ORAL HEALTH EVIDENCE-BASED PRACTICE PROGRAM
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Title Clear Removable Aligners Cause Similar Rates of Orthodontically Induced External Apical Root Resorption Compared to Conventional Fixed Orthodontic Treatment
Clinical Question In orthodontic patients, do clear removable aligners prevent or reduce the occurrence of orthodontically induced external apical root resorption compared to conventional fixed orthodontic treatment?
Clinical Bottom Line For orthodontic patients, clear aligners cause similar rates of orthodontically induced external apical root resorption compared to conventional fixed orthodontic treatment. This is supported by a case-control study of 372 patients. In that study there was no statistically significant difference (P= 0.78) in the rates of orthodontically induced external apical root resorption between the two groups.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 27504821Iglesias-Linares/2016372 patients treated with aligners or fixed appliancesCase Control Study
Key resultsIn this study 12 clinical variables that can cause external apical root resorption such as ABO discrepancy index, vertical movement, apical displacement, and genetic disposition were considered. The ABO discrepancy index (P=.021) and the extent of incisor apical displacement in the sagittal plane (P=.001) had an increased risk of orthodontically induced external apical root resorption. Another variable that increased the rate of orthodontically induced external apical root resorption was the state of being homozygous for the T allele of interleukin 1 receptor antagonist gene (IL1RN) (odds ratio [OR] = 3.121; P < .001; 95% CI, 1.93-5.03). After considering clinical, radiographic, and genetic variables, the result of the study showed no statistically significant difference in orthodontically induced external apical root resorption between the clear aligners and the conventional fixed appliances, where the OR = 1.662 (P = .078; 95% CI, 0.945-2.924).
#2) 23941626Krieger/2013100 patients treated with clear aligners Retrospective study
Key resultsIn this study 100 patients treated with clear aligners were evaluated for orthodontically induced external apical root resorption. Root and crown lengths of 1,600 teeth were measured twice: before and after treatment. All patients had at least two teeth with less root length after treatment. On average 7.36 teeth per patient were affected. A reduction of > 0% and up to 10% of root length occurred in 27.75% of teeth. A greater reduction of > 10% and up to 20% occurred in 11.94% of the teeth. A more considerable reduction in root length, > 20%, occurred in 6.31% of teeth.
Evidence Search ("root resorption"[MeSH Terms] OR ("root"[All Fields] AND "resorption"[All Fields]) OR "root resorption"[All Fields]) AND ("orthodontics"[MeSH Terms] OR "orthodontics"[All Fields]) AND aligners[All Fields]
Comments on
The Evidence
Validity: The results of the first study were derived from a case-control study that had 372 patients. The sample size was calculated with a power of 80% and 95% confidence interval. The sample size met the case-control studies estimation of sample size; it was large enough to represent the population. All variables affecting the result were put into consideration including genetic predisposition. The second study did not have a control group for comparison. One limitation of both studies is that they used panoramic and lateral cephalometric radiographs, while conventional intraoral periapical radiographs would be a better way to evaluate orthodontically induced external apical root resorption. Perspective: Clear aligners were thought to cause less root resorption due to the nature of the force that it generates (intermittent), as this force will allow a period of time for the cementum at the root apex to heal during the pause period. On the other hand, the most up-to-date protocols for fixed appliances state that light forces are to be used. This might be the reason why there is no statistically significant difference in orthodontically induced apical root resorption between fixed appliances and the removable aligners (P> .05).
Applicability Clear aligners have multiple advantages over conventional fixed appliances, such as improved esthetics and hygiene. It was thought that patients with short roots might be better treated with clear aligners, as they cause no orthodontically induced external apical root resorption. It is important to clarify that the clear aligners do not reduce the incidence of orthodontically induced external apical root resorption. The results may be useful for the general dentist and orthodontist to help them make clinical decisions on which treatment modality they should use.
Specialty/Discipline (General Dentistry) (Orthodontics)
Keywords Orthodontics, Root resorption, Aligners, Fixed appliance
ID# 3124
Date of submission: 11/21/2016spacer
E-mail Alsalmanh@uthscsa.edu
Author Hala Alsalman, BDS
Co-author(s)
Co-author(s) e-mail
Faculty mentor/Co-author Ravikumar Anthony, BDS, MDS, MS
Faculty mentor/Co-author e-mail Anthonyr@uthscsa.edu
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