Clinical evaluation of the supraosseous gingivae before and after crown lengthening

Background: Despite the broad use of crown-lengthening surgery (CLS), there is no complete agreement as to the desired amount of exposed sound tooth structure needed to accommodate both the restorative needs and the reformation of the supraosseous gingiva (SOG). Classically, it has been proposed that ∼3 mm of SOG, the amount considered by most to be present before surgery, will be reformed after CLS. The purpose of this study was to test the viability of transsulcular probing (TSP) and to determine whether the SOG that forms after CLS is the same as that measured preoperatively. Methods: Nineteen patients underwent CLS with the surgical tooth acting both as the control and the test site. The SOG dimension was measured by TSP before and 6 months after surgery. Stents were used as fixed reference points. Intraclass correlations were calculated to test for the reliability of TSP measurements versus direct-bone-level (DBL) measurements. A Wilcoxon signed-rank test was used to compare the means for the mean buccal, mean lingual, and overall mean SOG dimensions at baseline to corresponding measurements at 6 months. Results: Intraclass correlation coefficients for TSP measures of SOG to DBL measures of SOG ranged from 83.4% agreement to 91.9% agreement, with all correlations being highly significant (P