Investigating the utility of 3D-intraoral scan imaging to score plaque compared to visual clinical assessment

To determine the diagnostic accuracy between intraoral scan-derived plaque assessment (IOS) compared with clinical plaque assessment as the reference standard, before and after plaque disclosure.

Single-site, cross-sectional study. Eligible participants were adults with a minimum of 20 natural teeth. Following IOS, undisclosed plaque was assessed clinically on all scorable teeth at four sites per tooth using Silness and Löe plaque index. Disclosing agent was applied and plaque scoring repeated, followed by a second IOS. After a wash-out period, the clinical examiner assessed plaque scores on-scan, a second examiner also assessed plaque scores on-scan.

60 participants aged 19-74 were recruited. Agreement between clinical pre- and post-disclosure scores was poor, with a large increase in plaque detected following use of disclosing agent. Compared to clinical assessment, IOS plaque assessment demonstrated high sensitivity pre- and post-disclosure (90.4, 96.1% and 91.0, 93.9% respectively), while specificity was lower, particularly for undisclosed plaque (30.3, 44.9%), which improved post-disclosure (49.2, 55.9%). When pre-disclosure scores were compared to post-disclosure scores on-scan, sensitivity remained high (80.8, 86.4%), while specificity was lower (38.4, 63.8%). Intra-examiner agreement was higher than inter-examiner agreement, with both increasing following plaque disclosure: intra-examiner agreement increased from 87.5% to 91.5%, and inter-examiner agreement increased from 79.7% to 85.7%. Overall, IOS-derived plaque assessment identified a greater proportion of plaque-positive sites than clinical assessment, with the degree of overestimation reducing following plaque disclosure (29.4% pre disclosure; 14.1% post-disclosure).

IOS-derived plaque assessment demonstrated high diagnostic sensitivity for detecting plaque both pre- and post-disclosure. However, lower specificity indicates a tendency to overestimate the presence of plaque, although diagnostic performance improved following plaque disclosure.

IOS-derived plaque assessment demonstrates good diagnostic capability for plaque detection and offers potential clinical advantages over conventional visual assessment by enabling the capture and review of plaque assessment at subsequent visits. IOS may therefore represent a promising tool for plaque assessment in clinical dental practice.