Impact of number of functional teeth on independence of Japanese older adults.

AIM: To examine the relationship between the number of present and functional teeth at baseline and future incidence of loss of independence. METHODS: Participants were community-dwelling older individuals who participated in a comprehensive geriatric health examination conducted in Kusatsu town, Japan, between 2009 and 2015. The primary endpoint was the incidence of loss of independence among participants, defined as the first certification of long-term care insurance in Japan. The numbers of present and functional teeth at baseline were determined via an oral examination. Demographics, clinical variables (e.g., history of chronic diseases and psychosocial factors), blood nutritional markers, physical functions, and perceived masticatory function were assessed. RESULTS: This study included 1121 individuals, and 205 individuals suffered from loss of independence during the follow-up period. Kaplan-Meier estimates of loss of independence for participants with smaller numbers of present and functional teeth were significantly greater than for those with larger numbers of teeth. Cox proportional hazard analyses indicated that a smaller number of present teeth was not a significant risk factor after adjusting for demographic characteristics. However, the number of functional teeth was a significant risk factor after the adjustment (hazard ratio: 1.975 [1.168-3.340]). Additionally, higher hazard ratios were observed in other adjusted models, but they were not statistically significant. CONCLUSIONS: The number of functional teeth may be more closely related to the future incidence of loss of independence than the number of present teeth. This novel finding suggests that prosthodontic rehabilitation for tooth loss possibly prevents the future incidence of this life-event. Geriatr Gerontol Int 2022; 22: 1032-1039.

Number of functional teeth more strongly predicts all-cause mortality than number of present teeth in Japanese older adults.

AIM: Previous studies on the association between intraoral conditions and mortality in community-dwelling older individuals reported that fewer present teeth (PT) are significant risk factors for mortality. However, how the number of PT relative to the number of functional teeth (FT), including both present and rehabilitated teeth, influences mortality has not been investigated fully. This study examined the impact of the number of FT on mortality among community-dwelling Japanese older adults. METHODS: This study was a retrospective, observational and population-based follow-up study, which examined 1188 older individuals who participated in an annual geriatric health examination from 2009 to 2015. The average follow-up period was 1697.0 ± 774.5 days. The primary outcome was all-cause mortality at follow-up. The numbers of PT and FT of each participant were counted during an oral examination. In addition, demographics, clinical variables, blood nutrient markers, physical functions and perceived masticatory function were measured. RESULTS: Kaplan-Meier analysis, followed by a log-rank test, revealed that fewer PT (P < 0.001) and FT (P = 0.002) were significantly associated with a reduced survival rate. Cox's proportional hazard analysis indicated that the number of FT, but not the number of PT, was a significant independent mortality risk factor after adjusting for demographics, clinical variables, nutrient markers and physical functioning (P = 0.036, hazard ratio: 2.089). CONCLUSIONS: Current results suggest that the number of FT more strongly predicts all-cause mortality than the number of PT among community-dwelling older adults. Further studies are necessary to consider the confounding of socioeconomic status and disability status. Geriatr Gerontol Int 2020; ••: ••-••.

Fate of Worn-Out Functional Teeth in the Upper Jaw Dentition of Sicyopterus japonicus (Gobioidei: Sicydiinae) During Tooth Replacement.

Mochizuki and Fukui (Jpn J Ichthyol 30 () 27-36) studied the development and replacement of the upper jaw teeth in a Japanese fish species, Sicyopterus japonicus (Gobioidei: Sicydiinae), and they reported that worn-out functional teeth in the upper jaw were not shed outside the skin but were taken into the soft tissue of the upper jaw and completely resorbed there. To date, however, this phenomenon appears poorly documented. Furthermore, the mechanism for the resorption of these teeth remains to be determined. In this study, we examined this phenomenon by using 3D microcomputed tomography (m-CT), scanning electron microscopy (SEM), and various techniques of light (LM) and electron (EM) microcopy. This study demonstrated that the upper jaw dentition of this fish was more or less simultaneously replaced with the replacement occurring during short time periods and that the lingual movement of the replacement teeth to the functional tooth position advanced simultaneously in a given row. Furthermore, our study also revealed that many worn-out functional teeth were engulfed by the oral epithelium, invaginated into the lingual shallow ditch of the premaxilla, and were resorbed/degraded completely by numerous foreign body giant cells rather than by odontoclasts during periods of at least three intervals of tooth replacement. The complete resorption/degradation of worn-out functional teeth in the soft tissue of the upper jaw suggests the possibility of the reuse of their components (minerals such as Ca and P, including Fe) for rapid and successional production of new replacement teeth in the upper jaw of adult S. japonicus. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:111-124, 2018. © 2017 Wiley Periodicals, Inc.

