Self-ligating brackets in orthodontics. A systematic review

The effect of bracket ligation on the periodontal status of adolescents undergoing orthodontic treatment. A systematic review and meta-analysis

INTRODUCTION/OBJECTIVES

This systematic review aimed to critically appraise the evidence regarding the effect of bracket ligation type on the periodontal conditions of adolescents undergoing orthodontic treatment.

DATA

Search terms included randomized controlled trial (RCTs), controlled clinical trials, ligation, bracket, periodontal, inflammation. Risk of bias assessment was made using the Cochrane risk of bias tool and the quality of evidence was assessed with GRADE.

SOURCES

Electronic Database search of published and unpublished literature was performed without language restriction in May 25, 2016 (MEDLINE via Pubmed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Clinical Trials.gov and National Research Register).

STUDY SELECTION

Of 140 articles initially retrieved, 8 were eligible for inclusion in the systematic review, while 4 RCTs with unclear risk of bias were included in the quantitative synthesis, all comparing self-ligating to conventional steel ligated brackets. Random effects meta-analyses were implemented. At 4-6 weeks after bracket placement there was no evidence to support the use of either type of bracket for achieving improved plaque- (PI) and gingival index (GI). At 3-6 months, there was scarce evidence of greater PI increase for conventional brackets. GI and pocket depth pooled estimates did not reveal significant differences between the two systems. The quality of the evidence was moderate according to GRADE for all outcomes.

CONCLUSIONS

Overall, non-significant differences on the periodontal status of adolescents undergoing orthodontic treatment with either conventional or self-ligating brackets were detected.

CLINICAL SIGNIFICANCE

The periodontal status of adolescents undergoing orthodontic treatment is of considerable importance. The synthesis of the available evidence on oral hygiene related factors will provide insights to best clinical practice during the course of orthodontic treatment.

Cone Beam Computed Tomography-based Evaluation of the Anterior Teeth Position Changes obtained by Passive Self-ligating Brackets

AIM

The objective of this study was to evaluate the anterior teeth position changes obtained by passive self-ligating brackets using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

Twenty patients with a mean age of 16.5 years, class I malocclusion, constricted maxillary arch, and teeth crowding above 5 mm were enrolled in this study, and treated by passive orthodontic self-ligating brackets. A sequence of stainless steel thermoset wire was implemented with ending wire of 0.019" × 0.025". The CBCT and dental casts were obtained prior to the installation of orthodontic appliances (T1), and 30 days after rectangular steel wire 0.019" × 0.025" installation (T2). The measurements in CBCT were performed with the Anatomage software, and the dental casts were evaluated with a digital caliper rule with an accuracy of 0.01 mm.

RESULTS

The CBCT data demonstrated mean buccal inclination of the upper and lower central incisors ranging from 6.55° to 7.24° respectively. The upper and lower lateral incisors ranged from 4.90° to 8.72° respectively. The lower canines showed an average increase of 3.88° in the buccal inclination and 1.96 mm in the transverse intercuspal distance. The upper canines showed a negative inclination with mean average of -0.36°, and an average increase of 0.82 mm in the transverse distance, with negative correlation with the initial crowding.

CONCLUSION

Treatment with passive self-ligating brackets without obtaining spaces increases buccal inclination of the upper and lower incisors with no correlation with the amount of initial teeth crowding. The intercanine distance tends to a small increase showing different inclinations between the arches.

CLINICAL SIGNIFICANCE

When taking into account the self-ligating brackets, the amount of initial dental crowding is not a limitation factor that could increase the buccal inclination of the anterior teeth.

Archwire diameter effect on tooth alignment with different bracket-archwire combinations

INTRODUCTION

Our objective was to evaluate the effect of the diameter of the archwire on tooth alignment with different bracket-archwire combinations.

METHODS

The materials included 2 categories of orthodontic brackets (1) conventional ligating brackets (Victory Series [3M Unitek, Monrovia, Calif], Mini-Taurus [Rocky Mountain Orthodontics, Denver, Colo], and Synergy [Rocky Mountain Orthodontics]) and (2) self-ligating brackets (SmartClip [3M Unitek], a passive self-ligating bracket; Time3 [American Orthodontics, Sheboygan, Wis], an active self-ligating bracket; and SPEED [Strite Industries, Cambridge, Ontario, Canada], an active self-ligating bracket). All brackets had a nominal 0.022-in slot size. The brackets were combined with Therma-Ti 0.014-in and Therma-Ti 0.016-in titanium memory archwires (American Orthodontics). The archwires were tied to the conventional brackets with both stainless steel ligatures (0.010 in) and elastomeric rings. Each bracket-archwire combination was tested 20 times with the orthodontic measurement and simulation system built in a temperature-controlled chamber where the temperature was kept at 37°C (±1°C) during testing. The malocclusion simulated in the study represented a maxillary central incisor displaced 2 mm gingivally (x-axis) and 2 mm labially (z-axis).

RESULTS

The incisogingival corrections achieved by the 0.014-in archwire combined with the brackets used ranged from 40% to 95%; the corrections by the 0.016-in wire were 55% to 95%. The labiolingual corrections achieved by the 0.014-in archwire combined with the brackets used ranged from 10% to 100%, and the corrections of the 0.016-in archwires ranged from 15% to 100%.

CONCLUSIONS

Increasing the diameter from 0.014 to 0.016 in increased the correction achieved by up to 15% in certain bracket-archwire combinations, but it decreased the correction by up to 25% in other combinations.

Prediction of pain in orthodontic patients based on preoperative pain assessment

AIM

To investigate whether pretreatment assessment of experimental pain can predict the level of pain after archwire placement.

