Esthetic Crown Lengthening With Closed Piezoelectric in Comparison to Open Flap Approach

In this randomized clinical trial, the investigators are comparing two different approaches for Esthetic crown lengthening- a minimally invasive approach using piezoelectric (PZ) and a traditional open flap approach (OF).

The altered passive eruption is diagnosed when there is an excessive gingival display with short clinical crowns. Esthetic crown lengthening (ECL) is the most common surgical treatment of altered passive eruption. Traditional ECL involves osseous resection with gingivectomy or apical displaced gingiva. The amount of soft and hard tissue removal in this technique aims to provide a healthy and esthetically acceptable crown height. However, gingival tissue coronal rebound is one of the most noted post-operative complications of traditionally used techniques. On the other hand, surgical techniques that include flap reflection may cause more coronal displacement of the gingival margin. Hence, it is crucial to assess different surgical techniques to determine the most effective technique that gives the required outcomes with maximum patient satisfaction. Piezoelectric bone surgery delivers high precision in resection, good tactile sensibility, and permits a selective cut of mineralized tissue while sparing soft tissue. Further, the minimally invasive technique (mECL) was suggested to reduce pain, post-op discomfort, and procedure duration, and to accelerate the healing process. The mECL technique conveys a potential alternative approach as a sutureless, atraumatic, and less invasive technique that has been shown to increase patient satisfaction and comfort. In addition, using piezoelectric for osseous resection in this closed approach increases the favorable surgical outcomes. However, the osseous resection in mECL may be incomplete and results in a coronal rebound on the gingival contour. In addition, osseous resection in this approach is very technique sensitive to avoid root damage and uneven bone resection. A few studies and even a fewer clinical trials evaluated the clinical outcome of mECL using piezoelectric for osseous resection (PZ). Hence, in this randomized clinical trial, gingival margin and bone crest stability will be evaluated after a minimally invasive approach using piezoelectric (PZ) and a traditional open flap approach (OF).

Subjects' matching inclusion criteria will be randomly assigned to control (OF) or tested (PZ) groups. After eligibility has been ascertained and consent has been obtained, subjects planned for ECL will be enrolled in the study and assigned to the group in 1:1 ratio using computer-generated block randomization scheme.

Flapless Technique using Piezoelectric (PZ): Gingivectomy and intra-sulcular incision will be carried out to remove strip of outlined marginal gingiva. However, no flap will be reflected the osseous recontouring will be carried using special piezoelectric tip below gingival margin. The required distance between the bone crest and the gingival margin will be checked by inserting a periodontal probe into the incision below gingival margin.

Open Flap Technique (OF): Gingivectomy and intra-sulcular incision will be carried out to remove strip of outlined marginal gingiva. Full mucoperiosteal flap will be elevated to preform ostectomy and/or osteoplasty until the desired distance achieved between the bone crest and the gingival margin. After achieving the new supracrestal distance, the flap will be sutured.

Inclusion Criteria: Patients with a gummy smile due to APE (Type 1B) in two or more maxillary anterior teeth Patients with normal muscular efficiency of the upper lip Patients with no vertical skeletal defects Exclusion Criteria: Patients with systemic condition that prevent periodontal surgery Patients who smoke Patients with previous periodontal surgery in the same area Pregnant women