Treatment effects of mini-implants for en-masse retraction of anterior teeth in bialveolar dental protrusion patients: A randomized controlled trial

Maxillary anterior en masse retraction using different antero-posterior position of mini screw: a 3D finite element study

Background

Nowadays, mini screws are used in orthodontic tooth movement to obtain maximum or absolute anchorage. They have gained popularity among orthodontists for en masse retraction of anterior teeth after first premolar extraction in maximum anchorage cases. The purpose of this study was to determine the type of anterior tooth movement during the time when force was applied from different mini screw placements to the anterior power arm with various heights.

Methods

A finite element method was used for modeling maxillary teeth and bone structure. Brackets, wire, and hooks were also designed for modeling. Two appropriate positions for mini screw in the mesial and distal of the second premolar were designed as fixed nodes. Forces were applied from the mini screw to four different levels of anterior hook height: 0, 3, 6, and 9 mm. Initial tooth movement in eight different conditions was analyzed and calculated with ANSYS software.

Results

Rotation of anterior dentition was decreased with a longer anterior power arm and the mesial placement of the mini screw. Bodily movements occurred with the 9-mm height of the power arm in both mini screw positions. Intrusion or extrusion of the anterior teeth segment depended on the level of the mini screw and the edge of the power arm on the Z axis.

Conclusions

According to the findings of this study, the best control in the sagittal plane during anterior en masse retraction was achieved by mesial placement of the mini screw and the 9-mm height of the anterior power arm. Where control in the vertical plane was concerned, distal placement of the mini screw with the 6-mm power arm height had minimum adverse effect on anterior dentition.

Comparison of the effects of mini-implant and traditional anchorage on patients with maxillary dentoalveolar protrusion

OBJECTIVE

To compare the treatment effects of mini-implants as anchor units with conventional methods of anchorage reinforcement in maxillary dentoalveolar protrusion patients in terms of skeletal, dental, and soft tissue changes.

MATERIALS AND METHODS

We searched the databases of the Cochrane Library, PubMed, OVIDSP, CBM, VIP, WanFang Data, and CNKI covering December 1966 to March 2016 for randomized controlled trials (RCTs) and clinical controlled trials that compared the treatment effects of mini-implants with conventional anchorage reinforcement in maxillary dentoalveolar protrusion patients. Literature filtering, data extraction, and methodological quality evaluation were finished independently by two researchers and disagreements were solved by discussion. Meta-analysis was performed when possible; otherwise descriptive assessment was done.

RESULTS

Through a predefined search strategy, we finally included 14 eligible studies. Eight outcomes were evaluated in this study: maxillary incisor retraction, maxillary molar movement, U1-SN, SNA, SN-MP, UL-E Plane, NLA and G-Sn-Pg.

CONCLUSIONS

Mini-implant anchorage was more effective in retracting the anterior teeth, produced less anchorage loss, and had a greater effect on SN-MP for the high-angle patients than did traditional anchorage. Both mini-implants and traditional anchorage underwent decreases in on U1-SN and SNA. More qualified RCTs are required to make reliable recommendations about the anchorage capacity of mini-implant and traditional anchorage in patients with maxillary dentoalveolar protrusion, especially on the UL-E plane, NLA, and G-Sn-Pg.

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.

Finite element analysis of maxillary incisor displacement during en-masse retraction according to orthodontic mini-implant position

Objective

Orthodontic mini-implants (OMI) generate various horizontal and vertical force vectors and moments according to their insertion positions. This study aimed to help select ideal biomechanics during maxillary incisor retraction by varying the length in the anterior retraction hook (ARH) and OMI position.

Methods

Two extraction models were constructed to analyze the three-dimentional finite element: a first premolar extraction model (Model 1, M1) and a residual 1-mm space post-extraction model (Model 2, M2). The OMI position was set at a height of 8 mm from the arch wire between the second maxillary premolar and the first molar (low OMI traction) or at a 12-mm height in the mesial second maxillary premolar (high OMI traction). Retraction force vectors of 200 g from the ARH (-1, +1, +3, and +6 mm) at low or high OMI traction were resolved into X-, Y-, and Z-axis components.

