title: Moderate- to long-term periodontal outcomes of subjects failing to complete a course of periodontal therapy.
abstract: BACKGROUND
  The current retrospective cross-sectional study investigated 5-18-year treatment outcomes in subjects who did not complete a recommended course of periodontal therapy.
  
  
  METHODS
  Sixty-five subjects who voluntarily discontinued therapy were recalled. The subjects' demographic data and dental history since discontinuation of periodontal treatment were collected via questionnaires. The subjects' periodontal condition, radiographic data and individual tooth-based prognosis at pre-discontinuation and recall were compared.
  
  
  RESULTS
  A total of 229 teeth had been lost over time, mainly due to periodontal reasons. Upper and lower molars were most frequently lost. Rate of tooth loss (0.38/patient per year) was comparable to untreated patients. Deterioration in periodontal health in terms of increased percentage of sites with bleeding on probing (BOP) and sites with probing pocket depths (PPD) of 6 mm or more at re-examination was observed. Positive correlations were found between tooth loss and: (i) years since therapy discontinued; (ii) percentage of sites with PPD of 6 mm or more at pre-discontinuation; and (iii) at re-examination. Percentage of sites with PPD of 6 mm or more at recall was positively correlated with periodontal tooth loss and negatively correlated with percentage of sites without BOP.
  
  
  CONCLUSIONS
  Patients not completing a course of periodontal therapy are at risk of further tooth loss and deterioration in periodontal conditions over time.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.|Faculty of Dentistry, The National University of Malaysia, Kuala Lumpur, Malaysia.
authors.forename: V
authors.initials: V
authors.lastname: Goh
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: P P
authors.initials: PP
authors.lastname: Hackmack
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: E F
authors.initials: EF
authors.lastname: Corbet
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: W K
authors.initials: WK
authors.lastname: Leung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008963:Molar; D010510:Periodontal Diseases / Q000628:therapy*; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000601:surgery*; D011379:Prognosis; D012189:Retrospective Studies; D016388:Tooth Loss / Q000209:etiology* / Q000628:therapy; D016896:Treatment Outcome
keywords: Initial periodontal therapy; periodontal disease; prognosis; radiograph; supportive periodontal therapy