Comparison of rate of canine retraction with conventional molar anchorage and titanium implant anchorage

Innovative Treatment Approach: Multiple Variability (MV) Loop Intervention for Angle Class I Malocclusion with Dewey's Type 2 Modification: A Case Report

Proclination of anteriors is significantly found in developing malocclusions and affecting both aesthetics and function. In patients with protrusions or crowding, extraction therapy is often necessary. Orthodontic treatment is initiated with the extraction of maxillary first premolars to address the protrusions or crowding and achieve a harmonious occlusion. There are two ways to retract anteriors during extraction space closure: friction or frictionless. The present case report explains the innovative treatment approach for the correction of anterior protrusion using multiple variability (MV) loops. Even with the good efficiency of the MV loop, meticulous wire bending is one of the disadvantages of the loop, and it requires clinician skills. Smaller loop fabrication will be the future scope of the appliance to increase patient compliance toward the treatment using MV loop as it will cause less hindrance in the vestibular region.

Tooth movement with dental anchorage vs. skeletal anchorage: A systematic review of clinical trials

The aim of this study is to compare the time and movement of orthodontic treatment using dental anchorage and skeletal anchorage in adolescent and adult patients with dental malocclusions. A systematic search was conducted in the Embase, PubMed, Lilacs, Cochrane, Trip, and Scopus databases up to October 2022. All the articles were selected using title and abstract, applying the inclusion and exclusion criteria. Disagreements were resolved with a third author. Finally, a full-text selection took place. The data extraction was conducted by two authors who independently evaluated the risk of bias. The methodological quality of the randomized clinical trials was evaluated using the Cochrane tool for the evaluation of the randomized clinical trials. Six articles were included in the data analysis. There were four clinical trials and two randomized clinical trials. A total of 176 patients was obtained with an age range between 14 and 46 years. Four studies showed significant differences when comparing the two anchorages in retraction or distalization of tooth groups, and two showed no differences when using dental and skeletal anchorage for vertical movements; only the articles with vertical movements showed relapse. We can conclude that skeletal anchorage generates precise and stable horizontal movements without overloading or changing the position of the molar. Future studies must incorporate three-dimensional technology for greater clinical accuracy.

Evaluation of maxillary canine and molar movement during the first phase of extraction space closure: a multilevel analysis

OBJECTIVE

This study was designed to analyze and compare the cusp and apex movements of the maxillary canines and first molars during canine retraction in the first step of extraction space closure, and to evaluate if these teeth follow a curvilinear (acceleration and/or deceleration) movement rate.

MATERIAL AND METHODS

Twenty-five patients (23.3 ± 5.1 years of age) were enrolled. The retraction of the maxillary canines was accomplished using nickel-titanium closed coil springs (100gf) on 0.020-in stainless steel archwire. Oblique cephalograms were traced and superimposed on the anatomic best fit of the maxilla (before the retraction [T0], and after one month [T1], three [T3], five [T5] and seven [T7] months). Statistics was based in a normally distributed data. Multilevel procedures were used to derive polynomials for each of the measurements. Student's t-test and one-way repeated measures ANOVA were conducted. The level of significance of 5% was adopted.

RESULTS

Canine cusps and apexes did not follow a quadratic curve regarding horizontal movement (neither accelerate nor decelerate). Canine and molar cusps showed more horizontal movement than apexes (4.80 mm vs. 2.78 mm, and 2.64 mm vs. 2.17 mm, respectively).

CONCLUSIONS

Canine did not accelerate or decelerate overtime horizontally; the cusps and apexes of the canines and molars showed more horizontal movement and larger rate at the beginning of canine retraction, followed by significantly smaller and constant movement rate after the first month.

Dentoalveolar and Soft Tissue Changes Following en-Masse Anterior Retraction With Different Force Vectors in Subjects With Bidental Protrusion: A Retrospective Evaluation

Introduction The aim of the study is to determine the effects of different vertical force vectors acting on dentoalveolar and soft tissues while applying a retraction force using various anchorage sources and their effects on these tissues. Material and methods Based on the selection criteria, a total of 35 patient case records with Angle's Class I bidental malocclusion and incompetent lips treated with four premolar extractions were included. Retraction was achieved using a NiTi coil spring with two different force vectors. The anchorage in group 1 was enhanced by a transpalatal arch (TPA) and Lower Stabilizing Arch (LSA) in the upper and lower arch, respectively, with a force vector parallel to the occlusal plane, whereas in group 2, the force vector using Temporary Anchorage Devices (TADs) was 15 - 20 degrees to the occlusal plane. The skeletal, dental, and soft tissue were obtained using 40 parameters. Intra-group comparisons between pre- and post-treatment records were conducted using a paired t-test, while inter-group comparisons were conducted using an independent t-test. Result Significant anchor loss was observed in group 1, indicated by mesial movement of molar crowns by (-2.10±0.50) in the maxillary arch and (-1.75±0.38) in the mandibular arch. Distal movement of incisors following premolar extractions with both studied force vectors resulted in an improvement in lip procumbency and incisor inclinations, without any significant skeletal changes. Molar mesial movement was observed in subjects treated with conventional anchorage. Conclusion En masse anterior retraction did lead to anchorage loss when carried out without TADs. Altering the force vector did not produce significant changes in tooth movement along the vertical plane.

Methods of measuring distal canine movement and rotation- A review

This article provides an overview of the various methods for measuring distal canine movement and rotation during retraction. Various databases, including PubMed Central, Science Direct, Wiley Online Library, the Cochrane Library, Textbooks, Google Scholar, and Research Gate, and a manual search up until September 2022, were used to search for various methods of measuring distal canine movement and rotation during retraction. After excluding the duplicate articles, the papers explaining these techniques were included. Four significant techniques were identified. The digital method with 3D superimposition is the safest, most accurate, and most accessible of the methods reviewed.

Reducing relapse and accelerating osteogenesis in rapid maxillary expansion using an injectable mesoporous bioactive glass/fibrin glue composite hydrogel

Rapid maxillary expansion (RME), as a common treatment for craniomaxillofacial deformity, faces the challenge of high relapse rates and unsatisfactory therapeutic effects. In this study, a standardized Sprague-Dawley (SD) rat RME model was first established with a modified expander as well as retainer design and optimized anterior maxillary expanding force of 100 g which exerted the most synchronized mobility of mid-palatal suture and incisors. Via the standardized model, the high relapse rate was proven to be attributed to insufficient osteogenesis in expanded suture, requiring long-term retainer wearing in clinical situations. To reduce the relapse rate, mesoporous bioactive glass/fibrin glue (MBG/FG) composite hydrogels were developed for an in situ minimal invasive injection that enhance osteogenesis in the expanded palate. The component of 1 wt% MBG was adopted for enhanced mechanical strength, matched degradation rate and ion dissolution, excellent in vitro biocompatibility and osteoinductivity. Effects of 1%MBG/FG composite hydrogel on osteogenesis in expanded mid-palatal sutures with/without retention were evaluated in the standardized model. The results demonstrated that injection of 1%MBG/FG composite hydrogel significantly promoted bone formation within the expanded mid-palatal suture, inhibited osteoclastogenesis and benefited the balance of bone remodeling towards osteogenesis. Combination of retainer and injectable biomaterial was demonstrated as a promising treatment to reduce relapse rate and enhance osteogenesis after RME. The model establishment and the composite hydrogel development in this article might provide new insight to other craniomaxillofacial deformity treatment and design of bone-repairing biomaterials with higher regenerative efficiency.

