Dynamic changes in tooth displacement and bone morphometry induced by orthodontic force

Abstract

This study used a novel 3D analysis to longitudinally evaluate orthodontic tooth movement (OTM) and bone morphometry. Twelve-week-old male Wistar rats were subjected to OTM by applying a constant orthodontic force (OF) of 25cN between one of the upper first molars and a mini-screw. In vivo micro-CTs were taken before and after 10, 17, 24 and 31 days of force application, and superimposed by a novel and rigid voxel-based registration method. Then the tooth and alveolar bone segment at different time points became comparable in the same coordinate system, which facilitated the analysis of their dynamic changes in 3D. By comparison between time points and between OF and no OF sides, this study showed that the OTM rate was not constant through time, but conformed to a ‘V’ shape changing pattern. Besides, OF induced displacement of both loaded and unloaded teeth, and the latter mirrored the former in a delayed manner. In addition, bone morphometric changes synchronized with OTM rate changes, implying that a higher OTM rate was concomitant with more alveolar bone loss. The pressure and tension areas might not be in two opposite sides, but actually adjacent and connected. These findings might provide instructive evidence for both clinical, translational and basic research in orthodontics.

Biomimetic Periodontal Ligament Transplantation Activated by Gold Nanoparticles Protects Alveolar Bone

“…The sample size was calculated using a previous split‐mouth study. [ 33 ] A power analysis in the software G*Power 3.1 (Düsseldorf, Germany) suggested a total sample size of minimum 30 animals for ANOVA when assuming 90% power with α = 0.05.…”

“…The tooth movement of the maxillary first molar and changes in bone morphometry were evaluated by a rigid voxel‐based registration method as described previously. [ 33,61 ] First, the CT data captured at T1 were superimposed with the corresponding baseline scan at T0 based on the maxillary structures as a reference in MTM Scaffold Strain (KU Leuven, Leuven, Belgium). Second, the teeth and their surrounding alveolar bone at both T0 and T1 were delineated by the same investigator as a region of interest (ROI) in CTAnalyzer software (version 1.17.5, Bruker, Kontich, Belgium).…”

“…The current study aims to develop a novel, yet straightforward approach to protecting alveolar bone using biomimetic periodontal ligament transplantation activated by AuNCs. To test this strategy in vivo, a validated orthodontic animal model was used, [ 33 ] as orthodontic tooth movement is essentially a process of aseptic inflammation that leads to alveolar bone resorption. This method to investigate bone regeneration has several advantages over other models of alveolar bone loss induced by infection, trauma, tooth loss, or surgically inflicted defects.…”

A Novel Injectable Piezoelectric Hydrogel for Periodontal Disease Treatment

“…Micro-CT reconstruction was analyzed according to established protocols . The brightness and contrast of all images were adjusted through histogram standardization (0.00–0.15) to enhance accuracy and enable automated algorithmic analysis and image comparison . To assess the amount of regenerated bone tissue, the standard distance between the CEJ and ABC between M1 and M2 (defect location) was measured .…”

“…68 The brightness and contrast of all images were adjusted through histogram standardization (0.00−0.15) to enhance accuracy and enable automated algorithmic analysis and image comparison. 69 To assess the amount of regenerated bone tissue, the standard distance between the CEJ and ABC between M1 and M2 (defect location) was measured. 66 To assess the regenerated bone tissue volume, we measured the percentage of bone tissue in selected areas over four planes spaced by 90 μm along the occlusal/apical direction.…”