A prospective study of Twin-block appliance therapy assessed by magnetic resonance imaging

Three-dimensional spatial analysis of temporomandibular joint in adolescent Class II division 1 malocclusion patients: comparison of Twin-Block and clear functional aligner

BACKGROUND

Our study aimed to use three-dimensional (3D) spatial morphological measurement methods to compare the influence of Twin-Block and clear functional aligners on the temporomandibular joint (TMJ) of adolescent Class II division 1 malocclusion mandibular retraction patients. We also aimed to explore the similarities and differences in the effects on the TMJ upon using Twin-Block and clear functional aligner.

METHODS

Cone-beam computed tomography (CBCT) data of 49 patients with Class II division 1 malocclusion (Twin-Block group: 24; clear functional aligner group: 25) were collected before and after functional orthodontic treatment, and a 3D model of the TMJ was reconstructed using MIMICS 21.0 software. Eighteen measurement parameters, including the anterior, superior, and posterior joint spaces, were measured and compared using the 3D model.

RESULTS

After the two groups underwent functional appliance treatment, the height, volume, and surface area of the condyle, length of the mandibular ramus and mandibular length increased; The retro-displaced condyle moved to the middle position of the articular fossa, while the rest of the condylar position did not change significantly. Remodeling of the articular fossa after treatment was not evident. The superior joint space of the clear functional aligner group increased, but there was no significant change after Twin-Block appliances treatment.

CONCLUSIONS

Both appliances promote condylar growth and sagittal and vertical development of the mandible in adolescent Class II division 1 malocclusion mandibular retraction patients. The length of the mandibular ramus showed a more significant increase following treatment with the Twin-Block appliances than with clear function aligners.

Temporomandibular disorders and neck pain in primary headache patients: a retrospective machine learning study

OBJECTIVES

To evaluate the linkage underpinning different clinical conditions as painful TMD and neck pain in patients affected by primary headaches.

MATERIALS AND METHODS

In this machine learning study, data from medical records of patients with headaches as migraine, tension-type headache (TTH) and other primary ones, referring to a University Hospital over a 10-year period were analysed. VAS was used to evaluate the intensity of the TMD and neck pain. Moreover, the magnetic resonance imaging was used to supplement the clinical data.

RESULTS

A total of 300 patients (72 male, 228 female), mean aged 37.78 ± 5.11 years, were included. Higher TMD and neck pain VAS in migraine patients were reported. The machine learning analysis focussed on type of primary headache demonstrated that a higher TMD VAS was correlated to migraine, whereas a higher neck pain VAS was correlated to TTH or migraine. Concerning the TMD type, arthrogenous and mixed TMD were correlated to mild-moderate TMD pain (depending on neck pain intensity), whereas myogenic TMD was correlated to moderate-severe TMD pain.

CONCLUSIONS

Machine-learning approach highlighted the complexity of diagnosis process and demonstrated that neck pain might be an influential variable on the belonging to different group of headaches in TMD patients.

Evaluation of Changes in Soft and Hard Tissues of TMJ among Class II Division 2 Patients after Prefunctional Orthodontics and Twin Block Functional Appliance Therapy: A Prospective MRI Study

Introduction

No study has been conducted to explore soft and hard tissue changes brought by functional appliances within the temporomandibular joint (TMJ) after correction of class II division 2 (div 2) malocclusion. Hence, we planned this study to evaluate the mandibular condyle disk-fossa relationship before and after prefunctional and twin block therapy using a magnetic resonance imaging (MRI) scan.

Methodology

This prospective observational study was conducted among 14 males treated with prefunctional appliances for 3-6 months, followed by 6-9 months of fixed mechanotherapy. MRI scan was evaluated for changes in the TMJ at baseline after completion of prefunctional phase and after completion of functional appliance therapy.

Results

At pretreatment, there was a flat contour on the posterosuperior surface of the condyles and a notch-like projection on its anterior surface. After functional appliance therapy, slight convexity appeared on the posterosuperior surface of the condyle and the prominence of the notch was reduced. There was a statistically significant anterior shift of condyles both after prefunctional and twin block treatment. The meniscus on both sides had significantly shifted posteriorly over three stages with respect to the posterior condylar (PC) plane and Frankfort horizontal (FH) plane. The superior joint space had significantly increased with significant linear glenoid fossa displacement between pre and posttreatment stages.

Conclusion

Prefunctional orthodontics induced favorable changes in TMJ soft and hard tissues of patients, but they were not sufficient to place the soft and hard tissues in their normal positions. A functional appliance phase is needed to place the TMJ in their respective normal positions.

How to cite this article

Patel B, Kukreja MK, Gupta A, et al. Evaluation of Changes in Soft and Hard Tissues of TMJ among Class II Division 2 Patients after Prefunctional Orthodontics and Twin Block Functional Appliance Therapy: A Prospective MRI Study. Int J Clin Pediatr Dent 2022;15(5):479-488.

Three-dimensional comparative evaluation of articular disc position and other temporomandibular joint morphology in Class II horizontal and vertical cases with Class I malocclusion

OBJECTIVE

To evaluate and compare articular disk position, condylar position, and joint spaces in Class II vertical, Class II horizontal, and Class I cases. The purpose was to assess the potential for development of temporomandibular disorders (TMDs) in the three groups.

MATERIALS AND METHODS

A sample of 75 cases, 25 cases in each group of Class I, Class II vertical, and Class II horizontal, were selected based on inclusion and exclusion criteria. Magnetic resonance imaging (MRI) assessments were made with a 1.5-Tesla basic system with a closed-mouth technique for evaluating articular disk position in the sagittal and transverse planes, condylar position, and joint spaces in the sagittal plane. Philips 3.0 software was used to analyze the MR images.

RESULTS

There was evidence of alterations in the temporomandibular joint (TMJ) morphology in both Class II vertical and Class II horizontal cases, with maximum discrepancy in Class II vertical cases. MRI evaluation suggested a tendency for antero-medial disk displacement with anteriorly positioned condyles in Class II vertical cases. The discrepancy was milder in the Class II horizontal group.