METHODS

One hundred and twenty-one general university students seeking orthodontic treatment were enrolled in this study. A cold pressor test was performed to estimate the pain tolerance of subjects before treatment. Self-reported pain intensity was calculated using a 10 cm visual analog scale during the 7 days after treatment. The relationship between pain tolerance and orthodontic pain was analyzed using Spearman's correlation analysis.

RESULTS

The maximum mean level of pain intensity occurred at 24 hours after bonding (53.31±16.13) and fell to normal levels at day 7. Spearman's correlation analysis found a moderate positive association between preoperative pain tolerance and self-reported pain after archwire placement (P<0.01). There was no significant difference in pain intensity between male and female patients at any time point (P>0.05).

CONCLUSION

A simple and noninvasive preoperative sensory test (the cold pressor test) was useful in predicting the risk of developing unbearable pain in patients after archwire placement. Self-reported pain after archwire placement decreased as individual pain tolerance increased.

[Incisor repositioning: a new approach in orthodontics]

Lower incisors axis has a "key" position in different cephalometric analysis. However, several critics are directed towards the cephalometric profile and cephalometric landmarks (point, line and angle). The published norms and the cephalometric standards recommended for the optimal positioning of incisors could only be used as general clinical guidelines. Incisor repositioning to achieve optimal facial aesthetics requires taking into consideration the hard and soft tissues of the face, the profile, the muscular dynamics as well as the facial growth. In this work, we propose a new approach of incisor repositioning taking into account the variability of periodontal, functional and aesthetic factors.

Canine retraction and anchorage loss self-ligating versus conventional brackets: a systematic review and meta-analysis

Background

The purpose of this systematic review is to identify and review the orthodontic literature with regards to assessing possible differences in canine retraction rate and the amount of antero-posterior anchorage (AP) loss during maxillary canine retraction, using conventional brackets (CBs) and self-ligating brackets (SLBs).

Methods

An electronic search without time or language restrictions was undertake in September 2014 in the following electronic databases: The Cochrane Oral Health Group’s Trials Register, CENTRAL, MEDLINE via OVID, EMBASE via OVID, Web of science. We also searched the reference lists of relevant articles. Quality assessment of the included articles was performed. Two of the authors were responsible for study selection, validity assessment and data extraction.

Results

Six studies met the inclusion criteria, including 2 randomized controlled trials and 4 control clinical studies. One was assessed as being at low risk of bias. Five trials were assessed as being at moderate risk of bias. The meta-analysis from 6 eligible studies showed that no statistically significant difference was observed between the 2 groups in the rate of canine retraction and loss of antero-posterior anchorage of the molars.

Conclusion

There is some evidence from this review that both brackets showed the same rate of canine retraction and loss of antero-posterior anchorage of the molars. The results of the present systematic review should be viewed with caution due to the presence of uncontrolled interpreted factors in the included studies. Further well-designed and conducted randomized controlled trials are required, to facilitate comparisons of the results.

Evaluation of stiffness and plastic deformation of active ceramic self-ligating bracket clips after repetitive opening and closure movements

OBJECTIVE

The aim of this study was to assess whether repetitive opening and closure of self-ligating bracket clips can cause plastic deformation of the clip.

METHODS

Three types of active/interactive ceramic self-ligating brackets (n = 20) were tested: In-Ovation C, Quicklear and WOW. A standardized controlled device performed 500 cycles of opening and closure movements of the bracket clip with proper instruments and techniques adapted as recommended by the manufacturer of each bracket type. Two tensile tests, one before and one after the repetitive cycles, were performed to assess the stiffness of the clips. To this end, a custom-made stainless steel 0.40 x 0.40 mm wire was inserted into the bracket slot and adapted to the universal testing machine (EMIC DL2000), after which measurements were recorded. On the loading portion of the loading-unloading curve of clips, the slope fitted a first-degree equation curve to determine the stiffness/deflection rate of the clip.

RESULTS

The results of plastic deformation showed no significant difference among bracket types before and after the 500 cycles of opening and closure (p = 0.811). There were significant differences on stiffness among the three types of brackets (p = 0.005). The WOW bracket had higher mean values, whereas Quicklear bracket had lower values, regardless of the opening/closure cycle.

CONCLUSION

Repetitive controlled opening and closure movements of the clip did not alter stiffness or cause plastic deformation.

Differences of treatment outcomes between self-ligating brackets with microimplant and headgear anchorages in adults with bimaxillary protrusion

INTRODUCTION

Our aim was to determine differences between the outcomes of treatment using microimplant anchorage compared with headgear anchorage in adult patients with bimaxillary protrusion treated with self-ligating brackets.

METHODS

Thirty-one adult orthodontic patients (13 men, 18 women; age, 25.87 ± 3.37 years) who were diagnosed with bimaxillary protrusion were selected. All patients were treated with self-ligating brackets and maximum anchorage after extraction of 4 first premolars. Group 1 received microimplant anchorage, and group 2 received headgear. Lateral cephalometric radiographs were obtained before and after treatment. Differences in the skeletal and dental parameters between and within groups were analyzed.

RESULTS

No significant difference was observed in the mean treatment times between the groups (21.93 ± 3.10 vs 23.88 ± 2.68 months). There was no significant difference in skeletal measurements before or after treatment in patients who received microimplant anchorage. Patients who received headgear anchorage had an increase of the mandibular plane angle. The microimplant anchorage group had greater anterior tooth retraction and less maxillary molar mesialization than did the headgear group.

CONCLUSIONS

In both the anteroposterior and vertical directions, microimplant anchorage achieved better control than did the traditional headgear appliance during the treatment of bimaxillary protrusion.

