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Objective: To study the biomechanical changes induced by differences in perioral force in patients with missing anterior maxillary teeth at rest via finite element analysis (FEA)., Methods: Using conical beam CT (CBCT) images of a healthy person, models of the complete maxillary anterior dental region (Model A) and maxillary anterior dental region with a missing left maxillary central incisor (Model B) were constructed. The labial and palatine alveolar bone and tooth surface of the bilateral incisor and cusp regions were selected as the application sites, the resting perioral force was applied perpendicular to the tissue surface, and the changes in maxillary stress and displacement after the perioral force was simulated were analyzed., Results: Compared with Model A, the labial alveolar bone in the missing tooth area of Model B shows significant stress concentration under the action of perioral force. This adverse stress is distributed in an inverted V-shape, concentrated at the top of the labial alveolar ridge and gradually decreases toward the root., Conclusion: In the resting state, labial soft tissue exerts adverse stress on the alveolar ridge in areas missing maxillary anterior teeth. This stress may affect alveolar bone healing, causing a reduction in alveolar bone width., Competing Interests: Declarations. Ethics approval and consent to participate: This study was approved by the Ethics Committee of Jinan Stomatological Hospital (Approval Number: JNSKQYY-2021-022) and was conducted in accordance with the 2013 revised version of the Declaration of Helsinki. Informed consent was obtained from the individual participants included in the study. Consent for publication: Not applicable. In this study, there were no details, images, or videos related to an individual person needed to be agreed to publish. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Aim: This study aimed to evaluate the effect of partially edentulous ()PED condition on lung function through spirometry tests and comparison of airflow rates between dentulous and PED subjects., Settings and Design: The study design was a cross-sectional study conducted in the department of prosthodontics., Materials and Methods: Twenty-eight dentulous and 28 PED patients with an age range of 25-50 years were included in the study. Patients with missing more than 3 posterior teeth were considered PED. All have undergone spirometric evaluation., Statistical Analysis Used: Independent t-test was used., Results: In all three spirometric measures (forced vital capacity [FVC], forced expiratory volume in 1 s [FEV1], and peak expiratory flow rate [PEFR]), the PED participants had significantly lower FVC, FEV1 (P = 0.0005), and PEFR (P = 0.032) airflow rates than dentulous participants, and males had higher airflow rates than females., Conclusions: FVC, FEV1, and PEFR airflow rates were lower in PED individuals. The lower airflow rates could suggest the possible tendency to develop chronic obstructive pulmonary disease (COPD)., (Copyright © 2025 The Journal of Indian Prosthodontic Society.)

Objective: Posterior edentulism reduces occlusal support, thus increasing the risk and symptoms of temporomandibular disorder. No previous study has explored its effect on the treatment of temporomandibular disorders. This study aimed to examine the relationship between neck posture, balance, and posterior edentulism in patients with temporomandibular disorder and compare the effectiveness of physical therapy. Methods: In a quasi-experimental controlled trial, 26 patients with temporomandibular disorder were divided into 13 in the partly edentulous group and 13 in the dentate group. Both groups received manual therapy, postural exercises, deep neck flexor stabilization, and Kinesio tapping for 6 weeks. Each participant completed 12 physiotherapy sessions, administered twice weekly, with a minimum interval of 48 hours between sessions. Outcomes were assessed at baseline and after the 6-week program, including pain, mandibular movement, posture, and balance. Results: The physical therapy program significantly improved all measured outcomes ( P < .05). Furthermore, the partially edentulous group showed more remarkable improvement in pain and balance compared to the dentate group ( P < .05). Conclusions: Postural exercises effectively alleviate symptoms in patients with temporomandibular disorder, with more significant improvements observed in the partially edentulous group than in the dentate group., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background and Objectives : Oral rehabilitation seeks to enhance mastication, a vital component of oral function that is compromised by tooth loss. This study aimed to assess the degree of improvement of masticatory performance in partially edentulous patients rehabilitated with removable partial dentures (RPD) or fixed partial dental prosthesis (FPDP). Changes in the occlusal contact area (OCA) and satisfaction with their chewing ability during the adaptation period were also evaluated. Materials and Methods : in total, 34 partially edentulous participants (median age 65.3 years; 56% women) who received an RPD or FPDP were assessed using masticatory performance assay, OCA calculation, and a visual analog scale (VAS). Results : Masticatory performance improved by 20% (range from 17% to 25%, p < 0.05) depending on the edentulism and the rehabilitation types. The OCA improved by 4.7 mm 2 ( p < 0.05) and satisfaction with the masticatory function improved by 9% ( p < 0.05) 3 months after prosthesis insertion. Conclusions : Conventional prostheses benefited partially edentulous individuals, improving masticatory performance by 20%. Treatment also increased the OCA in all types of partial edentulism, except in Kennedy class I patients rehabilitated with RPD. Patients' satisfaction with their chewing ability only increased in Kennedy class III patients rehabilitated with RPD.

Purpose: To evaluate the impact of removable partial dentures (RPDs) on masticatory performance (MP) of partially edentulous subjects., Materials and Methods: Electronic database and hand searches were conducted to explore clinical trials reporting the evidence of the effect of metal- and acrylic-based RPDs on mastication. The validated objective and subjective measures of assessment of mastication were included. The article selection, data extraction, and assessment of risk of bias were conducted by two reviewers independently., Results: Out of 11,200 studies, 1 randomized controlled trial and 23 clinical trials met the inclusion criteria. Positive impact on different parameters of masticatory function after RPD treatment was reported in 14 studies. Subjective evaluation of chewing ability (CA) displayed an improvement in 83.3% of studies, while improvement was evidenced only in 69.5% of studies upon objective evaluation. Most studies reported data on free-end saddles. Of the 13 studies associated with bilateral free-end saddle dentures, 9 studies showed a positive effect on masticatory efficiency. Various factors were found to have an impact on the MP of RPDs., Conclusions: Subjective evaluation displays higher positive impact of RPDs in MP than objective evaluation. Assessment of patients' perspectives is important in clinical decision-making. Multiple factors affect the MP with RPD treatment.

We examined alveolar bone samples in the area of on-bone fixation of a free gingival graft performed during surgery in patients aged 37-55 years with a diagnosis of secondary partial adentia of the upper and lower jaws. Six months after fixation of the graft in the alveolar bone, foci of neoosteogenesis were found in the contact zone. They were characterized by the appearance of appositional lines, cords of basophilic osteoblasts, and growing osteons. An immunohistochemical study revealed an increase in the number of CD44 + , CD29 + , and osteocalcin+ cells in the layer of the outer circumferential lamellae, primary osteons, and the lining of the Haversian canals. TGF-β1 + cells were located in the intertrabecular reticular tissue and wall of microvessels. The results indicate activation of mesenchymal stem cells in the area of localization of the graft and differentiating osteoblasts. The observed osteoinductive effect of free gingival graft is associated with its participation in reorganization in MSC and induction of morphogenetic molecules., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

