A long-term follow-up study of Class II malocclusion correction after treatment with Class II elastics or fixed functional appliances

Predictors of changes in incisor inclination during orthodontic levelling and alignment with fixed appliances: a retrospective cross-sectional study

INTRODUCTION

Labial tipping of the incisors, observed during levelling and alignment in orthodontic treatment with multibracket-appliances, can be an undesired side effect due to its association with relapse and attachment loss in excessive cases. Therefore, its pre-treatment prediction is useful to individualise treatment plans correspondingly. This retrospective cross-sectional study aimed to establish regression equations predicting incisors' inclination changes during levelling and alignment with fixed appliances in orthodontic patients using lateral cephalograms. Potential predictors analysed included clinical and cephalometric parameters.

METHODS

Patients of any age and malocclusion were screened for inclusion, and the upper and lower arches were evaluated separately. Lateral cephalograms taken at T0 and T1, initial plaster models and patient records were analysed. Multiple linear regression models were performed to establish regression equations, identifying predictors of incisors' inclination changes.

RESULTS

The final study population was comprised of 216 female (n = 123, 56.9%) and male (n = 93, 43.1%) orthodontic patients (147 upper, 151 lower arches) aged between 9.3 and 30.0 years with a mean age of 13.1 years ± 2.1. Interrater- and intrarater-reliability showed perfect measurement concordance for all cephalometric parameters and moderate to perfect concordance for categorical variables. Sagittal changes of the upper incisors' inclination (Δ1-NL) were dependent on initial anterior crowding, initial incisor inclination and intermaxillary elastics (corrected R2 = 0.375, n = 147). In the lower jaw, incisors' proclination (Δ1-ML) was predicted by anterior crowding, incisor inclination, growth pattern, skeletal class and bracket type (corrected R2 = 0.468, n = 151). Changes in the interincisal angle (Δ1-1) were significantly predicted by mandibular anterior crowding and initial inclination of the upper and lower incisors (corrected R2 = 0.440, n = 82).

CONCLUSIONS

Regression equations with specific clinical and cephalometric parameters are suitable to predict the degree of incisors' inclination changes during alignment with fixed appliances. The amount of anterior crowding and the initial incisors' inclination of the respective jaw were relevant in all three formulas. Using the predictors may reduce undesired excessive inclination changes and help in individualised treatment planning. However, as more than 50% of the variance are explained by other factors, they act as an adjunctive method to the remaining procedures of treatment planning.

Sustained Protraction Increases Lengthening of the Mandibular Condylar Process Whilst Changes Its Growth Direction in a Rat Model

OBJECTIVE

In Class II elastics treatment, the mandible is subject to sustained protraction. The study aimed to investigate the morphological and histological changes resulting from sustained mandibular protraction, through establishment of a novel model in rat.

MATERIALS AND METHODS

Forty-eight 4-week-old male Sprague-Dawley rats were randomly divided into three groups, including the 50 and 100 cN protraction groups, and the control. In the two protraction groups, NiTi coil springs were fixed between the metal bands on the maxillary incisors and mandibular molars to pull the mandible forward. CBCT scans were taken immediately before (T0), 2 weeks (T1) and 4 weeks (T2) after the traction. Histological and immunohistochemical analyses were performed at T1 and T2.

RESULTS

Increase of the condylar process length and angular process length were significantly larger in the two protraction groups than that in the control; however, the condylar process angle (∠CPA) was significantly reduced by the protraction at T2, leading to decreased condylar height. The protraction decreased the condylar cartilage thickness at T1, which recovered to the control level at T2, with no significant changes detected in the expression of SRY-related high mobility group-box gene 9 (SOX9) and type II collagen (COL II), two chondrogenic markers.

CONCLUSION

The established rat model is manoeuvrable and reliable, which exerts sustained and measurable mandibular protraction. The sustained protraction increases the lengthening of the mandibular condylar process, but alters its growth direction by causing it to turn downwards.

Root resorption in Class II malocclusion treatment with and without maxillary premolar extractions

INTRODUCTION

Class II malocclusion treatment efficiency with maxillary premolar extractions has been reported. However, no study evaluated the root resorption associated with this protocol. Therefore, this study aimed to compare the degree of root resorption of the maxillary incisors in Class II malocclusion treatment with and without maxillary premolar extractions.

METHODS

The sample consisted of 56 patients with complete Class II malocclusion, divided into 2 groups. Group 1 comprised 28 patients (10 female, 18 male) treated with maxillary first premolar extractions, and group 2 was composed of 28 patients (16 female, 12 male) treated without extractions. The groups were matched regarding initial age, treatment time, crowding, initial malocclusion severity, finishing quality, initial overjet, and overbite. Periapical radiographs of the maxillary incisors were used to assess the degree of root resorption using a scoring system. In addition, treatment changes involving maxillary incisors were evaluated in lateral headfilms. Intergroup comparisons were performed with t, Mann-Whitney U, and chi-square tests (P <0.05).

