Complete dentures associated with frailty among edentulous older Japanese people: A prospective analysis.

OBJECTIVE: This study aimed to explore the cross-sectional and prospective associations between self-reported functionality of complete dentures (FCD), satisfaction with complete dentures (SCD) and the ability to chew hard food (ACHF) on the one hand and the frailty index (FI) on the other hand among edentulous community-dwelling older Japanese people. METHODS: The study examined 770 edentulous participants of the Nihon University Japanese Longitudinal Study of Aging. The self-reported FCD, SCD and ability to chew six groups of food (from hardest to softest) with complete dentures were the independent variables at the baseline. The FI was computed including 40 deficits as the dependent variable at the baseline and 4 years later. Cross-sectional and prospective generalized linear regression models were fitted controlling for age, gender, marital status, education, working status and area of residence. RESULTS: The use of non-functional complete dentures and dissatisfaction with complete dentures were both associated with a higher FI cross-sectionally (3.9% [95% CI 2.2-5.6] and 3.2% [95% CI 1.5-4.9], respectively) and prospectively (3.9% [95% CI 2.0-6.0] and 3.3% [95% CI 1.3-5.3], respectively). Regarding the ability to chew, a higher FI at baseline was observed among those able to chew food of Group 2 (1.9%, [95% CI 0.1-3.7]) and Groups 4-6 (1.9%, [95% CI 0.1-3.7]), and a progressive increment in the FI, as the participants reported being able to chew softer groups of food at the follow-up (Group 2: 2.2% [95% CI 0.05-4.3]; Group 3: 3.6% [95% CI 1.2-6.0]; and Groups 4-6: 3.4 [95% CI 0.7-6.1]). CONCLUSION: Self-reported use of non-functional complete dentures, dissatisfaction with dentures and a reduced ACHF with complete dentures were associated with a higher FI both cross-sectionally and prospectively.

Factors associated with masticatory performance in community-dwelling older adults: A cross-sectional study.

BACKGROUND: Decreased masticatory performance leads to deterioration of overall health among older adults. However, maintaining and improving masticatory performance in ways other than maintenance of natural teeth and appropriate prosthodontic treatment remains unclear. If the factors related to the mixing and shearing abilities for masticatory performance are clarified, it may be possible to maintain and improve the masticatory performance of older adults. We aimed to clarify the association among mixing ability, shearing ability, and masticatory performance-related factors. METHODS: Of the 707 community-dwelling older adults in Kusatsu Town, Japan, 344 who had been treated for any dental defects were enrolled in this study. Masticatory performance was evaluated on the basis of mixing ability and shearing ability. The number of natural teeth and artificial teeth, occlusal force, tongue pressure, and oral diadochokinesis /ta/ were measured as masticatory performance-related factors. Their relationship with mixing ability, shearing ability, and masticatory performance-related factors was examined by means of Spearman rank correlation coefficient and path analysis. RESULTS: Among masticatory performance-related factors, the number of natural teeth, occlusal force, and tongue pressure were directly associated with both mixing ability and shearing ability. Moreover, mixing ability was also directly associated with shearing ability. CONCLUSIONS: Tongue pressure, which can be improved by means of training, is a masticatory performance-related factor associated with both mixing and shearing abilities. PRACTICAL IMPLICATIONS: Training for tongue pressure after proper prosthetic treatment may provide an effective means of maintaining and improving masticatory performance in older adults.

Intentions and Factors Regarding Selection of Workplace by Postgraduate Dental Trainees after Clinical Training.

The purpose of the present study was to investigate the reasons governing selection of geographical location of workplace by postgraduate dental trainees. We believe that such data would aid in the development of measures aimed at reducing regional disparities in the number of dentists. A total of 10 dental colleges and faculties in Japan were invited to participate in the study. Anonymous, self-completed questionnaire surveys were given to 739 dentists at 13 clinical training facilities following training in 2012 and 2013; 713 responses were analyzed. The items surveyed included the local population in the area in which they wished to work and whether they wanted to work in rural areas or remote islands. The most common response to the question regarding population was "medium-size cities" with a population of 100,000 to 300,000 people (67.3%). The largest number of respondents stated that they hoped to work in their hometown or a neighboring area (49.9%). A large percentage wished to work in medium-size cities, which may reflect the population of their hometowns. The current system allows dentists a free choice in becoming practitioners or hospital dentists on completion of training. This may explain why so many expressed a preference to work in their hometown or a neighboring area here. These results suggest that policies relying on increasing the supply of dentists as the sole solution to rural shortages are flawed.