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A standardized rat RME model was established with optimized parameters.

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Sufficient osteogenesis was the prerequisite of reducing relapse ratio.

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Design of an injectable MBG/FG composite hydrogel for osteogenic enhancement.

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Combinatory treatment of injection and retention was developed for relapse reduction.

Effect of Frequency of Micro-osteoperforation on Miniscrew- supported Canine Retraction: A Single-centered, Split-mouth Randomized Controlled Trial

AIM

The present study aimed at evaluating the increase in the rate of tooth movement by increasing the number and frequency of micro-osteoperforations (MOPs).

MATERIALS AND METHODS

The study was a single-center, split-mouth, randomized controlled trial. A total of 20 patients were included in the study who had fully erupted maxillary canines with class I molar canine relationship and a bimaxillary protrusion that required the removal of both maxillary and mandibular first premolars. Out of 80 samples, the experimental and controlled groups were randomly assigned. The experimental group received five MOPs in the extracted site of the first premolar before retraction, at 28th day and 56th day. The control group received no MOPs. The rate of tooth movement was measured on 28th, 56th, and 84th day on both the experimental and control sides.

RESULTS

In maxillary dentition, the canine on the MOP side moved by 0.65 ± 0.21 mm, 0.74 ± 0.23 mm, and 0.87 ± 0.27 mm during 28th, 56th, and 84th day, respectively, whereas in control side the rate of tooth movement was 0.37 ± 0.09 mm, 0.43 ± 0.11 mm, and 0.47 ± 0.11 mm during 28th, 56th and 84th day, respectively, which was statistically significant (p-value = 0.000). In mandibular dentition, the canine on the MOP site has moved by 0.57 ± 0.12 mm, 0.68 ± 0.21 mm, and 0.67 ± 0.10 mm during 28th, 56th, and 84th day, respectively, whereas in control side the rate of the tooth movement was 0.34 ± 0.08 mm, 0.40 ± 0.15 mm, and 0.40 ± 0.13 mm during 28th, 56th, and 84th day, respectively, which was statistically significant.

CONCLUSION

Micro-osteoperforations effectively increased the rate of tooth movement. Overall, MOPs increased the rate of canine retraction by 2-fold when compared with the control group.

CLINICAL SIGNIFICANCE

Micro-osteoperforation is a proven methodology to increase the rate of tooth movement and decrease the treatment time. However, it is important to repeat the procedure during every activation to increase its effectiveness.

Canine root/cortical bone relation (CRCR) and the orthodontic tooth movement

This observational study evaluates three-dimensionally the relation between the root of maxillary canine and overlying labial cortical plate of bone during orthodontic canine retraction. Eighty-four bilateral maxillary canines in 42 patients were retracted in the extraction space of first premolars, using conventional orthodontic NiTi retraction spring delivering 150gm. Three-dimensional evaluation at the cusp tip, root apex, and the overlying cortical bone was done based on Classification of Root/Cortical bone relation (CRCR) before and after canine retraction. 168 observations of the canines pre- and post-retraction showed a mean distal movement of the canine cusp tip of 3.78(± 2.05) mm, while the canine root apex was almost stationary. Scarcely, 5.4% of the canine roots and root apices persisted in the medullary bone during retraction, while 16.1% contacted the overlying cortical bone. Fenestration of the overlying cortical bone by the canine roots or root apices occurred in 78.6% of the sample. The unembellished intimacy between the canine root and apex to the overlying thick dense cortical bone might have the decelerating effect on the maxillary canine retraction. The natural bone plate labial to the maxillary canine root did not yield infront nor enlarge due to canine retraction, but else defeated the current orthodontic biomechanical implementation.

Comparison of mean canine retraction between healed and recently extracted site: A single center, randomized control trial

Objectives:

The objective of this “2-arm parallel” trial was to compare mean canine retraction into healed and recently extracted site.

Materials and Methods:

One of the sides of the maxillary dental arch of the patients having undergone orthodontic treatment at orthodontic department of a private hospital was randomly allocated to recent extraction side, while the contra-lateral side to healed extraction site. Eligibility criteria included no active local or systemic diseases including long-term medications. The main outcome was canine retraction into the extraction sites. Simple randomization technique was used allocate the right and left sides of the arch to one of the groups with allocation concealment through sequentially numbered, opaque, and sealed envelopes. Blinding was applicable for outcome assessor only. The patients were reviewed after 1 month of retraction. Data were analyzed on an intention to treat basis, using paired t-test was applied to compare the canine retraction between healed and recently extracted site (P ≤ 0.05 statistically significant).

Results:

Thirty-five patients with a mean age of 17.6 years were randomized in a 1:1 ratio for one of the sides of the arch to either recent extraction site or healed extraction site. After a month active retraction in 32 patients, the canine at recent extraction site moved 1.17 ± 0.27 mm in 1 month and 0.75 ± 0.26 mm in 1 month on the healed extraction site (P = 0.00). Two patients were lost to follow-up. No harm was observed.

Conclusion:

The results of the study indicate that the mean canine retraction was faster into the recent extraction site. The mean difference of 0.45 mm between the two sides was found be statistically significant.

Total maxillary arch distalization by using headgear in an adult patient

Although headgear is rarely used in adult patients, its use in adults is mainly for anchorage control. In the current case report, a 24-year-old patient had a skeletal Class I relationship with a Class II tendency, brachyfacial pattern, significant facial asymmetry, and dental 3/4 cusp Class II molar and canine relationships on both sides. The patient declined surgery, and facial asymmetry was not his concern. The final treatment goal was to achieve a stable Class I dental relationship and normal occlusion without significantly compromising the patient's profile. The patient was compliant with the use of cervical-pull headgear after he refused the options of orthodontic-orthognathic combined treatment, maxillary premolar extraction, or temporary skeletal anchorage mini-implants. A 5-mm maxillary arch distal movement was accomplished without significant distal tipping of the molar crowns. The active treatment duration was 31 months. Proper overbite and overjet, balanced occlusion, and an acceptable facial profile were achieved. The treatment results inspire reconsideration of the possibility of using headgear in dental Class II correction in adult patients.

