"Effective condylar growth" and chin position changes in Herbst treatment: a cephalometric roentgenographic long-term study

Comparison of the Effects of Fixed and Removable Functional Orthodontic Treatment on the Mandibular Trabecular Bone in Fractal Analysis

Objective

The aim of this retrospective study was to compare the effects of the Twin block and Herbst appliances on the mandibular trabecular pattern using fractal dimension analysis (FDA) of panoramic radiographs (PRs).

Methods

The PRs of 50 subjects with skeletal Class II malocclusion who underwent the Twin block (T-group, average age: 11.63±0.87; 25 girls, 25 boys), 50 subjects with skeletal Class II malocclusion who underwent the Herbst (H-group, average age: 11.72±0.91; 27 girls, 23 boys), and 50 controls (C-group average age: 11.67±0.83; 24 girls, 26 boys) were selected. The condyle, corpus, and angulus regions of all groups in the mandible were examined using FDA.

Results

The condylar region (p≤0.001) and corpus mandible in the treatment groups (T-group: right, p≤0.05, left, p≤0.01; H-group: p≤0.05), as well as the left and right condylar region (p≤0.001) and left corpus mandible (p≤0.05) in the C-group, all indicated substantial increases in FDA between T0 and T1. Inter-group comparisons indicated that the T-group had greater variances in the condyle (p≤0.001) compared to the H group.

Conclusion

As the findings revealed both Twin block and Herbst appliances not only contributed to the dentoalveolar structure but also provided remodeling of the mandibular trabecular structure. Consequently, the null hypothesis was rejected.

A Three-Dimensional Evaluation of Skeletal and Dentoalveolar Changes in Growing Class II Patients after Functional Appliance Therapy: A Retrospective Case-Control Study

Background: The aim was to assess three-dimensionally mandibular and maxillary changes in growing Class II patients treated with removable functional appliances followed by fixed appliances. Methods: Twenty-four Class II patients (age range: 9 to 14, mean: 12.1 ± 1.1 years) treated with removable functional appliances followed by fixed appliances (functional appliance group-FAG) were retrospectively selected and compared to an age-matched control group (CG) treated with fixed appliances only. To be included in the study, pre- and post-treatment CBCT scans had to be available. The CBCTs were used to analyze, in 3D, the changes following treatment and growth. Results: Before treatment, overjet (FAG: 9 mm ± 2.8 (mean ± standard deviation); CG: 4 mm ± 1.7), ANB (FAG: 5.7° ± 2.0; CG: 3.2° ± 1.4), and effective mandibular length (FAG: 113.0 mm ± 4.1; CG: 116.6 mm ± 5.9) were statistically significantly different between the two groups. After treatment, overjet (FAG: -6.8 mm ± 2.8; CG: -1.8 mm ± 1.8) and effective mandibular length (FAG: 6.3 mm ± 2.6; CG: 3.9 mm ± 2.6) statistically significantly changed. There was a significant difference in the treatment effect between the FAG and the CG in overjet, ANB, and effective mandibular length. Conclusions: The results indicate that functional appliances are effective in correcting Class II malocclusions. The growth modification in the FAG resulted in an increase in mandibular length. Yet, the final length of the mandible in the FAG was smaller when compared to the CG.

Wnt/β-catenin signaling pathway is activated in the progress of mandibular condylar cartilage degeneration and subchondral bone loss induced by overloaded functional orthopedic force (OFOF)

Objective

To explore the role of Wnt/β-catenin signaling pathway in the pathogenesis and progression of temporomandibular joint osteoarthritis (TMJ OA) caused by overloaded force.

Materials and methods

We generated a rat model of forward mandibular extension device to induce TMJ OA by overloaded force. Condylar cartilage samples were collected at 2wk, 4wk, and 8wk after appliances were installed. Changes of the condylar cartilage and subchondral bone were evaluated by hematoxylin and eosin (HE), Safranin O and Fast Green staining (SO&FG), micro-CT, tartrate resistant acid phosphatase (TRAP) staining. The expression levels of β-catenin, COL-2, MMP3 and sclerostin (SOST) were detected by immunohistochemistry (IHC) and PCR.

Results

HE, SO&FG, micro-CT, OARSI and Mankin scores showed that the condyle cartilage layer was significantly thinner and proteoglycan loss in the overloded group. TRAP staining exhibited that the number of positive osteoclasts increased and OPG level decreased in the overload group. IHC, PCR showed that the expression of COL2 and SOST decreased, while MMP3 and β-catenin increased in the overload group.

Conclusion

Wnt/β-catenin signaling pathway is activated in the progress of mandibular condylar cartilage degeneration and subchondral bone loss induced by overloaded functional orthopedic force (OFOF)

Comparative assessment of the cell-surface antigens and gene expression profiles of the gingival tissue biomarkers in subjects with fixed functional and removable functional orthodontic appliances

BACKGROUND

This study aimed to examine the cellular components of the gingiva during orthodontic treatment with fixed and removable appliances. The cellular and molecular cues of pathologies of the gingival tissue associated with the use of different orthodontic appliances could be studied.

MATERIALS AND METHODS

Tissue samples of gingiva were received from healthy patients undergoing gingivectomy for aesthetic purpose and from patients with fixed and removable functional orthodontic appliances undergoing gingivectomy for gingival overgrowth. The collected samples were stored in a sterile container with phosphate-buffered saline and to carry out further processes it was transported to the laboratory.

RESULTS

Cells positive for ECAD and NCAD were found to be increased in fixed appliances where as CD90 and CD105 positive cells showed no significant difference in all the three groups. CD24 and CD146 positive cells were increased significantly in removable and fixed than normal whereas CD133 positive cells were decreased in removable and fixed than normal. CD44 positive cells showed no noticeable change in all three groups. The gene expression levels of KRT5, SOX2, NANOG, and CXCL5 were found to be significantly increased in removable and fixed appliance groups. However, KRT8, CXCL10, and TIMP1 were increased only in fixed appliance group but CXCL10 showed decreased expression in removable appliance group. KRT6A, MYC, and MMP9 were decreased in fixed appliance group whereas MYC and MMP9 were increased in removable appliance group. KRT6A, KRT8, and TIMP1 showed no significant difference in removable appliance group.

CONCLUSION

This study demonstrated essential roles of various genes, showing their contribution in regulating cell proliferation and migration in both the removable and fixed functional appliances.

Management of Asymmetric Mandibular Retrognathia with Differential Loading Technique: A Case Report

Class II malocclusion cases possess a constant challenge to orthodontists since time immemorial. Mandibular retrusion is the most common feature of class II malocclusion, rather than maxillary prognathism. Association of class II with asymmetry, a condition called asymmetric mandibular retrognathia (AMR), gives a tougher challenge to orthodontists for management. The following case presents effective management of AMR using differential loading technique. A young boy aged 12 years presented with mandibular retrognathia associated with facial asymmetry. He was treated with a differential force loading technique using a fixed functional appliance.