CONCLUSIONS

Class II vertical cases are more susceptible to the development of TMDs and should be subjected to TMJ evaluation before starting any orthodontic treatment to intercept and prevent a mild asymptomatic TMD from developing into a more severe form. Class II vertical cases should be subjected to MRI evaluation before starting any orthodontic treatment.

What effect does functional appliance treatment have on the temporomandibular joint? A systematic review with meta-analysis

BACKGROUND

The aim of the current systematic review was to compare the radiologic effects of functional appliance Class II treatment compared to no treatment on the temporomandibular joint and its components.

METHODS

Nine databases were searched up to June 2019 for randomized or prospective non-randomized clinical trials comparing Class II patients treated with functional appliances to untreated patients. After duplicate study selection, data extraction, and risk of bias assessment with the Cochrane tool and the ROBINS-I tool, random effects meta-analyses of mean differences (MDs) and their 95% confidence intervals (CIs) were performed, followed by the assessment of the quality of evidence with GRADE.

RESULTS

A total of 11 papers on 8 unique trials with 377 patients (39.8% male; average age 10.3 years) were finally included. Limited evidence indicated that compared to untreated growing patients functional appliance treatment was associated with increased condylar width (2 studies; MD 1.1 mm; 95% CI 0.1 to 2.2 mm; very low evidence quality), decreased anterior joint space (2 studies; MD - 0.7 mm; 95% CI - 0.5 to - 0.9 mm; very low evidence quality), increased superior joint space (2 studies; MD 0.7 mm; 95% CI 0.5 to 1.0 mm; very low evidence quality), increased posterior joint space (2 studies; MD 1.0 mm; 95% CI 0.9 to 1.2 mm; very low evidence quality), and vertical displacement of the glenoid fossa (2 studies; MD 0.4 mm; 95% CI 0.1 to 0.7 mm; very low evidence quality). The main limitations affecting the validity of the present findings were the inclusion of non-randomized studies with methodological issues, imprecision due to limited samples of the included studies, and inconsistencies among studies.

CONCLUSIONS

Currently existing evidence from controlled clinical studies on humans indicates that functional appliance treatment is associated with positional and skeletal alterations of the temporomandibular joint in the short term compared to untreated controls. However, the clinical relevance of these changes remains unclear, while the quality of existing evidence is low due to methodological issues of existing studies.

REVIEW REGISTRATION

PROSPERO, CRD42018109271.

Effects of Low-Intensity Pulsed Ultrasound Therapy on the Temporomandibular Joint Complex in Conjunction With a Fixed Functional Appliance: A Prospective 3-Dimensional Cone Beam Computed Tomographic Study

OBJECTIVES

This prospective study aimed to analyze 3-dimensional changes in the temporomandibular joint (TMJ) complex with a synergistic effect of functional jaw orthopedics using a fixed functional appliance and low-intensity pulsed ultrasound (LIPUS) therapy.

METHODS

Forty patients with skeletal class II malocclusion were randomly assigned to 4 groups (2 control groups and 2 test groups) of 10 patients each. After insertion of the fixed functional appliance, the test group was stimulated with LIPUS therapy in the TMJ region bilaterally for 20 minutes daily for first 10 days and thereafter at least 3 times per week until complete mandibular advancement was achieved. Three-dimensional images obtained with a cone beam computed tomographic scanner were used to analyze the changes in the TMJ complex at the prefunctional stage and after completion of functional appliance therapy. Direct intragroup and intergroup comparisons for different morphometric variables were conducted with the Student t test.

RESULTS

The 40 patients included 20 male and 20 female patients between the ages of 12 and 16 years (mean age ± SD, 13.2 ± 1.8 years). Both the test groups and the control groups showed statistically significant variable changes in condylar head position and morphometric changes in relation to the joint space analysis (mean differences, -1.000 and -1.080 mm; P < .05). However, no significant differences were found during the intergroup comparisons at the prefunctional and postfunctional stages for the variables examined, except for the measurements of the linear distance of the condyle to the external auditory meatus on both the right and left sides at the prefunctional phase.

CONCLUSIONS

Low-intensity pulsed ultrasound therapy positively affects the quantum of the joint space, thus proving to be a promising adjunct in enhancing treatment outcomes of functional jaw orthopedics in growing patients with skeletal class II malocclusions.

Are morphologic and topographic alterations of the mandibular fossa after fixed functional treatment detectable on tomograms? Visual classification and morphometric analysis

AIM

The goal was to evaluate if changes in morphology and topography of the mandibular fossa after Functional Mandibular Advancer (FMA) treatment are detectable on tomograms. Furthermore, the suitability of digital tomograms (DT) over magnetic resonance imaging (MRI) for this particular question was investigated.

MATERIALS AND METHODS

In all, 25 patients (14 female, 11 male) with a skeletal class II malocclusion received treatment with a FMA. DTs were available prior to (T1) and after (T2) FMA treatment. A total of 50 temporomandibular joints were investigated. The mandibular fossae were evaluated metrically and visually regarding treatment-induced alterations. A p < 0.05 was set as the level for statistical significance for all tests. Results were compared to the results of a recent MRI study.

RESULTS

Visual inspection of all 50 joints in the DT at T1 and T2 revealed no alterations of the fossa shape in the sagittal plane; 24 patients showed identical morphology of right and left joints. The metrical analysis revealed no significant changes regarding width, depth and ratio thereof between T1 and T2. There also were no bilateral differences. Another 18 different distance measurements between porion, mandibular fossa, articular eminence and pterygoid fossa showed no significant changes. There was no detectable proof of a fossa shift.

CONCLUSIONS

No changes in the sagittal plane, mandibular fossa, the articular tubercle, or a possible fossa shift were found in the DT of class II patients after FMA treatment. DT and MRI measurements and the visual inspection revealed identical findings; thus, DT appears to be a valuable research tool for sagittal analysis of mandibular fossa changes.

Temporomandibular disorders in growing patients after treatment of class II and III malocclusion with orthopaedic appliances: a systematic review

OBJECTIVE

To determine if the use of orthopaedic appliances in growing patients applied to correct Class II and III malocclusion is related to the development of temporomandibular disorders (TMD).