A clinical comparative study using anchorage from mini-implants and conventional anchorage methods to retract anterior teeth

Background:

Proclined teeth has been one of the main reasons for compromised esthetics. In a patient with proclined anteriors, retraction is done after 1^st premolar extraction. Absolute/maximum anchorage is required to achieve the best esthetics.

Objective:

We conducted this study with the aim of retracting the proclined maxillary anterior teeth and to check for efficient retraction, type of tooth movement during retraction, and amount of anchorage loss.

Methods:

Patients with proclined anterior teeth where therapeutic extraction of first premolars is required were included in the study, where anchorage was taken with mini-implants in one group, and in the second group, conventional anchorage method of 1^st and 2^nd molar banding with TPA was chosen. Each group consisted of 8 subjects. Lateral cephalogram was taken both preretraction and 4 months after starting retraction to compare anchor loss, rate of retraction, and type of tooth movement of retracted anteriors, in both groups.

Results:

The retraction in the implant group was more than in the conventional group and the difference was statistically significant (P < 0.05). Anchorage loss was seen to be greater in conventional group than in the implant group and was also significant statistically. The type of tooth movement of the anterior teeth on retraction was also compared, with the implant group showing predominantly controlled tipping and the conventional group showing uncontrolled tipping movement.

Effectiveness of orthodontic temporary anchorage devices in canine retraction and anchorage preservation during the two-step technique: a systematic review and meta-analysis

Background

Temporary anchorage devices have been used for decades in orthodontic practice for many applications. The aim of this systematic review was to assess the effectiveness of orthodontic temporary anchorage devices in canine retraction during the two-step technique.

Methods

A search was systematically performed for articles published prior to June 30, 2019 in five electronic databases (PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus). The risk of bias was assessed using the Cochrane risk of bias tool for randomized controlled trials (RCTs) and the risk of bias in nonrandomized studies of interventions (ROBINS-I) tool for controlled clinical trials (CCTs). The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) approach was used for the quality assessment. Data concerning the mean difference in mesial molar movement and extent of canine retraction were extracted for statistical analysis. The mean differences and 95% confidence intervals were analyzed for continuous data. A meta-analysis with a random-effects model for comparable outcomes was carried out.

Results

Three RCTs and five CCTs were finally included. Meta-analysis showed a significant increase not only in anchorage preservation in the implant anchorage group in both the maxilla (1.56 mm, 95% CI: 1.14 to 1.98, P < 0.00001) and the mandible (1.62 mm, 95% CI: 1.24 to 2.01, P < 0.00001) but also in canine retraction in the implant anchorage group in both the maxilla (0.43 mm, 95% CI: 0.16 to 0.69, P = 0.001) and the mandible (0.26 mm, 95% CI: 0.02 to 0.49, P = 0.03).

Conclusions

There is very low-quality evidence showing that implant anchorage is more efficient than conventional anchorage during canine retraction. Additional high-quality studies are needed.

Comparison of the Anchorage Value of the First Molars Supported with Implant and First Molars Supported with Second Molar during En Masse Retraction

Aims and Objectives:

The aim of this study was to determine the efficacy of mini-implants as adjuncts for intraoral anchorage units for en masse retraction of maxillary anterior teeth in bimaxillary dentoalveolar protrusion cases.

Materials and Methods:

The study sample consisted of 15 patients (10 females and 5 males). The samples were compared for anchorage loss with the implant-supported molar and conventional molar contralaterally in both the maxilla and mandible after six months of retraction period. The mini-implants used were 1.5 mm in diameter and 8 mm in length and were inserted in the first and third quadrant between the roots of second premolar and first molar under local anesthesia at an angle of 45°. For en masse retraction, active tiebacks with ligating (100g) were used bilaterally extending from molar hooks to J-hook on a 0.019” × 0.025” stainless steel arch wire. Lateral cephalograms were taken before and after retraction for assessing the loss of anchorage in maxillary and mandibular first molars.

Results:

Anchorage loss of 1.46 mm in the maxilla and 1.36 mm in mandible was found with conventional molar anchorage, whereas no statistically significant anchorage loss was found in the implant-supported molar side.

Conclusion:

Implant-supported molar side showed better anchorage compared with the conventional molar side. Hence, implant-supported molar can be used as an absolute anchorage unit in the en masse retraction of anterior teeth.

Soft Tissue Changes in Patients With Dentoalveolar Protrusion Treated With Maximum Anchorage: A Systematic Review and Meta-analysis

OBJECTIVE

This meta-analysis aimed at comparing the angular and linear changes of soft tissue profile using conventional anchorage techniques and mini-implant (MI)-based space closure in patients with dentoalveolar protrusion.

MATERIALS AND METHODS

Electronic databases, viz. PubMed, Embase, and Cochrane Central Register of Controlled Trials, were searched for relevant literature from their inception to December 2017 according to the specific inclusion and exclusion criteria. The following Medical Subject Heading terms were used for searching: "skeletal anchorage", "temporary anchorage devices", "miniscrew implant", "mini-implant", "micro-implant". Selected randomized control trials (RCTs) were assessed for their quality using Cochrane's Risk of Bias Tool, whereas the Newcastle-Ottawa scale was used for non-RCTs. Standardized mean difference (SMD) and 95% confidence interval (CI) were obtained with either fixed- or random-effects models based on the heterogeneity of the included studies.

RESULTS

A total of 5 articles (2 RCTs with moderate risk of bias and 3 high-quality non-RCT studies) were included in the final analysis. The nasolabial angle had significantly greater changes in the MI group than in the conventional anchorage group (SMD = 0.68, 95% CI = 0.39 to 0.97, P < .0001). Significantly higher retraction of the upper lip was seen in the MI group than in the conventional group (SMD = -0.51, 95% CI = -0.84 to -0.18; P = .002). No significant difference was seen in the facial convexity (SMD = -0.34, 95% CI = -0.76 to 0.07, P = .106) and lower lip retraction (SMD = 0.28, 95% CI = -1.72 to 2.28, P = .784) between the groups.

CONCLUSION

It was seen that MIs facilitated favorable soft tissue profile than the conventional anchorage devices. However, more high-quality studies are warranted to confirm the clinical effectiveness of MIs.

Comparison of movement rate with different initial moment-to-force ratios

INTRODUCTION

The objective of this clinical prospective study was to evaluate the effect of the 2 treatment strategies, translation or controlled tipping, followed by root correction on canine retraction efficiency, specifically canine movement rate.

METHODS

Twenty-one patients who needed bilateral maxillary canine retraction to close extraction space as part of their treatment plan were selected for this study. Segmental T-loops designed for controlled tipping or for translation were applied randomly to each side. Two digital maxillary dental casts (taken before and after treatment) were used to measure the tooth displacements of each patient. The coordinate system located at the center of canine crown on the pretreatment model with the 3 axes defined in the mesial-distal (M-D), buccal-lingual, and occlusal-gingival directions was used to express the 6 tooth displacement components. The movement rates on the occlusal plane and in the M-D direction were computed. Movement rates were calculated by dividing the M-D displacements or the resultant displacement on the occlusal plane with the corresponding treatment time.