A multi-center randomized controlled trial to compare a self-ligating bracket with a conventional bracket in a UK population: Part 1: Treatment efficiency

OBJECTIVE

To use a two-arm parallel trial to compare treatment efficiency between a self-ligating and a conventional preadjusted edgewise appliance system.

MATERIALS AND METHODS

A prospective multi-center randomized controlled clinical trial was conducted in three hospital orthodontic departments. Subjects were randomly allocated to receive treatment with either a self-ligating (3M SmartClip) or conventional (3M Victory) preadjusted edgewise appliance bracket system using a computer-generated random sequence concealed in opaque envelopes, with stratification for operator and center. Two operators followed a standardized protocol regarding bracket bonding procedure and archwire sequence. Efficiency of each ligation system was assessed by comparing the duration of treatment (months), total number of appointments (scheduled and emergency visits), and number of bracket bond failures.

RESULTS

One hundred thirty-eight subjects (mean age 14 years 11 months) were enrolled in the study, of which 135 subjects (97.8%) completed treatment. The mean treatment time and number of visits were 25.12 months and 19.97 visits in the SmartClip group and 25.80 months and 20.37 visits in the Victory group. The overall bond failure rate was 6.6% for the SmartClip and 7.2% for Victory, with a similar debond distribution between the two appliances. No significant differences were found between the bracket systems in any of the outcome measures. No serious harm was observed from either bracket system.

CONCLUSIONS

There was no clinically significant difference in treatment efficiency between treatment with a self-ligating bracket system and a conventional ligation system.

A multicenter randomized controlled trial to compare a self-ligating bracket with a conventional bracket in a UK population: Part 2: Pain perception

OBJECTIVE

To compare pain experience between self-ligating and conventional preadjusted edgewise appliance systems with a two-arm parallel trial.

MATERIALS AND METHODS

A prospective multicenter randomized controlled clinical trial was conducted in three hospital orthodontic departments. Subjects were randomly allocated to receive treatment with either a self-ligating (3M SmartClip™) or conventional (3M Victory™) bracket system with stratification for operator and center. Standardized protocol was followed for bracket bonding procedure and archwire sequence. Subject pain was recorded using a Verbal Rating Scale to assess discomfort felt on the teeth and soft tissues at the time of the appointment and 1, 3, and 5 days after each archwire change up to the working archwire. Multilevel modeling was used to analyze the data by blinded assessors.

RESULTS

One hundred thirty-eight subjects (mean age 14 years 11 months) were enrolled in the study, of which 135 subjects (97.8%) completed the study and 113 (82%) returned the required data regarding pain/discomfort. Perceived pain was statistically higher with the SmartClip™ system compared to the Victory™ system, but this difference was not deemed to be clinically significant. Discomfort was greatest after placement of the initial 0.014-inch nickel-titanium archwire, compared with subsequent wires, and was greatest on day 1, less on day 3, and much less on day 5 after each archwire change. Age and gender did not affect the level of discomfort experienced by subjects undergoing fixed appliance treatment.

CONCLUSION

No clinically significant difference in pain experience was found between patients treated with a self-ligating bracket system compared to those treated with a conventional ligation system.

Deflection Evaluation of Thermoactivated Nickel-Titanium Archwires after Heat Treatment on their Distal Ends

OBJECTIVE

This study evaluated in vitro the mechanical changes of 0.018" (0.45 mm) and 0.016 × 0.022" (0.40 × 0.55 mm) thermoactivated nickel-titanium archwires subjected to heat treatment on their distal ends.

MATERIALS AND METHODS

Ten archwires in diameters 0.018" and 0.016 × 0.022" by different manufacturers Ormco, Morelli, Orthometric and Unitek were tested. Each tested archwire had an experimental side, submitted to heat treatment, and an annealing-free control. Tests for load/deflection were performed using a universal testing machine, with temperature control in the austenitic transformation phase through tempe rature-controlled chamber. The variables showed normal distribution (Kolmogorov-Smirnov), the t-student test was applied in order to observe the difference between the experi mental and control groups. Statistical significance was set at p < 0.05.

RESULTS

There were no statistically significant differences between the groups.

CONCLUSION

Heat treatment carried out in the region corresponding to the first molar distal region on thermoactivated nickel-titanium archwires did not influence the load/deflection values in adjacent portion.

Stability of treatment with self-ligating brackets and conventional brackets in adolescents: a long-term follow-up retrospective study

OBJECTIVES

The aim of this study was to assess the long-term stability of treatment with self-ligating brackets compared with conventional brackets.

MATERIALS AND METHODS

The long-term follow-up retrospective study sample consisted of two groups of patients: group SL (including passive and interactive self ligating braces) comprised 30 subjects treated with self-ligating brackets at a mean pretreatment (T0) age of 13.56 years, with a mean follow up period for 7.24 years; group CL comprised 30 subjects treated with conventional brackets at a mean pretreatment age of 13.48 years, with a mean follow up period for 7.68 years. Relapse were evaluated by dental casts examination using the Peer Assessment Rating (PAR) index and the Little irregularity index. The two groups were evaluated for differences in the changing of PAR and Little irregularity index using paired-t tests. Inter-observer and intra-observer reliability was assessed by means of the Pearson's correlation coefficients method.

RESULTS

There were no significant differences changed in PAR and the Little irregularity index between groups for the long-term follow-up period.

CONCLUSIONS

The study revealed that brackets type did not affect the long-term stability. Considering self-ligating brackets were expensive, given comprehensive consideration for the patients to choose suitable orthodontic bracket type was of critical importance.