Results

In M1 (low and high OMI traction) and M2 (low OMI traction), the maxillary incisor tip was extruded, but the apex was intruded, and the occlusal plane was rotated clockwise. Significant intrusion and counter-clockwise rotation in the occlusal plane were observed under high OMI traction and -1 mm ARH in M2.

Conclusions

This study observed orthodontic tooth movement according to the OMI position and ARH height, and M2 under high OMI traction with short ARH showed retraction with maxillary incisor intrusion.

Differences of treatment outcomes between self-ligating brackets with microimplant and headgear anchorages in adults with bimaxillary protrusion

INTRODUCTION

Our aim was to determine differences between the outcomes of treatment using microimplant anchorage compared with headgear anchorage in adult patients with bimaxillary protrusion treated with self-ligating brackets.

METHODS

Thirty-one adult orthodontic patients (13 men, 18 women; age, 25.87 ± 3.37 years) who were diagnosed with bimaxillary protrusion were selected. All patients were treated with self-ligating brackets and maximum anchorage after extraction of 4 first premolars. Group 1 received microimplant anchorage, and group 2 received headgear. Lateral cephalometric radiographs were obtained before and after treatment. Differences in the skeletal and dental parameters between and within groups were analyzed.

RESULTS

No significant difference was observed in the mean treatment times between the groups (21.93 ± 3.10 vs 23.88 ± 2.68 months). There was no significant difference in skeletal measurements before or after treatment in patients who received microimplant anchorage. Patients who received headgear anchorage had an increase of the mandibular plane angle. The microimplant anchorage group had greater anterior tooth retraction and less maxillary molar mesialization than did the headgear group.

CONCLUSIONS

In both the anteroposterior and vertical directions, microimplant anchorage achieved better control than did the traditional headgear appliance during the treatment of bimaxillary protrusion.

Outcome assessment of lingual and labial appliances compared with cephalometric analysis, peer assessment rating, and objective grading system in Angle Class II extraction cases

OBJECTIVE

To validate our hypothesis that there would be significant differences in treatment outcomes, including cephalometric values, degree of root resorption, occlusal indices, and functional aspect, between cases treated with labial and lingual appliances.

MATERIALS AND METHODS

Twenty-four consecutively treated Class II cases with extractions and lingual appliance were compared with 25 matched cases treated with extraction and labial appliance. Orthodontic treatment outcomes were evaluated by cephalometric analysis, peer assessment rating, and an objective grading system (OGS). Additionally, functional analysis was also performed in both groups after orthodontic treatment. Statistical comparison was performed using the Wilcoxon signed rank test within the groups, and the Mann-Whitney U-test was used to compare between the labial and lingual groups.

RESULTS

The only significant difference between the groups was that the interincisal angle was larger in the lingual group than in the labial group. OGS evaluation showed that control over root angulation was significantly worse in the lingual group than in the labial group. There was no significant difference between groups in the amount of root resorption or in functional evaluation.

CONCLUSIONS

Generally, lingual appliances offer comparable treatment results to those obtained with labial appliances. However, care should be taken with lingual appliances because they are more prone to produce uprighted incisors and root angulation.

Biomechanical and histomorphometric properties of four different mini-implant surfaces

OBJECTIVES

To investigate the effects of surface roughness on the removal torque and bone-to-implant contact of four different orthodontic mini-implants.

MATERIALS AND METHODS

Mini-implants and circular discs were made from alloy Ti6Al4V grade 5. On the basis of surface treatment, the study was divided into four groups-group 1: machined (n = 32), no surface treatment; group 2: acid etched (n = 32), with hydrochloric acid; group 3 (n = 32), grit blasted with alumina; and group 4, grit blasted + acid etched (n = 32). Mean surface roughness (Ra) and quadratic average roughness (Rq) from each group were measured two dimensionally in non-contact mode by the optical profilometer. Contact angle measurement of discs from each group was done with a contact angle goniometer. Contact angle of liquids with different hydrophobicity and hydrophilicity was measured: 1. highly hydrophilic liquid sodium chloride (NaCl), 2. lightly hydrophobic liquid dimethylsulfoxide, 3. distilled water, and 4. human blood. One hundred and twenty-eight miniscrews, differing in surface treatment, were placed into the tibias and femurs of adult male New Zealand white rabbits. Rabbits were euthanized after 8 weeks and removal torque and bone-to-implant contact were measured.

