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An evaluation of external apical root resorption after orthodontic treatment

Root resorption is a common problem encountered in all branches of dentistry but is more commonly seen in cases that had been treated orthodontically. Orthodontists are constantly improving materials and techniques to reduce undesirable side effects like root resorption. Therefore in this retrospective study the primary objective was to compare the amount of root resorption observed after active orthodontic treatment with three different appliance systems namely, Tip Edge, Modified Edgewise and Damon. The sample consisted of pre and post-treatment cephalograms of sixty eight cases that were treated in three different groups (i.e., techniques). Root resorption of the maxillary central incisor was assessed from pre- and post- treatment lateral cephalograms using two schemes. In the first method overall tooth length (Black, 1902) from the incisal edge to the apex was measured on both pre and post-treatment lateral cephalograms and root resorption was recorded as an actual millimetre loss of tooth length. Percentage shortening per tooth was also recorded.
The results were subjected to various statistical analyses. There was a significant upward linear trend (p=0.022) for root resorption from Group 1 (Tip Edge) to Group 3 (Damon). Statistical modeling illustrated that only baseline length (pre-treatment incisor length) was a significant confounder. Gender, race, age and treatment time did not have a significant influence on the amount of root resorption seen after orthodontic treatment. In the final analysis after having adjusted for baseline length it was found that there were no significant differences (p=0.133; ANCOVA) in the degree of root resorption observed after the active phase of orthodontic treatment between groups. Similarly the percentage of root resorption calculated did not differ significantly between groups (p=0.067). The result was also confirmed by following a non-parametric approach by doing an analysis of covariance (ANCOVA) in which data was allocated a rank value.
In the second method root resorption was visually evaluated by using the five grade ordinal scale of Levander and Malmgren (1988). It was found that majority of cases in the sample came under Grade1 and Grade 2 category of root resorption. The upward linear trend between actual measurements and visual measurements was found to be statistically significant (p=0.0183).
Date19 January 2012
CreatorsThomas, Elizabeth
Source SetsSouth African National ETD Portal
Detected LanguageEnglish

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