Randomized controlled clinical trial of oral health-related quality of life in patients wearing conventional and self-ligating brackets

OBJECTIVE

The aim of this randomized controlled clinical trial was to compare oral health-related quality of life (OHRQoL) of patients treated with conventional, active self-ligating (ASL), and passive self-ligating (PSL) brackets in different therapeutic phases.

METHODS

Sixty patients (mean age 18.3 years; 29 males and 31 females) requiring orthodontic treatment were randomly and equally assigned to receive conventional (Victory Series), ASL (In-Ovation R), or PSL (Damon 3MX) brackets. OHRQoL was measured with a self-administered modified 16-item Malaysian version of the Oral Health Impact Profile for immediate (soon after the visit) and late (just before the subsequent visit) assessments of the bonding and activation phases. Data were analyzed with the Kruskal-Wallis and chi-square tests.

RESULTS

The PSL and ASL groups showed more immediate and late impacts in the bonding phase, respectively; the conventional group was affected in both the assessments. The first activation phase had similar impacts in the groups. After the second activation, the conventional group showed more immediate impacts, whereas the PSL and ASL groups had more late impacts. The commonly affected domains were "physical disability," "functional limitation," "physical pain," and "psychological discomfort." No significant differences in the prevalence and severity of immediate and late impacts on OHRQoL of the patients were noted in any therapeutic phase.

CONCLUSIONS

No bracket system seems to ensure superior OHRQoL. This information could be useful for explaining the therapeutic phases, especially the initial one, and selecting the optimal bracket system based on the patient's preference.

Dental plaque associated with self-ligating brackets during the initial phase of orthodontic treatment: A 3-month preliminary study

BACKGROUND

To compare changes in the amount and distribution of dental plaque associated with placement of elastomeric modules over a self-ligating bracket during orthodontic treatment and to relate these changes to the periodontal inflammation.

MATERIALS AND METHODS

A cross-arch randomization trial was carried out at Bristol Dental School, United Kingdom. Clinical measurements of periodontal inflammation and plaque accumulation and microbiological test were done on 24 patients aged 11-14 years [Mean (SD) age = 12.6 (1.01) years] wearing fixed appliances (Damon 2 brackets, Ormco, Orange, CA, USA) at the start and 3 months into fixed orthodontic treatment.

RESULTS

In the first 3 months of treatment there was no statistically significant difference in bleeding on probing between incisors with and without elastomeric modules (P = 0.125 and 0.508, respectively). The difference in plaque accumulation was not statistically significant (P = 0.78). The difference in probing depths between the incisors was not statistically significant (P = 0.84). The microbiological analysis showed no difference.

CONCLUSIONS

Based on this preliminary 3 months study, elastomeric modules were not significantly associated with any increased risk during treatment when compared to self-ligating brackets. The longer term studies are needed to further confirm the findings of the present study.

Comparative assessment of alignment efficiency and space closure of active and passive self-ligating vs conventional appliances in adolescents: a single-center randomized controlled trial

INTRODUCTION

The aim of this study was to compare the time to initial alignment and extraction space closure using conventional brackets and active and passive self-ligating brackets.

METHODS

One hundred adolescent patients 11 to 18 years of age undergoing maxillary and mandibular fixed appliance therapy after the extraction of 4 premolars were randomized with stratification of 2 age ranges (11-14 and 15-18 years) and 3 maxillomandibular plane angles (high, medium, and low) with an allocation ratio of 1:2:2. Restrictions were applied using a block size of 10. Allocation was to 1 of 3 treatment groups: conventional brackets, active self-ligating, or passive self-ligating brackets. All subjects were treated with the same archwire sequence and space-closing mechanics in a district general hospital setting. The trial was a 3-arm parallel design. Labial-segment alignment and space closure were measured on study models taken every 12 weeks throughout treatment. All measurements were made by 1 operator who was blinded to bracket type. The patients and other operators were not blinded to bracket type during treatment.

RESULTS

Ninety-eight patients were followed to completion of treatment (conventional, n = 20; active self-ligating brackets, n = 37; passive self-ligating brackets, n = 41). The data were analyzed using linear mixed models and demonstrated a significant effect of bracket type on the time to initial alignment (P = 0.001), which was shorter with the conventional brackets than either of the self-ligating brackets. Sidak's adjustment showed no significant difference in effect size (the difference in average response in millimeters) between the active and passive self-ligating brackets (the results are presented as effect size, 95% confidence intervals, probabilities, and intraclass correlation coefficients) (-0.42 [-1.32, 0.48], 0.600, 0.15), but the conventional bracket was significantly different from both of these (-1.98 [-3.19, -0.76], 0.001, 0.15; and -1.56 [-2.79, -0.32], 0.001, 0.15). There was no statistically significant difference between any of the 3 bracket types with respect to space closure. Space-closure times were shorter in the mandible, except for the Damon 3MX bracket (Ormco, Orange, Calif), where active and total space-closure times were shorter in the maxilla. No adverse events were recorded in the trial.

CONCLUSIONS

Time to initial alignment was significantly shorter for the conventional bracket than for either the active or passive self-ligating brackets. There was no statistically significant difference in passive, active, or total space-closure times among the 3 brackets under investigation.

Geometric morphometric evaluations of a randomized prospective split-mouth study on modes of ligation and reverse-curve mechanics

OBJECTIVES

To evaluate tooth position after six and 9 months of orthodontics with conventional brackets on one side of the dentition and ligature-less brackets on the other.

SETTING AND SAMPLE POPULATION

Orthodontic Division, Vienna Medical University. Twenty patients aged 22.5 ± 5.7 years, symmetrical malocclusion and arch form, no premolar extraction.

