title: Changes over time in the periodontal status of young adults with no third molar periodontal pathology at enrollment.
abstract: OBJECTIVE
  To assess changes in periodontal status over time in subjects with all third molar region periodontal probing depths (PDs) of less than 4 mm at enrollment.
  
  
  METHODS
  Subjects were a subsample of young adults enrolled with 4 asymptomatic third molars in an institutional review board-approved longitudinal study. Full-mouth periodontal PD data, 6 sites per tooth, were measures of periodontal status. Data were aggregated to subject and jaw levels. A PD of 4 mm or greater was considered an indicator variable for periodontal pathology. Subjects were classified according to PD at follow-up: all PDs of less than 4 mm or at least 1 PD of 4 mm or greater. The demographic differences and the third molar anatomic position at baseline were compared to assess whether enrollment factors were related to the changes in periodontal pathology. The level of significance was set at .05.
  
  
  RESULTS
  One hundred six subjects had all third molar region PDs of less than 4 mm at enrollment and were aged 25 years on average. Of these, 38% had a change in third molar region periodontal status, with at least 1 third molar region PD of 4 mm or greater detected at a median follow-up of 4.1 years (interquartile range, 2.4-5.9 years). A PD of at least 4 mm was detected significantly more often in the mandibular third molar region than in the maxillary third molar region (P < .01). No significant differences in age, gender, education, or length of follow-up were detected between the 40 subjects with a change in periodontal status in the third molar region and the 66 subjects who remained periodontally healthy (P > .05). At follow-up, 50% of subjects with at least 1 PD of 4 mm or greater in the third molar region had at least 1 PD of 4 mm or greater in non-third molar regions as compared with 15% of subjects with all third molar region PDs of less than 4 mm (P < .01).
  
  
  CONCLUSIONS
  Periodontal pathology developing over time in healthy young adults was significantly more likely in the mandibular third molar region and mandibular non-third molars.
authors.affiliation: Department of Oral and Maxillofacial Surgery, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599-7450, USA.
authors.forename: George H
authors.initials: GH
authors.lastname: Blakey
authors.forename: Brent A
authors.initials: BA
authors.lastname: Golden
authors.forename: Raymond P
authors.initials: RP
authors.lastname: White
authors.forename: Steven
authors.initials: S
authors.lastname: Offenbacher
authors.forename: Ceib
authors.initials: C
authors.lastname: Phillips
authors.forename: Richard H
authors.initials: RH
authors.lastname: Haug
mesh_terms: D000328:Adult; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008334:Mandible; D008437:Maxilla; D008964:Molar, Third / Q000473:pathology*; D010510:Periodontal Diseases / Q000473:pathology*; D010512:Periodontal Index; D055815:Young Adult