American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics | 2019
Optimal force magnitude for bodily orthodontic tooth movement with fixed appliances: A systematic review.
Abstract
INTRODUCTION\nThere is a high degree of uncertainty regarding the appropriate force level that should be applied during orthodontic tooth movement (OTM). As a result, orthodontic treatments may take longer than necessary, leading to unwanted side effects. This review aimed to identify an optimal force range with the rate of OTM as the primary outcome. External apical root resorption and pain were evaluated as secondary outcomes, and the influence of growth was examined.\n\n\nMETHODS\nFive electronic databases were searched (MEDLINE [via PubMed], Embase [via OVID], Cochrane Library, CINAHL, and Web of Science) with no publication date or language restrictions. Inclusion eligibility screening, quality assessment, and data extraction were performed by 3 investigators. Each retrieved record was assessed by 2 observers independently. Only randomized controlled trials and randomized split-mouth studies were included.\n\n\nRESULTS\nA total of 12 articles satisfied the inclusion criteria-two randomized controlled trials and 10 randomized split-mouth studies. Only 1 study showed a low risk of bias, whereas the remaining 11 were unclear. The qualitative analysis showed that forces between 50\xa0cN and 250\xa0cN produced a similar OTM rate; forces\xa0>250\xa0cN yielded a slightly higher rate but were accompanied by adverse effects. Because of considerable heterogeneity in methodology, clinical diversity with varying forces between 18\xa0cN and 360\xa0cN, and poor statistical reporting, a meta-analysis was deemed inappropriate.\n\n\nCONCLUSIONS\nForces between 50\xa0cN and 100\xa0cN seem optimal for OTM, patient comfort and potentially exhibit fewer side effects. Nevertheless, careful data interpretation is necessary because of the lack of strong evidence. Protocol registration: PROSPERO CRD42016039985.