MATERIAL AND METHODS

A systematic review was conducted between 1960 and July 2017, based on electronic databases: PubMed, Cochrane Library, Embase, Medline, Scopus, EBSCOhost, Scielo, Lilacs and Bireme. Controlled clinical trials (CCTs) and randomized controlled trials (RCTs) were identified. The articles were selected and analyzed by two authors independently. The quality of the evidence was determined according to the guidelines of the Cochrane Risk Bias Assessment Tool and the Cochrane Quality Study Guide.

RESULTS

Seven articles were included, four CCTs and three RCTs. The studies were grouped according to malocclusion treatment in (a) class II appliances (n = 4) and (b) class III appliances (n = 3). The quality of evidence was low due to the high risk of bias, independent of the association reported. All studies concluded that the use of orthopaedic appliances would not contribute to the development of TMD.

CONCLUSIONS

The quality of evidence available is insufficient to establish definitive conclusions, since the studies were very heterogeneous and presented a high risk of bias. However, it is suggested that the use of orthopaedic appliances to correct class II and III malocclusion in growing patients would not be considered as a risk factor for the development of TMD. High-quality RCTs are required to draw any definitive conclusions.

Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children and adolescents

BACKGROUND

Prominent upper front teeth are a common problem affecting about a quarter of 12-year-old children in the UK. The condition develops when permanent teeth erupt. These teeth are more likely to be injured and their appearance can cause significant distress. Children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of their teeth. If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait and provide treatment in adolescence.

OBJECTIVES

To assess the effects of orthodontic treatment for prominent upper front teeth initiated when children are seven to 11 years old ('early treatment' in two phases) compared to in adolescence at around 12 to 16 years old ('late treatment' in one phase); to assess the effects of late treatment compared to no treatment; and to assess the effects of different types of orthodontic braces.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 27 September 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 8), MEDLINE Ovid (1946 to 27 September 2017), and Embase Ovid (1980 to 27 September 2017). The US National Institutes of Health Ongoing Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Randomised controlled trials of orthodontic treatments to correct prominent upper front teeth (Class II malocclusion) in children and adolescents. We included trials that compared early treatment in children (two-phase) with any type of orthodontic braces (removable, fixed, functional) or head-braces versus late treatment in adolescents (one-phase) with any type of orthodontic braces or head-braces, and trials that compared any type of orthodontic braces or head-braces versus no treatment or another type of orthodontic brace or appliance (where treatment started at a similar age in the intervention groups).We excluded trials involving participants with a cleft lip or palate, or other craniofacial deformity/syndrome, and trials that recruited patients who had previously received surgical treatment for their Class II malocclusion.

DATA COLLECTION AND ANALYSIS

Review authors screened the search results, extracted data and assessed risk of bias independently. We used odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous outcomes, and mean differences (MDs) and 95% CIs for continuous outcomes. We used the fixed-effect model for meta-analyses including two or three studies and the random-effects model for more than three studies.

MAIN RESULTS

We included 27 RCTs based on data from 1251 participants.Three trials compared early treatment with a functional appliance versus late treatment for overjet, ANB and incisal trauma. After phase one of early treatment (i.e. before the other group had received any intervention), there was a reduction in overjet and ANB reduction favouring treatment with a functional appliance; however, when both groups had completed treatment, there was no difference between groups in final overjet (MD 0.21, 95% CI -0.10 to 0.51, P = 0.18; 343 participants) (low-quality evidence) or ANB (MD -0.02, 95% CI -0.47 to 0.43; 347 participants) (moderate-quality evidence). Early treatment with functional appliances reduced the incidence of incisal trauma compared to late treatment (OR 0.56, 95% CI 0.33 to 0.95; 332 participants) (moderate-quality evidence). The difference in the incidence of incisal trauma was clinically important with 30% (51/171) of participants reporting new trauma in the late treatment group compared to only 19% (31/161) of participants who had received early treatment.Two trials compared early treatment using headgear versus late treatment. After phase one of early treatment, headgear had reduced overjet and ANB; however, when both groups had completed treatment, there was no evidence of a difference between groups in overjet (MD -0.22, 95% CI -0.56 to 0.12; 238 participants) (low-quality evidence) or ANB (MD -0.27, 95% CI -0.80 to 0.26; 231 participants) (low-quality evidence). Early (two-phase) treatment with headgear reduced the incidence of incisal trauma (OR 0.45, 95% CI 0.25 to 0.80; 237 participants) (low-quality evidence), with almost half the incidence of new incisal trauma (24/117) compared to the late treatment group (44/120).Seven trials compared late treatment with functional appliances versus no treatment. There was a reduction in final overjet with both fixed functional appliances (MD -5.46 mm, 95% CI -6.63 to -4.28; 2 trials, 61 participants) and removable functional appliances (MD -4.62, 95% CI -5.33 to -3.92; 3 trials, 122 participants) (low-quality evidence). There was no evidence of a difference in final ANB between fixed functional appliances and no treatment (MD -0.53°, 95% CI -1.27 to -0.22; 3 trials, 89 participants) (low-quality evidence), but removable functional appliances seemed to reduce ANB compared to no treatment (MD -2.37°, 95% CI -3.01 to -1.74; 2 trials, 99 participants) (low-quality evidence).Six trials compared orthodontic treatment for adolescents with Twin Block versus other appliances and found no difference in overjet (0.08 mm, 95% CI -0.60 to 0.76; 4 trials, 259 participants) (low-quality evidence). The reduction in ANB favoured treatment with a Twin Block (-0.56°, 95% CI -0.96 to -0.16; 6 trials, 320 participants) (low-quality evidence).Three trials compared orthodontic treatment for adolescents with removable functional appliances versus fixed functional appliances and found a reduction in overjet in favour of fixed appliances (0.74, 95% CI 0.15 to 1.33; two trials, 154 participants) (low-quality evidence), and a reduction in ANB in favour of removable appliances (-1.04°, 95% CI -1.60 to -0.49; 3 trials, 185 participants) (low-quality evidence).

AUTHORS' CONCLUSIONS

Evidence of low to moderate quality suggests that providing early orthodontic treatment for children with prominent upper front teeth is more effective for reducing the incidence of incisal trauma than providing one course of orthodontic treatment in adolescence. There appear to be no other advantages of providing early treatment when compared to late treatment. Low-quality evidence suggests that, compared to no treatment, late treatment in adolescence with functional appliances, is effective for reducing the prominence of upper front teeth.