RESULTS

T-Loops for controlled tipping moved canines faster (33.3% on occlusal plane and 38.5% in the M-D direction) than T-loops for translation. The differences were statistically significant (P = 0.041 on the occlusal plane and 0.020 in the M-D direction).

CONCLUSIONS

Moment-to-force ratio (M/F) affects the canine movement rate in a maxillary canine retraction treatment with the use of a segmented T-loop mechanism. Within the neighborhood of the ratio for translation, lower M/F moves the canine faster than higher M/F both on the occlusal plane and in the M-D direction.

Tooth extractions in Orthodontics: first or second premolars?

Tooth crowding and protrusions demand rigorous attention during orthodontic planning that includes the extraction of first and second premolars. Some characteristics, such as dentoalveolar bone discrepancies, maxillomandibular relations, facial profile, skeletal maturation, dental asymmetries and patient cooperation, are important elements of an orthodontic diagnosis. This study discusses the options of treatments with extractions and describes the correction of a Class I malocclusion, bimaxillary protrusion, severe anterior crowding in both dental arches and tooth-size discrepancy, using first premolar extractions.

Effectiveness of electric toothbrush as vibration method on orthodontic tooth movement: a split-mouth study

Objective:

To investigate the effects of application of vibratory stimuli, using an electric toothbrush, on the rate of orthodontic tooth movement during maxillary canine retraction.

Methods:

A split-mouth study was conducted in 28 subjects (mean age = 20.8 years; ranging from 18 to 24 years) whose bilateral maxillary first premolars were extracted with subsequent canine retraction. On the Vibration side, light force (100 g) was applied to the canine for 90 days, in combination with vibratory stimuli provided by an electric toothbrush; only orthodontic force was applied to the canine on the non-vibration side. Amount of canine movement was measured monthly. Related to electronic toothbrush usage, a diary was provided to each patient for recording discomfort during experimental period, having 100-mm visual analogue scale (VAS). The paired t-test was used to assess the differences in amount of tooth movement between canines of the vibration and non-vibration sides.

Results:

The amount of tooth movement was similar for canines on the vibration side and on the non-vibration side (mean 0.81 ± 0.10 mm and 0.82 ± 0.11 mm, respectively, p> 0.05). Plaque accumulation was minimal in any subject throughout the study. No subject reported discomfort as a result of using the electric toothbrush.

Conclusions:

This study demonstrates that application of vibratory stimuli using an electric toothbrush, in combination with light orthodontic force, do not accelerate orthodontic tooth movement.

Tooth movement rate and anchorage lost during canine retraction: A maxillary and mandibular comparison

OBJECTIVES

To investigate the canine retraction rate and anchorage loss during canine retraction using self-ligating (SL) brackets and conventional (CV) brackets. Differences between maxillary and mandibular rates were computed.

MATERIALS AND METHODS

Twenty-five subjects requiring four first premolar extractions were enrolled in this split-mouth, randomized clinical trial. Each patient had one upper canine and one lower canine bonded randomly with SL brackets and the other canines with CV brackets but never on the same side. NiTi retraction springs were used to retract canines (100 g force). Maxillary and mandibular superimpositions, using cephalometric 45° oblique radiographs at the beginning and at the end of canine retraction, were used to calculate the changes and rates during canine retraction. Paired t-tests were used to compare side and jaw effects.

RESULTS

The SL and CV brackets did not show differences related to monthly canine movement in the maxilla (0.71 mm and 0.72 mm, respectively) or in the mandible (0.54 mm and 0.60 mm, respectively). Rates of anchorage loss in the maxilla and in the mandible also did not show differences between the SL and CV brackets. Maxillary canines showed greater amount of tooth movement per month than mandibular canines (0.71 mm and 0.57 mm, respectively).

CONCLUSIONS

SL brackets did not show faster canine retraction compared with CV brackets nor less anchorage loss. The maxillary canines showed a greater rate of tooth movement than the mandibular canines; however, no difference in anchorage loss between the maxillary and mandibular posterior segments during canine retraction was found.

Comparison of BALP, CTX-I, and IL-4 levels around miniscrew implants during orthodontic tooth movement between two different amounts of force

OBJECTIVES

To evaluate the Interleukin-4 (IL-4), bone-specific alkaline phosphatase (BALP), and C-telopeptide of type I collagen (CTX-I) levels in peri-miniscrew crevicular fluid (PMCF) during orthodontic tooth movement between 75 and 150 g of distalization force.

MATERIALS AND METHODS

Thirty miniscrews were placed bilaterally between the maxillary second premolars and first molars. The right and the left maxillary canines were moved distally using either 75 or 150 g of force. PMCF samples were collected before loading (T0); at 2 hours (T1) and 24 hours (T2) later; and on days 7 (T3), 14 (T4), 21 (T5), 30 (T6), and 90 (T7) after force application. Enzyme-linked immunosorbent assay kits were used to determine BALP, CTX-I, and IL-4 levels.

RESULTS

There was no significant difference between the force groups at all time points with respect to BALP, CTX-I, and IL-4 levels (P > .05). There was no significant difference among time points for the two force groups in terms of BALP and IL-4 levels (P > .05). The CTX-I level at T3 was significantly higher than at T0 for both force groups (P < .05).

CONCLUSIONS

Both 75 g and 150 g of orthodontic force are within optimal force limits, and there is no difference in biochemical markers of bone turnover.

Comparison of anterior retraction and anchorage control between en masse retraction and two-step retraction: A randomized prospective clinical trial

OBJECTIVES

The purpose of this two-arm parallel trial was to compare en masse (ER) and two-step retraction (TSR) during space closure.

MATERIALS AND METHODS

Forty-eight adult patients with bimaxillary protrusion who were planned for treatment with extraction of four first premolars were enrolled. All patients were randomly allocated in a 1:1 ratio to either the ER (n = 24) group or the TSR (n = 24) group. The main outcome was the amount of posterior anchorage loss in the molars and the retraction of the incisors between ER and TSR; the difference in incisor and molar inclination was a secondary outcome. Lateral cephalometric radiographs and oblique cephalometric radiographs at 45° were taken before retraction (T1) and after space closure (T2). Cephalograms were digitized and superimposed on the anatomic best fit of the maxilla and mandible by one operator who was blinded to the treatment group.

RESULTS

Neither incisor nor molar crown movements showed any significant differences between the ER and TSR. There were no significant differences in the tipping of incisors and molars between the two groups.

CONCLUSIONS

No significant differences existed in the amount of retraction of incisors and anchorage loss of molars between ER and TSR. Changes in incisor and molar tipping were similar, with the crowns showing more movement than the apex.

