title: Variance component modeling of attachment level measurements.
abstract: The purpose of this study was to investigate the influence of within subject and within tooth variability of attachment-level measurements on hypothesis testing. Full-mouth attachment-level measurements were obtained at 4 sites per tooth in early onset periodontitis subjects (both localized N = 89 and generalized N = 139) and adult periodontitis subjects (N = 309). Variance component models utilizing iterative generalized least squares were employed to estimate the % of variance distributed at the level of the site, tooth and subject in the 3 subject populations. The data indicate that a significant % of the variance is distributed within the tooth and the subject. Ignoring the variance attributable to teeth or subjects can result in inappropriately low type I error rates for hypothesis testing. Thus, both the subjects and the tooth must be considered in the modeling of attachment level measurements. Also in studies in which a limited number of samples are taken, data analysis would be simplified if these samples were taken from different teeth.
authors.affiliation: Clinical Research Center for Periodontal Diseases, Virginia Commonwealth University, Richmond.
authors.forename: J C
authors.initials: JC
authors.lastname: Gunsolley
authors.forename: D A
authors.initials: DA
authors.lastname: Williams
authors.forename: H A
authors.initials: HA
authors.lastname: Schenkein
mesh_terms: D000328:Adult; D010520:Aggressive Periodontitis / Q000175:diagnosis / Q000473:pathology; D016001:Confidence Intervals; D003774:Dental Plaque Index; D005260:Female; D005884:Gingival Hemorrhage / Q000175:diagnosis / Q000473:pathology; D005891:Gingivitis / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008954:Models, Biological; D017622:Periodontal Attachment Loss / Q000175:diagnosis* / Q000473:pathology*; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000175:diagnosis* / Q000473:pathology*; D010518:Periodontitis / Q000175:diagnosis* / Q000473:pathology*; D012044:Regression Analysis; D015203:Reproducibility of Results; D014070:Tooth / Q000473:pathology