Micromolar sodium fluoride mediates anti-osteoclastogenesis in Porphyromonas gingivalis-induced alveolar bone loss.

Osteoclasts are bone-specific multinucleated cells generated by the differentiation of monocyte/macrophage lineage precursors. Regulation of osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone-lytic diseases. Periodontitis is an inflammatory disease characterized by extensive bone resorption. In this study, we investigated the effects of sodium fluoride (NaF) on osteoclastogenesis induced by Porphyromonas gingivalis, an important colonizer of the oral cavity that has been implicated in periodontitis. NaF strongly inhibited the P. gingivalis-induced alveolar bone loss. That effect was accompanied by decreased levels of cathepsin K, interleukin (IL)-1ß, matrix metalloproteinase 9 (MMP9), and tartrate-resistant acid phosphatase, which were up-regulated during P. gingivalis-induced osteoclastogenesis. Consistent with the in vivo anti-osteoclastogenic effect, NaF inhibited osteoclast formation caused by the differentiation factor RANKL (receptor activator of nuclear factor κB ligand) and macrophage colony-stimulating factor (M-CSF). The RANKL-stimulated induction of the transcription factor nuclear factor of activated T cells (NFAT) c1 was also abrogated by NaF. Taken together, our data demonstrate that NaF inhibits RANKL-induced osteoclastogenesis by reducing the induction of NFATc1, ultimately leading to the suppressed expression of cathepsin K and MMP9. The in vivo effect of NaF on the inhibition of P. gingivalis-induced osteoclastogenesis strengthens the potential usefulness of NaF for treating periodontal diseases.

[Active life expectancy for elderly Japanese by chewing ability].

OBJECTIVE: Panel interview surveys of nationally representative elderly people aged 65 years or above in Japan were conducted three times at 2-year intervals since 1999 (Nihon University Japanese Longitudinal Study of Aging) to estimate health expectancy for males and females separately according to their chewing ability. METHOD: Multistate life table methods were applied to estimate health expectancy. Three health states, namely, active, inactive and dead, were defined according to the ability to perform specified daily activities. Living respondents were considered to be in an "inactive state" if they responded "very difficult" or "unable" for performance of at least one ADL or IADL. Otherwise they were considered to be in an "active state". 4,323 sampled persons who responded to the baseline survey were included in the study. Based on estimated transition probabilities over the survey period between active and inactive states, and active and inactive states to death, both population- and status-based multistate life tables were constructed according to chewing ability. Those who could chew relatively hard foods at the baseline survey were classified as Group A and those who could chew only relatively soft foods were classified as Group B. RESULTS: The population-based multistate life tables indicated that at age 65, total life expectancy was 19.3/23.2 (males/females) years for Group A and 16.7/21.1 years for Group B. Active life expectancy was 16.8/18.6 years and 13.6/16.3 years, and inactive life expectancy was 2.4/4.6 years and 3.1/4.8 years for Groups A and B respectively. A statistically significant difference was observed between the two groups only in terms of active life expectancy. From status-based multistate life tables, similar patterns were observed for those whose status at the baseline was "active". CONCLUSION: These results suggest that maintenance or recovery of sufficient chewing ability for elderly people is related to a longer total life expectancy and even more strongly related to a longer active life expectancy.

[Interrelationship among factors associated with drinking behaviors in dental students].

