This randomized controlled trial compares two provisional socket-sealing concepts following single non-molar tooth extraction and alveolar ridge preservation: a fixed, tooth-supported, 3D-printed ovate pontic provisional restoration providing active soft tissue support (test) versus a removable Essix-type provisional restoration without intentional soft tissue contact combined with a porcine collagen matrix seal (control). Both groups receive alveolar ridge preservation using a deproteinized bovine bone mineral with 10% collagen. The primary endpoint is interproximal soft tissue height at 5 months, adjusted for baseline, assessed by digital superimposition of intraoral surface scans. Up to 40 participants will be enrolled at the University of Bern School of Dental Medicine.
Following tooth extraction, dimensional changes of the alveolar ridge and loss of interproximal soft tissue height may compromise esthetic and prosthetic outcomes. Alveolar ridge preservation attenuates hard tissue resorption but provides limited active support for the overlying soft tissues during healing. An ovate pontic provisional restoration may provide active soft tissue support and thereby help preserve interproximal soft tissue height. To date, no randomized controlled trial has compared a fixed ovate pontic provisional restoration with a removable non-contact Essix provisional restoration in the context of alveolar ridge preservation. This is a single-center, open-label, confirmatory, randomized controlled trial with two parallel groups and 1:1 allocation. An adaptive design with an internal pilot phase (n=20) and blinded sample size re-estimation based on the residual variance of the primary endpoint is applied, up to a predefined maximum of 40 participants. All participants undergo minimally traumatic, flapless single non-molar tooth extraction and alveolar ridge preservation with Bio-Oss Collagen. Test group: socket sealing by a fixed, 3D-printed ovate pontic provisional restoration providing active soft tissue support. Control group: socket sealing with Mucograft Seal plus a removable Essix-type provisional restoration positioned without intentional soft tissue contact. Follow-up visits are performed at 2 weeks, 4 weeks, and 5 months. At baseline (T0) and at 5 months, intraoral surface scans, clinical photographs, cone-beam computed tomography, and patient-reported outcomes are collected. The between-group treatment effect on the primary endpoint is estimated using ANCOVA with the 5-month value as dependent variable, treatment group as fixed factor, and the baseline value as covariate; jaw is included as an additional between-subject factor.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
40
Deproteinized bovine bone mineral with 10% collagen (Geistlich Pharma AG, Wolhusen, Switzerland). Used for alveolar ridge preservation by socket grafting after tooth extraction. CE-marked and used within the approved indication.
Patient-specific 3D-printed provisional restoration (PMMA or comparable clinically approved dental provisional material) incorporating an ovate pontic design. Retained by adhesive bonding or temporary cementation on the adjacent teeth. The convex, highly polished pontic extends approximately 2 mm apical to the mucosal margin and above the level of the bone graft, providing active soft tissue support.
Patient-specific 3D-printed provisional restoration (PMMA or comparable clinically approved dental provisional material) incorporating an ovate pontic design. Retained by adhesive bonding or temporary cementation on the adjacent teeth. The convex, highly polished pontic extends approximately 2 mm apical to the mucosal margin and above the level of the bone graft, providing active soft tissue support.
Patient-specific removable thermoplastic Essix-type appliance with an integrated artificial tooth. The pontic is positioned above the mucosal level without intentional soft tissue contact. Delivered at the surgical visit after socket sealing with the collagen matrix.
University of Bern, Department of Reconstructive Dentistry and Gerodontology
Bern, Canton of Bern, Switzerland
Interproximal soft tissue height at 5 months
Interproximal soft tissue height at 5 months, calculated per participant as the mean of the mesial and distal measurements and expressed in millimeters. Measurements are obtained by digital superimposition of baseline and 5-month intraoral surface scans (Geomagic Control X, 3D Systems) by an independent, calibrated examiner. The between-group treatment effect is estimated using ANCOVA with the 5-month value as the dependent variable, treatment group as a fixed factor, baseline value as a covariate, and jaw as an additional between-subject factor.