RESULTS

Surface roughness of group 3 was significantly greater than other groups (P < 0.05). Group 4 had significantly lower contact angle measurements, both for blood and sodium chloride (NaCl; 40.26 degrees, 27.20 degrees) when compared to other three groups (P ≤ 0.01). Group 4 had significantly higher torque and bone-to-implant contact than group 3 (P = 0.007), group 2 (P = 0.003), and group 1 (P = 0.0002).

CONCLUSION

Surface roughness and wettability of mini-implants influence their biological response.

Torque Loss in En-Masse Retraction of Maxillary Anterior Teeth Using Miniimplants with Force Vectors at Different Levels: 3D FEM Study

OBJECTIVE

This FEM study was conducted to quantify the amount of torque loss in maxillary anterior teeth by applying force vectors from different levels to the anterior retraction hook at various heights and comparing with that of molar anchorage system.

MATERIALS AND METHODS

Five 3D FEM models were constructed with force vectors at different levels: HOT-High Orthodontic Traction (13.5mm from archwire) to ARH1- Anterior Retraction Hook (5mm), HOT to ARH2 (8mm), LOT- Low Orthodontic Traction (8 mm) to ARH1, LOT to ARH2 and from conventional molar hook to ARH1. Mini-implants were placed buccally between the roots of second premolar and first molar. Torque loss was calculated by measuring the displacement of the teeth at crown tip and root apex in two planes i.e. sagittal and vertical using Y and Z axis respectively in all the five models. The results were statistically analyzed by using Kruskal Wallis ANOVA and Mann-Whitney U-test.

RESULTS

HOT to ARH1 showed that the anterior teeth moved bodily (p =0.5127), followed by molar hook - ARH1(p=0.0495*) which showed mild uncontrolled tipping. Whereas the HOT- ARH2, LOT - ARH1,and LOT - ARH2 models exhibited uncontrolled tipping with maximum torque loss in LOT - ARH1 (p=0.0001*).

CONCLUSION

It can be concluded that bodily movement with very minimal torque loss was observed in HOT-ARH1 model whereas the maximum torque loss was recorded in LOT-ARH2 model. Conventional molar anchorage group showed uncontrolled tipping with some amount of extrusion and anchor loss of posteriors.

En-masse Retraction of the Maxillary Anterior Teeth by Applying Force from Four Different Levels - A Finite Element Study

OBJECTIVE

To find out if it is possible to control maxillary anterior teeth in sagittal and vertical plane during retraction by altering the vertical levels of force application in the posterior region, i.e. identifying the type of movement of the maxillary anterior teeth which occurs when force would be applied from four different levels i.e. High, Medium, and Low pull Implants and from a conventional Molar hook and also to quantify the retraction and intrusion components of force thus setting a guideline for the implant height placement.

MATERIALS AND METHODS

A Finite Element Model of maxillary dentition along with alveolar bone, brackets and wire was developed with defined material properties. The model was analysed to calculate the displacement when force was applied from different levels.

RESULTS

From all points of force application, anterior teeth tipped lingually in the sagittal plane, whereas in the vertical plane extrusion was seen when retracted from molar hook and intrusion was seen when retracted from implants. For every mm of apical displacement of implant, the retraction component of force reduces approximately by around 1% and intrusion component of force increases approximately by around 0.3%.

CONCLUSION

Based on the results of this study we can reckon that by changing the position of implant in vertical plane one will have very little effect on the type of tooth movement. As the point of force application moves apically, type of tooth movement in the sagittal plane remained almost constant and in vertical plane intrusion is slightly increased.

