The effect of ligation methods on biofilm formation in patients undergoing multi-bracketed fixed orthodontic therapy - A systematic review

BACKGROUND

Many modifications to fixed orthodontic appliances have been introduced to manage biofilm formation. The aim of this review was to investigate elastomeric ligation in comparison with stainless steel ligation and self-ligation with regard to microbiological and clinical indicators of biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances.

METHODS

The MEDLINE and the EMBASE databases were searched up to February 2021 and supplemented by additional manual searches of bibliographies. Parallel-group and split-mouth randomized controlled trials (RCTs) comparing different ligation methods were identified. The Cochrane Risk of Bias-2 tool was applied to assess the quality of evidence.

RESULTS

A total of 11 RCTs were included in this review. Nine RCTs compared self-ligation and elastomeric ligation; two compared elastomeric ligation and stainless steel ligation. The included studies had either some concerns or were at a high risk of bias. Qualitative assessment of the studies identified that there were no significant differences in biofilm formation between elastomeric ligation and self-ligation, but that stainless steel ligation was less susceptible to biofilm formation than elastomeric ligation.

CONCLUSIONS

There were no significant differences between self-ligation and elastomeric ligation for biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances. Stainless steel ligation may accumulate less biofilm than elastomeric ligation; however, the clinical significance of the difference could not be evaluated. Further high-quality studies are required in order to determine which ligation method is better for managing biofilm formation in patients wearing multi-bracketed fixed orthodontic appliances.

Comparison of self-ligating Damon3 and conventional MBT brackets regarding alignment efficiency and pain experience: A randomized clinical trial

Background. Self-ligating brackets might be more efficient than conventional appliance systems during the initial alignment stage of orthodontic treatment due to reduced frictional resistance. This study aimed to compare the alignment efficiency and pain experience of Damon3 self-ligating and MBT pre-adjusted brackets in the initial alignment stage.

Methods. In this randomized clinical trial, 30 patients aged 14‒20 years, who needed non-extraction treatment in both maxillary and mandibular arches, were randomly assigned to two groups; 15 patients were treated with MBT pre-adjusted brackets, and 15 patients received Damon3 self-ligating brackets, both with 0.022-in slots. Alginate impressions were taken at the start of treatment (T0) and four monthly visits (T1, T2, T3, and T4). Little’s irregularity index (LII) was used to assess the tooth displacements. The patients rated their pain experience immediately after the insertion of the archwire, 4 hours, 24 hours, 3 days, 7 days, and at each monthly visit using a visual analog scale (VAS).

Results. The rate of upper dental alignment between T0 and T4 was significantly higher with the Damon3 compared to MBT brackets (P=0.015). Although significantly more changes in the lower LII scores were observed during the first three months with the Damon3 system, the rate of improvement in the irregularity of lower teeth over the 4-month period was not significantly different between the two groups (P=0.50). The patients’ pain experience was not significantly different between the bracket groups (P=0.29).

Conclusion. During the four-month alignment stage, significantly more improvement in the upper dental irregularity was observed with self-ligating compared to conventional brackets. The bracket type had no effect on pain experience during the alignment stage.

Periodontal parameters in adult patients with clear aligners orthodontics treatment versus three other types of brackets: A cross-sectional study

OBJECTIVE:

To assess the gingival parameters in the clear aligner treatment versus the three other types of brackets, i.e., conventional metal, conventional ceramic, and metal self-ligating.

MATERIALS AND METHODS:

Eighty patients coming for regular appointments undergoing orthodontic treatment were included. They were further divided into four groups with 20 patients in each: Group one underwent conventional brackets (CB) treatment; Group two had conventional ceramic brackets (CCB); Group three was treated with self-ligating (SL) brackets; Group four underwent with clear aligner (CA) treatment. Inclusion criteria were any patient with a minimum age of 18 years having Class II, Class III skeletal relationship, undergoing orthodontic treatment for at least 6 months with fixed orthodontic appliances (FOA) on both arches. While smokers, pregnant, diabetics, or those taking medication affecting gingival health or having cardiovascular diseases were excluded. Also excluded were patients who used antiseptic solutions or mouthwash during the past 6 months, underwent any periodontal treatments in the past 6 months, or who had fixed bridges and crowns or extensive restorations close to the gingival margins. Seven indices, namely plaque index, gingival index, gingival bleeding index, sulcus bleeding index, papillary bleeding index, basic periodontal examination index, and bleeding on probing index, were recorded for all groups.

