Interdental osteotomies induce regional acceleratory phenomenon and accelerate orthodontic tooth movement

Purpose Although it has been revealed clinically that double-jaw orthognathic surgery induces a systemic increase in the baseline bone turnover and subsequently accelerates postoperative orthodontic tooth alignment, it is not clear whether less extensive osteotomy, such as interdental osteotomy, would be intensive enough to accelerate postoperative orthodontic tooth alignment. Materials and Methods Twelve adult male beagle dogs were randomly assigned to 2 groups. The sham control group (n = 6) received orthodontic tooth alignment of the maxillary incisors, and the experimental group (n = 6) received orthodontic tooth alignment of the maxillary incisors and interdental osteotomies between the maxillary third incisor and canine on both sides concurrent with the beginning of orthodontic tooth alignment. The duration of orthodontic tooth alignment was 3 months in both groups. Cone-beam computed tomography scans of the maxilla, dental casts, blood samples, and gingival crevicular fluid (GCF) of the maxillary incisors were taken immediately before orthodontic tooth alignment (T0) and 1 week (T1) and 1 (T2), 2 (T3), and 3 (T4) months after beginning orthodontic tooth alignment. They were analyzed for changes in the interdental alveolar bone gray scale (osteoporosity) of the maxillary incisors, irregularity index (rate of orthodontic tooth alignment), and bone-specific alkaline phosphatase (bALP, a biomarker of osteoblastic activity) and C-terminal telopeptide of type I collagen (ICTP, a biomarker for osteoclastic activity) in the serum and GCF samples from T0 to T4. The data were analyzed statistically for inter- and intragroup differences. Results The rate of orthodontic tooth alignment for the experimental group was significantly greater and twofold that of the sham control group at T1, T2, T3, and T4. The serum-bALP, serum-ICTP, GCF-bALP, GCF-ICTP, and osteoporosity remained similar from T0 to T4 in the sham control group. In contrast, GCF-bALP increased two- to threefold from T1 to T4, and GCF-ICTP increased fivefold at T1 and then gradually decreased from T2 to T4. The interdental osteoporosity significantly increased from T1 to T4, but the serum-bALP and serum-ICTP levels remained similar, without significant changes in the experimental group. Conclusions Interdental osteotomy induced a regional, but not a systemic, acceleratory phenomenon and was intensive enough to accelerate postoperative orthodontic tooth alignment twofold. The intensity of the increase in the bone turnover rate and osteoporosity might depend on the extent of the osteotomy.