Association between functional dental state and dietary intake of Chinese vegetarian old age home residents

Objective: To examine the association between dental functional status and dietary intakes of Chinese vegetarian old age home residents. Subjects and methods: A cross‐sectional survey was performed in a group of 76 older vegetarian Chinese women living in an old age home. Oral examination was performed by a dental surgeon. Sixty‐eight of them had a 24‐hour food record by direct observation, analysed by a Chinese food composition table. Nutritional status was measured by Body Mass Index (BMI), and the functional status by modified Barthel Index (BI). Results: Forty‐two subjects (55.3%) were edentulous; 59 subjects (77.6%) had chewing difficulties; 35 subjects (46%) had poor dental functional status defined by having five or less functional teeth unit (FTU). When compared with those older people with better dental functional status, the poor dental functional status group was more likely to have chewing difficulties, tolerate soft diet only, and be functionally dependent (BI < 15/20). Poor dental functional status was associated with lower mean daily fibre intake, but not with intakes of macronutrients and micronutrients, after adjustment by BI categories. Conclusion: Poor dental functional status is associated with impaired chewing and lower fibre intake in Chinese vegetarian old age home residents, but it is not associated with reduced intakes of macronutrients or micronutrients.     

Relationship between chewing ability and high-level functional capacity in an 80-year-old population in Japan

Objectives: To evaluate the association between high‐level functional capacity and chewing in a middle‐old community‐based population. Background: Although basic and instrumental activities of daily living are known to be associated with chewing ability in the elderly, an association between higher levels of competence and chewing ability has not been evaluated in the elderly. Materials and methods: The association between chewing ability using a number of different foods and high‐level functional capacity by the Tokyo Metropolitan Institute of Gerontology was evaluated in 694, 80‐year‐old people residing in Fukuoka Prefecture, Japan. Results: A significant correlation was found, using multiple regression or logistic regression analyses adjusted for various confounding factors, between the number of total chewable foods, hard foods or moderately hard foods, and total functional capacity, instrumental activity, intellectual activity or social role ability. In contrast, the number of slightly hard foods, easily chewable foods and remaining teeth were only partly related to total functional capacity and intellectual activity. Conclusion: High‐level functional capacity including intellectual activity and social role in middle‐old elderly was associated with the ability to chew hard foods than to chew easily chewable foods. Maintenance of chewing ability in elderly might result in better intellectual activity and social role.     

Socio-medical condition and oral functional status in an older institutionalised population

Objectives: To investigate the association between the general medical condition, the socio-economic status, and some factors related to the functional status of the stomatognathic system. Design: A survey in an elderly population. Subjects: 257 older adults, with a mean age of 83.7 years. Setting: Residential homes for the elderly. Intervention: Examination of the medical records on the overall health and the drugs consumed, a structured interview on the socio-economic status, the complaints for xerostomia, the subjective chewing difficulties, and a clinical evaluation of the number of natural teeth and the number of posterior occluding pairs of teeth contacts (premolars and molars). Results: Multiple pathology and polypharmacy were recorded. 25% of the residents had no occluding posterior tooth contact (natural or prosthetic) and 62% were edentulous. 43% of the residents reported complaints for xerostomia, and 46% for chewing difficulties when eating specific food types. Xerostomic feelings and chewing problems were not related to age. Chewing difficulties were not related to the number of natural teeth, but to the number of posterior occluding teeth contacts, natural or prosthetic (less than two). From all medical conditions examined, only the psychiatric disorders were significantly related to dental status (p<0.05). Moreover, the number of remaining natural teeth was related to socio-economic status, while the number of posterior occluding teeth contacts was also inversely related to the duration of institutionalisation (p<0.05). Conclusions: Psychiatric disorders, low socio-economic status and increased duration of institutionalisation were most closely related to poor dental status. The presence of more than two posterior occluding teeth contacts, natural or prosthetic, benefit the very old patient in terms of reduced subjective chewing difficulty. A formal oral care delivery system for the institutionalised elderly, and particularly for those suffering from psychiatric disorders, is imperative.     

