Stability of subepithelial Connective Tissue Graft or volumetrically stable Collagen Matrix for ridge volume augmentation: split-mouth randomized controlled clinical trial

It has been showed that thick peri-implant mucosa optimizes health and longevity. Connective tissue grafts are considered the “gold standard”, however, soft tissue substitutes are an alternative to decrease patient morbidity. The aim of this randomized controlled split-mouth clinical trial is to assess the soft tissue thickness after implant reopening and grafting using a connective tissue graft or collagen matrix in the posterior mandible. Eight patients who had submerged implants installed bilaterally and reduced soft tissue thickness were randomly assigned to receive a connective tissue graft or collagen matrix at each side. A reopening procedure was performed and implants received a personalized healing abutment and a soft tissue graft. Data was collected from the patients at 3 different time points: baseline, 3, and 18 months. Linear measurements were made at alveolar ridge crest, 1, 2, and 3 mm below. Time of surgery and patient related outcomes were assessed. Intragroup assessments showed an increase in soft tissue thickness at all time points compared to baseline on both groups. Intergroup comparison showed a significant difference favoring connective tissue graft where there was a greater gain of soft tissue thickness and stability throughout time. The average gain of soft tissue thickness from baseline to 18 months on connective tissue graft and collagen matrix groups were 2.08±0.98 mm and 0.82±0.47, respectively. The type of graft did not influence postoperative morbidity while surgery time was higher in the connective tissue graft group. Sites that received a connective tissue graft presented higher soft tissue thickness gain. Soft tissue thickness was stable over time in group connective tissue graft and showed a decrease in group collagen matrix after 18 months