Evaluation of the Effect of Combined Low Energy Laser Application and Micro-Osteoperforations versus the Effect of Application of Each Technique Separately On the Rate of Orthodontic Tooth Movement

AIM

The study was conducted to evaluate the effect of combined low energy laser application and Micro-Osteoperforations versus the effect of the application of each technique separately on the rate of orthodontic tooth movement.

PATIENTS AND METHODS

Three parallel groups (each group contained 10 patients) were performed; Group A: In which one side was controlled side, and the other side received micro-osteoperforations (MOPs), Group B: In which one side was controlled side, and the other side received low-level laser therapy (LLLT), Group C: In which one side was controlled side, and the other side received both MOPs and LLLT.

RESULTS

Significant statistical differences were obvious in the rate of canine retraction between each intervention and the control sides as following; the MOPs increased the rate of canine retraction by 1.6 fold more than the control side, LLLT increased the rate of canine retraction by 1.3 fold than the control side, and combination of both techniques resulted in an increase in the rate of canine retraction by 1.8 fold more than the control side.

CONCLUSION

Combination of MOPs and LLLT proved to be more efficient regarding increasing the rate of canine retraction than the application of each technique separately.

Biochemical and clinical comparisons of segmental maxillary posterior tooth distal movement between two different force magnitudes

Background/objectives

Maxillary tooth distal movement is a treatment option for Class II malocclusion. This prospective clinical study (split-mouth design) was aimed to compare chondroitin sulphate (CS) levels in gingival crevicular fluid (GCF), the rates of tooth movement, and patient pain and discomfort during segmental maxillary posterior tooth distal movement using either 120 or 180 g of retraction force.

Materials and methods

Twenty patients (6 males and 14 females; aged 18.85 ± 4.38 years) with Class II malocclusion were recruited. The force magnitudes were controlled at 120 or 180 g, randomly assigned to either the right or left five-tooth segments. Gingival crevicular fluid samples were collected with Periopaper® strips. Competitive ELISA with monoclonal antibody was used to measure CS levels in GCF. The rates of segmental maxillary posterior tooth distal movement, and the amount of pain and discomfort were evaluated.

Results

The median CS levels during the segmental distal movement period were significantly greater than those before the segmental distal movement period (P < 0.05). At each 1-week period during segmental distal movement, the differences between the median CS levels induced by the two different force magnitudes were not significantly different. The rates of segmental distal movement induced by the two different force magnitudes were not significantly different. The mean visual analog scale scores for pain and discomfort with 180 g of retraction force was significantly greater than that with 120 g (P < 0.05).

Conclusions

One hundred and twenty grams of retraction force was sufficient to cause segmental distal movement, as indicated by biochemically assessed bone remodeling activity and a similar rate of tooth movement to that caused by 180 g of retraction force; it also produced less patient pain and discomfort.

Trial Registration

The study has been registered as TCTR20170728001.

Maxillary incisors changes during space closure with conventional and skeletal anchorage methods: a systematic review

PURPOSE

The objective of this systematic review was to compare the antero-posterior, vertical and angular changes of maxillary incisors with conventional anchorage control techniques and mini-implant based space closure methods.

MATERIALS AND METHODS

The electronic databases Pubmed, Scopus, ISI Web of knowledge, Cochrane Library and Open Grey were searched for potentially eligible studies using a set of predetermined keywords. Full texts meeting the inclusion criteria as well as their references were manually searched. The primary outcome data (linear, angular, and vertical maxillary incisor changes) and secondary outcome data (overbite changes, soft tissue changes, biomechanical factors, root resorption and treatment duration) were extracted from the selected articles and entered into spreadsheets based on the type of anchorage used. The methodological quality of each study was assessed.

RESULTS

Six studies met the inclusion criteria. The amount of incisor retraction was greater with buccally placed mini-implants than conventional anchorage techniques. The incisor retraction with indirect anchorage from palatal mini-implants was less when compared with buccally placed mini-implants. Incisor intrusion occurred with buccal mini-implants, whereas extrusion was seen with conventional anchorage. Limited data on the biomechanical variables or adverse effects such as root resorption were reported in these studies.

CONCLUSION

More RCT's that take in to account relevant biomechanical variables and employ three-dimensional quantification of tooth movements are required to provide information on incisor changes during space closure.

Evaluation of Periodontal Changes Adjacent to Extraction Sites during Upper Canine Retraction

INTRODUCTION

There is an intimate relationship between orthodontic therapy and the periodontal changes that occur during tooth movement.

MATERIALS AND METHODS

This prospective clinical trial aims at investigating the movement of both the free and attached gingiva, as well as the movement of the alveolar bone in the extraction site of the upper 1st premolars during the retraction of the upper canines. In this study, 17 patients (10 female, 7 male) requiring 1st premolar extraction before orthodontic tooth movement were selected and treated at the Department of Orthodontics in the Faculty of Dentistry in University of Hama, Hama, Syria. The upper 1st premolars were extracted, and the implant AutoTacs were applied on the alveolar bone afterward. Then, measurements between the center of the implant AutoTacs and the L-shape wire were taken, utilizing digital Vernier caliper. After 3 weeks of extraction, tattooing marked points were placed on the free and the attached gingival, and the measurements were taken using the same digital Vernier caliper. Closed coil springs made of nickel-titanium were used to retract the upper canines, and a force of 150 gm was applied.

RESULTS

The results of this study showed significant differences between the movement of both the free and attached gingiva and the movement of the corresponding upper canines (p < 0.001). The movement of the free gingiva had formed about 77% of the amount of the movement of the upper canine retraction. No significant differences were detected between the place of implant AutoTac X1 and the L-shaped wire (W) during the retraction of the upper canine. On the contrary, significant differences were noticed between the place of implant AutoTac X2 and the L-shaped wire (W) during the retraction of the upper canine (p < 0.001).

CONCLUSION

There is significant movement of hard and soft tissues during and after premolar extraction and orthodontic therapy.

CLINICAL SIGNIFICANCE

The movement of supporting tissues of the teeth along with the alveolar bone during canine retraction is an important biological characteristic of the orthodontic tooth movement. Clinicians need to understand the role and importance of the supporting tissues during orthodontic treatment, which needs to be incorporated into their routine clinical evaluations.

Effectiveness of the transpalatal arch in controlling orthodontic anchorage in maxillary premolar extraction cases: A systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness of the transpalatal arch (TPA) as an anchorage device in preventing maxillary molar mesialization during retraction of the anterior teeth after premolar extraction.