Effect of dental status on changes in mastication in patients with obesity following bariatric surgery

Background

Patients scheduled for bariatric surgery (BS) are encouraged to chew slowly in order to optimise the digestion process. The influence of dental status on patients'' ability to comply with advice on chewing behaviour is poorly documented. This study aims to compare modifications of chewing function before and after BS in three groups of obese patients differing in dental status.

Method and Findings

A cohort of 46 obese women provided three groups: FD group: fully dentate (7–10 functional dental units [FU]); PD group: partially dentate (4–6 FU) without partial dentures; DW group: partial and complete denture wearers. Chewing time (CT), number of chewing cycles (CC), and chewing frequency (CF) were measured before and after surgery during mastication of standardised samples of raw carrot, peanuts, banana, apple and jelly. The median particle-size distribution (D50) of the pre-swallowed bolus was also evaluated for peanut and carrot. Before surgery, the PD and DW groups exhibited greater mean CCs and CTs than the FD group (SNK p<0.05) and produced a bolus with higher granulometry (SNK, p<0.05) than the FD group. After surgery, CT and CC increased for all groups and for all foods, but not statistically significant for jelly. The resulting changes in bolus granulometry observed depended on both food and dental status. The granulometry of carrot bolus remained as fine or as coarse in FD and DW groups respectively as it was before surgery while it was significantly decreased in the PD group (Student''s test, p<0.001).

Conclusions

After bariatric surgery, all the obese patients, regardless of dental status modified their chewing kinematics. The effects of this chewing behaviour on bolus granulometry depended on dental status and type of food. Further studies are needed to understand better the impact of dental status on feeding behaviour and nutrition in patients with obesity.     

Electromyographic evaluation of masseter and anterior temporalis muscles in rest position of edentulous patients with temporomandibular disorders, before and after using complete dentures with sliding plates

Objectives: This study was performed with the purpose of investigating electromyographic (EMG) activity of the anterior temporalis and masseter muscles in edentulous individuals with temporomandibular disorder (TMD), before and after using sliding plates on complete dentures in the mandibular rest position. Background: Edentulous patients may present TMD, which is characterised by pain in temporomandibular joints, masticatory and neck muscles, uncoordinated and limited mandible movements, joint sounds and an altered occlusal relationship. It is imperative to offer treatment in order to re‐establish stomatognathic system structures before submitting the individual to any definitive restorative treatment. Materials and methods: The patients were edentulous for at least 10 years. EMG recordings were made before the insertion of the dentures (0 months) and also after using the sliding plates at the fourth month, 9th month and 12th month, using computerised electromyography K6‐I/ EMG Light Channel Surface. EMG evaluations of the muscles were performed under the following clinical conditions: rest position with dentures (R1), rest position without dentures (R2), rest position with dentures post‐activity (chewing) (R3), rest position without dentures post‐activity (chewing) (R4). Results: All patients obtained remission of muscular fatigue and reduced pain in stomatognathic system structures. Temporalis muscle showed significant increase in EMG activity compared with initial values (p < 0.01). Masseter muscles showed significantly lower mean values (p < 0.01) compared with initial values. Conclusion: The sliding plates allowed the process of neuromuscular deprogramming, contributing to muscular balance of the masticatory system, and are therefore indicated to be used before the fabrication of definitive complete dentures in patients with TMD.     

Effects of oral functional training for nutritional improvement in Japanese older people requiring long-term care

