CLINICAL COMPARISON OF DESIRED VERSUS ACTUAL AMOUNT OF SURGICAL CROWNLENGTHENING

THE ACTUAL LENGTH OF CLINICALLY EXPOSED tooth structure between planne d restoration margin and alveolar crest (''biologic width'') obtained during surgical crown elongation procedures was compared to the textbo ok goal of 3.0 mm. Sixteen (16) patients with 21 teeth requiring surgi cal crown lengthening for restoration placement participated. Oral hyg iene instructions were given and optimal plaque control was mandatory. At each clinician's discretion, surgical techniques consisted of eith er gingivectomy or an apically positioned flap with and without osseou s resection. Utilizing a reference stent, measurements were obtained a t the facial, mesial-facial, lingual, and distal-lingual of the treate d teeth both before and after osseous reduction. Parameters evaluated were gingival margin position, probing depth, mucogingival junction po sition, alveolar crest location, mobility, plaque index, and gingival index. These measurements were again recorded 8 weeks after surgery wi th the exception of alveolar crest. Statistical analysis with the pair ed t-test and linear correlation showed no significant change from bas eline or among operators with varying experience in any of these param eters. Overall the results showed that the default objective of 3 mm b etween planned restoration margin and alveolar crest was not routinely achieved (mean 2.4 +/- 1.4 mm). The post-treatment distance from the planned restoration margin to the alveolar crest was greatest at the f acial aspect of the teeth (mean 2.6 +/- 1.2 mm) and least at the dista l-lingual (mean 2.2 +/- 1.7 mm). In addition, although more experience d periodontists removed a larger amount of bone, the amount of root su rface exposed was still short of the initially desired biologic width. Within the limits of this clinical study a 3 mm biologic width was no t routinely achieved during surgical crown elongation.