It has been observed that, in patients affected by temporomandibular disorders (TMDs) and edentulism, a left-right asymmetry in electromyographic (EMG) activity of masseter muscles during clenching and in pupil size at rest (anisocoria) is present. Both are greatly reduced by an orthotic-prosthetic correction. In parallel, the correction significantly improves cognitive performance. These effects are possibly due to the recovery of a cortical balance, via Locus Coeruleus (LC) modulation, whose activity is powerfully affected by the sensorimotor trigeminal input. The role of this functional axis was further investigated in subjects without overt occlusal or dental problems. In these individuals, the EMG asymmetry was significantly correlated to anisocoria at rest, with the dental arches open or in contact. Also in normal subjects, both the EMG and the pupil asymmetry during clenching could be significantly reduced by an orthotic (bite) correction. Closing the arches without bite increased anisocoria and reduced performance in the Spinnler-Tognoni matrices test, as well as the mydriasis induced by a haptic task. When the bite was interposed, anisocoria was reduced, while both performance and task-related mydriasis were enhanced. Since pupil size is considered a proxy of the LC activity, these results suggest that asymmetric occlusion biases the LC discharge and the hemispheric excitability, possibly via a sensorimotor trigeminal imbalance. Removing the anisocoria through bite correction re-establishes a symmetric LC discharge, improving performance and enhancing task-related mydriasis. Therefore, occlusal balancing may represent a tool for improving subjective performance and may be exploited for training and rehabilitative purposes., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: The Cone Beam Computed Tomography (CBCT) is currently being used as the most common diagnostic method to evaluate the bone density of the maxilla and the mandible for planning dental implant. Aim: The aim of the study is to check the quantitative alveolar bone density in complete or partial edentulous and dentulous male and female patients among Riyadh sample population in Saudi Arabia., Materials and Methods: The study involved a cross-sectional analysis of 231 consecutive CBCT images of 231 different patients (115 males and 116 females). The scans were of Saudi National patients who were partially or completely edentulous without any bone infections in the maxilla and the mandible. The findings are presented as descriptive statistics and inferential statistics: student -t-test for two group means, ANOVA for three groups, Post-hoc LSD test for multiple comparisons, Levene statistics for testing the homogeneity of variances and a statistical significance at 5% level., Results: Comparison of mean alveolar bone density in maxillae of dentulous male smokers showed a statistically significant difference for bucco-cortical plate and cancellous bone among different regions. In dentulous male nonsmokers, no significant difference was observed for maxillary regions, while in mandibular areas, a statistically significant difference was seen for buccal cortex, palatal cortex, and cancellous bone among different regions. While studying the scans of female dentulous patients, a statistically significant difference was observed in alveolar bone density for all the areas., Conclusion: Evaluation of bone density is an important step in treatment planning and this study was aimed to provide insight into bone density patterns of population in Riyadh, Saudi Arabia. Further similar studies in different populations can help in planning for more efficient treatment outcomes., Competing Interests: None

Statement of Problem: The healing pattern after surgical resection of tumors of the oral cavity involving the maxilla may vary from one patient to another. The result may be open communication between the oral and nasal cavities (open defect) or complete oronasal separation after healing of the defect area (closed defect)., Purpose: The purpose of this clinical study was to compare masticatory function and oral health-related quality of life (OHRQoL) between patients with closed and open defects who had undergone a partial maxillectomy and were wearing dentomaxillary prostheses., Material and Methods: Thirty-eight participants who had undergone a partial maxillectomy and who were wearing dentomaxillary prostheses were enrolled between September 2014 and April 2016. Participants were assigned to 2 groups according to the type of defect after healing: 19 participants had a closed defect, and 19 participants had an open defect. Masticatory function was evaluated objectively and subjectively. The objective measurement was food-mixing ability, which was assessed using color-changeable chewing gum. The subjective measurement was perceived mastication ability, rated as a masticatory score based on the patient's responses to a 35-item food intake questionnaire. OHRQoL was assessed using the Geriatric Oral Health Assessment Index (GOHAI). The GOHAI questionnaire consists of 12 items reflecting 3 hypothesized domains of the impact of oral disease: physical function, psychosocial function, and pain or discomfort. Differences in the scores obtained by the 3 measurements were compared between the 2 groups, using the Wilcoxon rank-sum test (α=.05)., Results: No significant differences were seen between the 2 groups in objective mixing ability, subjective masticatory score, or GOHAI (P>.05). Regarding the GOHAI physical function domain, only the swallowing item was significantly lower (P=.025) in participants with an open defect than in participants with a closed defect. Regarding the GOHAI psychological function domain, the item related to patients' psychological worries or concerns about their teeth, gingival tissue, or dentures was significantly lower (P=.045) in patients with an open defect than in those with a closed defect. Other items related to physical function, psychological function, and pain or discomfort were not significantly different (P>.05) between the 2 groups., Conclusions: The closed or open defect in patients who had undergone a partial maxillectomy may not influence patients' masticatory function and overall OHRQoL if they have adequate prosthetic rehabilitation. However, special consideration should be given to patients with an open defect with regard to swallowing function and psychological concerns in order to improve their OHRQoL., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to compare the mandibular movements in older people with and without temporomandibular disorder (TMD) associated with rheumatoid arthritis (RA)., Study Design: Thirty partially or completely edentulous older adults (65.33 ± 4.7 years) were assigned to 2 groups: (1) with RA and TMD and (2) without RA and TMD. Chewing movements of the jaws during mastication of the test material (Optocal) and the range of mandibular movements were evaluated by using the JT-3-D kinesiographic device before and after new removable prosthesis insertion. Multiple comparisons were made with analysis of variance (ANOVA) and the Tukey-Kramer test., Results: Comparisons between the 2 groups before and after new prosthesis insertion revealed that the RA and TMD group had reduced opening angles (P < .05) during chewing. After insertion of new prostheses, both groups showed increased opening and closing angles during chewing (P < .05). The mandibular range of motion results showed that patients with RA and TMD exhibited lower aperture and laterality movements (P < .05) compared with controls before and after new prosthesis insertion. However, there was an increase in aperture, lefty laterality, and protrusion values after new prosthesis insertion in both groups., Conclusions: TMD associated with RA may impair mandibular movements. Well-fitted prostheses may improve mandibular movements in older adults, especially those with RA., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To investigate the influence of maturation timing upon histological, histomorphometric and clinical outcomes when deproteinized bovine bone mineral (DBBM) was used as a sole biomaterial for staged maxillary sinus floor augmentation (MSFA)., Materials and Methods: Patients with a posterior edentulous maxillary situation and a vertical bone height ≤ 4 mm were included in this study. A staged MSFA was carried out. After MSFA with DBBM as a sole grafting material, biopsy cores were harvested with simultaneous implant placement followed by a healing period of 5, 8, and 11 months, respectively. Micro-CT, histologic and histomorphometric analyses were performed., Results: Forty-one patients were enrolled and 38 bone core biopsies were harvested. Significantly greater BV/TV was observed between 5- and 8-month healing from micro-CT analysis. Histomorphometric analyses showed the ratio of mineralized newly formed bone increased slightly from 5 to 11 months; however, no statistically significant difference was reached (p = .409). Residual bone substitute decreased from 37.3 ± 5.04% to 20.6 ± 7.45%, achieving a statistical significant difference from of 5 up to 11 months (p < .01). Moreover, no implant failure, biological or technical complication occurred after 12-month follow-up of functional loading., Conclusion: DBBM utilized as sole grafting material in staged MSFA demonstrated to be clinically effective regardless of the healing period. Histomorphometrical and micro-CT assessments revealed that at later stages of healing (8 and 11 months) there is a higher proportion of newly-bone formation compared to earlier stages (5 months). Moreover, the longer the maturation period, the substantially lesser remaining biomaterial could be expected. Even though, these facts did not seem to negatively impact on the implant prognosis 1-year after loading., (© 2016 Wiley Periodicals, Inc.)