A comparative study between currently used methods and Small Volume-Cone Beam Tomography for surgical placement of mini implants

OBJECTIVE

To compare the outcome of mini implant placement by four different methods: blind placement, a single periapical radiograph (PA), a single panoramic radiograph, and a small-volume cone-beam computed tomography (SV-CBCT). Our hypothesis was that SV-CBCT, with its high resolution, low radiation dose, and three-dimensional depiction of area of interest would yield superior diagnostic information in assessing the potential anchorage site compared to currently used methods that often result in undesired root perforations.

MATERIALS AND METHODS

Potential mini implant sites of 20 dentate or partially dentate human skulls were imaged using three different imaging modalities: PA, panoramic radiograph, and SV-CBCT. Mini implants were placed in 10 maxillary and 10 mandibular randomized sites blindly and using each of the three imaging modalities. Large-volume CBCT scans done postoperatively were used to detect root perforation. Two oral radiologists analyzed the images for perforation of root structures at each site.

RESULTS

There was significantly (P < .05) less root perforation with SV-CBCT when compared with other imaging modalities. Fifty-five percent of mini implants placed blindly, 60% of mini implants placed using PA, and 50% of mini implants placed using a panoramic radiograph perforated a root structure, whereas only 5% of mini implants placed using SV-CBCT perforated a root structure.

CONCLUSIONS

Preoperative evaluation of potential mini implant insertion sites using SV-CBCT aids in predictable placement and results in the least amount of root perforation.

Biomechanics of incisor retraction with mini-implant anchorage

Mini-implants have been successfully incorporated into orthodontic practice all over the world. One of the most popular applications of mini-implant anchorage is to facilitate retraction of the anterior teeth. This article reviews the mechanics involved in anterior tooth retraction with mini-implant supported anchorage. An attempt has been made to synthesize information available in the literature and present it in a manner that is easily understandable from a clinical perspective. We discuss the fundamental differences mini-implant based incisor retraction has when compared to conventional techniques, mechanical factors affecting this process and provide a step-by-step analysis of incisor retraction. In addition, various models of space closure are discussed that have evolved through careful evaluation of in vitro and in vivo experiments.

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.

Effectiveness of en-masse retraction using midpalatal miniscrews and a modified transpalatal arch: Treatment duration and dentoskeletal changes

Objective

The purpose of this study was to compare the treatment duration and dentoskeletal changes between two different anchorage systems used to treat maxillary dentoalveolar protrusion and to examine the effectiveness of en-masse retraction using two miniscrews placed in the midpalatal suture.

Methods

Fifty-seven patients (9 men, 48 women), who had undergone level anchorage system treatment at Aichi-Gakuin University Dental Hospital (Nagoya, Japan) were divided into two groups according to the method of maxillary posterior anchorage reinforcement: midpalatal miniscrews (25 patients, mean age 22 years) and conventional anchorage (32 patients, mean age 19 years). The en-masse retraction period, overall treatment duration, pre-treatment effective ANB angle, and change in the effective ANB angle were compared with an independent-samples t-test.

Results

Compared to the headgear group, the duration of en-masse retraction was longer by approximately 4 months in the miniscrew group (p < 0.001). However, we found no significant difference in the total treatment duration between the groups. Moreover, a greater change in the effective ANB angle was observed in patients treated with miniscrews than in those treated with the conventional method (p < 0.05).

Conclusions

The level anchorage system treatment using miniscrews placed in the midpalatal area will allow orthodontists more time to control the anterior teeth during en-masse retraction, without increasing the total treatment duration. Furthermore, it achieves better dentoskeletal control than does the conventional anchorage method, thereby improving the quality of the treatment results.

Midpalatal miniscrews and high-pull headgear for anteroposterior and vertical anchorage control: cephalometric comparisons of treatment changes

INTRODUCTION

Our aim was to evaluate which anchorage system is better suited for both anteroposterior and vertical anchorage control of maxillary posterior teeth.

METHODS

Fifty-one subjects requiring maximum anchorage were divided into 2 groups according to maxillary posterior anchorage reinforcement: high-pull headgear, conventional transpalatal arch, and interarch elastics (n = 28); or modified transpalatal arch supported by 2 midpalatal miniscrews (n = 23). Bilateral maxillary first premolars were extracted in all patients. Pretreatment and posttreatment lateral cephalometric radiographs were superimposed to compare skeletal and dental changes between the groups.