Objectives: The aim of this study was to evaluate the effect of oral functional training and nutrient supplements to improve the nutrition of malnourished elderly people in a nursing home. Background: Malnutrition is a frequent problem in the elderly requiring long‐tem care; however, it is not clear whether oral functional training can be effective to improve nutrition. Subjects and methods: Fourteen subjects of 82 residents (mean age 85.7 ± 6.2 years) in a nursing home, who had a serum albumin level of ≤3.8 g/dl and understood the purpose of this study, were randomly divided into two groups of seven: one group served as the supplement group (mean age 87.0 ± 4.9 years) to which a high‐calorie and high‐protein diet was provided, and the other as the oral training plus supplement group (mean age 84.6 ± 10.1 years) to which oral functional training was given by a dental hygienist once a week as well as the above diet. Nutritional status was evaluated using serum biochemical values as indices at 4 months after the start of the intervention. Results: In the supplement group, serum albumin was 3.44 ± 0.36 g/dl at the start of the study (before intervention) and 3.24 ± 0.45 g/dl at 4 months after intervention. In the oral training plus supplement group, it was 3.56 ± 0.22 g/dl before intervention and significantly increased to 3.70 ± 0.33 g/dl after intervention (p < 0.05: Wilcoxon signed‐rank test). Conclusion: Nutritional supplements alone were not adequate, but with oral functional training to maintain and improve feeding function, nutritional improvement in the elderly could be observed.     

Relating neuromuscular control to functional anatomy of limb muscles in extant archosaurs

Electromyography (EMG) is used to understand muscle activity patterns in animals. Understanding how much variation exists in muscle activity patterns in homologous muscles across animal clades during similar behaviours is important for evaluating the evolution of muscle functions and neuromuscular control. We compared muscle activity across a range of archosaurian species and appendicular muscles, including how these EMG patterns varied across ontogeny and phylogeny, to reconstruct the evolutionary history of archosaurian muscle activation during locomotion. EMG electrodes were implanted into the muscles of turkeys, pheasants, quail, guineafowl, emus (three age classes), tinamous and juvenile Nile crocodiles across 13 different appendicular muscles. Subjects walked and ran at a range of speeds both overground and on treadmills during EMG recordings. Anatomically similar muscles such as the lateral gastrocnemius exhibited similar EMG patterns at similar relative speeds across all birds. In the crocodiles, the EMG signals closely matched previously published data for alligators. The timing of lateral gastrocnemius activation was relatively later within a stride cycle for crocodiles compared to birds. This difference may relate to the coordinated knee extension and ankle plantarflexion timing across the swing-stance transition in Crocodylia, unlike in birds where there is knee flexion and ankle dorsiflexion across swing-stance. No significant effects were found across the species for ontogeny, or between treadmill and overground locomotion. Our findings strengthen the inference that some muscle EMG patterns remained conservative throughout Archosauria: for example, digital flexors retained similar stance phase activity and M. pectoralis remained an ‘anti-gravity’ muscle. However, some avian hindlimb muscles evolved divergent activations in tandem with functional changes such as bipedalism and more crouched postures, especially M. iliotrochantericus caudalis switching from swing to stance phase activity and M. iliofibularis adding a novel stance phase burst of activity.     

General health, dental status and perceived dental treatment needs of an elderly population in Istanbul

doi: 10.1111/j.1741‐2358.2010.00363.x
General health, dental status and perceived dental treatment needs of an elderly population in Istanbul Background: Comprehensive data on the oral health status and dental treatment needs of the elderly population in Turkey are deficient. Objectives: This pilot study determined the general and dental health status, perceived medical and dental treatment needs of an elderly population dwelling in residential homes in Istanbul. Method: Subjects at three different residential homes, namely one belonging to the state and two supported by foundations in Istanbul (N=121, female: 63 and male: 58) were involved in this study. A detailed questionnaire was prepared and dental examinations were conducted. Information was collected related to age, education levels, financial status, current physical functional status, general health, mental health, previous dental history, current dental status, oral hygiene practices and denture hygiene of these elderly people. The prevalence of edentulism, the presence and type of dental prostheses, dental and denture status and denture cleanliness were further evaluated. Results: The three most prevalent reported general health problems were associated with genito‐urinary problems (24%) followed by cardiovascular (18%) and respiratory problems (14%) varying significantly between genders, with males suffering more from cardiovascular problems than females (p < 0.05). Females showed significantly higher gastrointestinal and orthopaedic problems than males (p < 0.05). Females were more frequently edentulous than males but denture hygiene was significantly better in females than in males (p < 0.05). Brushing frequency did not significantly increase denture hygiene (p = 0.6). More than one‐third of the subjects had not been to the dentist within the previous 5–10 years, mainly due to lack of demand, followed by the cost of the dental care and fear. More than two‐thirds of denture‐wearing subjects wore their dentures only during eating. Conclusions: There was significant perceived dental treatment and care need for the sample population of elderly studied.     

