Comparison of Skeletal and Conventional Anchorage Methods in Conjunction with Pre-operative Decompensation of a Skeletal Class III Malocclusion

Transfer accuracy of 3D printed versus CAD/CAM milled surgical guides for temporary orthodontic implants: A preclinical micro CT study

OBJECTIVES

Temporary anchorage devices (TADs) have become an integral part of comprehensive orthodontic treatments. This study evaluated the transfer accuracy of three-dimensional (3D) printed and computer-aided design/computer-aided manufacturing (CAD/CAM) milled surgical guides for orthodontic TADs using micro-computed tomography (CT) imaging in a preclinical trial.

METHODS

Overall, 30 surgical guides were used to place TADs into typodonts; 3D printing and CAD/CAM milling were used to produce the guides. The virtual target positions of the TADs were compared to the real positions in terms of spatial and angular deviations using digital superimposition. Micro-CT imaging was used to detect the positions. To evaluate reliability, two investigators collected the measurements twice. Intra-rater and inter-rater correlations were tested.

RESULTS

In total, 60 palatal TADs were evaluated. The mean coronal deviations in the print group ranged from 0.15 ± 0.20 mm to 0.71 ± 0.22 mm, whereas in the mill group, they ranged from 0.09 ± 0.15 mm to 0.83 ± 0.23 mm. At the apical tip, the overall deviations in the print group ranged from 0.14 ± 0.56 mm to 1.27 ± 0.66 mm, whereas in the mill group, they ranged from 0.15 ± 0.57 mm to 1.09 ± 0.44 mm. The mean intra-class and inter-class correlation coefficients ranged from 0.904 to 0.987. No statistically significant differences were found between the groups.

CONCLUSIONS

CAD/CAM milled guides yielded spatial and angular accuracies comparable to those of 3D printed guides with notable deviations in the vertical positioning of TADs.

CLINICAL SIGNIFICANCE

Digital planning of orthodontic temporary implants combines clinical predictability and the safety of surrounding tissue. Therefore, the transfer accuracy of the guides is crucial. This preclinical study was the first to evaluate CAD/CAM milling for orthodontic guides and found its accuracy comparable to that of the current "gold standard".

How Effective Are the Nance Appliance and Transpalatal Arch at Reinforcing Anchorage in Extraction Cases?

OBJECTIVE

This narrative review aimed to evaluate, based on current evidence, whether the transpalatal arch (TPA) and Nance appliance can effectively reinforce anchorage during fixed orthodontic treatment while also offering a comprehensive and in-depth overview of the existing literature on this subject.

MATERIALS AND METHODS

A thorough literature search was performed across multiple electronic databases to identify peer-reviewed articles relevant to the review.

RESULTS

Evidence suggests that the Nance appliance does not provide absolute anchorage. Additionally, patients experienced discomfort and inflammation of the palatal tissues. The transpalatal arch is also insufficient for maximum anteroposterior anchorage, and existing studies on its effectiveness in vertical anchorage control are inconsistent with conflicting data.

CONCLUSIONS

For patients with critical anchorage demand, mini-screws may be the method of choice, either solely or in combination with Nance or transpalatal arch, though they carry a risk of failure.

Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children

BACKGROUND

Prominent lower front teeth (Class III malocclusion) may be due to jaw or tooth position or both. The upper jaw (maxilla) can be too far back or the lower jaw (mandible) too far forward; the upper front teeth (incisors) may be tipped back or the lower front teeth tipped forwards. Orthodontic treatment uses different types of braces (appliances) fitted inside or outside the mouth (or both) and fixed to the teeth. A facemask is the most commonly reported non-surgical intervention used to correct Class III malocclusion. The facemask rests on the forehead and chin, and is connected to the upper teeth via an expansion appliance (known as 'rapid maxillary expansion' (RME)). Using elastic bands placed by the wearer, a force is applied to the top teeth and jaw to pull them forwards and downward. Some orthodontic interventions involve a surgical component; these go through the gum into the bone (e.g. miniplates). In severe cases, or if orthodontic treatment is unsuccessful, people may need jaw (orthognathic) surgery as adults. This review updates one published in 2013.

OBJECTIVES

To assess the effects of orthodontic treatment for prominent lower front teeth in children and adolescents.

SEARCH METHODS

An information specialist searched four bibliographic databases and two trial registries up to 16 January 2023. Review authors screened reference lists.

