There is no reliable evidence from the trials included in this review that any specific initial arch wire material is better or worse than another with regard to speed of alignment or pain. There is no evidence at all about the effect of initial arch wire materials on the important adverse effect of root resorption. Further well-designed and conducted, adequately-powered, RCTs are required to determine whether the performance of initial arch wire materials as demonstrated in the laboratory, makes a clinically important difference to the alignment of teeth in the initial stage of orthodontic treatment in patients.
The pain and discomfort experienced during orthodontic treatment: a randomized controlled clinical trial of two initial aligning arch wires.
A randomized controlled clinical trial was performed to compare the nature, prevalence, intensity, and duration of pain related to the use of a relatively recently developed superelastic arch wire and a more traditional multistranded steel arch wire. Other factors likely to influence the pain experience were also investigated. Forty-three subjects participated in the study, the pain response being assessed by each of the visual analogue scales, the questionnaires, and an analgesic consumption record. In 18 of the 43 subjects a standardized preliminary dental extraction procedure was used as a control. Subsequent to the random allocation of an initial arch wire in 43 patients, 22 of them underwent a second arch wire in the opposing arch, the wire again being determined by random allocation. It was found that the prevalence, intensity, and duration of pain after the insertion of the two types of wire was similar but much greater than in the postextraction control phase. The pain score peaked on the morning after the placement of the arch wire, lasting typically for 5 to 6 days. The pain and discomfort experienced after the insertion of the second arch wire was similar to that of the first, no conditioning response being evident. Overall a diurnal variation was found with a tendency to an increase in pain in the evenings and nights, although this did not greatly affect sleep. The pain response was found to be highly and consistently subjective, not related to the dental arch, crowding, sex, or social class; however, a statistically significant association was found between the age and the pain experienced.