Measuring clinical attachment: reproducibility of relative measurements with an electronic probe

During the past few years, improvements in detecting longitudinal changes in clinical attachment or alveolar bone density have been introduced. For example, constant-force electronic probes and computer-assisted subtraction analysis of longitudinal radiographs have been reported to be more sensitive and reproducible in detecting changes in clinical attachment or alveolar bone density, respectively. Use of these new technologies requires that sources of measurement error be identified and their contribution quantified. This study investigated the reproducibility of a constant-force electronic probe in a careful clinical setting. Measurements were performed from individually fabricated acrylic stents. Three groups of subjects were selected for the study: 10 adults without oral disease, 10 adults with gingivitis, and 10 adults with moderate periodontitis. Four probing designs were employed to investigate the reproducibility of the probe. In design A, the probe tip was left in the sulcus between successive probings. In design B, the probe tip was removed from the gingival margin between probings but the next probing followed immediately. In design C, successive whole-mouth probings were interrupted by a 5-minute interval and a mouth rinse. In design D there was a 4-week interval between each successive probing. Three measurements were taken at each site for each design. The main purpose of this study was to identify variance components in the attachment level variation. The maximum probing error standard deviation ranged from 0.2 to 0.3 mm depending on the periodontal health of the subject. This level of variation is considerably smaller than that found in most previous studies.(ABSTRACT TRUNCATED AT 250 WORDS)