title: Option-4 algorithm for third generation disc probe: agreement of selected site-specific relative attachment level measurements and detection of longitudinal site-specific attachment level change.
abstract: BACKGROUND
  Longitudinal site-specific attachment level change (SSAC), identified from serial relative attachment level measurements (RAL), is the principal indicator of progression/regression of periodontal diseases. Many variables confound RAL reproducibility and affect measurement error. The Option-4 algorithm was designed to reduce measurement error and improve accuracy and sensitivity of SSAC detection. The study aimed to evaluate the performance of the Option-4 algorithm.
  
  
  METHODS
  A precalibrated clinician recorded full mouth RAL with a third generation disc probe on 4 occasions over 6 months in 16 subjects (mean age 48.1 years) with moderately advanced chronic adult periodontitis (2,312 sites). Option-4 allowed up to 4 RAL recordings per site per visit until 2 values had differences < or =1.0 mm and their mean was < or =1.0 mm from the previous visit mean: the clinician made the selection if these criteria were unfulfilled.
  
  
  RESULTS
  Within-visit agreement < or =1.0 mm was > or =99.6%: all within-visit correlation coefficients = 0.98 (P<0.001). At each visit, mean difference in Option-4 values was < 0.05 mm, mean absolute difference (ignoring direction) was < or =.34 mm. Mean site-specific variances ranged from 0.092 mm2 to 0.097 mm2 across all visits. Subject thresholds for site-specific attachment level change (from estimated 95% confidence limits of visit 1 data) ranged from 0.52 mm to 0.67 mm. Linear SSAC (by linear regression) and between-visit patterns of SSAC were investigated. SSAC was detected in 100% subjects and at 51.0% measured sites. Linear SSAC (R2 > or =0.90: P < or =0.05) occurred at 105 sites (4.5%): 32 sites (1.4%) deteriorated, 73 sites (3.1%) improved. Between-visit SSAC occurred at 1,074 sites (46.5%): 391 sites (16.9%) deteriorated, 295 sites (12.8%) improved, and 388 sites (16.8%) showed exacerbation/remission patterns.
  
  
  CONCLUSIONS
  The Option-4 algorithm produced high RAL agreement. Site-specific attachment level change was detected in both directions in 100% subjects and at 51.0% measured sites.
authors: Clinical Practice, Chelmsford, Essex, UK.
authors: H J
authors: HJ
authors: Breen
authors: P A
authors: PA
authors: Rogers
authors: R E
authors: RE
authors: Slaney
authors: I R
authors: IR
authors: Gillett
authors: N W
authors: NW
authors: Johnson
mesh_terms: D000328:Adult; D000465:Algorithms; D002908:Chronic Disease; D016001:Confidence Intervals; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D010517:Periodontics / Q000295:instrumentation*; D010518:Periodontitis / Q000145:classification / Q000473:pathology; D012074:Remission Induction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method