Midpalatal implants vs headgear for orthodontic anchorage—a randomized clinical trial: Cephalometric results

Orthodontic maximum anchorages in malocclusion treatment: A systematic review and network meta-analysis

OBJECTIVE

We did a network meta-analysis and systematic review among patients seeking for maximum anchorage and provided a guidance of selecting certain systems in clinical practice.

METHODS

Seven databases were searched, and randomized controlled trials (RCTs) published with no language restrictions from January 1994 to February 2021 comparing any of the following seven anchorage systems for maximum anchorage orthodontic treatment were selected(PROSPERO: CRD42019117995). A network meta-analysis (NMA) was then conducted to integrate direct evidence with indirect evidence based on logical inference to compare and rank treatments for maximum anchorages in the capacity of maintaining anchorage and duration of total treatment time.

RESULTS

Nine publications with 522 participants were considered eligible and were taken into evaluation. According to the capacity of anchorage reinforcement, three skeleton anchorages including miniscrew implants, midpalate implants and Onplant midpalate implants were significantly more effective than conventional anchorages including headgears, TPAs and Nance buttons respectively. According to conventional anchorages, headgears and Nance buttons were significantly more effective than TPA. The strategy ranking reflected the same results as above. However, miniscrew implants required the longest total treatment time.

CONCLUSIONS

In general, miniscrew impants are most effective in reserving anchorage. Nance buttons require the least total treatment time. Total evidence is graded as moderate. Midpalatal implants might be the best choice when doing treatment planning because it has the most favorable balance between effectiveness and treatment time. But data analysis of the acceptability and acquisition cost of those anchorage systems must be done to make final decisions.

Treatment effects of Carriere Motion Appliance on patients with class II malocclusion: A systematic review and meta-analysis

OBJECTIVE

To investigate the treatment effects of Carriere Motion Appliance (CMA) on class II patients.

METHODS

A comprehensive electronic search was performed in PubMed, Scopus, Web of science, ScienceDirect, ProQuest (dissertation and thesis), Google Scholar and ClinicalTrials.gov. All types of clinical trials that contained at least pre- and post-treatment measures of patients treated by CMA were included in this systematic review and meta-analysis. The risk of bias was assessed for all included studies. The considered outcomes were the skeletal, dento-alveolar, soft tissues, temporomandibular joint and airway changes, electromyographic activity and stability.

RESULTS

Sixteen studies were included in this systematic review and meta-analysis. The absence of randomized controlled trials which could induce confounding and selection of participant bias is considered the main risk of bias affecting the available studies. Regarding the skeletal changes, no significant effects were appreciated (changes in SNB angle; SMD=-0.13; 95% CI (-0.57, 0.31); P=0.58. Changes in SN-MP; SMD=-0.11; 95% CI (-0.54, 0.33); P=0.64). With respect to the dento-alveolar changes, an increased lower incisor's proclination (L1-MP) was observed; SMD=-0.69; 95% CI (-1.14, -0.24); P=0.003. CMA caused an increase in the airway volume, an increase in the masseter and temporalis muscles activities and a minor relapse of malocclusion after 4-years of follow-up. The results should be taken with caution because only secondary level of evidence was found.

CONCLUSIONS

The CMA used for the treatment of class II malocclusion did not cause skeletal changes; however, largely dento-alveolar effects were noticed. Prospective randomized clinical trials are highly recommended.

Palatal temporary skeletal anchorage devices (TSADs): What to know and how to do?

OBJECTIVES

Since palatal temporary skeletal anchorage devices (TSADs) have become important tools for orthodontic treatment, this narrative review was aimed to provide an updated and integrated guidelines for the clinical application of palatal TSADs.

SETTING AND SAMPLE POPULATION

A narrative review article including researches on palatal TSADs in orthodontics related to anatomy, success rate and clinical application.

MATERIALS AND METHODS

The anatomical characteristics, success rate and its consideration factors and clinical application of palatal TSADs based on the direction of tooth movement were evaluated.