Utilization of dental health services by community-dwelling older adults in Japan who attended a weekly educational programme

Objectives: The purpose of this study was to describe dental health services utilization and identify factors which influenced a group of independently living elderly persons in an urban area of Japan. Subjects: The study sample consisted of 2,990 participants, 83% of the total sample of the Senior Citizen's College, who were 60 years and over. Measurements: Their dental utilization and satisfaction with dental treatment were measured by a questionnaire from 1993 to 1998 Results: The mean age of the subjects was 66.5 years and 52% were male. Sixty percent of the subjects had visited a dentist within the previous year, and 33% of them had received a regular oral health check‐up. The majority of the subjects (63%) were satisfied with their dental treatment. A multiple stepwise logistic regression analysis showed that dental services utilization had a significant positive association with presence of teeth (p<0.001), being male (p<0.01) and satisfaction with financial status (p<0.05). A regular oral health check‐ups had a significant association with presence of teeth (p<0.001), satisfaction with financial status (p<0.05) and aging (p=0.001). Conclusions: Dental health services utilization was related to the presence of teeth and financial status, rather than age or medical conditions, among independently living elderly persons in an urban area of Japan.     

Electromyographic responses to prescribed mastication.

The aim was to understand between-volunteer differences in Electromyography (EMG) behaviour during chewing. EMG was used to record the electrical activity of the temporal and masseter muscles of volunteers, who carried out mastication movements by operating calibrated springs held between their incisors. The volunteers coordinated their jaw movements with the signal produced by a metronome, at four rates: 30, 60, 90 and 120 beats per minute (bpm). Raw data were analyzed to examine the distributions of the intervals between chews. For the highest prescribed chew rates, the volunteers' distributions were very similar. The distributions varied most for the 30 bpm data, suggesting that volunteers differed in their ability to carry out and maintain this prescribed chewing pattern. The data were Fourier transformed to give power spectra in the frequency domain. The low frequency (<10 Hz) region contained spectral features related to the prescribed chew rate. Principal component analysis of the power spectra revealed that readings from each volunteer clustered together, and the clusters could be largely separated. Such grouping was found irrespective of whether data from each chew rate were analyzed separately or simultaneously. This indicated that within-volunteer variance, arising from the different chew rates as well as between-session variance, is lower than between-volunteer variance; even when individuals are asked to make jaw movements in the same prescribed manner, they can nevertheless be uniquely distinguished by their muscle activity as recorded by EMG.     

EMG study on the effect of ageing on the human masseteric jaw-jerk reflex

The effect of age on the masseteric jaw-jerk reflex was investigated in 22 young (11 males and 11 females with mean age 23.2 years) and 22 older dentate subjects (11 males and 11 females with mean age 61.3 years). Electromyographic (EMG) recordings were obtained, after chin taps, from the relaxed masseter muscle of the preferred chewing side, by use of a computerised recording and analysis system. With increasing age the occurrence of the reflex was reduced, the latency was increased, while the amplitude was decreased. Those findings are probably related to the general age related changes in the muscular tissue, the sense organs, the peripheral nerves and especially the central nervous system, Increased biological variance was also observed in the older subjects, as in most aspects of performance in the latent years. Furthermore, the effects of ageing were generally similar in men and women. The age-related decrement in the monosynaptic reflex response is indicative of a generalised decline in the motor performance of the stomatognathic system and the decreased ability of the older dental patient to easily adapt to any dramatic changes in the sensory input.     

Long-term electromyographic activity in upper trapezius and low back muscles of women with moderate physical activity.

