Pain and discomfort experienced after placement of a conventional or a superelastic NiTi aligning archwire. A randomized clinical trial. Clinical comparison and performance perspective of three aligning arch wires. The pain and discomfort experienced during orthodontic treatment: a randomized controlled clinical trial of two initial aligning arch wires. Multiflex versus superelastic: a randomized clinical trial of the tooth alignment ability of initial arch wires. Alleviation of mandibular anterior crowding with copper-nickel-titanium vs nickel-titanium wires: a double-blind randomized control trial. Alignment efficiency of superelastic coaxial nickel-titanium vs superelastic single-stranded nickel-titanium in relieving mandibular anterior crowding: a randomized controlled prospective study. Efficiency of multi-strand steel, superelastic Ni-Ti and ion-implanted Ni-Ti archwires for initial alignment. Pain perception following first orthodontic archwire placement--thermoelastic vs superelastic alloys: a randomized controlled trial. A 3-year follow-up study of various types of orthodontic canine-to-canine retainers.
Two nickel-titanium arch-wire types commonly used for initial tooth alignment were compared with regard to the pain/discomfort patients experience during the initial phase of tooth movement. The two arch wires used were a superelastic nickel-titanium alloy, 0.014 inch Sentalloy, Light (GAC International Inc. Central Islip, NY, USA) and a 0.014 inch Nitinol (Unitek, Monrovia, CA, USA), a conventional nickel-titanium aligning archwire. One hundred and twenty-eight consecutive patients attending an orthodontic university clinic and 2 private practices for routine placement of a fixed appliance were randomly assigned one of these 2 initial arch wires. Assessments of pain/discomfort were made daily by means of a 100 mm visual analog scale (VAS) over the first 7-day period after bonding. On the first day, recordings were made every hour for the first 11 hours. The results showed that the level of discomfort increased continuously every hour after the insertion of either a Sentalloy or a Nitinol as first arch wires, with a peak in the first night, remaining high on the second day and decreasing thereafter to baseline level after 7 days. During the first 10 hours it was apparent that the pain/discomfort experienced after placement of a Sentalloy was less than that found with the Nitinol archwire, although a significant difference could be found at 4 hours only. No significant gender-specific differences were found in either archwire group. A significant difference between the upper and lower dental arches was observed during the first 11 hours after placement of either a Sentalloy or a Nitinol arch wire, with the lower arch having the higher pain experience. To clinically evaluate three commonly used orthodontic tooth aligning arch wires: 016 x 022 inch active martensitic medium force nickel titanium, 016 x 022 inch graded force active martensitic nickel titanium, and 0.0155 inch multistrand stainless steel.
                A prospective randomized clinical trial.
                Measured serial study casts of dental arches for 112 assigned arch wires from 56 consecutive patients. Analysis based on completed records for 98 arch wires and 51 patients.
                A consecutive sample of 56 patients requiring both upper and lower fixed appliance therapy were randomly allocated two different arch wires from a possible three under trial. Good quality impressions were taken of the dental arches at the designated serial stages of alignment (start, T0; 4 weeks, T4; 8 weeks, T8). The resultant casts were measured on a Reflex Microscope to record the change in individual tooth alignment both in three and two dimensions (horizontal plane only).
                The measurement error was within acceptable limits (range, 0.05 to 0.09 mm) and showed no significant bias. ANOVA statistical models were fitted to the data to adjust for a number of variables. No significant difference in aligning capability (p > 0.05), in either two or three dimensions, was demonstrated between the three arch wires in the trial.
                Heat activated nickel titanium arch wires failed to demonstrate a better performance than the cheaper multistrand stainless steel wires in this randomized clinical trial. The failure to demonstrate in vivo superiority at the clinical level may be due to the confounding effects of large variations in individual metabolic response. Alternatively, it may be that in routine clinical practice NiTi-type wires are not sufficiently deformed to allow their full superelastic properties to come in to play during initial alignment. 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. Two arch wires commonly used for initial tooth alignment were compared with regard to their clinical effectiveness. The two arch wires tested were 0.0155-inch diameter multiple-stranded stainless steel wire (Dentaflex, Dentaurium, Optident, Yorkshire, England) and 0.014-inch diameter nickel-titanium alloy wire (NiTi, ORMCO Co., Monrovia, Calif.). Consecutive patients attending an orthodontic clinic for routine placement of a fixed appliance were randomly assigned one of these two initial arch wires. Good quality alginate impressions of the appropriate dental arch were taken before arch wire placement and also at the subsequent appointment, which was, on average, 6 weeks later. Seventy-four arches were used in this study. The degree of tooth alignment achieved for each wire type was compared with a Reflex Microscope (Reflex Measurement Ltd., Butleigh, England) to make detailed measurements on the resultant casts. The degree of initial alignment achieved with the two wires was similar over this 6-week period. However, some differences were found for the lower labial segment where the interbracket span is usually reduced and where the superelastic nickel-titanium wire was found to give improved alignment. No threshold of crowding was found where one arch wire performed better than the other. The purpose of this study was to investigate the efficiency of copper-nickel-titanium (CuNiTi) vs nickel-titanium (NiTi) archwires in resolving crowding of the anterior mandibular dentition.
