A comparative anchorage control study between conventional and self-ligating bracket systems using differential moments

Canine retraction and anchorage loss using self-ligating and conventional brackets with sliding mechanics: A split-mouth clinical study

OBJECTIVE

Appliance biocompatibility, orthodontic treatment efficiency and patient convenience are the major issues confronting contemporary orthodontic practice. Very few studies have been published till date regarding the efficiency of self-ligating brackets as against conventional brackets. Hence, the present study was planned to compare the rate of canine retraction between self-ligating and conventional brackets and to determine the amount of anchorage loss during canine retraction.

METHODS

The present clinical study was designed as a prospective, observational study comprising of 25 patients requiring first premolar extraction as a part of orthodontic treatment. Self-ligating and conventional brackets were bonded using a split-mouth study design randomly. Retraction of canines was done with 150 grams of force using Dontrix gauge with E-chains. The study was conducted in relation to upper arch only, while the rate of retraction was evaluated every 4 weeks for 3 months. Average rates of retraction in 3 months were calculated. For anchorage loss, an acrylic guide plug was used in mid-treatment cast (T0) and after 3 months of retraction (T3). The statistical analysis was done using Statistical Package for Social Sciences (SPSS) version 17.0 (SPSS Inc., Chicago, IL, USA). Independent t-test was used to compare the means of the two variables studied, while Pearson's correlation coefficient was used to evaluate the correlation between the variables studied in the groups included. P < .05 was considered statistically significant.

RESULTS

The correlation coefficient between the average rate of canine retraction with self-ligating brackets vs. conventional brackets over a period of 3 months came out to be 0.6434, while on comparing the data in terms of anchorage loss over a period of 3 months, the respective correlation coefficient value was found to be 0.6659 with the results being statistically highly significant in either case (P < .001).

CONCLUSIONS

Self-ligating brackets showed double the amount of displacement compared to conventional brackets in some of the cases. Also, chair side time was significantly reduced with self-ligating brackets as against conventional brackets.

Mesial movement of maxillary first molars and vertical dimensional changes in orthodontic extraction treatment for patients with different facial morphology

Objectives: Primarily, to compare anchorage loss and changes in mandibular plane (MP) angle, overbite, and amount of horizontal, vertical, and angular movements of maxillary incisors in groups of hypodivergent, hyperdivergent, and normodivergent patients. Secondarily, to analyze the relationship between those factors. Methods: Pre- and post-treatment cephalograms of 89 patients treated with extraction of four bicuspids or two maxillary bicuspids were analyzed. The sample was divided into three groups based on their facial pattern measured by SN-MP angle (hypodivergent: < 270, hyperdivergent: >380, and normodivergent: 270-380). Linear and angular measurements included the distances of U1 tip and U6 mesial height of contour to Y-axis (i.e., line perpendicular to the X-axis, passing through Sella turcica), distance of U1 tip to Sella on X-axis, overbite, angulation of U1 to palatal plane, and SN-MP and ANB angles. Inferential statistics included one-way ANOVA, Chi-square test, independent t-test, and Pearson’s correlation coefficients. Results: Facial morphology did not primarily affect anchorage loss, because other factors such as crowding, severity of Class II molar relationship, and extraction modality played more impactful role (P< 0.01). Change in mandibular plane angle was neither influenced by, nor correlated with, initial facial morphology or anchorage loss (P> 0.05). Positive change in overbite was significantly correlated with facial pattern, incisor extrusion and retroclination (r= 0.30, 0.44, and -0.35, respectively, P< 0.01). Conclusion: Anchorage loss in extraction orthodontic treatment is not influenced primarily by initial facial morphology. Anchorage loss is not significantly associated with MP angle reduction. Change in overbite can be achieved through incisor extrusion and retroclination.

Von Mises stresses on Mushroom-loop archwires for incisor retraction: a numerical study

OBJECTIVE

To perform a numerical simulation using FEM to study the von Mises stresses on Mushroom archwires.

METHODS

Mushroom archwires made of titanium-molybdenum alloy with 0.017 x 0.025-in cross-section were used in this study. A YS of 1240 MPa and a Young's modulus of 69 GPa were adopted. The archwire was modeled in Autodesk Inventor software and its behavior was simulated using the finite element code Ansys Workbench (Swanson Analysis Systems, Houston, Pennsylvania, USA). A large displacement simulation was used for non-linear analysis. The archwires were deformed in their extremities with 0° and 45°, and activated by their vertical extremities separated at 4.0 or 5.0 mm.

RESULTS

Tensions revealed a maximum of 1158 MPa at the whole part of the loop at 5.0mm of activation, except in a very small area situated at the top of the loop, in which a maximum of 1324 Mpa was found.

