Open-flap Versus Flapless Esthetic Crown Lengthening: 12-month Clinical Outcomes of a Randomized Controlled Clinical Trial

Experimental design and treatment protocols

In this prospective, split-mouth, randomized controlled clinical study, 28 subjects (21 - 40 years old) requiring correction of EGD will received ECL using OF and FL techniques. A computer-generated table randomly distributed the right quadrant to receive OF or FL techniques. Consequently, the contralateral left quadrant was allocated to the other group. The following treatments were performed:

OF (control group; n=28 sides/105 teeth): An internal beveled incision was performed at the buccal aspect of the involved teeth. Afterwards, a sulcular incision was completed to allow gingival tissue removal. A full-thickness mucoperiosteal flap was reflected to remove and remodel bone tissue by means of surgical chisels, as necessary, until a 3mm distance was achieved between the bone crest and the cement-enamel junction (CEJ). The exposed root surfaces were carefully planed with curettes. Interrupted sutures were performed at the papilla to allow GM stabilization in the CEJ position.

FL (test group; n=28 sides/105 teeth): Internal beveled and sulcular incisions and gingival tissue removal were performed as above described for the control group, replacing the GM in the CEJ position. However, the alveolar bone was removed and remodeled, as necessary, using micro chisels, via incisions, without flap elevation. The root surfaces were also carefully planed via incisions. The required distance of 3mm between the bone crest and the CEJ was checked by inserting a periodontal probe into the incision. Sutures were not performed.

After both procedures, canines and central incisors should be at the same length, and the lateral incisor should be 1mm shorter. The same periodontist (F.R.V.) performed all surgeries. Chlorhexidine gluconate mouthwash (0.12%) was prescribed 2x/day for 2 weeks. Analgesics were prescribed to control possible postoperative discomfort. The sutures of control quadrants were removed after 7 days. The surgical time for test and control, starting after anesthesia, was computed.