SELECTION CRITERIA

We looked for randomised controlled trials (RCTs) involving children and adolescents (16 years of age or under) randomised to receive orthodontic treatment to correct prominent lower front teeth (Class III malocclusion), or no (or delayed) treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our primary outcome was overjet (i.e. prominence of the lower front teeth); our secondary outcomes included ANB (A point, nasion, B point) angle (which measures the relative position of the maxilla to the mandible).

MAIN RESULTS

We identified 29 RCTs that randomised 1169 children (1102 analysed). The children were five to 13 years old at the start of treatment. Most studies measured outcomes directly after treatment; only one study provided long-term follow-up. All studies were at high risk of bias as participant and personnel blinding was not possible. Non-surgical orthodontic treatment versus untreated control We found moderate-certainty evidence that non-surgical orthodontic treatments provided a substantial improvement in overjet (mean difference (MD) 5.03 mm, 95% confidence interval (CI) 3.81 to 6.25; 4 studies, 184 participants) and ANB (MD 3.05°, 95% CI 2.40 to 3.71; 8 studies, 345 participants), compared to an untreated control group, when measured immediately after treatment. There was high heterogeneity in the analyses, but the effects were consistently in favour of the orthodontic treatment groups rather than the untreated control groups (studies tested facemask (with or without RME), chin cup, orthodontic removable traction appliance, tandem traction bow appliance, reverse Twin Block with lip pads and RME, Reverse Forsus and mandibular headgear). Longer-term outcomes were measured in only one study, which evaluated facemask. It presented low-certainty evidence that improvements in overjet and ANB were smaller at 3-year follow-up than just after treatment (overjet MD 2.5 mm, 95% CI 1.21 to 3.79; ANB MD 1.4°, 95% CI 0.43 to 2.37; 63 participants), and were not found at 6-year follow-up (overjet MD 1.30 mm, 95% CI -0.16 to 2.76; ANB MD 0.7°, 95% CI -0.74 to 2.14; 65 participants). In the same study, at the 6-year follow-up, clinicians made an assessment of whether surgical correction of participants' jaw position was likely to be needed in the future. A perceived need for surgical correction was observed more often in participants who had not received facemask treatment (odds ratio (OR) 3.34, 95% CI 1.21 to 9.24; 65 participants; low-certainty evidence). Surgical orthodontic treatment versus untreated control One study of 30 participants evaluated surgical miniplates, with facemask or Class III elastics, against no treatment, and found a substantial improvement in overjet (MD 7.96 mm, 95% CI 6.99 to 8.40) and ANB (MD 5.20°, 95% CI 4.48 to 5.92; 30 participants). However, the evidence was of low certainty, and there was no follow-up beyond the end of treatment. Facemask versus another non-surgical orthodontic treatment Eight studies compared facemask or modified facemask (with or without RME) to another non-surgical orthodontic treatment. Meta-analysis did not suggest that other treatments were superior; however, there was high heterogeneity, with mixed, uncertain findings (very low-certainty evidence). Facemask versus surgically-anchored appliance There may be no advantage of adding surgical anchorage to facemasks for ANB (MD -0.35, 95% CI -0.78 to 0.07; 4 studies, 143 participants; low-certainty evidence). The evidence for overjet was of very low certainty (MD -0.40 mm, 95% CI -1.30 to 0.50; 1 study, 43 participants). Facemask variations Adding RME to facemask treatment may have no additional benefit for ANB (MD -0.15°, 95% CI -0.94 to 0.64; 2 studies, 60 participants; low-certainty evidence). The evidence for overjet was of low certainty (MD 1.86 mm, 95% CI 0.39 to 3.33; 1 study, 31 participants). There may be no benefit in terms of effect on ANB of alternating rapid maxillary expansion and constriction compared to using expansion alone (MD -0.46°, 95% CI -1.03 to 0.10; 4 studies, 131 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

Moderate-certainty evidence showed that non-surgical orthodontic treatments (which included facemask, reverse Twin Block, orthodontic removable traction appliance, chin cup, tandem traction bow appliance and mandibular headgear) improved the bite and jaw relationship immediately post-treatment. Low-certainty evidence showed surgical orthodontic treatments were also effective. One study measured longer-term outcomes and found that the benefit from facemask was reduced three years after treatment, and appeared to be lost by six years. However, participants receiving facemask treatment were judged by clinicians to be less likely to need jaw surgery in adulthood. We have low confidence in these findings and more studies are required to reach reliable conclusions. Orthodontic treatment for Class III malocclusion can be invasive, expensive and time-consuming, so future trials should include measurement of adverse effects and patient satisfaction, and should last long enough to evaluate whether orthodontic treatment in childhood avoids the need for jaw surgery in adulthood.

