One- Versus Two-Stage Aesthetic Crown Lengthening

One- Versus Two-Stage Aesthetic Crown Lengthening for Restorative Purposes: A Randomized Controlled Trial.

This randomized controlled trial was aimed at assessing the efficacy of a two-stage crown lengthening intervention (SCL) for restorative purposes in the aesthetic zone compared with a one-stage crown lengthening procedure (CCL).

Study Overview

• Status: Completed
• Conditions: Patients in Need of Surgical CL in the Anterior Maxillary Sextant for Restorative Purposes
• Intervention / Treatment: Other: Conventional Crown Lengthening (CCL); Other: Two-stage Crown Lengthening (SCL)

Detailed Description

Subjects were randomly allocated to receive SCL or CCL. SCL consisted of full thickness flaps followed by bone recontouring and minor gingivectomy 4 months postoperatively, if required. In CCL, osseous recontouring after sub-marginal incisions was performed, followed by flap repositioning. Records were obtained at baseline, 4 months (only in SCL), 6 and 12 months. Primary outcome was the precision in achieving a predetermined gingival margin position. Other outcomes were changes in the gingival margin position and keratinized tissue width (KTW) at 12 months, and patient-reported outcomes (PROMs) using the OHIP-14 tool.

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• older than eighteen years of age;
• more than 20 teeth in the mouth;
• with full mouth plaque and bleeding scores lower than 15%; and
• without probing pocket depth and/or attachment loss >4 mm

Exclusion Criteria:

• Pregnant women or breastfeeding
• smokers
• treated with antimicrobial and/or anti-inflammatory drugs within two months prior to entering the study
• currently undergoing orthodontic therapy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Conventional Crown Lengthening; CCL; Using the surgical guide, submarginal internal bevel incisions were performed on the buccal aspect of the affected teeth. A full-thickness flap was raised up to the mucogingival junction (Dominguez et al., 2020). Ostectomy and osteoplasty were carried out by means of rotatory instruments and surgical chisels, as necessary, to achieve the necessary space between the bone crest and the restorative margin according to the presurgical plan. The CEJ was not the reference point since, in many cases, the position of the final margin of the restoration was planned apical to the actual position of the CEJ. Exposed root surfaces were carefully instrumented manually with curettes and, finally, vertical internal mattress sutures were placed to position the gingival margin at the level of the margin of the planned restoration. Sutures were removed after 7 days.	Other: Conventional Crown Lengthening (CCL); Using the surgical guide, submarginal internal bevel incisions were performed on the buccal aspect of the affected teeth. A full-thickness flap was raised up to the mucogingival junction (Dominguez et al., 2020). Ostectomy and osteoplasty were carried out by means of rotatory instruments and surgical chisels, as necessary, to achieve the necessary space between the bone crest and the restorative margin according to the presurgical plan. The CEJ was not the reference point since, in many cases, the position of the final margin of the restoration was planned apical to the actual position of the CEJ. Exposed root surfaces were carefully instrumented manually with curettes and, finally, vertical internal mattress sutures were placed to position the gingival margin at the level of the margin of the planned restoration. Sutures were removed after 7 days
Experimental: Two-stage Crown Lengthening (SCL); In the first surgical intervention, intrasulcular incisions were performed and a full thickness flap was raised up to the mucogingival junction. Ostectomy and osteoplasty were performed to establish the space for supracrestal tissue attachment, following the restorative plan and using the presurgical blueprint as the reference to determine the final position of the restoration margin, instead of the CEJ (Lee, 2004). Then the flaps were repositioned and secured with internal mattress sutures, placing the gingival margin at the original level. Sutures were removed at 7 days. In the second stage, after 3-4 months, minor gingival recontouring was performed, if necessary, to attain the desired gingival margin position according to the presurgical plan	Other: Two-stage Crown Lengthening (SCL); In the first surgical intervention, intrasulcular incisions were performed and a full thickness flap was raised up to the mucogingival junction. Ostectomy and osteoplasty were performed to establish the space for supracrestal tissue attachment, following the restorative plan and using the presurgical blueprint as the reference to determine the final position of the restoration margin, instead of the CEJ (Lee, 2004). Then the flaps were repositioned and secured with internal mattress sutures, placing the gingival margin at the original level. Sutures were removed at 7 days. In the second stage, after 3-4 months, minor gingival recontouring was performed, if necessary, to attain the desired gingival margin position according to the presurgical plan.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
T1-T4	The difference in mm between the ideal gingival margin (T1) and the position of the gingival margin at 12 months (T4).	Baseline-12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinical Crown Length	Distance from the gingival margin to the incisal edge on the midbuccal.Measured in mm.	At baseline, 6- and 12-month
Amount of keratinized tissue	Distance from the gingival margin to the mucogingival junction on the midbuccal.Measured in mm.	At baseline, 6- and 12-month
Gingival display upon smiling	Distance from the gingival margin of the central incisors to the lower edge of the upper lip. Measured in mm.	At baseline, 6- and 12-month
Supracrestal tissue dimension	Distance from the gingival margin to the alveolar bone crest (GM-ABC) as determined by bone sounding following local anesthesia. Measured in mm.	At baseline, 6- and 12-month

Collaborators and Investigators

• Sponsor: Universidad Complutense de Madrid

Publications and helpful links

General Publications

• Gonzalez-Martin O, Carbajo G, Rodrigo M, Montero E, Sanz M. One- versus two-stage crown lengthening surgical procedure for aesthetic restorative purposes: A randomized controlled trial. J Clin Periodontol. 2020 Dec;47(12):1511-1521. doi: 10.1111/jcpe.13375. Epub 2020 Oct 20.

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2013
• Primary Completion (Actual): October 1, 2018
• Study Completion (Actual): October 1, 2018

Study Registration Dates

• First Submitted: May 26, 2020
• First Submitted That Met QC Criteria: May 26, 2020
• First Posted (Actual): June 1, 2020

Study Record Updates

• Last Update Posted (Actual): June 1, 2020
• Last Update Submitted That Met QC Criteria: May 26, 2020
• Last Verified: May 1, 2020

More Information

Terms related to this study

• Other Study ID Numbers: Crown Lengthening RCT

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No