RESULTS

(1) The miniscrew group had less mesial movement of the maxillary first molars (0.85 vs 3.63 mm) and greater maxillary incisor retraction (6.87 vs 4.50 mm) than did the headgear group with the same treatment duration. (2) The maxillary molars were significantly intruded in the miniscrew group (1.30 mm), whereas they were extruded in the headgear group (0.71 mm). In the miniscrew group, intrusion of the maxillary molars resulted in a statistically significant decrease in the mandibular plane angle (0.80°). Patients using high-pull headgear showed no significant decrease in these measurements.

CONCLUSIONS

In both the anteroposterior and vertical directions, a modified transpalatal arch supported by 2 midpalatal miniscrews provided more stable anchorage.

Three-dimensional soft-tissue and hard-tissue changes in the treatment of bimaxillary protrusion

INTRODUCTION

Facial convexity related to bimaxillary protrusion is prevalent in many populations. Underlying skeletal protrusion combined with increased dentoalveolar protrusion contributes to facial muscle imbalance and lip incompetence, which is undesirable for many patients. In this study, we evaluated the relationship between soft-tissue and hard-tissue changes in an orthodontically treated Asian population.

METHODS

Twenty-four consecutive adult Asian patients (mean age, 24 years), diagnosed with severe bimaxillary dentoalveolar protrusion, were evaluated using pretreatment and posttreatment cone-beam computed tomography. The patients were treated with 4 first premolar extractions followed by anterior retraction with either skeletal or intraoral anchorage. Serial cone-beam computed tomography radiographs were registered on the entire cranial base and fossa. Soft-tissue and hard-tissue changes were determined through landmark displacement and color mapping.

RESULTS

Upper lip retraction was concentrated between the nasolabial folds and commissures. Lower lip retraction was accompanied by significant redistribution of soft tissues at pogonion. Soft-tissue changes correlated well with regional facial muscle activity. Significant retractions (2-4 mm) of the soft tissues occurred beyond the midsagittal region. Use of skeletal anchorage resulted in 1.5 mm greater lower lip retraction than intraoral anchorage, with greater retraction of the maxillary and mandibular incisor root apices.

CONCLUSIONS

Profound soft-tissue changes accompanied retraction of the anterior dentition with both treatment modalities.

Contemporary orthodontics: the micro-screw

Micro-screws (MSs) have gained rapid popularity among orthodontic specialists over the past decade. Subsequently, as general dental practitioners (GDPs) continue to provide general care for patients undergoing orthodontic treatment they are likely to encounter MSs. This article is aimed at GDPs and provides an overview of MS design, placement, removal and safety. Two examples of treated cases will also be used to demonstrate the use of MSs in contemporary orthodontic practice.

Changes in facial profile after maxillomandibular advancement surgery for obstructive sleep apnea syndrome

The aim of this study was to assess changes in the profile of adult male patients treated for obstructive sleep apnea syndrome (OSAS) with maxillomandibular advancement (MMA) surgery and to measure patient perception of changes compared with that of different panels.

MATERIALS AND METHODS

Fifteen consecutive apneic patients displaying a wide variety of morphological types, mean age 42 years (20-59), a BMI of 26.60 kg/m(2) (22-29), a mean initial Apnea Hypopnea Index (AHI) of 50.9 (19-85), underwent MMA. Assessment was done by facial photography, lateral cephalographs (Tweed analysis modified by Riley and Delaire architectural analysis), polysomnographic records and a validated self-assessment questionnaire. Patients' pre- and postoperative profiles were taken from photographs using Photoshop 7™ software. Their darkened outlines were shown randomly in positions A or B (pre- and postoperative) to panels composed of orthodontists (n=40), fine arts students (n=50) and lay persons (n=50) who were requested to choose the most attractive profiles.

