Development of root resorption during orthodontic tooth movement after cleft repair using different grafting materials in rats

Objective The aim of the present study was to investigate the influence of three grafting materials for cleft repair on orthodontic tooth movement in rats. Materials and methods Artificial alveolar clefts were created in 21 Wistar rats and were repaired 4 weeks later using autografts, human xenografts and synthetic bone substitute (beta-tricalcium phosphate/hydroxyapatite [beta-TCP/HA]). A further 4 weeks later, the first molar was moved into the reconstructed maxilla. Microfocus computed tomography (mu CT) was performed six times (T0-T5) to assess the tooth movement and root resorption. After 8 weeks, the affected reconstructed jaw was resected for histopathological investigation. Results Total distances reached ranged from 0.82 +/- 0.72 mm (beta-TCP/HA) to 0.67 +/- 0.27 mm (autograft). The resorption was particularly determined at the mesiobuccal root. Descriptive tooth movement slowed and root resorption increased slightly. However, neither the radiological changes during tooth movement (mu CT T1 vs. mu CT T5: autograft 1.85 +/- 0.39 mm(3) vs. 2.38 +/- 0.35 mm(3), p = 0.30; human xenograft 1.75 +/- 0.45 mm(3) vs. 2.17 +/- 0.26 mm(3), p = 0.54; beta-TCP/HA: 1.52 +/- 0.42 mm(3) vs. 1.88 +/- 0.41 mm(3), p = 0.60) nor the histological differences after tooth movement (human xenograft: 0.078 +/- 0.05 mm(2); beta-TCP/HA: 0.067 +/- 0.049 mm(2); autograft: 0.048 +/- 0.015 mm(2)) were statistically significant. Conclusion The autografts, human xenografts or synthetic bone substitute used for cleft repair seem to have a similar effect on the subsequent orthodontic tooth movement and the associated root resorptions.