We analyzed the Kurihama Alcoholism Screening Test (KAST), the Adolescent Alcohol Involvement Scale (AAIS), the Fagerstroem Tolerance Questionnaire (FTQ), the Tokyo University ALDH2-Phenotype Screening Test (TAST), results of ethanol patch tests, the presence or absence of a smoking habit, and gender by "Hayashi's quantification theory, type II" in 415 senior students (232 males and 183 females) of a dental college between 2000 and 2003, and evaluated their relationships. When drinking education is given to dental students, both the prevention of acute alcohol intoxication by chugging and the prevention of alcohol dependence in students with drinking behavior suggesting this tendency are necessary. For acute alcohol intoxication, attention can be aroused in students with positive ethanol patch tests. However, there is no definite instruction method for the prevention of alcohol dependence. Therefore, we analyzed the relationships among drinking, smoking, and constitution based on data obtained during the 4 years when the above 3 types of surveys were performed. Plotting of the results of analysis showed that the students can be classified by the ethanol patch test and TAST into those with "alcohol-sensitive" constitution and those with "alcohol-tolerant" constitution. Most problem drinkers were "alcohol-tolerant". KAST showed plotting along the constitution axis from "normal drinking group" to "problem drinking borderline group" but a change in the angle to an L shape at the transfer point from "problem drinking borderline group" to "problem drinking group", showing more serious states along the smoking axis. These results suggest that drinking behavior is first regulated by alcohol- sensitive or alcohol-tolerate constitution, and alcohol-tolerate students with a smoking habit have alcohol dependence tendency, and tend to show serious problem drinking. Improvement in the drinking habit is necessary in alcohol-tolerate students with a smoking habit so that they will not develop alcohol dependence.

Association of natural tooth loss with genetic variation at the human matrix Gla protein locus in elderly women.

Natural tooth loss represents a major medical issue within the elderly population, since it impairs masticatory function critical for oral intake of essential nutrition. Contribution of genetic factors has been implicated in the determination of natural tooth loss; degree of reduction in number of natural teeth remaining intact (NTI) varies among individuals; thus, heterogeneity in NTI might reflect genetic variation within the population. One candidate gene, the matrix Gla protein gene (MGP), has been implicated in the pathogenesis of bone loss through a repression of bone/tooth formation. We have investigated a possible association between the CA repeat polymorphism at the human MGP gene locus and the NTI in 458 elderly Japanese women. In 916 chromosomes tested, ten alleles of the polymorphic nucleotide repeat were observed (designated A1-A10), among which five alleles were regarded as major alleles to be tested for the association. Twenty-seven women who possessed an A6 allele (164 bp) had significantly higher NTI than the remaining participants (n=431), who did not carry an allele of that size (mean: 10.0 teeth vs 5.6 teeth; P=0.007, Mann-Whitney test). An eight-year longitudinal follow-up study of NTI suggested that the genetic variations at the MGP locus did not affect the rate of tooth loss in the elderly period. These results suggest that genetic variation at the MGP gene locus is associated with some determinants for tooth loss in elderly women.

[Relationship between ethanol patch test and problem drinkers among dental students].

In 2000 and 2001, we carried out a drinking habit survey and the Ethanol Patch Test on 232 fourth-year dental students (128 males, 104 females). The results were statistically analyzed. For the survey, the students were asked to fill out, anonymously, the forms of the Tokyo-University ALDH2-Phenotype Screening Test (TAST), the Kurihama Alcoholism Screening Test (KAST), and the Adolescent Alcohol Involvement Scale (AAIS). The results of the subsequent Ethanol Patch test were evaluated by the students themselves. The Patch test demonstrated that 44.5% of males and 49.0% of females were positive to the test or ALDH2 deficient, the rest having the marker substance. According to the TAST results, ALDH2-deficient or TAST-positive (alcohol-intolerant) subjects accounted for 48.4% of males and 51.9% of females, the rest being ALDH2-present or TAST-negative students. Among the Patch test-positive group, the ratio of problem drinkers according to the KAST was 8.8% in males and 2.0% in females. The corresponding figures for the test-negatives group were; 22.5% in males; 7.5% in females, being higher than those for the test-positive group. Among the test-positive group, the ratio of problem drinkers scoring at least 42 points on the AAIS stood at 19.3% in males, 7.8% in females and among the test-negative group, the corresponding figures were; 21.1% in males; 13.2% in females, the difference from those for the other group being relatively small. The results of the Ethanol Patch test were related to those of the TAST and KAST, but not to the AAIS. The correlation between the Patch test and KAST indicates that the test-negatives are prone to become alcohol-dependant. Though the results of the Patch test and those of the AAIS were not related, the findings show that some alcohol-intolerant university students are drinking excessively.