MATERIAL AND METHODS

Prospective split-mouth study, 0.022-inch SmartClip self-ligating brackets assigned randomly to the left or right dentition, conventional 0.018-inch brackets on the other side. 52 dental landmarks, digitized on plaster casts, represented dental arches at baseline (t0), 6 months and 9 months (t1, t2). During t0-t1, we used 0.016 and 0.014 x 0.025 inch superelastic wires, during t1-t2 connected reverse-curve hemiarch wires: 0.017 x 0.025 inch ß-titanium on the ligature-less side, and 0.016 x 0.022 inch Elgiloy multiloop wires on conventional brackets. Morphometric analyses were used to assess differences in dental arch shapes.

RESULTS

Neither initial alignment nor the reverse-curve phase showed statistically significant differences between ligature-less and conventional brackets in moving teeth.

CONCLUSION

Morphometric shape analyses corroborated current evidence that self-ligating brackets were no more effective than conventional brackets with steel ligatures after 6-month initial alignment. From months 6-9 treatment with ß-titanium reverse-curve wires on 0.022-inch ligature-less brackets resulted in similar tooth positions as accomplished by Elgiloy multiloop wires on 0.018-inch steel-ligature-tied brackets.

Does the bracket-ligature combination affect the amount of orthodontic space closure over three months? A randomized controlled trial

Objective: To investigate the effect of bracket–ligature combination on the amount of orthodontic space closure over three months.

Design: Randomized clinical trial with three parallel groups.

Setting: A hospital orthodontic department (Chesterfield Royal Hospital, UK).

Participants: Forty-five patients requiring upper first premolar extractions.

Methods: Informed consent was obtained and participants were randomly allocated into one of three groups: (1) conventional pre-adjusted edgewise brackets and elastomeric ligatures; (2) conventional pre-adjusted edgewise brackets and Super Slick® low friction elastomeric ligatures; (3) Damon 3MX® passive self-ligating brackets. Space closure was undertaken on 0·019×0·025-inch stainless steel archwires with nickel–titanium coil springs. Participants were recalled at four weekly intervals. Upper alginate impressions were taken at each visit (maximum three). The primary outcome measure was the mean amount of space closure in a 3-month period.

Results: A one-way ANOVA was undertaken [dependent variable: mean space closure (mm); independent variable: group allocation]. The amount of space closure was very similar between the three groups (1 mm per 28 days); however, there was a wide variation in the rate of space closure between individuals. The differences in the amount of space closure over three months between the three groups was very small and non-significant (P = 0·718).

Conclusion: The hypothesis that reducing friction by modifying the bracket/ligature interface increases the rate of space closure was not supported. The major determinant of orthodontic tooth movement is probably the individual patient response.

Are self-ligating brackets related to less formation of Streptococcus mutans colonies? A systematic review

OBJECTIVE

To verify, by means of a systematic review, whether the design of brackets (conventional or self-ligating) influences adhesion and formation of Streptococcus mutans colonies.

METHODS

SEARCH STRATEGY

four databases (Cochrane Central Register of Controlled Trials, Ovid ALL EMB Reviews, PubMed and BIREME) were selected to search for relevant articles covering the period from January 1965 to December 2012.

SELECTION CRITERIA

in first consensus by reading the title and abstract. The full text was obtained from publications that met the inclusion criteria.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data using the following keywords: conventional, self-ligating, biofilm, Streptococcus mutans, and systematic review; and independently evaluated the quality of the studies. In case of divergence, the technique of consensus was adopted.

RESULTS

The search strategy resulted in 1,401 articles. The classification of scientific relevance revealed the high quality of the 6 eligible articles of which outcomes were not unanimous in reporting not only the influence of the design of the brackets (conventional or self-ligating) over adhesion and formation of colonies of Streptococcus mutans, but also that other factors such as the quality of the bracket type, the level of individual oral hygiene, bonding and age may have greater influence. Statistical analysis was not feasible because of the heterogeneous methodological design.

CONCLUSIONS

Within the limitations of this study, it was concluded that there is no evidence for a possible influence of the design of the brackets (conventional or self-ligating) over colony formation and adhesion of Streptococcus mutans.

The timing of significant arch dimensional changes with fixed orthodontic appliances: data from a multicenter randomised controlled trial

OBJECTIVES

To identify the timing of significant arch dimensional increases during orthodontic alignment involving round and rectangular nickel-titanium (NiTi) wires and rectangular stainless steel (SS). A secondary aim was to compare the timing of changes occurring with conventional and self-ligating fixed appliance systems.

METHODS

In this non-primary publication, additional data from a multicenter randomised trial initially involving 96 patients, aged 16 years and above, were analysed. The main pre-specified outcome measures were the magnitude and timing of maxillary intercanine, interpremolar, and intermolar dimensions. Each participant underwent alignment with a standard Damon (Ormco, Orange, CA) wire sequence for a minimum of 34 weeks. Blinding of clinicians and patients was not possible; however, outcome assessors and data analysts were kept blind to the appliance type during data analysis.

RESULTS

Complete data were obtained from 71 subjects. Significant arch dimensional changes were observed relatively early in treatment. In particular, changes in maxillary inter-first and second premolar dimensions occurred after alignment with an 0.014in. NiTi wire (P<0.05). No statistical differences in transverse dimensions were found between rectangular NiTi and working SS wires for each transverse dimension (P>0.05). Bracket type had no significant effect on the timing of the transverse dimensional changes.

CONCLUSIONS

Arch dimensional changes were found to occur relatively early in treatment, irrespective of the appliance type. Nickel-titanium wires may have a more profound effect on transverse dimensions than previously believed.

