Ovate Pontic Versus Essix Provisional After Tooth Extraction and Alveolar Ridge Preservation (Pontic-Essix)

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.

• Bio-Oss Collagen (Device), also known as Fixed ovate pontic provisional, Removable Essix provisional with collagen matrix seal: 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.
• Mucograft Seal (Device): 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.
• Fixed 3D-printed ovate pontic provisional restoration (Procedure): 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.
• Removable Essix provisional restoration (Procedure): 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.

Primary outcomes

• Interproximal soft tissue height at 5 months [Baseline (T0) and 5 months after tooth extraction]: 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.

Secondary outcomes

• Midfacial mucosal level at 5 months [Baseline (T0) and 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.
• Horizontal ridge contour at 5 months [Baseline (T0) and 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.
• Mucosal thickness at 5 months [Baseline (T0) and 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
• Volumetric soft tissue at 5 months [Baseline (T0) and 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.
• Alveolar hard tissue volume at 5 months [Baseline (T0) and 5 months]: Volumetric measurement of alveolar hard tissue at 5 months (mm3), assessed on superimposed CBCT data. Baseline-adjusted analysis.
• Alveolar hard tissue contour at 5 months [Baseline (T0) and 5 months]: Linear measurement of alveolar hard tissue contour at 5 months (mm), assessed on superimposed CBCT data. Baseline-adjusted analysis.
• Postoperative discomfort (VAS) [2 weeks and 4 weeks after tooth extraction]: Postoperative discomfort assessed on a 100-mm visual analogue scale, ranging from 0 mm (no discomfort) to 100 mm (worst imaginable discomfort).
• Patient satisfaction with function (VAS) [5 months]: 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).
• Patient satisfaction with esthetics (VAS) [5 months]: 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).
• Patient satisfaction with comfort (VAS) [5 months]: 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).
• Overall treatment satisfaction (VAS) [5 months]: 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).
• Willingness to undergo the same procedure again (VAS) [5 months]: 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).
• Oral Health Impact Profile (OHIP-G14) [Baseline (T0) and 5 months]: 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.
• Geriatric Oral Health Assessment Index (GOHAI) [Baseline (T0) and 5 months]: 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.
• Adverse events and provisional-related complications [Up to 5 months]: 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.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Adults aged 18 years or older
* ASA physical status I or II
* Requiring a single non-molar tooth extraction (incisor, canine, or premolar) in the maxilla or mandible, with planned tooth replacement
* Extraction site bounded by natural, periodontally stable adjacent teeth
* Intact alveolar socket upon extraction, or no more than one bony wall (facial, palatal, or lingual) presenting a dehiscence extending less than 50% of the total bony wall height
* Willingness and ability to comply with the follow-up protocol
* Ability to give informed consent, as documented by signature

Exclusion Criteria:

* Current smokers, or former smokers who quit less than 6 months before extraction
* Uncontrolled diabetes mellitus (HbA1c > 7.0%)
* Clinical attachment loss ≥ 2 mm at the extraction site
* Active or recent chemotherapy, or history of head and neck radiotherapy
* Current or previous bisphosphonate therapy within the past 10 years
* Immunosuppressive medication
* Active oral or systemic acute infection
* Severe hematologic disorder, hepatic or renal failure, or any clinically relevant bleeding disorder or anticoagulant medication that cannot be safely managed for the planned surgical procedure
* Pregnancy or lactation
* Known allergy or hypersensitivity to any of the study materials, including bovine-derived bone substitute, porcine-derived collagen matrix, or collagen-containing biomaterials
* Any other disease or medication that may compromise normal wound healing
* Inability to follow the study procedures (e.g., insufficient language comprehension, cognitive impairment, psychological disorder, or dementia)
* Known or suspected non-compliance
* Participation in another clinical trial that may interfere with the present study

• Avila-Ortiz G, Gubler M, Romero-Bustillos M, Nicholas CL, Zimmerman MB, Barwacz CA. Efficacy of Alveolar Ridge Preservation: A Randomized Controlled Trial. J Dent Res. 2020 Apr;99(4):402-409. doi: 10.1177/0022034520905660. Epub 2020 Feb 12. PMID 32050833
• Couso-Queiruga E, Garaicoa-Pazmino C, Fonseca M, Chappuis V, Gonzalez-Martin O, Avila-Ortiz G. Interproximal Soft Tissue Height Changes After Unassisted Socket Healing vs Alveolar Ridge Preservation Therapy. Int J Periodontics Restorative Dent. 2024;44(5):520-533. doi: 10.11607/prd.6809. PMID 37471159

• Nicole Schenk, Dr. med. dent., Principal investigator, University of Bern, Department of Reconstructive Dentistry and Gerodontology
• Martin Schimmel, Prof. Dr. med. dent., Study chair, University of Bern, Department of Reconstructive Dentistry and Gerodontology
• Emilio Couso-Queiruga, PD Dr. med. dent., Study director, University of Bern, Department of Oral Surgery and Stomatology