Masticatory ability in 80-year-old subjects and its relation to intake of energy,nutrients and food items

Objective: The aim of the present study was to analyse the relationship between masticatory ability (self‐assessed masticatory ability and bite force) and intake of energy, nutrients and food items in a population sample of elderly subjects. Design and Subjects: From a population sample of 80‐year‐old people, 160 individuals (74 men and 86 women) took part in an odontological study. Main Outcome Measures: A dental examination including bite force recording, a questionnaire focusing on self‐assessed masticatory ability, and a dietary interview. Setting: Department of Geriatric Medicine, Göteborg University, Sweden. Results: The dental status among the participants varied much (from edentulous in both jaws ‐ 22% ‐ to more than 20 natural teeth ‐ 30%). The mean maximum bite force was higher in men (165 N) than in women (105 N). Bite force was significantly correlated to the Eichner index and to the number of teeth. One third of the subjects reported no masticatory problem, whereas 18% identified 3 such problems. The intake of energy and nutrients varied much but the means were well above recommended values. The correlations between dental status and bite force on one side and dietary intake on the other side were in general weak and most often statistically non‐significant. Impaired general health and reduced dentition were both associated with more masticatory problems. Conclusion: The examined sample of 80‐year‐old subjects had a great variation in dental status, bite force and self‐assessed masticatory ability, but these factors had only a minor influence on dietary selection and intake, which on average were well above recommended values.     

A study of occlusion in elderly Japanese over 80 years with at least 20 teeth

Objectives: The purpose of this study was to identify the occlusal status of elderly Japanese over 80 years with at least 20 teeth. Materials and methods: The study enrolled 76 elderly Japanese (44 male, 32 female) with a mean age of 82 years and an average of 25.7 remaining teeth. The study consisted of intra‐oral examination, intra‐oral and facial photographs, radiographs and impressions for study casts. Results: No gender difference was observed in age or number of remaining teeth. Anteroposterior occlusal relationship was characterised by maxillary protrusion in 67.6%, acceptable overjet in 31.0%, and anterior crossbite in 1.4%. Vertically, deep bite was noted in 33.8%, acceptable overbite in 64.8%, and open bite in 1.4%. Most of the subjects had either Angle class I (68.4%) or class II (25.7%) canine relationship. Only 3.9% of the subjects had upper anterior crowding. Lower anterior crowding was observed in 23.7%, but tended not to be severe. Conclusion: These results indicate that Japanese who attained the goal of ‘8020’ have a relatively good occlusion.     

Jaw muscles in older overdenture patients

Objective: To determine, using computer tomography (CT), whether the retention of a small number of teeth in the older adult used to support overdentures could affect the cross‐sectional area (CSA) and X‐ray density of two jaw closing muscles. Design: Cross‐sectional study of a group of older patients subdivided into dentate, edentulous and those wearing overdentures supported by two to five teeth. Subjects: The sample consisted of 24 subjects aged 55–68 years. Outcome measures: CSA and X‐ray density of two jaw closing muscles, masseter and medial pterygoid were measured and evaluated using CT. Results: There were no significant differences between left and right jaw muscles, but the CSA of the masseter muscles were significantly larger than the medial pterygoid muscles. The CSA of the masseter and medial pterygoid muscles was significantly smaller in edentulous subjects compared with dentate subjects but no significant difference was observed between subjects wearing overdentures and those with a natural dentition. No significant differences were observed with the X‐ray density between different muscles or dental states. Conclusion: The retention of a small number of teeth in the older adult used to support overdentures appears to sustain the CSA of two jaw closing muscles and therefore could enhance these patients’ masticatory ability compared with those who were edentulous.     

