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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).)

Background: Association of tooth loss and nutritional status has been widely researched with conflicting results. This overview aimed to analyse and summarize findings from systematic reviews on association of tooth loss with nutritional status, in view of their quality assessment and methodological characteristics., Methods: Overview was conducted as per Cochrane Overviews of Reviews guidelines. 5 databases (PubMed, Dentistry and Oral Sciences Source, Scopus, Cochrane Register of Systematic Reviews, Epistemonikos.org) and one online source (Google Scholar) were searched for systematic reviews published between 2010 - July 2022, with inclusion criteria; population: participants aged 18 years or above, intervention/exposure: loss of teeth, comparison: not applicable, outcome: nutritional status, study: systematic reviews and meta-analysis. Reviews on association of prosthetic interventions with nutritional status were not included. Data were extracted for study characteristics, details of primary studies, and main findings. Narrative synthesis of data, overlap of primary studies and quality assessment of studies were done using AMSTAR 2 tool (A Measurement Tool to Assess Systematic Reviews)., Result: Of 1525 articles found, seven systematic reviews were selected (four were systematic reviews, three were systematic reviews with meta-analysis). Five studies showed some or positive association, one found weak association and for one study the association was unclear. Overlap of primary studies was 'very slight'. Meta-analysis of two studies concluded fully or partially edentulous individuals were more likely to be malnourished or at risk of malnutrition, (RR = 1.095, 95% CI 1.007 to 1.190, p = 0.033. RR = 1.22; 95% CI 1.11 to 1.32 p < 0.01), but one found that edentulism was not associated with malnutrition. (RR = 1.072, 95% CI 0.9657-1.200). Quality assessment revealed four studies were 'high', one was 'low' and two were 'critically low.', Conclusion: This overview confirms the association between tooth loss and nutritional status specially in elderly. It is evident that tooth loss increases the likelihood of poor nutritional status. Overall, studies show high heterogeneity in the methodology and quality assessment reveals low confidence in the available evidence. Future studies should use standard assessment tools for tooth loss and nutritional status., (© 2024. The Author(s).)

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Background/objectives: Tooth loss is associated with reduced functional capacity, but so far, there is no relevant causal evidence reported. We investigated the causal effect of tooth loss on the instrumental activities of daily living (IADL) among older adults in England., Design: Natural experiment study with instrumental variable analysis., Setting: The English Longitudinal Study of Aging (ELSA) combined with the participants' childhood exposure to water fluoride due to the community water fluoridation., Participants: Five thousand six hundred and thirty one adults in England born in 1945-1965 participated in the ELSA wave seven survey (conducted in 2014-2015; average age: 61.0 years, 44.6% men)., Measurements: The number of natural teeth predicted by the exogenous geographical and historical variation in exposure to water fluoride from age 5 to 20 years old (instrumental variable) was used as an exposure variable. The outcome, having any limitations in IADL (preparing a hot meal, shopping for groceries, making telephone calls, taking medications, doing work around the house or garden, or managing money), was assessed by self-reported questionnaires., Results: Linear probability model with Two-Stage Least Squares estimation was fitted. Being exposed to fluoridated water was associated with having more natural teeth in later life (coefficient: 0.726; 95% confidence interval (CI) = 0.311, 1.142; F = 11.749). Retaining one more natural tooth reduced the probability of having a limitation in IADL by 3.1 percentage points (coefficient: -0.031; 95% CI = -0.060, -0.002)., Conclusion: Preventing tooth loss maintains functional capacity among older adults in England. Given the high prevalence of tooth loss, this effect is considerable. Further research on the mechanism of the observed causal relationship is needed., (© 2021 The American Geriatrics Society.)

Associations of numbers of teeth present and of missing teeth with Alzheimer's disease were cross-sectionally analyzed using the National Database of Health Insurance Claims and Specific Health Checkups of Japan. Dental care claims data of patients aged 60 years or older diagnosed with periodontitis (n = 4,009,345) or missing teeth (n = 662,182) were used to obtain information about the numbers of teeth present and of missing teeth, respectively, and they were combined with medical care claims data including the diagnosis of Alzheimer's disease. Numbers of teeth present and of missing teeth excluding third molars were calculated using the dental formula in the claims for periodontitis and missing teeth, respectively, and categorized into three groups each. Percentages of subjects treated for Alzheimer's disease with 20-28, 10-19, and 1-9 teeth present were 1.95%, 3.87%, and 6.86%, respectively, in patients diagnosed as having periodontitis, and those treated for Alzheimer's disease with 1-13, 14-27, and 28 missing teeth were 2.67%, 5.51%, and 8.70%, respectively, in patients diagnosed as having missing teeth. Logistic regression models using treatment for Alzheimer's disease as an outcome variable and adjusting for age and sex showed that odds ratios (95% confidence intervals) for patients with 10-19 and 1-9 teeth (reference: 20-28 teeth) were 1.11 (1.10-1.13) and 1.34 (1.32-1.37), respectively, (p<0.001), in patients diagnosed as having periodontitis, and odds ratios (95% confidence intervals) for patients with 14-27 missing teeth and 28 missing teeth (reference: 1-13 missing teeth) were 1.40 (1.36-1.44) and 1.81 (1.74-1.89), respectively, (p<0.001), in patients diagnosed as having missing teeth. In conclusion, the results of the present study using Japanese dental claims data showed that older people visiting dental offices with fewer teeth present and a greater number of missing teeth are more likely to have Alzheimer's disease., Competing Interests: The authors have declared that no competing interests exist.

Objective: The aim of this study was to evaluate the effects of dental status and chewing efficiency on the oral-health-related quality of life (OHRQoL) of nursing-home residents., Materials and Methods: The study was conducted in nine nursing homes. All eligible participants were included, and general and medical data, information about nutritional status and their dental and prosthetic status were collected. Chewing efficiency was assessed by means of a two-colour mixing-ability test. The simple count version of the Geriatric Oral Health Assessment Index (SC-GOHAI) was used to evaluate participants' OHRQoL, and the Mini-Mental State Examination to classify the presence of cognitive impairment. Univariate and multivariate regression models were used to analyse data., Results: The mean age of the participants was 82.1 (± 9.8) years and most participants suffered from at least very mild cognitive impairment. OHRQoL for all participants ( n = 143) and denture wearers only ( n = 105) was substantially associated with the type of prosthesis, the presence of natural teeth, the number of functional occluding pairs and dental and denture-related (if applicable) treatment needs. Furthermore, in both model's univariate analysis showed that chewing efficiency also affected OHRQoL. In contrast, multivariate analysis of all participants revealed that only a higher number of functional occluding pairs (C: 0.250; p < 0.001), fewer dental treatment needs (C: -1.733; p = 0.019) and a better nutritional status (C: -1.298; p = 0.048) were relevant for better OHRQoL. For denture wearers, a higher number of functional occluding pairs (C: 0.192; p = 0.011), a better denture condition (C: -2.194; p = 0.003) and a higher body mass index (BMI) (C: 0.145; p = 0.006) were the main variables associated with better OHRQoL among participants., Conclusion: Good oral health and oral function, including chewing efficiency, are associated with a high OHRQoL of nursing-home residents. However, few dental treatment needs, well-fitting dentures without treatment needs and a high number of functional occluding pairs seem to be the principal variables for an acceptable OHRQoL of nursing-home residents., Competing Interests: The authors declare that they have no conflicts of interest., (© 2020 Zenthöfer et al.)

