Resorption of roots of different dimension induced by different types of forces

Abstract

Root resorption is a variable to be considered in induced tooth movement (ITM). It is related to root morphology and alveolar bone crest, and also to the types of forces exerted by mechanotherapy. This histometric study evaluated the predominance of root resorption among roots of different dimensions, following ITM with different types of forces and at different time intervals. The study was conducted on 54 rats divided into three groups, according to the type of force: continuous (CF), continuous interrupted (CIF) and intermittent (IF), at periods of 5, 7 and 9 days. The percentage of resorption between mesiobuccal roots of larger dimension and intermediate roots of smaller dimension was assessed. The evaluations were performed on the AxioVision software, and the non-parametric analysis of variance for repeated measures in independent groups was further applied, consisting of a scheme of two factors, and complemented by the Dunn test at a significance level of 5%. The intermediate roots presented a higher percentage of resorption, which was gradual at the periods evaluated for the three types of forces, but mainly for CF. Comparing the intermediate roots with the mesiobuccal roots, there was a statistically significant difference (p < 0.05) in the CF group at day 7 and day 9, and in the FI group, at day 9. The intragroup analysis evidenced a statistically significant difference (p < 0.05) between the 5 th and the 9 th day for the intermediate root in the CF group. The intergroup analysis did not reveal any statistically significant difference (p > 0.05) in individually analyzed roots.

Intermittent compressive force promotes osteogenic differentiation in human periodontal ligament cells by regulating the transforming growth factor-β pathway

“…Furthermore, CCF treatment did not significantly alter the expression of HES1 mRNA, while a significant upregulation of HES1 was observed after ICF treatment 11 . Moreover, in an in vivo OTM model, CCF generated more intermediate root resorption than that of ICF application 12 . Correspondingly, histomorphometrical analysis illustrated that the percentage of osteoclast length per bone length is lower after ICF treatment compared with CCF treatment in rat molars 13 .…”

“…Hence, these results indicate the influence of different force types on hPDL behavior. Studies illustrate that CCF and intermittent compressive force (ICF) differentially regulate hPDL behavior 11,12 . CCF and ICF both significantly increased SOST, TGFB1, and HEY1 mRNA expression in hPDLs 11 .…”

Effects of Zoledronic Acid on Orthodontic Tooth Movement in Rats

“…Root resorption is a well-known, adverse effect of orthodontic treatment. In assessing the conditions of the tooth and periodontal ligament of rats subjected to orthodontic movement, the presence of areas of root resorption is reported (24,25).…”

Orthodontically induced root resorption: An updated review

“…In more detail, light orthodontic forces usually tend to result in mild root resorption, while archwire sequencing, bracket prescription and self-ligation appear to do not affect the root length 23 . During tipping movement, the apex absorbs all the compressive stress, resulting in increased stress per unit surface area 4, 24,25 . In contrast, translation movement generates compressive stress to the entire root surface, which causes cementum resorption at the sides of periodontal ligament compression.…”

“…Thin and elastic type of alveolar bone has the ability to absorb increased οrthodontic mechanical stress than thick and more rigid alveolar bone 25. As a result, alveolar bone density has a critical role in the development of root resorption 26 .…”