RESULTS

The MMA success rate for OSAS was 80% (12/15) for an AHI less than 15, with no surgical complications. All patients reported a reduction of their symptoms and 14 out of 15 were satisfied with the esthetic outcome. Mean advancement was 8.4mm (3.0-10.0) for the maxilla and 10.8mm (10.0-13.0) for the mandible. Following MMA, 12 out of 15 exhibited maxillary protrusion and six out of 15 mandibular protrusion. The mean change in the nasolabial angle was -5.7° (-27°; 14°). The postoperative profiles were preferred by 85% of the combined panels (P=<0.001), showing no significant difference from one panel to another. No skeletal characteristic could be correlated with the esthetic preference. Upper lip retrusion, open nasolabial angle and dolichofacial type emerged as positive preoperative predictors of esthetic preference.

CONCLUSION

The profile changes following MMA were favorably perceived in the majority of cases. However, specific orthodontic preparation could be offered to patients with pronounced preoperative protrusion.

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.

Finite element analysis of the effect of force directions on tooth movement in extraction space closure with miniscrew sliding mechanics

INTRODUCTION

Miniscrews placed in bone have been used as orthodontic anchorage in extraction space closure with sliding mechanics. The movement patterns of the teeth depend on the force directions. To move the teeth in a desired pattern, the appropriate direction of force must be selected. The purpose of this article is to clarify the relationship between force directions and movement patterns.

METHODS

By using the finite element method, orthodontic movements were simulated based on the remodeling law of the alveolar bone. The power arm length and the miniscrew position were varied to change the force directions.

RESULTS

When the power arm was lengthened, rotation of the entire maxillary dentition decreased. The posterior teeth were effective for preventing rotation of the anterior teeth through an archwire. In cases of a high position of a miniscrew, bodily tooth movement was almost achieved. The vertical component of the force produced intrusion or extrusion of the entire dentition.

CONCLUSIONS

Within the limits of the method, the mechanical simulations demonstrated the effect of force direction on movement patterns.

Mechanism of Class II correction in prepubertal and postpubertal patients with Twin Force Bite Corrector

OBJECTIVE

To compare the dentoskeletal effects and treatment efficiency of the Twin Force Bite Corrector (TFBC) appliance in Class II correction of patients treated before or after the pubertal growth spurt.

MATERIALS AND METHODS

Forty-one normodivergent Class II patients treated with the TFBC appliance were divided into two groups based on their cervical vertebral maturation stage (CVMS). Group 1 (G1) consisted of 23 patients (mean age 12.44 ± 1.59 years) where treatment was initiated before the pubertal growth spurt (CVMS I and II), while group 2 (G2) consisted of 18 patients (mean age 13.76 ± 1.44 years) where treatment was started after the pubertal growth spurt (CVMS III to V). Dentoskeletal measurements were made on lateral cephalograms taken before (T1) and after orthodontic treatment (T2).

RESULTS

During treatment, G1 had significantly greater skeletal correction than G2, with more dentoalveolar effects being observed in G2 than G1. However, on comparing both groups at the end of treatment (T2) when growth is complete, no differences in the parameters measured were observed. Overall, treatment time was significantly longer for G1 (3.67 ± 1.45 years) compared to G2 (2.75 ± 1.07 years).

CONCLUSIONS

There is no difference in overall dentoskeletal effects obtained at the end of treatment by the TFBC appliance in normodivergent prepubertal vs postpubertal patients. However, treatment efficiency based on treatment timing is significantly greater for the postpubertal group.

A dynamic analysis of the display of the dentition during speech

The aim of this prospective study was to quantify the display of the dentition through the soft tissue frame during speech using videography for different age groups. Two hundred and sixty-one subjects were initially screened and were divided into five groups: group 1 (G1) (15-19 years), G2 (20-29 years), G3 (30-39 years), G4 (40-49 years), and G5 (≥ 50 years). Groups were also made on the basis of gender and history of orthodontic treatment. Video equipment was used to capture video and each frame was analysed out of which two frames that best represented the maximal display of maxillary incisors (MDMI) during speech and the widest transverse display of dentition (WTDD) during speech were selected. The data obtained was analysed using one-way analyses of variance with Fisher's least significant difference post hoc test. MDMI and WTDD were found to be highly significant during speech across all age groups (P < 0.05). G1-G3 displayed approximately similar levels of maxillary incisor (P > 0.05) but was greater (P < 0.05) than G4 and G5. The buccal corridor showed significant differences as a function of age (P < 0.05). Orthodontic treatment had a significant impact on the display of the maxillary incisors (P < 0.05) but not on the buccal corridors (P > 0.05). Mandibular incisor display was relatively stable across G1-G3, increasing only for G4 and G5. It appears that the maximum display of maxillary incisors decreases with age and the decline is particularly rapid with increasing age. Females tend to display more teeth both in the transverse and vertical directions.