With population aging, an increasing attention has been paid to quality of life rather than mere longevity. Now, it is urgently needed to clarify predictors of well-being in later life, i.e., "successful aging (SA)." The aim of this study is to investigate whether the number of remaining teeth impacts on maintenance of SA among Japanese older people. The present study was conducted in Tsurugaya district, a suburban area of Sendai, in northern Japan, and included older people aged ≥ 70 years who had met the criteria for SA at a 2003 baseline survey. At the baseline survey, dentists obtained data for the number of remaining teeth. We obtained information about Long-term Care Insurance certification, including the dates of incident functional disability and death between 2003 and 2012. Data pertaining to health-related quality of life (HRQOL) were collected at the 2003 baseline survey and the 2012 follow-up survey. Maintenance of SA was defined in terms of survival, disability-free status and high HRQOL in both 2003 and 2012. Among 450 participants, 108 (24.0%) were considered to have maintained a state of SA. When participants were classified into three groups according to previous studies, in comparison with participants who retained 0-9 teeth, the multivariate prevalence ratios (95% confidence intervals) were 1.39 (0.81-2.36) for those who retained 10-19 teeth and 1.58 (1.002-2.50) for those who retained ≥ 20 teeth (p trend = 0.046). The present results suggest that retaining ≥ 20 teeth is associated with maintenance of SA among Japanese older people.

Background: Orofacial problems present frequently to primary care providers. Many of these problems have a surgical solution. Some may require minor procedures, while others require major maxillofacial surgery., Objective: The purpose of this article is to illustrate how some common orofacial presentations can be investigated and solutions found in conjunction with oral and maxillofacial surgeons., Discussion: This article outlines a method of approach for some of the issues with which patients present to their primary healthcare provider that may be resolved using skills and techniques of maxillofacial surgery.

Background: Hypophosphatasia (HPP) is a rare metabolic bone disorder caused by mutations in the alkaline phosphatase (ALPL) gene, and characterized by low circulating alkaline phosphatase (ALP) levels and bone, muscle, dental and systemic manifestations. In this case series we investigate the clinical spectrum, genetic and biochemical profile of adult HPP patients from the University Hospitals Leuven, Belgium., Methodology: Adults with HPP were identified through medical record review. Inclusion criteria were: (1) age ≥ 16 yr; (2) consecutively low ALP levels not explained by secondary causes; (3) one or more of the following supporting criteria: biochemical evidence of elevated enzyme substrates; subtrochanteric fractures, metatarsal fractures or other typical clinical features; family history of HPP; a known or likely pathogenic ALPL mutation., Results: Nineteen patients met our inclusion criteria (n = 2 infantile, n = 6 childhood, n = 10 adult-onset HPP and one asymptomatic carrier). Fractures and dental abnormalities were the most reported symptoms. Fatigue was reported in n = 7/19 patients (37%), three of which had previously been misdiagnosed as having chronic fatigue syndrome and/or fibromyalgia. Empirical pyridoxine therapy in four patients (without seizures) did not provide symptomatic relief. N = 7/19 patients (37%) were inappropriately treated or planned to be treated with antiresorptive treatment. Two patients developed atypical femoral fractures following exposure to bisphosphonates and/or denosumab. Patients detected by screening were less severely affected, while patients with homozygous or compound heterozygous mutations had the most severe symptoms, significantly lower circulating ALP levels (p = 0.013) and significantly higher pyridoxal-5'-phosphate (p = 0.0018) and urinary phosphoethanolamine (p = 0.0001) concentrations., Conclusions: Screening may detect mainly less severely affected individuals, which may nevertheless avoid misdiagnosis and inappropriate antiresorptive drug exposure. Patients with biallelic mutations had more severe symptoms, significantly lower ALP and higher substrate levels. Whether the latter finding has implications for the classification and treatment of HPP should be investigated further in larger cohorts., (Copyright © 2018 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.)

Background: Amelogenesis imperfecta (AI) is a highly heterogeneous group of hereditary developmental abnormalities which mainly affects the dental enamel during tooth development in terms of its thickness, structure, and composition. It appears both in syndromic as well as non-syndromic forms. In the affected individuals, the enamel is usually thin, soft, rough, brittle, pitted, chipped, and abraded, having reduced functional ability and aesthetics. It leads to severe complications in the patient, like early tooth loss, severe discomfort, pain, dental caries, chewing difficulties, and discoloration of teeth from yellow to yellowish-brown or creamy type. The study aimed to identify the disease-causing variant in a consanguineous family., Methods: We recruited a consanguineous Pashtun family of Pakistani origin. Exome sequencing analysis was followed by Sanger sequencing to identify the pathogenic variant in this family., Results: Clinical analysis revealed hypomaturation AI having generalized yellow-brown or creamy type of discoloration in affected members. We identified a novel nonsense sequence variant c.1192C > T (p.Gln398*) in exon-12 of SLC24A4 by using exome sequencing. Later, its co-segregation within the family was confirmed by Sanger sequencing. The human gene mutation database (HGMD, 2019) has a record of five pathogenic variants in SLC24A4, causing AI phenotype., Conclusion: This nonsense sequence variant c.1192C > T (p.Gln398*) is the sixth disease-causing variant in SLC24A4, which extends its mutation spectrum and confirms the role of this gene in the morphogenesis of human tooth enamel. The identified variant highlights the critical role of SLC24A4 in causing a rare AI type in humans.

Background: The association between dental status and mortality in community-dwelling older adults has been documented by several studies. The aim of this study was to analyze the contribution of self-assessed chewing ability, number of remaining teeth and serum albumin levels to mortality and the interactions between the three factors., Methods: A 20-year follow-up study was conducted with 666 subjects aged 80 years (from 1996 to 2017) who resided in the 8 areas served by one health center in Iwate Prefecture. Health check-ups including physical fitness measurements were conducted at a meeting place or gymnasium. Medical interview and blood sampling were conducted by physician. Oral examination was examined by dentist. The number of remaining teeth, serum albumin levels, and self-assessed chewing ability were used as predictors of mortality., Results: Among the 608 subjects (233 men and 375 women) included in this study, only 12 subjects (1.97%) survived after 20 years of follow-up. For men, dental status and serum levels of albumin were significantly associated with mortality. The hazard ratios of self-assessed chewing ability calculated by item response theory analysis and the inability to chew at least one food adjusted for serum albumin and tooth conditions were statistically significant in men. When adjusted by health status evaluated by blood tests, self-assessed chewing ability was statistically significant in men. According to path analysis, self-assessed chewing ability and serum albumin independently affected mortality in men., Conclusion: Masticatory dysfunction may be an important risk factor for mortality in men, even though it was self-assessed. Retaining chewing ability might be a useful predictor of longevity in older male adults.

Objectives: Tooth loss, closely associated with malnutrition, increases the risk for cardiovascular disease. The aim of this study was to examine the link between tooth loss, nutritional status, and stroke outcomes., Methods: We retrospectively analyzed 195 consecutive patients with acute ischemic stroke who were evaluated for tooth loss. Tooth loss was classified as mild or severe. Nutritional status was evaluated using the Controlling Nutritional Status (CONUT) score. A poor neurologic outcome was defined as a score of 3 to 6 on the modified Rankin Scale at 3 mo post-stroke onset; a score of 0 to 2 was defined as a good outcome., Results: A significant correlation was observed between tooth loss and the CONUT score at admission (ρ = 0.156; P = 0.034). Patients with poor outcomes had higher CONUT scores (P < 0.001) and a greater frequency of severe tooth loss (P = 0.025). On multivariate analysis, severe tooth loss (odds ratio [OR], 3.93; 95% confidence interval [CI], 1.31-11.8) and the CONUT score (OR, 1.33; 95% CI, 1.02-1.74) were independently associated with poor stroke outcomes., Conclusions: Nutritional status was associated with tooth loss among patients with acute ischemic stroke. Severe tooth loss and a higher CONUT score were independently associated with poor stroke outcomes., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:, (Copyright © 2019 Elsevier Inc. All rights reserved.)