CONCLUSIONS

Mushroom loops are capable to produce tension levels in an elastic range and could be safely activated up to 5.0mm.

Comparison of anchorage loss between conventional and self-ligating brackets during canine retraction - A systematic review and meta-analysis

INTRODUCTION

Anchorage is defined as the resistance to unwanted tooth movement. In orthodontics, loss of anchorage can be detrimental to treatment. The proponents of orthodontic self-ligating brackets (SLB) advocate the use of extremely light forces thereby reducing anchorage burden. Therefore, the aim of this study was to compare anchorage loss during canine retraction between conventional brackets (CB) and self-ligating brackets.

METHODS

An electronic search was conducted on the Cochrane database, Scopus, Web of Science, PubMed, Dental & Oral Science and CINAHL, along with handsearching Google Scholar and clinicaltrials.gov. Randomized or non-randomized clinical trials published in the English language on human subjects were included. Orthodontic patients undergoing canine retraction after premolar extraction bonded with self-ligating brackets as the intervention and conventional brackets as the control group in a split mouth design were included. Primary outcome studied was anchorage loss; secondary outcomes were retraction velocity and total amount of canine retraction. Two researchers carried out data extraction and study selection independently. The risk of bias was calculated using the Cochrane's Risk of Bias Assessment tool. The RevMan software was used for quantitative synthesis of data. Effect estimate of the primary and secondary outcomes was expressed using weighted mean difference and 95% confidence intervals (CIs). Heterogeneity of the studies was evaluated using the Cochrane's test for heterogeneity (I² Test); subgroup and sensitivity analyses were performed to investigate sources of heterogeneity among the studies.

RESULTS

Results of the literature search across all databases yielded 10,439 hits, out of which five studies were included in the qualitative synthesis that met the inclusion criteria. Four studies were randomized control trials (RCTs) where as one was a non-randomized control trial, with 100 subjects included in this systematic review. All studies used a split mouth design. Of the five studies included, only one reported significant differences between CB and SLB for anchorage loss, retraction velocity and total amount of canine retraction (P-value≤0.001). Four studies were included in the meta-analysis, which showed no difference in the amount of anchorage between self-ligating and conventional brackets (weighted mean difference - 0.22; 95% CI [-0.82, 0.38]; P=0.48). Multiple subgroup analyses further revealed there were no significant differences between the intervention and control groups for all outcomes studied.

CONCLUSION

This systematic review and meta-analysis found insufficient evidence to suggest a significant difference in anchorage loss between the CB and SLB groups. The scarcity of current evidence dictates that further studies are needed to canonically establish the clinical superiority of one over the other.

REVIEW REGISTRATION

PROSPERO 2019 CRD42019133217.

Does anchorage loss differ with 0.018-inch and 0.022-inch slot bracket systems?

OBJECTIVES

To compare maxillary first molar anchorage loss between 0.018-inch and 0.022-inch slot fixed appliance systems.

MATERIALS AND METHODS

Patients requiring bilateral maxillary premolar extractions (n = 74) within a randomized clinical trial comparing the effectiveness of 0.018-inch and 0.022-inch slot MBT bracket systems (3M-Unitek, Monrovia, Calif) were included. Three-dimensional pre- and posttreatment digital models were landmarked and measured (R700 scanner and OrthoAnalyzer software, 3Shape, Copenhagen, Denmark). Anteroposterior position of the first molars was measured using the third medial rugae point as a reference. Anchorage loss (AL) represented the subtraction of the posttreatment distance from the pretreatment distance for both anchorage loss right (ALR) and left (ALL) sides. The values were then compared using a two-way analysis of variance.

RESULTS

There were 41 and 33 cases for the 0.018-inch and 0.022-inch bracket slot systems, respectively. The baseline characteristics were similar between groups, except for the presence or absence of anchorage devices (P = .050). For the total sample: 0.018-inch ALR = 3.86 mm, ALL = 3.30 mm and 0.022-inch ALR = 3.73 mm, ALL = 3.47 mm (P = .970). There was also no significant difference between the 0.018-inch and 0.022-inch groups when subjects with anchorage devices were excluded (P = .383).

CONCLUSIONS

Bracket slot size does not influence maxillary molar anchorage loss during orthodontic treatment.

Efficacy of orthodontic mini implants for en masse retraction in the maxilla: a systematic review and meta-analysis

Background/aim

Retraction of the upper incisors/canines requires maximum anchorage. The aim of the present study was to analyze the efficacy of mini implants in comparison to conventional devices in patients with need for en masse retraction of the front teeth in the upper jaw.

