Tooth loss is associated with severe cognitive impairment among older people: findings from a population-based study in Brazil

Improving oral hygiene for better cognitive health: Interrelationships of oral hygiene habits, oral health status, and cognitive function in older adults

OBJECTIVES

To explore the interrelationships between oral hygiene habits, oral health status and cognitive function in older adults.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

A total of 371 participants (age 76.79 [7.99] years) were enrolled from June 2020 to November 2021 in an aged care facility.

METHODS

Cognitive function was screened using the mini-mental state examination (MMSE) with adjusted cut-off points for age and education. Periodontal status (Biofilm-Gingival Interface index based on periodontal probing depth and bleeding on probing), dental status (plaque, calculus, and caries), and tooth loss were assessed through full-mouth examination. Oral hygiene habits were based on self- or informant-reporting.

RESULTS

Poor periodontal status was an associated factor for MCI (OR = 2.89, 95% CI = 1.20-6.95), while multiple tooth loss (OR = 4.90, 95% CI = 1.06 ~ 22.59), brushing teeth less than once a day (OR = 2.88, 95% CI = 1.12 ~ 7.45) and delayed dental visits (OR = 2.45, 95% CI = 1.05 ~ 5.68) were associated factors for cognitive impairment. An indirect effect of brushing teeth ≥2 daily on MMSE score through periodontal status was observed only in older adults without cognitive impairment (Bootstrap-corrected B = 0.17, 95%CI = 0.03 ~ 0.36, SE = 0.08, β = 0.08).

CONCLUSIONS AND IMPLICATIONS

Adequate toothbrushing might prevent cognitive decline indirectly by improving periodontal health only in older adults without cognitive impairment. Multiple tooth loss, infrequent toothbrushing, and delayed dental visits were associated factors for cognitive impairment. Nursing professionals and health care policymakers should advocate for the improvement of basic oral hygiene in older adults, and provide regular professional oral hygiene care for older adults with cognitive impairment.

PATIENT OR PUBLIC CONTRIBUTION

The information on oral health habits of this study was based on an interview with the participants or their caregivers during the study period.

Does the Loss of Teeth Have an Impact on Geriatric Patients’ Cognitive Status?

Significant changes in the microstructure of the brain cause dementia and other mental declines associated with aging and disease. Although research has established a connection between oral health and dementia, the underlying pathologic mechanisms are still unknown. Aim: Our aim was to evaluate dentures’ impact on the cognitive state of geriatric patients. Material and methods: A total of 108 individuals seeking treatment at the Faculty of Dental Medicine in Iasi, Romania, participated in the study, which ran from May 2022 to October 2022. Cognitive dysfunction was assessed using the Mini-Mental State Examination. The acquired data were analyzed with IBM SPSS 26.0, and the p-value was set at 0.05. Results: The average value of the MMSE score was 21.81 ± 3.872. Differences between groups of wearer/non-wearer subjects were statistically significant for most of the questions in the questionnaire. Linear regression analysis showed that individuals with a high MMSE score have prosthodontic treatment. A decrease in the MMSE score is associated with a decrease in masticatory efficiency (B = 1.513, p = 0.268). Conclusions: This study provides further evidence that tooth loss is associated with worse cognitive performance. It is thus conceivable that the necessary effects can be achieved by increasing the efforts dedicated to preventing tooth loss in the adult population.

Tooth retention, health, and quality of life in older adults: a scoping review

OBJECTIVE

This scoping review describes the relationship between tooth retention, health, and quality of life in older adults.

METHODS

Seven databases were searched for English language articles for subjects ≥ 65 y from 1981 to 2021. Exposure was tooth retention (≥ 20), and outcomes were general/systemic health and quality of life. Methodological quality was assessed using the Newcastle-Ottawa Scale and Cochrane Risk of Bias 2.0 tool.

RESULTS

140 articles were included, only four were randomized trials. Inter-rater agreement (κ) regarding study inclusion was 0.924. Most were assessed with low risk of bias (n = 103) and of good quality (n = 96). Most studies were conducted in Japan (n = 60) and Europe (n = 51) and only nine in the US. Tooth retention was referred to as "functional dentition" in 132 studies and "shortened dental arch" in 19 studies. Study outcomes were broadly synthesized as (1) cognitive decline/functional dependence, (2) health status/chronic diseases, (3) nutrition, and (4) quality of life.