Long-term tooth loss is associated with the suppression of hippocampal neurogenesis and impairment of hippocampus-dependent cognition with aging. The morphologic basis of the hippocampal alterations, however, remains unclear. In the present study, we investigated whether tooth loss early in life affects the hippocampal ultrastructure in senescence-accelerated mouse prone 8 (SAMP8) mice, using transmission electron microscopy. Male SAMP8 mice were randomized into control or tooth-loss groups. All maxillary molar teeth were removed at 1 month of age. Hippocampal morphologic alterations were evaluated at 9 months of age. Tooth loss early in life induced mitochondrial damage and lipofuscin accumulation in the hippocampal neurons. A thinner myelin sheath and decreased postsynaptic density length were also observed. Our results revealed that tooth loss early in life may lead to hippocampal ultrastructure remodeling and subsequent hippocampus-dependent cognitive impairment in SAMP8 mice with aging., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Extant baleen whales (Mysticeti) share a distinct suite of extreme and unique adaptations to perform bulk filter feeding, such as a long, arched skull, and mandible and the complete loss of adult dentition in favor of baleen plates. However, mysticetes still develop tooth germs during ontogeny. In the fossil record, multiple groups document the transition from ancestral raptorial feeding to filter feeding. Fetal specimens give us an extraordinary opportunity to observe when and how this macroevolutionary transition occurs during gestation. We used iodine-enhanced and traditional CT scanning to visualize the internal anatomy of five fetuses of humpback whale representing the first two-thirds of gestation, and we combine these data with previously published reports to provide the first comprehensive qualitative description of the sequence of developmental changes that characterize the skull and dentition. We also use quantitative methods based on 3D landmarks to investigate the shape changes in the fetuses in relation to a juvenile cranial morphology. We found similarities in the ossification patterns of the humpback and other cetaceans (dolphins), but there appear to be major differences when comparing them to terrestrial artiodactyls. As for the tooth germs, this developmental sequence confirms that the tooth-to-baleen transition occurs in the last one-third of gestation. Analysis of cranial shape development revealed a progressive elongation of the rostrum and a resulting posterior movement of the nasals relative to the braincase. Future work will involve acquisition of data from other species to complete our documentation of the teeth-to-baleen transition. Anat Rec, 2018. © 2018 American Association for Anatomy., (© 2018 American Association for Anatomy.)

Purpose of the Review: Epidemiological surveillance documents an escalating epidemic prevalence of both type 2 diabetes (T2DM) and periodontal disease (PD). The principal goals of this review are to: 1) re-examine the clinical significance of associations between PD and T2DM, based on strength of collective evidence as determined by systematic review and meta-analysis, and 2) review findings of the systematic reviews and meta-analyses in light of the current understanding of PD-associated pathophysiology and intersection with T2DM pathophysiology., Recent Findings: Tooth loss predicts risk for chronic disease and mortality. PD is significantly associated with complications of diabetes, including retinopathy. Based on systematic reviews and meta-analyses, the adjunctive use of certain antibiotics enhances non-surgical periodontal treatment (NSPT) in patients with T2DM. Systematic reviews and meta-analyses support NSPT efficacy in achieving metabolic control. Systematic reviews and meta-analyses support the association between PD and T2DM, albeit the effect size may be modest. PD-T2DM interactions have important clinical implications.

Chewing ability is essential to maintain nutrition status and can be associated with oral conditions, sarcopenia, and lung function in patients with chronic obstructive pulmonary disease (COPD). Herein, our pilot study investigated the chewing ability and degree of desaturation during chewing in patients with COPD (n = 41) and control subjects (n = 22). Subjects chewed a color-changing chewing gum for 1 minute and chewing ability was assessed by the color of the chewed gum, which was scored from 1 (very poor) to 5 (very good). Arterial oxygen saturation (SpO2) was monitored using a pulse oximeter and the difference in SpO2 was determined by comparison between before and during chewing. The mean color score of the chewed gum was lower in the COPD group than in the control group (3.1±0.7 vs 4.2±0.9, p<0.0001). Muscle mass loss (p<0.05), <20 remaining teeth (p<0.005), and COPD (p<0.001) were risk factors for poor chewing ability. The mean SpO2 decreased by 0.78±1.46% during gum chewing for 1 min. The mean SpO2 during gum chewing (95.1±2.4%) was lower than before gum chewing (95.9±1.7%) (p<0.05). The reduction of SpO2 was greater in COPD patients who had fewer remaining teeth (p<0.05). COPD patients with SpO2 reduction >4% during the 6-minute walk test showed greater reduction during gum chewing (p<0.05). Our results suggest that COPD patients with fewer remaining teeth exhibit poor chewing ability and greater desaturation during chewing.

This study investigated whether periodontitis affects systemic bone status and whether FRAX® is a screening tool for periodontal disease in elderly women. The findings showed that bone density was not influenced by periodontitis and highlighted that women with FRAX® score above the intervention threshold had greater chance to present severe periodontitis., Purpose: This study investigated whether periodontal disease is a predictor for systemic bone loss among elderly women. The utilization of FRAX® as a screening tool for severe periodontitis was also evaluated in this population., Methods: Current bone mineral density (BMD) for lumbar spine and proximal femur was used as an indicator of "bone status." Number of interdental sites with severe clinical attachment loss, frequency of bleeding on probing, and percentage of tooth loss due to periodontitis represented "periodontal disease" that was tested as a predictor of bone loss in a structural equation modeling analysis involving 110 participants. The intake of antiosteoporosis medication was considered in the analysis. Four other different criteria for periodontitis classification were also tested. FRAX® for major fracture was calculated without BMD, and with intervention threshold set by age. Longitudinally, BMD changes up to 10 years were also obtained and checked for possible association with periodontitis., Results: Periodontal disease was not a predictor for worse systemic bone status according to the different periodontal disease classifications, and was not associated with BMD changes. Antiosteoporosis medication directly predicted periodontal disease and systemic bone status. Women with FRAX® score above the intervention threshold had higher chance for periodontitis in more advanced stages: III/IV (OR = 1.13, 95% CI [1.04 to 1.22], p = 0.03)., Conclusion: Periodontal disease did not constitute a predictor for reduced systemic bone density in the studied population of elderly women. On the other hand, FRAX® demonstrated to be a useful tool to suggest periodontal evaluation. Antiresorptive medication showed benefits on periodontal and bone status.

Background: Low masticatory ability and the resulting decrease in intake of masticable foods can result in undernutrition. The present study investigated the relationship between tooth loss, low masticatory ability, and nutritional indices in the elderly., Methods: The data analyzed in this study were retrieved from the baseline data of the 2007 Fujiwara-kyo study, a prospective cohort study of community-dwelling elderly individuals. Subjects included 1591 men and 1543 women, both with a median age of 71 years. The maximum occlusal force was measured as an objective index of masticatory ability. Foods were divided into five groups based on hardness: Group 1 (bananas, etc.), 0.53 kg; Group 2 (boiled rice, etc.), 1.22 kg; Group 3 (raisins, etc.), 2.93 kg; Group 4 (raw carrots, etc.), 4.38 kg; and Group 5 (beef jerky), 6.56 kg. To obtain a subjective index of masticatory ability, a questionnaire-based survey was conducted to determine whether subjects could masticate foods within each group. As nutritional indices, serum albumin levels and body mass index (BMI) data were used., Results: The median number of teeth was 21. The proportion of subjects for whom all five food groups were masticable showed a significant decrease in the number of teeth in both males and females. Logistic regression analysis showed that, after adjustment for confounders, no significant relationships were observed between the number of teeth and the masticatory ability with nutritional indices in males. In females, a maximum occlusal force of 100 to 300 N (OR = 1.65; 95% CI = 1.06-2.55) or less than 100 N (OR = 1.95; 95% CI = 1.15-3.31) showed a significant correlation with serum albumin levels below 4.4 g/dL (reference: 500 N or more). In addition, the masticability of all five food groups showed a significant correlation with BMI < 21.0 kg/m 2 (OR = 0.62; 95% CI = 0.46-0.85) in females., Conclusions: A low number of teeth was associated with low masticatory ability in both males and females. Low masticatory ability was associated with low plasma albumin levels and low BMI in females. Not smoking, maintaining grip strength, preventing cancer, and masticatory ability are important for preventing undernutrition.

