Block Versus Particulate Deproteinized Bovine Bone Mineral for Guided Bone Regeneration of Peri‐Implant Dehiscence Defects: A 5‐Year Randomized Controlled Trial

To assess the 5‐year dimensional stability of buccal hard‐tissues following guided bone regeneration (GBR) of peri‐implant dehiscence defects using deproteinized bovine bone mineral (DBBM) blocks or particulate.

Methods

Patients requiring single‐tooth implants and presenting a buccal dehiscence defect (≥ 3 mm) at implant placement were randomly allocated to GBR using either particulate DBBM or an individually shaped DBBM‐block, both covered with a resorbable collagen membrane. Buccal hard‐tissue thickness was assessed using cone‐beam computed tomography postoperatively, at 6 months and at 5 years. Buccal horizontal thickness at the implant shoulder and corono‐buccal thickness measured at 45° were recorded. Secondary outcomes included marginal bone levels, clinical parameters and implant survival. Linear mixed‐effects models were used to compare the groups to account for within‐subject correlations.

Results

Twenty‐two of 24 patients completed the 5‐year follow‐up. Buccal hard‐tissue thickness decreased over time in both groups, however, the block‐group showed significantly greater dimensional stability. At 5 years, mean buccal horizontal hard‐tissue thickness was 1.36 ± 1.16 mm in the block‐group and 0.07 ± 0.16 mm in the particulate‐group (adjusted mean difference, −1.2 mm; 95% CI, −1.9 to−0.6; p  < 0.001). Corono‐buccal thickness at 45° was also significantly greater in the block‐group (adjusted mean difference, −0.3 mm; 95% CI, −0.5 to −0.1; p  = 0.002). Marginal bone levels and clinical parameters showed no clinically relevant differences. No implant loss or peri‐implantitis was observed.

Conclusion

GBR using either DBBM blocks or particulate DBBM resulted in similar peri‐implant clinical outcomes and implant survival at 5 years. However, DBBM blocks provided superior long‐term preservation of the buccal hard‐tissue contour.

Trial Registration

Clinical Trial Registration Number, DRKS00005803