Resumen de Open-Flap Versus Flapless Esthetic Crown Lengthening: 12-Month Clinical Outcomes of a Randomized Controlled Clinical Trial
Background: Excessive gingival display (EGD) has a negative impact on a pleasant smile. Minimally invasive therapeutic modalities have become the standard treatment in many dentistry fields. Therefore, the aim of this study is to compare the clinical outcomes of open-flap (OF) and minimally invasive flapless (FL) esthetic crown lengthening (ECL) for the treatment of EGD.
Methods: A split-mouth randomized controlled trial was conducted in 28 patients presenting with EGD. Contralateral quadrants received ECL using OF or FL techniques. Clinical parameters were evaluated at baseline and 3, 6, and 12 months post-surgery. The local levels of receptor activator of nuclear factor-?B ligand (RANKL) and osteoprotegerin (OPG) were assessed by enzyme-linked immunosorbent assay at baseline and 3 months. Patients� perceptions regarding morbidity and esthetic appearance were also evaluated. Periodontal tissue dimensions were obtained by computed tomography at baseline and correlated with the changes in the gingival margin (GM).
Results: Patients reported low morbidity and high satisfaction with esthetic appearance for both procedures (P >0.05). RANKL and OPG concentrations were increased in the OF group at 3 months (P <0.05). Probing depths were reduced for both groups at all time points, compared with baseline (P <0.05). There were no differences between groups for GM reduction at any time point (P >0.05).
Conclusions: FL and OF surgeries produced stable and similar clinical results up to 12 months. FL ECL may be a predictable alternative approach for the treatment of EGD.
Excessive gingival display (EGD) or a �gummy smile� presents a negative impact on esthetic appearance.1,2 It is caused by the hyperactivity of the elevator muscle of the upper lip, vertical overgrowth of the maxilla, gingival enlargement, and/or altered passive eruption. Altered passive eruption is a clinical condition in which the gingival margin (GM) is positioned coronally on the anatomic crown due to disorders in the eruptive patterns of the dentogingival unit, resulting in short clinical crowns.3,4 The management of EGD may involve a variety of treatment modalities, depending on its specific etiology.2,4,5 If the EGD is related to altered passive eruption or gingival enlargement, it can be effectively corrected by periodontal surgeries.4 Crown-lengthening techniques, including the apically positioned flap and gingivectomy with bone recontouring as necessary, can improve EGD and uneven gingival contour due to delayed passive eruption.6,7 These surgical procedures must be able to reduce the excessive gingival tissue, expose the desirable clinical crowns, and reestablish the appropriate biologic width.6,7 Surprisingly, although the surgical management of EGD has been presented by several case reports and case series,4,8-10 to date, no controlled clinical study has compared surgical techniques for esthetic crown lengthening (ECL).
Traditional ECL procedures generally involve elevation of a full-thickness flap to access and recontour the bone crest to preserve the biologic width.7 These methods are often time-consuming, require sutures, and may cause postoperative morbidity for the patient. Reducing the undesirable outcomes of conventional surgeries and increasing patient acceptance require less-invasive techniques that are able to achieve better or similar results with less morbidity compared with traditional surgeries. Because minimally invasive therapeutic modalities have become the standard of care in many medical and dentistry fields, this study evaluates a minimally invasive surgical technique for ECL.11 This technique is a modification of the conventional surgery in which the gingival and bone tissues are remodeled without flap elevation. Therefore, this study aims to compare the clinical outcomes of the conventional open-flap (OF) and the minimally invasive flapless (FL) ECL for the treatment of EGD up to 12 months. It is hypothesized that the FL surgery would yield similar clinical results to the OF technique up to 12 months.