Treatment with Twin-block appliance followed by fixed appliance therapy in a growing Class II patient

A girl, aged 11 years 4 months, with a skeletal Class II pattern and a severe overjet (10 mm) was treated with a Twin-block appliance. After 9 months of appliance therapy, the skeletal Class II was overcorrected. After 26 months of retention, when the occlusion was stable and the growth rate was diminishing, fixed orthodontic appliances using temporary skeletal anchorage devices were initiated. The total active treatment time with fixed orthodontic appliances was 30 months. Posttreatment records after 18 months demonstrated excellent stability: a functional occlusion and a pleasing facial balance. Cone-beam computed tomography was used to visualize temporomandibular joint adaptations after the functional and fixed orthodontic therapies.

Impact of functional mandibular advancement appliances on the temporomandibular joint - a systematic review

Background

Although many orthodontists have no doubts about the effectiveness of functional appliances for mandibular advancement, the impact on the temporomandibular joint (TMJ) is still in dispute. The objective of this systematic review is to examine the main effects on the TMJ of using functional appliances, both in healthy patients and in patients with a pre-existing disorder.

Material and Methods

A systematic review of the literature was conducted in accordance with the PRISMA guidelines. Only systematic reviews, meta-analyses, randomized clinical trials (RCTs), case-control studies and cohort studies were included. A detailed language-independent electronic search was conducted in the Pubmed, Scopus, Cochrane Library and Embase databases. All studies published between 2000 and 2015 were included.

Results

A total of 401 articles were identified. Of these, 159 were duplicates and were excluded. On reading the title and abstract, 213 articles were excluded because they did not answer the research question, leaving a total of 29 articles. These articles were read and assessed. Following critical reading of the full text, eight articles were excluded: seven because they were considered of low quality and one because it published redundant data. As a result, 21 articles were included.

Conclusions

After treatment with functional appliances, the condyle was found to be in a more advanced position, with remodelling of the condyle and adaptation of the morphology of the glenoid fossa. No significant adverse effects on the TMJ were observed in healthy patients and the appliances could improve joints that initially presented forward dislocation of the disk.

Key words:Temporomandibular joint, TMJ, orthodontic appliances, functional, mandibular advancement, herbst appliance, bionator.

Comparison of temporomandibular joint changes in Twin Block and Bionator appliance therapy: a magnetic resonance imaging study

BACKGROUND

The objective of the present study was to evaluate and compare temporomandibular joint changes especially disk-condyle-fossa relationship following functional treatment of skeletal class II division 1 malocclusion using Twin Block and Bionator appliances.

METHODS

The total sample consisted of 30 subjects (13 males and 17 females) with class II division 1 malocclusion having mandibular retrognathism, in the age group of 9 to 14 years. Two treatment groups, i.e., Twin Block and Bionator groups, were formed which comprised ten subjects each, while a group of ten subjects served as the control group. The treatment effects were evaluated using magnetic resonance imaging (MRI). For the treatment groups, pretreatment MRI with wax construction bite was taken. For all subjects, MRI images with corrected sagittal T1 images were recorded in a maximal intercuspation position at pretreatment (R1) and in an unstrained retruded position at the end of a 6-month observation period (R2).

RESULTS

At the end of 6 months of treatment, the condyles occupied a more anterior position in the fossa to its pretreatment position, while the disk moved more posteriorly in relation to the condyle. The control group showed no changes in the condyle and disk position over a period of 6 months.

CONCLUSIONS

Although the treatment group showed consistent forward positioning of the condyle and backward movement of the disk, long-term MRI findings in these groups will further clarify the adaptations between the condyle fossa and articular disk.

Use of Forsus fatigue-resistant device in a patient with Class I malocclusion and mandibular incisor agenesis

Orthodontic treatment in patients with congenitally missing teeth can be challenging. In this case report, we describe the treatment of a 15-year-old girl with mild dental crowding and 2 congenitally missing mandibular incisors. The Forsus fatigue-resistant device was used to move the mandible and the mandibular teeth forward. A new balanced and stable occlusion was achieved after treatment. When the treatment plan includes moving the mandibular teeth forward in a patient with mandibular incisor agenesis, the profile and the skeletal and dental features should be carefully scrutinized to ensure that balanced and esthetic results are achieved.

Condylar response to functional therapy with Twin-Block as shown by cone-beam computed tomography

OBJECTIVE

To evaluate the condylar changes through cone-beam computed tomography (CBCT) images in patients treated with Twin-Block functional appliance.

MATERIALS AND METHODS

In this retrospective study, CBCT images of 30 patients who were treated with the Twin-Block appliance were used. Mandible was segmented and pretreatment and posttreatment (T0 and T1) condylar volume was compared. The angle between sella-nasion-Point A (SNA), angle between sella-nasion-Point B (SNB), angle between Point A-nasion-Point B (ANB), midfacial length (Co-A), mandibular length (Co-Gn), and the distances from right condylion to left condylion (CoR-CoL) were also measured on three-dimensional images. Differences were analyzed with Wilcoxon signed rank tests, and Mann-Whitney U-tests were used to compare the scores of male and female participants. Significance was set at P < .05.

RESULTS

In this study, a decrease in SNA and ANB (P < .05 and P < .01, respectively) and an increase in SNB (P < .01) were found. Additionally, CoR-CoL, Co-Gn, and condylar volume increased at both the left and right sides (P < .01). However, increase at Co-A was not statistically significant (P > .05). Comparison of differences by sex was not statistically significant for all measurements (P > .05).

CONCLUSION

Twin-Block appliance increases condylar volume, mandibular length, and intercondylar distance by stimulating growth of condyle in an upward and backward direction.

Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children

BACKGROUND

Prominent upper front teeth are a common problem affecting about a quarter of 12-year old children in the UK. The correction of this condition is one of the most common treatments performed by orthodontists. This condition develops when the child's permanent teeth erupt and children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of the teeth. These teeth are more likely to be injured and their appearance can cause significant distress.If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait until the child is older and provide treatment in early adolescence.