Evolving Teeth Within a Stable Masticatory Apparatus in Orkney Mice

Mice from the Orkney archipelago exhibit an important diversity regarding molar shape. While on some islands mice display a usual dental pattern, teeth from other islands display additional cusplets and unusual phenotypes that may constitute case studies for evaluating the potential functional relevance of dental changes. We developed a multifaceted approach combining 2D and 3D geometric morphometrics, dental topography, dental wear, biomechanics, estimations of masticatory muscles force, and in vivo bite force on wild-derived lab descendants exemplifying the two extreme dental morphologies. The two strains differed in the geometry of the upper and lower tooth rows, and in the topography of the upper row only. Surprisingly, the most unusual tooth morphology appeared as the least complex because tooth simplification overwhelmed the signal provided by the occurrence of additional cusplets. No difference in bite force nor muscle force was evidenced, showing that the important change in dental morphology was accommodated without major changes in the rest of the masticatory apparatus. The evolution of unusual dental phenotypes was possibly fueled by drift and inbreeding in small and isolated populations on remote islands of the archipelago. No functional counter-selection impeded this diversification, since the unusual dental phenotypes did not disrupt occlusion and mastication.     

Oral status and its association with obesity in Southern Brazilian older people

Background and objective: The loss of a functional dentition imposes eating difficulties and food avoidance, which may be detrimental in terms of nutritional status and health. The objective of this study was to investigate whether tooth loss and edentulism that were not rehabilitated with dental prostheses were associated with obesity among elderly in Southern Brazil. Materials and methods: A random sample of 872 independently living elderly was evaluated by means of a cross‐sectional study. Socio‐demographic, medical history and behaviour data were assessed using a standardised questionnaire. Two trained dentists assessed the number of teeth and use of prostheses in accordance with the WHO criteria. Height and weight were assessed and used to generate body mass index (BMI = weight (kilos)/height (cm)²) data. Participants were categorised into non‐obese (BMI ≤ 30) or obese (BMI > 30). Multivariate logistic regression was used to model the relationship between number of teeth and use of dental prostheses with obesity adjusting for confounders. Results: Multivariate logistic regression revealed that edentulous persons wearing only upper dentures (OR = 2.34, 95% CI 1.18–4.27) and dentate participants with one to eight teeth wearing 0‐to‐1 prosthesis (OR = 2.96, 95% CI 1.68–5.19) were more likely to be obese. Conclusion: The results show that a poorer oral status, represented by having fewer teeth that were not replaced by dental prostheses, was associated with obesity in Southern Brazil older people, suggesting a close relationship between poor oral status and systemic conditions that may have important clinical implications.     

A study of some masticatory functions in 90-year old subjects

A group of 35 90-year old subjects, randomly selected from the gerontologic population study in Göteborg (H-70), were examined with respect to function and dysfunction of the masticatory system. The methods included a questionnaire, clinical examination and recording of bite force endurance and maximal bite force, measured in the central incisor region. Forty percent were edentulous, 29% were partially edentulous and wore a removable denture, while the others were dentate without removable prostheses. Signs and symptoms of temporomandibular disorders were mostly mild and infrequent, except TMJ crepitation which was recorded in 69% of the subjects. Maximal bite force was in general low (mean 94 N) but showed a great individual variation (range 10 to 410 N). Bite force endurance was also very variable (mean 72 s, range 10 to 205 s). None of the 35 subjects reported poor masticatory ability, but 2 said they could not chew all kinds of food. In spite of a reduced bite force this group of 90-year olds considered their masticatory ability as good and most of them had no severe signs and symptoms of temporomandibular disorders.     

Evaluation of a self-assessed screening test for masticatory ability of Taiwanese older adults

doi: 10.1111/j.1741‐2358.2012.00632.x Evaluation of a self‐assessed screening test for masticatory ability of Taiwanese older adults Objectives: The aim of this study was to evaluate a screening test based on a food intake questionnaire to discriminate the masticatory ability of Taiwanese older adults with 20 and more natural teeth and at least 8 functional tooth units (FTUs) from the masticatory ability of those with fewer than 20 natural teeth and 8 FTUs. Materials and Methods: The subjects were 2244 patients (mean age, 60.4±10.0 years) recruited from 23 counties and cities in Taiwan. Information about their demographic data, dentition, and masticatory ability was collected. Masticatory ability was measured for 23 food groups comprising 35 common Taiwanese foods, and receiver operation characteristic curve analysis was performed. Results: The results showed that the final questionnaire included 14 food groups and a subject choosing ’difficult to eat‘ responses for 4 and more of these food groups had the same masticatory ability as individuals with fewer than 20 natural teeth and 8 FTUs. Conclusion: In conclusion, foods that are the most difficult to eat are not necessarily good discriminatory indicators. Hence, the 14‐food group questionnaire can be considered the best screening test for masticatory ability of Taiwanese older adults in terms of the presence of 20 and more natural teeth and at least 8 FTUs.     

