Consolidation Period in Alveolar Distraction: A Pilot Histomorphometric Study in the Mandible of the Beagle Dog

Purpose: Osteogenic alveolar distraction remains in an experimental stage. The present study aimed to compare histologic and histomorphometric results with 2 different consolidation periods (4 and 8 weeks) to determine which period obtained better bone quality after distraction with a prototype alveolar distractor. Materials and Methods: Five beagle dogs were used. Four underwent alveolar distraction in an edentulous segment of the right mandible. After a 7-day latency period, distraction was carried out at a rate of 1 mm/d for 5 days; the consolidation period was 4 weeks in 2 dogs (group 1), and 8 weeks in the other 2 (group 2). The fifth dog was used as control (group 3); it underwent removal of its right premolars but not distraction. Histologic and histomorphometric studies were conducted. Results: One animal from each distraction group was withdrawn from the study because of wound dehiscence that allowed invasion of mucosa into the distraction chamber, which was incompatible with bone regeneration. In the group 1 animal, a predominance of immature woven bone was observed in the distraction chamber, whereas the group 2 animal showed a predominance of immature parallel-fibered bone. The group 1 and 2 animals that remained in the study differed in bone area density in the distraction chamber (36.61% ± 9.79% versus 58.72% ± 8.30%), bone perimeter in the distraction chamber (262.89 ± 10.46 mm versus 201.44 ± 22.64 mm), total height attained (21.31 ± 0.32 mm versus 18.37 ± 0.50 mm), lingual trabecular width (134.00 ± 15.56 versus 229.50 ± 29.24), buccal trabecular width (90.00 ± 4.24 mm versus 154.50 ± 21.64 mm), lingual osteoid area density (4.08% ± 0.46% versus 1.61% ± 0.33%), and buccal osteoid area density (3.75% ± 1.28% versus 2.09% ± 0.79%). Conclusion: Quantitative and qualitative differences in newly formed bone were observed after 4 and 8 weeks of consolidation. These preliminary results serve as a basis for further experimental research with larger samples and for clinical studies. (Animal Study) (More than 50 references) Keywords: alveolar distraction, consolidation period, experimental oral surgery