Material and methods

An electronic search of PubMed, Web of Science, and EMBASE and hand searching were performed. Relevant articles were assessed, and data were extracted for statistical analysis. A random effects model, weighted mean differences (WMD), and 95% confidence intervals (CI) were computed for horizontal and vertical anchorage loss at the first molars in the analyzed patient treatments.

Results

A total of seven RCTs employing direct anchorage through implants in the alveolar ridge were finally considered for qualitative and quantitative analysis, and further five publications were considered for the qualitative analysis only (three studies: indirect anchorage through implant in the mid-palate, two studies: direct/indirect anchorage in the alveolar ridge). In the control groups, anchorage was achieved through transpalatal arches, headgear, Nance buttons, intrusion arches, and differential moments.

WMD [95% CI, p] in anchorage loss between test and control groups amounted to − 2.79 mm [− 3.56 to − 2.03 mm, p < 0.001] in the horizontal and − 1.76 mm [− 2.56 to − 0.97, p < 0.001] favoring skeletal anchorage over control measures. The qualitative analysis revealed that minor anchorage loss can be associated with indirect anchorage, whereas anchorage gain was commonly associated with direct anchorage. Implant failures were comparable for both anchorage modalities (direct 9.9%, indirect 8.6%).

Conclusion

Within its limitations, the meta-analysis revealed that maximum anchorage en masse retraction can be achieved by orthodontic mini implants and direct anchorage; however, the ideal implant location (palate versus alveolar ridge) and the beneficial effect of direct over indirect anchorage needs to be further evaluated.

Electronic supplementary material

The online version of this article (10.1186/s40729-018-0144-4) contains supplementary material, which is available to authorized users.

Aggravation of Gummy Smile by Straight-Wire Mechanics and its Management with or without Orthognathic Surgery Up to 10-Year Follow-Up

Two female patients presented with gummy smile, maxillary dentoalveolar protrusion and total vertical maxillary excess, retroclined incisors, and increased overbite received orthodontic camouflage with straight-wire mechanics by general dentists. The treatments caused severe bowing of upper occlusal plane which aggravated the gummy smile and had led them to seek specialist care. They were successfully managed by orthodontic camouflage and combined surgical-orthodontic treatment, respectively, in conjunction with the application of miniscrews on straight-wire mechanics. Aggravation of gummy smile by straight-wire mechanics, use of visual treatment objective to differentiate between orthodontic camouflage and surgical cases, and LeFort I segmentalization were discussed.

[Not Available]

Le Pr Ravindra Nanda a obtenu une licence et une maîtrise en dentisterie et en orthodontie du King George's Medical College, Lucknow University. En 1967, il a intégré l'Université Catholique de Nimègue, aux Pays-Bas, où il a obtenu un doctorat en philosophie en 1969. Il a rejoint la nouvelle école dentaire de Loyola à Chicago en 1970, après avoir occupé le poste de Professeur assistant en orthodontie dans le service dirigé par Frans van der Linden. En 1972, il fut promu au Département d'Orthodontie de l'Université du Connecticut à Farmington, CT, et y reçu son certificat en orthodontie sous la direction de Charles Burstone. Professeur adjoint, puis professeur titulaire à partir de 1979, il a assumé le poste de Chef du Département d'Orthodontie à partir de 1992 et a été promu pour diriger le Département des Sciences Craniofaciales en 2004, dont les divisions de chirurgie orale et maxillo-faciale, de dentisterie pédiatrique, de l'enseignement supérieur en dentisterie générale et en orthodontie.

Il est membre et ancien président de la composante Atlantique Nord de la Edward H. Angle Society of Orthodontists. Il occupe actuellement la fonction de rédacteur en chef de Progress in Orthodontics, de rédacteur associé du Journal of Clinical Orthodontics et est membre du comité éditorial de neuf revues d'orthodontie nationales et internationales. Il est membre de l'Association dentaire américaine, de l'Association dentaire de l'État du Connecticut, de la Hartford Dental Society, de l'Association américaine des orthodontistes, de la Société européenne d'orthodontie, de l'Association internationale de recherche dentaire et du College of Diplomates of American Board of Orthodontists.

Il a rédigé et publié sept manuels et plus de 200 articles dans des revues à comité de lecture. Il a donné des conférences magistrales dans plus de 40 pays et a reçu de nombreux prix et honneurs pour ses contributions en dentisterie et en orthodontie, aux États-Unis et de la part d'organisations internationales d'orthodontie. Il est membre d'honneur des Jordan Orthodontic Society, Czech Orthodontic Society, Taiwanese Orthodontic Society, Central American Orthodontics Society et membre d'honneur à vie de l'Indian Orthodontic Society.