The influence of feeding on the evolution of sensory signals: a comparative test of an evolutionary trade‐off between masticatory and sensory functions of skulls in southern African Horseshoe bats (Rhinolophidae)

The skulls of animals have to perform many functions. Optimization for one function may mean another function is less optimized, resulting in evolutionary trade‐offs. Here, we investigate whether a trade‐off exists between the masticatory and sensory functions of animal skulls using echolocating bats as model species. Several species of rhinolophid bats deviate from the allometric relationship between body size and echolocation frequency. Such deviation may be the result of selection for increased bite force, resulting in a decrease in snout length which could in turn lead to higher echolocation frequencies. If so, there should be a positive relationship between bite force and echolocation frequency. We investigated this relationship in several species of southern African rhinolophids using phylogenetically informed analyses of the allometry of their bite force and echolocation frequency and of the three‐dimensional shape of their skulls. As predicted, echolocation frequency was positively correlated with bite force, suggesting that its evolution is influenced by a trade‐off between the masticatory and sensory functions of the skull. In support of this, variation in skull shape was explained by both echolocation frequency (80%) and bite force (20%). Furthermore, it appears that selection has acted on the nasal capsules, which have a frequency‐specific impedance matching function during vocalization. There was a negative correlation between echolocation frequency and capsule volume across species. Optimization of the masticatory function of the skull may have been achieved through changes in the shape of the mandible and associated musculature, elements not considered in this study.     

Eight-year mortality associated with dental occlusion and denture use in community-dwelling elderly persons

Objective: To evaluate the influence of dental occlusion, with or without the use of dentures, on mortality in community‐dwelling elderly persons. Subjects: A total of 1030 randomly selected healthy independent elderly aged 65 and over were surveyed in 1995. For the study reported here, subjects were classified into three groups according to the presence or absence of maxillo‐mandibular tooth contacts. Subjects with no maxillo‐mandibular tooth contacts were further subdivided into those with and without dentures. Methods: Data on mortality were obtained from Kure City Council in September 2003. Cox regression models were used in analysing the risk for death with gender and age as covariates. Results: Individuals whose teeth had contact in at least the bilateral premolar regions at baseline had 0.78 times (95% CI: 0.60–0.99) smaller risk for death during the succeeding 8 years than those who had no occlusion. Among those who had no occlusion with their own teeth, the risk for mortality among denture non‐users was 1.52 times (95% CI: 1.25–1.83) higher than the risk for denture users. Conclusion: These results may support the view that, in the elderly, poor dental occlusion is associated with an increased risk for mortality and that, in the edentulous, the use of dentures is associated with a decreased risk for mortality.     

The masticatory handicap of wearing removable dentures in elderly men

Objective: This study aimed at describing the masticatory handicap of wearing removable dentures measured by some masticatory tests and the intake of hard and soft foods. Materials and methods: The subjects were participants in a comprehensive health examination of 67–68‐year‐old men living in Malmö, Sweden. Four hundred eighty‐three men took part in a clinical oral examination which recorded the number of teeth and removable dentures. One hundred and one had complete dentures in both jaws and 131 had removable partial dentures in different combinations. Masticatory tests used almonds to record the number of stokes to the first swallow, and two‐coloured chewing gums for recording bolus kneading and shaping. A nutritionist paid a home visit to assess dietary habits including the consumption of hard and soft foods. The data could be split into groups of different tooth and denture situations which were large enough to enable statistical analysis to be carried out. The results of a regression analysis of the group with different numbers of natural teeth (NT) and no removable dentures could be used as a reference for correlation with the masticatory capacity of removable denture wearers. Results: Number of strokes to the first swallow revealed no masticatory limitations of wearing removable dentures, while chewing gum colour‐mixing and shaping revealed more differentiated impairments equivalent to the function of five to 16 teeth in a remaining natural dentition. Hard food intake for the removable denture groups was comparable to 17–19 NT. Soft food intake was not influenced by denture wearing. In a ranking of oral conditions, those with more than 24 NT had the highest test values for all tests, and those with complete sets of dentures the lowest except for the number of strokes to the first swallow of an almond. Conclusion: Removable denture wearing can be regarded as a handicap when measured with objective masticatory tests using chewing gum and the intake of hard foods. The number of chewing strokes to the first swallow of an almond and the intake of soft foods is not affected by the wearing of removable dentures.     

