A randomized-controlled clinical trial evaluating clinical and radiological outcomes after 3 and 5 years of dental implants placed in bone regenerated by means of GBR techniques with or without the addition of BMP-2.

OBJECTIVE: The aim of this randomized-controlled clinical trial was to evaluate the long-term outcome of implants placed in bone augmented with a xenogenic bone substitute material and a collagen membrane with or without the addition of recombinant human bone morphogenetic protein-2 (rhBMP-2). MATERIAL AND METHODS: Eleven patients received a total of 34 implants placed into sites exhibiting lateral bone defects. In a split mouth design, the defects were randomly treated with the graft material and the collagen membrane either with (test) or without (control) rhBMP-2. The patients were examined 3 and 5 years after insertion of the prosthetic restoration. Student's paired t-test was performed to detect differences between the two groups. RESULTS: The survival rate at 3 and 5 years was 100% for both groups. The peri-implant soft tissues were stable and healthy without any difference between the two groups. The prosthetic reevaluation demonstrated four loose prosthetic screws during the first 3 years and seven ceramic chippings after 3 and 5 years. The mean distance between the first bone to implant contact to implant abutment junction at 3 years was 1.37 mm (test), 1.22 mm (control), and 1.38 mm (test), and 1.23 mm (control) at 5 years. The difference of <0.2 mm between test and control implants was not statistically significant. The mean change of the marginal bone level between baseline and 5 years ranged from -0.07 mm (mesial, test), -0.11 mm (distal, test), -0.03 mm (mesial, control), to +0.13 mm (distal, control). No statistically significant differences were observed between test and control sites. CONCLUSION: Implants placed in bone augmented with and without rhBMP-2 revealed excellent clinical and radiological outcomes after 3 and 5 years.

A new optical method to evaluate three-dimensional volume changes of alveolar contours: a methodological in vitro study.

OBJECTIVES: The aim of this study was to evaluate the reproducibility and the accuracy of volumetric measurements of specimens imitating localized alveolar ridge defects using an optical three-dimensional (3D) system. MATERIAL AND METHODS: Eight pairs of specimens (five with a cuboid and three with a geometrically complex form) were used for the measurements. Each of them imitated a pre-operative ridge defect and a corresponding surgically corrected post-operative situation. The true volume differences between two corresponding specimens were either assessed by a mechanical 3D coordinate measuring machine or by computer calculation (controls). For the test measurements, an optical 3D system with a newly developed software for volume measurements was utilized. The volumes of the specimen pairs were captured and the data digitized. The volume differences between the simulated pre- and post-operative situations were calculated by subtracting the two values obtained. The accuracy of the optical 3D system was assessed comparing the test and the control values. The difference between these values described the systematic error of the test method. The reproducibility was evaluated by calculating the coefficients of variation of repeated test volume measurements. Descriptive statistics were applied. RESULTS: The accuracy of the optical 3D system was very high with differences between test and control measurements never exceeding 1.5%. The systematic error of the test measurements was consistently below 2.5 mm3. The reproducibility of the measurements showed very low coefficients of variation ranging from 0.05% to 0.5%, indicating excellent reproducibility. CONCLUSIONS: The tested optical 3D system showed excellent accuracy and high reproducibility for measuring volume differences between specimens imitating localized alveolar ridge defects before and after augmentation procedures.