MATERIALS AND METHODS

This systematic review intended to include patients indicated for upper premolar bilateral extraction and subsequent retraction of anterior teeth, considering the use of TPA as an anchorage tool in one of the treatment groups. The search was systematically performed, up to April 2015, in the following electronic databases: Medline, Embase, and all evidence-based medicine reviews via OVID, Cochrane Library, Scopus, PubMed, and Web of Science. Risk of bias assessment was performed using Cochrane's Risk of Bias Tool for randomized clinical trials (RCTs) and Methodological Index for Nonrandomized Studies (MINORS) for non-RCTs.

RESULTS

Fourteen articles were finally included. Nine RCTs and five non-RCTs presented moderate to high risk of bias. Only one study investigated the use of TPA in comparison with no anchorage, failing to show significant differences regarding molar anchorage loss. A meta-analysis showed a significant increase in anchorage control when temporary anchorage devices were compared with TPA (mean difference [MD] 2.09 [95% confidence interval {CI} 1.80 to 2.38], seven trials), TPA + headgear (MD 1.71 [95% CI 0.81 to 2.6], four trials), and TPA + utility arch (MD 0.63 [95% CI 0.12 to 1.15], 3 trials).

CONCLUSION

Based on mostly moderate risk of bias and with some certainty level, TPA alone should not be recommended to provide maximum anchorage during retraction of anterior teeth in extraction cases.

[A perspective on the use of bone anchorage as opposed to other types of anchorage techniques]

INTRODUCTION

To convert our objectives into the desired treatment results, we need to control our mechanics and thus the anchorage used by avoiding any unwanted movements. It now seems unthinkable, at the dawn of the 21^st century, to ignore the useful contribution of orthodontic screw-borne anchorage. Nevertheless, we are entitled to raise a number of legitimate questions. Do these forms of anchorage offer an alternative to all types of mechanics? Will they permit us to manage clinical situations which are beyond the scope of a more classical approach? Can they enhance the quality of our treatments?

MATERIALS AND METHODS

Each of the authors describes clinical situations using screw-borne anchorage and compares with a conventional approach in order to make a non-exhaustive analysis of the mechanics applied, in their own office, and then highlights the most effective technique.

RESULTS

With 15 years experience in the use of miniscrews, orthodontists have now adopted them with their many advantages as an integral item in their therapeutic armamentarium. However, treatment plans must be coherent. Our mechanics must be well thought-out and represent a cogent entity under the control of the practitioner. Creating screw-borne anchorage demands total control over anchorage stability.

Initial forces experienced by the anterior and posterior teeth during dental-anchored or skeletal-anchored en masse retraction in vitro

OBJECTIVE

To investigate initial forces acting on teeth around the arch during en masse retraction using an in vitro Orthodontic SIMulator (OSIM).

MATERIALS AND METHODS

The OSIM was used to represent the full maxillary arch in a case wherein both first premolars had been extracted. Dental and skeletal anchorage to a posted archwire and skeletal anchorage to a 10-mm power arm were all simulated. A 0.019 × 0.025-inch stainless steel archwire was used in all cases, and 15-mm light nickel-titanium springs were activated to approximately 150 g on both sides of the arch. A sample size of n = 40 springs were tested for each of the three groups. Multivariate analysis of variance (α = 0.05) was used to determine differences between treatment groups.

RESULTS

In the anterior segment, it was found that skeletal anchorage with power arms generated the largest retraction force (P < .001). The largest vertical forces on the unit were generated using skeletal anchorage, followed by skeletal anchorage with power arms, and finally dental anchorage. Power arms were found to generate larger intrusive forces on the lateral incisors and extrusive forces on the canines than on other groups. For the posterior anchorage unit, dental anchorage generated the largest protraction and palatal forces. Negligible forces were measured for both skeletal anchorage groups. Vertical forces on the posterior unit were minimal in all cases (<0.1 N).

CONCLUSIONS

All retraction methods produced sufficient forces to retract the anterior teeth during en masse retraction. Skeletal anchorage reduced forces on the posterior teeth but introduced greater vertical forces on the anterior teeth.

The Effect of Using Self-ligating Brackets on Maxillary Canine Retraction: A Split-mouth Design Randomized Controlled Trial

INTRODUCTION

The results of previous studies about the efficacy of using self-ligating brackets (SLBs) in controlling canine movement during retraction are not in harmony. Therefore, the current study aimed to compare the effects of using new passive SLBs on maxillary canine retraction with sliding mechanics vs conventional ligating brackets (CLBs) tied with metal ligatures.

MATERIALS AND METHODS

The sample comprised 15 adult patients (4 males, 11 females; 18-24 years) requiring bilateral extraction of maxillary first premolars. Units of randomization are the left or right maxillary canines within the same patient. The two maxillary canines in each patient were randomly assigned to one of the two groups in a simple split-mouth design. The canines in the SLBs group (n = 15) were bracketed with SLBs (Damon Q™), while the canines in the CLBs group (n = 15) were bracketed with conventional brackets (Mini Master Series). Transpalatal bars were used for anchorage. After leveling and alignment, 0.019 × 0.025" stainless steel working archwires were placed. Canines were retracted using a nickel-titanium close-coil springs with a 150 gm force. The amount and rate of maxillary canine retraction, canine rotation, and loss of anchorage were measured on study models collected at the beginning of canine retraction (T0) and 12 weeks later (T1). Differences were analyzed using paired-samples t-tests.

RESULTS

The effect differences were statistically significant (p < 0.001). Using Damon Q™ SLBs, the amount and rate of canine retraction were greater, while canine rotation and anchorage loss were less.

CONCLUSION

From a clinical perspective, extraction space closure can be accomplished more effectively using SLBs.

CLINICAL SIGNIFICANCE

Self-ligating brackets gave better results compared to the CLBs in terms of rate of movement, amount of canine rotation following extraction, and anchorage loss.

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.

Efficacy of the Nance appliance as an anchorage-reinforcement method

INTRODUCTION

The Nance appliance is widely considered to be an efficient method of anchorage reinforcement; however, much of the perceived advantage is based on clinical judgment. The aim of this study was to assess the amounts of anchorage loss and desired tooth movement associated with the Nance appliance.

METHODS

The mandibular arches of 7 beagle dogs were used. The first and third premolars were extracted. Reference miniscrews were placed at the first premolar sites as stable references to measure the amounts of anchorage loss and desired tooth movement. Four beagles were fitted with custom-made Nance appliances on the fourth premolars and orthodontic bands on the second premolars (Nance group). Three beagles were fitted with orthodontic bands on the second and fourth premolars with no anchorage reinforcement (control group). The second premolars were retracted over 15 weeks in both groups. The amounts of second premolar movement (desired tooth movement) and fourth premolar movement (anchorage loss) were recorded at 5, 10, and 15 weeks. The percentages of desired tooth movement and anchorage loss to the total space closure were calculated.