DISCUSSION

There is a positive relationship between tooth retention, overall health, and quality of life. Older adults retaining ≥ 20 teeth are less likely to experience poorer health. Having < 20 teeth increases the likelihood for functional dependence and onset of disability, and may affect successful ageing. This review supports the general finding that the more teeth older adults retain as they age, the less likely they are to have adverse health outcomes. However, significant knowledge gaps remain which can limit decision-making affecting successful ageing for many older adults. This review highlights the need to consider, as an important marker of oral health and function, the retention of a functional minimum of a natural dentition, rather than a simple numeric score of missing teeth.

The Effect of a Masticatory Muscle Training Program on Chewing Efficiency and Bite Force in People with Dementia

Until now, no study has investigated the effects of masticatory muscle training on chewing function in people with dementia. This study aimed to investigate whether physiotherapeutic exercises for the masticatory muscles have an influence on chewing efficiency and bite force in people with dementia. In a clinical trial with stratified randomization subjects were assigned to three groups based on the Mini Mental State Examination (MMSE: group 1—28–30, group 2—25–27, group 3—18–24). Each group was divided into an experimental (ExpG, intervention) and control group (ConG, no intervention). As intervention a Masticatory Muscle Training (MaMuT) (part 1: three physiotherapeutic treatments and daily home exercises, part 2: daily home exercises only) was carried out. Chewing efficiency and bite force were recorded. The MaMuT influenced the masticatory performance regardless of the cognitive state. Bite force increased in ExpG 1 and 2. Without further training, however, the effect disappeared. Chewing efficiency increased in all ExpG. After completion of the training, the ExpG 2 and 3 showed a decrease to initial values. Subjects of ExpG 1 showed a training effect at the final examination, but a tendency toward the initial values was observed. ExpG 3 seemed to benefit most from the physiotherapeutic exercises in terms of improving chewing efficiency by the end of the intervention phase. ExpG 1 showed the greatest gain in bite force. The MaMuT program is a potential method of improving masticatory performance in people with cognitive impairment or dementia when used on a daily basis.

A prospective association between tooth status and cognitive performance among older adults in Europe

OBJECTIVES

This study set out to examine both the longitudinal association between tooth status and cognitive performance among older adults in Europe, and the mediating effects of loneliness and quality of life on this association.

METHODS

We conducted a prospective analysis using data from 38,614 participants aged 50 or older, taken from the Survey of Health, Ageing and Retirement in Europe (SHARE) of 2013 (baseline) and 2015 (follow up). Bootstrapping with resampling strategies was used for testing a multiple mediator model.

RESULTS

The average age of participants was 66.9 (SD = 9.4). About 23% of the participants had full sets of their own teeth and 38.2% had missing teeth fully replaced by dental implants or dentures. Participants who had partially replaced teeth (B = 0.038, p < 0.001), and with fully replaced teeth (B = 0.041, p < 0.001), or had all their teeth in place (B = 0.055, p < 0.001), had better cognitive performance compared to those who did not replace their missing teeth. It was also found that quality of life and loneliness partially mediated these relationships - Having all teeth in place or replacing all or partially missing teeth was found to affect cognitive performance also via improved quality of life and through lower loneliness.

CONCLUSION

In later life, poor tooth status can be directly associated with cognitive decline and indirectly linked to cognitive performance, in light of decreasing quality of life and increasing loneliness. Clinicians should be aware of both the impact of poor tooth status on cognitive status and the implications for the wellbeing of older adults.

Comparison of the effect of conventional and implant-retained overdentures on brain activity and cognition in a geriatric population - A Functional MRI study

PURPOSE

This study aims to evaluate the effect of rehabilitation with complete dentures versus implant-retained overdenture on activity in various parts of the brain cognition in a geriatric edentulous population via Functional MRI (fMRI) studies and the Mini-Mental State Examination (MMSE).