Steering the Mandible in the Right Direction : Forsus Case Series

We are in the process of discovery of new vistas for technological advances in terms of various appliances with a vision of making orthodontic treatment compliance free as well as successful. Due to improved technology, the enigma of treating the Class II syndrome is palliated. “Out of the box” thinking has become a norm to treat certain situations that were not corrected in noncompliant patients. Fixed functional appliances are valuable tools introduced to assist the correction of skeletal Class II malocclusion with mandibular retrognathia at the deceleration stage of growth for achieving stable results. In this direction a case series is reported of patients having the above conditions and undergoing orthodontic treatment using a Forsus FFA. Joining hands with technology is a win-win situation for both the patient and the orthodontist.

Treatment and posttreatment effects of Herbst appliance therapy on trabecular structure of the mandible using fractal dimension analysis

OBJECTIVES

This controlled study aimed to evaluate the effects of Herbst therapy on the trabecular structure of the condyle and angulus mandible using fractal dimension analysis (FD-A) accompanied by skeletal cephalometric changes.

MATERIAL AND METHOD

The panoramic and cephalometric radiographs of 30 patients with skeletal Class II malocclusion treated with the Herbst appliance (C II-H group, mean age: 15.23 ± 1.08), 30 patients with skeletal Class II malocclusion that received fixed orthodontic treatment (C II-C group, mean age: 15.73 ± 1.38), and 30 patients with skeletal Class I malocclusion (C I-C group, mean age: 15.90 ± 1.30) were selected. FD-A was performed on the superoposterior region (C-SP) and centre of the condyles (C-C) and the mandibular angulus (Ang) on the panoramic radiographs taken at the pretreatment (T0), intermediate stage of treatment (T1), and posttreatment (T2) timepoints just like cephalometric analysis.

RESULTS

Herbst therapy provided a statistically significant increase in SNB, ANS-Me, Na-Me, S-Go, Co-Gn and a decrease in ANB and overjet (P < 0.05). All skeletal changes remained stable during the fixed appliance treatment after Herbst. The FD values in C-C increased (P < 0.05), and C-SP values decreased (P < 0.05) during Herbst therapy, while after removal of the Herbst appliance, no significant change was observed despite an increase in C-SP. The Ang value did not change during Herbst treatment, but then increased significantly (P < 0.05). There was no significant change in the FD values of the C I-C and C II-C groups at any stage of treatment. The C-C and C-SP changes at T1-T0 period, C-SP and Ang changes at T2-T1 period, and C-C, C-SP, and Ang values at T2-T0 period were found higher in C II-H group compared with the C II-C group significantly (P < 0.05).

CONCLUSION

Herbst therapy changed the trabecular structure of the condyles in different directions at the superoposterior and central regions of the condyles, while the structural complexity of the angulus mandible, which did not change during the Herbst treatment, increased during the fixed orthodontic treatment after Herbst.

Three-dimensional condylar changes from Herbst appliance and multibracket treatment: A comparison with matched Class II elastics

INTRODUCTION

The purpose of this study was to quantify and qualify the 3-dimensional (3D) condylar changes using mandibular 3D regional superimposition techniques in adolescent patients with Class II Division 1 malocclusions treated with either a 2-phase or single-phase approach.

METHODS

Twenty patients with Herbst appliances who met the inclusion criteria and had cone-beam computed tomography (CBCT) images taken before, 8 weeks after Herbst removal, and after the completion of multibracket appliance treatment constituted the Herbst group. They were compared with 11 subjects with Class II malocclusion who were treated with elastics and multibracket appliances and who had CBCT images taken before and after treatment. Three-dimensional models generated from the CBCT images were registered on the mandible using 3D voxel-based superimposition techniques and analyzed using semitransparent overlays and point-to-point measurements.

RESULTS

The magnitude of lateral condylar growth during the orthodontic phase (T2-T3) was greater than that during the orthopedic phase (T1-T2) for all condylar fiducials with the exception of the superior condyle (P <0.05). Conversely, posterior condylar growth was greater during the orthopedic phase than the subsequent orthodontic phase for all condylar fiducials (P <0.05). The magnitude of vertical condylar development was similar during both the orthopedic (T1-T2) and orthodontic phases (T2-T3) across all condylar fiducials (P <0.05). Posterior condylar growth during the orthodontic phase (T2-T3) of the 2-phase approach decreased for all condylar fiducials with the exception of the posterior condylar fiducial (P <0.05) when compared with the single-phase approach.

CONCLUSIONS

Two-phase treatment using a Herbst appliance accelerates condylar growth when compared with a single-phase regime with Class II elastics. Whereas the posterior condylar growth manifested primarily during the orthopedic phase, the vertical condylar gains occurred in equal magnitude throughout both phases of the 2-phase treatment regime.

Evaluation of Profile Changes in Class II Individuals Treated by Means of Herbst Miniscope Appliance

Background: To evaluate the profile changes following orthopedic/orthodontic treatment with the Herbst Miniscope^® appliance in subjects affected with Class II malocclusion with mandibular retrusion. Methods: A total of 44 patients presenting a skeletal Angle Class II malocclusion (ANB > 4°) due to mandibular retrusion and a cervical maturation stage between CS2 and CS3 were included in the study. Of these 44 patients, 22 (mean age 11.9 ± 1.3, HBT group) were treated using the Herbst appliance, while 22 (mean age 10.6 ± 1.3, CTR group) were followed for a 12-month observational period. A cephalometric tracing was performed at the beginning of treatment (T0) and after 12 months (T1). Results: In both groups there was a significant advancement of soft tissue pogonion (HBT = 3.5 ± 3.0 mm, p < 0.001; CTR = 2.2 ± 2.9 mm, p < 0.001), but the difference between the two groups was not significant (p = 0.172). On the contrary, both groups had a significant advancement of the mandibular sulcus (HBT = 3.7 ± 2.8 mm, p < 0.001; CTR = 1.2 ± 2.2 mm, p < 0.001) and a lower lip protrusion (HBT = 3.45 ± 2.51 mm, p < 0.001; CTR = 1.7 ± 2.7 mm, p = 0.008), but in both cases the HBT group showed a statistically significant greater increase in sulcus protrusion (p = 0.002) and lower lip protrusion (p = 0.029) than controls. There were no statistically significant effects on the upper jaw. Conclusions: The Herbst appliance advanced the lower jaw soft tissues.

Long-term dentoskeletal changes of class II growing patients' treatment with the propulseur universal light appliance. A prospective controlled study

BACKGROUND

Class II is one of the most common malocclusions. The prevailing aspect in Class II patients is a mandibular deficiency. Various removable and fixed functional therapies are used in order to enhance the mandibular growth or position. The aim of this prospectively controlled study was to evaluate long-term dentoskeletal changes obtained by a functional appliance for Class II.