Background: Studies on the elderly have reported that the risk of cognitive impairment is affected by chewing difficulty., Objective: To determine whether there is a relationship between the number of pairs of antagonist teeth that come into contact when the mouth is closed (functional masticatory units [FMUs]) and the level of cognitive impairment., Methods: We conducted a cross-sectional observational study with 502 institutionalised White individuals older than 65 years, living in the northwest of Spain and Portugal. Through a direct visual inspection, we recorded the number of FMUs. Cognitive impairment was assessed by applying the Mini-Cognitive Examination (MCE), a test derived from the Mini-Mental State Examination. To describe the statistical relationship between the FMUs and the MCE values, a generalised linear model (GLM) was applied. We assessed the GLM predictive capacity for detecting cognitive impairment (MCE ≤23) in a new study group consisting of 156 elderly individuals., Results: A large number of FMUs was significantly associated with a lower probability of cognitive impairment, regardless of the nature of the contact and its location (explained deviance, 30.1%). The model's discriminatory capacity for cognitive impairment based on the FMUs was "good" (0.820). The model's predictive capacity for cognitive impairment was "acceptable" (sensitivity, 0.786; positive predictive value, 0.900; accuracy, 0.729)., Conclusion: In White, elderly institutionalised individuals, the absolute number of FMUs is significantly related to their MCE scores., (© 2019 John Wiley & Sons Ltd.)

Smoking is a leading cause of preventable death. The effect of tobacco is even more contundent in people with mental illness and, in general, cigarette smoking addiction is influenced by genetic factors. The opioid system is involved in the mesolimbic reward system, which is of great importance in addictive behaviors, such as smoking and is influenced by genes such as the OPRM1. The aim of this study was to evaluate if selecting a comparison group that include light smokers versus people that never smoked impacts the results of genetic association studies. In addition, to evaluate the genetic association in different groups of smokers by analyzing independent covariates such as mental illness and clinical dental data. All subjects were participants of the Dental Registry and DNA Repository project. Genotyping was carried out using TaqMan chemistry for two markers in OPRM1 (rs553202 and rs7755635). Logistic regression analyses were performed as implemented in PLINK. The established value for alpha was 5%, and the Hardy-Weinberg equilibrium was evaluated by the chi-square test with one degree of freedom for each marker. 1,897 patients were included, which were allocated to eight distinct groups, according to the frequency and quantity of cigarettes smoked and mental illness status. There was no significant association between the two markers in OPRM1 and smoking. When mental illness and dental clinical data (tooth loss, dental caries, and periodontitis) were used as covariates, there were associations between heavy smoking and OPRM1, when non-smokers were used as comparison. We did not have diet or microbiome data to consider for these dental analyses and suggest that these kinds of data should be always incorporated in the future. Significant results were found only when the covariables mental illness and oral clinical data were added to the analysis., Competing Interests: The authors have declared that no competing interests exist.

Objective: To describe the methodological aspects of a Prospective Cohort Study of adult oral health in Piracicaba, Brazil., Results: This Prospective Cohort Study evaluated adults (20-64 years old) between the years of 2011 and 2015, in Piracicaba, São Paulo, Brazil. The main objective was to evaluate the risk factors for tooth loss in adults. Data were collected at households and selected via probabilistic sampling, through clinical examination of caries, considering as variables the decayed, missing and filled permanent teeth index, need for caries treatment, periodontal disease (Community Periodontal Index and Periodontal Attachment Loss), use and need for dental prosthesis, and presence of visible biofilm. A questionnaire about demographic, socioeconomic and health habits, use of dental services, self-perceived quality of life (Oral Health Impact Profile-14) and health literacy (14-item Health Literacy Scale) was also employed. In 2011, 248 adults participated, and in 2015, 143 (follow-up rate = 57.7%). Despite the follow-up sample loss, most sociodemographic characteristics remained in the participant sample: for example, women (72.0%) (p = 0.534), family income between R$545,00 and R$1090,00 (63.9%) (p = 0.920), above 11 years of education (53.1%) (p = 0.200) and belonging to middle class (67.1%) (p = 0.909).

Objectives: To quantify the patient-reported effect of oral rehabilitation and investigate aspects associated with this., Methods: The patient-reported effect in participants treated with fixed dental prosthesis (FDP; n = 72) or removable dental prosthesis (RDP; n = 58) was measured using the Oral Health Impact Profile 14 (OHIP-14) and global oral ratings (GOR) of aesthetics, chewing and comfort before and after treatment and global transition judgements (GTJ) of aesthetics, chewing and comfort after treatment. Explanatory variables included gender, age, if a prosthetic replacement was present before treatment, type of prosthetic treatment performed, number of teeth replaced and zone of the teeth replaced., Results: The RDP and FDP treatments both significantly improved the OHIP-14 score with a moderate to large effect and most participants had good patient-reported effect. The effect varied depending on the method used. In the bivariate analyses, the number of participants with good effect was higher in the RDP group than the FDP group when using the OHIP-14 and GOR whereas the effect was higher in the FDP group when using the GTJ. Multiple regression analyses showed that poor chewing ability before treatment was associated with good effect measured by the OHIP-14 and GOR and that poor effect in chewing ability and RDP treatment was associated with poor effect in comfort measured by GTJ. Functional problems after treatment were associated with no/poor effect., Conclusions: Oral rehabilitation with fixed or removable prostheses in general yields good patient-reported effect. Masticatory aspects highly influence the patient-reported effect and treatment with RDP is associated with poor effect in oral comfort., (© 2018 John Wiley & Sons Ltd.)

Background: The tongue is responsible for compressing food against the palate and squeezing it into the pharynx during the oral preparatory phase of swallowing. Tongue pressure (TP), an indicator of tongue muscle strength, has been observed to decline with age; maximum occlusal force (MOF), an indicator of chewing ability, is correlated with TP. However, no study has investigated the relationship between TP and MOF., Objective: To investigate the correlation between TP and MOF according to age in healthy individuals., Methods: We retrospectively collected handgrip strength (HGS), body mass index (BMI), TP, MOF and tooth loss data for 785 healthy participants (305 men, 480 women). All subjects had either unilateral or bilateral occlusal support, regardless of the presence of dentures or natural teeth. The participants were divided into two groups: an adult (20s-50s, n = 497) group and an elderly (60s-80s, n = 288) group. Multivariate linear regression analysis was performed to determine significant independent variables associated with TP in both groups., Results: Multivariate analysis revealed that TP was significantly associated with age (β = -0.153), BMI (β = 0.205), HGS (β = 0.298) and MOF (β = 0.239) in the adult group (all P < 0.001) and with age (β = -0.266, P < 0.001), BMI (β = 0.160, P = 0.005), MOF (β = 0.217, P = 0.001) and tooth loss (β = 0.156, P = 0.011) in the elderly group., Conclusions: As age and MOF are each associated with TP in both elderly and adult patients, age-related TP decline can be prevented with routine lingual exercises, even before the onset of old age. Additionally, MOF deterioration may indicate a decline in TP for elderly., (© 2018 John Wiley & Sons Ltd.)

