Evaluation of minimally invasive esthetic crown lengthening using an open flap versus flapless surgical approach: A randomized controlled clinical trial

Objectives

Esthetic crown lengthening (ECL) is commonly advocated to treat patients with altered passive eruption (APE). Since the introduction of the minimally invasive surgical concept, a limited number of studies have investigated this technique in a standardized manner, with further studies required to verify the validity and predictability of the minimally invasive FL-technique. The current randomized trial compares a minimally invasive (ECL), using piezosurgery with flapless-approach (FL), versus an open-flap (OF) approach in the management of patients with APE Type 1B.

Materials and Methods

Twenty-four patients diagnosed with APE Type 1B were randomly assigned into test (FL) with tunneling approach or control (OF) group with minimally invasive flap reflection (n = 12/group). Postoperative pain was assessed during the first 48 h. Gingival margin (GM) level relative to a custom-made stent (rGM) and patient satisfaction were assessed preoperative, immediately after surgery, at 3 and 6 months postsurgically. Postoperative swelling was reported for the first week postsurgically. Plaque index (PI), bleeding on probing (BoP), clinical attachment level (CAL), pocket depth (PD) and pink esthetic score (PES), were evaluated at baseline and 6 months. Linear regression analysis was conducted for pain.

Results

OF-group reported significantly higher pain and swelling scores than FL-group during the first 48 h (p < 0.05). FL-group showed no significant differences regarding rGM between 3 and 6 months, in contrast to OF-group, where a significant decrease in rGM was notable (p < 0.05). No significant differences in PI, BoP, CAL, PD, PES, and patient satisfaction scores were evident between groups (p > 0.05). Regression analysis demonstrated that treatment and gender were significant predictors for pain (p < 0.05).

Conclusions

Within the current study's limitations, piezo-surgical ECL with FL-approach presented significantly lower postoperative pain, swelling, and early GM stability compared to OF-approach.

Clinical Significance

Piezosurgical ECL with a FL-approach can be considered a predictable technique with advantages over the OF-approach in the management of patients with APE Type1B.