Manual and Electronic Detection of Subgingival Calculus: Reliability and Accuracy

Calculus consists of mineralised dental biofilm on the surfaces of teeth and dental prosthesis, the location of which can be detected by using a periodontal or an electronic probe. Detection of subgingival calculus is critical for successful treatment outcome in the management of periodontal patients. The aim of this study was to detect subgingival calculus using manual and electronic probe and to compare the reliability and the accuracy of both methods. The study was carried out in vitro on thirty-two extracted teeth with calculus mounted in frasaco model. A total of 192 sites on six surfaces of the teeth bucally and lingually were recorded for the presence of subgingival calculus. Manual probing of calculus depended on tactile sensation and experience; where as electronic probing gave sound and light signal. The results showed that at the depth of 1-3mm, manual probing could detect 62.7% of calculus and electronic probing could detect more at 77.1%. At the deeper sites of 4-6mm, the ability for detection using electronic probing reduced to 14.1% with failure for detection at ≥ 7mm depth. However manual probing recorded more at 25% for 4-6mm calculus and 4.7% at ≥7mm. Manual and electronic probing has different sensitivity in detecting subgingival calculus with electronic probing being more sensitive at shallow sites and failed to detect calculus at deeper sites. It also has difficulty to differentiate between calculus and other roughness on tooth surfaces. These findings highlighted the accuracy and reliability of manual detection for deeper calculus. Redesigning calibration and length of electronic probe can improve its usage. Further study on clinical application to assess the impact of both probing may benefit clinical teaching of subgingival calculus detection and the outcome of periodontal patient’s management.