Objectives: The aim of this study was to examine and compare the oral function of older people with mild cognitive impairment (MCI) or dementia., Methods: This cross-sectional observational study included participants with MCI or dementia aged 60 years or older. Global cognitive functioning was evaluated with the Mini Mental State Examination (MMSE) and the oral function was evaluated with subjective and objective assessments, including the perceived quality of chewing and swallowing, the function of the prostheses, the number of occluding pairs (OP), the degree of tooth wear and the active and passive maximum mouth opening., Results: The quality of chewing and swallowing was perceived as good in, respectively, 86.0% and 90.9% of the participants. Full or partial prostheses were worn by 63.8% of the participants, and the retention was good in 58.4% of the upper and 50.0% of the lower prostheses. Participants with MCI had a median of 3.0 (Inter Quartile Range [IQR] 0.0-7.5) occluding pairs, while participants with dementia had a median of 0.0 (IQR 0.0-1.0) occluding pairs, U = 3838.50, P < 0.001. There was a weak positive correlation between the number of occluding pairs and the MMSE score, r = 0.267, also when adjusted for age, r = 0.230. The median tooth wear score was 2.0 (IQR 2.0-2.0) in participants with MCI or dementia. The active maximum mouth opening was 45.8 (SD 9.3) mm in participants with dementia, while it was 49.8 (SD 8.1) mm in those with MCI, t(253) = 2.67, P = 0.008., Conclusion: For most participants with MCI or dementia, the swallowing ability and chewing ability were perceived as good. In addition, more than half of the prostheses had good retention and occlusion. Participants with more severe cognitive impairment had fewer occluding pairs and a smaller active mouth opening. The degree of tooth wear was less than one-third of the clinical crown in most participants with MCI or dementia., (© 2018 The Authors. Journal of Oral Rehabilitation Published by John Wiley & Sons Ltd.)

Objective To report a case of successful allogeneic grafting of mesenchymal dental pulp stem cells (DPSCs) as preliminary findings in a patient with periodontal disease enrolled into clinical trial ISRCTN12831118. Methods Mesenchymal stem cells from the dental pulp of a deciduous tooth from a 7-year-old donor were separated from the pulp chamber and processed via enzymatic digestion and centrifugation. DPSCs were passaged and cultured on a 35 × 13 mm culture dish in minimum essential medium-alpha, without supplementation. After reaching 80% confluency, 5 x 10 6 allogeneic DPSCs in 250 µl phosphate buffered saline were seeded onto a dry scaffold of lyophilized collagen-polyvinylpyrrolidone sponge placed in the left lower premolar area of a 61-year-old patient with periodontal disease. Surgical access to the lower premolar area was achieved using the flap technique. Results At 3 and 6 months following allogeneic graft, the patient showed no sign of rejection and exhibited decreases in tooth mobility, periodontal pocket depth and bone defect area. Bone mineral density had increased at the graft site. Conclusions Regenerative periodontal therapy using DPSCs of allogeneic origin may be a promising treatment for periodontal disease-induced bone defects.

Background: Socioeconomic status (SES) is associated with systemic disease and influences oral and general health. Several studies have found inequalities associated with oral health and SES. We examined the relationship between tooth loss and SES in Korean adults using data from the 2012-2013 Korean National Health and Nutrition Examination Survey. Methods: A total of 7,005 participants were included in this study. Subjects were divided into two groups depending on their total number of natural teeth: <20 and ≥20. Next, participants were divided into quartiles depending on household income and educational level. Multivariate logistic regression was used to obtain odds ratios (OR) for remaining teeth according to income and education levels., Results: As income and education levels increased, subjects were more likely to have ≥20 remaining teeth (p-value and p-value for trend <0.001), brush their teeth more than three times per day, use extra oral products, and have regular oral-health checkups (all p<0.001). The odds of having ≥20 remaining teeth increased with increases in income and education, after adjusting for all covariates (OR = 1.493 for income Q3, OR = 1.571 for income Q4; OR = 1.763 for 10-12 years education, OR = 2.189 for ≥13years education)., Conclusion: Subjects with higher SES had more remaining teeth than subjects with lower SES. Preserving remaining teeth should be encouraged in subjects with low SES by promoting good oral-health behavior and encouraging more oral-health checkups.

In the last few decades, neurobiological and human brain imaging research have greatly advanced our understanding of brain mechanisms that support perception and memory, as well as their function in daily activities. Knowledge of the neurobiological mechanisms behind the deafferentation of stomatognathic systems has also expanded greatly in recent decades. In particular, current studies reveal that the peripheral deafferentations of stomatognathic systems may be projected globally into the central nervous system (CNS) and become an associated critical factor in triggering and aggravating neurodegenerative diseases. This review explores basic neurobiological mechanisms associated with the deafferentation of stomatognathic systems. Further included is a discussion on tooth loss and other dental deafferentation (DD) mechanisms, with a focus on dental and masticatory apparatuses associated with brain functions and which may underlie the changes observed in the aging brain. A new hypothesis is presented where DD and changes in the functionality of teeth and the masticatory apparatus may cause brain damage as a result of altered cerebral circulation and dysfunctional homeostasis. Furthermore, multiple recurrent reorganizations of the brain may be a triggering or contributing risk factor in the onset and progression of neurodegenerative conditions such as Alzheimer's disease (AD). A growing understanding of the association between DD and brain aging may lead to solutions in treating and preventing cognitive decline and neurodegenerative diseases., (Copyright © 2018. Published by Elsevier Taiwan.)

Tooth loss, decreased mass and strength of the masticatory muscles leading to difficulty in chewing have been suggested as important determinants of eating and nutrition in the elderly. To compensate for the loss of teeth, in particular, a majority of the elderly rely on dental prosthesis for chewing. Chewing function is indeed an important aspect of oral health, and therefore, oral rehabilitation procedures should aim to restore or maintain adequate function. However, even if the possibilities to anatomically restore lost teeth and occlusion have never been better; conventional rehabilitation procedures may still fail to optimally restore oral functions. Perhaps this is due to the lack of focus on the importance of the brain in the rehabilitation procedures. Therefore, the aim of this narrative review was to discuss the importance of maintaining or restoring optimum chewing function in the superageing population and to summarise the emerging studies on oral motor task performance and measures of cortical neuroplasticity induced by systematic training paradigms in healthy participants. Further, brain imaging studies in patients undergoing or undergone oral rehabilitation procedures will be discussed. Overall, this information is believed to enhance the understanding and develop better rehabilitative strategies to exploit training-induced cortical neuroplasticity in individuals affected by impaired oral motor coordination and function. Training or relearning of oral motor tasks could be important to optimise masticatory performance in dental prosthesis users and may represent a much-needed paradigm shift in the approach to oral rehabilitation procedures., (© 2018 John Wiley & Sons Ltd.)

Although several studies have demonstrated a potential correlation of dietary patterns with cognitive function, the relationship between tooth loss and dietary patterns and cognitive function have not been identified. In this cross-sectional study, we used a reduced rank regression (RRR) analysis, a technique used previously to observe dietary patterns based on the intakes of nutrients or levels of biomarkers associated with the condition of interest, to identify tooth loss-related dietary patterns and investigate the associations of such patterns with cognitive impairment in 334 community-dwelling Japanese subjects aged ≥ 60 years. According to Pearson correlation coefficients, the intakes of six nutrients (ash content, sodium, zinc, vitamin B1, α- and β-carotene) correlated significantly with the number of remaining teeth. Using RRR analysis, we extracted four dietary patterns in our subject population that explained 86.67% of the total variation in the intakes of these six nutrients. Particularly, dietary pattern 1 (DP1) accounted for 52.2% of the total variation. Food groups with factor loadings of ≥ 0.2 included pickled green leafy vegetables, lettuce/cabbage, green leaves vegetables, cabbage, carrots/squash; by contrast, rice had a factor loading of <-0.2. In a multivariate regression analysis, the adjusted odds ratios regarding the prevalence of cognitive impairment for the lowest, middle and highest tertiles of the DP1 score were 1.00 (reference), 1.224 (95% confidence interval [CI]: 0.611-2.453) and 0.427 (95% CI: 0.191-0.954), respectively. To our knowledge, this is the first report to show that tooth loss-related dietary patterns are associated with a high prevalence of cognitive impairment. These results may motivate changes in dental treatment and the dietary behaviours and thereby lower the risk of cognitive impairment.