OBJECTIVES

To assess the effects of orthodontic treatment for prominent upper front teeth when this treatment is initiated when the child is seven to 11 years old compared to when they are in early adolescence, or when treatment uses different types of orthodontic braces.

SEARCH METHODS

We searched the following databases: Cochrane Oral Health Group's Trials Register (to 17 April 2013), CENTRAL (The Cochrane Library 2013, Issue 3), MEDLINE (OVID) (1946 to 17 April 2013) and EMBASE (OVID) (1980 to 17 April 2013). There were no restrictions regarding language or publication date.

SELECTION CRITERIA

Randomised controlled trials of children and/or adolescents (age < 16 years) on early treatment (either one or two-phase) with any type of orthodontic braces (removable, fixed, functional) or head-braces compared with late treatment with any type of orthodontic braces or head-braces; or, on any type of orthodontic braces or head-braces compared with no treatment or another type of orthodontic brace or appliance (with treatment starting in children of similar ages in both groups) to correct prominent upper front teeth.

DATA COLLECTION AND ANALYSIS

Review authors screened the search results, extracted data and assessed risk of bias independently, used odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous outcomes, mean differences (MDs) and 95% CIs for continuous outcomes and a fixed-effect model for meta-analyses as there were fewer than four studies.

MAIN RESULTS

We included 17 studies based on data from 721 participants.Three trials (n = 343) compared early (two-phase) treatment (7-11 years of age) with a functional appliance, with adolescent (one-phase) treatment. Statistically significant differences in overjet, ANB and PAR scores were found in favour of functional appliance when the first phase of early treatment was compared with observation in the children due to receive treatment in adolescence. However, at the end of treatment in both groups, there was no evidence of a difference in the overjet (MD 0.21, 95% CI -0.10 to 0.51, P = 0.18) (low quality evidence), final ANB (MD -0.02, 95% CI -0.47 to 0.43, P = 0.92), PAR score (MD 0.62, 95% CI -0.66 to 1.91, P = 0.34) or self concept score (MD 0.83, CI -2.31 to 3.97, P = 0.60). However, two-phase treatment with functional appliance showed a statistically significant reduction in the incidence of incisal trauma (OR 0.59, 95% CI 0.35 to 0.99, P = 0.04) (moderate quality evidence). The incidence of incisal trauma was clinically significant with 29% (54/185) of patients reporting new trauma incidence in the adolescent (one-phase) treatment group compared to only 20% (34/172) of patients receiving early (two-phase) treatment.Two trials (n = 285), compared early (two-phase) treatment using headgear, with adolescent (one-phase) treatment. Statistically significant differences in overjet and ANB were found in favour of headgear when the first phase of early treatment was compared with observation in the children due to receive treatment in adolescence. However, at the end of treatment in both groups, there was no evidence of a difference in the overjet (MD 0.22, 95% CI -0.56 to 0.12, P = 0.20) (low quality evidence), final ANB (MD -0.27, 95% CI -0.80 to 0.26, P = 0.32) or PAR score (MD -1.55, 95% CI -3.70 to 0.60, P = 0.16). The incidence of incisal trauma was, however, statistically significantly reduced in the two-phase treatment group (OR 0.47, 95% CI 0.27 to 0.83, P = 0.009) (low quality evidence). The adolescent treatment group showed twice the incidence of incisal trauma (47/120) compared to the young children group (27/117).Two trials (n = 282) compared different types of appliances (headgear and functional appliance) for early (two-phase) treatment. At the end of the first phase of treatment statistically significant differences, in favour of functional appliances, were shown with respect to final overjet only. At the end of phase two, there was no evidence of a difference between appliances with regard to overjet (MD -0.21, 95% CI -0.57 to 0.15, P = 0.26), final ANB (MD -0.17, 95% CI -0.67 to 0.34, P= 0.52), PAR score (MD -0.81, 95% CI -2.21 to 0.58, P = 0.25) or the incidence of incisal trauma (OR 0.79, 95% CI 0.43 to 1.44, P = 0.44).Late orthodontic treatment for adolescents with functional appliances showed a statistically significant reduction in overjet of -5.22 mm (95% CI -6.51 to -3.93, P < 0.00001) and ANB of -2.37° (95% CI -3.01 to -1.74, P < 0.00001) when compared to no treatment (very low quality evidence).There was no evidence of a difference in overjet when Twin Block was compared to other appliances (MD 0.01, 95% CI -0.45 to 0.48, P = 0.95). However, a statistically significant reduction in ANB (-0.63°, 95% CI -1.17 to -0.08, P = 0.02) was shown in favour of Twin Block. There was no evidence of a difference in any reported outcome when Twin Block was compared with modifications of Twin Block.There was insufficient evidence to determine the effects of Activator, FORSUS FRD EZ appliances, R-appliance or AIBP.

AUTHORS' CONCLUSIONS

The evidence suggests that providing early orthodontic treatment for children with prominent upper front teeth is more effective in reducing the incidence of incisal trauma than providing one course of orthodontic treatment when the child is in early adolescence. There appears to be no other advantages for providing treatment early when compared to treatment in adolescence.

Temporomandibular joint changes after activator appliance therapy: a prospective magnetic resonance imaging study

The aim of this prospective clinical and magnetic resonance imaging study was to analyze the effect of 1-year Activator (Yi-fan Dental Co., Shanghai, China) treatment in internal anatomical relationships of the temporomandibular joint (TMJ) complex, including the condyle-disc relationship, condyle-fossa relationship, condylar height change, disc length change, and morphologic change of the glenoid fossa. The study was composed of patients with class II division 1 malocclusion (11 girls and 13 boys) who underwent 1-year Activator treatment. All the patients were in the acceleration or peak phase of the pubertal growth spurt. Magnetic resonance imaging in closed-mouth position and lateral cephalometric radiographs before and after 1 year of Activator treatment were analyzed metrically. Overall, condylar height showed a significant increase (P < 0.001), and the eminence angle decreased (P = 0.037). TMJ disc length has no statistically significant change before and after treatment. A slight advancement (P = 0.041) was found in the sagittal condylar position. A significant backward movement (P = 0.04) was shown in the sagittal disc position. Our results showed that the disc is not impaired by Activator therapy; it seems possible that adaptive remodeling, including a shallower glenoid fossa and increased condylar height, was seen after treatment.

