Root resorption during orthodontic tooth movements

Abstract

The aim of the study was to compare the extent of maxillary incisor root resorption during different orthodontic tooth movements using three different techniques, namely the basal intrusion arch, the three component arch, and levelling of the upper dental arch with the straightwire appliance. The radiographs of 49 subjects (20 males and 29 females) with a mean age of 14.5 years were taken at two time points: in groups 1 and 2 after the levelling phase and in group 3 immediately after placement of the archwire (T1) and in all groups after a period of 6 months (T2). The amount of root resorption of the central incisors was determined at T2. The average incisor resorption was different in the three groups, with group 2 (three component arch) showing greater resorption (0.46 mm) than groups 1 (basal arch) and 3 (straightwire) of 0.26 and 0.25 mm, respectively. Analysis of variance (ANOVA) demonstrated that differences in root resorption in the three groups were not significant. Wilcoxon paired test showed that the root resorption occurring between T1 and T2 in the three groups was not significant. There was also no significant difference among the rates of resorption in the three groups. Grouping the subjects on the basis of the extent of root resorption and the biomechanics used showed differences in the percentage of subjects with the least (<0.5 mm) and greatest (0.5-0.9 mm) amounts of root resorption between the three groups. This again showed that the technique of three component intrusion arch resulted in the greatest increase in root resorption.

Influence of orthodontic treatment on root resorption: a systematic review

“…Adults had more root resorption than children, but the results were not statistically different 5 . Intrusion and retraction, whether performed simultaneously or consecutively, do not affect root length 9 . The authors state that the most causal variable of root resorption in this movement would be the force applied, suggesting that 10 cN per incisor would be ideal.…”

“…The authors state that the most causal variable of root resorption in this movement would be the force applied, suggesting that 10 cN per incisor would be ideal. They suggest these claims should be substantiated by further studies 9 . Although torque is not the only causal aggravating factor to root resorption, it needs to be considered Orthodontic treatment with dental extraction is favorable to root resorption and the pattern of extraction was a significant factor.…”

“…Most root resorptions are clinically irrelevant, but if severe, they may influence tooth longevity 4 . Panoramic and periapical radiographs were used by authors [3][4][5][6][7]9 to assess root resorption and its relation to orthodontic treatment, although some authors 4 state that teleradiography is the technique with the best location method to compare root length before and after treatment.…”

“…Another limitation would be the uniformity of the analyzed teeth, in which some authors of this study 5,6 state that incisors are more prone to root resorption. The therapy 3 and force used in tooth movement is a variable to be considered 9 . The adequate force used for orthodontic movement without generating iatrogenic root resorption is still uncertain, and new studies should be performed 9 .…”

“…Periapical and/or panoramic radiographs were used to predict and anticipate possible root resorption of higher intensity 4,6,7,9 . Ramanathan & Hofman 9 (2009) radiographically assessed root resorption after fixed appliance bonding (T1) and after intrusion and retraction (T2), and found more root resorption in the intrusion and retraction stage when compared to other stages of the treatment.…”