly.
<p><b>Purpose </b>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.</p><p><b>Methods </b>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.</p><p><b>Results </b>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.</p><p><b>Conclusions </b>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.</p>
Keiko Fujimoto, Hideki Suito, Kan Nagao and Tetsuo Ichikawa : Does Masticatory Ability Contribute to Nutritional Status in Older Individuals?, International Journal of Environmental Research and Public Health, 17, 20, 2020.
(要約)
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.
(キーワード)
Aged / Female / Humans / Male / Mastication / Nutritional Status / Pressure / Quality of Life / Tongue
Y Nishi, T Nomura, M Murakami, Y Kawai, M Nishimura, H Kondo, Y Ito, A Tsuboi, G Hong, S Kimoto, A Gunji, A Suzuki, G Ohwada, S Minakuchi, Y Sato, T Suzuki, K Kimoto, N Hoshi, M Saita, Y Yoneyama, Y Sato, M Morokuma, J Okazaki, T Maeda, K Nakai, Tetsuo Ichikawa, Kan Nagao, Keiko Fujimoto, H Murata, T Kurogi, K Yoshida, T Hosoi and T Hamada : Effect of denture adhesives on oral moisture: A multicenter randomized controlled trial, Journal of Prosthodontic Research, 64, 3, 281-288, 2020.
(要約)
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.
G Ohwada, S Minakuchi, Yuji Sato, A Tsuboi, Tetsuo Ichikawa, Kan Nagao and Keiko Fujimoto : Subjective Evaluation of Denture Adhesives: A Multicenter Randomized Controlled Trial., JDR Clinical and Translational Research, 5, 1, 50-61, 2019.
(要約)
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.
Minakuchi Shinsuke, Tsuga Kazuhiro, Ikebe Kazunori, Ueda Takayuki, Tamura Fumiyo, Kan Nagao, Furuya Junichi, Matsuo Koichiro, Yamamoto Ken, Kanazawa Manabu, Watanabe Yutaka, Hirano Hirohiko, Kikutani Takeshi and Sakurai Kaoru : Oral Hypofunction in the Older Population -Position Paper of the Japanese Society of Gerodontology in 2016, Gerodontology, 35, 4, 317-324, 2018.
(要約)
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.
(キーワード)
Aged / Bite Force / Deglutition Disorders / Dental Care for Aged / Geriatric Dentistry / Humans / Japan / Mastication / Oral Health / Oral Hygiene / Societies, Dental / Xerostomia
Takuro Baba, Takaharu Goto, Keiko Fujimoto, Hideki Suito, Kazutomo Yagi, Kan Nagao and Tetsuo Ichikawa : Geniohyoid muscle affects directly masticatory function: Evaluation using a decision tree analysis, The International Journal of Prosthodontics, 31, 6, 569-572, 2018.
(要約)
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.
(キーワード)
Body Mass Index / Decision Trees / 女性 (female) / Humans / 男性 (male) / Mastication / Middle Aged / Muscle Strength / Neck Muscles / Pharyngeal Muscles / Pressure / Range of Motion, Articular
Yoshihito Naitou, Hiromichi Yumoto, K Hs Kumar, Takashi Matsuo, Katsuhiko Hirota, Yoichiro Miyake, Kan Nagao, Yoritoki Tomotake, R Jimbo and Tetsuo Ichikawa : Antifungal and Mechanical Properties of Tissue Conditioner Containing Plant-Derived Component, --- An In Vitro Study ---, Journal of Prosthodontics, 27, 7, 665-669, 2018.
(要約)
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.
Keiko Fujimoto, Tsuyoshi Honda, Hideki Suito, Kan Nagao and Tetsuo Ichikawa : Tongue thickness and its clinical significance, Journal of Oral Health and Biosciences, 31, 1, 32-38, 2018.
Takuo Kuboki, Tetsuo Ichikawa, Kazuyoshi Baba, Masanori Fujisawa, Hironobu Sato, Hideki Aita, Shigeto Koyama, Masayuki Hideshima, Yuji Sato, Hiroyuki Wake, Aya Kimura-Ono, Kan Nagao, Yorika Kodaira, Katsushi Tamaki, Shinsuke Sadamori, Kazuhiro Tsuga, Yasuhiro Nishi, Takashi Sawase, Hisashi Koshino, Shinichi Masumi, Kaoru Sakurai, Kanji Ishibashi, Takashi Ohyama, Yasumasa Akagawa, Toshihiro Hirai, Keiichi Sasaki, Kiyoshi Koyano, Hirofumi Yatani and Hideo Matsumura : A multi-centered epidemiological study evaluating the validity of the treatment difficulty indices developed by the Japan Prosthodontic Society, Journal of Prosthodontic Research, 62, 2, 162-170, 2018.