Morphological Changes of Condyles and Helkimo Clinical Dysfunction Index in Patients Treated with Herbst - Orthodontic Appliance

This study evaluated the morphological changes in the temporomandibular joint (TMJ) condyles and calculated the Helkimo clinical dysfunction index (CDI) in adolescents with Class II Division 1 malocclusion and mandibular retrognathism treated with the Herbst appliance (phase I) and fixed orthodontic appliances (phase II). Thirty-two consecutive adolescents underwent phase I, and 23 completed phase II. The TMJs were evaluated qualitatively using magnetic resonance imaging (MRI) at the beginning of treatment (T1), during phase I (T2), at the end of phase I (T3) and at the end of phase II (T4). The CDI was calculated at T1, T3 and T4. From T1 to T3 (p=0.326), there were no changes in condyle morphology in 86.0% of the TMJs. From T3 to T4 (p<0.05) and T1 to T4 (p<0.05), changes occurred in 39.1% and 43.4% of the condyles. No significant changes in CDI occurred from T1 to T3, T3 to T4 and T1 to T4 (p=1.000; 86.6%, 76.2% and 76.2% concordance). After phase I, there were practically no changes in condyle morphology. At the end of phase II, a mild flattening was observed in some condyles. It may be concluded that no significant changes occurred in CDI after both treatment phases.

Analysis of Criteria for MRI Diagnosis of TMJ Disc Displacement and Arthralgia

Aims. To improve diagnostic criteria for TMJ disc displacement (DD). Methods. The standard protocol for MRI diagnosis of DD, using a 12 o'clock reference position, was compared to an alternative protocol. The alternative protocol involves the functional relationship between the condyle and articular eminence, using a line perpendicular to the posterior slope of the eminence as a reference for disc position. The disc location was examined using both protocols, and disc diagnoses were compared in their relationship with joint pain. Statistical analyses included P value, sensitivity, specificity, odds ratio, and kappa statistic. Results. 58 MRIs were interpreted. 36 subjects reported arthralgia; 22 did not. Both protocols demonstrated significance (standard P = 0.004, alternative P < 0.001) for the ability to predict arthralgia. The odds of arthralgia increased in DD patients diagnosed by standard methods 9.71 times and in DD diagnosed by alternative means 37.15 times. The diagnostic sensitivity decreased 30% using the alternative versus the standard protocol (0.6389 versus 0.9444), while specificity increased 60% (0.9545 versus 0.3636). Conclusions. A stronger relationship occurs between DD and arthralgia when using a function-based protocol. The alternative protocol correctly identifies subjects without arthralgia, who by standard methods would be diagnosed with DD, as having nondisplaced discs, providing a more clinically relevant assessment of TMJ disc displacement.

Comparison of treatments with the Forsus fatigue resistant device in relation to skeletal maturity: a cephalometric and magnetic resonance imaging study

INTRODUCTION

The aim of this study was to compare the dentoskeletal changes and alterations of mandibular condyle-disc-fossa relationships in subjects at the peak and the end of the pubertal growth period treated with the Forsus fatigue resistant device (3M Unitek, Monrovia, Calif).

METHODS

The sample consisted of 29 subjects with Class II Division 1 malocclusions who were classified according to their hand-wrist radiographs. Fifteen patients were at or just before the peak phase of pubertal growth (peak pubertal group). Fourteen patients were near the end of the pubertal growth period (late pubertal group). The study was conducted by using lateral cephalometric radiographs and magnetic resonance images obtained at the beginning and at the end of the application of the Forsus fatigue resistant device. The treatment period was 9 months.

RESULTS

The Wilcoxon signed rank test was used to evaluate differences within groups. The changes observed in both groups were compared by using the Mann-Whitney U test. There were statistically significant group differences in mandibular length and ramus length, with significant increases of these parameters in the peak pubertal group (P <0.05). No significant differences were observed between the groups concerning dental parameters (P >0.05), with the exception of mandibular molar vertical movements, which were significantly greater in the peak pubertal group (P <0.05). Analysis of the magnetic resonance images showed no positional changes of the mandibular condyle in relation to the glenoid fossa in either group (P >0.05). Although the articular disc was positioned more anteriorly in the peak pubertal group compared with its pretreatment position (P <0.05), the position of the disc was still within the physiologic range. No significant intergroup difference was observed for disc-condyle relationship (P >0.05).

CONCLUSIONS

The Forsus fatigue resistant device did not appear to cause significant increases in mandibular dimensions in subjects in late puberty. According to the magnetic resonance image findings, Forsus treatment is not a risk factor for the development of temporomandibular dysfunction in subjects with no signs and clinical symptoms of dysfunction.

Temporomandibular joint adaptations following two-phase therapy: an MRI study

AIM

To document the alterations within the condyle-glenoid fossa (C-GF) complex and the positional changes of the glenoid fossa in the cranium after removable functional appliance therapy and after the completion of fixed appliance therapy.

SETTING AND SAMPLE

The Department of Orthodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India. The study sample consisted of 12 growing children (eight girls and four boys) between 10 and 14 years of age with skeletal Class II division 1 malocclusion selected on well defined criteria.

MATERIALS AND METHODS

All patients were treated with either the Twin Block or the Bionator appliance followed by fixed appliances. Mean total treatment duration was 28 months. The changes in and around the C-GF complex were evaluated using MRI at pre-treatment stage, after functional appliance therapy and at the completion of fixed mechanotherapy.

RESULTS

Forward condylar position within the glenoid fossa and articular disc retrusion with respect to the condylar head were statistically significant after functional appliance therapy. However, the condyles had a relatively concentric position within the glenoid fossa, while the articular disc resumed its pre-treatment position at the end of the treatment. Linear measurements from the centre of the external auditory meatus to the post-glenoid spine revealed a 1.3-mm forward relocation of the post-glenoid spine along the Frankfurt Horizontal plane.

CONCLUSIONS

Forward relocation of the C-GF complex seems to be one of the mechanisms of action of functional appliances, while the internal anatomic arrangement within the temporomandibular joint (TMJ) complex normalizes to its pre-treatment position.