Aim: To examine whether posterior teeth occlusion is associated with functional dependence regardless of the number of natural teeth among Japanese nursing home residents., Methods: The present cross-sectional study included 234 residents aged >60 years from eight nursing homes in Aso City, Japan. Functional dependence in basic activities of daily living was measured using the Barthel Index, and the primary outcome was independence for essential personal care (Barthel Index ≥ 60 points). Posterior teeth occlusion was assessed by a dentist using the total number of functional tooth units, depending on the number and location of the remaining natural and artificial teeth on implant-supported, fixed, and removable prostheses. Logistic regression models were used to assess univariate and multivariate associations between the total number of functional tooth units and independence for essential personal care. Models were sequentially adjusted for the number of natural teeth, demographic characteristics, socioeconomic status, health behaviors and comorbidities., Results: Independence for essential personal care was found in 14.1% of participants. Greater total numbers of functional tooth units were significantly associated with greater odds of independence for essential personal care (odds ratio 1.12; 95% confidence interval 1.01-1.24). The association remained significant after adjustment for the number of natural teeth and other possible confounders (odds ratio 1.14, 95% confidence interval 1.01-1.29)., Conclusions: Posterior teeth occlusion was independently associated with functional dependence among nursing home older residents in Japan. The maintenance and restoration of posterior teeth occlusion might be preventive factors against late-life functional decline. Geriatr Gerontol Int 2017; 17: 622-627., (© 2016 Japan Geriatrics Society.)

Objective: The objective of this study was to compare the masticatory efficiency in subjects with shortened dental arch (SDA) before and after restoration with removable partial denture (RPD)., Materials and Methods: This was a prospective study carried out on 36 consecutive patients. The subjects were asked to chew 5 g of a measured portion of fresh raw carrot for 20 specified numbers of strokes. The raw carrot was recovered into a cup and strained through a standard mesh sieve of 5 mm by 1 mm, it was air dried for 30 min and weighed with FEM digital series weighing scale. The masticatory performance ratio was then determined., Result: The age range of the subjects was 34-64 years with the mean age being 52.2 ± 8.2 years. The difference between the total masticatory performance score at the post- and pre-treatment phases was statistically significant (P = 0.001). The improvement in masticatory performance was marked among the younger age groups (P = 0.001), unilateral free end saddle subjects (P = 0.001), and among the male gender (P < 0.05)., Conclusion: Masticatory performance improved with the provision of RPD. However, the improvement was marked among the younger age groups, unilateral free end saddle subjects, and the male gender; thereby supporting the need for RPDs in patients with SDA.

Objectives: This study investigated chewing function in elderly individuals with Alzheimer's disease (AD) and correlated chewing function with cognitive status., Materials and Methods: Sixteen elderly individuals with mild AD (mean age 76.7 ± 6.3 years; 8 men, 8 women) and 16 age and gender-matched healthy controls (mean age 75.23 ± 4.4 years; 8 men, 8 women) were included in this study. All volunteers wore removable prostheses: 11 were totally edentulous and five were partially edentulous in each group. Chewing function was evaluated via masticatory performance (MP) using Optocal chewable test material and a sieve fractionation method. Cognitive functioning was assessed by the Mini Mental State Exam (MMSE), administered by a trained examiner. Data were analyzed by non-paired t test and Pearson's correlation with α = 0.05., Results: Compared to controls, mild AD patients had decreased MP (P < 0.01) and MMSE (P = 0.01). MP showed a moderate negative correlation with MMSE (r = -0.69)., Conclusions: Mild AD was associated with impaired chewing function., Clinical Relevance: Knowledge that mild AD has an impact on chewing is important for dental professionals in decision-making related to prosthetics and general dental treatment.

Purpose: This study aimed to evaluate the radiographic bone level changes of implants positioned via the split-crest procedure both in the maxilla and mandible at a long-term follow-up., Materials and Methods: Seventy-one patients were retrospectively enrolled in the study. The placement of 137 dental implants was performed in the edentulous premolar or molar region after a split-crest ridge expansion procedure. Implants followed a delayed loading protocol. Intraoral digital radiographs were performed at baseline, upon implant placement, at 70 days (following placement of the provisional prosthesis), and on a yearly basis during followup. Crestal bone levels were evaluated at the baseline, upon provisional prosthesis placement, at 12, 36, and 60 months, and at the long-term follow-up of healing from implant placement., Results: The patients underwent a mean follow-up of 6.54 ± 1.32 years, from which the implant survival rate was reported at 98.54%. Within the first year from implant placement, a bone loss resulted at a mean value of -1.11 ± 0.44 mm. After almost 3 years from implant placement, a mean bone gain of +0.89 ± 0.39 mm was reported, which was statistically significant compared with 12-month values (P < .05). From this point, bone levels remained stable, reporting similar values over time, with no significant differences (P > .05)., Conclusion: A mean vertical bone gain of +0.89 ± 0.39 mm was observed after almost 36 months after implant positioning.

We aimed to investigate mastication predominance in healthy dentate individuals and patients with unilateral posterior missing teeth using objective and subjective methods. The sample comprised 50 healthy dentate individuals (healthy dentate group) and 30 patients with unilateral posterior missing teeth (partially edentulous group). Subjects were asked to freely chew three kinds of test foods (peanuts, beef jerky and chewing gum). Electromyographic activity of the bilateral masseter muscles was recorded. The chewing side (right side or left side) was judged by the level of root mean square electromyographic amplitude. Mastication predominance was then objectively assessed using the mastication predominant score and the mastication predominant index. Self-awareness of mastication predominance was evaluated using a modified visual analogue scale. Mastication predominance scores of the healthy dentate and partially edentulous groups for each test food were analysed. There was a significant difference in the distribution of the mastication predominant index between the two groups (P < 0·05). The mastication predominant score was weakly correlated with self-awareness of mastication predominance in the healthy dentate group, whereas strong correlation was observed in the partially edentulous group (P < 0·05). The results suggest that the individuals with missing unilateral posterior teeth exhibited greater mastication predominance and were more aware of mastication predominance than healthy dentate individuals. Our findings suggest that an objective evaluation of mastication predominance is more precise than a subjective method., (© 2016 John Wiley & Sons Ltd.)

The aim of this multicentre study was to investigate the effect of prosthetic restoration for missing posterior teeth on mastication in patients with shortened dental arches (SDAs). Partially dentate patients who had an intact teeth in anterior region and missed distal molar(s) (2-12 missing occlusal units) classified as Kennedy Class I or Class II were recruited from seven university-based dental hospitals in Japan. Of the 125 subjects who underwent baseline (pre-treatment) and follow-up/post-treatment evaluation, 53 chose no replacement of missing teeth and 72 chose treatment with removable partial dentures (n = 53) or implant-supported fixed partial dentures (n = 19). Objective masticatory performance (MP) was evaluated using a gummy jelly test. Perception of chewing ability (CA) was rated using a food intake questionnaire. In the no-treatment group, mean MP and CA scores at baseline were similar to those at follow-up evaluation (P > 0·05). In the treatment group, mean MP after treatment was significantly greater than the pre-treatment mean MP (P < 0·05). However, the mean perceived CA in the treatment groups was similar at pre- and post-treatment (P > 0·05). In a subgroup analysis of subjects in the treatment group, subjects with lower pre-treatment CA showed a significant CA increase after treatment (P = 0·004), but those with higher pre-treatment CA showed a significant decrease in CA (P = 0·001). These results suggest that prosthetic restoration for SDAs may benefit objective masticatory performance in patients needing replacement of missing posterior teeth, but the benefit in subjective chewing ability seems to be limited in subjects with perceived impairment in chewing ability before treatment., (© 2016 John Wiley & Sons Ltd.)