METHODS

Ten completely edentulous patients were rehabilitated with both complete dentures and two-implant retained overdentures for three months each. fMRI studies were performed for each modality during chewing and recall tasks at three time periods: T0: Completely Edentulous(CE) T1: after three months of wearing Conventional Complete Dentures(CD) and T2: after three months of wearing Implant-retained Overdentures (IOD). The Z scores obtained from the fMRI at these phases of examination were tabulated and correlated with MMSE scores obtained at the corresponding time periods.

RESULTS

Z scores obtained during the memory recall tasks at T2 were the greatest (Prefrontal Cortex (p=0.059) and Hippocampus (p=0.036). The MMSE scores obtained were significantly higher for the IODs when compared to the CDs and Baseline values (p < 0.05)Conclusion: IODs may potentially result in superior sensory feedback in edentulous patients and lead to improved cognitive performance when compared to conventional complete dentures.

Chewing function and related parameters as a function of the degree of dementia: Is there a link between the brain and the mouth?

Background

To date, no study has investigated the association between chewing function and related parameters as a function of the degree of dementia using a finer subdivision of the values of the Mini‐Mental State Examination (MMSE).

Objective

This study aimed to investigate the differences in chewing function and related parameters as a function of the degree of dementia.

Methods

An analysis of cross‐sectional data obtained from the OrBiD (Oral Health, Bite Force, and Dementia) pilot study was performed. The participants were stratified into five groups based on the outcomes of the MMSE (no dementia, MMSE 28–30; mild cognitive impairment, MMSE 25–27; mild dementia, MMSE 18–24; moderate dementia, MMSE 10–17; severe dementia, MMSE <10). The chewing efficiency, maximum occlusal force and related parameters (number of supporting zones, number of teeth, Eichner index, tooth/denture status, denture quality, and dental treatment needs) were recorded.

Results

The MMSE groups showed significantly different chewing efficiencies (p = .003, Jonckheere‐Terpstra test) and maximum occlusal forces (p = .003, Jonckheere‐Terpstra test), but the number of supporting zones (p = .055, chi‐square test) and the number of natural teeth (p = .126, chi‐square test) were not different. The Eichner index, tooth/denture status, denture quality and dental treatment need showed no significant associations with the degree of dementia.

Conclusion

An improvement in the usability of the measurement methods for assessing chewing function in people with dementia is needed. Research involving people with dementia is necessary because the nutritional situation often deteriorates rapidly within a multifactorial system, which includes chewing ability and oral health.

GOHAI and OHIP-EDENT Evaluation in Removable Dental Prostheses Users: Factorial Analysis and Influence of Clinical and Prosthetic Variables

PURPOSE

To assess the degree of satisfaction and quality of life of patients with removable prostheses using the Geriatric Oral Health Assessment Index (GOHAI) and Oral Health Impact Profile in Edentulous Adults (OHIP-EDENT), in addition to evaluating the questionnaires for their validation.

MATERIALS AND METHODS

Eighty patients participated in the study after completing prosthetic rehabilitation treatment. Patients were evaluated using the OHIP-EDENT and GOHAI questionnaires to assess the criteria for quality of life, esthetics, phonetics, masticatory function, stability, comfort, and alteration of taste and pain related to the completed prostheses. The results were subjected to the chi-squared test, Fisher's exact test, and a multinomial logistic regression model, with a significance level of 5%.

RESULTS

The most commonly used removable prosthesis was mandibular removable partial denture (RPD) (n = 43, 53.8%), followed by maxillary RPD (n = 42, 52.5%), maxillary complete denture (CD) (n = 33, 41.3%), and mandibular CD (n = 31, 38.8%). Most patients had to have one (n = 29, 36.3%), two (n = 21, 26.3%), or none (n = 18, 23.8%) adjustments in their prostheses. Five (6.3%) patients' prostheses required three adjustments, and six (7.5%) required four or more adjustments. All reported improvement in esthetics after using the prostheses (p < 0.05). The validation of the questionnaire proved to be more viable when completed without the presence of specific domains.

CONCLUSION

The results of this study indicated that removable prostheses improved the quality of life of rehabilitated patients. The questionnaires used need to be answered and evaluated in their entirety for validation.