Background: Previous studies have reported a relationship between masseter muscle thickness and tooth loss or limb muscle thickness. However, it is not yet known whether masseter muscle thickness is related to appendicular skeletal muscle mass, and grip strength. The purpose of this study was to determine which of the two variables-tooth loss or appendicular skeletal muscle mass index-is more strongly related to masseter muscle thickness, and to identify a suitable indicator of decreasing masseter muscle thickness in healthy elderly individuals., Methods: Grip strength, walking speed, body weight, skeletal muscle mass index, tooth loss, and masseter muscle thickness at rest and during contraction were determined in 97 community-dwelling elderly individuals aged ≥65 years (men: 44, women: 53). Masseter muscle thickness was chosen as the dependent variable, while age, skeletal muscle mass index, body weight, grip strength, and tooth loss were chosen as the independent variables. Multiple regression analysis was conducted using the stepwise regression method., Results: In men, grip strength was the only independent predictor of masseter muscle thickness at rest. Tooth loss and grip strength were independent predictor of masseter muscle thickness during contraction. In women, tooth loss was the independent predictor of masseter muscle thickness both at rest and during contraction, while grip strength and body weight were the independent predictor of masseter muscle thickness at rest only., Conclusions: We confirmed that in healthy elderly individuals, tooth loss has a stronger relationship with masseter muscle thickness than aging and skeletal muscle mass index do. Masseter muscle thickness in both elderly men and women is also associated with grip strength, suggesting that grip strength can be used as an indicator of masseter muscle thickness in this population.

Background: Aging is associated with a decline in masticatory muscles mass and performance. The present study aims to examine the differences in the cross-sectional areas of the masseter, medial and lateral pterygoid muscles in relation to age and the present dental status in a population-based magnetic resonance imaging study., Methods: This cross sectional study involved 747 subjects aged between 30-89 years (344 male, 403 female) who underwent both a whole body MRI and a full oral examination. The cross-sectional areas of the masseter, medial and lateral pterygoid muscles were measured from MRI images using the software Osirix. Dental and prosthetic status data from the oral examination were classified according to Eichner index. The method of generalized least squares, also called growth curve model, was used to examine the associations between the cross-sectional areas, age and tooth status., Results: The cross-sectional area of the lateral pterygoid muscle decreased substantially with age in women but did not depend on age in men. The medial pterygoid muscle depended on age but an effect modification by gender was uncertain. Masseter muscle was weakly associated with age but strongly associated with the number of teeth in both genders., Conclusions: Our findings suggest that age has a heterogeneous effect on masticatory muscles. This indicates that age related changes to the masticatory muscles are muscle specific and are not consistent between the different muscles., Competing Interests: The authors declare that they have no competing interests

The purpose of this cross-sectional study was to investigate the effect of different forms of periodontal diseases on Oral Health-Related Quality of Life (OHRQoL). Fifty-two patients with Aggressive Periodontitis (AP) or Chronic Periodontitis (CP) were included: nine patients with Localized Aggressive Periodontitis (LAP), thirty-three patients with Generalized Aggressive Periodontitis (GAP) and ten patients with Generalized Chronic Periodontitis (GCP). Oral Health Impact Profile questionnaires (OHIP-14) were distributed after a clinical examination that measured the following periodontal parameters: tooth loss, bleeding on probing (BoP), probing depth (PD), gingival recession (REC) and clinical attachment level (CAL). The global OHIP-14 score means were 10.6 for LAP, 16.5 for GAP, and 17.5 for GCP. A statistically significant difference (p < 0.01) was observed between the LAP group and the other two groups. There was significantly less bleeding and recession in the LAP group than in the patients with the generalized forms of periodontitis. LAP, GAP and GCP have an impact on patient quality of life when measured using the OHIP-14. Patients with GAP and GCP had poorer OHRQoL than LAP patients.

Introduction/objective: A systematic review was conducted to explore whether tooth loss affects dietary intake and nutritional status among adults., Data: Longitudinal studies of population-based or clinical samples of adults exploring the effect of tooth loss on food/dietary/nutrient intake and/or nutritional status were included for consideration. The risk of bias was assessed using the Newcastle-Ottawa Scale for cohort studies., Sources: A search strategy was designed to find published studies on MEDLINE, EMBASE and LILACS up to March 2017., Study Selection: Eight longitudinal studies in 4 countries (United States, Japan, Australia and Brazil) were included. Five of the six studies investigating the association between tooth loss and dietary intake showed significant results. The only consistent association, as reported in 2 studies, was for greater (self-reported) tooth loss and smaller reductions in dietary cholesterol. Three of the 4 studies investigating the association between tooth loss and nutritional status showed significant results. However, most results were contradicting. The quality of the evidence was weak., Conclusion: There is at present no strong evidence on the effect of tooth loss on diet and nutrition, with inconsistent results among the few studies identified. Additional high-quality longitudinal studies should address the limitations of previous studies identified in this review., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

While changes in mandibular shape over time are not widely recognized by skeletal biologists, mandibular remodeling and associated changes in gross morphology may result from a number of causes related to mechanical stress such as antemortem tooth loss, changes in bite force, or alterations of masticatory performance. This study investigated the relationship between age-related changes and antemortem tooth loss in adult humans via dry bone measurements. This study examined 10 standard mandibular measurements as well as individual antemortem tooth loss scores using the Eichner Index from a total of 319 female and male individuals with ages ranging from 16 to 99 years. Results indicate that few mandibular measurements exhibited age-related changes, and most were affected by antemortem tooth loss., (© 2017 American Academy of Forensic Sciences.)

The evolution of filter feeding in baleen whales (Mysticeti) facilitated a wide range of ecological diversity and extreme gigantism. The innovation of filter feeding evolved in a shift from a mineralized upper and lower dentition in stem mysticetes to keratinous baleen plates that hang only from the roof of the mouth in extant species, which are all edentulous as adults. While all extant mysticetes are born with a mandible lacking a specialized feeding structure (i.e., baleen), the bony surface retains small foramina with elongated sulci that often merge together in what has been termed the alveolar gutter. Because mysticete embryos develop tooth buds that resorb in utero, these foramina have been interpreted as homologous to tooth alveoli in other mammals. Here, we test this homology by creating 3D models of the internal mandibular morphology from terrestrial artiodactyls and fossil and extant cetaceans, including stem cetaceans, odontocetes and mysticetes. We demonstrate that dorsal foramina on the mandible communicate with the mandibular canal via smaller canals, which we explain within the context of known mechanical models of bone resorption. We suggest that these dorsal foramina represent distinct branches of the inferior alveolar nerve (or artery), rather than alveoli homologous with those of other mammals. As a functional explanation, we propose that these branches provide sensation to the dorsal margin of the mandible to facilitate placement and occlusion of the baleen plates during filer feeding.

The paper reviews human mastication, focusing on its age-related changes. The first part describes mastication adaptation in young healthy individuals. Adaptation to obtain a food bolus ready to be swallowed relies on variations in number of cycles, muscle strength and volume of emitted saliva. As a result, the food bolus displays granulometric and rheological properties, the values of which are maintained within the adaptive range of deglutition. The second part concerns healthy ageing. Some mastication parameters are slightly modified by age, but ageing itself does not impair mastication, as the adaptation possibilities remain operant. The third part reports on very aged subjects, who display frequent systemic or local diseases. Local and/or general diseases such as tooth loss, salivary defect, or motor impairment are then indistinguishably superimposed on the effects of very old age. The resulting impaired function increases the risk of aspiration and choking. Lastly, the consequences for eating behaviour and nutrition are evoked., (© 2016 John Wiley & Sons Ltd.)