The relationship between type 2 diabetes oral physiology, nutritional intake and quality of life has not been fully elucidated. We assessed the impact of type 2 diabetes - exclusive or associated with hypertension with beta-blockers treatment - on oral physiology, mastication, nutrition and quality of life. This cross-sectional study was performed with 78 complete dentate subjects (15 natural teeth and six masticatory units minimum; without removable or fixed prostheses), divided into three groups: diabetics (DM) (n = 20; 45·4 ± 9·5 years), diabetics with hypertension and receiving beta-blockers treatment (DMH) (n = 19; 41·1 ± 5·1 years) and controls (n = 39; 44·5 ± 11·7 years) matched for gender, age and socioeconomic status. Blood glucose, masticatory performance, swallowing threshold, taste, food intake, stimulated and unstimulated salivary flow, pH and buffering capacity of saliva were assessed. Glycemia was higher in DM than in controls (P < 0·01). No differences were observed between DM and controls for nutrition and quality of life. Both stimulated and unstimulated salivary flow rate were lower in DMH (P < 0·01), which also presented the lowest number of teeth and masticatory units (P < 0·0001), and reduction in the number of chewing cycles (P < 0·01). Controls showed lower Decayed Missing Filled Teeth index (DMFT) scores in comparison with DMH (P = 0·021). Masticatory performance and saliva buffering capacity were similar among groups. Exclusive type 2 diabetes did not alter oral physiology, nutrition or quality of life. However, when hypertension and beta-blockers treatment were associated with diabetes, the salivary flow rate, chewing cycles and number of teeth decreased., (© 2016 John Wiley & Sons Ltd.)

Previous studies have identified various factors related to masticatory performance. This study was aimed to investigate variations and impacts of factors related to masticatory performance among different occlusal support areas in general urban population in Japan. A total of 1875 Japanese subjects (mean age: 66·7 years) were included in the Suita study. Periodontal status was evaluated using the Community Periodontal Index (CPI). The number of functional teeth and occlusal support areas (OSA) were recorded, and the latter divided into three categories of perfect, decreased and lost OSA based on the Eichner Index. Masticatory performance was determined by means of test gummy jelly. For denture wearers, masticatory performance was measured with the dentures in place. The multiple linear regression analysis showed that, when controlling for other variables, masticatory performance was significantly associated with sex, number of functional teeth, maximum bite force and periodontal status in perfect OSA. Masticatory performance was significantly associated with number of functional teeth, maximum bite force and periodontal status in decreased OSA. In lost OSA, masticatory performance was significantly associated with maximum bite force. Maximum bite force was a factor significantly influencing masticatory performance that was common to all OSA groups. After controlling for possible confounding factors, the number of functional teeth and periodontal status were common factors in the perfect and decreased OSA groups, and only sex was significant in the perfect OSA group. These findings may help in providing dietary guidance to elderly people with tooth loss or periodontal disease., (© 2015 John Wiley & Sons Ltd.)

Implant prosthesis of dentition defect is characteristic of remaining teeth and implants exist at the same time, so the remaining teeth occlusal conditions related to the final occlusal design is to maintain, adjust or re-establish the original dentition occlusion. Therefore, full evaluation of remaining teeth occlusion before restoration, clear prognosis, balancing the occlusal force distribution of natural teeth and implants, and carrying out the predictable occlusal design in the entire process of implant prosthesis can minimize the adverse events after implant prosthesis. Based on the typical cases in this paper, three occlusal design types of occlusal maintain-implant restoration, occlusal adjustment-implant restoration and occlusal reconstruction-implant restoration will be expounded respectively.

Objective: To investigate the relationship of dental status to food diversity among older Japanese., Design and Setting: A community-based cross-sectional study conducted in the town of Tosa, Kochi Prefecture, Japan., Methods: The study participants were 252 Japanese (84 men and 168 women, average age 81.2 years) and dentate participants were classified into three groups: 1-9 teeth, 10-19 teeth and 20 or more teeth. Food diversity was assessed as a validated measure of dietary quality using the 11-item Food Diversity Score Kyoto (FDSK-11), which evaluates frequency of consumption of 11 main food groups. Multivariable analysis of the differences in FDSK-11 score ranging from 0 to 11, with a higher score indicating greater food diversity, among the three dental status groups was conducted using general linear models. All the performed analyses were stratified by gender., Results: There was no association between dental status and food diversity score in models for men. In contrast, women with ≤ 9 teeth and with 10-19 teeth had significantly lower FDSK-11 scores than women with ≥ 20 teeth after adjusting for confounders (p < 0.001 and p = 0.009, respectively). Additionally, there was a trend toward lower scores for FDSK-11 with fewer teeth (p = 0.001)., Conclusion: A less varied diet, as indicated by low FDSK-11 score, was observed in female participants with fewer teeth. Tooth loss was associated with poor diet quality among older Japanese women.

Introduction: Phonetic adaptation is a complex biological phenomenon with a highly individual course, depending on the patient's motivation to use prosthesis, on the functional quality of removable dentures. The aim of the study was to estimate phonetic adaptation in patients with partial dentures, connecting it to alteration in speech quality and dentures functional value., Materials and Methods: We examined some peculiarities of phonetic adaptation in 50 patients with removable dentures (50 patients with natural dentition were invited for the control group). The standardized evaluation protocols (12 speech quality determining parameters) were developed separately for Latvian and Russian native speakers. 500 speech video samples were recorded and analysed according to pre-established guidelines. The connection of speech quality and the functional quality of the dentures was assessed. Statistical analysis was performed using SPSS 20.0. P values equal to or less than 0.05 were considered to be statistically significant., Results: In patients with appropriate functional quality of removable dentures distorted speech production was detected in 25% (pk=0.008) cases and in patients with inappropriate functional quality of the prosthesis - in 40% (pk<0.001). Patients with appropriate dentures functional value were satisfied with their speech performance in 96% (pk=0.674), in the group with inappropriate dentures functional value only 59% (p<0.001) rated their speech quality positively., Conclusion: Phonetic adaptation to removable dentures depends on the patient's individual adaptation capacity, prosthetic design and functional value. Thus statistically significant correlation between removable partial dentures functional value, duration of usage and the degree of patients' phonetic adaptation (p<0.001) may be considered to be confirmed.

Statement of Problem: When implants are incorporated into an existing partial removable dental prosthesis, the acrylic resin base can fracture. It is therefore essential to study the mechanical behavior of partial removable dental prostheses by using stress and deformation analysis., Purpose: The purpose of this study was to analyze the effect of the occlusal rest position on the implant-assisted partial removable dental prosthesis by finite element analysis., Material and Methods: A Faro Arm scan was used to extract the geometrical data of a human partially edentulous mandible. A standard plus regular neck (4.8×12 mm) implant and titanium matrix, tooth roots, and periodontal ligaments were modeled by using a combination of reverse engineering in Rapidform XOR2 and solid modeling with the Solid Works CAD program. The model incorporated a partial removable dental prosthesis and was loaded with standard bilateral forces. A uniform pressure was applied on the occlusal surface so as to generate an equivalent net force of 120 N for both the left and right prosthesis. The finite element analysis program ANSYS Workbench was used to analyze the stress and strain distributions in the implant-assisted partial removable dental prosthesis., Results: Maximum stresses were significantly high for the metal framework compared to the acrylic resin surface, and these stresses were different for the mesial and distal arm designs. The maximum stress in the metal framework for the mesial arm design was 614.9 MPa, and it was 796.4 MPa for the distal arm design. The corresponding stresses in the acrylic resin surface were 10.6 and 8.6 MPa., Conclusions: Within the limitation of this study, it was found that moving the position of the occlusal rest from the mesial to distal side of the abutment teeth improved the stress distribution in the metal framework and acrylic resin denture base structures., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

This preliminary study evaluated the adjunctive supporting role of diverse implant positions on stress distribution in a Class I removable partial denture (RPD) design. Nine three-dimensional finite element models were prepared to simulate mandibular RPD designs with three different loading conditions applied. Implant supported designs demonstrated lower stress value concentrations and mucosal displacement.