(要約)
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.
(キーワード)
Cohort Studies / Forecasting / Humans / Japan / Mouth, Edentulous / Oral Health / Process Assessment (Health Care) / Prosthodontics / Quality of Life / Societies, Dental / Time Factors
Sachie Wada, Takaharu Goto, Keiko Fujimoto, Megumi Watanabe, Kan Nagao, Atsuko Nakamichi and Tetsuo Ichikawa : Changes in food bolus texture during mastication, Journal of Texture Studies, 48, 2, 171-177, 2017.
(要約)
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.
(キーワード)
food bolus texture / mastication / number of chews / oral processing
Yoshizo Matsuka, Yoshiyuki Hagiwara, Katsushi Tamaki, Hisahiro Takeuchi, Masanori Fujisawa, Takahiro Ono, Yoshihiro Tsukiyama, Kan Nagao, Kazuhiro Tsuga, Hideki Aita, Hisatomo Kondo, Kenji Fueki, Hiroaki Tsukasaki, Keisuke Nishigawa, Shogo Ozawa, Rika Kuwatsuru, Hajime Minakuchi, Toshimitsu Iinuma, Takashi Matsuura, Kanji Ishibashi, Shigehisa Fujii, Toshihiro Hirai, Keiichi Sasaki, Hirofumi Yatani, Yoshimasa Igarashi, Yuji Sato, Tetsuo Ichikawa, Tetsuo Yamamori, Takuo Kuboki, Kazuyoshi Baba, Kiyoshi Koyano, Hironobu Sato and Matsumura Hideo : Reliability and validity of the patient disability-oriented diagnostic nomenclature system for prosthetic dentistry, Journal of Prosthodontic Research, 61, 1, 20-33, 2017.
(要約)
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.
Tsuyoshi Honda, Takuro Baba, Keiko Fujimoto, Takaharu Goto, Kan Nagao, Masafumi Harada, Eiichi Honda and Tetsuo Ichikawa : Characterization of Swallowing Sound: Preliminary Investigation of Normal Subjects, PLoS ONE, 11, 12, e0168187, 2016.
(要約)
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.
(キーワード)
Acoustics / Adult / Deglutition / Deglutition Disorders / Epiglottis / Esophagus / Female / Fluoroscopy / Healthy Volunteers / Humans / Hyoid Bone / Iopamidol / Larynx / Male / Pharynx / Posture / Sound / Video Recording / Water / Young Adult
Takaharu Goto, Nobuaki Higaki, Kazutomo Yagi, Yuichi Ishida, Megumi Watanabe, Kan Nagao and Tetsuo Ichikawa : An innovative masticatory efficiency test using odor intensity in the mouth as a target marker: a feasibility study, Journal of Oral Rehabilitation, 43, 12, 883-888, 2016.
(要約)
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.
Suguru Kimoto, Yasuhiko Kawai, Atsuko Gunji, Hisatomo Kondo, Taro Nomura, Tomohiko Murakami, Akito Tsuboi, Guang Hong, Shunsuke Minakuchi, Yusuke Sato, Gaku Ohwada, Tetsuya Suzuki, Katsuhiko Kimoto, Noriyuki Hoshi, Makiko Saita, Yoshikazu Yoneyama, Yohei Sato, Masakazu Morokuma, Joji Okazaki, Takeshi Maeda, Kenichiro Nakai, Tetsuo Ichikawa, Kan Nagao, Keiko Fujimoto, Hiroshi Murata, Tadafumi Kurogi, Kazuhiro Yoshida, Masahiro Nishimura, Yasuhiro Nishi, Mamoru Murakami, Toshio Hosoi and Taizo Hamada : Study protocol for a multi-center, randomized controlled trial to develop Japanese denture adhesive guidelines for patients with complete dentures: The Denture Adhesive Guideline trial: Study protocol for a randomized controlled trial, Trials, 17, 1, 506, 2016.
