Alignment efficiency of coaxial tubular superelastic nickel-titanium vs single-stranded superelastic nickel-titanium in relieving mandibular anterior crowding in extraction cases: A single-centre randomized controlled clinical trial

Initial arch wires used in orthodontic treatment with fixed appliances

BACKGROUND

Initial arch wires are the first arch wires inserted into fixed appliance at the beginning of orthodontic treatment. With a number of different types of orthodontic arch wires available for initial tooth alignment, it is important to understand which are most efficient and which cause the least amount of root resorption and pain during the initial aligning stage of treatment. This is the third update of a Cochrane review first published in 2010.

OBJECTIVES

To assess the effects of initial arch wires for the alignment of teeth with fixed orthodontic braces, in terms of the rate of tooth alignment, amount of root resorption accompanying tooth movement, and intensity of pain experienced by patients during the initial alignment stage of treatment.

SEARCH METHODS

We searched Cochrane Oral Health's Trials Register, CENTRAL, MEDLINE, Embase, and two ongoing trials registries on 4 July 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of different initial arch wires used to align teeth with fixed orthodontic braces. We included people with full-arch fixed orthodontic appliances on the upper arch, lower arch, or both arches.

DATA COLLECTION AND ANALYSIS

Two independent review authors were responsible for study selection, data extraction, and assessment of risk of bias in included studies. We contacted corresponding authors of included studies to obtain missing information. We resolved disagreements by discussion between the review authors. Our main outcomes were alignment rate (movement of teeth in mm), root resorption, time to alignment, and intensity of pain measured on a 100-mm visual analogue scale (VAS). We pooled data from studies with similar interventions and outcomes using random-effects models. We reported mean differences (MDs) with 95% confidence intervals (CIs) for continuous data, risk ratios (RRs) with 95% CIs for dichotomous data, and alignment rate ratios with 95% CIs for time-to-event data. Two independent review authors assessed the certainty of evidence. We resolved disagreements by discussion between the review authors.

MAIN RESULTS

We included 29 RCTs with 1915 participants (2581 arches) in this review. Studies were generally small (sample sizes ranged from 14 to 200 participants). Duration of follow-up varied between three days and six months. Eleven studies received funding, six received no funding, and 12 provided no information about funding sources. We judged eight studies at high risk of bias, nine at low risk, and 12 at unclear risk. We grouped the studies into six main comparisons. Multistrand stainless steel wires versus wires composed of other materials Six studies with 409 participants (545 arches) evaluated multistrand stainless steel (StSt) wires versus wires composed of other materials. We are very uncertain about the effect of multistrand StSt wires versus other wires on alignment rate (4 studies, 281 participants, 417 arches; very low-certainty evidence). There may be little to no difference between multistrand StSt wires and other wires in terms of intensity of pain (MD -2.68 mm, 95% CI -6.75 to 1.38; 2 studies, 127 participants, 127 arches; low-certainty evidence). Conventional nickel-titanium wires versus superelastic nickel-titanium wires Four studies with 266 participants (274 arches) evaluated conventional nickel-titanium (NiTi) wires versus superelastic NiTi wires. There may be little to no difference between the different wire types in terms of alignment rate (124 participants, 124 arches, 2 studies; low-certainty evidence) and intensity of pain (MD -0.29 mm, 95% CI -1.10 to 0.52; 2 studies, 142 participants, 150 arches; low-certainty evidence). Conventional nickel-titanium wires versus thermoelastic copper-nickel-titanium wires Three studies with 210 participants (210 arches) evaluated conventional Ni-Ti versus thermoelastic copper-nickel-titanium (CuNiTi) wires. We are very uncertain about the effects of the different arch wires on alignment rate (1 study, 66 participants, 66 arches; very low-certainty evidence). There may be little to no difference between conventional NiTi wires and thermoelastic CuNiTi wires in terms of time to alignment (alignment rate ratio 1.30, 95% CI 0.68 to 2.50; 1 study, 60 participants, 60 arches; low-certainty evidence). Superelastic nickel-titanium wires versus thermoelastic nickel-titanium wires Twelve studies with 703 participants (936 arches) evaluated superelastic NiTi versus thermoelastic NiTi wires. There may be little to no difference between superelastic NiTi wires and thermoelastic NiTi wires in alignment rate at four weeks (MD -0.28 mm, 95% CI 0.62 to 0.06; 5 studies, 183 participants, 183 arches; low-certainty evidence). We are very uncertain about the effects of the different wires on root resorption (2 studies, 52 participants, 312 teeth; very low-certainty evidence). Superelastic NiTi wires compared with thermoelastic NiTi wires may result in a slight increase in time to alignment (MD 0.5 months, 95% CI 0.21 to 0.79; 1 study, 32 participants, 32 arches; low-certainty evidence) but are probably associated with a slight increase in intensity of pain (MD 6.96 mm, 95% CI 1.82 to 12.10; 3 studies, 94 participants, 138 arches, moderate-certainty evidence). Single-strand superelastic nickel-titanium wires versus coaxial superelastic nickel-titanium wires Three studies with 104 participants (104 arches) evaluated single-strand superelastic NiTi versus coaxial superelastic NiTi wires. Use of single-strand superelastic NiTi wires compared with coaxial superelastic NiTi wires probably results in a slight reduction in alignment rate at four weeks (MD -2.64 mm, 95% CI -4.61 to -0.67; 2 studies, 64 participants, 64 arches, moderate-certainty evidence). Different sizes of nickel-titanium wires Two studies with 149 participants (232 arches) compared different types of NiTi wires. There may be little to no difference between different sizes of NiTi wires in terms of pain (low-certainty evidence).