Bite force is a significant component of chewing and masticatory function. The literature lacks studies that compare bite force values of implant-supported fixed bridges to natural dentition within same subjects. The objective of the study was to assess maximum occlusal bite force (MBF) among patients with an implant-supported fixed prosthesis and compare it to their opposite dentate side and also to determine the effect of gender, age and Body Mass Index (BMI) on maximum occlusal bite force. Forty patients (20 males and 20 females, mean age = 42.7 ± 9.6 years) with an implant-supported fixed prosthetic rehabilitation on one side and dentate on the other side were recruited into this study. Participants' MBF were measured bilaterally at the first molar region using a digital hydraulic occlusal force gauge (GM10). The measurements were repeated three times (with 45 s intervals between times) for each side, and the highest value of the bite force (MBF) was recorded for each side. The mean MBF was 577.9 N at the implant-supported prosthesis side and 595.1 N at the dentate side. The average MBF was higher at the dentulous side (P < 0.05). Maximum occlusal bite force was higher in males and participants with higher weight and height. However, BMI was not significantly related to MBF values. Maximum occlusal bite force values at the dentate side were slightly (3%) but significantly higher than MBF at implant-supported prosthesis side. Males, taller patients and patients with higher weights had higher MBF values. Body mass index was not significantly related to MBF values., (© 2014 John Wiley & Sons Ltd.)

Objectives: This study measured swallowing threshold parameters and nutrient intake in partially dentate subjects rehabilitated by conventional free-end removable partial dentures (RPD) and by RPD over posterior implant retainers and ball attachments (BA)., Materials and Methods: Eight subjects (two men and six women; mean age 60.1 ± 6.6 years old) received conventional total maxillary dentures and free-end RPD in the mandible. Two months after denture insertion, swallowing threshold and nutrient intake assessments occurred, which included an evaluation of the number of masticatory cycles and medium particle size (X₅₀) of a silicone test material (Optocal). A 3-day food diary verified nutrient intake based on a standard Brazilian Food Composition Table. Then, osseointegrated implants were placed bilaterally in the mandibular first molar region, followed by BA, which was fitted in the RPD bases after healing. After 2 months of the RPD over implants and BA use, variables were again assessed. Wilcoxon signed rank tests evaluated the data (P < 0.05)., Results: Masticatory cycles did not differ (P > 0.05); however, subjects showed decreased X₅₀ values at the swallowing moment (P = 0.008) and increased daily energy (P = 0.008), carbohydrate (P = 0.016), protein (P = 0.023), calcium (P = 0.008), fiber (P = 0.016), and iron (P = 0.016) intake with RPD implants and BA inserts. No differences were found in fat consumption (P > 0.05)., Conclusion: Implants and BA retainers over a free-end RPD resulted in smaller swallowed median particle size and improved nutrient intake., (© 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.)

It is well known that shortened dental arch decreases masticatory function. However, its potential to change brain activity during mastication is unknown. The present study investigates the effect of a shortened posterior dental arch with mandibular removable partial dentures (RPDs) on brain activity during gum chewing. Eleven subjects with missing mandibular molars (mean age, 66.1 years) on both sides received experimental RPDs with interchangeable artificial molars in a crossover trial design. Brain activity during gum chewing with RPDs containing (full dental arch) and lacking artificial molars (shortened dental arch) was measured using functional magnetic resonance imaging. Additionally, masticatory function was evaluated for each dental arch type. Food comminuting and mixing ability and the perceived chewing ability were significantly lower in subjects with a shortened dental arch than those with a full dental arch (P < 0.05). Brain activation during gum chewing with the full dental arch occurred in the middle frontal gyrus, primary sensorimotor cortex extending to the pre-central gyrus, supplementary motor area, putamen, insula and cerebellum. However, middle frontal gyrus activation was not observed during gum chewing with the shortened dental arch. These results suggest that shortened dental arch affects human brain activity in the middle frontal gyrus during gum chewing, and the decreased middle frontal gyrus activation may be associated with decreased masticatory function., (© 2014 John Wiley & Sons Ltd.)

Statement of Problem: The human mandible flexes during different jaw movements. Mandibular flexure is known to be restricted when natural dentition is restored with long-span fixed prostheses, but its effect on implant-supported fixed prostheses is unknown. Restriction of mandibular movement by implant-supported fixed prostheses may lead to excess strain accumulation, which could affect the outcome of implant treatment., Purpose: The purpose of this study was to investigate the influence of mandibular flexure on the implant bone interface by measuring the strain distribution in the body of the mandible at the periimplant level and at the implant framework level during the unilateral loading of a long-span implant-supported fixed prosthesis., Material and Methods: A partially edentulous mandible model with the mandibular left premolars and molars missing was fabricated in epoxy resin. Two implants were placed in the edentulous area, one in the position of the first premolar and one in the position of the second molar. Strain gauges were cemented at the implant bone interface parallel to each implant on the body of the mandible and on the framework. Three screw-retained, 3 × 3-mm bar-shaped frameworks were cast from cobalt-chromium alloy. The fit of these frameworks was deemed clinically acceptable with a routine clinical assessment technique. The mandible model was suspended by elastic cords to a universal testing machine. A 50-N load cell was placed on the occlusal surface of the right first molar. The mandible model was then loaded to 50 N on the working side first without any framework and then a second time with the framework in place. Information from the strain gauges were collected with a computer for analysis., Results: When the mandible model was loaded without the implant framework, the buccal aspect of the body of the mandible experienced mainly compression, whereas the lingual aspect was mainly in tension on the working side under unilateral loading. At the implant-bone interface, compression strain was detected on the mesial aspect of the mesial implant. When frameworks were placed and a unilateral load applied, compression was detected on the mesial and buccal aspect of the mesial implant with all 3 frameworks. The amount of strain recorded was higher than that recorded without any framework in place., Conclusions: Mandibular flexure occurred during unilateral loading. The amount of strain transmitted to the implants increased with the screw-retained fixed-implant frameworks in place. The amount of strain introduced by mandibular flexure under unilateral loading may not be enough to stimulate bone remodeling; however, the accumulative strain generated by mandibular flexure under cyclic loading and its relationship with bone remodeling is unclear., (Copyright © 2014 The Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The main goal of prosthetic treatment is to restore masticatory function. However, insufficient evidence supports the recommendation of one specific prosthetic intervention for partially edentulous patients. Function after the use of three different prostheses by the same partially edentulous subject. Mastication was assessed in 12 subjects (mean age 62.6 ± 7.8 years) after they had used removable partial dentures (RPDs), implant-supported partial dentures (IRPDs) and implant-fixed partial dentures (IFPDs). Masticatory ability (MA) was estimated by visual analogue scale questionnaire, while the mandibular chewing motion was evaluated by kinesiographic device, representing an objective measurement of masticatory function. Data were analysed by repeated-measures anova followed by Tukey-Kramer (P < 0.05). MA improved after IRPD and IFPD use (P < 0.05). Opening, closing and total cycle time duration were reduced after both IRPD and IFPD use (P < 0.05), irrespectively the implant prosthesis type. IFPDs and IRPDs restore the masticatory function of partially edentulous patients better than RPDs., (© 2014 John Wiley & Sons Ltd.)