RESULTS:

Mean age for Group 1 with CB was 26.65 ± 5.15 years, whereas it was 27.65 ± 8.15 years for Group 2 with CCB, and 26.85 ± 5.19 for Group 3 with SB. Group-4 with CA treatment had a mean age of 26.85 ± 4.83 years. Multivariate analysis and a Bonferroni correction was performed (P = 0.008). CA treatment has better periodontal parameter values compared with the CB and the CCB groups, and no significance difference with the SL brackets group.

CONCLUSION:

CA treatment has better periodontal indices levels compared to other types of orthodontic treatments such as CB and the CCB groups; no significant difference with the SL brackets group. Importance should be given to oral hygiene instructions before, during, and after the treatment.

Dental inclination with self-ligating and conventional fixed appliances, with and without rapid maxillary expansion

OBJECTIVE

To compare the labio- and buccolingual inclination of the anterior and posterior teeth in subjects treated with self-ligating and conventional fixed appliances with and without rapid maxillary expansion.

METHODS

Seventy-one subjects with Class I malocclusion were divided into three groups. Group 1 comprised 24 subjects (17 female; seven male, with a mean age of 13.94 ± 2.87 years), treated with Roth's pre-adjusted fixed appliances. Group 2 comprised 24 subjects (14 female; 10 male, with a mean age of 13.85 ± 1.83 years) treated with Rapid Maxillary Expansion followed by Roth's pre-adjusted fixed appliances. Group 3 comprised 23 patients (12 female; 11 male, with a mean age of 14.75 ± 1.34 years) treated with Damon self-ligating bracket system. Buccolingual inclination was measured on digital dental models using a 3D software. Intergroup changes comparison was performed with one-way ANOVA, followed by Tukey tests.

RESULTS

The left maxillary lateral incisor showed labial inclination in the conventional and RME groups, and palatal inclination in the Damon group. The Damon group showed greater buccal inclination in most posterior mandibular teeth during treatment than the conventional and RME groups. The right mandibular canine and lateral incisor showed greater labial inclination in the Damon group than in the RME group.

CONCLUSIONS

There was greater buccal inclination of the posterior mandibular teeth and labial inclination of the right mandibular canine and lateral incisor in the Damon group.

In vitro evaluation of the influence of velocity on sliding resistance of stainless steel arch wires in a self-ligating orthodontic bracket

INTRODUCTION

Of the variables used by in vitro studies of resistance to sliding (RS) in orthodontics, sliding velocity (SV) of the wire is often the one farthest from its clinical counterpart. We investigated whether velocity influences the RS at values approximating the orthodontic movement.

METHODS

A SS self-ligating bracket with a NiTi clip was fixed onto a custom-made model. Different shaped orthodontic SS wires of four sizes and two types (round, 0.020″ and 0.022″; rectangular, 0.016″×0.022″ and 0.017″×0.025″) were tested using an Instron^® testing machine. Wires were pulled at four velocities (1×10^-2  mm/s, 1×10^-3  mm/s, 1×10^-4  mm/s, 1×10^-5  mm/s). Shapiro-Wilk test was used to evaluate the normal distribution of the data; two-way ANOVA was performed to compare means in the RS with wire characteristics and SV. Significance level was set at P<.05.

RESULTS

RS was higher for rectangular wires, and for those with larger diameters. Lower SV was associated with lower RS, with wire type and size having an interaction effect. The RS relatively to SV can be represented as: RS ∝ α[ln(SV)]+β, where α and β are constants.

CONCLUSIONS

At very low SV and low normal forces, SV influences the RS of SS archwires in orthodontic brackets, and the proportionality is logarithmic. Although respecting these parameters in vitro is challenging, quantitative evaluations of RS should be carried out at clinically relevant velocities if aiming at translational application in the clinical scenario.

Comparative evaluation of efficacy of self-ligating interactive bracket with conventional preadjusted bracket: A clinical study

Aims and Objectives:

This clinical study was conducted to compare the interactive self-ligating twin brackets and the standard double width brackets for their efficiency in Rate of Retraction.

Materials and Methods:

A total of 20 patients with Angle's class I or class II or class III dento-alveolar malocclusions between the age group of 18-25 years were selected. 10 patients in each group both males and females were randomly selected for the study. Ten patients were bonded using conventional brackets (Group I) the other ten patients were bonded using Interactive self-ligating brackets (Group II). The Rate of retraction was quantified using the scanned models. Pretreatment and post treatment models were taken and scanned to measure the amount of Incisor movement and Anchor loss.