RESULTS

Overjet, overbite, inclination, vertical positional changes, and vertical and horizontal apical displacements of maxillary incisors were similar between groups. There was no statistically significant difference between groups regarding root resorption of maxillary incisors. Root resorption degree ranged from mild to moderate in both groups.

CONCLUSIONS

Treating complete Class II malocclusion with 2 maxillary premolar extractions resulted in a similar root resorption as treating without maxillary premolar extractions. An individualized evaluation of root resorption predisposing factors should be performed for each patient.

Stability of Class II malocclusion treatment with Class II elastics

INTRODUCTION

The objective of this study was to compare the long-term cephalometric stability after successful therapy of nonextraction Class II malocclusion with elastics and with headgear.

METHODS

The sample comprised 43 patients with Class II malocclusion and was divided into 2 groups. The elastic group (EG) consisted of 20 patients treated with fixed appliances associated with Class II elastics, and the headgear group (HG) consisted of 23 patients treated with fixed appliances and extraoral headgear. Pretreatment, posttreatment, and long-term posttreatment lateral radiographs were evaluated; t tests were used to compare the long-term posttreatment changes between the groups.

RESULTS

The groups were matched regarding initial age, time of long-term posttreatment evaluation, initial malocclusion severity, quality of treatment result, and all pretreatment cephalometric variables. Intergroup comparisons of long-term posttreatment changes showed that the HG group presented significantly greater mandibular protrusion, occlusal plane angle decrease, and maxillary molar mesialization. However, long-term posttreatment stability was similar in overjet, overbite, and molar relationships.

CONCLUSIONS

Nonextraction Class II malocclusion treatment with elastics or extraoral headgear have similar long-term posttreatment stability.

Dental and Skeletal Effects of Herbst Appliance, Forsus Fatigue Resistance Device, and Class II Elastics-A Systematic Review and Meta-Analysis

Background: Our study aimed to systematically summarize the dentoskeletal effects of Herbst appliance; Forsus fatigue resistance device; and Class II elastics in adolescent Class II malocclusion. Methods: Five databases; unpublished literature; and reference lists were last searched in August 2022. Randomized clinical trials and observational studies of at least 10 Class II growing patients that assessed dentoskeletal effects through cephalometric/CBCT superimpositions were eligible. The included studies quality was assessed with the RoB 2 and ROBINS-I tools. A random-effects model meta-analysis was performed. Heterogeneity was explored with subgroup and sensitivity analyses. Results: Among nine studies (298 patients); two-to-three studies were included in each meta-analysis. Less post-treatment upper incisor retroclination (<2) and no overbite; overjet; SNA; SNB; and lower incisor inclination differences were found between Herbst/Forsus and Class II elastics. No differences in maxilla; condyle; glenoid fossa; and most mandibular changes were found between Herbst and Class II elastics; except for a greater 1.5 mm increase in mandibular length and right mandibular ramus height (1.6 mm) with Herbst. Conclusions: Herbst and Class II elastics corrected the molar relationship; but Herbst moved the lower molars more mesially. Apart from an additional mandibular length increase; no other dental and anteroposterior skeletal difference was found. Forsus was more effective in molar correction; overjet reduction; and upper incisor control than Class II elastics. Trial registration number OSF: 10.17605/OSF.IO/8TK3R.

Biomechanical analysis of effective mandibular en-masse retraction using Class II elastics with a clear aligner: a finite element study

Background

This study aimed to evaluate the displacement and stress distribution of mandibular dentition by various positions of the Class II elastics during en-masse retraction in clear aligner therapy.

Methods

Models including a mandibular dentition (without first premolars), periodontal ligament (PDL), mandible, as well as attachments, aligners and buttons were constructed and imported into Ansys Workbench 2019 (ANSYS, USA) to generate the three-dimensional (3D) finite element model. Six combinations were created: (1) aligner alone (control), (2)-(5) Class II elastics with buttons placed on the mesiobuccal (MB), distobuccal (DB), mesiolingual (ML) and distolingual (DL) surface of the mandibular first molar, and (6) Class II elastics with a button on the aligner corresponding to the mesiobuccal surface of the mandibular first molar (AMB). The elastic force was set to 2 N for simulations.