Objective: Tooth loss induced neurological alterations through activation of a stress hormone, corticosterone. Age-related hippocampal morphological and functional changes were accelerated by early tooth loss in senescence-accelerated mouse prone 8 (SAMP8). In order to explore the mechanism underlying the impaired hippocampal function resulting from early masticatory dysfunction due to tooth loss, we investigated the effects of early tooth loss on plasma corticosterone levels, learning ability, neurogenesis, and synaptophysin expression in the hippocampus later in life of SAMP8 mice., Design: We examined the effects of tooth loss soon after tooth eruption (1 month of age) on plasma corticosterone levels, learning ability in the Morris water maze, newborn cell proliferation, survival and differentiation in the hippocampal dentate gyrus, and synaptophysin expression in the hippocampus of aged (8 months of age) SAMP8 mice., Results: Aged mice with early tooth loss exhibited increased plasma corticosterone levels, hippocampus-dependent learning deficits in the Morris water maze, decreased cell proliferation, and cell survival in the dentate gyrus, and suppressed synaptophysin expression in the hippocampus. Newborn cell differentiation in the hippocampal dentate gyrus, however, was not affected by early tooth loss., Conclusion: These findings suggest that learning deficits in aged SAMP8 mice with tooth loss soon after tooth eruption are associated with suppressed neurogenesis and decreased synaptophysin expression resulting from increased plasma corticosterone levels, and that long-term tooth loss leads to impaired cognitive function in older age., (Copyright © 2016. Published by Elsevier Ltd.)

The total number of natural teeth was related to swallowing function among older adults; however, limited information is available regarding the impact of occluding pairs of teeth on swallowing function. This study aimed to examine the association between posterior teeth occlusion and dysphagia risk in older nursing home residents. This cross-sectional study included 238 residents aged ≥60 years from eight nursing homes in Aso City, Japan. Swallowing function was evaluated using the modified water swallowing test (MWST); the primary outcome was dysphagia risk (MWST score ≤3). Posterior teeth occlusion was assessed using number of functional tooth units (FTUs), determined based on number and location of the remaining natural and artificial teeth on implant-supported, fixed or removable prostheses. Univariate and multivariate logistic regression analyses were performed to examine the association between posterior teeth occlusion and dysphagia risk, adjusted for the covariates of number of natural teeth, demographic characteristics, comorbidities, physical function, body mass index and cognitive function. Of the 238 subjects, 44 (18·5%) were determined to be at risk of dysphagia based on the MWST scores. The odds ratio (OR) of dysphagia risk decreased in subjects with higher total FTUs [OR = 0·92, 95% confidence interval (CI) 0·87-0·98]. After adjusting for covariates, this association remained significant (OR = 0·90, 95% CI 0·84-0·97). Loss of posterior teeth occlusion was independently associated with dysphagia risk in older nursing home residents. Maintaining and restoring posterior teeth occlusion may be an effective measure to prevent dysphagia., (© 2016 John Wiley & Sons Ltd.)

Objectives: Cognitive impairment is a common neurological problem in elderly people. In this study, we investigated whether tooth loss, periodontal parameters, and gene variations in the mitochondrial DNA displacement loop region are potential influencing factors on cognitive function., Design: We employed a linear regression model to estimate cross-sectional association between number of teeth lost, periodontal parameters and Mini-mental State Examination score, adjusting for demographic factors, socioeconomic factors, general health status, smoking, drinking, and life habits., Participants: A total of 905 Han Chinese people, ≥50 years of age, with complete data, were enrolled. Blood samples of 567 of the subjects were analyzed for correlation between mitochondrial DNA variants and Mini-mental State Examination score., Results: The number of teeth lost (β = -0.042, 95% CI: -0.061, -0.024, P < 0.001), two single nucleotide polymorphism (SNP) points: A189G (β = -1.540, 95% CI: -2.818, -0.263, P = 0.018) and A16164G (β = -1.053, 95% CI: -2.054, -0.052, P = 0.039) in the mitochondrial DNA displacement loop region, and haplogroup Y (β = -2.152, 95% CI: -4.062, -0.242, P = 0.027) were found to be negatively associated with Mini-mental State Examination scores in the fully adjusted model. No correlation was found between periodontal parameters and Mini-mental State Examination scores., Conclusion: Number of teeth lost, mitochondrial SNPs, and haplogroup Y were correlated with cognitive function in this study population., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The purpose of the present study was to investigate the association between the number of natural teeth and measures of kidney dysfunction, such as urinary albumin/creatinine ratio (ACR) and estimated glomerular filtration (eGFR) rate, using nationally representative data.The data used were from the Korea National Health and Nutrition Examination Survey with cross-sectional design, which was conducted between 2011 and 2012; the sample analyzed in this study consisted of a total of 10,388 respondents, each of whom was 19 years or older and had no missing outcome variables. The association between the number of natural teeth and kidney function was assessed by multiple logistic regression and model was adjusted for age, sex, waist conference, smoking, drinking, exercise, education, income, frequency of tooth brushing per day, diabetes, metabolic syndrome, urinary ACR, and eGFR.The mean age, body mass index, and waist circumference were significantly higher among those with lower kidney function (urinary ACR ≥30 mg/g and eGFR <60 mL/min/1.73m). Urinary ACR and eGFR were associated with loss of natural teeth. As urinary ACR increased, the number of natural teeth decreased accordingly. Conversely, the number of natural teeth increased with an increase in eGFR.This study showed that the number of natural teeth is inversely associated with the presence of kidney disease. Severity of tooth loss may be considered an independent risk indicator for kidney disease among Koreans. More epidemiological studies are warranted to investigate the role of tooth loss in kidney disease, to confirm this relationship and to test possible underlying mechanisms.

Purpose: The aim of this study was to reveal whether the differences in further loss of teeth and occlusal supports, and change in masticatory ability depend on the status of dentition at the age of 70 in community-dwelling elderly people., Methods: A 10-year longitudinal survey was carried out on 349 (176 females and 173 males) elderly subjects. The subjects to be analyzed were classified into four groups in accordance with the classifications of Miyachi's Triangular Classification. Zone A: subjects with ten or more occlusal supports. Zone B: those with nine to five occlusal supports. Zone D: those with four or fewer occlusal supports and 11 or more remaining teeth. Zone C: those with ten or fewer remaining teeth. The numbers of remaining teeth and occlusal supports were recorded in both examinations. Questionnaires regarding their food intake status were given to subjects., Results: Subjects in Zone B had greater numbers of teeth loss than those in Zones A and C. Subjects in Zone B and D lost greater numbers of occlusal supports than subjects in Zones A and C. The number of food items that could be chewed had significantly decreased in subjects who remained in Zone A and those who changed from Zone B to Zones D and C., Conclusions: It was shown that various states of dentition classified by Miyachi's Triangular Classification at the age of 70 resulted in different numbers of remaining teeth and occlusal supports and changes in masticatory ability 10 years later in community-dwelling elderly people., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Facial skeletal asymmetry is commonly found in humans and its main characteristic is menton deviation. The literature suggests that occlusal and masticatory problems arising from tooth absence could be related to the development of such asymmetries., Objective: The aim of this cross-sectional study was to estimate the prevalence of mandibular skeletal asymmetries and to investigate its association with posterior tooth absences., Methods: Tomographic images of 952 individuals aged from 18 to 75 years old were used. Asymmetry was the analyzed outcome, and it was categorized into three groups according to gnathion displacement in relation to the midsagittal plane (relative symmetry, moderate asymmetry, and severe asymmetry). Patients were sorted by the presence of all posterior teeth, unilateral posterior tooth absence, or bilateral posterior tooth absence. Chi-square test with a significance level of 5% was used to verify the association between posterior tooth absence and asymmetry., Results: Results show relative symmetry present in 55.3% of the sample, as well as the prevalence of 27.3% for moderate mandibular asymmetry and 17.4% for severe asymmetry. Moderate and severe mandibular asymmetries occurred in a higher proportion in patients with unilateral posterior tooth absence. However, there was no statistically significant difference between the analyzed groups (p = 0.691)., Conclusions: In this study, mandibular asymmetries did not present any association with the absence of teeth on the posterior area of the arch.