(要約)
Denture adhesives, characterized as medical products in 1935 by the American Dental Association, have been considered useful adjuncts for improving denture retention and stability. However, many dentists in Japan are hesitant to acknowledge denture adhesives in daily practice because of the stereotype that dentures should be inherently stable, without the aid of adhesives. The aim of this study is to verify the efficacy of denture adhesives to establish guidelines for Japanese users. The null hypothesis is that the application of denture adhesives, including the cream and powder types, or a control (isotonic sodium chloride solution) would not produce different outcomes nor would they differentially improve the set outcomes between baseline and day 4 post-application. This ten-center, randomized controlled trial with parallel groups is ongoing. Three hundred edentulous patients with complete dentures will be allocated to three groups (cream-type adhesive, powder-type adhesive, and control groups). The participants will wear their dentures with the denture adhesive for 4 days, including during eight meals (three breakfasts, two lunches, and three dinners). The baseline measurements and final measurements for the denture adhesives will be performed on the first day and after breakfast on the fourth day. The primary outcome is a general satisfaction rating for the denture. The secondary outcomes are denture satisfaction ratings for various denture functions, occlusal bite force, resistance to dislodgement, masticatory performance, perceived chewing ability, and oral health-related quality of life. Between-subjects comparisons among the three groups and within-subjects comparisons of the pre- and post-intervention measurements will be performed. Furthermore, a multiple regression analysis will be performed. The main analyses will be based on the intention-to-treat principle. A sample size of 100 subjects per group, including an assumed dropout rate of 10 %, will be required to achieve 80 % power with a 5 % alpha level. This randomized clinical trial will provide information about denture adhesives to complete denture wearers, prosthodontic educators, and dentists in Japan. We believe this new evidence on denture adhesive use from Japan will aid dentists in their daily practice even in other countries. ClinicalTrials.gov NCT01712802 . Registered on 17 October 2012.
(キーワード)
全部床義歯 (complete dentures) / Denture adhesive / Edentulism / Masticatory performance / Occlusal bite force / Oral health-related quality of life / Retentive force
Yuichi Ishida, Kumer Kiran, Takaharu Goto, Megumi Watanabe, Wigianto Rudi, Kan Nagao and Tetsuo Ichikawa : Magnet-retained two-mini-implant overdenture: Clinical and mechanical consideration., Dentistry Journal, 4, 4, 35, 2016.
(要約)
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.
Keiko Fujimoto, Norikazu Minami, Takaharu Goto, Yuichi Ishida, Megumi Watanabe, Kan Nagao and Tetsuo Ichikawa : Hardness, cohesiveness, and adhesiveness of oral moisturizers and denture adhesives: selection criteria for denture wearers., Dentistry Journal, 4, 4, 34, 2016.
(要約)
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.
Takashi Matsuda, Takaharu Goto, Kosuke Kurahashi, Toshiya Kashiwabara, Megumi Watanabe, Yoritoki Tomotake, Kan Nagao and Tetsuo Ichikawa : Digital assessment of preliminary impression accuracy for edentulous jaws: Comparisons of 3-dimensional surfaces between study and working casts, Journal of Prosthodontic Research, 60, 3, 206-212, 2016.
(要約)
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.
Tsuyoshi Honda, Keiko Fujimoto, Takuro Baba, Kan Nagao, Akira Takahashi and Tetsuo Ichikawa : Swallowing sound waveform and its clinical significance: Evaluation using ultrasonography, Journal of Oral Health and Biosciences, 28, 1, 21-27, 2015.
(要約)
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.
Takaharu Goto, Atsuko Nakamichi, Megumi Watanabe, Kan Nagao, Miwa Matsuyama and Tetsuo Ichikawa : Influence of food volume per mouthful on chewing and bolus properties, Physiology & Behavior, 141, 58-62, 2015.
(要約)
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.
(キーワード)
Eating / Energy Intake / Feeding Behavior / Female / Food / Humans / Mastication / Young Adult
Takaharu Goto, Kan Nagao, Yuichi Ishida, Yoritoki Tomotake and Tetsuo Ichikawa : Influence of female attachment installation load on movement and resultant forces in implant overdentures, Journal of Prosthodontics, 24, 2, 156-163, 2015.
(要約)
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.