                Sixty patients were included in this single-center, single-operator, double-blind randomized trial. All patients were bonded with the In Ovation-R self-ligating bracket (GAC, Central Islip, NY) with a 0.022-in slot, and the amount of crowding of the mandibular anterior dentition was assessed by using the irregularity index. The patients were randomly allocated into 2 groups of 30 patients, each receiving a 0.016-in CuNiTi 35 degrees C (Ormco, Glendora, Calif) or a 0.016-in NiTi (ModernArch, Wyomissing, Pa) wire. The type of wire selected for each patient was not disclosed to the provider or the patient. The date that each patient received a wire was recorded, and all patients were followed monthly for a maximum of 6 months. Demographic and clinical characteristics between the 2 wire groups were compared with the t test or the chi-square test and the Fisher exact test. Time to resolve crowding was explored with statistical methods for survival analysis, and alignment rate ratios for wire type and crowding level were calculated with Cox proportional hazards multivariate modeling.
                The type of wire (CuNiTi vs NiTi) had no significant effect on crowding alleviation (129.4 vs 121.4 days; hazard ratio, 1.3; P >0.05). Severe crowding (>5 on the irregularity index) showed a significantly higher probability of crowding alleviation duration relative to dental arches with a score of <5 (138.5 vs 113.1 days; hazard ratio, 2.2; P=0.02).
                The difference of the loading pattern of wires in laboratory and clinical conditions might effectively eliminate the laboratory-derived advantage of CuNiTi wires. To clinically evaluate the alignment efficiency of 0.016-inch coaxial superelastic nickel-titanium (NiTi) and 0.016-inch superelastic NiTi in the lower anterior region over a period of 12 weeks. Materials and
                A sample of 24 patients requiring lower anterior alignment were included in this single-center, single-operator, double-blind clinical trial and were randomly allocated into two groups of 12 patients. The type of wire selected for each patient was not disclosed to the provider or to the patient. Comparison of pretreatment characteristics of the archwire groups revealed no discrimination between two samples, thus verifying the random allocation of the intervention. An initial alginate impression of the lower arch was followed by impressions at 4-, 8-, and 12-week intervals. Casts were measured using the coordinate measuring machine to denote the degree of alignment. Duplicate readings of the cast series were taken to assess measurement variation.
                A statistically significant difference (P < .05) in the mean values of tooth movement demonstrated the superior aligning efficiency of coaxial superelastic NiTi over single-stranded superelastic NiTi in relieving lower anterior crowding. The measurement error recorded was within acceptable limits, with range values within 95% limits of agreement.
                Coaxial superelastic NiTi wire proved superior to single-stranded NiTi in its efficiency in relieving lower anterior crowding over a 12-week period. In a clinical trial involving 155 dental arches with irregularity > 5 mm, the rate of alignment was used to compare the alignment efficiency of 16 mil superelastic Ni-Ti versus 17.5 mil triple-stranded steel archwires, and to determine whether ion implantation of the Ni-Ti wire improved its performance. Subjects were randomly assigned to archwire types; both 18 and 22 slot edgewise appliances were employed. Pre-treatment equivalence of the experimental groups was verified. Anterior irregularity was determined monthly (using Little's irregularity index) until it decreased below 2 mm, and the elastomeric ligatures were replaced at each appointment. Effective tooth movement occurred with each of the archwire types. There were no significant differences among wires, but the rate of alignment was significantly faster in the lower arch for subjects with the 22 slot appliance. Orthodontic thermoelastic archwires produce lighter and more biologic forces than superelastic archwires and could therefore offer the possibility of reducing initial orthodontic pain. Nevertheless, evidence concerning this issue is scarce. The aim of this study was to compare pain perception following first archwire placement in patients with thermal heat-activated (HANT) and superelastic (SE) nickel-titanium archwires.
                Thirty subjects (11 males, 19 females; range, 11 to 26 years of age) were recruited. Metal brackets were bonded in the maxillary or mandibular arch. Round 0.016-inch HANT or 0.016-inch SE archwires were randomly placed and tied with elastic ligatures. Each patient was invited to score tooth pain for 7 days at different time points (8:00, 12:00, 16:00, 20:00, and 24:00) using the visual analog scale (VAS).
                In both groups, pain was highest at day 2 and lowest at day 7. Patients with HANT archwires had significantly lower VAS scores (P < .005) at days 2, 3, and 4 than subjects with SE archwires. This was also the case after adjusting for analgesic consumption, sports practicing, overlapping pain of different origin, and the concomitance of stressful events. The frequency of analgesic consumption was higher in the SE than in HANT group at day 3 (P < .05). No differences in pain perception were found between time points, nor was any correlation found between dental crowding and pain. No difference in pain perception was found between the maxillary and mandibular dental arches.
                Initial orthodontic pain is reduced when using HANT orthodontic archwires. The present study was performed to test the tendency for plaque and calculus build-up along the wire of different types of bonded orthodontic canine-to-canine retainers, whether the presence of such retainers causes any damage to the teeth involved, the failure rate of the retainers, and any changes in incisor alignment during a 3-year period of retention. The four test groups received either retainers made of thick plain wire bonded only to the canines (n = 11); thick spiral wire bonded only to the canines (n = 13); thin, flexible spiral wire bonded to each tooth (n = 11); or removable retainers (n = 14). Accumulation of plaque and calculus along the gingival margin, gingival inflammation and probing attachment level were scored in lingual areas from canine to canine at the time of fixed appliance removal and again 3 years after retainer insertion. Incisor irregularity was measured on plaster models made at the same time periods. Accumulation of plaque and calculus and development of caries along the wire were scored at follow-up. Retainer failures were recorded whenever they occurred. The results revealed no intergroup differences in changes between baseline and follow-up examinations or status along the retainer wire for any of the variables. Gingival inflammation and plaque accumulation were scored less frequently after 3 years in retention than at the time of debonding. No signs of caries were seen adjacent to the wire. Failures were observed of one, four and three of the fixed retainer types, respectively. These patients showed a greater increase in incisor irregularity than the other patients.
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.