The number of missing teeth in people of the Edo period in Japan in the 17th to 19th centuries

doi: 10.1111/j.1741‐2358.2011.00511.x The number of missing teeth in people of the Edo period in Japan in the 17th to 19th centuries Objective: The aims of this study were to examine the number of missing teeth in the people of the Edo period (or number of remaining teeth) and to contribute to the 8020 movement proposed in Japan to help people retain 20 or more of their own teeth until the age of 80. Background: The study of dentition in ancient skeletal remains of our ancestors from multiple perspectives can yield information that can contribute to the study of physical anthropology and the leading edge of modern dental research. Materials and methods: The materials were 82 excavated individuals (52 males and 30 females) from 1603 to 1868 whose maxillas and mandibles were both examinable. The age and sex were estimated by anthropological methods, and the individuals were divided into five groups. The status of missing teeth was compared between groups, and a chi‐square test was used to test significant differences between groups. The rates of tooth loss were examined in the maxillas and mandibles. Results: In the people of the Edo period, many teeth remained in good condition until early to late middle age. There were more remaining teeth in these individuals than in modern‐day individuals. However, the Edo people clearly showed increased tooth loss with age. There were no differences in tooth loss by sex. The tooth type with a high rate of tooth loss was posterior teeth, but incisor loss also occurred with ageing. Mandibular canines were most likely to be remaining. Conclusion: The Edo people had more remaining teeth than modern‐day society. This finding was unexpected. The notion that “people of long past ages lost more teeth more quickly” does not seem to apply to people in the Edo period in Japan.     

Masticatory Muscle Anatomy and Feeding Efficiency of the American Beaver, <Emphasis Type="Italic">Castor canadensis</Emphasis> (Rodentia,Castoridae)

Beavers are well-known for their ability to fell large trees through gnawing. Yet, despite this impressive behavior, little information exists on their masticatory musculature or the biomechanics of their jaw movements. It was hypothesized that beavers would have a highly efficient arrangement of the masticatory apparatus, and that gnawing efficiency would be maintained at large gape. The head of an American beaver, Castor canadensis, was dissected to reveal the masticatory musculature. Muscle origins and insertions were noted, the muscles were weighed and fiber lengths measured. Physiological cross-sectional areas were determined, and along with the muscle vectors, were used to calculate the length of the muscle moment arms, the maximum incisor bite force, and the proportion of the bite force projected along the long axis of the lower incisor, at occlusion and 30° gape. Compared to other sciuromorph rodents, the American beaver was found to have large superficial masseter and temporalis muscles, but a relatively smaller anterior deep masseter. The incisor bite force calculated for the beaver (550–740 N) was much higher than would be predicted from body mass or incisor dimensions. This is not a result of the mechanical advantage of the muscles, which is lower than most other sciuromorphs, but is likely related to the very high percentage (>96 %) of bite force directed along the lower incisor long axis. The morphology of the skull, mandible and jaw-closing muscles enable the beaver to produce a very effective and efficient bite, which has permitted beavers to become highly successful ecosystem engineers.     

Tooth loss, the wearing of dentures and associated factors in Sri Lankan older individuals

Objective: To determine tooth loss, wearing of dentures and associated factors in older individuals from Sri Lanka. Design: A cross‐sectional survey where the data were collected by means of an oral examination and an interviewer administered questionnaire. Setting: Negambo within the Gampaha district of Sri Lanka. Subjects: A total of 630 subjects who were aged 60 years and above. Results: Only 11 subjects had all 32 teeth and 17% were edentulous. Age, gender and level of income were significantly associated with the number of missing teeth. Of those with missing teeth, 22% wore dentures. Only 16% of the non‐denture wearers perceived a need for dentures. Among the non‐denture wearers who perceived a need for dentures, a majority had cited ‘cost’ as the main barrier for obtaining dentures. Logistic regression analysis revealed that age, gender, levels of income and education and missing teeth were significant predictors of wearing of dentures. Conclusions: Knowledge of factors that influence tooth loss and wearing of dentures may have implications for oral health care planners in the provision and delivery of oral health services to the older individuals.     

