MicroCT analysis of bone mineral density in rats with experimental orthodontics and hypercholesterolemia

Abstract

Objective: To determine the Bone Mineral Density (BMD) and Cortical Mineral Density (CMD) of hypercholesterolemic rats subjected to distalizing orthodontic forces towards a post-extraction alveolus.

Methods: Methodology:48 freshly weaned Wistar rats (60 ± 5 g) were divided into two groups.G1: fed a control diet (DC).G2: hypercholesterolemic diet(DHC).At 3 weeks, exodontia of the lower left second molar and installation of an orthodontic appliance (OE) for two weeks on the first molar were performed. At week 5, euthanasia was performed. Blood was obtained by cardiac puncture to study lipid profile (mg/dL), total cholesterol (TC),C-HDL, C-noHDL and triglycerides. Microtomographies of the hemimandibles were performed with a Microtomograph (Skyscan 1272,Bruker. Diagnostic Imaging Department,FOUBA).8 µm resolution for qualitative analysis: BMD(gr/cm3) of the interradicular bone (HI),the DM-cortical (DMC)(gr/cm3) of the vestibular cortical(CV) and lingual cortical(CL) Software Ctan 1.18. Statistical analysis:non-parametric tests. Student's t-test, p<0.05. Modified Shapiro-Wilks test and Mann-Whitney U test (p<0.05).InfoStat program. Results were expressed as X±DS and median (Q1/Q3).

Results: BMD (% gr/cm3) for HI G1: 2.36 (1.96/2.52) vs G2: 1.44 (1.39/1.53). The BMD (% gr/cm3) for VC G1: 2.10 (2.07/2.15) vs G2 :0.75(0.63/1.00); for CL G1:1.70 (1.61/1.72) vs G2: 0.46 (0.34/0.50). All results were statistically significant (p<0.05).

Conclusions: Experimental orthodontics in hypercholesterolemic rats leads to impaired alveolar bone mineral density.