Effect of play between bracket and archwire on anterior tooth movement in sliding mechanics: A three-dimensional finite element study

OBJECTIVES

The aim of this study was to clarify the effect of the play between the bracket and the archwire on anterior tooth movement subjected to the retraction force from various lengths of power arms in sliding mechanics.

MATERIALS AND METHODS

A three-dimensional finite element method was used to simulate en masse anterior tooth retraction in sliding mechanics. The displacements of the maxillary incisor and the archwire deformation were calculated when the retraction force was applied.

RESULTS

When a play did not exist, bodily movement was obtained at 5.0 mm length of power arm. In case a play existed, bodily movement was observed at the power arm length of 11.0 mm.

CONCLUSIONS

In the actual clinical situation, a bracket/archwire play and the torsion of the archwire within the bracket slot should be taken into consideration to prescribe an optimal power arm length and to achieve effective anterior tooth movement.

Displacement pattern of the maxillary arch depending on miniscrew position in sliding mechanics

INTRODUCTION

This clinical study was performed to evaluate the anteroposterior and vertical displacement patterns of the maxillary teeth in sliding mechanics depending on the position of interradicular miniscrews after the extraction of premolars.

METHODS

Thirty-six women requiring maximum incisor retraction because of bialveolar protrusion were divided into 2 groups: group A (n = 18), miniscrew between the premolar and the molar, and group B (n = 18), miniscrew between the premolars. Cephalometric measurements for skeletal and dental changes were made before and after space closure.

RESULTS

In both groups, significant incisor retraction with intrusion of the root apex was noted, with no significant change in the first molar position. Group B displayed significantly greater intrusion at both the incisal tip (1.59 ± 1.53 mm) and the root apex (2.89 ± 1.59 mm) than did group A. In spite of the mean reduction of the vertical skeletal measurements, we failed to find significant skeletal changes.

CONCLUSIONS

Miniscrews provided firm anchorage for anterior retraction. Selection of the placement site appeared to be an important determinant for the resultant displacement pattern of the incisor segment. Discriminative intrusion or retraction might be obtained via strategic miniscrew positioning.

Patient expectations, acceptance and preferences in treatment with orthodontic mini-implants. A randomly controlled study. Part I: insertion techniques

OBJECTIVE

The objective of this study was to compare two different insertion techniques as well as two different anesthesia injection methods carried out on patients undergoing orthodontic treatment with mini-implants to reinforce skeletal anchorage.

PATIENTS AND METHODS

A total of 30 patients were enrolled and randomly divided into two groups, A and B. For the patients in group A the mini-implants were inserted manually after pre-drilling with a dental handpiece. In group B self-drilling mini-implants were inserted without pre-drilling. Furthermore, all patients were given a local anesthetic injected into the root tip area in the second quadrant. In the first quadrant the anesthetic was injected directly next to the insertion region. The patients were questioned concerning pain perception prior to, immediately after, and 1 day after the treatment.

RESULTS

There were no significant differences between the two groups in the degree of discomfort described by the patients. While patients in group A considered the noise from the dental handpiece as the main discomfort factor, patients in group B reported that the pressure applied when inserting the self-drilling mini-implants was the main source of discomfort. Overall discomfort from injections immediately next to the mini-implant insertion area was lower than that resulting from the standard injection methods, where the longer lasting anesthesia was considered unpleasant.

CONCLUSION

Patients tolerated the various insertion procedures equally well. However, there were differences with regard to the injection technique: The patients favored an injection immediately next to the mini-implant insertion area.

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.