METHODS

Prospective controlled study, based on a sample size calculation. 26 Class II Division 1 patients (11.8±1.5 years) were consecutively treated with the propulseur universal light (PUL) appliance and a multi bracket appliance (PG), they were compared to a sample of 26 Class II untreated patients (11.5±0.8 years) (CG). Lateral cephalograms were taken before and after the PUL therapy, and after multibracket treatment. Interaction analysis was carried out to test whether the PUL parameters in treatment groups were different according to the acquisition times, using the Linear Mixed-Effects Model.

RESULTS

Significant ANB, Overjet and WITS differences existed in treatment groups according to the time. In particular, comparing to T1 vs. T0, the relative difference (RD) means in the control group were -0.34, -0.31 and 0.17 for ANB, Overjet and WITS, respectively. The corresponding RD means in the treated group PG were -1.58, -4.27 and -2.38. Comparing to T2 vs. T0, the RD means in the control group were -0.36, -0.51 and 0.63 for ANB, Overjet and WITS, respectively. While the corresponding RD means in the treated group were -2.08, -5.12 and -2.50.

CONCLUSIONS

The PUL appliance successfully corrected class II malocclusion. The long term correction was mainly due to dentoalveolar effects: therapy success was 91% for overjet correction and 76% for ANB correction. During the post functional appliance period, overjet was stable in 77% of the treated subjects, and ANB in 74% of the treated subjects.

Reliability and accuracy of segmentation of mandibular condyles from different three-dimensional imaging modalities: a systematic review

OBJECTIVE

To critically synthesize the literature surrounding segmentation of the mandibular condyle using three-dimensional imaging modalities. Specifically, analyzing the reliability and accuracy of methods used for three-dimensional condyle segmentation.

METHODS

Three electronic databases were searched for studies reporting the reliability and accuracy of various methods used to segment mandibular condyles from three-dimensional imaging modalities. Two authors independently reviewed articles for eligibility and data extraction.

RESULTS

Nine studies fulfilled the inclusion criteria. Eight studies assessed the condylar segmentation from CBCT images and limited studies were available on non-CBCT three-dimensional imaging modalities. Threshold-based volume segmentation, manual segmentation, and semi-automatic segmentation techniques were presented. Threshold-based volume segmentation reported higher accuracy when completed by an experienced technician compared to clinicians. Adequate reliability and accuracy were observed in manual segmentation. Although adequate reliability was reported in semi-automatic segmentation, data on its accuracy were lacking.

CONCLUSION

A definitive conclusion with regards to which current technique is most reliable and accurate to efficiently segment the mandibular condyle cannot be made with the currently available evidence. This is especially true in terms of non-CBCT imaging modalities with very limited literature available.

Condyle-glenoid fossa relationship after Herbst appliance treatment during two stages of craniofacial skeletal maturation: A retrospective study

OBJECTIVES

To perform a three-dimensional evaluation of the position of the condyles in patients treated with Herbst appliance (HA) in two stages of cervical vertebral maturation.

SETTING AND SAMPLE POPULATION

Retrospective case-control study. Pubertal Herbst group (PHG; n = 24, mean age 14.5 years, CS 3 and CS 4) and pre-pubertal Herbst group (PPHG; n = 17, mean age 9.9 years, CS 1 and CS 2) were contrasted with comparison groups of non-orthopaedically treated Class II patients in pubertal (PCG; n = 17, mean age 13.9 years) and pre-pubertal maturational stages (PPCG; n = 18, mean age 10.6 years).

MATERIALS AND METHODS

Cone-beam computer tomography scans were taken before treatment (T0) and at T1 after 8 to 12 months. Point-to-point measurements of the displacement of the condyles between T0 and T1, relative to the glenoid fossae, were performed in the X, Y, Z and 3D perspectives. Qualitative assessments using semi-transparent overlays and colour mapping also were produced.

RESULTS

The displacement of the condyles within the glenoid fossae in the treated groups was small (<0.75 mm; P > .05). Relative to the glenoid fossa, condylar position at T1 was similar to T0 in pre-pubertal and pubertal groups (P > .05). Similar condylar rotations from T0 to T1 were observed in Herbst and comparison groups, and no significant difference was found between pre-pubertal and pubertal patients.

CONCLUSIONS

Regardless the stage of skeletal maturation, HA treatment did not change the condyle-glenoid fossa relationship.

Histological Alterations from Condyle Repositioning with Functional Appliances in Rats

OBJECTIVE

This study was designed to assess the morphological and histological alterations of the condyle of rats undergoing forward mandibular repositioning via functional appliance.

MATERIALS AND METHODS

Functional appliances were mounted onto the upper jaws of rats. Morphological analysis was conducted on micro-CT images of sacrificed animals. Histological changes in condyle were examined by immunohistochemistry using proliferating cell nuclear antigen (PCNA), matrix metalloproteases (MMPs), vascular endothelial growth factor (VEGF), tissue inhibitors of matrix metalloproteinases (TIMP-1), interleukin 1b (IL-1β), Aggrecan and Type II collagen. Osteoclast activity was identified by tartrate-resistant acid phosphatase (TRAP) staining.

RESULTS

Morphological analysis confirmed the forward positioning of the condyles of rats by the appliance, but the position gradually returned to normal on days 14 after treatment. An increase in PCNA positive cells was observed in the posterior region of the condyles on days 7, whereas PCNA positive cells decreased in the anterior region. Aggrecan and Type II collagen localization increased in the posterior region throughout the entire period, but decreased in the anterior region on days 14. In both regions, IL-1β and VEGF localization was significantly increased for 14 days while MMPs localization was evident throughout the entire period. The TRAP positive cells were significantly elevated on days 3 and 7.

CONCLUSIONS

These results suggest that the functional appliance therapy induces significant morphological and histological changes in the anterior and posterior regions of the condyle and subsequently causes adaptive cellular functions such as chondrocyte differentiation and cartilage matrix formation.

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.

Three-dimensional skeletal mandibular changes associated with Herbst appliance treatment

OBJECTIVES

Three-dimensional evaluation of skeletal mandibular changes following Herbst appliance treatment.

SETTING AND SAMPLE POPULATION

Retrospective case-control study, based on a sample size calculation. Twenty-five pubertal patients treated with Herbst appliance (HAG), and 25 matched Class II patients who received other non-orthopaedic dental treatments (CG).

MATERIAL AND METHODS

Three-dimensional models were generated from pre-treatment (T0) and post-treatment (T1) cone beam computed tomograms. Volumetric registration on the cranial base was used to assess mandibular displacement; volumetric regional registration was performed to evaluate mandibular growth. Quantitative measurements of X, Y, Z and 3D Euclidian changes, and also qualitative visualization by colour-mapping and semi-transparent overlays were obtained.