RESULTS

To improve the stability of TSADs, hard tissue factors such as bone depth, cortical bone thickness, bone density and soft tissue thickness were evaluated. Anatomically risky structures, including the nasopalatine foramen, canal and the greater palatine foramen, nerve, vessel need to be identified before placement. The success rate of palatal TSADs was greater than that of the buccal inter-radicular space. Palatal TSADs have been used for various purposes because they can control tooth movement in all directions and, three-dimensionally; their applications include the retraction of anterior teeth, protraction of posterior teeth, distalization, intrusion, expansion and constriction. They can be applied directly or indirectly to the lingual arch or transpalatal arch. Design modifications using splinted 2 miniscrews have been suggested.

CONCLUSION

Palatal TSADs allow clinicians to perform minimally invasive and easy placement with good stability by understanding the anatomical characteristics of the palatal region, and they show good control over 3-dimensional tooth movements in various clinical cases.

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.

Periodontal implications of surgical-orthodontic treatment of an impacted dilacerated maxillary incisor: A case report with a 2-year follow-up

The treatment of an 8-year-old girl with a dilacerated maxillary incisor began in the mixed dentition; a modified palatal arch attached to the molars served as anchorage for the forced eruption of the dilacerated tooth to prevent the intrusion of the adjacent teeth and reduce the risk of root resorption. Two surgical sessions were planned: the first to permit the closed eruption; the second was an apically positioned flap to add attached gingiva to the labial side of the erupting tooth. The result was an optimal periodontal outcome; moreover, the roots of the adjacent teeth did not show any sign of resorption at the end of the forced eruption. The tooth was vital at the end of the treatment, and the apex covered by alveolar mucosa. The root developed normally throughout the treatment, and the periodontium was healthy and esthetically acceptable at the 2-year follow-up. Further study is needed to assess the advantages of the combined surgical-orthodontic treatment.

Effectiveness of anchorage with temporary anchorage devices during anterior maxillary tooth retraction: A randomized clinical trial

Objective

This study evaluated the efficiency of anchorage provided by temporary anchorage devices (TADs) in maxillary bicuspid extraction cases during retraction of the anterior teeth using a fixed appliance.

Methods

Patients aged 12 to 50 years with malocclusion for which bilateral first or second maxillary bicuspid extractions were indicated were included in the study and randomly allocated to the TAD or control groups. Retraction of the anterior teeth was achieved using skeletal anchorage in the TAD group and conventional dental anchorage in the control group. A computed tomography (CT) scan was performed after alignment of teeth, and a second CT scan was performed at the end of extraction space closure in both groups. A three-dimensional superimposition was performed to visualize and quantify the maxillary first molar movement during the retraction phase, which was the primary outcome, and the stability of TAD movement, which served as the secondary outcome.

Results

Thirty-four patients (17 in each group) underwent the final analysis. The two groups showed a significant difference in the movement of the first maxillary molars, with less significant anchorage loss in the TAD group than that in the control group. In addition, TAD movement showed only a slight mesial movement on the labial side. On the palatal side, the mesial TAD movement was greater.

Conclusions

In comparison with conventional dental anchorage, TADs can be considered an efficient source of anchorage during retraction of maxillary anterior teeth. TADs remain stable when correctly placed in the bone during the anterior tooth retraction phase.

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.

Comparison of orthodontic tooth movement between adolescents and adults based on implant superimposition

OBJECTIVE

We compared tooth movement under maximum anchorage control with mini-screw implants in growing and non-growing patients.

METHODS

In total, 15 adolescent (G1) and 19 adult (G2) patients with prognathic profiles were selected. All patients underwent first premolar extraction treatment with mini-screw implants for maximum anchorage control. Cone-beam computed tomography (CBCT) data were obtained immediately after implant placement (T1) and at the end of anterior tooth retraction (T2). Tooth movement and root length changes of the maxillary first molar, canine, and incisors were evaluated with three-dimensional models constructed using CBCT data obtained before and after orthodontic retraction through the superimposition of stable implants.