Results

The central incisors appeared lingual tipping in the six models. The lingual crown movement of the central incisors was 0.039 mm, 0.034 mm, 0.034 mm, 0.042 mm, 0.041 mm, and 0.034 mm for control model, MB model, DB model, ML model, DL model, and AMB model, respectively. The first molars showed mesial tipping in the six models. The mesial movement of the mesiobuccal cusps of the first molars was 0.045 mm, 0.060 mm, 0.063 mm, 0.048 mm, 0.051 mm, and 0.055 mm for control model, MB model, DB model, ML model, DL model, and AMB model, respectively.

Conclusions

Class II elastics reduced lingual tipping of anterior teeth but aggravated mesial tipping of posterior teeth. Mesiolingual elastics developed minimum mesial tipping of the posterior teeth. When Class II elastics are required, attaching elastics on the mesiolingual surface of the mandibular first molar is recommended to prevent mandibular anchorage loss.

Mandibular incisor inclination and gingival recession after treatment with the Jasper Jumper: a 10-year follow-up

OBJECTIVE

To evaluate the long-term outcomes of Class II treatment with the Jasper Jumper appliance and comprehensive orthodontic treatment concerning inclination of the mandibular incisors and gingival recession.

METHODS

Sixteen patients with Class II malocclusion at a mean age of 12.54y (SD = 1.17) were treated with the Jasper Jumper appliance and comprehensive orthodontic treatment. The mean treatment time was 2.05y (SD = 0.21). Dental records were taken before (T1), after treatment (T2) and 11.90y (SD = 0.48) after debonding (T3). The frequency of gingival recession, clinical crown height and mandibular incisor position were evaluated using intraoral photographs, digital models and lateral cephalograms. Interphase changes were evaluated using dependent t and McNemar's tests. Correlation between clinical crown height and final position of the mandibular incisors was evaluated using Pearson correlation test (P < 0.05).

RESULTS

The frequency of gingival recessions increased over time and was observed in 6 (9.4%), 12 (18.8%) and 24 (37.5%) of the mandibular incisors at T1, T2 and T3, respectively. A significant increase in labial inclination and protrusion of the mandibular incisors was observed between T1 and T2 interval. The clinical crown height significantly increased in the follow-up period (T3-T2) and in the complete observation time (T3-T1). There was no correlation between the amount of labial inclination and protrusion of the mandibular incisors and clinical crown height for all time intervals.

CONCLUSION

No significant correlation between the amount of labial movement of the mandibular incisor and clinical crown height increase was found.

Attractiveness of the facial profile: comparison of Class II patients treated with Twin Force® or intermaxillary elastics

Objective:

To compare the facial profile attractiveness of Class II patients treated with Twin Force^® or intermaxillary elastics.

Methods:

Sample comprised 47 Class II patients divided into two groups: G1) TWIN FORCE - 25 patients treated with fixed appliances and Twin Force^® fixed functional appliance (mean initial age was 17.91 ± 7.13 years, mean final age was 20.45 ± 7.18 years, and mean treatment time was 2.53 ± 0.83 years); G2) ELASTICS - 22 patients treated with fixed appliances and Class II intermaxillary elastics (mean initial age was 15.87 ± 5.64 years, mean final age was 18.63 ± 5.79 years and mean treatment time was 2.75 ± 0.60 years). Lateral cephalograms from pretreatment and posttreatment were used. Cephalometric variables were measured and silhouettes of facial profile were constructed and evaluated by 48 laypeople and 63 orthodontists, rating the attractiveness from 0 (most unattractive profile) to 10 (most attractive profile). Intergroup comparisons were performed with Mann-Whitney and independent t-tests.

Results:

At pretreatment, facial profile of the Twin Force^® group was less attractive than the Elastics group. Treatment with Twin Force^® or Class II elastics resulted in similar facial profile attractiveness, but the facial convexity was more reduced in the Twin Force^® group. Orthodontists were more critical than laypeople.

Conclusions:

Treatment with Twin Force^® or Class II elastics produced similar facial profile attractiveness at posttreatment. Profile attractiveness was reduced with treatment in the elastic group, and improved in the Twin Force^® group. Facial convexity was more reduced with treatment in the Twin Force^® group.

Effective and Efficient Correction of Severe Skeletal Class II Division 1 Malocclusion with Intermaxillary Elastics

Treatment of Class II malocclusion accompanied with a skeletal discrepancy is challenging. The approach of correction depends on several factors such as the status and pattern of growth, severity of the malocclusion, and patient cooperation. This case report describes a successful management of a 12-year-old young adolescent boy that was presented with a Class II division 1 malocclusion with an underlying skeletal discrepancy in horizontal and vertical dimensions. Growth modification was achieved by means of bite opening and unlocking the mandible together with Class II elastics and mechanics. Treatment was highly effective and efficient by achieving all treatment goals within a period of 18 months.