Kan Nagao, Takaharu Goto, Yuichi Ishida, Tetsuo Ichikawa, M Hideshima, H Koshino, K Hoshiai and Y Umekawa : 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, 22, 2, 43-46, 2013.
37.
Takaharu Goto, Yuichi Ishida, Kan Nagao and Tetsuo Ichikawa : Long-term follow-up case reports on the use of magnetic attachment as intracoronal/extracoronal attachments, The Journal of the Japanese Sociaty of Magnetic Applications in Dentistry, 22, 2, 12-14, 2013.
Takaharu Goto, Hidenobu Nishinaka, Toshiya Kashiwabara, Kan Nagao and Tetsuo Ichikawa : Main occluding area in partially edentulous patients: changes before and after implant treatment, Journal of Oral Rehabilitation, 39, 9, 677-683, 2012.
(要約)
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.
Seiko Hongama, Kan Nagao, Sachie Toko, Kyuma Tanida, Masatake Akutagawa, Yohsuke Kinouchi and Tetsuo Ichikawa : MI sensor-aided screening system for assessing swallowing dysfunction: Application to the repetitive saliva-swallowing test, Journal of Prosthodontic Research, 56, 1, 53-57, 2012.
(要約)
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.
(キーワード)
Adult / Aged / Aged, 80 and over / Deglutition / Deglutition Disorders / Electric Impedance / Female / Humans / Magnets / Male / Middle Aged / Prosthodontics / Saliva / Young Adult
Tetsuo Ichikawa, Kan Nagao and Takaharu Goto : Alternative Decision Making Considerations in Prosthodontics, The International Journal of Prosthodontics, 25, 3, 260-261, 2012.
Chen Rong Jian, Yoritoki Tomotake, Megumi Watanabe, Yuichi Ishida, Kan Nagao and Tetsuo Ichikawa : Telescopic Magnetic Attachment for Implant-Supported Denture: Evaluation of Splint Effect, The International Journal of Oral & Maxillofacial Implants, 26, 3, 657-664, 2011.
(要約)
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.
Toshiya Kashiwabara, Takaharu Goto, Yutaka Sato, Yoritoki Tomotake, Kan Nagao and Tetsuo Ichikawa : A new method to prevent the corrosion of dental materials, during disinfection using functional water: Sacrificial protection, Journal of Prosthodontic Research, 54, 3, 147-149, 2010.
(要約)
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.
Wei Hau, Yoritoki Tomotake, Kan Nagao and Tetsuo Ichikawa : Implant prostheses and adjacent tooth migration: preliminary retrospective survey using 3-dimensional occlusal analysis., The International Journal of Prosthodontics, 21, 4, 302-304, 2008.
(要約)
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.
(キーワード)
Bite Force / Dental Prosthesis, Implant-Supported / Dental Stress Analysis / Humans / Malocclusion / Mesial Movement of Teeth / Retrospective Studies
(文献検索サイトへのリンク)
● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 18717086
Toshiya Kashiwabara, Yuka Yoshijima, Seiko Hongama, Kan Nagao, Katsuhiko Hirota and Tetsuo Ichikawa : Denture plaque microflora in geriatric inpatients and maxillary defect patients, Prosthodontic Research & Practice, 6, 3, 153-158, 2007.
(要約)
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.
Chen Jianrong, Kan Nagao, Yoritoki Tomotake and Tetsuo Ichikawa : Influence of a Vent Hole on the Retentive Force of a Cement-retained Superstructure before/after Thermocycling, Prosthodontic Research & Practice, 5, 3, 157-160, 2006.
(要約)
<B>Purpose:</B> 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.<BR><B>Methods:</B> 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<BR><B>Results:</B> 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.<BR><B>Conclusion:</B> 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.
(キーワード)
retentive force / cement-retained superstructure / vent hole / thermocycling
Hua Wei, Yoritoki Tomotake, Kan Nagao, Takafumi Ohguri, Daisuke Nagao and Tetsuo Ichikawa : In vitro Study of Stress Distribution on Additional Posterior Mandibular Implants, Prosthodontic Research & Practice, 3, 1, 84-91, 2004.
(要約)
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.
(キーワード)
stress distribution / splinting / posterior installation of implant / mandibular distortion
Kan Nagao, Naoki Kitaoka, Fumiaki Kawano, Junji Komoda and Tetsuo Ichikawa : Influence of Changes in Occlusal Vertical Dimension on Tongue Pressure to Palate during Swallowing, Prosthodontic Research & Practice, 1, 1, 16-23, 2002.