Prevalence and Clinical Correlation of Decayed, Missing, and Filled Teeth in Elderly Inpatients With Schizophrenia

Introduction: Schizophrenia is a mental disease with a profound impact on human health. Patients with schizophrenia have poor oral hygiene, increasing their risk of systemic diseases, such as respiratory infections, and declining their quality of life. Therefore, this study aims to assess the oral health status of inpatients with schizophrenia, analyze its related factors, and thus provide scientific evidence for further exploration of corresponding control strategies. Methods: A total of 425 inpatients older than 50 years with a diagnosis of schizophrenia from two psychiatric hospitals (mean age 58.49 ± 5.72 years) were enrolled. The demographic data of the patients were checked on admission. Two independent dentists examined caries, missing teeth, and fillings. Mini-Mental State Examination (MMSE) and Global Deterioration Scale were performed as cognitive tests. Positive and Negative Syndrome Scale and Repeatable Battery for the Assessment of Neuropsychological Status rating scale were used to determine their mental status. Results: The average decayed, missing, and filled teeth index was 12.99 ± 8.86. Linear regression analysis showed that the decayed, missing, and filled teeth index had a significantly positive relationship with age (p < 0.001) and smoking (p < 0.001) and a negative relationship with MMSE (p = 0.029). The missing teeth index had a positive relationship with age (p < 0.001), smoking (p < 0.001), and Global Deterioration Scale (p = 0.014) and a negative relationship with MMSE (p = 0.004). Conclusion: The oral health of elderly patients with schizophrenia is poor, which may be related to the cognitive level of patients and affect their quality of life. The focus should be provided to the oral care of patients with schizophrenia, and investment in their specialized oral treatment should be increased.

Instrumentos de avaliação cognitiva utilizados nos últimos cinco anos em idosos brasileiros

Resumo A detecção e o monitoramento do déficit cognitivo em idosos são necessários já que podem causar impacto em sua funcionalidade. O objetivo dessa revisão integrativa é analisar a produção científica sobre uso de instrumentos de avaliação cognitiva em idosos brasileiros por meio de artigos publicados nos últimos cinco anos, indexados nas bases de dados Web of Science, PubMed, Scopus e Bireme. Os critérios de inclusão foram: artigos originais publicados em inglês e português, de 2012 a 2016, com critério de idade definido para ser considerado idoso, e escore maior que 6 no CASP adaptado. O critério de exclusão foi: ser resumo de congresso. A amostra final foi composta por 100 artigos. Foram apresentados os 61 instrumentos de avaliação cognitiva utilizados nos estudos, com destaque para o Mini Exame do Estado Mental. Essa revisão apresenta o uso de instrumentos cognitivos na pesquisa brasileira, suas diferentes versões e quais domínios são avaliados. O número de instrumentos presentes na literatura foi amplo. Os mais utilizados foram o MEEM (versão de Brucki e colaboradores), o Teste de Fluência Verbal (categoria animais) e o Teste Span de dígitos (ordem direta e inversa). Os achados apresentados nessa revisão são relevantes não apenas para área da pesquisa observacional e experimental, mas também para a prática clínica.

The effect of missing teeth on dementia in older people: a nationwide population-based cohort study in South Korea

Background

To determine the effect of missing teeth on the risk of dementia onset among individuals who received tooth extractions and those who did not, based on the number of missing teeth.

Methods

We selected individuals who had not been diagnosed or treated for dementia between 2002 to 2011 from the National Health Insurance Service-Elderly Cohort Database (NHIS-ECD). We divided participants into two cohorts, a tooth extraction and non-extraction cohort, based on tooth loss from 2002 to 2011. After propensity score matching, there were 104,903 individuals in each cohort, and we included a total of 209,806 individuals in this study. Each cohort was grouped by sex, age, residential area, health insurance eligibility, income level, history of dental caries, history of periodontal treatment, and number of extracted teeth. We analyzed the relationship between dementia onset and these variables using logistic regression analysis.

Results

Individuals with tooth loss had a higher risk for dementia than those without tooth loss (odds ratio [OR] = 1.18; 95% confidence interval [CI]: 1.146–1.215). Regarding the incidence of dementia, the OR increased as the number of missing teeth and age increased, and the OR was higher for women (OR = 1.33; 95% CI: 1.286–1.367) than for men, and this difference was statistically significant (P < 0.01). The incidence of dementia decreased with periodontal treatment (OR = 0.96; 95% CI: 0.932–0.992) and increased with dental caries (OR = 1.07; 95% CI: 1.035–1.101).

