The root coverage esthetic score: Intra-examiner reliability among dental students and dental faculty

The root coverage esthetic score (RES) was published in 2009 as an esthetic scoring system to measure visible final outcomes of root coverage procedures performed on Miller I and II recession defects. The aim of this study was to evaluate the intra-examiner, intra-group, and inter-examiner reliability of the RES when used among periodontal faculty, post-graduate students in periodontology, and pre-doctoral DMD students when using the RES at Tufts University School of Dental Medicine (TUSDM).

Thirty-three participants (12 second-year DMD students, 11 periodontal residents, and 10 faculty members) were assembled to evaluate 25 baseline and 6-month post-treatment outcomes of mucogingival surgeries using the RES. Each projection was shown for 30 seconds during which the participants were asked to use the RES scoring system to evaluate the surgical outcomes. The results were then recorded on a standardized worksheet grid. To test intra-examiner reliability, seven of the 25 projections were shown twice. Intra-examiner reliability and inter-examiner reliability were assessed using intraclass correlation coefficient using a two-way mixed effect model, and stratified by education level.

Post-graduate (PG) residents had the highest tendency to agree with each other with an interclass correlation (ICC) of 0.53 (95% confidence interval [CI] 0.36 to 0.74). DMD students had an ICC: 0.51 (95% CI: 0.33 to 0.75), and PG faculty members produced an ICC: 0.41 (95% CI: 0.24 to 0.64). There was no statistically significant difference in ICC among the three groups of participants (Kruskal-Wallis test, P = 0.2440). When the data for each RES element were then combined, the mean ICC for the total inter-rater agreement for RES was 0.48 (95% CI: 0.32 to 0.71). This corresponds to an overall moderate agreement among all participants using the RES to evaluate the 25 surgical outcomes. The intra-examiner reliability within each of the three groups was quite high. The highest mean ICC was produced by PG faculty (0.908). The mean ICCs for PG residents was 0.867, and the mean ICC for DMD students was 0.855. The Kruskal-Wallis test (P = 0.46) failed to find any statistical difference in intra-examiner reliability among the three groups of participants.

The RES is a "moderately" reliable scoring system for mucogingival treatments in a dental school setting and can be used even by operators with different levels of periodontal experience. This scoring system can be repeated by the same examiner to obtain reliable results.