The habitual activity patterns of trapezius and postural back muscles (multifidus, iliocostalis, longissimus) of 23 female subjects with moderate physical activity were studied. Bilateral surface electromyographic (sEMG) recordings from start of work until bedtime were analyzed. The activity level was calibrated as percentage of root mean square-detected muscle activity at maximal voluntary contraction (EMG(max)). Sixty-six previous trapezius recordings of women with moderate physical activity were included in some analyses to pursue the full range of variation in trapezius activity. Twenty-six of these were recorded twice, separated by 16-28 mo. Median activity level and duration of periods with sEMG activity of <0.5% EMG(max) ("rest time"; only trapezius) and exceeding 2 ("burst time"), 10, 30, and 50% EMG(max) was determined. The trapezius median activity level ranged from 0.6 to 8.8% EMG(max), burst time from 9 to 84%, and rest time from 2 to 84%. The activity patterns of the back muscles showed similar large interindividual variation. Repeated trapezius recordings of the same subject showed high consistency; intraclass correlation coefficients ranged from 0.62 to 0.79 for different sEMG variables. Periods with high sEMG amplitude were of short duration; 7% of the trapezius recordings did not present time intervals (0.2-s duration) above 50% EMG(max). The activity patterns of the postural muscles, despite large interindividual variability, were distinctly different from activity patterns of upper and lower limb muscles reported by others (e.g., mean burst time 40-50 vs. 10-20%). We conclude that postural trunk muscles show idiosyncratic activity patterns with large interindividual variation. High-threshold motor units are activated to a very minor extent.     

Functional tooth units and nutritional status of older people in care homes in Indonesia

Gerodontology 2012; doi: 10.1111/j.1741‐2358.2012.00673.x Functional tooth units and nutritional status of older people in care homes in Indonesia Objectives: To investigate the relationship between functional tooth units (FTUs) and nutritional status. Methods: One hundred females (mean age: 72.4 ± 8.2 years) at four private care homes in Jakarta, Indonesia were interviewed and clinically examined. The oral examination included the assessment of teeth, prosthetic status, and number of FTUs. The total number of FTUs was further divided by tooth composition: natural tooth against natural tooth (NN‐FTUs), natural tooth against denture (ND‐FTUs), and denture against denture (DD‐FTUs). Nutritional status was evaluated using the body mass index (BMI) and the Mini Nutritional Assessment (MNA). Results: The mean numbers of teeth present, NN‐FTUs, ND‐FTUs, DD‐FTUs, and total FTUs were 13.1 ± 10.4, 1.7 ± 3.0, 1.2 ± 3.3, 0.4 ± 1.2 and 3.3 ± 4.4, respectively. The mean BMI and MNA scores were 24.8 ± 5.0 and 22.6 ± 2.8, respectively. Subjects with a normal BMI had a significantly higher total number of FTUs (3.6 ± 4.6) compared with underweight subjects (0.1 ± 0.3). Subjects with a normal MNA had a significantly higher number of NN‐FTU (2.6 ± 3.7) compared to those who were at risk or in a state of under‐nutrition (1.2 ± 2.4). Conclusion: This study revealed significant relationships between the number of FTUs and nutritional status. Keeping the posterior occlusion should be emphasized in order to maintain good nutritional status in older subjects.     

Relationship between non‐ulcerative functional dyspepsia,occlusal pairs and masticatory performance in partially edentulous elderly persons

doi: 10.1111/j.1741‐2358.2010.00377.x
Relationship between non‐ulcerative functional dyspepsia, occlusal pairs and masticatory performance in partially edentulous elderly persons Objective: To relate occlusal state, masticatory performance and non‐ulcerative functional dyspepsia. Background: In spite of the relationship between gastric disturbances and number of present teeth being recognised, the influence of the number of occlusal pairs and masticatory performance, expressed as median particle size, has not been considered. Materials and methods: Thirty‐eight subjects (mean age = 71.8 ± 7.7 years) diagnosed with non‐ulcerative functional dyspepsia were selected. A further 38 healthy subjects (mean age = 71.9 ± 7.0 years) acted as controls. Subjects were subdivided according to their number of occlusal pairs: (1) 0–4, (2) 5–9 and (3) 10–14. Masticatory performance was evaluated by using the sieving method. Data were analysed using 2‐way anova and Bonferroni post‐hoc, Chi‐square and Odd ratio tests. Results: Subjects presenting with non‐ulcerative functional dyspepsia and 0–4 occlusal pairs showed the lowest masticatory performance (p < 0.01). No association between the dyspepsia and the number of occlusal pairs (χ² = 0.48, p = 0.785) was observed, however results showed association between functional dyspepsia and masticatory performance (χ² = 4.07, p = 0.0437) presenting an odds ratio = 3.46 (Confidence Interval = 0.99–12.10). Conclusion: Changes in masticatory performance were associated with the presence of non‐ulcerative functional dyspepsia.     

