Collagen Matrix + rhPDGF-BB vs Connective Tissue Graft for the Treatment of Peri-implant Soft Tissue Dehiscences

Study Overview
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Brief Summary
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The study aims at comparing two different approaches for the treatment of implant esthetic complications (peri-implant soft tissue dehiscences): autogenous connective tissue graft vs collagen matrix + recombinant human platelet derived growth factor-BB

Detailed Description
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The present randomized clinical trial aims at investigating two approaches (autogenous connective tissue graft vs collagen matrix + recombinant human platelet derived growth factor-BB) when performed in combination with the prosthetic-surgical approach for the treatment of peri-implant soft tissue dehiscences. Clinical, volumetric, ultrasonographic and patient-reported outcomes will be evaluated at different time points up to 1 year.

Official Title
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Xenogeneic Collagen Matrix Loaded With rhPDGF-BB vs Autogenous Connective Tissue Graft for the Treatment of Peri-implant Soft Tissue Dehiscences: A Randomized, Controlled, Clinical, Trial

Conditions
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Implant Complication

Intervention / Treatment
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* Other: Prosthetic-surgical approach + autogenous graft
* Other: Prosthetic-surgical approach + graft substitute


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years, Periodontally and systemically healthy, Full-mouth plaque score and full-mouth bleeding score ≤ 20% (measured at four sites per tooth), iv) Presence of single dental implant in the anterior area (from the first right premolar to the first left premolar) showing a PSTD, with the subjects searching for treatment of this condition, Peri-implant papillae not flat (PSTD subclass a or b) (Zucchelli et al., 2019), vi) Implants diagnosed as healthy (Berglundh et al., 2018), Ability to perform good oral hygiene Exclusion Criteria: Contraindications for surgery, Systemic condition (e.g. diabetes mellitus, HIV, cancer, etc) that could compromise wound healing, Patients pregnant or attempting to get pregnant (self-reported), Untreated periodontitis, Untreated peri-implant mucositis or peri-implantitis (Berglundh et al., 2018), Smoking, defined as self-reported daily habit. Occasional smokers won't be excluded, History of soft tissue grafting at the implant site showing PSTD within the last 6 months. Indications for surgical intervention will be established based on patient's esthetic demands and peri-implant soft tissue phenotype.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Parallel-arm
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Connective tissue graft<br>Autogenous connective tissue graft harvested from the palate as a free gingival graft and then de-epithelialized | Other: Prosthetic-surgical approach + autogenous graft<br>* Coronally advanced flap with an autogenous graft (CTG)<br>|
| Experimental: Collagen matrix + rhPDGF-BB<br>Xenogeneic cross-linked collagen matrix + recombinant human platelet-derived growth factor-BB | Other: Prosthetic-surgical approach + graft substitute<br>* Coronally advanced flap with a graft substitute (collagen matrix and rhPDGF-BB)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Soft tissue dehiscence reduction | Reduction of the depth of the Soft tissue dehiscence (vertical measurement of the complication, in relation to the level of the cemento-enamel junction of the contralateral homologous tooth) compared to baseline (expressed in millimeters) | 6 and 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Complete peri-implant soft tissue dehiscence (PSTD) coverage | Percentage of cases with complete resolution of the implant esthetic complication (expressed as a percentage) | 6 and 12 months | 
| mean peri-implant soft tissue dehiscence (PSTD) coverage | Percentage of coverage of the soft tissue dehiscence compared to baseline, measured with a formula considering final PSTD depth and initial PSTD depth (expressed as a percentage) | 6 and 12 months | 
| Mucosal thickness changes | Changes within the mucosal thickness measured with ultrasonography (expressed in mm) | 3, 6 and 12 months | 
| 3D Volumetric changes | Changes within the buccal contour measured by superimposing digital impressions obtained with optical scanning (expressed in mm^3) | 3, 6 and 12 months | 
| Post-operative pain | Patient-reported pain after the surgical procedure (expressed with a 0-10 visual analogue scale [VAS]) | 14 days after the surgery | 
| Professional esthetic assessment | Esthetic outcomes of the treatment assessed by a calibrated operator using the Implant soft tissue Dehiscence coverage Esthetic Score (IDES) (expressed using points, based on the IDES classification system from Zucchelli et al. 2021) | 12 months |