Conclusions

These results suggest that it is important to delay tooth loss and preserve the stable remaining teeth to help prevent dementia.

Electronic supplementary material

The online version of this article (10.1186/s12903-019-0750-4) contains supplementary material, which is available to authorized users.

The oral health status of residents with different cognitive and dental-related functions in three North Carolina assisted living facilities

INTRODUCTION

The aim of the study was to describe the oral health status of persons with different cognition and dental-related functions (DRFs).

METHODS

The present study was a secondary analysis of data collected for a cross-sectional study of residents in three assisted living facilities in North Carolina. The participants were aged 50 years or older, had normal to severely impaired cognition and spoke English. Upon obtaining informed consent, an oral assessment was completed by a trained geriatric dentist. A research team member who was blind to the oral examination outcomes then used the Minimum Data Set Cognition Scale to assess participants' cognition and the dental activities test to evaluate oral self-care and other DRFs. Descriptive statistics were used to describe the demographic, cognitive, functional and oral health status of the study participants. The impacts of cognitive and functional status on oral health measures were examined using simple linear regression models, negative binomial and zero-inflated negative binomial models.

RESULTS

A total of 91 long-term residents from three long-term care facilities participated in the study. Oral hygiene and gingival health were significantly associated with cognition (P = 0.056 and P = 0.017, respectively) and DRFs (P = 0.013 and P = 0.008, respectively). Residents with poor cognitive and dental-related function also presented with poor oral hygiene and gingival health.

CONCLUSION

The study results suggest that oral hygiene and gingival health were significantly associated with cognition and DRFs.

Tooth loss as a risk factor for dementia: systematic review and meta-analysis of 21 observational studies

BACKGROUND

Tooth loss is suggested to be associated with an increased risk of dementia in many studies. But the relationship between tooth loss and dementia is not yet fully understood. This systematic review and meta-analysis aimed to determine the relative effect of tooth loss on dementia risk.

METHODS

An electronic search of PubMed, Scopus, Embase, and Web of Knowledge was conducted in March 2018 to identify relevant observational studies with the English language restriction. Studies were included if they assessed the relationship between tooth loss and risk of dementia. Study quality was detected by the modified Downs and Black scale. Odds risks (ORs) were pooled using a random-effects model in the crude model.

RESULTS

The literature search initially yielded 1574 articles, and 21 observational studies published between 1994 and 2017 were finally included for the analyses. The crude results with random-effects model showed that patients with multiple tooth loss had higher incidence of dementia (OR 2.62, 95% CI 1.90-3.61, P < 0.001, I² = 90.40%). The association remained noted when only adjusted results were pooled from 18 studies (OR 1.55, 95% CI 1.41-1.70, P = 0.13, I² = 28.00%). Meta-regression analysis showed that study design explained about 16.52% of heterogeneity in the crude model. The overall quality rating scores of studies ranged from 11 to 16.

CONCLUSIONS

Findings from this review evidenced that tooth loss is positively associated with an increased risk of dementia in adults. Future well-designed longitudinal researches examining the direct and indirect relationship between tooth loss and dementia risk are encouraged.

Rehabilitation of lost teeth related to maintenance of cognitive function

OBJECTIVE

As the era of aging comes, cognitive impairment (CI) is increasing. The impact of rehabilitation of lost tooth on CI remains unclear. This study aimed to investigate whether non-rehabilitated lost teeth (NRLT) is associated with CI among Korean elders.

METHODS

A total of 280 elders comprising of 140 cases and 140 age-sex-matched controls were included in this cross-sectional study. CI was assessed using the Mini-Mental Status Examination (MMSE). NRLT was evaluated using panoramic radiograph and oral examination. NRLT was categorized into low (≤4) and high (≥5). Age, sex, education, drinking, smoking, exercise, obesity, hypertension, subclinical atherosclerosis, glucose, cholesterol, depression, and denture-wearing were considered as confounders. Conditional multivariate logistic regression analysis was applied to assess the adjusted association.

