Local Vascularization during Orthodontic Tooth Movement in a Split Mouth Rat Model—A MRI Study

Abstract

Orthodontic tooth movement to therapeutically align malpositioned teeth is supposed to impact blood flow in the surrounding tissues. Here, we evaluated actual vascularization in the tension area of the periodontal ligament during experimental tooth movement in rats (N = 8) with magnetic resonance imaging (MRI). We inserted an elastic band between the left upper first and the second rat molar; the right side was not treated and served as control. After four days of tooth movement, we recorded T1-weighted morphologic and dynamic-contrast-enhanced MRI sequences with an animal-specific 7 Tesla MRI to assess of local vascularization. Furthermore, we quantified osteoclasts and monocytes in the periodontal ligament, which are crucial for orthodontic tooth movement, root resorptions as undesirable side effects, as well as the extent of tooth movement using paraffine histology and micro-CT analysis. Data were tested for normal distribution with Shapiro–Wilk tests followed by either a two-tailed paired t-test or a Wilcoxon matched-pairs signed rank test. Significant orthodontic tooth movement was induced within the four days of treatment, as evidenced by increased osteoclast and monocyte activity in the periodontal ligament as well as by µCT analysis. Contrast enhancement was increased at the orthodontically-treated side distally of the moved upper first left molar, indicating increased vascularization at the tension side of the periodontal ligament. Accordingly, we detected reduced time-to-peak and washout rates. Our study using MRI to directly assess local vascularization thus seems to confirm the hypothesis that perfusion is enhanced in tension zones of the periodontal ligament during orthodontic tooth movement.

Dynamic Changes in Tooth Displacement and Bone Morphometry in Orthodontic Tooth Movement in Rats: A 3D Analysis

“…From digital calipers to intraoral scanners, from histology to cephalograms and from 2D to 3D, the methodology to measure in vivo OTM has been developing for years [19,[25][26][27][28][29][30] . Although the measurements became more and more accurate, the evaluation of the dynamic changes induced by OF still remains di cult, as it is hard to nd a reliable reference structure.…”

Assessment of the Effect on Periodontitis of Antibiotic Therapy and Bacterial Lysate Treatment

“…Therefore, research on animal models is necessary to establish cause-effect relationships and, equally important, to test new regenerative devices and advanced therapies [9]. In rats, periodontal disease is an infectious process caused by periodontal pathogens resulting in specific lesions [10]. Thus, rodents are suitable for research targeting teeth or investigating the dynamics of oral inflammatory diseases, and the information gained in this way allows for the translation of basic science into applied research.…”

Models for Oral Biology Research

“…It is assumed that orthodontic tooth movement affects blood flow in the surrounding tissues; in this way. Proof et al [13] evaluated the vascularization in the area of tension of the periodontal ligament during experimental tooth movement in rats by magnetic resonance imaging (MRI). The authors also quantified osteoclasts and monocytes in the periodontal ligament, and the extent of tooth movement using paraffine histology and micro-CT analysis.…”