(要約)
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.
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 <I>Candida</I> spp.<BR>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, <I>Candida</I> spp., <I>Pseudomonas aeruginosa, Escherichia coli</I> and coliforms, and MRSA. Isolated <I>Candida</I> spp. were measured for drug susceptibility.<BR>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 <I>Candida</I> spp. All strains of <I>Candida</I> spp. appeared to be susceptible to amphotericin B. Some strains of <I>C. glabrata, C</I>.tropicalis, and <I>C. krusei</I> appeared to be less susceptible to fluconazole. Fluconazole-resistant <I>C. albicans</I> was not isolated.<BR>Conclusions: Denture plaque strongly influences the pharyngeal microflora in the elderly.
Fumiaki Kawano, Kan Nagao, Sanshiro Inoue and Naoyuki Matsumoto : Influence of the buccolingual position of artificial posterior teeth on the pressure distribution on the supporting tissue under a complete denture, Journal of Oral Rehabilitation, 23, 7, 456-463, 1996.
(要約)
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.
soft denture liner / lining method / acceleration / rising time / free drop test
66.
Sanshiro Inoue, Fumiaki Kawano, Kan Nagao and Naoyuki Matsumoto : An In Vitro Study of the Influence of Occlusal Scheme on the Pressure Distribution of Complete Denture Supporting Tissue, The International Journal of Prosthodontics, 9, 2, 179-187, 1996.
(要約)
This study compared lingualized occlusion and completely balanced occlusion using a simulation device. Sixteen pressure transducers were placed in the simulated residual ridge area supporting the test dentures. Lingualized occlusion was found to transfer stresses from the occluding side to the opposite, nonworking side to stabilize the mandibular denture.
viscoelastic finite element analysis / tooth arrangement / stress distribution / supporting structure
74.
Fumiaki Kawano, Nozomu Tada, Kan Nagao and Naoyuki Matsumoto : The influence of soft lining materials on pressure distribution, The Journal of Prosthetic Dentistry, 65, 4, 567-576, 1991.
stress relaxation / supporting structure / viscoelastic finite element method
77.
Fumiaki Kawano, Kenzo Asaoka, Kan Nagao and Naoyuki Matsumoto : Effect of viscoelastic deformation of soft tissue on stresses in the structures under complete denture, Dental Materials Journal, 9, 1, 70-79, 1990.
(キーワード)
Soft tissue / Finite element stress analysis / Viscoelastic deformation
impedance grid pressure sensor / pressure distribution / simulator / supporting bone
総説・解説:
1.
Keiko Fujimoto, Hideki Suito, Kan Nagao and Tetsuo Ichikawa : Validity of Quantitative and Qualitative Assessments of Skeletal Muscles in the Lower Extremities Using Ultrasound Imaging: A Literature Review, Journal of Oral Health and Biosciences, 36, 2, 30-35, 2024.
(要約)
Purpose: To explore the use of ultrasound (US) for quantitative and qualitative assessment of muscles (especially the tongue) in dentistry, we performed investigations using muscles of the lower extremities. These muscles are often used to assess skeletal muscles in general. We aimed to determine whether there was a correlation between quantitative and qualitative assessments of lower extremity muscles using diagnostic US and computed tomography (CT) scans in adults.<br> Procedure: We conducted a search for English articles published in PubMed and Scopus from its inception up to October 18, 2022. We used a combination of the keywords ``muscle,'' ``ultrasonography,'' and ``computed tomography'' for the search. Additionally, we manually searched through relevant journals and search engines.<br> Main findings: After applying the inclusion criteria, we ultimately selected seven studies for inclusion in this review. These seven studies focused on muscle mass and involved ultrasonographic evaluations of muscle thickness and cross-sectional area as well as CT evaluations of muscle volume and cross-sectional area. Two studies also evaluated muscle quality using echo intensity (EI) for US assessment and CT values for CT assessment. In three of the seven studies, there was a significant correlation between the US and CT results. Three studies also determined an intraclass correlation coefficient (≥0.8 in all three) to determine the correlation between CT and US. In both studies that additionally assessed muscle quality, a strong correlation was observed between CT and US measurements.<br> Conclusion: Our results suggest that US can be used to perform high quality assessments of lower extremity muscles and muscle mass in healthy individuals and patients with mild or moderate disease. In the future, high quality research on the tongue is needed for application to the field of dentistry.