Attitudes to the importance of retaining natural teeth in an adult Swedish population

Objectives . To evaluate the attitudes to retaining natural teeth in an adult Swedish population, and to correlate the attitude to retaining natural teeth with some presumed influencing background factors. Design : Cross-sectional study using a newly developed questionnaire. Subjects : From the national census register of four municipalities in the southern part of the province of Halland, Sweden, with a total population of 126,878 adult (≥20 years) inhabitants, 4,200 persons were selected at random. The sample was randomised by age and sex, and 300 men and 300 women from the age groups 20, 30, 40, 50, 60, 70, and 80 years were included. Intervention and main outcome measures : The questionnaire aimed to evaluate the number of remaining natural teeth, the dental care habits, the self-estimated quality of natural teeth, and the attitude t o retaining natural teeth In the studied population, and also to evaluate the possible correlation between those factors, in particular, the attitude to retaining natural teeth versus the other factors. Results : It was found that the attitude to the importance of retaining natural teeth was strongly correlated with the number of remaining natural teeth, the dental care habits, and the self-estimated quality of natural teeth. Also sex had an influence on this attitude but not age. Conclusions : The attitude to the importance of retaining natural teeth in an adult Swedish population is correlated with the number of remaining natural teeth, the dental care habits, the self-estimated quality of natural teeth, and sex, but not with age.     

Effect of bone mineral density on masticatory performance and efficiency

doi: 10.1111/j.1741‐2358.2010.00414.x Effect of bone mineral density on masticatory performance and efficiency Objective: To evaluate the effect of bone mineral density (BMD) on masticatory performance and efficiency in dentate subjects. Background data: Osteoporosis is the most common disorder of the bone. It causes reduction in BMD of the all the skeletal tissue including jaw bones. It also promotes bone loss in jaw bones. In osteoporosis, a reduction of maximal bite force and greater electromyography activity of masticatory muscles is documented. This may lead to the development of masticatory dysfunction which can be assessed by a chewing test in the form of change in masticatory performance and efficiency. Materials and methods: Sixty subjects with equal numbers of men and women were selected for the study, in which BMD screening (T‐score) was carried out to identify the normal, osteopenic and osteoporotic subjects. Their masticatory performance and efficiency was evaluated by a chewing test (fractional sieving method). Results: A high ‘T’ score was associated with low masticatory efficiency and a low ‘T’ score with high masticatory efficiency. Masticatory performance and efficiency was significantly higher among males as compared to females with similar range of BMD. Conclusion: In both genders, high BMD groups (low ‘T’ score) had a significantly high percentage of masticatory efficiency compared to the low BMD (high ‘T’ score) group.     

Implant overdentures for edentulous elders: study of patient preference

Background: Studies show that elders wearing implant overdentures have improved nutrition and quality of life. However, upfront costs of this therapy are high, and the income of elderly edentulous populations is low. Objectives: This study was designed (i) to measure the preferences of edentulous patients for mandibular two‐implant overdentures using Willingness‐To‐Pay (WTP) and Willingness‐To‐Accept (WTA), (ii) to assess the effect of long‐term financing on WTP and (iii) to assess the desired role of health care plans in financing dental prostheses. Methods: Edentulous elders (68–79 years; n = 36) wearing maxillary dentures and either a mandibular conventional denture (CD, n = 13) or a two‐implant overdenture with ball attachments (IOD, n = 23) participated in this study. All had received their prostheses 2 years previously, as part of a randomised clinical trial. A three‐part questionnaire was completed during a 20‐min interview with a trained researcher. Results: Forty‐six per cent (6/13) of the CD wearers and 70% (16/23) of the IOD wearers were willing to pay three times more than the current cost of conventional dentures for implant prostheses. These percentages were increased to 77% (CD) and 96% (IOD) if participants could pay for implant overdentures in monthly instalments. Eighty‐six per cent (31/36) of all participants in both groups (21/23 IOD; 10/13 CD) thought that the government should cover at least some of the cost of implant overdentures. Conclusions: This study shows that, the majority of elderly edentate individuals who have not experienced mandibular two‐implant overdenture therapy are willing to pay the cost, particularly when payment can be made in monthly instalments.     

