Comparison of manual and pressure-controlled periodontal probing

Over 25,000 sites around natural teeth in three stages of periodontal therapy (prior to instrumentation, following closed subgingival instrumentation and following surgical therapy) were independently probed by two examiners. Examiner A used a conventional periodontal probe with uncontrolled pressure. Examiner B used an identical probe tip mounted in a handle which controlled vertical probing force at 50 g. The pressure-controlled technique produced significantly deeper clinical probing measurements on the direct facial and lingual aspects of teeth regardless of the stage of periodontal therapy that had been completed. Manual probing obtained deeper measurements on the distal-lingual aspects of teeth in the posterior regions which had not received surgical therapy. The percentage match between probing depths obtained by the two methods declined as the probing depths increased. Control of vertical force during probing may provide a more objective method of monitoring periodontal status during longitudinal trials.