(キーワード)
ultrasonography / computed tomography / muscle mass / muscle quality
後藤 崇晴, 岩脇 有軌, 渡邉 恵, 永尾 寛, 市川 哲雄 : 補綴装置による個人認証システムに関する文献的考察, Journal of Oral Health and Biosciences, 27, 2, 21-27, 2015年2月.
(要約)
In disasters such as hydraulic bore, earthquakes and fire, the oral structure including the dental prostheses can provide identifying information. Over the years, many different personal identification system of dental prostheses have been reported. This present study analyzes the published literature offering the description of the personal identification system of dental prostheses.Two databases, "PubMed" and "Japana Centra Revuo Medicina" were searched to retrieve research papers referred to the personal identification system of dental prostheses. Twenty four papers were selected from the database with the criteria, and they were reviewed. This literature search showed that the personal identifications in three kinds of dental prostheses: removable denture, crown and implant were reported; and more papers on removable dentures were extracted compared to the crown and implant, however there is no high quality paper indicating that the structured methods for personal identification of dental prostheses is effective. A new method and common write format for personal identification are required to improve the present problems, and our systems using fluorescent material and ultraviolet light and femtosecond pulse laser-oriented recording system would be effective.
In case of making complete dentures, we have to consider not only denture stability but also the restoration of aesthetics and function such as mastication and speech. However these are contradictory theoretically from the point of view of denture stability, and it is very difficult to satisfy both requirements in the case of a patient who has poor upper and lower alveolar ridges. We investigated the effect of artificial posterior teeth form and occlusal scheme on the distribution of pressure on supporting structures under complete dentures during mastication with upper and lower edentulous simulators. In this report, a guideline for the selection of occlusal scheme for complete dentures, based on our previous investigations, is described. The occlusal scheme remarkably affected the distribution of pressure under simulated complete dentures, as shown by comparing the distribution of pressure using two different occlusal schemes:fully balanced occlusion and lingualized occlusion. However other factors such as posterior teeth form and position affect the distribution of pressure as well, and are related to each other. Therefore, not only occlusal scheme but also posterior artificial teeth form has to be considered, and the form of posterior teeth should be carefully and comprehensively decided when making complete dentures.
selection of the posterior teeth / pressure distribution / complete denture / occlusal scheme / occlusal form
国際会議:
1.
Takaharu Goto, Tsukasa Hihara, Keiko Fujimoto, Kan Nagao and Tetsuo Ichikawa : Sex difference of clinical cascade from oral hypofunction to physical frailty, The 7th Biennial Joint Congress of KAP-CPS-JPS, Mar. 2019.
2.
Takaharu Goto, Tsukasa Hihara, Tagami Yoshihiro, Yuki Iwawaki, Kan Nagao and Tetsuo Ichikawa : Investigation with questionnaires on symptoms of physical frailty and eating behaviors, 11th Biennial Congress of Asian Academy of Prosthodontics, Kuala Lumpur, Malaysia, Sep. 2018.
3.
Tetsuo Ichikawa, Takaharu Goto, Tsukasa Hihara, Tagami Yoshihiro and Kan Nagao : A quantitative evaluation of oral frailty-physical frailty relationship model based on covariance structure analysis, 11th Biennial Congress of Asian Academy of Prosthodontics, Kuala Lumpur, Malaysia, Sep. 2018.
4.
Takaharu Goto, Hihara Tsukasa, Kishimoto Takahiro, Takashi Matsuda, Yuki Iwawaki, Kan Nagao and Tetsuo Ichikawa : Investigation with questionnaires on symptoms of oral frailty and eating behaviors: Importance of chewing, Biennial Joint Congress of JPS-CPS-KAP, Wenzhou, China, Oct. 2017.
5.
Takashi Matsuda, Kurahashi Kosuke, Ishida Yuichi, Takaharu Goto, Kan Nagao and Tetsuo Ichikawa : Part-digitizing system for complete denture fabrication using digital impression and specialized CAD/CAM tray, The 17th Biennial Meeting of International College of Prosthodontists, Santiago, Chile, Sep. 2017.
6.
