The Influence of Mucosal Tissue Thickness on Soft and Hard Tissue Changes Around Implants. A Randomized Controlled Clinical Study

The objectives of this clinical study are;

• to evaluate the influence of mucosal tissue thickness on periimplant soft and hard tissue changes.
• to evaluate whether acellular dermal matrix (ADM) derived allogenic membrane or subepithelial connective tissue grafts performed at implant placement could be effective in vertical soft tissue augmentation.
• to evaluate the influence of vertical soft tissue augmentation with acellular dermal matrix or subepithelial connective tissue grafts on soft and hard tissue changes around implants with platform switching after 1 year of loading.

Partially edentulous patients in the posterior lower jaw area requiring implant treatment will be recruited for this study. There will be four groups in the study with 35 patients in each group.

Inclusion criteria will be; (1) >18 years of age; (2) no medical contraindication for implant surgery; (3) missing teeth in the posterior mandibular area requiring two implants supported three unit bridge prosthetic restoration; (4) fully healed bone sites (at least 3 months after extraction) (5) minimum of 6mm bone width and 10 mm bone height above inferior alveolar canal; (6) healthy soft tissue; (7) minimum 2mm keratinized gingiva; (8) no bone augmentation procedures before and during implant placement. The patients will be excluded if they will not meet inclusion criteria and additionally have (1) poor oral hygiene; (2) uncontrolled periodontitis (3) smoking Ethical approval was taken from Cukurova University Ethical Committee and the patients will sign informed consent form before participating in the study. Cone beam computerized tomography will be taken from all patients in order to evaluate the future implant sites. Patients will be enrolled if they fulfill the inclusion criteria. Patients will be excluded if they will not meet inclusion criteria and additionally have exclusion criteria. Two implants per patient will be placed. The prosthetic restorations will be performed as three unit bridge with two supported implants. These two implants in the premolar and molar regions will be included into the study and evaluated independently.

One hour prior to surgery the patients will receive prophylactic dose of 1 g amoxicillin+clavulanic acid. All surgical procedures will be performed by two experienced surgeons under local anesthesia. A mid-crestal incision on the center of edentulous ridge will be performed, leaving at least width of 2 mm keratinized tissues buccally. Next, a full-thickness buccal flap will be raised, while lingual part will not be elevated to ensure direct visibility. Vertical thickness of soft tissues will be measured with 1.0 mm marked periodontal probe. The probe will be positioned in an upright position to the bone crest in the center of the future implant placement. After measurement, lingual flap will be raised to completely expose the implantation site. If vertical soft tissue thickness is 2 mm or less, tissues will be considered as thin. If soft tissue thickness is more than 2mm, tissues will be considered as thick. There will be four groups in the study.