Although poor oral health influences the occurrence of pulmonary infection in elderly people, it is unclear how the degree of oral health is linked to mortality from pulmonary infection. Therefore, we evaluated the relationship between oral health and four-year mortality from pneumonia in an elderly Japanese population. The study population consisted of 697 (277 males, 420 females) of the 1282 individuals who were 80 years old in 1997. Data on oral and systemic health were obtained by means of questionnaires, physical examinations, and laboratory blood tests. One hundred eight of the study persons died between 1998 and 2002. Of these, 22 deaths were due to pneumonia. The adjusted mortality due to pneumonia was 3.9 times higher in persons with 10 or more teeth with a probing depth exceeding 4 mm (periodontal pocket) than in those without periodontal pockets. Therefore, the increase in teeth with periodontal pockets in the elderly may be associated with increased mortality from pneumonia.

Streptococcus mutans is implicated as a major etiological agent in human dental caries, and one of the important virulence properties of this organism is its ability to form biofilms (dental plaque) on tooth surfaces. We examined the role of autoinducer-2 (AI-2) on S. mutans biofilm formation by constructing a GS-5 luxS-null mutant. Biofilm formation by the luxS mutant in 0.5% sucrose defined medium was found to be markedly attenuated compared to the wild type. Scanning electron microscopy also revealed that biofilms of the luxS mutant formed larger clumps in sucrose medium compared to the parental strain. Therefore, the expression of glucosyltransferase genes was examined and the gtfB and gtfC genes, but not the gtfD gene, in the luxS mutant were upregulated in the mid-log growth phase. Furthermore, we developed a novel two-compartment system to monitor AI-2 production by oral streptococci and periodontopathic bacteria. The biofilm defect of the luxS mutant was complemented by strains of S. gordonii, S. sobrinus, and S. anginosus; however, it was not complemented by S. oralis, S. salivarius, or S. sanguinis. Biofilm formation by the luxS mutant was also complemented by Porphyromonas gingivalis 381 and Actinobacillus actinomycetemcomitans Y4 but not by a P. gingivalis luxS mutant. These results suggest that the regulation of the glucosyltransferase genes required for sucrosedependent biofilm formation is regulated by AI-2. Furthermore, these results provide further confirmation of previous proposals that quorum sensing via AI-2 may play a significant role in oral biofilm formation.Quorum sensing (QS) is a process whereby bacteria communicate with one another by means of the secretion of chemical signal molecules called autoinducers (AIs) (3,4,35,38). In the bioluminescent gram-negative marine bacterium Vibrio harveyi, two distinct AIs, AI-1 (6, 9) and AI-2, regulate light emission (36). LuxS is an enzyme involved in the catabolism of S-adenosylmethionine and converts ribose homocysteine into homocysteine and 4,5-dihydroxy-2,3-pentanedione, the precursor of 46,51). This system has been referred to as an interspecies quorum system and may operate as a universal quorum system for many bacteria possessing the characteristic luxS gene (5). The luxS gene is highly conserved across a diverse range of gram-negative and gram-positive bacterial species, and AI-2 is produced by many of these species. QS enables a population of bacteria collectively to regulate gene expression including expression of virulence factors (21, 39), competence for genetic transformation (1, 28, 37), conjugal DNA transfer (20,52,56), and the production of antibiotics and secondary metabolites (31, 49), as well as biofilm formation (13). However, more recent investigations have also indicated that AI-2 production is regulated at the level of LuxS substrate availability and not at the level of luxS expression. Consequently, AI-2-dependent signaling can also reflect the metabolic state of the cell and not necessarily cell density (7).Biofilms are se...

There is a relationship between perceived chewing ability (number of foods considered chewable) and physical fitness in this 80-year-old population. Chewing ability may be an independent predictor of physical fitness, thus preventative dental care aimed at preserving chewing ability may be able to enhance activities of daily life and quality of life in very elderly individuals.