RESULTS

NRLT was associated with increased CI after controlling for confounders (odds ratio [OR] = 1.06, 95% confidence interval [95% CFI]: 1.00-1.13). However, lost teeth were not associated with CI. Those with high NRLT (≥5) compared to those with low NRLT (≤4) was more likely to have CI by 2.7 times (OR = 2.74, 95% CFI = 1.28-5.86).

CONCLUSION

Our data showed that NRLT was independently associated with CI. Hence, rehabilitation of the lost teeth could be important for the maintenance of cognitive function.

Environmental Enrichment and Successful Aging

The human brain sustains a slow but progressive decline in function as it ages and these changes are particularly profound in cognitive processing. A potential contributor to this deterioration is the gradual decline in the functioning of multiple sensory systems and the effects they have on areas of the brain that mediate cognitive function. In older adults, diminished capacity is typically observed in the visual, auditory, masticatory, olfactory, and motor systems, and these age-related declines are associated with both a decline in cognitive proficiency, and a loss of neurons in regions of the brain. We will review how the loss of hearing, vision, mastication skills, olfactory impairment, and motoric decline accompany cognitive loss, and how improved functioning of these systems may aid in the restoration of the cognitive abilities in older adults. The human brain appears to require a great deal of stimulation to maintain its cognitive efficacy as people age and environmental enrichment may aid in its maintenance and recovery.

Dental deafferentation and brain damage: A review and a hypothesis

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.

Periodontitis, edentulism and glycemic control in patients with type 2 diabetes: a cross-sectional study

OBJECTIVES

To compare the glycemic control in non-smoking patients with type 2 diabetes according to their periodontal and dental status.

RESEARCH DESIGN AND METHODS

This cross-sectional study investigated patients previously diagnosed with type 2 diabetes and under antidiabetic medication. Clinical data and fasting blood glucose (FBG) levels were collected from medical and dental records. Patients were divided into three groups according to dental and periodontal diagnosis: no or mild periodontitis (NO/MILD, n=96), moderate or severe periodontitis (MOD/SEV, n=74) and edentulous (n=141). FBG levels were compared between groups. Logistic regression was also applied to estimate the OR of presenting hyperglycemia.

RESULTS

Edentulous patients had significantly higher FBG levels of 155.7±70.9 (mean±SD mg/dL) than those in the MOD/SEV (136.6±33.8) and the NO/MILD (123.1±36.7) groups. Differences between the latter two groups were also significant. Edentulous patients had adjusted ORs of 4.53, 4.27 and 3.95 of having FBG≥126, ≥150 and ≥180 mg/dL, respectively, in comparison with NO/MILD group. The MOD/SEV group also presented significant odds of having FBG≥126 mg/dL (OR=2.66) and ≥150 mg/dL (OR=2.45) than the NO/MILD group.

CONCLUSIONS

Patients in the MOD/SEV group had worse glycemic control than the ones in the NO/MILD group. However, edentulous patients presented higher glycemic levels than both dentate groups, and also presented with higher odds of having hyperglycemia.

[Needs for dental prostheses and their use in elderly Brazilians according to the National Oral Health Survey (SBBrazil 2010): prevalence rates and associated factors]

The objectives of this study were to evaluate the use of and need for dental prostheses among elderly Brazilians (65-74 years of age) and to verify associated factors. Data were analyzed from 7,496 elderly participants in the National Oral Health Survey in 2010 (SBBrazil 2010). Use of and need for dental prosthesis were the outcomes. The exposure variables included demographic and socioeconomic characteristics, dental services use, and self-rated oral health. Descriptive, bivariate, and multivariate analyses were performed. Prevalence rates for use of and need for dental prostheses were 78.2% and 68.7%, respectively. The Southeast Region had the highest prevalence of use (71.3%) and the greatest need for dental prostheses (82.9%). Multivariate Poisson regression analyses showed greater use of dental prostheses by women, individuals with 5 to 7 years of schooling, and users of private dental services, and lower use by black individuals and those with self-reported need for dental prostheses. Less need for dental prostheses was seen in women and in users of private services, and greater need in those with self-reported need for dental prostheses. Regional differences were seen in the distribution of use and need for dental prostheses. Still, the findings showed high prevalence rates for both outcomes in all regions of Brazil. Socioeconomic and demographic variables and use of dental services influenced the use of and need for dental prostheses.