THE EFFECT OF MASTICATORY PATTERNS AS MEASURED BY TIME-INTENSITY AND ELECTROMYOGRAPHY ON THE PERCEPTION OF BOVINE MUSCLE TENDERNESS

The relationship between perception of tenderness and chewing activity was explored using the Time-Intensity measurement of perception and electromyographic measurements of masseter muscle movement. Semitendinosus muscles from eight treatments of forage fed beef were evaluated by nine individuals. The Time-Intensity parameters of Area Under the Curve and Decrease Area were the most useful for treatment separation based on tenderness. Information was obtained from the electromyogram regarding the number of chews, time to chew and mastication rate. However, more work with EMG measurements is required to accurately study the effect of masticatory patterns on tenderness perception.     

Food choice by older people: the use of semi-structured interviews with open and closed questions

Objective: To evaluate difficulty chewing, consequent food choice and impacts using both open and closed questions within a semi‐structured interview format. Design: A cross‐sectional study using a semi‐structured interview (SSI) with open and closed questions Setting: Independently living people in South‐West London interviewed in their own homes Subjects: A group of 54, edentate people (mean age 82, R= 60‐93 years) were studied. Results: Most subjects (69%) expressed difficulty eating at least one type of food, half were unwilling to eat the foods they found difficult, others were conscious of cooking longer or cutting smaller in order to manage these foods, although no one accepted that they overcooked food. There were dramatic differences in the number of subjects expressing difficulty to chew various foods when responding to open and closed questions. Roast beef proved a good discriminator in this group of predominantly English subjects. The importance of the questioning process was also shown by the discrepancy of responses between variously prepared apples and the inability of any subjects to bite an unpeeled apple. Conclusions: For sensitive appraisal of food choice it is obviously essential to assess relevant foods, for the culture of the group being studied. Open questions provide a way of exploring which are the appropriate foods and food preparation as criteria to assess perceived chewing ability and treatment benefit. The semi‐structured interview method is particularly valuable for the study of older people. Closed questions provide different information which is also necessary to secure recall by older people.     

Oral health status of the elderly in a residential home in Turkey

Objectives: To determine the oral health status and treatment needs of elderly residents of a residential home in Ankara, Turkey. Background: Little is known about oral health problems of elderly living in the institutions. Methods: Among 216 elderly, 193 of them were interviewed and were clinically examined according to WHO criteria. Age, gender, educational and occupational status, oral hygiene practices, dental insurance, access to dental care and systemic diseases were recorded using a structured questionnaire. Coronal and root caries, periodontal disease, dental status and related treatment needs were assessed by two calibrated dentists. Results: The mean age of the subjects were 75.2 ± 8.3 in males, 79.1 ± 7.9 in females; 32.6% of subjects were dentate and the mean number of teeth was 3.7 ± 7.0 (median = 0). A functional dentition was present in 7.3% of subjects (≥20). The mean decayed, missing and filled teeth (DMFT) was 29.3 ± 5.8 (median = 32) and mean root caries was 2.2 ± 3.1 (median = 1.0). The major reason for tooth extraction was dental caries. Of the subjects, 20.7% had at least one untreated coronal caries and 18.1% root caries. The assessment of periodontal status according to CPI revealed that only four persons had nine healthy sextants with the score of ‘0’. Edentulousness was 67.4% while 11.9% of them lacked denture in both jaws. Conclusion: The results illustrated poor dental health and showed extremely high demand for the dental health services programmes for the elderly living in these institutions.     