CLINICAL SIGNIFICANCE

On the basis of this research orthodontic expansion may occur relatively early in treatment. Nickel-titanium wires may have a more profound effect on transverse dimensions than previously believed.

Photobiomodulation accelerates orthodontic alignment in the early phase of treatment

Background

Numerous strategies have been proposed to decrease the treatment time a patient requires in orthodontic treatment. Recently, a number of device-accelerated therapies have emerged in orthodontics. Photobiomodulation is an emerging area of science that has clinical applications in a number of human biological processes. The aim of this study was to determine if photobiomodulation reduces the treatment time in the alignment phase of orthodontic treatment.

Methods

This multicenter clinical trial was performed on 90 subjects (73 test subjects and 17 controls), and Little's Index of Irregularity (LII) was used as a measure of the rate of change of tooth movement. Subjects requiring orthodontic treatment were recruited into the study, and the LII was measured at regular time intervals. Test subjects used a device which produced near-infrared light with a continuous 850-nm wavelength. The surface of the cheek was irradiated with a power density of 60 mW/cm² for 20 or 30 min/day or 60 min/week to achieve total energy densities of 72, 108, or 216 J/cm², respectively. All subjects were fitted with traditional orthodontic brackets and wires. The wire sequences for each site were standardized to an initial round alignment wire (014 NiTi or 016 NiTi) and then advanced through a progression of stiffer arch wires unit alignment occurred (LII < 1 mm).

Results

The mean LII scores at the start of the clinical trial for the test and control groups were 6.35 and 5.04 mm, respectively. Multi-level mixed effect regression analysis was performed on the data, and the mean rate of change in LII was 0.49 and 1.12 mm/week for the control and test groups, respectively.

Conclusions

Photobiomodulation produced clinically significant changes in the rates of tooth movement as compared to the control group during the alignment phase of orthodontic treatment.

Comparison of static friction with self-ligating, modified slot design and conventional brackets

OBJECTIVE

To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters.

MATERIAL AND METHODS

The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA), with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA) and conventional (Kirium, Abzil, São José do Rio Preto, Brazil). The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA). The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil) with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test.

RESULTS

There was a significant difference (p<0.05) in static friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (p<0.05). The angulation influenced friction (p<0.05) when the brackets were associated with a 0.018" wire.

CONCLUSION

Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested.

Effect of text message follow-up on patient's self-reported level of pain and anxiety

OBJECTIVES

To determine whether a text message reduces the severity of patient self-reported levels of pain and anxiety following initial placement of orthodontic appliances.

MATERIALS AND METHODS

Thirty-nine orthodontic patients were randomly assigned to one of two groups and matched for age, gender, and bracket type (self-ligating vs conventional). The subjects completed baseline questionnaires to ascertain their levels of pain and anxiety before initiating orthodontic treatment. Following the initial appointment, subjects completed the pain questionnaire and anxiety inventory at the same time daily for 1 week. One group received a structured text message showing concern and reassurance, while the second group served as a control and received no postprocedural communication.

RESULTS

There was a statistically significant difference in pain in relation to time between the text message group and the control group as it was demonstrated that demonstrated that compared with the text message group, mean pain intensity increased and selfreported discomfort was longer in the control group. Anxiety was determined to be at its peak the day following initial orthodontic appliance placement and gradually tapered off from that time point. No intergroup difference was noted when analyzing anxiety.

CONCLUSIONS

This study demonstrated that a text message sent from an orthodontic office following initial appliance placement resulted in a lower level of patient's self-reported pain. Additionally, patient anxiety is at its peak the day following the initial appointment and decreases from that point forward.

Systematic review on self-ligating vs. conventional brackets: initial pain, number of visits, treatment time

OBJECTIVE

Meta-analysis of differences between conventional and self-ligating brackets concerning pain during tooth movement, number of patient visits, total treatment duration, and ligation times.

MATERIALS AND METHODS

Online search in Medline, Embase, and Central focused on randomized clinical trials and controlled clinical studies published between 1996 and 2012.

RESULTS

Four studies on pain met our inclusion criteria, two on the number of appointments, two on overall treatment time but none on ligation times. Pain levels did not differ significantly between patients treated with conventional or self-ligating brackets after 4 h, 24 h, 3 and 7 days. The number of appointments and total treatment times revealed no significant differences between self-ligating and conventional brackets.

CONCLUSION

The lack of significant overall effects apparent in this meta-analysis contradicts evidence-based statements on the advantages of self-ligating brackets over conventional ones regarding discomfort during initial orthodontic therapy, number of appointments, and total treatment time. Due to the limited number of studies included, further randomized controlled clinical trials are required to deliver more data and to substantiate evidence-based conclusions on differences between the two bracket types considering orthodontic pain, number of visits, treatment, and ligation times.

Comparison of static friction with self-ligating, modified slot design and conventional brackets

OBJECTIVE

To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters.

MATERIAL AND METHODS

The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA), with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA) and conventional (Kirium, Abzil, São José do Rio Preto, Brazil). The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA). The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil) with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test.

RESULTS

There was a significant difference (p<0.05) in static friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (p<0.05). The angulation influenced friction (p<0.05) when the brackets were associated with a 0.018" wire.

CONCLUSION

Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested.