AUTHORS' CONCLUSIONS

Superelastic NiTi wires probably produce slightly more pain after one day than thermoelastic NiTi wires, and single-strand superelastic NiTi wires probably have a lower alignment rate over four weeks compared with coaxial superelastic NiTi wires. All other evidence on alignment rate, root resorption, time to alignment, and pain is of low or very low certainty in all comparisons. Therefore, there is insufficient evidence to determine whether any particular arch wire material or size is superior to any other. The findings of this review are imprecise and unreliable; well-designed larger studies are needed to give better estimates of the benefits and harms of different arch wires. Orthodontists should exercise caution when interpreting the findings of this review and be prepared to adapt their treatment plans based on individual patient needs.

Effectiveness of tubular coaxial nickel-titanium and copper nickel-titanium orthodontic aligning archwires: A randomized clinical trial

BACKGROUND

This study aimed to compare tubular coaxial-NiTi and copper-NiTi orthodontic aligning archwires in terms of teeth alignment, patients' pain perception, and root resorption.

SUBJECTS AND METHODS

Orthodontic patients aged 12 years or older, having Little's irregularity index (LII) of 5-9mm were randomly allocated to either the copper-NiTi group or tubular coaxial-NiTi group with a 1:1 allocation ratio. The archwire sequence was 0.014-inch followed by 0.018-inch for the copper-NiTi group and 0.016-inch followed by 0.018-inch for the tubular coaxial-NiTi group. Each archwire was left in place for eight weeks before progressing to the next size. Good quality impression for the lower arch before treatment (T0) and thereafter every 4 weeks up to 16 weeks was taken to measure LII. Evaluation of pain perception was performed using a visual analog scale (VAS) during the first week following each archwire insertion. Assessment of root resorption was undertaken at T0 and after 16 weeks by taking periapical radiographs for mandibular central incisors using the long cone paralleling technique.

RESULTS

A total of 33 patients were randomized and selected for participation. Of those, 31 patients with a mean age of 15.45±2.22 who completed the trial were included in the analyses (15 patients in the copper-NiTi group and 16 patients in the tubular coaxial-NiTi group). In both groups, the irregularity index significantly decreased after 16 weeks of treatment with an overall reduction of 5.22mm for the copper-NiTi group and 6.03mm for the tubular coaxial-NiTi group. However, the difference between the two groups was not statistically significant. Likewise, pain perception and root resorption were not significantly different between the two study groups.

CONCLUSIONS

Both copper-NiTi and tubular coaxial-NiTi archwires were equally effective in terms of teeth alignment, patients' pain perception, and root resorption. Consideration could be given to the cost and clinician preference when selecting an initial archwire.

REGISTRATION

the trial was registered in ClinicalTrials.gov on 26/05/2022 with a registration ID: NCT05391542, https://clinicaltrials.gov/ct2/show/NCT05391542.

