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Dental Press Journal of Orthodontics

On-line version ISSN 2176-9451

Abstract

SELLA, Rodrigo Castellazzi; MENDONCA, Marcos Rogério de; CUOGHI, Osmar Aparecido  and  AN, Tien Li. Histomorphometric evaluation of periodontal compression and tension sides during orthodontic tooth movement in rats. Dental Press J. Orthod. [online]. 2012, vol.17, n.3, pp. 108-117. ISSN 2176-9451.  http://dx.doi.org/10.1590/S2176-94512012000300021.

OBJECTIVE: The purpose of this study was to evaluate the thickness of the periodontal ligament of rat molars during orthodontic tooth movement (OTM). METHODS: Thirty Wistar rats were divided into three groups of 10 animals each: GI, GII and GIII and the mice were euthanized at 7, 14 and 21 days, respectively. Experimental subjects were compared to their respective controls by the Mann-Whitney test. Comparison of values between compression and tension sides were performed during the same and different time periods through Analysis of Variance (ANOVA), Kruskal-Wallis test and, subsequently, Tukey's test. RESULTS: Groups GI and GII showed decreased PDL size in the apical regions of the mesiobuccal root and in the cervical region of the distobuccal root. There was also an increased PDL in the cervical regions of the mesiobuccal root, apical region of the distobuccal root and middle region of both roots. CONCLUSION: The reduction and increase in PDL size were seen in the same root, which characterizes tooth inclination. The apical, middle and cervical regions were compared with one another in each time period and at three times: 7, 14 and 21 days. They were also compared in each region, confirming a tipping movement in GI and GII and a gradual decreased intensity between GI to GII, reaching normal dimension in GIII.

Keywords : Tooth movement; Periodontal ligament; Periodontium.

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