Self-ligating fully customized lingual appliance and chair-time reduction: a typodont study followed by a randomized clinical trial

In this study, we tested the hypothesis that self-ligation can reduce the chair time necessary for inserting and removing the archwire in a fully customized, multi-bracket, orthodontic, lingual appliance. A permuted-block, randomized trial design was employed to treat seven patients, each with Incognito(®) lingual appliances and Harmony(®) self-ligating lingual appliances. Three operators (a third year resident in orthodontics, an orthodontic specialist, and an experienced lingual orthodontist) were instructed, and they were allowed to familiarize themselves with two typodonts. Next, the operators were asked to insert and remove a.014 NiTi customized archwire for each patient, and they were timed. The time required for removing and inserting archwires decreased proportionally with operator experience: it was shorter with self-ligating appliances (114.82±18.06 seconds versus 595.83±289.09 seconds, P < 0.001) and when testing the typodonts' performances (480.61±285.74 seconds versus 518.65±296.97 seconds, P < 0.001). However, differences between operators were smaller when using typodonts (31.77±21.19 seconds versus 43.87±27.06 seconds, P < 0.001) and with self-ligation (15.17±9.29 seconds versus 45.37±25.44 seconds, P < 0.001). In vivo performance improved after typodont training, allowing for difference reductions between operators. Lingual self-ligation appears to require less hands-on ability and training of the orthodontist, for reduction of chair time.

Self-ligating vs conventional brackets as perceived by orthodontists

OBJECTIVE

To determine if there are significant clinical differences between self-ligating brackets (SLB) and conventional brackets (CB) during orthodontic treatment, as perceived by orthodontists.

MATERIALS AND METHODS

A survey was developed and distributed to evaluate how SLB compare to CB in terms of orthodontists' perceptions (n  =  430).

RESULTS

SLB were preferred during the initial stage of treatment based on the shorter adjustment appointments and faster initial treatment progress they provided (P < .0001). On the other hand, practitioners preferred CB during the finishing and detailing stages of treatment (P < .0001). CB were also preferred over SLB because they were cheaper and resulted in fewer emergency appointments.

CONCLUSIONS

The orthodontists' preference was significantly influenced by (1) the proportion of patients treated with SLB (P < .0001), (2) the number of cases it took them to become accustomed to SLB (P < .0001), and (3) the average appointment intervals associated with SLB (P < .0001).

Orthodontic treatment efficiency with self-ligating and conventional edgewise twin brackets: a prospective randomized clinical trial

OBJECTIVE

To conduct a prospective and randomized study of the efficiency of orthodontic treatment with self-ligating edgewise brackets (SL; Time2 brand, American Orthodontics) and conventional edgewise twin brackets (CE; Gemini brand, 3M).

MATERIALS AND METHODS

One hundred consecutive patients were randomized to treatment with either SL or CE brackets. The participants were treated by one of three specialists in orthodontics and with continuous instructions alternately by five orthodontic assistants according to our normal treatment routine (ie, modified 0.022" MBT preadjusted edgewise technique). The treatments were evaluated in terms of overall treatment time, number of visits, and treatment outcome using the Index of Complexity, Outcome and Need (ICON). The number of emergency appointments, number of archwires, overjet, relative space, and extractions at treatment start were noted.

RESULTS

After dropouts, the analyzed material consisted of 44 patients treated with SL (mean age 15.3 years, mean ICON 60.7, 70.4% female) and 46 patients treated with CE (mean age 15.0 years, mean ICON 56.5, 71.7% female). There were no statistically significant differences between the SL and CE groups in terms of mean treatment time in months (20.4 vs 18.2), mean number of visits (15.5 vs 14.1), mean ICON scores after treatment (13.2 vs 11.9), or mean ICON improvement grade (7.9 vs 9.1).

CONCLUSION

Orthodontic treatment with SL brackets does not reduce treatment time or number of appointments and does not affect posttreatment ICON scores or ICON improvement grade compared with CE brackets.

A prospective randomized split-mouth study on pain experience during chairside archwire manipulation in self-ligating and conventional brackets

OBJECTIVE

To investigate patient discomfort during archwire engagement and disengagement in patients treated with self-ligating and conventional brackets using a split-mouth design.

MATERIALS AND METHODS

Eighteen consecutive patients (15 female, 3 male; age: 22.2 ± 6.4 years) who requested treatment with fixed orthodontic appliances were randomly assigned for bonding with SmartClip self-ligating brackets on one side of the dentition and conventional standard edgewise brackets on the other. During the course of treatment, patients rated the discomfort experienced during every archwire engagement and disengagement using a numeric rating scale. Results were evaluated for round and rectangular nickel titanium and rectangular stainless steel, titanium molybdenum, and Elgiloy archwires. Patients also rated their overall experience retrospectively for both bracket systems.

RESULTS

Regardless of archwire type, disengagement was rated as being significantly more painful on the SmartClip side (P  =  .027). For rigid, rectangular archwires, engagement and disengagement were rated as being significantly more painful on the SmartClip side (P  =  .031; P  =  .004). Retrospective ratings favored conventional brackets beyond ratings recorded during treatment.

CONCLUSION

Engagement and disengagement of rigid rectangular archwires caused more pain with SmartClip self-ligating brackets than with conventional ones. Careful archwire manipulation and patience during full alignment are essential for limiting chairside pain. Low pain levels will help ensure treatment satisfaction and compliance.

Gingival recession and adult orthodontics: a clinical evidence-based treatment proposal

The presence of a gingival recession prior to orthodontic treatment is a real problem. Patients are concerned about losing their teeth but may also complain of their unpleasant appearance or root sensitivity in the exposed area. The orthodontist is not sure whether orthodontic treatment can be performed or whether the tooth movement will not aggravate the recession and whether periodontal surgery needs to be done before or after orthodontic treatment. The aim of this paper is to present recent data from the literature and several clinical situations in adults in order to submit a treatment sequence and clarify the role of different periodontal plastic surgery root coverage procedures.