Statement of Problem: Some patients may opt for a prosthetic rehabilitation without replacing all missing teeth, finishing treatment with a reduced dental arch. This choice may be due to biologic reasons or financial restrictions. It is unclear if a reduced dental arch functions as well as a complete dental arch., Purpose: The purpose of this study was to analyze whether shortened dental arches could result in tooth displacement., Material and Methods: Four different 3-dimensional maxillary and mandibular arches with different levels of arch length reduction were created. In all models, anatomic structures that represent the temporomandibular joint, cortical and cancellous bone, enamel, dentin, and periodontal ligament were modeled. Mechanical properties were attributed to each anatomic component, and a total occlusal load of 100 N on masseter, temporal, and medial pterygoid muscles was simulated for each model. The MSC. Patran software was used for the preprocessing and postprocessing of the biomechanical analysis of the models. One complete dental arch was used as the control., Results: The simulations showed that shortened dental arches presented greater tooth displacements than those found in a complete dental arch. The changes in mandibular tooth position were greater than those observed in the maxillary arches. In finite element models 1 and 2, the largest maxillary displacements were found for posterior teeth., Conclusions: Decreasing numbers of occlusal units resulted in increasing amounts of displacements of the remaining teeth, which may compromise dental stability in patients with shortened dental arches., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Aim: In this study, we investigated the effect of differences in periodontal status in the masticatory performance of dentate subjects with the same occlusal supporting area., Materials and Methods: The subjects of the analysis were classified into those of Eichner A1-3 (n = 1094) and Eichner B1-4 (n = 529). Subjects' periodontal status was evaluated on the basis of the Community Periodontal Index (CPI). The number of functional teeth and occlusal support were investigated, the latter on the basis of the Eichner Index. Furthermore, masticatory performance was investigated by means of test gummy jelly. For each group, periodontal status was classified in two different ways, either with/without moderate periodontitis (CPI Code ≤2/≥3) or with/without severe periodontitis (CPI Code ≤3/4), and masticatory performance was compared between the various groups., Results: In subjects who were Eichner A1 and B3, masticatory performance was significantly lower in subjects with moderate periodontitis compared with those without, and in subjects with severe periodontitis compared with those without., Conclusion: Periodontal disease affects masticatory performance not only if occlusion is established by natural dentition with no tooth loss but also if occlusal support has decreased., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: The aim of this study was to evaluate the radiographic bone level changes after delayed implant placement at medium-term follow-up, with three elements kept constant: keratinized gingiva thickness, implant axes perpendicular to the opposing occlusal surface, and implants with a collar of 2 mm., Materials and Methods: Patients treated in a private practice setting were retrospectively enrolled in the study. They underwent delayed placement (4 to 8 weeks after extraction) of dental implants in edentulous premolar or molar regions. Implants followed a delayed loading protocol. Crestal bone levels were measured at baseline; at provisional prosthesis placement; at 1, 3, and 5 years; and at medium-term follow-up of healing from implant placement., Results: One hundred twenty patients received 135 implants (one or two implants per patient); 3 implants were lost. After a mean follow-up period of 9.71 ± 4.88 years, a survival rate of 97.76% was reported. At 1 year after implant placement, mean bone loss of -1.5 ± 0.62 mm was found. At almost 3 years post-implant placement, a mean bone gain of +1.20 ± 0.49 mm was seen, which was statistically significantly different compared with 1 year. After this point, the bone levels remained stable; similar values were reported over time, with no significant differences., Conclusions: The mean vertical bone gain of +1.20 ± 0.49 mm seen at almost 3 years after implant placement in this study may be supported by both clinical parameters as presence of sufficiently thick keratinized gingiva (3 mm), implants with a 2-mm collar, and the axis of implant insertion perpendicular to the opposing occlusal surface.

To assess associations between occlusal tooth wear and shortened dental arches (SDA) in Chinese 40 years and older subjects. From a sample of 1462 urban and rural adults, those presenting with SDA (n = 150) were compared with a control group of 65 randomly selected subjects with complete dentitions (CDA). Occlusal wear was assessed using a modified Smith and Knight index - the occlusal tooth wear index (OWTI) - and analysed using multivariate (logistic) regression. There was no significant effect from SDA on severe occlusal wear (OTWI score 3 or 4: OR = 2.016; 95% CI = 0.960-4.231; P = 0.064). Higher age was associated with severe occlusal wear (P values ≤0.007) and with higher mean OTWI scores; urban had less often severe occlusal wear than rural residents (OR = 0.519; P = 0.008). Higher mean OTWI scores were associated with rural residents, except for anterior teeth. Females had lower mean OTWI score for anterior teeth (effect = -0.153; P = 0.030). Premolars in SDA had higher mean OTWI scores compared with those in CDA (effect = +0.213; P = 0.006). In SDA, more posterior occluding pairs (POPs) were associated with lower mean OTWI sores for anterior teeth (effect: -0.158; P = 0.008) and higher scores for molars (effect: +0.249, P = 0.003). Subjects with SDA or CDA presented comparable occlusal wear, but premolars in SDA tend to have higher probability for having occlusal wear. Fewer numbers of POPs were associated with more wear in anterior teeth., (© 2013 John Wiley & Sons Ltd.)

Recording the track of the mandibular hinge axis and consequently ascertaining the posterior determinants is one of the key requirements for accurately simulating individual oral conditions in the (virtual) articulator. The aim of this study was to determine the reliability of computerized condylar path inclination angle (CPIA) measures and to assess whether the reliability depends on the mandibular dentition. Sagittal and transverse CPIA were measured using computerized axiography (Cadiax Compact 2) at two separate sessions in prosthodontic patients (mean age +/- SD: 64.3 +/- 10.3 years; female: 45%) who were classified into three dentition categories (fully dentate: N = 19, partially dentate: N = 27 and edentulous: N = 19). These measurements were repeated three times at both sessions without removing the computerized axiograph. Reliability was assessed in multilevel analyses using the subject as a grouping variable in linear random-intercept models. Considering all assessment procedures, the patient-specific differences explained 75% of the variance for the sagittal and 38% for the transverse condylar path. This corresponds to the overall reliability of both the sagittal and the transverse CPIA assessment. The dentition had no significant impact on the reliability of the measurements. The sagittal CPIA can be assessed with satisfactory reliability using computerized axiography. It is independent of the status of the dentition, which has no statistically significant impact on the measures. Transverse CPIA measurements have shown poor reliability. Therefore, the electronic determination of the sagittal CPIA is a reliable procedure that can be applied in patients irrespective of the status of the mandibular dentition.

Unlabelled: Removable partial denture prostheses are still being used for anatomic, medical and economic reasons. However, the impact on chewing parameters is poorly described., Objectives: The objective of this study was to estimate the impact of removable partial denture prosthesis on masticatory parameters., Material and Methods: Nineteen removable partial denture prosthesis (RPDP) wearers participated in the study. Among them, 10 subjects were Kennedy Class III partially edentulous and 9 with posterior edentulism (Class I). All presented a complete and full dentate opposing arch. The subjects chewed samples of carrots and peanuts with and without their prosthesis. The granulometry of the expectorated boluses from carrot and peanuts was characterized by median particle size (D50), determined at the natural point of swallowing. Number of chewing cycles (CC), chewing time (CT) and chewing frequency (CF=CC/CT) were video recorded., Results: With RPDP, the mean D50 values for carrot and peanuts were lower [Repeated Model Procedures (RMP), F=15, p<0.001] regardless of the type of Kennedy Class. For each food, mean CC, CT and CF values recorded decreased (RMP, F=18, F=9, and F=20 respectively, p<0.01). With or without RPD, the boluses' granulometry values were above the masticatory normative index (MNI) determined as 4,000 µm., Conclusion: RPDP rehabilitation improves the ability to reduce the bolus particle size, but does not reestablish fully the masticatory function., Clinical Relevance: This study encourages the clinical improvement of oral rehabilitation procedure.