Takaharu Goto, Yoritoki Tomotake, Yuichi Ishida, Nobuaki Higaki, Kan Nagao and Tetsuo Ichikawa : Functional Significance of the Main Occluding Area for Partially Edentulous, 16th Biennial Meeting of International College of Prosthodontists, Sep. 2015.
7.
Nobuaki Higaki, Takaharu Goto, Yuki Iwawaki, Kan Nagao and Tetsuo Ichikawa : Brain Function on Modulation of Occlusal Force and Sensory Integration, 16th Biennial Meeting of International College of Prosthodontists, Sep. 2015.
8.
Shiori Nakamura, Nobuaki Higaki, Takaharu Goto, Kan Nagao and Tetsuo Ichikawa : Effect analysis of oral stimulation to prevent dementia focusing on the individual sensibility, 16th Biennial Meeting of International College of Prosthodontists, Sep. 2015.
9.
Takashi Matsuda, Takaharu Goto, Toshiya Kashiwabara, Kan Nagao and Tetsuo Ichikawa : Possibility of Complete Denture Fabrication using Digital Technology: the possibility of Contactless Digital Preliminary Impression, The 3rd ASEAN plus and TOKUSHIMA Joint International Conference on ``Strategic Achievement of Oral Sciences and Promotion of Quality of Life'', Makassar, Dec. 2014.
10.
Nobuaki Higaki, Takaharu Goto, Yuichi Ishida, Kan Nagao and Tetsuo Ichikawa : Effects of vibratory and gustatory stimulations on cerebral blood flows, The 3rd ASEAN plus and TOKUSHIMA Joint International Conference ``Strategic Achievement of Oral Sciences and Promotion of Quality of Life'', Makassar, Dec. 2014.
11.
Takaharu Goto, Yoritoki Tomotake, Yuichi Ishida, Nobuaki Higaki, Kan Nagao and Tetsuo Ichikawa : Clinical significance of the main occluding in prosthodontic treatment, The 3rd ASEAN plus and TOKUSHIMA Joint International Conference on ``Strategic Achievement of Oral Sciences and Promotion of Quality of Life'', Makassar, Dec. 2014.
12.
Tsuyoshi Honda, Keiko Fujimoto, Takuro Baba, Seiko Hongama, Kan Nagao and Tetsuo Ichikawa : Elucidation of swallowing Sound Production Mechanism Using Ultrasonography, Indonesian and Japan Prosthodontic Society JOINT MEETING, Bali, Nov. 2014.
13.
Takashi Matsuda, Tetsuo Ichikawa, Takaharu Goto, Toshiya Kashiwabara and Kan Nagao : Digital preliminary impression for complete denture fabrication, Indonesia Japan Prosthodontic Society JOINT MEETING, Bali, Oct. 2014.
14.
Kan Nagao, Takaharu Goto and Tetsuo Ichikawa : Which is better for complete denture wearers, fully balanced occlusion or lingualized occlusion, Indonesian and Japan Prosthodontic Society JOINT MEETING, Bali, Oct. 2014.
15.
Takaharu Goto, Yuichi Ishida, Megumi Watanabe, Yoritoki Tomotake, Kan Nagao and Tetsuo Ichikawa : Location of the main occluding area after implant treatment, 38th Annual Conference of The European Prosthodontic Association, Istanbul, Sep. 2014.
16.
Sachie Toko, Tetsuo Ichikawa, Atsuko Nakamichi, Tsuyoshi Honda and Kan Nagao : Properties of Food Bolus for Assessing Quality of Mastication, 38th Annual Conference of The European Prosthodontic Association, Istanbul, Sep. 2014.
17.
Takaharu Goto, Atsuko Nakamichi, Sachie Toko, Tsuyoshi Honda, Kan Nagao and Tetsuo Ichikawa : Assessments of Quality of mastication: Relationship between overall eating behavior and mastication, The 15th Biennial Meeting of International College of prosthodontics, Turin, Sep. 2013.
18.
Nobuaki Higaki, Takaharu Goto, Yuki Iwawaki, Kan Nagao and Tetsuo Ichikawa : Efficiency of oral stimulations on brain function activities: Evaluations using wearable near-infrared spectroscopy, The 15th Biennial Meeting of International College of prosthodontics, Turin, Sep. 2013.
19.