Muscular and condylar response to rapid maxillary expansion. Part 2: magnetic resonance imaging study of the temporomandibular joint

INTRODUCTION

In this prospective clinical study, we used bilateral temporomandibular joint (TMJ) magnetic resonance images (MRIs) to investigate the condylar response to rapid maxillary expansion (RME).

METHODS

Bilaterial MRIs of the TMJs of 18 subjects (11 girls, 7 boys; mean age, 12.54 years; range, 9.75-14.8 years) were assessed. All subjects had unilateral or bilateral posterior crossbites involving 3 or more posterior teeth. There was no control group because of the short observation period. The MRI protocol included closed-mouth parasagittal proton density weighted spin echo and fat-suppressed short T1 inversion recovery sequences. The MRIs were taken before treatment (Tx 1), and at 6 weeks (Tx 2) and at 18 weeks (Tx 3) after treatment. Alterations in the signal intensities of the TMJ region were examined visually by a radiologist who was blinded to the subjects' characteristics.

RESULTS

Increased signal intensities appeared as bright areas on the MRIs, indicating red bone marrow edema that is a sign of condylar remodeling. There were no bright areas in the condylar regions at Tx 2 in the 36 TMJs. Bright areas at the condylar region were observed both in proton density and fat-suppressed spin echo sequences at Tx 3 in 32 TMJs. Twenty-two TMJs had bright areas localized at the condylar head, and 10 TMJs had bright areas that extended through both the condyle and the mandibular ramus. No bright areas were seen at Tx 2 or Tx 3 for 4 TMJs.

CONCLUSIONS

A condylar response to RME was observed in 32 TMJs at 18 weeks after expansion. Both the extensive orthopedic and the functional occlusal forces associated with RME have roles in condylar and ramal responses.

Effects of fixed functional appliance treatment on the temporomandibular joint

INTRODUCTION

In this study, we tested the hypothesis that fixed functional appliance treatment in a group of Class II Division 1 patients with mandibular retrusion changes the condyle position in the glenoid fossa.

METHODS

Transverse computed tomography images were taken of the temporomandibular joint region in 60 children with Class II Division 1 malocclusion. Thirty randomly selected patients were treated with a fixed functional orthodontic appliance (Forsus nitinol flat-spring, 3M Unitek Corp, Monrovia, Calif) for 7 months; another 30 patients without treatment were used as controls. Computed tomography images taken at the beginning and end of fixed functional appliance treatment were used for estimating the condyle-glenoid fossa relationship, including the volumes of condyle, glenoid fossa, and anterior and posterior joint spaces.

RESULTS

Although the volumes of the condyle and glenoid fossa increased more in the study group than in the control group, the differences were not statistically significant. However, statistically significant differences were found between the groups in the volumes of the anterior and posterior joint spaces (P < 0.05).

CONCLUSIONS

When the volumes of the anterior and posterior joint spaces changed, the condyle was more posteriorly positioned in the glenoid fossa in the study group than in the control group.

Muscular and condylar response to rapid maxillary expansion. Part 3: magnetic resonance assessment of condyle-disc relationship

INTRODUCTION

The aim of this prospective study was to assess temporomandibular joint (TMJ) condyle-disc positions at the sagittal and coronal planes of magnetic resonance images (MRIs) before and after rapid maxillary expansion (RME).

METHODS

The study included 18 subjects (11 girls, 7 boys) with a mean age of 12.54 years with unilateral or bilateral posterior crossbite that included at least 3 posterior teeth. The clinical and radiographic assessments of the TMJ were done before (T1) and 18 weeks after (T2) RME. A Haas-type expansion appliance was used for an average treatment time of 3.5 weeks.

RESULTS

A visual MRI analysis of pretreatment condyle-disc positions showed that 8 TMJs had medial disc displacement, 3 had anteromedial disc displacement, and 2 had lateral disc displacement. The disc positions remained unchanged at T2 except in 1 subject, who developed unilateral anterior disc displacement. Unilateral joint sounds developed in 3 subjects without changes in the disc positions.

CONCLUSIONS

Posterior crossbite can be considered a minor risk factor for temporomandibular disorder (TMD). RME is neither a risk factor nor a prevention for TMD. Coronal MRIs contribute complementary information for optimal diagnosis of TMD.

Orthodontic treatment for prominent upper front teeth in children

BACKGROUND

Prominent upper front teeth are an important and potentially harmful type of orthodontic problem. This condition develops when the child's permanent teeth erupt and children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of the teeth. If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait until the child is older and provide treatment in early adolescence. When treatment is provided during adolescence the orthodontist may provide treatment with various orthodontic braces, but there is currently little evidence of the relative effectiveness of the different braces that can be used.

OBJECTIVES

To assess the effectiveness of orthodontic treatment for prominent upper front teeth, when this treatment is provided when the child is 7 to 9 years old or when they are in early adolescence or with different dental braces or both.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched. The handsearching of the key international orthodontic journals was updated to December 2006. There were no restrictions in respect to language or status of publication. Date of most recent searches: February 2007.

SELECTION CRITERIA

Trials were selected if they met the following criteria: design - randomised and controlled clinical trials; participants - children or adolescents (age < 16 years) or both receiving orthodontic treatment to correct prominent upper front teeth; interventions - active: any orthodontic brace or head-brace, control: no or delayed treatment or another active intervention; primary outcomes - prominence of the upper front teeth, relationship between upper and lower jaws; secondary outcomes: self esteem, any injury to the upper front teeth, jaw joint problems, patient satisfaction, number of attendances required to complete treatment.

DATA COLLECTION AND ANALYSIS

Information regarding methods, participants, interventions, outcome measures and results were extracted independently and in duplicate by two review authors. The Cochrane Oral Health Group's statistical guidelines were followed and mean differences were calculated using random-effects models. Potential sources of heterogeneity were examined.

