Comparison of gingival attachment level measurements with an automated periodontal probe and a pressure‐sensitive probe

An automated periodontal probe (APP) has been developed which measures gingival attachment level using the occlusal or incisal surface of the tooth as a fixed landmark and which transfers data directly to a computer. To assess the precision of data obtained with the new probe, duplicate measurements of gingival attachment level were made. Differences between paired data (d values) were compared with those obtained with a pressure‐sensitive probe (PSP) in order to test the hypothesis that there is no significant difference in the distribution of d values between the two probes. Duplicate measurements were made 1 wk apart around 220 teeth in 19 patients using the automated probe and around 218 teeth in 24 patients with the pressure‐sensitive probe. A probing force of 0.50 N was used for both probes. Greater than 83% of the d values obtained with the automated probe were less than 0.5 mm. There was no significant difference between the frequency distribution of d values for the automated probe (d = 0.28 ± 0.28 mm) and the pressure‐sensitive probe (d = 0.23 ± 0.42 mm). Further, no significant differences between the two different probes were observed in maxillary, mandibular and anterior teeth. The PSP did exhibit slightly fewer d values greater than 1.0 mm for posterior teeth in comparison to the APP (0.9% for PSP, 4.4% for APP). However, d values obtained with the APP exhibited significantly less variance than the PSP for all areas of the mouth (p < 0.005). These findings support the null hypothesis that the precision of data obtained with the automated probe is not significantly different from the pressure‐sensitive probe. The automated nature of the new probe and its utility in providing rapid, unbiased and precise measurements of gingival attachment level suggest that it would be very useful for the study of the natural history of periodontitis in human populations.