Takaharu Goto, Nobuaki Higaki, Yoritoki Tomotake, Kan Nagao and Tetsuo Ichikawa : Sensation of osseointegrated implants: literature review and new neurophysiological approach, ASEAN plus and TOKUSHIMA Joint International Conference"Strategic Achievement of Oral Sciences and Promotion of Quality of Life", Dec. 2012.
20.
Takashi Matsuda, Takaharu Goto, Yuichi Ishida, Toshiya Kashiwabara, Kan Nagao and Tetsuo Ichikawa : A Trial of Complete Denture Fabrication using Digital Technology: in vitro Evaluation of digital impression, ASEAN plus and TOKUSHIMA Joint International Conference"Strategic Achievement of Oral Sciences and Promotion of Quality of Life", Yogyakarta, Dec. 2012.
21.
Sachie Toko, Hitoshi Higa, Tsuyoshi Honda, Seiko Hongama, Kan Nagao and Tetsuo Ichikawa : Changes in the physical properties of food bolus and mandibular movement during mastication, ASEAN plus and TOKUSHIMA Joint International Conference on "Strategic Achievement of Oral Sciences and Promotion of Quality of Life", Yogyakarta, Dec. 2012.
22.
Takaharu Goto, Takashi Matsuda, Yuichi Ishida, Toshiya Kashiwabara, Kan Nagao and Tetsuo Ichikawa : Digital dentistry in complete denture fabrication, --- Feasibility study ---, International Symposium on Oral Health Education and Research, Balikpapan, Dec. 2011.
23.
Yuki Iwawaki, Yoshihito Naitou, Li Jing, Kan Nagao and Tetsuo Ichikawa : The long-term change in properties of the anti-microbiological tissue conditioner containing Juncus powder, The 7th Biennial Meeting of AAP, Shanghai, Oct. 2011.
24.
Takaharu Goto, Kan Nagao, Yuichi Ishida, Yoritoki Tomotake and Tetsuo Ichikawa : Influence of Attachments On Load Transfer in Implant Overdentures: Effect Of Denture Rigidity, 14th Meeting of International College of Prosthodontists, Hawaii, Sep. 2011.
25.
Takaharu Goto, Kan Nagao, Yuichi Ishida, Yoshihito Naitou, Yoritoki Tomotake and Tetsuo Ichikawa : Observation of the Main ccluding Area with Partually bentate, changes before/after Prosthetic Treatments., 6th Scientific Meeting Asian Academy of Osseointegration, Seoul, Nov. 2010.
26.
Takaharu Goto, Kan Nagao, Yuichi Ishida, Yoshihito Naitou, Megumi Watanabe, Yoritoki Tomotake and Tetsuo Ichikawa : Influence of Attachments on Load Transfer in Implant Overdentures, 19th Annual Scientific Meeting European Assocoation for Osseintegration, Glasgow, Oct. 2010.
27.
Fumiaki Kawano, Kan Nagao, Takao Hanawa, Masayuki Kon, Kenzo Asaoka, A Koran and Naoyuki Matsumoto : Shock-absorbing behavior of soft liners as influenced by accelerated aging, Journal of Dental Research, 75, Spec, 308, San Francisco, Mar. 1996.
28.
Fumiaki Kawano, Kan Nagao, Masayuki Kon, Kenzo Asaoka, Naoyuki Matsumoto and A Koran : Cushioning effect of soft liners as influenced by lining method, Journal of Dental Research, 74, Spec, 487, Singapore, Jun. 1995.
Sapaar Bayarmagnai, Yoshihito Naitou, Takaharu Goto, Kan Nagao and Tetsuo Ichikawa : Loss of retentive force and per,manent deformation of polyethylene terephthalate and polyster clasps retainers, 平成25年度公益社団法人日本補綴歯科学会中国・四国支部学術大会, Sep. 2013.
Sapaar Bayarmagnai, Yoshihito Naitou, Takaharu Goto, Kan Nagao and Tetsuo Ichikawa : Extracellular DNA of Candida albicans and its effect on biofilm formation on denture base materials, 平成24年度 (社)日本補綴歯科学会中国・四国・九州合同学術大会, Sep. 2012.
T Goto, H Nishinaka, Toshiya Kashiwabara, Yoritoki Tomotake, Kan Nagao and Tetsuo Ichikawa : Significance of the Main Occluding Area in Implant Treatment, 社団法人日本補綴歯科学会 第120回記念学術大会, May 2011.