MAIN RESULTS

The search strategy identified 185 titles and abstracts. From this we obtained 105 full reports for the review. Eight trials, based on data from 592 patients who presented with Class II Division 1 malocclusion, were included in the review.Early treatment comparisons: Three trials, involving 432 participants, compared early treatment with a functional appliance with no treatment. There was a significant difference in final overjet of the treatment group compared with the control group of -4.04 mm (95% CI -7.47 to -0.6, chi squared 117.02, 2 df, P < 0.00001, I(2) = 98.3%). There was a significant difference in ANB (-1.35 mm; 95% CI -2.57 to -0.14, chi squared 9.17, 2 df, P = 0.01, I(2) = 78.2%) and change in ANB (-0.55; 95% CI -0.92 to -0.18, chi squared 5.71, 1 df, P = 0.06, I(2) = 65.0%) between the treatment and control groups. The comparison of the effect of treatment with headgear versus untreated control revealed that there was a small but significant effect of headgear treatment on overjet of -1.07 (95% CI -1.63 to -0.51, chi squared 0.05, 1 df, P = 0.82, I(2) = 0%). Similarly, headgear resulted in a significant reduction in final ANB of -0.72 (95% CI -1.18 to -0.27, chi squared 0.34, 1 df, P = 0.56, I(2) = 0%). No significant differences, with respect to final overjet, ANB, or ANB change, were found between the effects of early treatment with headgear and the functional appliances. Adolescent treatment (Phase II): At the end of all treatment we found that there were no significant differences in overjet, final ANB or PAR score between the children who had a course of early treatment, with headgear or a functional appliance, and those who had not received early treatment. Similarly, there were no significant differences in overjet, final ANB or PAR score between children who had received a course of early treatment with headgear or a functional appliance. One trial found a significant reduction in overjet (-5.22 mm; 95% CI -6.51 to -3.93) and ANB (-2.27 degrees; 95% CI -3.22 to -1.31, chi squared 1.9, 1 df, P = 0.17, I(2) = 47.3%) for adolescents receiving one-phase treatment with a functional appliance versus an untreated control.A statistically significant reduction of ANB (-0.68 degrees; 95% CI -1.32 to -0.04, chi squared 0.56, 1 df, P = 0.46, I(2) = 0%) with the Twin Block appliance when compared to other functional appliances. However, there was no significant effect of the type of appliance on the final overjet.

AUTHORS' CONCLUSIONS

The evidence suggests that providing early orthodontic treatment for children with prominent upper front teeth is no more effective than providing one course of orthodontic treatment when the child is in early adolescence.

Kinesiographic and sonographic changes in young Class II patients treated with functional appliances

INTRODUCTION

The aim of this prospective, longitudinal, case-series study was to analyze the effect of orthodontic treatment by means of an activator appliance on the temporomandibular joint disc-condyle complex.

METHODS

The sample included 27 consecutively treated subjects with Class II Division 1 malocclussions (21 boys, 6 girls) who underwent orthodontic therapy with activators. The average pretreatment age was 11 years 2 months. Before treatment, all subjects were free of signs and clinical symptoms of temporomandibular joint disorders. The average treatment time with the activator appliance was 366 days; then all patients had Class I dental relationships. Kinesiographic and sonographic records before and after orthodontic treatment with the activator appliance were used to evaluate the disc-condyle complex. Univariate statistics were used in these outcome measurements to evaluate differences before and after treatment.

RESULTS

After treatment, the maximum opening increased significantly (4.81 mm), but the lateral and protrusive excursions did not change. The sonographic study showed no differences in temporomandibular joint sounds before and after treatment.

CONCLUSIONS

These results suggest that orthodontic treatment with an activator in a child without signs and clinical symptoms of temporomandibular joint disorders before treatment is not a risk factor for the development of temporomandibular pathology or mandibular dysfunction.

Herbst appliance therapy and temporomandibular joint disc position: A prospective longitudinal magnetic resonance imaging study

INTRODUCTION

The objective of this prospective study was to verify changes in the position of the temporomandibular joint (TMJ) disc by means of magnetic resonance images (MRIs) in adolescent patients treated with the Herbst appliance.

METHODS

Twenty consecutive Class II Division 1 patients treated with Herbst appliances were selected for the study. MRIs were analyzed at 3 stages: immediately before Herbst treatment (T1), 8 to 10 weeks after appliance placement (T2), and at the end of the 12-month Herbst treatment, immediately after appliance removal (T3).

RESULTS

Class I or overcorrected Class I dental-arch relationships were observed after Herbst therapy. The qualitative evaluation showed that each patient had the disc within normal limits at T1. At T2, a slight tendency toward disc retrusion because of mandibular advancement was observed, but, at T3, the disc returned to normal, similar to T1 values. By using a quantitative evaluation, parasagittal MRIs (central, medial, and lateral slices) of the TMJs showed that there was no change of disc position from T1 to T3, except in the central slice, which had a retrusive position of the articular disc at T3.

CONCLUSIONS

During the 12-month period of Herbst appliance treatment, mild changes in the position of the disc occurred in patients whose articular discs were within normal limits at T1. These changes were within normal physiological limits when evaluated in the short term.

Fränkel appliance therapy and the temporomandibular disc: a prospective magnetic resonance imaging study

This prospective clinical study assessed the effect of the Fränkel Functional Regulator-II (FR-II) treatment on the position and shape of the articular disc of the temporomandibular joint. The sample included magnetic resonance images of 112 temporomandibular joints taken initially (T1) and after 18 +/- 1 months (T2). The subjects were 56 white Brazilian children who were beginning their pubertal growth spurt. They had Class II Division 1 malocclusions and were selected from 800 children in neighborhood schools. They were randomly dichotomized into either the treated group (treated with the FR-II for 18 months) or the control group (not treated during the observation period). Our findings showed a low prevalence (3.57%) of disc displacement in the 112 temporomandibular joints. Mandibular propulsion with the FR-II had no unfavorable effect on the temporomandibular joints of the treated group; 100% of the patients kept an upper and interposed disc position (closed and open mouth, respectively) at T1 and T2. The control group had 7.1% partial anterior medial disc displacement, both at T1 and T2. Regarding disc morphology, the control group showed biconcave-shaped discs in 82.1% of the joints, statistically similar to the treated group (89.3%) at the beginning of the observation period. At T2, the articular disc morphology of the control group was unchanged, but that of the treated group was significantly more normal (P =.016), progressing from nonbiconcave at T1 (10.7%) to biconcave at T2 (100%). Our results showed that disc displacement is not a complication of functional appliance therapy; in fact, such treatment might help some children with incipient temporomandibular disorders.