Time frame: Baseline (T0) and 5 months after tooth extraction
Midfacial mucosal level at 5 months
Vertical position of the midfacial mucosal margin at 5 months (mm), assessed on superimposed intraoral surface scans. The between-group difference is estimated using ANCOVA with the 5-month value as dependent variable and the baseline value as covariate.
Time frame: Baseline (T0) and 5 months
Horizontal ridge contour at 5 months
Horizontal ridge contour at 5 months (mm) at 1, 3, and 5 mm apical to the baseline mucosal reference, assessed on superimposed intraoral surface scans. Baseline-adjusted analysis at each level.
Time frame: Baseline (T0) and 5 months
Mucosal thickness at 5 months
Mucosal thickness at 5 months (mm) at 1, 3, and 5 mm apical to the baseline mucosal reference. Baseline-adjusted analysis at each level
Time frame: Baseline (T0) and 5 months
Volumetric soft tissue at 5 months
Volumetric soft tissue measurement at 5 months (mm3) within the defined region of interest, assessed on superimposed intraoral surface scans. Baseline-adjusted analysis.
Time frame: Baseline (T0) and 5 months
Alveolar hard tissue volume at 5 months
Volumetric measurement of alveolar hard tissue at 5 months (mm3), assessed on superimposed CBCT data. Baseline-adjusted analysis.
Time frame: Baseline (T0) and 5 months
Alveolar hard tissue contour at 5 months
Linear measurement of alveolar hard tissue contour at 5 months (mm), assessed on superimposed CBCT data. Baseline-adjusted analysis.
Time frame: Baseline (T0) and 5 months
Postoperative discomfort (VAS)
Postoperative discomfort assessed on a 100-mm visual analogue scale, ranging from 0 mm (no discomfort) to 100 mm (worst imaginable discomfort).
Time frame: 2 weeks and 4 weeks after tooth extraction
Patient satisfaction with function (VAS)
Patient-rated satisfaction with the function of the provisional restoration, assessed on a 100-mm visual analogue scale, ranging from 0 mm (completely unsatisfied) to 100 mm (completely satisfied).
Time frame: 5 months
Patient satisfaction with esthetics (VAS)
Patient-rated satisfaction with the esthetics of the provisional restoration, assessed on a 100-mm visual analogue scale, ranging from 0 mm (completely unsatisfied) to 100 mm (completely satisfied).
Time frame: 5 months
Patient satisfaction with comfort (VAS)
Patient-rated satisfaction with the comfort of the provisional restoration, assessed on a 100-mm visual analogue scale, ranging from 0 mm (completely unsatisfied) to 100 mm (completely satisfied).
Time frame: 5 months
Overall treatment satisfaction (VAS)
Patient-rated overall satisfaction with the treatment received, assessed on a 100-mm visual analogue scale, ranging from 0 mm (completely unsatisfied) to 100 mm (completely satisfied).
Time frame: 5 months
Willingness to undergo the same procedure again (VAS)
Patient-rated willingness to undergo the same procedure again, assessed on a 100-mm visual analogue scale, ranging from 0 mm (definitely not) to 100 mm (definitely yes).
Time frame: 5 months
Oral Health Impact Profile (OHIP-G14)
German version of the Oral Health Impact Profile, 14-item version. Summary score range 0 to 56; higher scores indicate worse oral health-related quality of life.
Time frame: Baseline (T0) and 5 months
Geriatric Oral Health Assessment Index (GOHAI)
German version of the Geriatric Oral Health Assessment Index. Summary score range 12 to 60; higher scores indicate better oral health-related quality of life.
Time frame: Baseline (T0) and 5 months
Adverse events and provisional-related complications
Occurrence and rate of adverse events, including postoperative infection, impaired wound healing, soft tissue dehiscence, loss or displacement of the bone substitute or collagen matrix, allergic or hypersensitivity reactions, pressure-induced mucosal lesions, debonding of the fixed provisional restoration, or irritation related to the Essix provisional.
Time frame: Up to 5 months
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