RESULTS

Downward displacement of the mandible was observed in both HAG and CG (2.4 mm and 1.5 mm, respectively). Significant forward displacement of the mandible was observed in the HAG (1.7 mm). HAG showed greater 3D superior and posterior condylar growth than the CG (3.5 mm and 2.0 mm, respectively). Greater posterior growth of the ramus was noted in the HAG than in CG.

CONCLUSIONS

Immediately after Herbst therapy, a significant mandibular forward displacement was achieved, due to increased bone remodelling of the condyles and rami compared to a comparison group. Three-dimensional changes in the direction and magnitude of condylar growth were observed in Herbst patients.

Mandibular fossa morphology during therapy with a fixed functional orthodontic appliance : A magnetic resonance imaging study

OBJECTIVE

During therapy of distoclusion entailing a rigid, fixed orthodontic appliance, the mandibular fossa and condyle are ideally remodeled, while dentoalveolar effects occur through adaptive mechanisms. Adaptive processes, especially in the fossa region, have not been adequately investigated. Our magnetic resonance imaging (MRI) investigation aimed to assess the effects of therapy with a functional mandibular advancer (FMA) on mandibular fossa morphology.

PATIENTS AND METHODS

We monitored via MRI the therapeutic course of 25 patients at three time points. Visual findings and metric assessments were carried out in the sagittal plane. Three-dimensional (3D) reconstructions of the joint structure of two exemplary patients were also made.

RESULTS

Visual examinations of the MRI slices at the three time points revealed no changes in fossa shape in any of the 50 temporomandibular joints. Lateral comparisons showed that the morphology of the fossae of all 25 patients was identical. Metric analysis demonstrated no significant alterations in width, depth, or in their ratio, not even laterally. Nine measurements of the distances between the porion, mandibular fossa, and articular eminence revealed no significant changes in total or on the left and right sides, or intralaterally.

CONCLUSION

The visual findings and metric analyses of parasagittal MRI slices did not indicate any morphological changes in the mandibular fossa or articular eminence in patients with distoclusion treated via a rigid, fixed orthodontic appliance. However, special reworking of the MRI data facilitated reconstruction of the surfaces of joint structures in 3D. This new method makes it possible to depict more accurately and noninvasively the adaptive mechanisms not ascertainable via metric methods and to assess them as 3D structures.

Treatment changes of hypo- and hyperdivergent Class II Herbst patients

OBJECTIVES

To determine the relative effects of Herbst appliance therapy in hypo- and hyperdivergent patients.

MATERIALS AND METHODS

The treated group included 45 growing Class II, division 1, patients treated with stainless steel crown Herbst appliances, followed by fixed edgewise appliances. The untreated control group consisted of 45 Class II, division 1, subjects, matched to the treated sample based on Angle classification, age, sex, and pretreatment mandibular plane angle (MPA). Subjects were categorized as hypo- or hyperdivergent based on their MPAs. Pre- and posttreatment cephalograms were traced and superimposed on cranial base and mandibular structures.

RESULTS

The primary effect of the Herbst in terms of maxillomandibular correction was in the maxilla. It significantly restricted maxillary growth, producing a "headgear effect." Mandibular treatment changes depended on divergence. Hyperdivergent patients experienced a deleterious backward true mandibular rotation with Herbst treatment. Hypodivergent patients, as well as untreated hypo- and hyperdivergent controls, underwent forward true mandibular rotation. However, hypodivergent chins did not advance any more than expected for untreated hypodivergent Class II patients.

CONCLUSIONS

Hypo- and hyperdivergent patients benefit from the Herbst's headgear effect. While the mandibular growth of hypodivergent patients overcomes the negative rotational effects, hyperdivergent patients undergo a deleterious backward mandibular rotation and increases in facial height.

Fixed-functional appliance treatment combined with growth hormone therapy

The purpose of this study was to illustrate the effects of growth hormone (GH) therapy and fixed functional appliance treatment in a 13-year-old Class II malocclusion patient without GH deficiency. GH has been shown to effectively increase endochondral growth and induce a more prognathic skeletal pattern. Although a major concern in Class II retrognathic patients is chin deficiency, long-term studies have shown that the mandibular growth enhancement effects of functional appliances are clinically insignificant. This case report demonstrates that the mandible grew significantly during fixed functional appliance treatment combined with GH therapy, with stable results during 2 years 11 months of retention. More studies are needed to evaluate GH therapy as a supplement in Class II treatment.

PowerScope a Class II corrector - A case report

Managing mild to moderate Class II malocclusion is a one of the common and major challenges to orthodontists. Class II discrepancies with mandibular deficiency during active growth are usually treated by myofunctional appliances. Fixed functional appliances evolved due to the noncompliance with conventional myofunctional appliances. This case report illustrates the efficiency of PowerScope in correction of skeletal Class II with mandibular deficiency in a patient aged 13 years who has reported to the department with a chief complaint of forwardly placed upper front teeth. This case with functional jaw retrusion was treated initially with MBT 0.022” prescription followed by PowerScope. Pre-, mid- and post-treatment cephalograms were obtained, and cephalometric analysis was performed. Stable and successful results were obtained with a substantial improvement in facial profile, skeletal jaw relationship, and overall esthetic appearance of the patient. A significant forward displacement of the mandible was the principal element for successful correction of Class II malocclusion. PowerScope provides the best results for Class II management, thus enables us to treat such cases by a nonextraction approach rather than contemplating extractions.

Displacement of the Mandibular Condyles Immediately after Herbst Appliance Insertion - 3D Assessment

OBJECTIVE

To test the following two hypotheses regarding the consequences of Herbst appliance (HA) insertion: 1) a significant clockwise mandibular rotation will occur and 2) the displacement of the condyles will follow the same magnitude of the changes of overjet (OJ) and overbite (OB).

METHODS

Virtual 3D surface models of 25 patients were generated from cone-beam computed tomographs taken before treatment and immediately after HA insertion. Scans were registered on the cranial base and were analyzed using point-to-point measurements, color-coded maps, and semitransparent overlays. Statistical tests included correlation and simple regression analysis.

RESULTS

Pitch rotation, ranging from -2.2° to 2.2° (mean, 0.2°), was observed in clockwise and counterclockwise directions. Condylar sagittal displacement presented a positive correlation with OJ changes. Each millimeter of OJ correction resulted in an anterior condylar displacement of approximately 0.95 mm. Vertical condylar displacement correlated with OB changes and varied mostly between 2 mm and 4.5 mm.

CONCLUSION

Immediately after HA insertion, no significant clockwise mandibular rotation was observed. The condyles were displaced anteriorly and inferiorly. Condylar anterior displacement and OJ correction presented a ratio close to 1:1. The vertical displacement of the condyles did not follow the same magnitude of OB changes.