RESULTS

Distal movement of the molar crown was observed in G2, but mesial movement was observed in G1. Mesial tipping of the first molar (1.82 ± 6.76°) was seen in G1 and distal tipping (4.44 ± 3.77°) was observed in G2. For the canines, mesial crown tipping (0.33 ± 4.99°) was noted in G1 and distal crown tipping (8.00 ± 5.57°) was observed in G2. In adults, the lingual inclinations of the lateral and central incisors were 11.91 ± 7.01° and 11.47 ± 6.70°, with 0.99 ± 1.22 mm and 1.08 ± 1.20 mm root retraction, respectively. In adolescents, the torque changes were smaller (lateral incisors, 8.25 ± 10.15°; central incisors, 9.82 ± 8.97°) and the root retractions were 0.31 ± 1.81 mm and 0.77 ± 1.59 mm, respectively. Less shortening of the central incisor roots occurred in adolescents than in adults.

CONCLUSIONS

Tooth movements, such as anchor molar angular change, the canine tipping pattern, and the amount of incisor retraction, differed between adolescents and adults treated using the same anchorage with mini-screw implants, bracket prescription, and en masse retraction method. Anchorage strength of the first molars, canine movement patterns, and incisor retraction ranges are not determined by the anchorage device alone; growth and alveolar limitations also play roles.

Evaluation of Palatal Bone Thickness for Insertion of Orthodontic Mini-Implants in Adults and Adolescents

OBJECTIVE

The aim of this study was to measure palatal bone thickness and select relatively safe regions for mini-implant insertion, and to determine the effect of age and sex on palatal bone thickness and whether there is any difference between right and left sides.

MATERIALS AND METHODS

Cone beam computed tomographic (CBCT) evaluation was used on 107 healthy orthodontic patients, including 51 adolescents (12.90 ± 1.71 years) and 56 adults (26.09 ± 4.35 years), who were selected from the Zhongshan Hospital, Fudan University (Shanghai, China). Seventy-two sites of bone thickness were measured in the palate. Intragroup, intergroup, and sex differences were analyzed by repeated measures analysis of variance.

RESULTS

Palatal bone thickness exhibited significant differences in 3 anteroposterior areas of the 2 groups. From anterior to posterior region, palatal bone thickness gradually decreased. Meanwhile, on the sagittal plane, palatal bone thickness decreased gradually from reference line 0 to 9 mm among adults, and from reference line 0 to 12 mm among adolescents posterior to the level of the posterior rim of the incisive foramen. However, on the coronal plane, no significant differences were found in the palatal bone thickness among reference lines 2, 4, 6, and 8 mm lateral to the midpalatal suture. Nor were there differences between right and left sides, between adults and adolescents or between males and females.

CONCLUSIONS

In terms of bone thickness, the anterior region is relatively safe for orthodontic mini-implant insertion. However, since subjects vary greatly, CBCT scans are needed before undertaking mini-implant insertion.

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.

Effectiveness of orthodontic miniscrew implants in anchorage reinforcement during en-masse retraction: A systematic review and meta-analysis

INTRODUCTION

The aim of this systematic review was to compare the effectiveness of orthodontic miniscrew implants-temporary intraoral skeletal anchorage devices (TISADs)-in anchorage reinforcement during en-masse retraction in relation to conventional methods of anchorage.

METHODS

A search of PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science was performed. The keywords were orthodontic, mini-implants, miniscrews, miniplates, and temporary anchorage device. Relevant articles were assessed for quality according to Cochrane guidelines and the data extracted for statistical analysis. A meta-analysis of raw mean differences concerning anchorage loss, tipping of molars, retraction of incisors, tipping of incisors, and treatment duration was carried out.

RESULTS

Initially, we retrieved 10,038 articles. The selection process finally resulted in 14 articles including 616 patients (451 female, 165 male) for detailed analysis. Quality of the included studies was assessed as moderate. Meta-analysis showed that use of TISADs facilitates better anchorage reinforcement compared with conventional methods. On average, TISADs enabled 1.86 mm more anchorage preservation than did conventional methods (P <0.001).