Systematic review and network meta-analysis of the accuracy of the orthodontic mini-implants placed in the inter-radicular space by image-guided-based techniques

OBJECTIVE

The aim of the present systematic review and network meta-analysis (NMA) is to analyze the accuracy of image-guided-based orthodontic mini-implants placement techniques in the inter-radicular space.

METHODS

The study was conducted under the PRISMA recommendations. Three databases were searched up to July 2022. In vitro randomized experimental trials (RETs) including static computer-aided implant surgery (s-CAIS), mixed reality (MR), soft tissue static computer-aided implant surgery (ST s-CAIS) and conventional free-hand technique (FHT) for the orthodontic mini-implants placement in the inter-radicular space were selected. The risk of bias was assessed using the Current Research Information System scale. A random effects model was used in the NMA. Direct comparisons were combined with a random effects model in a frequentist NMA to estimate indirect comparisons, and the estimated effect size of the comparisons between techniques were analyzed by difference of means. Inconsistency was assessed with the Q test, with a significance level of p < 0.05, and a net heat plot.

RESULTS

A total of 92 articles was identified, and 8 RETs (8 direct comparisons of 4 techniques) were included in the NMA, which examined 4 orthodontic mini-implants placement techniques: s-CAIS, MR, ST s-CAIS, and FHT. Taking FHT as reference, s-CAIS and ST s-CAIS showed statistically significant coronal and apical deviation. In addition, s-CAIS showed statistically significant angular deviation. However, MR did not show statistically significant differences with respect to FHT, which presented the highest p-score. At the coronal deviation, ST s-CAIS presented the highest P-score (0.862), followed by s-CAIS (0.721). At the apical deviation, s-CAIS presented the highest P-score (0.844), followed by ST s-CAIS (0.791). Finally, at the angular deviation s-CAIS presented again the highest P-score (0.851).

CONCLUSIONS

Within the limitations of this study, it was found that the image-guided-based orthodontic mini-implants placement techniques showed more accuracy than the free-hand conventional placement technique; specially the computer-aided static navigation techniques for the orthodontic mini-implants placed in the inter-radicular space.

Application of the Digital Workflow in Orofacial Orthopedics and Orthodontics: Printed Appliances with Skeletal Anchorage

As digital workflows are gaining popularity, novel treatment options have also arisen in orthodontics. By using selective laser melting (SLM), highly customized 3D-printed appliances can be manufactured and combined with preformed components. When combined with temporary anchorage devices (TADs), the advantages of the two approaches can be merged, which might improve treatment efficacy, versatility, and patient comfort. This article summarizes state-of-the-art technologies and digital workflows to design and install 3D-printed skeletally anchored orthodontic appliances. The advantages and disadvantages of digital workflows are critically discussed, and examples for the clinical application of mini-implant and mini-plate borne appliances are demonstrated.

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.

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.

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.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children

BACKGROUND

Prominent lower front teeth (termed reverse bite; under bite; Class III malocclusion) may be due to a combination of the jaw or tooth positions or both. The upper jaw (maxilla) can be too far back or the lower jaw (mandible) too far forward, or both. Prominent lower front teeth can also occur if the upper front teeth (incisors) are tipped back or the lower front teeth are tipped forwards, or both. Various treatment approaches have been described to correct prominent lower front teeth in children and adolescents.

OBJECTIVES

To assess the effects of orthodontic treatment for prominent lower front teeth in children and adolescents.

SEARCH METHODS

We searched the following databases: Cochrane Oral Health Group's Trials Register (to 7 January 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 12), MEDLINE via OVID (1946 to 7 January 2013), and EMBASE via OVID (1980 to 7 January 2013).

SELECTION CRITERIA

Randomised controlled trials (RCTs) recruiting children or adolescents or both (aged 16 years or less) receiving any type of orthodontic treatment to correct prominent lower front teeth (Class III malocclusion). Orthodontic treatments were compared with control groups who received either no treatment, delayed treatment or a different active intervention.

DATA COLLECTION AND ANALYSIS

Screening of references, identification of included and excluded studies, data extraction and assessment of the risk of bias of the included studies was performed independently and in duplicate by two review authors. The mean differences with 95% confidence intervals were calculated for continuous data. Meta-analysis was only undertaken when studies of similar comparisons reported comparable outcome measures. A fixed-effect model was used. The I2 statistic was used as a measure of statistical heterogeneity.

