Buccal Graft + Collagen Matrix Versus Free Gingival Graft for Keratinized Mucosa Augmentation at Implant Sites

Study Overview
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Brief Summary
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The study aims at comparing two different approaches for soft tissue augmentation at implants lacking keratinized and adherent mucosa width: the free gingival graft (FGG) vs the Buccal Strip Graft in combination with a xenogeneic collagen matrix (BSG + CM)

Detailed Description
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Conventional free gingival graft (FGG), serving as control group, will be compared to buccal strip gingival graft (BSG) in combination with a collagen matrix (CM), serving as test group, in terms of clinical, volumetric, ultrasonographic, and patient-reported outcomes related to soft tissue augmentation at implant sites lacking keratinized and adherent mucosa.

Official Title
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Buccal Strip Gingival Graft With a Xenogeneic Collagen Matrix Versus Free Gingival Graft for Keratinized Mucosa Augmentation at Implant Sites: A Randomized, Controlled, Clinical Trial

Conditions
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Surgery

Intervention / Treatment
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* Procedure: Conventional Free Gingival Graft Approach (FGG)
* Procedure: Buccal Strip Graft with a collagen matrix (bSG + CM)


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 ≤ 20% (measured at four sites per tooth), Presence of at least one dental implant with < 2 mm of KM and lack of firm/adherent mucosa, Presence of at least 4 mm of keratinized gingiva in two or more teeth nonadjacent to the implant to be treated, Implants diagnosed as healthy (Berglundh et al. 2018), The patient must be able 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, Allergy to collagen-based medical products or iodine, Previous free gingival graft procedure at the target site.

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
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Free gingival graft (FGG)<br>Conventional free gingival graft, involving the harvesting of an epithelialized graft from the hard palate, which is then stabilized/sutured to the recipient site (implant). | Procedure: Conventional Free Gingival Graft Approach (FGG)<br>* Conventional Free Gingival Graft Approach involving palatal soft tissue harvesting<br>|
| Experimental: Buccal Strip Graft + Collagen matrix (bSG + CM)<br>Strip graft obtained from the buccal mucosa of a site showing abundant keratinized gingiva, combined with a collagen matrix. The bSG + CM graft is stabilized/sutured to the recipient site (implant). | Procedure: Buccal Strip Graft with a collagen matrix (bSG + CM)<br>* A small strip of keratinized gingiva is harvested from the buccal gingiva of a site showing abundant keratinized gingiva, and combined with a xenogeneic collagen matrix<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sites showing KM≥ 2 mm and AM≥ 1 mm | Number of sites showing at least 2 mm of keratinized mucosa width (in millimeters) and at least of 1 mm of attached mucosa (in millimeters) (outcome expressed as a number) | 6 and 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| KM width gain | Gain in keratinized mucosa width obtained after the intervention compared to baseline (expressed in millimeters) | 6 and 12 months | 
| AM gain | Gain in attached mucosa width obtained after the intervention compared to baseline (expressed in millimeters) | 6 and 12 months | 
| Mucosal thickness (MT) gain | Gain of mucosal thickness (MT) obtained after the intervention compared to baseline (expressed in millimeters) | 6 and 12 months | 
| Volumetric change | Volumetric change occurring at the treated sites analyzed by superimposing digital impressions obtained using optical scanners at baseline and 6 months (expressed in mm^3) | 6 and 12 months | 
| Ultrasonographic tissue perfusion | Tissue perfusion changes over the healing assessed with ultrasonography (expressed in cm/s) | Baseline, 1 week, 2 weeks, 1 month, 3 months, 6 months and 12 months | 
| Post-operative morbidity | Patient-reported outcome assessed using a daily questionnaire first the first 4 weeks (expressed as a number using a 0-100 visual analogue scale [VAS]) | Daily, for the first 4 weeks after the procedure | 
| Treatment satisfaction | Patient-reported outcome assessed with questionnaire including a 0-100 visual analogue scale (VAS) at the last visit (expressed as a number) | 12 months | 
| Esthetic assessment | Patient-reported outcome assessed with questionnaire including a 0-100 visual analogue scale (VAS) at the initial and last visit (expressed as a number) | Baseline and 12 months | 
| Ultrasonographic strain elastography | Changes in the elasticity of the soft tissue over the healing assessed with ultrasonography (expressed as a ratio) | Baseline, 3 months, 6 months and 12 months |