Application of short-form oral health impact profile on elderly Japanese

Objectives: The purpose of this study was to use the oral health impact profile (OHIP‐14) to evaluate the impact of oral disease on the quality of life of a group of independently‐living elderly persons in an urban area of Japan. Subjects: A total of 1244 participants of the Senior Citizen's College, who attended the lectures once a week. They were community‐dwelling, independently‐living people over 60 years of age. Measurements: Japanese version of the short‐form OHIP‐14. Results: Internal reliability for the 14 items overall was very high (Cronbach's α = 0.95). Report of ‘painful aching’ and ‘uncomfortable to eat’ were the two most highly scored items using the mean sum OHIP‐14 score. A multiple logistic regression analysis indicated that the sum OHIP‐14 score had significant associations with self‐assessment of general health, dental status, and a perceived need for dental treatment. However, age, gender, dissatisfaction with financial status or education level was not significantly associated with the sum OHIP‐14. Compared with that of other countries, the items were ranked similarly, whereas the perceived magnitudes of the problems were quite different from other population. Conclusions: The OHIP‐14 in Japanese had a high internal reliability, was significantly associated with dental status and comparable ranking for items when compared with studies from other countries.     

Relationship between general health status and the change in chewing ability: a longitudinal study of the frail elderly in Japan over a 3-year period

Objectives: The aim of the present study was to identify the onset predictors of a change in chewing ability over a 3‐year period in the frail elderly. Methods: The subjects were frail elderly people living in southern Japan. Data were collected at baseline (n = 92) and 3 years later (n = 60). The dependent variable was a change in self‐rated chewing ability. The independent variables were age, gender, number of present teeth, dentition, maximum bite force (evaluated using a pressure‐sensitive foil), basic activities of daily living, self‐rated general health status, higher level of competence (evaluated using Tokyo Metropolitan Institute of Gerontology index), cognitive status (evaluated by revised Hasegawa Dementia Rating scale), and quality of life (evaluated using Philadelphia Geriatric Center morale scale) at baseline. To identify the most reliable predictors, bivariate analysis and multiple logistic regression analysis were performed, with the change of chewing ability as the dependent variable. Results: Bivariate analysis showed the change in chewing ability was significantly associated with general health status (p < 0.01), number of present teeth (p < 0.05) and maximum bite force (p < 0.01). Backward logistic regression analysis revealed that the most reliable predictor of a change in chewing ability at 3 years was general health status (odds ratio = 6.35, 95% CI = 1.69–23.88). Conclusion: The present findings suggest that general health status at baseline produces a change in chewing ability.     

The masseteric jaw-jerk reflex in older dentate subjects and edentulous denture wearers

The aim of the present study was to investigate any variations in the jaw-jerk reflex in edentulous subjects wearing complete dentures, compared to an age and sex-matched dentate group. The reflex was elicited by chin taps in 22 older dentate subjects with mean age 61.3 years and in 22 denture wearers with mean age 63.1 years. Surface electromyographic recordings were obtained from the masseter muscle of the preferred chewing side during mandibular rest and at moderate clenching (40% of the individual maximum clenching masseteric EMG activity). A jaw-jerk reflex was recorded in all subjects at least once, and its occurrence during clenching was reduced compared to rest. The occurrence of the reflex was however increased in the denture wearers in both experimental conditions, while minor differences were observed in the values for latency, duration and amplitude between the two dental status groups. These results suggest that under the present experimental conditions the periodontal ligament receptors might inhibit reflex activity. Multiple sensory interactions are expected in denture wearing. However a particular source of sensory feedback is provided by the stimulation of mucosal receptors from the acrylic denture base. Since the occurrence of the jaw-jerk at clench in the denture wearers was also reduced compared to the rest experiments, a potential inhibitory effect of the mucosal receptors can be speculated. According to the findings in the present study the loss of teeth and the rehabilitation with complete dentures do not severely disrupt the reflex activity investigated.