Accelerated Orthodontic Tooth Movement With Flapless Corticotomy: A Pilot Study in Beagle Dogs

Surgical injury to alveolar bone can temporarily accelerate orthodontic tooth movement by increasing the remodeling rate of alveolar bone and decreasing its mineral density, thus decreasing the mechanical resistance of dento-alveolar tissues to orthodontic load. A simple bone perforation procedure (flapless corticotomy) was tested in this pilot study using Beagle dogs and compared to a traditional flap corticotomy.;Objectives: To determine differences in amount and type of tooth movement between flap and flapless corticotomy groups after 8 weeks of orthodontic force application.;Methods: Five unrelated Beagle dogs, aged approximately 15 months, were used in this study. All third premolars were extracted; fourth premolars and temporary anchorage devices were used as anchors and second premolars were moved distally towards the extracted third premolar positions utilizing a novel experimental orthodontic appliance. Orthodontic force of 1.5 N (153 gram or 5.4 oz) was generated with Ni-Ti closed coil spring in every appliance. Apical and coronal measurements of tooth movement were recorded weekly by measuring the distance between 2 separate permanent indentations on the canine and second premolars with a digital caliper accurate to 0.01 mm; tooth movement was followed for 8 weeks. Data analysis was performed by Wilcoxon Signed Rank Test.;Results: Bodily movement of 0.18--1.77 mm in 8 weeks was achieved. No gross tipping or rotation was observed. No statistically significant difference in amount or type of tooth movement was found between flap and flapless groups at 8 weeks. All appliances remained intact until the end of the study.;Conclusions: The flapless corticotomy procedure is feasible in Beagle dogs. The newly designed orthodontic appliance achieved bodily movement in Beagle dogs. We were unable to show a difference in the amount or types of tooth movement between the flapless and flap groups at 8 weeks possibly due to the small sample size and high variability. It could also be true that no difference exists.