CONCLUSIONS

The results of the meta-analysis showed that TISADs are more effective than conventional methods of anchorage reinforcement. The average difference of 2 mm seems not only statistically but also clinically significant. However, the results should be interpreted with caution because of the moderate quality of the included studies. More high-quality studies on this issue are necessary to enable drawing more reliable conclusions.

Comparison of temporary anchorage devices and transpalatal arch-mediated anchorage reinforcement during canine retraction

Objective:

The purpose of this study was to compare the dental and skeletal effects of canine retraction using conventional anchorage reinforcement systems and comparing them with the usage of TADs.

Materials and Methods:

The sample consisted of 50 patients having Class I malocclusions with bimaxillary protrusion indicated for first premolar extraction, and allocated into two groups. The first group consisted of 25 patients with a mean age of 18,7 years (min:14, max:22 years, 16 girls and 9 boys) that TADs were applied as an anchorage mechanic between attached gingiva of upper second premolar and first molar teeth. The second group consisted of 25 patients with a mean age of 19,4 years (min:15, max:23 years, 14 girls and 11 boys) that conventional molar anchorage with Transpalatal arch (TPA) was applied for the anchorage mechanics against canine retraction.

Results:

The results showed that mean mesial movement and the tipping of the first molars in TAD group between T0 - T1 were insignificant (P > 0,05), however in the TPA group were significant (P<0,01). Vertical movement of the molars were not significant when two groups were compared (P>0,05).

Conclusion:

Although TPA is a useful appliance, it doesn't provide an effective anchorage control on anteroposterior movement maxillary first molar teeth concerning first premolar extraction treatment. TADs are more convenient to provide absolute anchorage during maxillary canine retraction in contrast to transpalatal arch.

Implants for orthodontic anchorage: success rates and reasons of failures

INTRODUCTION

The aims of this study were to analyze the success rate of mini-implants and miniscrews and to report the reasons behind them.

MATERIALS AND METHODS

An electronic literature search from PubMed databases and a hand search in implant- and orthodontic-related journals were performed until December 31, 2011. Human clinical studies in English that reported temporary anchorage devices used for orthodontic purpose with at least 6 months follow-up were included. In addition, the minimal number of implants had to be at least 10. Implants placed in maxilla, mandible, and hard palate were included.

RESULTS

The initial search resulted in 847 articles, of which 46 were further evaluated. Finally, 29 studies were qualified and classified into 2 groups: implants placed in maxilla and mandible (group 1) and implants placed in hard palate (group 2). A meta-analysis performed for groups 1 and 2 showed 87.8% and 93.8% survival rate, respectively. In addition, the most common cause for implants failure was surgery-related factors.

CONCLUSION

Mini-implant survival rate is location dependent, with those placed in the palate showing higher success rates. In addition, failures most commonly occur because of surgery-related factors.

Reinforcement of anchorage during orthodontic brace treatment with implants or other surgical methods

BACKGROUND

The term anchorage in orthodontic treatment refers to methods of controlling unwanted tooth movement. This is provided either by anchor sites within the mouth, such as the teeth and the palate, or from outside the mouth (headgear). Recently, new methods of providing anchorage have been developed using orthodontic implants which are surgically inserted into the bone in the mouth. This is termed surgical anchorage. This is an update of a Cochrane review first published in 2007.

OBJECTIVES

To assess the effects of surgical anchorage techniques compared to conventional anchorage in the prevention of unwanted tooth movement in patients undergoing orthodontic treatment by evaluating the mesiodistal movement of upper first molar teeth. A secondary objective was to compare the effects of one type of surgical anchorage with another.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 28 October 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 9), MEDLINE via OVID (1946 to 28 October 2013) and EMBASE via OVID (1980 to 28 October 2013). We handsearched key international orthodontic and dental journals, and searched the trial database ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing and unpublished studies.

SELECTION CRITERIA

Randomised controlled trials comparing surgical anchorage with conventional anchorage in orthodontic patients. Trials comparing two types of surgical anchorage were also included.