Purpose: To assess the influence of different crown-implant (C/I) ratios and implant dimensions on periimplant stress in the partially edentulous posterior mandible by 3-dimensional finite element analysis (FEA)., Materials and Methods: Two implants were placed in the second premolar and first molar regions of the mandibular model. The implants were then splinted with a 2-unit fixed bridge. The influence of 3 parameters (C/I ratio, implant length, and implant diameter) on periimplant bone stress was then analyzed by using FEA., Results: C/I ratios showed a direct relationship with periimplant bone stress, but the absolute height of the clinical crown had a much more significant influence. The implant length had less influence on the periimplant bone stress than the implant diameter. Lower stress values were detected in wide-diameter implants, even in scenarios involving long crowns., Conclusions: Crown height is a more important factor affecting the periimplant bone stress than the C/I ratio for splinted implant-supported crowns. Two-unit fixed restorations with high C/I ratios may be successfully used with wide-diameter implants in the posterior mandible.

Purpose: The aim of this cross-sectional study was to investigate the relationship between body fat and masticatory function., Materials and Methods: One hundred dentate and partially edentulous participants (33 male; mean age, 39.7 ± 16.6 years) were selected. Body fat was established through body mass index (BMI). Masticatory function was evaluated by quantifying occlusal pairs and determining masticatory efficiency and swallowing threshold with the sieving method. During the swallowing threshold test, chewing rate was registered. Masticatory ability was also evaluated with a 5-point Likert scale questionnaire. Data were analyzed with Spearman and chi-square tests, as well as binary logistic regression analysis for the presence of increased BMI (α= 0.05)., Results: Age (rho = 0.517), occlusal pairs (chi-square = 26.353), masticatory efficiency (chi-square = 30.935), masticatory ability (chi-square = 25.132; p < 0.001), and swallowing threshold (chi-square = 8.730; p < 0.005) were related to BMI. Age (odds ratio, OR = 1.048, 95% CI = 1.008 to 1.089) and lower masticatory efficiency (OR = 4.792, 95% CI = 1.419 to 16.183) were predictive of increased body fat (p < 0.05). Gender (chi-square = 0.402, p= 0.526) and chewing rate (rho =-0.158, p= 0.117) were not related to BMI., Conclusions: These results suggest that people with lower masticatory efficiency may be at risk for increased body fat., (© 2012 by the American College of Prosthodontists.)

The aim of this study was to axiographically analyse the mobility of the condyles of the temporomandibular joints in patients with partial edentulism in lateral sections and try to specify whether the partial edentulism has an impact on the severity of temporomandibular disorders. 60 subjects with partial edentulism (different range groups) and 20 subjects in the control group (full dental arches) were examined. Every patient underwent a thorough clinical examination, including axiography conducted by means of Cadiax Compact II® system. The results show some correlation between the advancement of temporomandibular joint disorder, the range of partial edentulism and the abrasion of the residual teeth. In the study, a significant intensification of dysfunction symptoms and restricted condylar path was observed in patients with the largest partial edentulism and significant level of tooth wear of the residual teeth. A significantly higher percentage of asymptomatic subjects or those with minor dysfunction was also found among the patients with lowest-range partial edentulism in lateral sections.

The functional colopathies are frequent in digestive pathology and are particularly badly felt by African patients. The authors, after the determination of the masticatory efficiency score (classification of Verkindere) of 100 subjects affected by colopathies and diagnosed in the service of gastroenterology of Cocody University Hospital (Abidjan), attempt to determine the importance of the masticatory deficiency in functional colopathies. Among the toothless subjects with functional colopathies, the restoration of the masticatory efficiency by functional prosthetic rehabilitation constitutes an essential therapeutic act in the reduction of the symptoms of the functional colopathies and the improvement of the comfort of the patients. Patients' global care raises the interest of collaboration between odontologists and gastroenterologists for an efficient treatment.

Purpose: The aim of this study was to determine the influence of occlusal support length (OSL) of free-end removable partial dentures (RPDs) on masticatory function., Materials and Methods: Twenty-three subjects (mean age: 55.2 ± 8.4 years) who were edentulous in the maxilla and classified as Kennedy Class I in the mandible were selected. Subjects received new maxillary complete dentures and mandibular RPDs. Five OSL conditions were determined by RPD artificial tooth wear: full occlusal support (L1, control), OSL to first molar (L2), OSL to second premolar (L3), OSL to first premolar (L4), and absence of occlusal support (L5). Masticatory performance and efficiency were evaluated using the sieve method. Chewing rate was defined as the number of masticatory cycles per minute. Bolus selection opportunities and bolus breakage function were evaluated using the one-chew method. Qualitative and quantitative measurements of masticatory cycle patterns were recorded kinesiographically. Data were analyzed using repeated-measures analysis of variance and Friedman and Fisher exact tests (α = .05)., Results: Masticatory performance and efficiency decreased (P < .05) from L1 (5.46 ± 0.64 mm and 51.21% ± 19.44%, respectively) to L5 (6.24 ± 0.44 mm and 24.50% ± 15.98%, respectively). Chewing rate was higher for L4 than L1 (P < .05). Bolus selection chances and bolus breakage function decreased as OSL was reduced (P < .05); however, there were no differences in masticatory cycle pattern among the OSL conditions (P > .05)., Conclusion: Reduction of OSL altered masticatory function, thereby decreasing masticatory performance and efficiency resulting from a lower capacity to select and break down food.

Objectives: The aim of this study was to evaluate a screening test based on a food intake questionnaire to discriminate the masticatory ability of Taiwanese older adults with 20 and more natural teeth and at least 8 functional tooth units (FTUs) from the masticatory ability of those with fewer than 20 natural teeth and 8 FTUs., Materials and Methods: The subjects were 2244 patients (mean age, 60.4±10.0 years) recruited from 23 counties and cities in Taiwan. Information about their demographic data, dentition, and masticatory ability was collected. Masticatory ability was measured for 23 food groups comprising 35 common Taiwanese foods, and receiver operation characteristic curve analysis was performed., Results: The results showed that the final questionnaire included 14 food groups and a subject choosing 'difficult to eat' responses for 4 and more of these food groups had the same masticatory ability as individuals with fewer than 20 natural teeth and 8 FTUs., Conclusion: In conclusion, foods that are the most difficult to eat are not necessarily good discriminatory indicators. Hence, the 14-food group questionnaire can be considered the best screening test for masticatory ability of Taiwanese older adults in terms of the presence of 20 and more natural teeth and at least 8 FTUs., (© 2012 The Gerodontology Society and John Wiley & Sons A/S.)

Background: There are still no data available on the relationship between postural stability and occlusal status among the elderly., Objectives: To examine relationships between postural stability and occlusal status through a cohort study among elderly Japanese., Method: Oral examination, occlusal status, postural stability and a questionnaire were conducted and given to 87 community-dwelling Japanese at enrolment., Results: The average occlusal pressure of the female group was statistically higher than the male group while average occlusal pressure and postural stability length were lesser in the group with more remaining teeth. Postural stability area and number of remaining teeth showed statistically significant correlations. Postural stability length was lesser in the group with strong occlusal force. Furthermore, the number of decayed teeth was fewer in the good hygiene group., Conclusions: This study identified a close relationship between occlusal status and postural stability of Japanese older individuals. Occlusal hypofunction was observed more in those with occlusal problems, and a decrease in their occlusal functions resulted in postural instability., (© 2011 The Gerodontology Society and John Wiley & Sons A/S.)