Results:

(1) Interactive Self-ligating brackets showed significant Rate of retraction when compared with conventional brackets on right and left quadrant. (Group I 0.545 ± .205: Group II 0.827 ± .208 P = .013*) (Group I 0.598 ± .160: Group II 0.804 ± .268 P = .071) (2) Interactive self-ligating brackets when compared with conventional brackets had significant amount of incisor movement on right and left quadrant. (Group I 3.51 ± .548: Group II 4.38 ± .1.06 P = .047*) and (Group I 3.66 ± .899: Group II 4.67 ± 1.02 P = .047*) (3) Conventional brackets showed significant Amount of Anchor loss when compared with that of Interactive self-ligating brackets on right and left quadrant. (Group I .948 ± .392: Group II 0.501 ± .229 P = .013*). In the left side (Group I 0.861 ± .464: Group II 0.498 ± .227 P = .060).

Conclusion:

The interactive self-ligating brackets show more efficiency in Rate of Retraction, Amount of Incisor movement and Amount of Anchor loss when compared with the conventional 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.

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.

Self-ligating versus Invisalign: analysis of dento-alveolar effects

AIM

The aim of this study was to evaluate the changes in the transverse dimension and the perimeter of the maxillary arch produced by low friction self-ligating brackets TIME 3 compared to the Invisalign technique.

MATERIALS AND METHODS

Both the self-ligating sample and the Invisalign group were composed of 20 subjects, evaluated at the beginning (T0) and at the completion of therapy (T1). All subjects presented a Class I malocclusion with mild crowding in a permanent dentition, without craniofacial anomalies, missing teeth or a history of orthodontic treatment. Dento-alveolar measurements were made on the maxillary dental casts at T0 and T1. Significant differences between the treated groups were assessed with Independent Samples t test (p<0.05).

RESULTS

Statistically significant differences between self-ligating sample and Invisalign group were recorded for CWC, FPWF, FPWL, SPWF, SPWL, and AP measurements. No significant changes were found for CWL, MWF, MWL, and AD values. There was not a statistically significant difference between the treatment durations of the groups: 1.8 years for both patients. These data suggest that Invisalign treatment cannot be somewhat faster than fixed appliances. Moreover the final occlusion might not be as ideal.

CONCLUSIONS

The low fiction self-ligating system produced statistically significant different outcomes in the transverse dento-alveolar width and the perimeter of the maxillary arch during treatment when compared to Invisalign tecnique.

Canine retraction rate with self-ligating brackets vs conventional edgewise brackets

OBJECTIVE

To compare the rates of retraction down an archwire of maxillary canine teeth when bracketed with a self-ligating bracket was used on one side and a conventional bracket on the other.

MATERIALS AND METHODS

In 43 patients requiring maxillary premolar extraction, a self-ligating bracket (Damon3, SmartClip) was used on the maxillary canine on one side and a conventional bracket (Victory Series) on the other. The teeth were retracted down a 0.018-inch stainless steel archwire, using a medium Sentalloy retraction spring (150 g). The rates of retraction were analyzed using a paired t-test.

RESULTS

The mean movement per 28 days for the conventional bracket was 1.17 mm. For the Damon bracket it was 0.9 mm and for the SmartClip bracket it was 1.10 mm. The differences between the conventional and self-ligating brackets were statistically significant: paired t-test, SmartClip, P < .0043; Damon3, P < .0001).

CONCLUSION

The retraction rate is faster with the conventional bracket, probably because of the narrower bracket width of the self-ligating brackets.

A systematic review

OBJECTIVE

To evaluate the clinical differences in relation to the use of self-ligating brackets in orthodontics.

MATERIALS AND METHODS

Electronic databases were searched; no restrictions relating to publication status or language of publication were applied. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) investigating the influence of bracket type on alignment efficiency, subjective pain experience, bond failure rate, arch dimensional changes, rate of orthodontic space closure, periodontal outcomes, and root resorption were selected. Both authors were involved in study selection, validity assessment, and data extraction. Disagreements were resolved by discussion.

RESULTS

Six RCTs and 11 CCTs were identified. Meta-analysis of the influence of bracket type on subjective pain experience failed to demonstrate a significant advantage for either type of appliance. Statistical analysis of other outcomes was unfeasible because of inadequate methodological design and heterogenous designs.

CONCLUSIONS

At this stage there is insufficient high-quality evidence to support the use of self-ligating fixed orthodontic appliances over conventional appliance systems or vice versa.