Bone response to buccal tooth movements-with and without flapless alveolar decortication.

SUMMARY OBJECTIVE

To evaluate the biological response of alveolar bone surrounding maxillary second premolars to flapless alveolar decortication and moderate, continuous forces in a buccal direction.

MATERIALS AND METHODS

Using a randomized split-mouth experimental design, unilateral alveolar decortication was performed with a piezosurgery unit around the maxillary second premolars of six female dogs. The contralateral side received a sham surgery. The maxillary second premolars were moved buccally with archwires (initial 163.9 cN expansive force) for 9 weeks, followed by 2 weeks of consolidation. Intraoral, radiographic, and model measurements were performed to evaluate tooth movements; the amount and quality of surrounding bone were quantified using micro-CT; bone formation was evaluated histologically.

RESULTS

The experimental premolars were expanded and tipped significantly (P < 0.05) more than the control premolars (1.35 times and 2.05 times as much, respectively). Peak rates of tooth movement occurred around 5 weeks. Dehiscenses were observed on both the experimental and control sides, with no statistically significant side differences in buccal bone height (BBH). Micro-CT analyses showed less mature bone in the apico-buccal and cervico-lingual regions around the experimental teeth. Hematoxylin and eosin sections demonstrated fenestrations on the cervico-buccal bone on both sides. The experimental side showed substantially more new bone formation and modeling of apico-buccal, cervico-lingual, and buccal bone than the control side.

CONCLUSIONS

Archwire expansion resulted in reductions in BBH. Piezosurgical flapless alveolar decortication, in combination with archwire expansion, increased tooth movements and tipping and produced less bone, less dense bone, and less mature bone.