Background and Objectives Identification of modifiable factors for mild cognitive impairment (MCI) is important since individuals with MCI are at a high risk of dementia and disability. Previous studies have suggested a potential association between periodontitis and cognitive impairment, but the results remain inconclusive. We designed a 5‐year longitudinal study to explore the association between MCI and periodontitis and periodontal inflammation in older adults. Methods This study included 179 community‐dwelling dentate individuals (62 men and 117 women, average age: 80.1 years). A full‐mouth periodontal examination at six sites per tooth was performed at baseline. Case definitions provided by the European Workshop in Periodontology Group C (EWP definition) and the Centers for Disease Control/American Academy of Periodontology (CDC/AAP definition) were used to define severe periodontitis. Additionally, the periodontal inflamed surface area (PISA), reflecting the amount of inflamed periodontal tissue, was calculated using clinical periodontal parameters. Follow‐up cognitive examinations for MCI diagnosis were performed by neurologists 1, 2, 3, and 5 years after baseline. Odds ratios (ORs) for MCI according to the presence of periodontitis and periodontal inflammation at baseline were calculated using multilevel mixed‐effects logistic regression. Results At baseline, 56.4% and 27.4% of the participants had severe periodontitis by the EWP and CDC/AAP definitions, respectively. After adjusting for follow‐up period and other baseline health characteristics (age, sex, smoking status, educational level, physical activity level, obesity, depression, and diabetes), severe periodontitis by either definition was significantly associated with MCI (for the EWP definition: adjusted OR = 3.58, 95% confidence interval [CI] = 1.45‐8.87; for the CDC/AAP definition: adjusted OR = 2.61, 95% CI = 1.08‐6.28). Periodontal inflammation assessed by PISA was also significantly associated with a higher OR for MCI (adjusted OR = 1.05, 95% CI = 1.01‐1.10, per 10‐mm2 increase in PISA). Conclusion Severe periodontitis and periodontal inflammation were associated with incident MCI among older community‐dwelling men and women.

Limited information is available on the temporal association between dentition status and dietary intake. The aim of this 5-year prospective cohort study was to investigate whether impaired dentition was associated with subsequent decline in dietary intake in older Japanese adults. Two hundred and eighty-six community-dwelling Japanese individuals, all aged 75 years at baseline, were included in the study. Functional tooth units (FTUs), defined as a pair of opposing natural or prosthetic teeth excluding third molars (range: 0-14), were counted on the basis of baseline dental examinations. Individuals with ≤5 FTUs were defined as having impaired dentition. Dietary intake was assessed at baseline and 5 years later, using a validated dietary questionnaire. Robust regression analyses were used to evaluate the differences in change in dietary intake between participants with and without impaired functional dentition, after adjustment for potential confounders. Sixty-one study participants (21·3 %) were defined as having impaired dentition. Overall, mean values for all estimated dietary variables (energy, nutrients and food groups) declined over time. Notably, individuals with impaired dentition demonstrated a significantly (P < 0·05) greater degree of decline in the intake of multiple nutrients (protein, sodium, potassium, calcium, vitamin A, vitamin E and dietary fibre) and food groups (vegetable and meat) than those without impaired dentition, after adjusting for potential confounders. The results of this study describe the temporal association of impaired dentition with the decline in selected nutrient and food group intake among older Japanese adults.

BackgroundRecent studies suggest that tonsilloliths are clinically related to halitosis and tonsillar abscess. Based on our empirical knowledge, tonsilloliths are relatively commonly encountered in daily clinical practice. It has been reported that the detection rate of tonsilloliths was under 24% in previous reports, although experience suggests otherwise. The purpose of the study was to evaluate the prevalence and characteristics of tonsilloliths using computed tomography (CT). In addition, the possible causes of low detection rates on panoramic radiographs were evaluated based on comparisons between CT images and panoramic radiographs in order to elucidate the limitations of visualizing the area around the palatine tonsils on panoramic radiographs.Methods482 pairs of CT images and panoramic radiographs were retrospectively assessed with respect to the presence and characteristics of tonsilloliths. In addition, the causes in cases of disagreement between the two modalities were analyzed.ResultsThe detection rate of tonsilloliths was 46.1% using CT scans, unlike previous reports. The characteristics of tonsillolith were dot-like figures with about 300-500 Hounsfield units within the palatine tonsil under the soft palate. The most common length of tonsilloliths was about 3 or 4 mm. As the subjects aged, the detection rate increased gradually. A significant difference in the tonsillolith detection rate was found between the over and under 40-year-old groups (p < 0.0001). However, the detection rate of tonsilloliths was only 7.3% on panoramic radiographs. A significant correlation was observed between the detection rate of tonsilloliths on panoramic radiographs and CT number (Spearman r = 0.429), size, (Spearman r = 0.318), and number of tonsilloliths (Spearman r = 0.333).ConclusionThe present results suggest that tonsilloliths are relatively more common than previously suggested. However, panoramic radiographs detect only a small percentage of palatine tonsilloliths. The low detection rates on panoramic radiographs might be related to the degree of calcification, size, and number of tonsilloliths.

The findings of the present study indicated that 85-year-old participants with > or = 20 teeth had better subjective physical health than those with < or = 19 teeth.

The symbiotic effects of P. gingivalis, T. denticola, and T. forsythia, which coaggregate and exist concomitantly in subgingival biofilms, may be associated with the local development of periodontitis.