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.)

Several studies have demonstrated that chewing can be regarded as a preventive measure for cognitive impairment, whereas masticatory deficiency, associated with soft-diet feeding, is a risk factor for the development of dementia. At present the link between orofacial sensorimotor activity and cognitive functions is unknown. In subjects with unilateral molar loss we have shown asymmetries in both pupil size and masticatory muscles electromyographic (EMG) activity during clenching: the molar less side was characterized by a lower EMG activity and a smaller pupil. Since implant-prostheses, greatly reduced both the asymmetry in EMG activity and in pupil's size, trigeminal unbalance, leading to unbalance in the activity of the Locus Coeruleus (LC), may be responsible for the pupil's asymmetry. According to the findings obtained in animal models, we propose that the different activity of the right and left LC may induce an asymmetry in brain activity, thus leading to cognitive impairment. According to this hypothesis, prostheses improved the performance in a complex sensorimotor task and increased the mydriasis associated with haptic tasks. In conclusion, the present study indicates that the implant-prosthesis therapy, which reduces the unbalance of trigeminal proprioceptive afferents and the asymmetry in pupil's size, may improve arousal, boosting performance in a complex sensorimotor task.

Background and Objective: Teeth are crucial, not only for mastication, but for overall nutrition and general health, including cognitive function. Aged mice with chronic stress due to tooth loss exhibit impaired hippocampus-dependent learning and memory. Exposure to an enriched environment restores the reduced hippocampal function. Here, we explored the effects of an enriched environment on learning deficits and hippocampal morphologic changes in aged senescence-accelerated mouse strain P8 (SAMP8) mice with tooth loss., Design: Eight-month-old male aged SAMP8 mice with molar intact or with molars removed were housed in either a standard environment or enriched environment for 3 weeks. The Morris water maze was performed for spatial memory test. The newborn cell proliferation, survival, and differentiation in the hippocampus were analyzed using 5-Bromodeoxyuridine (BrdU) immunohistochemical method. The hippocampal brain-derived neurotrophic factor (BDNF) levels were also measured., Results: Mice with upper molars removed (molarless) exhibited a significant decline in the proliferation and survival of newborn cells in the dentate gyrus (DG) as well as in hippocampal BDNF levels. In addition, neuronal differentiation of newly generated cells was suppressed and hippocampus-dependent spatial memory was impaired. Exposure of molarless mice to an enriched environment attenuated the reductions in the hippocampal BDNF levels and neuronal differentiation, and partially improved the proliferation and survival of newborn cells, as well as the spatial memory ability., Conclusion: These findings indicated that an enriched environment could ameliorate the hippocampus-dependent spatial memory impairment induced by molar tooth loss., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Potential associations between oral health and respiratory disease, including chronic obstructive pulmonary disease (COPD), have been suggested in several studies. Among the indicators reflecting oral health, the number of natural teeth is an integrated and simple index to assess in the clinic. In this study, we examined the relationship between the number of natural teeth and airflow obstruction, which is a central feature of COPD., Methods: A total of 3,089 participants over 40 years, who underwent reliable spirometry and oral health assessments were selected from the Korean National Health and Nutrition Examination Survey 2012, a cross-sectional and nationally representative survey. Spirometry results were classified as normal, restrictive, or obstructive pattern. Total number and pairs of natural teeth were counted after excluding third molars., Results: After adjusting for other variables, such as age, body mass index, socioeconomic factors, and oral health factors, the group with airflow obstruction showed significantly fewer natural teeth than the other groups in males (P=0.014 and 0.008 for total number and total pairs of natural teeth, respectively). Compared with participants with full dentition, the adjusted odds ratio for airflow obstruction in males with fewer than 20 natural teeth was 4.18 (95% confidence interval: 2.06-8.49) and with fewer than 10 pairs of natural teeth was 4.74 (95% confidence interval: 2.34-9.62). However, there was no significant association between the total number or pairs of natural teeth and airflow obstruction after adjustment in females., Conclusions: Loss of natural teeth was significantly associated with the presence of airflow obstruction in males. Our finding suggests that the number of natural teeth could be one of the available indices for obstructive lung diseases, including COPD.

Objective: To investigate the effects of tooth loss on gait stability in a healthy elderly population., Methods: A case-control study was conducted among healthy and prosthetically well-restored seniors over the age of 65 years. The test group comprised 24 edentulous participants who were restored with complete dentures in the upper jaw and an overdenture fixed on two implants in the lower jaw. The control group comprised 25 dentate participants who either still had their natural teeth or were restored with conventional fixed partial dentures. Gait stability was evaluated by measuring the parameters 'gait velocity' and 'cycle-time variability' during self-selected normal walking speed and under dual-task performance conditions. Measurements were conducted using the GAITRite(®) electronic walkway system., Results: Dentated and fixed restored participants (the control group) had a significantly higher gait velocity compared with denture wearers (the test group) under both normal walking (p = 0.03) and dual-task performance conditions (p = 0.01). In each test condition, among edentulous participants, gait velocity did not significantly differ according to whether the participant wore their dentures., Conclusion: The present results suggest that tooth loss in healthy seniors is associated with lower gait velocity and therefore may have a negative impact on gait stability., (© 2014 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons Ltd.)

Tooth loss is common, and exploring the neuroplastic capacity of the face primary motor cortex (face-M1) and adjacent primary somatosensory cortex (face-S1) is crucial for understanding how subjects adapt to tooth loss and their prosthetic replacement. The aim was to test if functional reorganization of jaw and tongue motor representations in the rat face-M1 and face-S1 occurs following tooth extraction, and if subsequent dental implant placement can reverse this neuroplasticity. Rats (n = 22) had the right maxillary molar teeth extracted under local and general anesthesia. One month later, seven rats had dental implant placement into healed extraction sites. Naive rats (n = 8) received no surgical treatment. Intracortical microstimulation (ICMS) and recording of evoked jaw and tongue electromyographic responses were used to define jaw and tongue motor representations at 1 month (n = 8) or 2 months (n = 7) postextraction, 1 month postimplant placement, and at 1-2 months in naive rats. There were no significant differences across study groups in the onset latencies of the ICMS-evoked responses (P > 0.05), but in comparison with naive rats, tooth extraction caused a significant (P < 0.05) and sustained (1-2 months) decreased number of ICMS-defined jaw and tongue sites within face-M1 and -S1, and increased thresholds of ICMS-evoked responses in these sites. Furthermore, dental implant placement reversed the extraction-induced changes in face-S1, and in face-M1 the number of jaw sites even increased as compared to naive rats. These novel findings suggest that face-M1 and adjacent face-S1 may play a role in adaptive mechanisms related to tooth loss and their replacement with dental implants., (© 2015 Wiley Periodicals, Inc.)

Edentulous orofacial dyskinesia is a rare condition, characterized by involuntary rhythmic movements of the mandible and presents an embarrassing situation for the patient. Edentulism has been considered as one of the proponents of these irregular movements, and rehabilitation of these patients with complete denture-fabrication using traditional technique restores the masticatory inefficiency and the esthetic component of the patient. Surprisingly, these movements disappear during the clinical steps of complete denture-fabrication and upon insertion of the dentures. Disturbances in the proprioception following loss of tooth may be a contributory factor for edentulous dyskinesia.