RESULTS

The mean desired tooth movement was significantly more in the Nance group than in the control group at 10 weeks (P <0.05) but was not significantly different at 5 and 15 weeks. The mean percentages of anchorage loss to the total space closure at 15 weeks were 45.7% in the control group and 28.8% in the Nance group. The Nance group had 16.9% less anchorage loss and 16.6% more desired tooth movement than did the control group at 15 weeks (P <0.05). Most of the anchorage loss (80%) in the Nance group occurred during the first 10 weeks.

CONCLUSIONS

The Nance appliance did not provide absolute anchorage, but there was significantly less anchorage loss with it than in the control group. The majority of anchorage loss occurred during the first 10 weeks in the Nance group.

Dentate transport discs can be used to reconstruct large segmental mandibular defects

PURPOSE

This study tested the use of a dentate transport segment for the reconstruction of a large U-shaped defect in the anterior segment of the canine mandible using a novel curved reconstruction plate. The quality and quantity of bone regenerate formed by dentate versus edentulous transport segments were compared.

MATERIALS AND METHODS

In 5 adult foxhound dogs, a defect of 70 to 75 mm was created in the canine mandible by excising the mandible anterior to the right and left fourth premolars. Reconstruction was performed by trifocal distraction osteogenesis using a bone transport reconstruction plate (BTRP-02), with 2 transport units being activated simultaneously, one on either side of the defect, 1 dentate and 1 edentulous. Bilateral distraction proceeded at a rate of 1 mm/day until the segments docked against each other in the midline. After 39 to 44 days of consolidation, the animals were euthanized. The quantity and quality of bone regeneration on the 2 sides were compared using micro-computed tomography.

RESULTS

The defect reconstruction was successful. The amount and quality of bone formed by the transport segments were similar on the 2 sides. There were no major differences in the bone volume fraction and density of the regenerate bone formed by the 2 transport segments. The bone volume fraction and density of the regenerate bone were considerably lower than those of the host bone in the distal segments, likely owing to the short consolidation period.

CONCLUSIONS

Bone transport remains a viable option in reconstructing anterior segmental defects in the mandible. The use of dentate or edentulous transport segments for reconstruction provides options for the surgeon in often highly compromised patients requiring these surgeries.

Canine retraction: A systematic review of different methods used

Canine retraction is a very important step in treatment of patients with crowding, or first premolar extraction cases. In severe crowding cases until, the canines have been distilized to relive the crowding, space to correctly align the incisors will not be available. Correct positioning of the canines after retraction is of great importance for the function, stability, and esthetics. The aim of this systematic review was to examine, in an evidence-based way, which kinds of canine retraction methods/techniques are most effective and which have the least side effects. A literature survey was performed by applying the Medline Database (Entrez PubMed) and Science Direct database covering the period from 1985 to 2014, to find out efficient ways to accomplish canine retraction. Randomized controlled trials (RCTs), prospective and retrospective controlled studies, and clinical trials were included. Two reviewers selected and extracted the data independently and assessed the quality of the retrieved studies. The search strategy resulted in 324 articles, of which 22 met the inclusion criteria. Due to the vast heterogeneity in study methods, the scientific evidence was too weak to evaluate retraction efficiency during space closure. The data so far reviewed proved that elastomeric power chains, elastic threads, magnets, NiTi coil springs, corticotomies, distraction osteogenesis, and laser therapy, all are able to provide optimum rate of tooth movements. All the methods were nearly similar to each other for retraction of canines Most of the techniques lead to anchorage loss in various amounts depending on the methods used. Most of the studies had serious problems with small sample size, confounding factors, lack of method error analysis, and no blinding in measurements. To obtain reliable scientific evidence, controlled RCT's with sufficient sample sizes are needed to determine which method/technique is the most effective in the respective retraction situation. Further studies should also consider patient acceptance and cost analysis as well as implants and minor surgeries for canine retraction.

Evaluation of canine retraction following periodontal distraction using NiTi coil spring and implants - A clinical study

OBJECTIVE

To evaluate the amount of canine retraction with periodontal distraction using miniscrew implants and NiTi coil spring.

MATERIAL AND METHOD

Sample comprised of 25 patients who were scheduled for all 1st premolar extraction (13 males and 12 females), in the age range of 16-22 years with mean age 18.8 ± 2.7 years. For each patient left side served as control side (Group I) and right side as experimental side (Group II). At the time of first premolar extraction, periodontal distraction was performed only on the experimental side, followed by retraction of canine from mini-implant by closed NiTi coil spring on both the sides. "Nemotech" software was used to evaluate the amount of canine retraction for a period of 3 months.

RESULTS

Significantly higher amount of tooth movement was seen from T0-T1 and from T1-T2 in Group II for the maxillary parameters 3C-5C, 6CF-3C, 3C-I/3C-J and for the mandibular parameter 6CF″-3C″. Whereas no significant amount of tooth movement was observed for maxillary and mandibular parameters between T2-T3 except for 6CF″-3C″ (p ≤ 0.01) which was significantly higher for the Group II.

CONCLUSION

There was accelerated canine retraction on the periodontal distraction side as compared to the control side, with negligible anchorage loss.

En masse retraction versus two-step retraction of anterior teeth in extraction treatment of bimaxillary protrusion

In the present report, two techniques of space closure; two-step anterior teeth retraction (TSR) and en masse retraction (ER) were used in two adult patients who had bimaxillary protrusion and were treated with four premolar extractions and fixed orthodontic appliance therapy. Both patients had a Class I dental malocclusion and the same chief complaint, which is protrusive lips. Anterior teeth were retracted by two-step retraction; canine sliding followed by retraction of incisors with T-loop archwire in the first patient and by en masse retraction using Beta titanium alloy T-loop archwire in the second case. At the end of treatment, good balance and harmony of lips was achieved with maintenance of Class I relationships. The outcome of treatment was similar in the two patients with similar anchorage control. ER can be an acceptable alternative to the TSR during space closure since it is esthetically more acceptable. However, it requires accurate bending and positioning of the T-loop.

TADs: an evolutionary road to success

This is a literature search about the clinical use of temporary anchorage devices (TADs) as a means of providing effective orthodontic anchorage. It takes the reader through a journey from the initial description of the technique to the enormous popularity TADs are currently experiencing in clinical practice. This paper aims to present good quality clinical information to allow the clinician and the patient to make an informed decision.

CLINICAL RELEVANCE

The purpose of this literature review is to provide readers with an overview of the current available literature on this subject and encourage general dental practitioners to adopt a more evidence-based approach to this aspect of orthodontic care.

