Title Insufficient Evidence to Determine if Initial Arch Wire Type Impacts the Rate of Alignment.
Clinical Question In an orthodontic patient with fixed appliances, does the initial arch wire type impact the rate of alignment?
Clinical Bottom Line For an orthodontic patient with fixed appliances, there is insufficient evidence to determine if initial arch wire type impacts the rate of alignment. This is supported by a systematic review which failed to justify a difference in rate of alignment between various arch wire types due to insufficient and low-quality evidence. At this time, more well-designed randomized controlled trials (RCTs) at low risk of bias are necessary to determine if there is a clinical difference in the rate of alignment between different arch wires.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
30064155Wang/2018799 participantsSystematic review of randomized trials
Key resultsThis updated review included 12 RCTs that created a sample size of 799 participants. Six initial arch wire comparisons were assessed using this sample. There was insufficient evidence to determine a difference in rate of alignment between multistrand stainless steel, superelastic nickel-titanium (NiTi), thermoelastic NiTi, and conventional NiTi arch wires; however, one moderate-quality study suggests that coaxial superelastic NiTi can produce greater movement than single-stand superelastic NiTi over a 12-week period.
Evidence Search ((first arch wire) OR (initial arch wire)) AND (fixed appliances) AND (rate of alignment) AND (orthodontic treatment)
Comments on
The Evidence
Wang included RCTs involving an initial arch wire to align teeth with upper, lower, or both, full arch fixed orthodontic appliances. Three studies were determined to be at high risk of bias, three were determined to be at low risk of bias, and three were unclear. Only two studies had sufficient evidence to undertake a meta-analysis. None of the studies reported evidence of root resorption. In the studies that evaluated pain, there were no meaningful differences between the various initial arch wires. More well-designed, high quality research is necessary to determine if there is a clinical difference in the rate of alignment between different arch wires.
Applicability For orthodontists, knowing if a particular initial arch wire type has an impact on the rate of alignment would benefit the orthodontist and patient alike. Although there is insufficient evidence to answer this clinical question at the time, other confounding factors, such as bracket type, slot size, and extractions may play a role, and adverse events, such as root resorption, should be considered. In addition, orthodontists should be aware of expensive arch wires that are marketed as being more efficient, since there has been no proven efficacy between alloys; however, newer alloys, compared to stainless steel, do not have to be changed as often which may offset the higher cost of the arch wire.
Specialty (Orthodontics)
Keywords Orthodontics, Arch Wire Type, Rate of Alignment
ID# 3433
Date of submission 05/15/2020
E-mail millerd8@livemail.uthscsa.edu
Author Dakota Miller
Co-author(s) e-mail
Faculty mentor Dr. Kelly Lemke DDS MS
Faculty mentor e-mail LemkeK@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
None available