DATA COLLECTION AND ANALYSIS

At least two review authors independently and in duplicate extracted data and carried out risk of bias assessments. We contacted study authors to clarify aspects of study design and conduct, and to obtain unreported data.

MAIN RESULTS

Fourteen new studies were added in this update resulting in a total of 15 studies reporting data from 561 randomised patients. The studies were conducted in Europe, India, China, South Korea and the USA. The age range of patients was commonly restricted to adolescents or young adults, however the participants of two studies were from a much wider age range (12 to 54 years). The distribution of males and females was similar in eight of the studies, with a predominance of female patients in seven studies.Eight studies were assessed to be at high overall risk of bias; six studies at unclear risk of bias; one study at low risk of bias.Ten studies with 407 randomised and 390 analysed patients compared surgical anchorage with conventional anchorage for the primary outcome of mesiodistal movement of upper first molars. We carried out a random-effects model meta-analysis for the seven studies that fully reported this outcome. There was strong evidence of an effect of surgical anchorage on this outcome. Compared with conventional anchorage, surgical anchorage was more effective in the reinforcement of anchorage by 1.68 mm (95% confidence interval (CI) -2.27 mm to -1.09 mm; seven studies, 308 participants analysed) with moderate quality of evidence (one study at high overall risk of bias, five studies at unclear risk of bias, one study at low risk of bias). This result should be interpreted with some caution, however, as there was a substantial degree of heterogeneity for this comparison. There was no evidence of a difference in overall duration of treatment between surgical and conventional anchorage (-0.15 years; 95% CI -0.37 years to 0.07 years; three studies, 111 analysed patients) with low quality of evidence (one study at high overall risk of bias and two studies at unclear risk of bias). Information on patient-reported outcomes such as pain and acceptability was limited and inconclusive.When direct comparisons were made between two types of surgical anchorage, there was a lack of evidence to suggest that any one technique was better than another.No included studies reported adverse effects.

AUTHORS' CONCLUSIONS

There is moderate quality evidence that reinforcement of anchorage is more effective with surgical anchorage than conventional anchorage, and that results from mini-screw implants are particularly promising. While surgical anchorage is not associated with the inherent risks and compliance issues related to extraoral headgear, none of the included studies reported on harms of surgical or conventional anchorage.

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.

Evaluation of palatal bone density in adults and adolescents for application of skeletal anchorage devices

OBJECTIVES

To measure the cortical and cancellous bone densities of the palatal area in adolescents and adults and to compare bone quality among placement sites of temporary anchorage devices.

MATERIALS AND METHODS

One hundred twenty cone beam computerized tomography scans were obtained from 60 adolescents (mean age, 12.2 ± 1.9 years) and 60 adults (24.7 ± 4.9 years). The measurements of palatal bone density were made in Hounsfield units (HU) at 72 sites at the intersections of eight mediolateral and nine anterioposterior reference lines using InVivoDental software. Repeated-measures analysis of variance was used to analyze intragroup and intergroup differences.

RESULTS

The cortical and cancellous bone densities in the adults (816 and 154 HU, respectively) were significantly higher than those in the adolescents (606 and 135 HU; P < .001 and P  =  .032, respectively). However, the anterior portion of the cortical bone in adolescents had similar density values to the posterior portion of the cortical bone in adults. Gender comparison revealed that females had greater cortical bone densities (769 HU) than their male counterparts did (654 HU; P < .001).

CONCLUSIONS

Palatal bone densities were significantly higher in adults than in adolescents, and the anterior palatal areas of adolescents were of similar values to those at the posterior palate of adults.

Comparison of anchorage capacity between implant and headgear during anterior segment retraction

OBJECTIVE

To compare the anchorage effects of the implants and the headgear for patients with anterior teeth retraction in terms of incisor retraction, anchorage loss, inclination of maxillary incisors, positional change of maxillary basal bone, and treatment duration.