Volumetric changes in pharyngeal airway in Class II division 1 patients treated with Forsus-fixed functional appliance: A three-dimensional cone-beam computed tomography study

Objective:

Recent years have witnessed a renewed interest to determine a quantifiable relationship between mandibular advancement performed with an orthodontic appliance and the resulting airway volume. The study was conducted to evaluate the volumetric changes in pharyngeal airway space using cone-beam computed tomography (CBCT) in Class II division 1 patients with retrognathic mandible treated by Forsus-fixed functional appliance and to compare them with their pretreatment findings.

Materials and Methods:

Thirty patients with Class II division 1 malocclusion of age group 10–17 years were selected randomly and evaluated for changes in pharyngeal airway volume with and without Forsus-fixed functional appliance. Patients in each group underwent CBCT scan of head and neck region at pretreatment stage and 6 months after the initial scan. Institutional approval for the project was obtained from the Ethical Committee. Volumetric changes of upper (oropharynx) and lower (hypopharynx) pharyngeal airways were measured on scanogram using computer software and intragroup comparisons were done.

Results:

There was a statistically significant increase in the volume of both hypopharynx and oropharynx and also total airway volume in patients treated with Forsus-fixed functional appliance. Three-dimensional reconstruction of the airway also demonstrates a considerable increase in pharyngeal airway space.

Conclusion:

Forsus-fixed functional appliance can be a promising appliance for improving pharyngeal airway volume in Class II division 1 patients with retrognathic mandible thus preventing obstructive sleep apnea and other respiratory problems in future. However, the long-term implications of this treatment modality need further consideration and a longer period of follow-up.

Stability of Class II fixed functional appliance therapy--a systematic review and meta-analysis

OBJECTIVES

To systematically search for scientific evidence concerning the stability of treatment (Tx) results achieved by means of Class II fixed functional appliance therapy and to assess possible differences between appliances.

SEARCH METHODS

An electronic search of databases and orthodontic journals was carried out (until December 2013), with supplemental hand searching. In addition to the names of all identified appliances, the term fixed functional was used in combination with each of the following search terms: long-term, post-Tx, relapse, retention, stability.

SELECTION CRITERIA

To be included in the review, the articles had to contain clear data on: Class II Tx with a fixed functional appliance (>5 patients), post-Tx period ≥ 1 year, assessment of ANB angle, Wits appraisal, molar relationship, soft-tissue profile convexity excluding the nose, overjet and/or overbite.

DATA COLLECTION AND ANALYSIS

The literature search revealed 20 scientific investigations which corresponded to only two of the 76 identified appliances (Herbst and Twin Force Bite Corrector). As only one publication was found for the Twin Force Bite Corrector, a meta-analysis could only be performed for Herbst Tx. The data were extracted, pooled and weighted according to the number of patients in each study.

RESULTS

The mean values for post-Tx relapse (percentages relative to the Tx changes) were: ANB angle 0.2 degrees (12.4 per cent), Wits appraisal 0.5mm (19.5 per cent), sagittal molar relationship 1.2mm/0.1 cusp widths (21.8 per cent /6.5 per cent); soft-tissue profile convexity excluding nose less than 0.1 degrees (1.0 per cent), overjet 1.8mm (26.2 per cent), overbite Class II:1 1.4mm (44.7 per cent), overbite Class II:2 1.0mm (22.2 per cent).

CONCLUSIONS

The scientific evidence concerning the stability of Tx results is inexistent for most fixed functional appliances for Class II correction except for Herbst appliance Tx. Even if the evidence level of most included studies is rather low, good dentoskeletal stability without clinically relevant changes was found for most variables.

Dental and skeletal changes in patients with mandibular retrognathism following treatment with Herbst and pre-adjusted fixed appliance

Objective

To assess the dentoskeletal changes observed in treatment of Class II, division 1 malocclusion patients with mandibular retrognathism. Treatment was performed with the Herbst orthopedic appliance during 13 months (phase I) and pre-adjusted orthodontic fixed appliance (phase II).

Methods

Lateral cephalograms of 17 adolescents were taken in phase I onset (T₁) and completion (T₂); in the first thirteen months of phase II (T₃) and in phase II completion (T₄). Differences among the cephalometric variables were statistically analyzed (Bonferroni variance and multiple comparisons).

Results

From T₁ to T₄, 42% of overall maxillary growth was observed between T₁ and T₂ (P < 0.01), 40.3% between T₂ and T₃ (P < 0.05) and 17.7% between T₃ and T₄ (n.s.). As for overall mandibular movement, 48.2% was observed between T₁ and T₂ (P < 0.001) and 51.8% between T₂ and T₄ (P < 0.01) of which 15.1% was observed between T₂ and T₃ (n.s.) and 36.7% between T₃ and T₄ (P < 0.01). Class II molar relationship and overjet were properly corrected. The occlusal plane which rotated clockwise between T₁ and T₂, returned to its initial position between T₂ and T₃ remaining stable until T₄. The mandibular plane inclination did not change at any time during treatment.

Conclusion

Mandibular growth was significantly greater in comparison to maxillary, allowing sagittal maxillomandibular adjustment. The dentoalveolar changes (upper molar) that overcorrected the malocclusion in phase I, partially recurred in phase II, but did not hinder correction of the malocclusion. Facial type was preserved.

Treatment effects of removable functional appliances in patients with Class II malocclusion: a systematic review and meta-analysis

OBJECTIVE

To assess the treatment effects of removable functional appliances (RFAs) in treated versus untreated patients with Class II malocclusion by means of lateral cephalometric radiographs.

SEARCH METHODS

Unrestricted electronic search of 18 databases and manual searches up to October 2013.

SELECTION CRITERIA

Prospective randomized and non-randomized controlled trials reporting on cephalometric angular measurements of Class II patients treated with RFAs and their matched controls.

DATA COLLECTION AND ANALYSIS

Skeletal, dental, and soft tissue changes were annualized and stratified to short- and long-term effects. Methodological limitations were evaluated with the Cochrane Risk of Bias tool and the Downs and Black checklist. Mean differences (MDs) with their 95% confidence intervals (CIs) were calculated from random-effects meta-analyses. Patient- or appliance-related subgroup analyses and sensitivity analyses were performed with mixed-effects models.

RESULTS

Seventeen studies were included (1031 patients; mean age: 10.6 years), with most of them originating from university clinics and reporting short-term effects (directly after the removal of RFAs). Treatment was associated with minimal reduction of SNA angle (11 studies, MD = -0.28 degree/year, 95% CI: -0.44 to -0.12 degree/year), minimal increase of SNB angle (11 studies, MD = 0.62 degree/year, 95% CI: 0.36-0.88 degree/year), and small decrease of ANB angle (10 studies, MD = -1.14 degree/year, 95% CI: -1.52 to -0.77 degree/year) compared to untreated Class II patients. RFAs caused significant dentoalveolar changes (predominantly retroclination of the upper incisors) and significant soft tissue changes. Skeletal changes were more pronounced with the Twin Block appliance. Various patient- or appliance-related factors influenced the results of the subgroup analyses, while the sensitivity analyses indicated robustness. Existing evidence was inadequate to assess the long-term effectiveness of RFAs.

