Histological and histomorphometrical outcome after lateral guided bone regeneration augmentation of the mandible with different ratios of deproteinized bovine bone mineral and autogenous bone. A preclinical in vivo study

Objective: To test the hypotheses of no differences in (I) percentage of bone (POB), non-mineralized tissue (NMT), and deproteinized bovine bone mineral (DBBM), and (II) ingrowth of mineralized bone after lateral guided bone regeneration (GBR) augmentation of the mandible with different ratios of DBBM and particulate autogenous bone (PAB) at different time points. Material and methods: Twenty-four minipigs were randomly allocated into three groups. Lateral augmentation in 96 sites (4 in each animal) was performed unilaterally with a standardized quantity of grafting material in each animal with different ratios of DBBM and PAB (50:50, 75:25, 100:0) and autogenous bone block in combination with DBBM and covered with a collagen membrane. The percentage of different tissues in the graft and ingrowth of mineralized bone was assessed by histomorphometrical and histological analyses after 10, 20, and 30 weeks, respectively. Results: The POB was 54% (50:50), 50% (75:25), and 48% (100:0) after 10 weeks, 60% (50:50), 61% (75:25), and 60% (100:0) after 20 weeks, and 63% (50:50), 62% (75:25), and 62% (100:0) after 30 weeks. There was no significant difference between the groups at any time points. There was a significant increase in POB and a significant decrease in NMT for 75:25 and 100:0 from 10 to 30 weeks. All ratios demonstrated a non-complete ingrowth of mineralized bone into the graft after 10 weeks and complete mineralization after 30 weeks. Conclusion: Within the limitations of the present study, it seems like addition of autogenous bone to DBBM for LRA did not affect the bone formation nor graft incorporation after 10–30 weeks of healing. However, a prolonged healing time seems to result in an increased POB for all ratios.