Associations between self-assessed masticatory ability and some general health factors in a Swedish population

Objectives : The aims of this study were 1) to describe changes in self-assessed masticatory ability over a 14 year period (1975–89); and 2) to describe associations between self-assessed masticatory ability and age, dental state and some other background factors in a sample of the Swedish population in 1988/89. Design: The Swedish National Central Bureau of Statistics investigates annually the living conditions of the Swedish population by means of interviews by trained persons. The data were analysed by means of stepwise logistic regression and calculation of adjusted relative risks. Subjects: In the investigation in 1988/89, 12901 people above 16 years of age participated and the response rate was 80%. Results: In comparison between the investigations, the prevalence of reported impairment was lower in 1988/89 than in 1975 and 1980/81. Prevalence of reported impairment of chewing ability increased with ageing from 2% in young adults (16–34 years old) to 44% in older elderly (>85 years old). In most age groups, edentulous people reported the highest prevalence, and dentate people the lowest. Relative risks for impaired masticatory ability, independent of age, gender and dental state, were higher for people in rural areas, with low income and living single, as well as for those with skeletal, gastrointestinal, psychiatric and tumour diseases. In the elderly, results from the logistic regression showed that some disability and psychosocial factors were also associated with masticatory ability. Conclusions : The results indicated that there was a group of elderly people who reported several functional and health problems including impaired masticatory ability.     

Influence of dental treatment on physical performance in community-dwelling elderly persons

doi: 10.1111/j.1741‐2358.2011.00563.x
Influence of dental treatment on physical performance in community‐dwelling elderly persons Objective: The aim of the study was to investigate the influence of dental treatment on physical performance (muscle strength and balance function) among the elderly. Background: Oral conditions have been associated with physical performance. We hypothesised that improved oral conditions by dental treatment would lead to improved physical performance. Methods: A total of 154 persons aged 65 years or over were judged to be in need of dental treatment as a result of dental examination; of these, 121 persons underwent dental treatment. After 1 year, differences in each parameter of physical performance before and after the intervention were evaluated using the Wilcoxon signed rank sum test. The Spearman rank correlation coefficient was calculated to examine correlations between changes in self‐assessed masticatory ability (masticatory ability) and each parameter of physical performance, and multivariate logistic regression analysis was performed using changes in each parameter of physical performance as the dependent variable and changes in masticatory ability as the principal independent variable. Results: Improved physical performance was not observed for the total study population with dental treatment; however, in subjects with improved masticatory ability, one‐leg standing times with eyes open increased significantly. A significant correlation was established between changes in masticatory ability and each parameter of physical performance. These relationships were not found in those without dental treatment. A significant relationship was also established for one‐leg standing time after adjusting for age, gender, dentition status and needs of dental treatments. Conclusion: Chewing ability may be a positive contributing factor to balance function among the elderly.     

Oral hygiene of elderly people in long-term care institutions--a cross-sectional study

Objective: The aim of this cross‐sectional study was to assess the level of oral hygiene in elderly people living in long‐term care institutions and to investigate the relationship between institutional and individual characteristics, and the observed oral cleanliness. Materials and methods: Clinical outcome variables, denture plaque and dental plaque were gathered from 359 older people (14%) living in 19 nursing homes. Additional data were collected by a questionnaire filled out by all health care workers employed in the nursing homes. Results: Only 128 (36%) residents had teeth present in one or both dental arches. About half of the residents (47%) wore complete dentures. The mean dental plaque score was 2.17 (maximum possible score = 3) and the mean denture plaque score was 2.13 (maximum possible score = 4). Significantly more plaque was observed on the mucosal surface of the denture with a mean plaque score of 2.33 vs. 1.93 on the buccal surface (p < 0.001). In the multiple analyses only the degree of dependency on an individual level was found to be significantly correlated with the outcome dental plaque (odds ratio: 3.09) and only the management of the institution with denture plaque (odds ratio: 0.43). Conclusion: Oral hygiene was poor, both for dentures and remaining teeth in residents in long‐term care institutions and only the degree of dependency of the residents and the management of the institutions was associated with the presence of dental plaque and denture plaque respectively.