Comparisons of the chondroitin sulphate levels in orthodontically moved canines and the clinical outcomes between two different force magnitudes

The aims of this study were to compare the chondroitin sulphate (CS) levels in gingival crevicular fluid (GCF) of moved canines using either 70 or 120 g of orthodontic force, and to compare the rate of tooth movement and the amount of pain between these two force magnitudes. Sixteen patients (6 males and 10 females; aged 16.91 ± 2.99 years), with class I malocclusion, who required orthodontic treatment with first premolar extractions, were recruited. The force magnitudes used to move the maxillary canines distally were controlled at 70 and 120 g on the right and the left sides, respectively. GCF samples were collected with Periopaper(®) strips before and during orthodontic tooth movement. Competitive ELISA with monoclonal antibody was used to measure the CS levels. The distance of tooth movement and the amount of pain assessed by visual analog scale (VAS) scores were evaluated. The medians of CS levels during the loaded period were significantly greater than those during the unloaded period (P < 0.05). The differences between the medians of CS levels of 70 g and 120 g retraction force during each 1 week period were not significant. There was no significant difference in the rates of canine movement between these two force magnitudes. However, using 120 g, the medians of VAS scores were significantly greater than those with 70 g (P < 0.05). Collectively, 70 g retraction force appears to be sufficient and more suitable than 120 g force as it causes no difference in biochemically-assessed bone remodelling activity, the same rate of tooth movement, reduced pain and better comfort.

Mini-implant and Nance button for initial retraction of maxillary canines: a prospective study in cast models

OBJECTIVE: Bone anchorage is a key factor for the successful management of some malocclusions for it allows the application of continuous forces, decreases treatment time and is independent from patient compliance. METHODS: The goal of this work was to establish a dental model comparison in order to measure the anchorage loss after the initial retraction of upper canines between the two groups. Group A used mini-implants and Group B used Nance button. All patients had two models cast (M1 and M2). The first models were taken on baseline (M1) and the other models were taken after canine retraction (M2). RESULTS: All measurements were pooled and submitted to statistical analysis. In order to verify the inter-examiner systematic error a paired t-test was performed. Dahlberg's formula was used to estimate the casual error. For comparison purposes between Before and After stages, a paired t-test was done. For the comparison between mini-implant and Nance button groups, a Student t-test was applied. All tests adopted a 5% (p<0.05) significance level. CONCLUSION: No statistically significant difference was observed between the two groups when measurements and comparisons to assess molar anchorage loss after canine initial retraction were performed. Two different anchorage systems were applied on dental models (mini-implants and Nance's button) for each group.

Is traditional treatment a good option for an adult with a Class II deepbite malocclusion?

The Tweed-Merrifield directional force technique is a useful treatment approach for a patient with a Class II malocclusion with dentoalveolar protrusion. The purpose of this case report was to present the diagnosis and treatment descriptions of a patient with an Angle Class II malocclusion complicated by tooth losses, severe dentoalveolar protrusion, and skeletal discrepancy. Treatment involved extraction of the maxillary first premolars, high-pull headgear to enhance anchorage, and high-pull J-hook headgear to retract and intrude the maxillary anterior segments. A successful outcome was achieved with traditional orthodontic treatment in this borderline surgical case.

The clinical and laboratory effects of bracket type during canine distalization with sliding mechanics

OBJECTIVE

To compare the extent of canine movement with sliding mechanics between a self-ligating (SC) bracket and a modified twin design (MT) bracket. To test the in vitro coefficient of friction (COFs) of these two metal brackets on 0.019- × 0.025-inch, stainless-steel arch wires.

MATERIALS AND METHODS

For the clinical portion of this study, a split-mouth design was used to bond the brackets of 19 patients. Canine distalization was achieved on a 0.019- × 0.025-inch, stainless-steel arch wire with a nickel-titanium, closed-coil spring strained between a mini-screw and a canine bracket. The linear and angular measurements were performed using lateral cephalometric radiographs taken before and after canine distalization. A tribometer was also used to measure the COFs of the bracket types in vitro. For comparisons, Student's t-tests for paired and unpaired samples were used at the 95% confidence level.

RESULTS

The extent of canine movement and the changes in the canine and molar teeth angles were not significantly different between the SC and MT brackets. After 8 weeks, the mean canine movements were 1.83 and 1.89 mm in the maxilla and 1.79 mm and 1.70 mm in the mandible with the SC and MT brackets, respectively. The mean COF of the MT brackets (0.21) was significantly lower than that of the SC brackets (0.37) during in vitro testing.

CONCLUSION

It is suggested that the rate of canine distalization was not different between the two groups, although in vitro COFs of the SC bracket was higher.

A comparison of space closure rates between preactivated nickel-titanium and titanium-molybdenum alloy T-loops: a randomized controlled clinical trial

The purpose of this study was to conduct a prospective randomized controlled clinical trial to evaluate the rate of space closure and tooth angulation during maxillary canine retraction using preactivated T-loops made from titanium-molybdenum alloy (TMA) and nickel-titanium (NiTi). Twelve patients (six males and six females) aged between 13 and 20 years who had upper premolar extractions were included, and each acted as their own control, with a NiTi T-loop allocated to one quadrant and TMA to the other using a split mouth block randomization design. The loops were activated 3 mm at each visit to deliver a load of approximately 150 g to the upper canine teeth. Maxillary dental casts, taken at the first and each subsequent monthly visit, were used to evaluate changes in extraction space and canine angulation. All used T-loops were compared with unused loops in order to assess distortion. Mixed model statistical analysis was used to adjust for confounding variables. The mean rate of canine retraction using preactivated NiTi and TMA T-loops was 0.91 mm/month (±0.46) and 0.87 mm/month (±0.34), respectively. The canine tipping rates were 0.71 degrees/month (±2.34) for NiTi and 1.15 degrees/month (±2.86) for TMA. Both the rate of space closure and the tipping were not significantly different between the two wire types. The average percentage distortion of the TMA T-loop was 10 times greater than that of the NiTi loops when all other variables were matched. There was no difference in the rate of space closure or tooth angulation between preactivated TMA or NiTi T-loops when used to retract upper canines. The NiTi loops possessed a greater ability to retain and return to their original shapes following cyclical activation.

Maxillary canine retraction with self-ligating and conventional brackets

OBJECTIVE

To measure space closure during the retraction of upper permanent canines with self-ligating and conventional brackets.

MATERIALS AND METHODS

Fifteen patients who required maxillary canine retraction into first premolar extraction sites as part of their orthodontic treatment completed this study. In a random split-mouth design, the retraction of upper canines was performed using an elastomeric chain with 150 g of force. The evaluations were performed in dental casts (T0, initial; T1, 4 weeks; T2, 8 weeks; T3, 12 weeks). The amount of movement and the rotation of the canines as well as anchorage loss of the upper first molars were evaluated.

RESULTS

There was no difference between self-ligating and conventional brackets regarding the distal movement of upper canines and mesial movement of first molars (P > .05). Rotation of the upper canines was minimized with self-ligating brackets (P < .05).

CONCLUSION

Distal movement of the upper canines and anchorage loss of the first molars were similar with both conventional and self-ligating brackets. Rotation of the upper canines during sliding mechanics was minimized with self-ligating brackets.