MAIN RESULTS

Seven RCTs with a total of 339 participants were included in this review. One study was assessed as at low risk of bias, three studies were at high risk of bias, and in the remaining three studies risk of bias was unclear. Four studies reported on the use of a facemask, two on the chin cup, one on the tandem traction bow appliance, and one on mandibular headgear. One study reported on both the chin cup and mandibular headgear appliances.One study (n = 73, low quality evidence), comparing a facemask to no treatment, reported a mean difference (MD) in overjet of 4.10 mm (95% confidence interval (CI) 3.04 to 5.16; P value < 0.0001) favouring the facemask treatment. Two studies comparing facemasks to untreated control did not report the outcome of overjet. Three studies (n = 155, low quality evidence) reported ANB (an angular measurement relating the positions of the top and bottom jaws) differences immediately after treatment with a facemask when compared to an untreated control. The pooled data showed a statistically significant MD in ANB in favour of the facemask of 3.93 ° (95% CI 3.46 to 4.39; P value < 0.0001). There was significant heterogeneity between these studies (I2 = 82%). This is likely to have been caused by the different populations studied and the different ages at the time of treatment.One study (n = 73, low quality evidence) reported outcomes of the use of the facemask compared to an untreated control at three years follow-up. This study showed that improvements in overjet and ANB were still present three years post-treatment. In this study, adverse effects were reported but due to the low prevalence of temporomandibular (TMJ) signs and symptoms no analysis was undertaken.Two studies (n = 90, low quality evidence) compared the chin cup with an untreated control. Both studies found a statistically significant improvement in ANB, and one study also found an improvement in the Wits appraisal. Data from these two studies were not suitable for pooling.A single study of the tandem traction bow appliance compared to untreated control (n = 30, very low quality evidence) showed a statistically significant difference in both overjet and ANB favouring the intervention group.The remaining two studies did not report the primary outcome of this review.

AUTHORS' CONCLUSIONS

There is some evidence that the use of a facemask to correct prominent lower front teeth in children is effective when compared to no treatment on a short-term basis. However, in view of the general poor quality of the included studies, these results should be viewed with caution. Further randomised controlled trials with long follow-up are required.

Failure rates and associated risk factors of orthodontic miniscrew implants: a meta-analysis

INTRODUCTION

Risk factors concerning orthodontic miniscrew implants have not been adequately assessed. In this systematic review, we summarize the knowledge from published clinical trials regarding the failure rates of miniscrew implants used for orthodontic anchorage purposes and identify the factors that possibly affect them.

METHODS

Nineteen electronic databases and reference lists of included studies were searched up to February 2011, with no restrictions. Only randomized controlled trials, prospective controlled trials, and prospective cohort studies were included. Study selection and data extraction were performed twice. Failure event rates, relative risks, and the corresponding 95% confidence intervals were calculated. The random-effects model was used to assess each factor's impact. Subgroup and meta-regression analyses were also implemented.

RESULTS

Fifty-two studies were included for the overall miniscrew implant failure rate and 30 studies for the investigation of risk factors. From the 4987 miniscrew implants used in 2281 patients, the overall failure rate was 13.5% (95% confidence interval, 11.5-15.8). Failures of miniscrew implants were not associated with patient sex or age and miniscrew implant insertion side, whereas they were significantly associated with jaw of insertion. Certain trends were identified through exploratory analysis; however, because of the small number of original studies, no definite conclusions could be drawn.

CONCLUSIONS

Orthodontic miniscrew implants have a modest small mean failure rate, indicating their usefulness in clinical practice. Although many factors seem to affect their failure rates, the majority of them still need additional evidence to support any possible associations.

Clinical effectiveness of orthodontic miniscrew implants: a meta-analysis

The aim of this meta-analysis was to examine the clinical effectiveness of miniscrew implants (MI) used for anchorage reinforcement compared with that of conventional orthodontic means, as well as to assess the success rates of MIs and the possible risk factors affecting their clinical effectiveness. Literature searches were conducted, and, using specific inclusion and exclusion criteria, two independent investigators performed data extraction and analysis. Overall pooled estimates with 95% confidence intervals (CI) were obtained with the random-effects model. Eight out of 3183 original papers met the inclusion criteria. The mean difference of anchorage loss between the MI and conventional anchorage group was -2.4 mm (95% CI = -2.9 mm to -1.8 mm, p = 0). MIs significantly decreased or negated loss of anchorage. Anchorage loss seemed to be less in the mandible, when the MIs were inserted between the second premolar and the first molar, when 2 MIs were inserted per patient jaw, when they were directly connected, as well as when treatment lasted more than 12 months. MIs presented a success rate of 87.7%, with no significant differences between the various subgroups. However, the results of this meta-analysis should be interpreted with some caution because of the number, quality, and heterogeneity of the included studies.