Overview of clinical trials of periodontal diagnosis methods and devices

Changing views of the pathogenesis and progression of the periodontal diseases and new modalities for treatment have stimulated a plethora of physical, biochemical, microbiologic, and immunologic diagnostic procedures, tests, and devices. Clinical trials address needs for: 1) screening tests and risk assessment for disease susceptibility; 2) identification of active and progressive disease sites; 3) making therapeutic decisions; 4) monitoring therapy; 5) establishing a maintenance schedule; and 6) prognosis assessment. Needs and priorities of general, specialty, and public health practitioners differ. Validation of tests proceeds in a hierarchy of study designs from cross sectional and case control studies to retrospective and prospective longitudinal multi-center trials. For broad-scale application, randomized controlled trials (and eventual meta-analysis) will be required. Design issues are those common to all clinical trials in periodontics plus special considerations depending on type of test and its intended use. For diagnostic tests, recommended surrogate endpoints are attachment and alveolar bone levels-the traditional "gold standards." Validation of diagnostic tests is best accomplished by generation of 2 x 2 contingency tables to calculate sensitivity and specificity, positive and negative predictive values, relative and absolute risks, and odds rations. Each has a place-depending on the clinical situation and needs of the clinician.