Can the number of functional teeth potentially affect cognitive function? / 대한구강보건학회지

OBJECTIVES: With the growing elderly population, there is an increasing interest in the oral and general health of elderly individuals. Loss of teeth is representative of oral disease in elderly individuals and is associated with medical and dental problems. The purpose of this study was to investigate the relationship between the number of remaining functional teeth and cognitive function. METHODS: A total of 456 (111 public health centers, 261 senior centers, 84 sanatoriums) older adults (aged ≥65 years) residing in Korea were included. A mental health nurse examined the cognitive function using the Korean version of the Mini-Mental State Examination. A dentist examined the number of functional teeth and denture status through an oral examination, while a dental hygienist surveyed the subjective masticatory level using a questionnaire. RESULTS: The mean age of the participants was 79.5 years (range 65–97 years), and 76.1% of them were women. Participants with a small number of functional teeth had lower cognitive function. In these participants, the odds ratio with poor cognitive function was 2.30 times higher; it was 2.74 times higher after adjusting for age, sex, residence, education, and denture use, and was statistically significant. CONCLUSIONS: Our study suggested that the number of functional teeth was associated with cognitive function in the Korean elderly population.

Time and order of eruption of first functional teeth in the upper jaw of post-larval life of Sicyopterus japonicus (Gobiidiae: Sicydiinae) during cranial metamorphosis at the time of river recruitment.

OBJECTIVE: The present study was aimed at elucidating the time and order of eruption of first functional teeth in the upper jaw of post-larval life of Sicyopterus japonicus (S. japonicus) during cranial metamorphosis at the time of river recruitment. DESIGN: Fishes were caught at the post-larval stage at a river mouth and maintained for 7 days in a water tank. Each of 10 specimens was evaluated every day for 7 days by using microcomputed tomography, scanning electron microscopy, and light microscopy with peculiar attention to the development of the upper jaw teeth. RESULTS: Fishes caught at the river mouth were mostly transparent, with a rostral terminal mouth, and no teeth could be found in either the upper or lower jaw. At 2 days after collection, the mouth position changed from terminal to subterminal, resulting from a change in head shape. The initial eruption of first functional teeth was detected at the anterior two-thirds region of each upper jaw. These teeth erupted in adjacent positions, most had a tricuspid crown, and they represented miniature versions of adult teeth. At 5 days, the position of the mouth became further relocated from terminal rostral to ventral. The number of erupted teeth increased, followed by spreading of them anteriorly and posteriorly. At 7 days, they formed a single row of close-set tricuspid teeth along the entire length of each upper jaw. CONCLUSIONS: The present study demonstrated that even under laboratory conditions a rapid and drastic cranial metamorphosis took place within a week after the time of collection of post-larval S. japonicus from a river. The eruption of first functional teeth in the upper jaw of S. japonicus, which teeth are adapted to scraping algae off the substrate, was initially detected at 2 days after collection, and first functional dentition of the upper jaw was set up within 7 days after it.

Prevalencia de dentición funcional en ancianos mexicanos / Prevalence of functional teeth in Mexican elderly

Objetivo: Determinar la prevalencia de dentición funcional (DF) y su distribución a través de diversas variables clínicas, sociodemográficas y socioeconómicas de una muestra de ancianos mexicanos. Material y métodos En un estudio transversal se incluyeron 139 adultos de 60 años y más de 2 asilos y un club de ancianos de la ciudad de Pachuca, Hidalgo, México. La variable dependiente fue la dentición funcional; operacionalmente categorizada como: 0 = sujetos con menos de 21 dientes presentes en la boca y 1 = sujetos con 21 o más dientes en la boca, excluyendo prótesis. Las variables sociodemográficas, socioeconómicas y conductuales se recogieron a través de un cuestionario. Las variables clínicas fueron recabadas por un examinador capacitado y estandarizado. El análisis se realizó utilizando pruebas no paramétricas en Stata. Resultados El promedio de edad fue de 79,06 +/- 9,78. La mayoría de los sujetos incluidos fueron mujeres (69,1 por ciento). La prevalencia de dentición funcional fue de 10,1 por ciento. En el análisis bivariado observamos lo siguiente: los sujetos con DF tuvieron menor edad (p < 0,05); entre las mujeres se observó mayor prevalencia de DF (p < 0,05); las personas con pareja presentaron más alto porcentaje de DF (p < 0,05); la prevalencia de DF fue diferente a través de los tipos de asilamiento (p < 0,05). Conclusiones Los datos sugieren una baja prevalencia de dentición funcional en esta muestra de adultos mayores. Este estudio demuestra que la DF varía en función de variables sociodemográficas.

Objective: To determine the prevalence of functional teeth (FT) and their distribution using clinical, demographic, and socioeconomic variables in a sample of Mexican elderly. Material and methods This cross-sectional study of 139 adults aged 60 years and older was conducted in two nursing homes and one club in Pachuca, Hidalgo, Mexico. The dependent variable was FT, and participants were operationally categorised as 0 (having less than 21 teeth) or 1 (having 21 or more teeth). Those categorised as 1 comprised the FT group. Sociodemographic, socioeconomic, and behavioural variables were collected using a questionnaire. Clinical variables were collected by a trained examiner using a standardised examination. Analysis was performed using non-parametric tests in Stata. Results The mean age was 79.06 +/- 9.78 years. Most (69.1 percent) of the participants were women. The prevalence of FT was 10.1 percent. In the bivariate analysis, it was observed that the FT group was younger (p < .05), women displayed a greater prevalence of FT than men (p < .05), as did those involved in a relationship compared to being single (p < .05), and FT prevalence differed by type of isolation (p < .05). Conclusions The prevalence of FT is low among nursing home residents and club members, and it varies with age, sex, relationship status, and type of isolation.