Background and Objective: To quantitatively estimate tongue function, we developed a handy device for intraoral pressure measurement. The objective of this study was to assess maximum voluntary tongue pressure (MVTP) in Japanese frail elderly persons receiving nursing care services., Materials and Methods: The study included 42 men and 87 women, aged 58-100 years. To record MVTP, the participants were asked to compress the balloon (diameter: 18 mm) of the disposable intraoral pressure probe onto their palates for 7 s using the maximum voluntary effort of the tongue. Pressures were recorded three times at 1 min intervals., Results: Maximum voluntary tongue pressure was successfully measured in 111 persons. Mean (standard deviation) MVTP was 18 (12) kPa, with a range of 0-63 kPa. The remaining 18 persons could not accurately follow our instructions and MVTP could not be measured., Conclusion: In comparison with the reported standard value using the same device, the frail elderly persons included in our study were found to exert less MVTP than healthy dentate individuals. These results suggest the need for proper quantitative evaluation of oral function, including tongue capacity, at nursing care facilities., (© 2012 The Gerodontology Society and John Wiley & Sons A/S.)

Background: The purpose of this study was to locate the main occluding area when the reduced posterior occlusal support was treated with an implant-supported prosthesis and to evaluate the subsequent improvement in the masticatory ability as compared with removable partial dentures., Methods: Twenty-six patients with implant prostheses and 24 patients with removable partial dentures were recruited for this study. All patients had partially lost their posterior occlusal support. The first molar region in any quadrant was always included in the prosthetic region. Each subject was instructed to clench a piece of temporary stopping as a test food on the occluding area that was preferably used during mastication. The main occluding area was judged by locating the tooth on which the temporary stopping rested during clenching. Subjective masticatory ability was self-assessed by means of a questionnaire., Results: The main occluding area of the subjects in the implant group was located more posterior compared with the removable partial denture group. The level of masticatory ability in the implant group was the same as that in the control group., Conclusions: The location of the main occluding area and the masticatory ability of the subjects with implants were equivalent to those with healthy natural dentition., (© 2012 Australian Dental Association.)

Objective: The aim of this study was to assess the association between oral health-related quality of life (OHRQoL) measured by the oral impacts on daily performances (OIDP) inventory and chewing ability., Methods: The cluster sampling method was used to select a sample of 634 socially active independent community-dwelling elders. An oral examination was conducted and a questionnaire was implemented. After bivariate comparisons, a multivariable two-level logistic model was developed for the dichotomous OIDP indicator using the generalised linear mixed model., Results: The mean age of the participants was 74 years and 56.6% were women. Eight percent were edentulous, and the mean number of teeth was 17.7. Overall, 39.3% of participants had one or more oral impacts on daily performance. Elders with chewing ability of 0-49, 50-74 and 75-99% were approximately 120, 20 and seven times more likely to have oral impacts compared with those with full chewing ability, respectively. Elders reporting their oral health as 'fair' or 'better' were 68% less likely to have oral impacts than those with poor or very poor self-reported oral health., Conclusion: Among independent elders, amelioration of chewing ability including delivery of appropriate prosthodontic care might independently contribute to improving OHRQoL of elders by improving their physical, psychological and social wellbeing., (© 2012 The Gerodontology Society and John Wiley & Sons A/S.)

Background: Understanding of the biomechanical consequences of the stresses generated to the supporting bone during occlusal loading is significant for improving the design and clinical planning process in partial edentulism therapy., Objective:   The aim of this study was to analyse the distribution of strain and displacement on the partially dentate lower jaw rehabilitated with an partial denture (RPD) and to compare it to the strain and displacement distribution on a partially dentate lower jaw rehabilitated with a cantilever fixed partial denture (FPD)., Material and Methods: The experimental models were a partially dentate mandible with full-arch PFM crowns and RPD and a partially dentate mandible rehabilitated with a full-arch cantilever FPD. Strains and displacement were measured using the Digital Image Correlation Method., Results: Displacement values of the first experimental model ranged from 0.31 to 0.54 mm with strains from 1.35 to 2.34%. Analysis of the second experimental model results showed displacement values from 0 to 0.34 mm, while strains were in the range of 0-1.40%., Conclusion: Higher displacements and strains of bone tissue were observed below the RPD, especially in the region of the distal abutment and distal portion of the free-end saddle. Strains within bone and the bone-denture contact area were mostly influenced by the teeth and denture vertical displacement., (© 2011 The Gerodontology Society and John Wiley & Sons A/S.)

The aim of this study was to radiographically analyse long-term changes in (i) overeruption of unopposed molars and (ii) tipping of molars with a mesial edentulous space, and whether there is an interaction between the two events. A further aim was to analyse if loss of alveolar bone height might influence overeruption and tipping. The sample consisted of panoramic radiographs taken at an interval of 12 years of 292 subjects from a prospective population study of women. The panoramic radiographs were scanned and analysed. Changes in tipping, overeruption and alveolar bone height of molars and control teeth were measured. The results showed that unopposed molars were more commonly found in the upper jaw and that unopposed molars showed 4·9 times higher risk of overeruption of ≥2 mm (95% CI 1·5-15·3) than opposed molars during the 12-year observation period. The average overeruption for the unopposed molars was 4·5% (s.d. 7·6), which corresponds to approximately 0·9 mm. The degree of overeruption increased with decreased bone support. Molars with a mesial edentulous space were most prevalent in the lower jaw, but neither an edentulous space nor alveolar bone level/bone level change were found to have a significant effect on tipping of the molars. The average mesial tipping was 0·8° (s.d. 5·6). In conclusion, unopposed molars showed a significantly increased risk for overeruption. Molars facing a mesial edentulous space showed a low risk for mesial tipping, but a significant interaction between overeruption and tipping was identified., (© 2011 Blackwell Publishing Ltd.)

The purpose of this study was to develop and report upon a methodology for a non-linear capacity 3D modeling finite element analysis evaluating the loading behavior of different partial denture designs. A 3D finite element model using human CT data was constructed. An original material constant conversion program was implemented in the data simulation of non-linear tissue behavior. The finite element method material properties of residual ridge mucosa were found to have seven material constants and six conversion points of stress values. Periodontal tissues were found to have three constants, and two conversion points. Three magnetic attachment partial denture designs with different bracing elements were evaluated. Technical procedures for finite element model simulation of nonlinear tissue behavior properties evaluating the oral behavior of prosthetic device designs are reported for prosthodontic testing. The use of horizontal cross-arch bracing positively impacts upon the comparative stability of the partial denture designs tested.

The aim of this in vitro study was to investigate the strain distribution of the compressed mandible bone under the applied restoration- removable partial denture and to compare with the same but unrestored mandible under vertical (occlusal) load and to find out whether removable partial denture-restored or unrestored mandible causes greater strain effect on supporting tissue. Four mandible models were tested during loading for the purpose of strain measuring. Digital image correlation system (GOM - German Optical Measuring, Braunschweig, Germany), used for measuring strain consists of two digital cameras and software ARAMIS (6.2.0, Braunschweig, Germany). Remaining teeth suffer from greater strain in the mandible model without removable partial denture (7.5-10%). On the contrary, mandible with removable partial denture shows the maximum strain below the denture saddle (3.5%). However, it can be noticed that the marginal bone of the second lower praemolar in both experimental models is deformed whether the mandible model has (2.8%) or has not (10%) replacement. Within the limitations of this study the higher strain is observed in mandible model without replacement and the strain is limited locally, in the bone region that surrounds remaining teeth and mental foramen.

This study explored the pressure pain threshold (PPT) of the mucosa after tooth extraction. The PPTs of the wounded mucosa of eight volunteer subjects were observed at 7, 30, and 90 days after tooth extraction. The PPTs at 30 days and 90 days were approximately two and three times higher respectively, than those at 7 days. As time passed, the values for the PPTs after tooth extraction increased in all regions. At 90 days after tooth extraction, the PPTs are about 97% recovered compared to the PPTs of the contralateral points.