Guided tissue regeneration therapy of 203 consecutively treated intrabony defects using a bioabsorbable matrix barrier. Clinical and radiographic findings.

THE AIM OF THIS RETROSPECTIVE three-center study was to evaluate guided tissue regeneration (GTR) therapy in a clinical periodontal setting. The material consisted of 203 consecutively treated intrabony defects > or = 4 mm in 143 patients using a bioabsorbable matrix barrier. Each center followed the same protocol for presurgical, intrasurgical, and follow up examinations. Initial therapy, surgical, and follow-up treatments followed the routine of each center. Treatment was evaluated after 1 year by clinical assessments for probing depth (PD) reduction and clinical attachment level (CAL) gain and by bone fill from computer digitized radiographs. Initial intrabony defect depth averaged 6.3 +/- 1.0 mm clinically and 5.7 +/- 1.8 mm radiographically. Mean PD was reduced from 9.0 +/- 1.0 mm to 3.3 +/- 1.0 mm. Mean CAL gain amounted to 4.8 +/- 1.5 mm corresponding to 79 +/- 13% of the initial intrabony defect depth; 78% of the defects exhibited CAL gain > or = 4 mm. Bone fill averaged 3.2 +2- 1.8 mm. Together with a crestal resorption of 1.1 +/- 1.4 mm this resulted in a defect resolution of 4.3 +/- 1.9 mm or 72%. Forty-seven percent (47%) of the variability in CAL gain could be explained by defect depth, defect width, early barrier exposure, and presence of plaque in the treated area. CAL gain and bone fill were positively correlated to the intrabony defect depth; i.e., the deeper the defect the more the CAL gain and bone fill. Sites with barrier exposure during the first 2 weeks of healing showed significantly less CAL gain than sites at which exposure occurred at a later stage or not at all. Presence of plaque in the treated area had a significant negative impact on both CAL gain and bone fill. It was concluded that GTR-treatment of intrabony defects > or = 4 mm in a periodontal specialist practice will result in clinical attachment level gain and bone fill comparable to what has been demonstrated in case studies and controlled clinical trials. The predictability to obtain CAL gain > or = 4 mm in defects > or = 4 mm was 78%.