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.

Quality of occlusal outcome following space closure in cases of lower second premolar aplasia using lingual orthodontic molar mesialization without maxillary counterbalancing extraction

Background

Controlled space closure in cases of isolated lower second premolar aplasia (ILSPA) without maxillary counterbalancing extraction is challenging. Anterior anchorage loss may occur during space closure resulting in compromised occlusal results in terms of an absence of proper canine guidance during laterotrusive mandible movements.

In order to evaluate the effectiveness of Herbst telescope anchorage in combination with double-cable, pull mechanics and a completely customized lingual appliance for orthodontic space management in cases of ILSPA, we tested the null hypothesis that there is a significant deterioration in the sagittal canine relationship towards an Angle-Class-II occlusion expressed as a loss of anterior anchorage following space closure with molar mesialization.

Methods

Twenty-five consecutively de-bonded subjects (female / male 17 / 8; aged at T0 (start of MB Tx) 12.3 to 20.6 years; mean age 15.0 / SD 1.7 years) were included in this retrospective analysis using the inclusion criteria of least of one lower second premolar aplasia; completed treatment with a totally customized lingual appliance (CCLA) in combination with Herbst telescopes. Exclusion criteria were the absence of counterbalancing maxillary extractions, as well as additional tooth aplasia other than lower second premolars. A total of 33 single, lower premolar aplasia space closures (right / left sided 17 / 16) were assessed using plaster casts and intra-oral photographs scaled to the plaster casts, at bonding (T0), Herbst insertion (T1), following gap closure (T2) and de-bonding (T3). Parallelism of roots was controlled by panoramic x-rays at T3.

Results

The mean aplasia space at T0 was 7.5 mm (SD 2.6). Complete space closure was achieved in all 33 situations. The null hypothesis was rejected. There was a significant improvement in the initial canine relationships (mean 3.5 mm distal occlusion at T0) to a mean 0.1 mm at T3. When evaluated against the individual treatment plan, the following amounts of planned improvements were achieved: space closure 100%, canine relationship 97.5%, overjet 93.9%, overbite 96.4%, parallel roots in space closure site 93.9%.

Conclusion

Herbst telescope anchorage in combination with double-cable pull mechanics and a CCLA for orthodontic space closure can deliver predictable, high-quality treatment results.

A cephalometric study of the skeletal and dento-alveolar effects of the modified Louisiana State University activator in Class II malocclusion

Objectives

To analyse the skeletal and dento-alveolar effects of the modified Louisiana State University activator (MLSUA) in Class II treatment.

Materials and methods

A test group of 46 participants (25 females, 21 males) with Class II malocclusion treated with MLSUA followed by fixed appliances was compared with a matched Class II control group. Lateral cephalograms were taken at T1 (initial records), T2 (completion of MLSUA treatment), and T3 (before deband). The participants were also divided into two groups: pre-pubertal and pubertal according to skeletal maturity and three groups of different vertical facial patterns at the start of the treatment: brachyfacial, mesofacial, and dolichofacial. Statistical comparisons were performed with t-tests and analysis of variance (ANOVA).

Results

Statistically significant supplementary mandibular growth (Co-Gn) in the test group (2.6 mm) was associated with improvement of overjet (OJ), overbite (OB), and molar relationship. Short-term mandibular growth was greater in pubertal than pre-pubertal groups (2.4 mm, P < 0.05). Mandibular incisors retroclined by 2.1 degrees after MLSUA treatment. The brachyfacial group showed greater reduction in the ANB angle and forward movement of pogonion. Mandibular, palatal, and occlusal plane angles showed insignificant change regardless of the facial type.

Conclusions

MLSUA treatment corrected the Class II malocclusion by accelerating mandibular growth in the short-term with minimal dento-alveolar compensation, and the correction was maintained before deband. The treatment may be more effective if started at puberty. The mandibular, palatal, and occlusal planes remained stable throughout the treatment. Brachyfacial patients showed more favourable horizontal growth.

Dentoskeletal effects during Herbst-Multibracket appliance treatment: a comparison of lingual and labial approaches

OBJECTIVES

To analyse and compare the effects during Herbst treatment (Tx) when combined with lingual (completely customized) or labial (straight-wire) multibracket appliances (MBA).

SUBJECTS AND METHODS

18 Class II division 1 patients (Overjet ≥ 5mm, Class II molar relationship ≥ 0.5 cusp width bilaterally or 1 cusp width unilaterally, median age 16.0 years) treated with lingual (completely customized) MBA in combination with a Herbst appliance were matched (sagittal molar relationship and skeletal maturity) to 18 Class II division 1 Herbst patients treated with labial (straight-wire) MBA. Lateral cephalograms from before, during and after all active Tx were analysed using the SO-analysis and standard cephalometric variables.