Association between mastication and cognitive status: A systematic review

PURPOSE

A substantial number of elderly people suffer from cognitive impairment and dementia, which are considered to have various risk factors, including masticatory dysfunction; however, the association between mastication and cognition is inconclusive. The objectives of this systematic review were to provide an overview of the literature on (1) the association between mastication and cognitive function and (2) the association between mastication and dementia incidence, in elderly people.

MATERIALS AND METHODS

Searches were conducted on five electronic databases (PubMed, EMBASE, CINHL, Cochrane Library, and Pro Quest) and publications were selected that met the following criteria: published between 2005 and 2015, written in English, and assessed associations between mastication and cognitive function, cognitive decline and dementia among population over 40 years old. The included publications were analyzed for study design, main conclusions, and strength of evidence by two reviewers who screened all abstracts and full-text articles, abstracted data and performed quality assessments by using a critical appraisal tool.

RESULTS

A total of 33 articles (22 cross-sectional, and 11 prospective cohort studies) were evaluated. Poorer mastication was associated with lower cognitive function in 15 of the 17 cross-sectional studies and steeper decline in 5 of the 6 prospective studies. Poorer mastication was one of significant risk factors for having dementia or mild memory impairment (MMI) in 4 of 5 cross-sectional studies and for the incidence of dementia or MMI in 4 of 5 prospective studies.

CONCLUSIONS

Most studies point to a positive association between mastication and cognitive function, including dementia among elderly people.

Association of cognitive function with tooth loss and mitochondrial variation in adult subjects: a community-based study in Beijing, China

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.

Association between tooth loss and risk of oesophageal cancer: a dose-response meta-analysis

Many epidemiological studies have found that tooth loss is associated with susceptibility to oesophageal cancer. However, a definitive answer is yet to be discovered, and the findings are inconclusive. We performed a meta-analysis to assess the relationship between tooth loss and oesophageal cancer risk. We searched PubMed and Embase databases to screen eligible studies up to June 2015. Nine observational studies (eight articles) involving 2604 patients and 113,995 participants were included in the meta-analysis. The combined odds ratio for tooth loss and oesophageal cancer was 1.53 (95 % CI 1.02-2.29) for the high versus lowest teeth loss categories. However, inconsistent results were detected in the stratified and sensitivity analysis. In dose-response analysis, the summary odds ratio for each one tooth loss increment was 1.01 (95 % CI 1.00-1.02). The current evidence, based solely on six case-control studies and three cohort studies, suggests that tooth loss is a potential marker of oesophageal cancer. However, no firm conclusion can be drawn at this time that tooth loss may play a causal role in development of oesophageal cancer. Additional large-scale and high-quality prospective studies are required to evaluate the association between tooth loss and risk of oesophageal cancer.

Improved Prefrontal Activity and Chewing Performance as Function of Wearing Denture in Partially Edentulous Elderly Individuals: Functional Near-Infrared Spectroscopy Study

The purpose of this study was to elucidate the effects of wearing a denture on prefrontal activity during chewing performance. We specifically examined that activity in 12 elderly edentulous subjects [63.1±6.1 years old (mean ± SD)] and 12 young healthy controls (22.1±2.3 years old) using functional near-infrared spectroscopy (fNIRS) in order to evaluate the quality of prefrontal functionality during chewing performance under the conditions of wearing a denture and tooth loss, and then compared the findings with those of young healthy controls. fNIRS and electromyography were used simultaneously to detect prefrontal and masticatory muscle activities during chewing, while occlusal force and masticatory score were also examined by use of a food intake questionnaire. A significant increase in prefrontal activity was observed during chewing while wearing a denture, which was accompanied by increased masticatory muscle activity, occlusal force, and masticatory score, as compared with the tooth loss condition. Prefrontal activation during chewing while wearing a denture in the elderly subjects was not much different from that in the young controls. In contrast, tooth loss in the elderly group resulted in marked prefrontal deactivation, accompanied by decreased masticatory muscle activity, occlusal force, and masticatory score, as compared with the young controls. We concluded that intrinsic prefrontal activation during chewing with a denture may prevent prefrontal depression induced by tooth loss in elderly edentulous patients.