Canine and molar movement, rotation and tipping by NiTi coils versus elastomeric chains in first maxillary premolar extraction orthodontic adolescents: A randomized split-mouth study.

PURPOSE: The primary objective was to compare canine and molar movement between NiTi coil and elastomeric chains. The secondary objective was to compare the side effects of these techniques (rotation and tipping). MATERIALS AND METHODS: This single-blind randomized split-mouth clinical trial was done prospectively. Healthy patients who needed extraction of the first maxillary premolars and did not require anchorage reinforcement techniques for orthodontic treatment were included. Following initial levelling and alignment a dental cast and panoramic radiographs were taken (pre-space closure documents) and canine retraction was done using elastomeric chains on one side and NiTi closed coil spring on the other side. After four months, the same documents were taken and movement (mm), as well as rotation (degree) and tipping (degree) of canines and first molars, were calculated by comparison of pre and post space closure documents by a blinded examiner. Data were analysed by independent samples t-test and Mann-Whitney U test with a significance level of 0.0125. RESULTS: Overall 20 patients completed the study. The average canine movement was 3.88 and 5.45mm (distal movement) in elastomeric chains and NiTi coil groups, respectively (P=0.001). For molars, the movement was 1.20 and 1.15mm (mesial movement), respectively (P=0.529). The mean rotation of the canine in elastomeric chains and NiTi coil groups were 4.50° and 7.43° (mesiobuccal rotation), respectively (P=0.006). For the molars, the mean rotation was 0.23° and 1.90° (mesiolingual rotation), respectively (P=0.307). Average tipping of the canine in elastomeric chains and NiTi coil groups were 4.52° and 7.55° (distal tipping), respectively (P=0.011). For the molars, the numbers were 1.45° and 4.80° (mesial tipping), respectively (P=0.028). CONCLUSION: Canine retraction by NiTi coil springs is faster compared to elastomeric powerchains with the cost of more canine tipping and rotation and more molar tipping. No significant difference was found in molar movement, rotation and tipping between the two techniques.

Effect of gingival biotype on orthodontic treatment-inducedperiodontal complications: A systematic review.

Background: It is crucial to maintain periodontal health in patients undergoing orthodontic treatment. Biotype is a critical factor to be considered in this regard. This systematic review investigated the scientific evidence on the relationship between gingival biotype and marginal periodontal alterations induced by orthodontic interventions. Methods: An electronic search was conducted for pertinent studies in three databases: PubMed, Scopus, and Cochrane up to August 1, 2019 based on a detailed protocol according to the PRISMA statement. The authors also completed a hand search in six dental journals and the bibliographic lists of the relevant studies. Results: Of 1512 citations retrieved through the electronic search, 602 were duplicate entries. By evaluating titles, abstracts, and full texts, eight articles conformed to the inclusion criteria; however, no relevant studies were found through hand searching. The evidence suggested that recession was inversely related with the thickness of the facial margin. These findings were more evident in proclined teeth and patients using fixed appliances. Conclusion: The existing evidence suggests that orthodontic therapy might result in mild detrimental effects on the periodontium, especially in patients with thin biotype. However, due to the limited investigations and their inconsistent methodology, further well-designed prospective studies are necessary.