In vitro oxidative stress induced by conventional and self-ligating brackets

OBJECTIVE

To determine the in vitro oxidative stress induced by conventional and self-ligating brackets made of different materials.

MATERIALS AND METHODS

The concentration of oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA of murine fibroblast cells L929 after in vitro exposure to three types of conventional and four types of self-ligating brackets was assessed. To determine viability and changes in the number of cells before and after exposure, trypan blue dye was used. Analysis of variance (ANOVA) was used for statistical analysis.

RESULTS

No significant difference in cell viability was noted between metal, ceramic, and polymeric conventional brackets, and self-ligating brackets made of combinations of those materials, but viability was significantly higher compared with positive controls (P < .05). The conventional sapphire ceramic bracket (Inspire Ice) showed high viability, the largest increase in the number of cells, and the lowest oxidative stress. A higher concentration of markers of oxidative stress was observed in full metal conventional and self-ligating brackets (MiniSprint and Speed) and in conventional polyurethane brackets (Quantum) compared with negative controls (P < .05).

CONCLUSION

All types of orthodontic brackets, regardless of the constituent materials, are a source of oxidative stress in vitro, but the highest stress was induced in the full metal and polyurethane brackets. Conventional ceramic brackets show the highest degree of biocompatibility compared with polymeric and metal brackets and self-ligating brackets made from combinations of these materials.

Reconditioning of self-ligating brackets

OBJECTIVE

To test the null hypothesis that there is no significant difference in the shear bond strength (SBS) and Adhesive Remnant Index (ARI) scores of new vs reconditioned self-ligating brackets.

MATERIALS AND METHODS

One hundred and twenty permanent extracted bovine teeth were embedded in resin blocks. Three different new and reconditioned self-ligating orthodontic brackets (Smart Clip [3M Unitek]; Quick [Forestadent]; and Damon3MX [Ormco]) were tested. Scanning electron microphotographs of the different new (groups 1, 3, and 5) and reconditioned (groups 2, 4, and 6) bracket bases were taken before starting the experiments. Brackets were then bonded to the teeth using an orthodontic adhesive and were then tested in shear mode using an Instron Universal Testing Machine. ARI scores were then recorded. Statistical analysis was performed to determine significant differences in SBS and ARI Scores.

RESULTS

Smart Clip and Damon3MX reconditioned brackets showed significantly lower SBS than did new ones. On the contrary, Quick reconditioned brackets showed significantly higher SBS than did new ones. No significant differences in ARI scores were found after the reconditioning process for the three different brackets tested.

CONCLUSION

The in-office reconditioning procedure alters the SBS of self-ligating brackets, although SBS values still remain clinically acceptable.

An in vitro comparison of the frictional forces between archwires and self-ligating brackets of passive and active types

The aim of this study was to compare the static and kinetic frictional forces generated by various contemporary designs of self-ligating brackets (SLBs) and different wire alloys. In total, six different brackets (four passive type SLB, one active SLB, and one conventional bracket) were investigated using stainless steel, nickel-titanium, and titanium-molybdenum alloy archwires of several sizes. The friction forces were measured by sliding on a bracket-wire combination system in an EZ instron testing machine. A scanning electron microscope (SEM) was used to examine the wear effects of the wall surfaces of bracket slots. Energy-dispersive spectroscopy (EDS) was used to identify the elemental compositions of the bracket surfaces. The data were collected and statistically analysed using analysis of variance. The results of static and kinetic frictional forces were lower in passive type SLBs (P < 0.05), except in the Smart Clip bracket. The wire materials or wire dimensions in the present study showed similar friction forces with no statistical differences (P > 0.05). The wearing effects were not obviously found in bracket slots under SEM observation. Only conventional brackets and mini-Clippy SLB revealed nickel ions via EDS analysis. This study shows that passive SLBs are associated with lower static or kinetic friction forces than those of active SLBs or conventional brackets. Wear on the bracket slots was not observed in the present study.

Duration of treatment and occlusal outcome using Damon3 self-ligated and conventional orthodontic bracket systems in extraction patients: a prospective randomized clinical trial

INTRODUCTION

This was a prospective randomized clinical trial comparing the effect of bracket type on the duration of orthodontic treatment and the occlusal outcome as measured by the peer assessment rating (PAR).

METHODS

A multi-center randomized clinical trial was carried out in 2 orthodontic clinics. Sixty-two subjects (32 male, 30 female; mean age, 16.27 years) with a mean pretreatment PAR score of 39.40, mandibular irregularity from 5 to 12 mm, and prescribed extractions including mandibular first premolars were randomly allocated to treatment with either the Damon3 self-ligated or the Synthesis conventional ligated preadjusted bracket systems (both, Ormco, Glendora, Calif). An identical archwire sequence was used in both groups excluding the finishing archwires: 0.014-in, 0.014 × 0.025-in, and 0.018 × 0.025-in copper-nickel-titanium aligning archwires, followed by 0.019 × 0.025-in stainless steel working archwires. Data collected at the start of treatment and after appliance removal included dental study casts, total duration of treatment, number of visits, number of emergency visits and breakages during treatment, and number of failed appointments.

RESULTS

Sixty-two patients were recruited at the start of treatment, and the records of 48 patients were analyzed after appliance removal. Accounting for pretreatment and in-treatment covariates, bracket type had no effect on overall treatment duration, number of visits, or overall percentage of reduction in PAR scores. Time spent in space closure had an effect on treatment duration, and the pretreatment PAR score influenced only the reduction in PAR as a result of treatment.

CONCLUSIONS

Use of the Damon3 bracket does not reduce overall treatment time or total number of visits, or result in a better occlusal outcome when compared with conventional ligated brackets in the treatment of extraction patients with crowding.