CONCLUSIONS

The short-term evidence indicates that RFAs are effective in improving Class II malocclusion, although their effects are mainly dentoalveolar, rather than skeletal.

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.

Stability of molar relationship after non-extraction Class II malocclusion treatment

OBJECTIVE

This study aimed to evaluate the stability of molar relationship after non-extraction treatment of Class II malocclusion.

METHODS

The sample comprised 39 subjects (16 females, 23 males) with initial Class II malocclusion treated with no extractions, using fixed appliances. Mean age at the beginning of treatment was 12.94 years, at the end of treatment was 15.14 years and at post-retention stage was 21.18 years. Mean treatment time was 2.19 years and mean time of post-treatment evaluation was 6.12 years. To verify the influence of the severity of initial Class II molar relationship in stability of molar relationship, the sample was divided into two groups, one presenting a ½-cusp or ¾-cusp Class II molar relationship, and the other with full-cusp Class II molar relationship. In dental casts from initial, final and post-retention stages, molar, first and second premolars and canine relationships were measured. Data obtained were analyzed by dependent ANOVA, Tukey and Pearson's correlation tests, as well as independent t test between the two groups divided by severity of initial molar relationship.

RESULTS

There was a non-statistically significant 0.12-mm relapse of molar relationship. The initial severity of Class II molar relationship was not correlated to relapse in the post-retention period. When compared, the two groups showed no difference in relapse of molar relationship.

CONCLUSIONS

It was concluded that correction of Class II molar relationship is stable and initial severity does not influence relapse of molar relationship.

Prediction of lower incisor proclination during Xbow treatment based on initial cephalometric variables

OBJECTIVE

To predict lower incisor proclination from initial cephalometric values in Class II division 1 patients treated in phase I with the Xbow appliance.

MATERIALS AND METHODS

Two hundred forty-nine mild to moderate Class II division 1 patients treated with the Xbow appliance as a phase I treatment were considered. Patients were in late mixed dentition or early permanent dentition. Commonly used cephalometric variables at T1 (before treatment) were used to predict lower incisor proclination after Xbow treatment (T2). A principal component analysis (PCA) was performed. The four extracted PCA components were skeletal component, incisal distance, anterior facial projection, and maxillo-mandibular relation. Thereafter, a multiple linear regression analysis (MLRA) was performed using the four extracted PCA components at T1 as predictor variables, and lower incisor inclination relative to the mandibular plane (L1-MP) at T2 as the dependent variable.

RESULTS

The mean L1-MP at T1 was 95.46 degrees and the mean L1-MP at T2 was 98.51 degrees, resulting in a mean difference of 3.04 degrees. Only incisal distance and maxillo-mandibular relation PCA components had significance (P < .05) according to the MLRA. The overall model gave an adjusted R2 value (coefficient of determination) of 0.091.

CONCLUSION

The best prediction model could account for only 9% of the total variability. Using common cephalometric variables at T1, average lower incisor proclination from Xbow treatment cannot be predicted in a clinically meaningful way.

Effectiveness of bionator therapy for Class II malocclusions: a comparative long-term study

OBJECTIVE

The goal of this retrospective study was to examine the effectiveness of isolated bionator therapy in Class II patients both longitudinally and over the long term. We aimed to determine whether skeletal and/or dentoalveolar reactions differ in relationship to the Angle Class (II, Division 1 vs. II, Division 2).

PATIENTS AND METHODS

A total of 50 juvenile patients with Class II malocclusion (♀ n = 26, ♂ n = 24) were included. A total of 24 patients presented an Angle Class II, Division 1 and 26 an Angle Class II, Division 2. We compared the patients' lateral cephalograms taken at the beginning of treatment (t1: 10.1 years), after active therapy (t2: 13.8 years), and at the end of retention (t3: 16.4 years) analyzing the following cephalometric parameters: SNA, SNB, ANB, ANB(ind), SNPog, Wits appraisal, U1-SN, U1-SpP, L1-MeGo, interincisal angle. Mean and standard deviations of each of the variables were calculated. Differences between t1-t2 and t2-t3 were tested for statistical significance. Changes in the variables were then analyzed biometrically for specific differences in terms of Angle Class (II, Division 1 vs. II, Division 2).

RESULTS

Between t1 and t2, SNB (p = 0.000) and SNPog (p = 0.000) increased significantly, as did ANB (p = 0.000), while the difference between ANB and ANB(ind) (p = 0.000) and Wits appraisal (p = 0.000) decreased significantly. The dentoalveolar variables U1-SN, U1-SpP, and the interincisal angle changed significantly in both groups. The inclination of the upper incisors was corrected by retrusion in the Class II, Division 1 and by protrusion in the Class II, Division 2 group. Only marginal changes in all variables between t2 and t3 were observed.

CONCLUSION

A significant skeletal effect (even in long-time stability) through bionator treatment could be confirmed in this study of Class II, Divisions 1 and 2 patients. The desired effect on the upper front teeth was realized, and there was no appreciable dentoalveolar compensation in the mandible.

Avaliação cefalométrica dos resultados do aparelho de protração mandibular (APM) associado ao aparelho fixo em relação às estruturas dentoalveolares e tegumentares em pacientes portadores de má oclusão de Classe II, 1ª divisão

OBJETIVO: avaliar cefalometricamente as alterações tegumentares e dentoalveolares em jovens brasileiros portadores de má oclusão de Classe II, 1ª divisão, tratados com APM associado à Ortodontia corretiva fixa. MÉTODOS: a amostra consistiu-se de 28 pacientes (16 do sexo feminino e 12 do sexo masculino), com idade média de 13,06 anos, tratados por um período médio de 14,43 meses. As alterações foram medidas em 56 cefalogramas específicos, obtidos das telerradiografias laterais feitas antes e após o tratamento, por dois examinadores calibrados para identificar as alterações tegumentares e dentoalveolares, utilizando-se grandezas cefalométricas lineares e angulares. As variáveis independentes (sexo, idade, padrão facial, tipo de APM, arco, técnica e tempo de tratamento) foram consideradas e analisadas com as grandezas cefalométricas lineares e angulares. As respostas ao tratamento foram analisadas e comparadas pelos testes Wilcoxon Signed Ranks e Mann-Whitney para um nível de significância de 5%. RESULTADOS: os resultados mostraram mudanças dentoalveolares de grande magnitude, provocando, assim, mudanças favoráveis no tecido mole. Observou-se, ainda, que as variáveis idade, tipo de APM e técnica utilizada influenciaram no tratamento. CONCLUSÕES: o APM mostrou-se uma alternativa eficaz para o tratamento da má oclusão de Classe II, 1ª divisão, propiciando alterações dentoalveolares e tegumentares com resultados clínicos satisfatórios.