Mini-implants vs fixed functional appliances for treatment of young adult Class II female patients: a prospective clinical trial

OBJECTIVE

To compare the treatment effects of maxillary anterior teeth retraction with mini-implant anchorage in young adults with Class II division 1 malocclusion undergoing extraction of the maxillary first premolars with similar patients treated by a fixed functional appliance.

MATERIALS AND METHODS

Thirty-four young adult female patients (mean age 16.5 ± 3.2 years, overjet ≥ 6 mm) with a Class II division 1 malocclusion were divided into two groups: group 1 (G1), in which overjet correction was obtained with a fixed functional appliance (FFA), and group 2 (G2), in which upper first premolars were extracted, followed by space closure with MIs as anchor units. Dentoskeletal and soft tissue changes were analyzed on lateral cephalograms taken before (T1) and after (T2) correction of the overjet.

RESULTS

Both methods were useful in improving the overjet and interincisal relationships. Extrusion and mesial movement of the lower molar, together with lower incisor proclination, were noted in G1. G2 showed distalization and intrusion of the upper molar. The nasio-labial angle became more obtuse in G2, while lower lip protrusion was seen for G1.

CONCLUSIONS

The two treatment protocols provided adequate dental compensation for the Class II malocclusion, but did not correct the skeletal discrepancy. There were significant differences in the dental and soft tissue treatment effects between the two treatment protocols.

Cephalometric comparison of vertical changes between Begg and preadjusted edgewise appliances

The purpose of this retrospective study was to quantify and compare the vertical dimensional changes in bialveolar dental protrusion patients undergoing extraction of all four first premolars between the preadjusted edgewise appliance (PEA) and the Begg appliance. The cephalometric records of 55 patients (14 males and 41 females) with Class I bimaxillary protrusion were selected and divided into two groups based on the appliance used, i.e Begg or PEA mechanotherapy. To minimize the effects of growth, the subjects were at least in stage VI of skeletal maturation. The mean age was 18.25 ± 3.2 years for the Begg group and 18.03 ± 3.5 years for the PEA group. Skeletal and dental changes were analysed in both groups on lateral cephalograms taken pre- (T1) and post- (T2) treatment. A Student's t-test was used to analyse the treatment changes. Within group results showed a significant increase in face height and extrusion and mesial movement of the upper and lower molars for both groups. However, no significant differences were observed when the groups were compared. A significant correlation was found between the change in lower molar to mandibular plane angle and lower anterior face height for both groups. No significant difference was found when the Begg mechanotherapy was compared to the PEA technique on vertical dimensional changes. It can be speculated that mesial movement of the molars tended to keep pace with their extrusion and negated any bite opening effect with both mechanotherapies.

Expectations, acceptance, and preferences regarding microimplant treatment in orthodontic patients: A randomized controlled trial

INTRODUCTION

In this study, we evaluated the pain and discomfort experienced by orthodontic patients by comparing how they rated pain associated with had microimplant placement, tooth extraction, and gingival tissue removal in preparation for implant placement.

METHODS

Fifty-six microimplants were placed in 28 consecutive orthodontic patients for anchorage reinforcement in the maxilla for en-masse retraction. For all patients, extractions of maxillary, or maxillary and mandibular, premolars had been planned. The recruited patients were randomized into 2 groups according to the timing of the extractions. In group A, at least 1 extraction was performed during the evaluation period; the extractions in group B were after the evaluations. Furthermore, all patients had 2 different surgical procedures for placement. On 1 side, the gingival tissue was removed before placement. On the contralateral side, the implant was placed transgingivally. Each patient's perception of pain and discomfort was evaluated by a questionnaire before, immediately after, and 1 week after the intervention.

RESULTS

The discomfort experienced during the extractions was described as very painful by 50% of the patients. It was significantly greater than during tissue removal and microimplant placement (P <0.05). Microimplant placement produced no pain in 30% of the patients and was described as the least painful procedure (P <0.05). Transgingival microimplant placement was significantly preferred by all patients (P <0.05).

CONCLUSIONS

Microimplant surgery seems to be a well-accepted treatment option in orthodontic patients, with significantly lower pain levels than for tooth extractions. Furthermore, transgingival placement is clearly favored by patients who do not need tissue removed before placement.