Soft Tissue Augmentation Around Dental Implants

The Use of Collagen Matrices and Connective Tissue Grafts for Soft Tissue Augmentation Around Dental Implants

The goal of this study is to determine which method better increases the volume of soft tissues (gums) around dental implants: using the patient's own tissues or applying collagen matrices. The study also evaluates the safety of these methods and their impact on smile aesthetics.

The main questions it aims to answer:

Which method provides greater and more stable increase in gum thickness around the implant? Does the choice of material affect gum color (how well it matches adjacent areas)? What features of healing and cellular tissue structure are observed when using different materials?

Researchers will compare:

Autogenous connective tissue grafts (CTG) - the patient's own connective tissue grafts harvested from the palate or maxillary tuberosity Xenogeneic collagen matrices (XCM) - bioresorbable materials of animal origin (Fibro-Gide® and FibroMatrix®) that do not require harvesting the patient's own tissue

Participants will:

Undergo a surgical procedure to increase soft tissue volume in the area of implant placement (using one of four methods assigned randomly)

Attend clinic visits for follow-up examinations and assessments:

• Before surgery
• 3 months after surgery
• 6 months after surgery

Undergo additional examinations:

• 3D intraoral scanning to assess changes in tissue volume
• Cone-beam computed tomography (CBCT) to measure gum thickness
• Polarized-light photography to evaluate gum color
• Collection of a small tissue sample (biopsy) for laboratory analysis of tissue structure and cellular composition

Study Overview

• Status: Completed
• Conditions: Peri-implant Soft Tissue Augmentation; Dental Implant Rehabilitation
• Intervention / Treatment: Procedure: Connective Tissue Graft (Palate); Procedure: Connective Tissue Graft (Tuberosity); Device: Fibro-Gide Collagen Matrix; Device: FibroMatrix Collagen Matrix

• Study Type: Interventional
• Enrollment (Actual): 84
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Russia
  • Moscow, Russia, 119021
    • Central Research Institute of Dental and Maxillofacial Surgery

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age between 21 and 75 years
• Requirement for single dental implant placement in the mandibular molar region (replacing no more than one tooth)
• Need for soft tissue augmentation to achieve peri-implant mucosal thickness ≥2 mm
• Signed voluntary informed consent for treatment and research participation
• Ability and willingness to attend all scheduled follow-up examinations for 12 months post-surgery
• Adequate oral hygiene and commitment to maintain it throughout the study period

Exclusion Criteria:

• Presence of systemic diseases in a decompensated stage (e.g., uncontrolled diabetes, severe cardiovascular disease)
• Current or prior use of immunosuppressants, bisphosphonates, or high-dose corticosteroids
• History of cancer, radiation therapy, or chemotherapy within 5 years prior to enrollment
• Need for concurrent bone grafting or immediate implant placement following tooth extraction
• Active periodontal disease or untreated oral infections at the time of surgery
• Heavy smoking (>10 cigarettes/day) or inability to abstain from smoking during the healing period
• Pregnancy or lactation
• Known allergy to collagen, porcine/bovine products, or materials used in the study (sutures, anesthetics)
• Participation in another clinical trial within 30 days prior to enrollment
• Refusal to participate in any stage of the study or inability to comply with study procedures
• Psychological or social conditions that, in the investigator's judgment, may compromise protocol adherence or data reliability

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Palate CTG; Subepithelial connective tissue graft harvested from the hard palate, placed at the implant site to augment soft tissue thickness and volume	Procedure: Connective Tissue Graft (Palate); Autogenous subepithelial connective tissue graft harvested from the hard palate (premolar-molar region) using a horizontal incision 2-3 mm apical to the gingival margin. Epithelium removed microscopically. Graft secured within a soft-tissue "envelope" at the recipient implant site using U-shaped sutures. Donor site closed with compression sutures.
Experimental: Tuberosity CTG; Subepithelial connective tissue graft harvested from the maxillary tuberosity, placed at the implant site to augment soft tissue thickness and volume	Procedure: Connective Tissue Graft (Tuberosity); Autogenous subepithelial connective tissue graft harvested from the maxillary tuberosity using parallel incisions 2 mm distal to the last molar. Epithelial strip removed. Graft placed and secured at the implant site using U-shaped suturing technique. Donor site closed with interrupted sutures.
Experimental: Fibro-Gide; Xenogeneic collagen matrix (porcine-derived, types I/III collagen), trimmed and placed between the flap and bone to augment soft tissue	Device: Fibro-Gide Collagen Matrix; Porcine-derived xenogeneic collagen matrix (types I/III), 6 mm thick, gamma-sterilized. Trimmed to fit recipient site, placed between flap and bone without suturing to the flap, fully covered by soft tissues during closure. No donor site required.
Experimental: FibroMatrix; Xenogeneic collagen matrix (bovine pericardium-derived, types I/III collagen), trimmed and placed between the flap and bone to augment soft tissue	Device: FibroMatrix Collagen Matrix; Bovine pericardium-derived xenogeneic collagen matrix (types I/III), 3-4 mm thick, freeze-dried, bilayer structure. Trimmed to fit recipient site, placed between flap and bone without suturing to the flap, fully covered by soft tissues during closure. No donor site required.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in peri-implant soft tissue thickness from baseline to 6 months post-augmentation	The primary outcome is the mean change in vertical soft tissue thickness at the implant site, measured at three equidistant points (crest, 1 mm apical, 2 mm apical) along the vestibular aspect of the alveolar ridge. Thickness is assessed using three complementary methods: (1) mucosal puncture with a calibrated spreader and silicone stopper under local anesthesia; (2) superimposition of cone-beam computed tomography (CBCT) scans; and (3) comparison of digital 3D intraoral scans (STL files) using GOM Inspect software. Measurements are averaged across the three points per site. The primary analysis compares mean thickness gain between the four intervention groups (palate CTG, tuberosity CTG, Fibro-Gide, FibroMatrix) at 6 months.	Baseline (pre-surgery), 3 months post-surgery, and 6 months post-surgery

Collaborators and Investigators

• Sponsor: Andrey Vasilyev

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2021
• Primary Completion (Actual): October 1, 2024
• Study Completion (Actual): October 1, 2024

Study Registration Dates

• First Submitted: May 18, 2026
• First Submitted That Met QC Criteria: May 18, 2026
• First Posted (Actual): May 22, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 18, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 1/20

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared publicly. This decision is based on: (1) the single-center, academic nature of the study with a relatively small sample size, which increases re-identification risk even after de-identification; (2) the inclusion of detailed clinical, radiographic, and histological data that may contain sensitive personal health information; (3) ongoing secondary analyses and manuscript preparations by the investigative team; and (4) the absence of a dedicated infrastructure for secure, governed data sharing at this institution.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No