The scientific evidence for pre-adjusted edgewise attachments and mechanics

Introduction Fixed orthodontic appliance systems continue to evolve with a wealth of evidence emerging to underpin these refinements.Aims To present the evidence from comparative prospective research informing the selection of fixed appliance design and mechanics.Design Detailed literature review.Materials and methods An electronic search to identify randomised controlled trials and clinical controlled trials was undertaken using pre-defined search terms.Results Based on high-level evidence, no one bracket system has been proven superior in terms of efficiency or outcome. Similarly, a clear advantage associated with one wire type or dimension has not been shown. The effect of lacebacks in terms of anchorage management appears to be limited, while elastomeric chain and nickel titanium closing coils are associated with similar rates of space closure.Discussion A wealth of high-quality recent evidence to support the selection of fixed appliance attachments, archwires and auxiliaries, including lacebacks and space closing mechanics, was identified.Conclusions There has been a considerable increase in the amount of high-quality evidence informing the choice of pre-adjusted edgewise mechanics in recent years. This information can be used to make evidence-based decisions in the selection and manipulation of fixed appliances during daily practice.

Duration of tooth alignment with fixed appliances: A systematic review and meta-analysis

INTRODUCTION

A key goal of orthodontic treatment with fixed appliances is alignment of the dentition, and this remains a commonly selected outcome in clinical studies investigating orthodontic tooth movement. This systematic review has evaluated treatment duration to achieve alignment of the mandibular dentition using fixed appliances.

METHODS

Systematic literature searches without restrictions were undertaken in 9 databases for randomized clinical trials (RCTs) assessing duration and rate of tooth alignment using fixed appliances with or without treatment adjuncts published up to January 2021. After duplicate study selection, data extraction, and risk of bias assessment according to Cochrane, random-effects meta-analyses of aggregate data, and individual patient data were conducted.

RESULTS

Thirty-five trials were included with 2258 participants (39% male; mean age 17.8 years), giving a pooled duration to achieve whole-arch alignment of the mandibular dentition of 263.0 days (4 trials; 95% confidence interval [CI], 186.7-339.4 days) and incisor alignment in the mandibular arch of 100.7 days (9 trials; 95% CI, 84.1-117.4 days). Surgical-assisted orthodontics was associated with reduced duration of incisor alignment: mean difference of 44.3 days less (4 trials; 95% CI, 20.0-68.9 days; P <0.001; high quality of evidence), whereas subgroup and meta-regression analyses indicated significant effects of baseline crowding and premolar extractions. Individual patient data analysis from 3 RCTs indicated that for each additional participant age year, whole-arch alignment of the mandibular dentition took 13.7 days longer (3 trials; 95% CI, 7.7-17.7 days; P <0.001) and for each additional mm of irregularity, 17.5 days more were needed (2 trials; 95% CI, 9.8-25.2 days; P <0.001).

CONCLUSIONS

Patient and treatment-related characteristics can significantly affect the duration of tooth alignment and should be taken into account both clinically and when designing trial outcomes. Future research studies investigating rates of orthodontic tooth alignment would benefit from adequate sample sizes and a more consistent methodology in outcome assessment. Data in this systematic review provides a basis for appropriate trial design for future RCTs investigating the rate of orthodontic tooth alignment with fixed appliances.

Tooth alignment and pain experience with A-NiTi versus Cu-NiTi: a randomized clinical trial

Background

Nickel-titanium (NiTi) archwires are routinely used for initial leveling and alignment of teeth in orthodontic treatment. This study aimed to clinically compare the level of pain and tooth alignment in orthodontic treatment with A-NiTi versus Cu-NiTi archwires.

Methods

In this parallel randomized clinical trial, 88 orthodontic patients (12–25 years) with an irregularity index > 2 mm in the anterior site of the lower dental arch who required non-extraction orthodontic treatment of the lower arch were randomized into two age- and sex-matched groups (n = 44) for treatment with A-NiTi and Cu-NiTi initial archwires. Each archwire was used for 6 weeks. After 6 weeks, the irregularity index was measured, and the level of pain was scored using the Modified McGill pain questionnaire (MPQ) and visual analog scale (VAS) according to the time of onset and duration of pain, and analgesic intake. Data were analyzed by paired t test, independent samples t test, and Chi-square test (P < 0.05).

Results

The irregularity index significantly decreased in both groups after 6 weeks of treatment (P < 0.001). However, the difference in this respect was not significant between the two groups (P > 0.05). Pain perception (P = 0.487), duration of pain (P = 0.546), and analgesic intake (P = 0.102) were not significantly different between the two groups either.

Conclusion

Both A-NiTi and Cu-NiTi archwires are equally effective for tooth alignment in the anterior site of the lower dental arch and have no significant difference with regard to the level of pain experienced by patients.

Trial registration number: IRCT20190705044102N1 and Name of the registry: Iranian registry of clinical trials (https://irct.ir/) Date of registration: September, 26, 2019