Avaliação cefalométrica dos efeitos do aparelho de protração mandibular (APM) associado à aparatologia fixa em relação às estruturas esqueléticas em pacientes portadores de má oclusão Classe II, 1ª divisão

OBJETIVO: este estudo objetivou avaliar as respostas cefalométricas esqueléticas provocadas pelo Aparelho de Protração Mandibular, em jovens brasileiros portadores de má oclusão Classe II, 1ª divisão, associado à Ortodontia corretiva fixa. MÉTODOS: a amostra consistiu de 56 telerradiografias em norma lateral de 28 pacientes, sendo 16 do sexo feminino e 12 do masculino. A idade inicial média foi de 13,06 anos e o período médio da terapia com o APM foi de 14,43 meses. As telerradiografias laterais foram obtidas antes e após o tratamento, tendo sido comparadas por dois examinadores calibrados para identificar as alterações esqueléticas do APM, utilizando-se 16 grandezas cefalométricas lineares e angulares. Algumas variáveis independentes (idade do paciente, sexo, padrão facial, modelo de APM, tempo total de uso do aparelho, arco usado durante a terapia com APM e técnica ortodôntica utilizada) foram consideradas e associadas às referidas grandezas, no intuito de demonstrar a influência dessas variáveis sobre as grandezas As respostas ao tratamento foram analisadas e comparadas pelos testes Wilcoxon Signed Ranks e Mann-Whitney para um nível de significância de 5%. RESULTADOS: os resultados mostraram uma restrição no deslocamento anterior da maxila, um aumento na protrusão mandibular, uma melhora no relacionamento anteroposterior das bases ósseas e estabilidade do plano mandibular em relação à base do crânio. Observou-se, ainda, influência das variáveis idade, padrão facial e tipo de APM utilizado. CONCLUSÕES: o APM consistiu numa alternativa eficaz no tratamento da má oclusão de Classe II, 1ª divisão, propiciando alterações do componente esquelético com resultados clínicos satisfatórios.

Long-term dentoskeletal changes with the Bionator, Herbst, Twin Block, and MARA functional appliances

OBJECTIVE

To determine if the long-term dentoskeletal changes in patients treated with tooth-borne functional appliances were comparable to each other and to matched controls.

MATERIALS AND METHODS

The experimental sample consisted of 80 consecutively treated patients who were equally divided into Bionator, Herbst, Twin Block, and mandibular anterior repositioning appliance (MARA) groups. The control group comprised 21 children with untreated skeletal Class II malocclusions. Lateral cephalograms were taken for the treated group at T1 (initial records), T2 (completion of functional therapy), and T3 (completion of fixed appliance therapy). A repeated measure analysis of variance (ANOVA) was used to assess the differences between and within groups. If ANOVA results were significant, Tukey-Kramer tests were used to determine where the significant differences occurred.

RESULTS

(1) Temporary restriction of maxillary growth was found in the MARA group (T2-T1). (2) SNB increased more with the Twin Block and Herbst groups when compared with the Bionator and MARA groups. (3) The occlusal plane significantly changed in the Herbst and Twin Block groups. (4) The Twin Block group expressed better control of the vertical dimension. (5) The overbite, overjet, and Wits appraisal decreased significantly with all of the appliances. (6) The Twin Block group had significant flaring of the lower incisors at the end of treatment. (7) Over the long-term, there were no significant soft tissue changes among treated and untreated subjects.

CONCLUSIONS

No significant dentoskeletal differences were observed long-term, among the various treatment groups and matched controls.

Examination of temporomandibular disorders in the orthodontic patient: a clinical guide

The possible association between orthodontic treatment and temporomandibular disorders (TMD) is a topic of great interest in the current literature. The true role of orthodontic therapy on the etiology of TMD, however, is still uncertain. From the clinical prospective, a thorough examination of the stomatognathic system is always necessary in order to detect possible TMD signs and symptoms prior to the beginning of the orthodontic therapy. Caution should be exercised when planning, performing and finalizing orthodontics, especially in patients who with history of signs and symptoms of TMD. The clinician must always eliminate patient's pain and dysfunction before initiating any type of orthodontic mechanics. Muscle incoordination, unstable disc-condyle relationship and bone alterations are usual TMD conditions that can interfere with the presenting occlusal relationship. This article reviews these aspects and presents a detailed clinical guide for the examination of the orthodontic patient, considering aspects related to facial pain and dysfunction.

Mandibular incisor position changes in relation to amount of bite jumping during Herbst/multibracket appliance treatment: a radiographic-cephalometric study

INTRODUCTION

The aim of this study was to analyze the effect of the cast Herbst/multibracket (MB) appliance on the position of the mandibular incisors in relation to the amount of mandibular advancement at the beginning of treatment.

METHODS

We screened 133 patients with Class II Division 1 malocclusions. The subjects were divided into 3 bite-jumping groups: I, 49 subjects with bite jumping of <7 mm; II, 44 subjects with bite jumping of 7.5 to 9.5 mm; and III, 40 subjects with bite jumping of >9.5 mm. Only group I with small (S) and group III with large (L) bite jumping were considered. The average ages of the subjects in the 2 bite-jumping groups were 13.6 +/- 2.4 years in the S group and 14.7 +/- 4.7 years in the L group. The average treatment time with the Herbst/MB appliance was 19 months. Lateral headfilms were evaluated at 3 times: before Herbst treatment, after Herbst treatment, and after MB treatment.

RESULTS

During the Herbst phase, the mandibular incisors were significantly intruded, protruded, and proclined in both bite-jumping groups. Larger tooth movements occurred in group L than in group S. During the MB phase, comparable relapsing incisor tooth movements were seen in the 2 bite-jumping groups. There was moderate correlation between bite-jumping and incisor position changes during the Herbst and the Herbst/MB treatment periods. No associations were found between the amount of bite jumping and the changes of sagittal and vertical jaw relationships, age, and treatment growth period.

CONCLUSIONS

During the Herbst treatment period, there was an association between bite jumping and movement of the mandibular incisors: the greater the bite jumping, the larger the intrusion, protrusion, and proclination of teeth. During the MB treatment period, relapsing incisor tooth movements occurred that were independent of the original amount of bite jumping.

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.

