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

Official title

Socket Sealing With a Fixed Ovate Pontic Provisional Versus a Removable Provisional Following Tooth Extraction and Alveolar Ridge Preservation: A Randomized Controlled Trial

Overview

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.

Detailed description

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.

Interventions

• Device Bio-Oss Collagen
  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.
• Device Mucograft Seal
  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.
• Procedure Fixed 3D-printed ovate pontic provisional restoration
  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.
• Procedure Removable Essix provisional restoration
  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 outcome measures

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

Secondary outcome measures (12)

• Midfacial mucosal level at 5 months [Time frame: Baseline (T0) and 5 months]
• Horizontal ridge contour at 5 months [Time frame: Baseline (T0) and 5 months]
• Mucosal thickness at 5 months [Time frame: Baseline (T0) and 5 months]
• Volumetric soft tissue at 5 months [Time frame: Baseline (T0) and 5 months]
• Alveolar hard tissue volume at 5 months [Time frame: Baseline (T0) and 5 months]
• Alveolar hard tissue contour at 5 months [Time frame: Baseline (T0) and 5 months]
• Postoperative discomfort (VAS) [Time frame: 2 weeks and 4 weeks after tooth extraction]
• Patient satisfaction with function (VAS) [Time frame: 5 months]
• Patient satisfaction with esthetics (VAS) [Time frame: 5 months]
• Patient satisfaction with comfort (VAS) [Time frame: 5 months]
• Overall treatment satisfaction (VAS) [Time frame: 5 months]
• Willingness to undergo the same procedure again (VAS) [Time frame: 5 months]

Eligibility criteria

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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

Switzerland · 1 center

• University of Bern, Department of Reconstructive Dentistry and Gerodontology — Bern

Publications

• 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

Identifiers

NCT: NCT07748871 · Pontic-Essix · 2026-01626

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