title: Longitudinal study on periodontal conditions in healthy elderly people in Japan.
abstract: OBJECTIVE
  A strategy for the control of periodontal disease progression is required to prevent tooth loss in older people. However, detailed epidemiological data on periodontal conditions in elderly people is limited. The purpose of the present study is to describe the natural history of periodontal disease and to evaluate the intraoral factors relating to the disease progression in systemically healthy elderly people.
  
  
  METHODS
  In the cross-sectional study, 599 and 162 subjects aged 70 and 80 years, respectively, were examined. Of those subjects aged 70 years, 436 (73%) participated in the 2-year longitudinal study. Pocket depth (PD) and attachment level (AL) were measured for all functioning teeth at six sites per tooth. In the cross-sectional study, AL of 4 mm or greater and 7 mm or greater were defined as moderate and severe disease, respectively. In the longitudinal study, a change in AL of 3 mm or greater at each site was defined as periodontal disease progression.
  
  
  RESULTS
  In the cross-sectional study, 97.1% of the subjects had at least one site of AL of 4 mm or greater (4+ mm). The prevalence of AL of 7 mm or greater (7+ mm) was 47.9%, with 2.8 affected teeth per person in those with AL 7+ mm. These findings reveal that periodontal disease is extremely widespread in the elderly population. However, very few had many teeth with severe periodontal conditions. In the longitudinal study, 75.1% experienced attachment loss of 3 mm or greater (3+ mm) during the 2-year study period. Of those subjects who experienced attachment loss, a mean of 4.7 teeth exhibited attachment loss. Multivariate logistic regression showed that both the highest AL in each tooth at baseline and abutment teeth for removable partial dentures were significantly related to periodontal disease progression as well as tooth loss incidence.
  
  
  CONCLUSIONS
  These results suggest that teeth with poor periodontal conditions as well as abutment teeth for removable partial dentures were significant intraoral factors relating to periodontal disease progression as well as tooth loss.
authors.affiliation: Division of Preventive Dentistry, Department of Oral Health Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata City, Japan. hirotomi@dent.niigata-u.ac.jp
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Hirotomi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshihara
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yano
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ando
authors.forename: Hideo
authors.initials: H
authors.lastname: Miyazaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D017622:Periodontal Attachment Loss / Q000473:pathology; D010510:Periodontal Diseases / Q000453:epidemiology*; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000473:pathology; D015995:Prevalence; D011795:Surveys and Questionnaires