Ravindra Nanda a été honoré du Life Time Achievement Award (University of Connecticut Foundation), et il est Senior Research Fellow (Japan Promotion for Science, Sendai, Japan − Tohoku University). Il a prononcé de nombreuses conférences d'honneur : la John Taylor Lecture, lors de la réunion annuelle de l'Australian Society of Orthodontics Foundation, la Sheldon Friel Memorial Lecture lors de la réunion annuelle de l'European Orthodontic Society, la Gordon Kirkness Memorial Lecture lors de la réunion annuelle de l'Australian Society of Orthodontics, la John Mershon Memorial Lecture, Boston, Massachusetts lors de la réunion annuelle de l'American Association of Orthodontics et la Wendell L. Wylie Memorial Lecture, à l'Université de San Francisco, Californie.

Collapse

A comparison of lower canine retraction and loss of anchorage between conventional and self-ligating brackets: a single-center randomized split-mouth controlled trial

OBJECTIVE

To evaluate the rate of lower canine retraction, anchorage loss, and changes on lower canines and first molars axial inclination using self-ligating and conventional brackets.

MATERIALS AND METHODS

Twenty-five adult patients with a treatment plan involving extractions of four first premolars were selected for this split-mouth trial and had either conventional or self-ligating brackets bonded to lower canines in a block randomization. Retraction was accomplished using 100-g nickel titanium closed-coil springs, which were reactivated each 4 weeks. Oblique radiographs were taken before and after total canine retraction and the cephalograms were superimposed on stable structures of the mandible. Cephalometric points were digitized twice by a single-blinded operator for error control and the average of the points were used to determine the following variables: canine cusp horizontal changes, molar cusp horizontal changes, and angulation changes in canines and molars. Paired t tests were used to analyze the blinded data for group differences.

RESULTS

All patients reached final phase without bracket debonds. No differences were found between the two groups for all variables tested. No serious harm was observed.

CONCLUSION

Both brackets showed the same rate of canine retraction and loss of anteroposterior anchorage of the molars. No changes were found between brackets regarding the inclination of canines and first molars.

CLINICAL RELEVANCE

Using self-ligating brackets to retract lower canines will not increase the velocity of tooth movement, does not increase anchorage, and does not decrease tipping.

Anchorage condition during canine retraction using transpalatal arch with continuous and segmented arch mechanics

OBJECTIVE

To compare anchorage condition in cases in which transpalatal arch was used to enhance anchorage in both continuous and segmented arch techniques.

MATERIALS AND METHODS

Twenty cases that required first premolar extraction for orthodontic treatment and transpalatal arch to enhance anchorage were included in this study. Ten cases were treated using the continuous arch technique, while the other 10 cases were treated using 0.019 × 0.025-inch TMA T-loops with posterior anchorage bend according to the Burstone and Marcotte description. Lateral cephalometric analysis of before and after canine retraction was performed using Ricketts analysis to measure the anteroposterior position of the upper first molar to the vertical line from the Pt point. Data were analyzed using an independent sample t-test.

RESULTS

There was a statistically significant forward movement of the upper first molar in cases treated by continuous arch mechanics (4.5 ± 3.0 mm) compared with segmented arch mechanics (-0.7 ± 1.4 mm; P  =  .01).

CONCLUSIONS

The posterior anchorage bend to T-loop used to retract the maxillary canine can enhance anchorage during maxillary canine retraction.

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.

Canine retraction and anchorage loss: self-ligating versus conventional brackets in a randomized split-mouth study

OBJECTIVE

To evaluate the velocity of canine retraction, anchorage loss and changes on canine and first molar inclinations using self-ligating and conventional brackets.

MATERIALS AND METHODS

Twenty-five adults with Class I malocclusion and a treatment plan involving extractions of four first premolars were selected for this randomized split-mouth control trial. Patients had either conventional or self-ligating brackets bonded to maxillary canines randomly. Retraction was accomplished using 100-g nickel-titanium closed coil springs, which were reactivated every 4 weeks. Oblique radiographs were taken before and after canine retraction was completed, and the cephalograms were superimposed on stable structures of the maxilla. Cephalometric points were digitized twice by a blinded operator for error control, and the following landmarks were collected: canine cusp and apex horizontal changes, molar cusp and apex horizontal changes, and angulation changes in canines and molars. The blinded data, which were normally distributed, were analyzed through paired t-tests for group differences.

RESULTS

No differences were found between the two groups for all variables tested.

CONCLUSIONS

Both brackets showed the same velocity of canine retraction and loss of anteroposterior anchorage of the molars. No changes were found between brackets regarding the inclination of canines and first molars.