"Effective" TMJ and chin position changes in Class II treatment

OBJECTIVE

To evaluate the "effective" temporomandibular joint (TMJ) changes (the sum of condylar modeling, glenoid fossa modeling, and condylar position changes within the fossa), and their influence on chin position in patients with a Class II division 1 malocclusion treated orthodontically with a multibracket appliance and Class II elastics (Tip-Edge) and orthopedically with a fixed functional appliance (Herbst).

MATERIALS AND METHODS

Two groups of successfully treated subjects were evaluated: Tip-Edge (n = 24) and Herbst (n = 40). The Bolton Standards served as a control group. Lateral head films obtained before treatment and after an observation period of 2.6 years (Herbst also after 0.6-year period) were analyzed.

RESULTS

In comparison with the Herbst and control groups, the Tip-Edge group exhibited less favorable sagittal "effective" TMJ growth and chin position changes necessary for skeletal Class II correction.

CONCLUSIONS

Orthodontic therapy with a multibracket appliance and Class II elastics seems not to have any favorable sagittal orthopedic effect on the mandible, while bite jumping with the Herbst appliance has a favorable sagittal orthopedic effect on a short-time basis.

Condylar growth and mandibular positioning with stepwise vs maximum advancement

INTRODUCTION

The aim of this study was to compare the effects of several Class II malocclusion treatments on condylar growth and positioning of the mandible.

METHODS

The material comprised series of lateral cephalograms obtained at the start, after about 6 months, and after about 12 months of treatment from 3 groups of consecutively treated patients who used a headgear-activator with stepwise mandibular advancement (HGA-S), a headgear-activator with maximum jumping of the mandible (HGA-M), and a headgear-Herbst appliance with stepwise advancement (HGH-S), respectively. Six-month growth data from matched controls were used to calculate the net treatment effects.

RESULTS

Mandibular prognathism was enhanced after stepwise advancement but not after maximum jumping, and only during the initial phase of therapy; the effect was significantly greater for the fixed functional appliance than for the removable functional appliance. Lower-facial height was increased by the HGA-S, unchanged by the HGA-M, and restrained by the HGH-S. The low construction bite of the HGH-S meant that the extent of bone apposition on the posterior and superior parts of the condyle was similar, whereas the high construction bite of the HGA-S and the HGA-M meant that the effect on the superior part was greater, but only significantly so after stepwise advancement.

CONCLUSIONS

The mode of jumping, the vertical opening, and whether the functional appliance is fixed or removable affect the amount and pattern of condylar growth, and the position of the mandible.

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

INTRODUCTION

Various anchorage techniques have been designed for canine retraction. Intraoral techniques have not always been successful, and now implants are widely used for this purpose. A new type of titanium microimplant, with a small diameter and a button-like head, was shown to be an effective source of anchorage for distal movement of the canines. The purposes of this study were to measure and compare the rates of canine retraction with titanium microimplant anchorage and conventional molar anchorage.

METHODS

The sample comprised 12 patients (8 female, 4 male; mean age, 19.7 years; range, 16-22 years) who were scheduled for extraction of all first premolars. After leveling and aligning, titanium microimplants 1.2 mm in diameter and 9 mm in length were placed between the roots of the second premolar and the first molars. The implants were placed in the maxillary and mandibular arches on the same side in 10 patients and in the maxilla only in 2 patients. A brass wire guide and a periapical radiograph were used to determine the implant position. After 15 days, the implants and the molars were loaded with closed coil springs with a force of 100 g for canine retraction. Preretraction and postretraction lateral cephalograms were taken and superimposed for measuring the amount of retraction. The amount of canine retraction was measured from pterygoid vertical in the maxilla and SN perpendicular in the mandible.

RESULTS

Mean canine retraction amounts were 4.29 mm in the maxilla and 4.10 mm in the mandible on the implant-anchorage side, and 3.79 mm in the maxilla and 3.75 mm in the mandible on the molar-anchorage side. The rates of canine retraction were 0.93 mm per month in the maxilla and 0.83 mm per month in the mandible on the implant-anchored side, and 0.81 mm per month in the maxilla and 0.76 mm per month in the mandible on the molar-anchored side.

CONCLUSIONS

Canine retraction proceeds at a faster rate when titanium microimplants are used for anchorage.

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.

Comparison of soft-tissue profiles after treatment with headgear or Herbst appliance

INTRODUCTION

Herbst and headgear appliances are considered effective for correcting Class II malocclusions in growing patients, although their skeletal and dental effects differ. In the literature, there is no comparison between profile esthetic outcomes with the Herbst and headgear. The purpose of this study was to provide that comparison.

METHODS

Lateral cephalometric radiographs of 48 matched pairs of growing Class II Division 1 patients treated with either the Herbst appliance or headgear (both combined with fixed appliances) were used to generate pretreatment and posttreatment standardized silhouettes. The silhouettes were randomly arranged and judged by lay people and orthodontic residents using a 7-point Likert scale. Statistical analyses including nonparametric procedures and intraclass correlation were used to compare initial, final, and change profile esthetic scores for the 2 groups of subjects and agreement between evaluators.

RESULTS

Both groups of subjects had significant profile improvements with treatment (P <.05), and there were no statistically significant differences between the groups in average final profile scores. Overall, there was strong agreement between the evaluations of laypersons and orthodontic residents.

CONCLUSIONS

Class II Division 1 growing patients treated with either Herbst appliance or headgear (both combined with fixed appliances) will benefit from significantly improved profiles that are equally attractive.

Skeletal and Dental Changes in Class II division 1 Malocclusions Treated with Splint-Type Herbst Appliances

OBJECTIVE

To evaluate skeletal and dental changes in growing individuals through lateral cephalograms obtained after the sole use of the splint-type Herbst appliances in Class II division 1 malocclusions.

METHODS

Several electronic databases (Pubmed, Medline, Medline In-Process & Other Non-Indexed Citations, Cochrane Library Database, Embase, Web of Sciences, Scopus, and Lilacs) were searched with the help of a health sciences librarian. Abstracts that appeared to fulfill the initial selection criteria were selected by consensus. The original articles were then retrieved. Their references were also hand-searched for possible missing articles. Clinical trials that assessed, through lateral cephalograms, immediate skeletal and dental changes with the use of splint-type Herbst appliances without any concurrent orthodontic appliances, surgical intervention, or syndromic characteristics were considered. A comparable untreated Class II division 1 malocclusion control group was required to factor out normal growth changes.

RESULTS

Three articles were finally selected and analyzed. An individual analysis of these articles was made and some methodological flaws were identified. The selected studies all showed statistically significant changes in the anteroposterior length of the mandible, vertical height of the ramus, lower facial height, mandibular incisor proclination, mesial movement of the lower molars, and distal movement of the upper molars. Posttreatment relapse in overjet and molar relationship was also observed.

CONCLUSIONS

Dental changes are as important as skeletal changes to attaining the final occlusal results. Long-term, prospective, double-blinded, randomized clinical trials are needed to support these conclusions.