MATERIALS AND METHODS

An electronic search for relative randomized controlled trials (RCTs) prospective and retrospective controlled trials was done through the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Medline, and CNKI, regardless of language of study. Study selection, methodological quality assessment, and data extraction were performed by two reviewers independently. Meta-analysis was performed when possible; otherwise descriptive assessment was done.

RESULTS

The search yielded 35 articles, of which eight met the inclusion criteria and were categorized into five groups according to types of intervention. For the midpalatal implant, the anchorage loss was much less than for the headgear group, with insignificant differences in terms of anterior teeth retraction, maxillary incisor inclination, positional change of basal bone, and treatment duration. For the mini-implant, greater anterior teeth retraction and less anchorage loss were demonstrated, with inconsistent results for the other measures. For the onplant, less anchorage loss was noted, with insignificant differences for the other measures.

CONCLUSIONS

The skeletal anchorage of the midpalatal implant, mini-implant, and onplant offer better alternatives to headgear, with less anchorage loss and more anterior teeth retraction. There were inconsistent results from the included studies in terms of maxillary incisor inclination, positional change of maxillary basal bone, and treatment duration. More qualified RCTs are required to provide clear recommendations.

Asymmetric headgear for differential molar movement: a study using finite element analysis

OBJECTIVE

To compare the effects of four different asymmetric headgear systems.

DESIGN

A mathematical method for three-dimensional data called finite element analysis.

SETTING

The Orthodontic Department, the Federal University of Rio de Janeiro and the Metallurgical Engineering Department of the Fluminense Federal University.

METHODS

Four systems of delivering an asymmetrical force to headgear were studied: using face-bow arms of different lengths, a symmetric face-bow with one of the arms bent outward in relation to the internal arch, a symmetric face-bow used in combination with a transpalatal arch activated to produce an asymmetric force, and a symmetric face-bow with the outer bow soldered to the inner bow on the side where a larger force will be applied.

RESULTS

All four systems were effective in promoting asymmetric distal movement of the molars. However, the symmetrical face-bow with the outer bow soldered to the inner bow (system 4) could be used in asymmetric mechanics if the bows are soldered on the opposite side to the proposed distalization. Lateral and occlusal displacing forces were observed in all systems as well as tip-back and rotational movements.

CONCLUSION

The simulated computer model used in this investigation suggests that a face-bow with a symmetrically soldered joint and arms of equal lengths used in combination with a transpalatal arch is the best headgear option when asymmetric movement of upper molars is desired.

Measuring 3-dimensional tooth movement with a 3-dimensional surface laser scanner

INTRODUCTION

Our aims in this study were to (1) develop a method of measuring 3-dimensional (3D) tooth movement using a 3D surface laser scanner, (2) test the accuracy of this method, and (3) compare the measurements with those from cephalometric radiographs.

METHODS

A method of superimposing pretreatment and posttreatment models on the palatal rugae was developed, and an experimental model was prepared to evaluate the accuracy and reliability of the laser scanner. Records were obtained from a prospective longitudinal randomized clinical trial evaluating anchorage loss with headgears and midpalatal osseointegrated implants as a source of anchorage in Chesterfield, United Kingdom. The pretreatment and posttreatment study models were analyzed by using a 3D laser scanner to measure the 3D tooth movement.

RESULTS

The laser scanner was accurate to 0.0235 mm for anteroposterior measurements and 0.0071 mm for buccolingual movements for every 0.5 mm of movement. The study model analysis showed that mesial molar movements were 1.38 mm on the right side and 1.11 mm on the left side for the implant group, and 2.24 mm on right side and 1.63 mm on left side for the headgear group, with no statistically significant difference between the groups. The results for vertical movement of molars showed extrusion on both sides in both groups but no statistically significant difference between the groups. In the transverse plane, the results were not statistically significantly different between the groups. The results from superimposition of lateral cephalograms were similar to those obtained from the scanner.

CONCLUSIONS

The 3D laser scanner provides accurate and reliable measurements of tooth displacement and can be considered an alternative to cephalometric radiographs.