RESULTS

During the Herbst phase (LINGUAL: mean = 13.9 months, LABIAL: mean = 8.5 months) smaller average Overjet and molar relationship changes were seen in the LINGUAL (5.3mm/4.4mm) than in the LABIAL (8.0mm/5.9mm) group. This was due to the fact that the LABIAL patients were treated to overcorrected sagittal relationships. During the total Tx period (Herbst + MBA; LINGUAL: mean = 3.1 years, LABIAL: mean = 1.9 years) the average amounts of Overjet and molar relationship changes were similar in both groups (LINGUAL: 4.0mm/3.3mm, LABIAL: 5.1mm/3.7mm). Overjet correction was achieved by 45% (LINGUAL) and 37% (LABIAL) skeletal changes; the respective amounts for molar relationship correction were 55% (LINGUAL) and 51% (LABIAL).

CONCLUSION

For most variables, similar effects occurred during Herbst Tx whether combined with lingual (completely customized) or labial (straight-wire) MBA.

Class II Division 1: An Evidence- Based Review of Management and Treatment Timing in the Growing Patient

Class II division 1 malocclusion is common and various methods have been suggested for successful treatment in the growing patient. A number of recent high-quality studies have been undertaken to assess the efficacy of these treatments. We aim to outline the existing best evidence that supports current practice, with a review of the effect of treatment timing on outcome. This will provide a sound evidence-base for General Dental Practitioners for assessing, advising and referring young patients for treatment. CPD/CLINICAL RELEVANCE: General Dental Practitioners should understand the management options and optimal time for treating growing patients with a Class II division 1 malocclusion.

Maxillary molar distalization therapy in adult patients: a multicentre study

OBJECTIVES

To evaluate dento-skeletal changes following conventional anchorage molar distalization therapy in adult patients.

SETTING AND SAMPLE POPULATION

Thirty-three patients (25 women, mean age 23 years 1 months ± 3 months; 8 men, mean age 28 years 3 months ± 7 months) were recruited from 4 Board Certified specialists. All subjects underwent molar distalization therapy using intra-oral distalizing appliances.

SUBJECTS AND METHODS

Cephalometric headfilms were available for all subjects before (T1) and at the end of comprehensive treatment (T2). The initial and final measurements and treatment changes were compared by means of a paired t-test.

RESULTS

Mean total treatment time was 3 years 2 months ± 6 months. Maxillary first molar distalized 2.9 ± 0.6 mm contributing 64.4% to Class II molar correction, whereas mandibular first molar showed a concomitant mesial movement of 1.6 ± 0.5 mm. Maxillary incisors retroclined an average of 5.8° ± 3.9°, lower incisors proclined 4.1° ± 1.1° and the occlusal plane rotated downwards and backwards 1.8° ± 2.1°. Clockwise rotation of the mandible (1.7° ± 0.5°) and increase in lower facial height (2.5 ± 1.5 mm) were also observed.

CONCLUSIONS

Maxillary molar distalization therapy can be successfully performed in adult patients despite a slight increase in vertical facial dimension should be considered.

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.

Three-dimensional treatment outcomes in Class II patients treated with the Herbst appliance: a pilot study

INTRODUCTION

The aims of this study were to analyze 3-dimensional skeletal changes in subjects with Class II malocclusion treated with the Herbst appliance and to compare these changes with treated Class II controls using 3-dimensional superimposition techniques.

METHODS

Seven consecutive Herbst patients and 7 Class II controls treated with Class II elastics who met the inclusion criteria had cone-beam computed tomographs taken before treatment, and either after Herbst removal or at posttreatment for the control subjects. Three-dimensional models were generated from the cone-beam computed tomography images, registered on the anterior cranial bases, and analyzed using color maps and point-to-point measurements.

RESULTS

The Herbst patients demonstrated anterior translation of the glenoid fossae and condyles (right anterior fossa, 1.69 ± 0.62 mm; left anterior fossa, 1.43 ± 0.71 mm; right anterior condyle, 1.20 ± 0.41 mm; left anterior condyle, 1.29 ± 0.57 mm), whereas posterior displacement predominated in the controls (right anterior fossa, -1.51 ± 0.68 mm; left anterior fossa, -1.31 ± 0.61 mm; right anterior condyle, -1.20 ± 0.41 mm; left anterior condyle, -1.29 ± 0.57 mm; P <0.001). There was more anterior projection of B-point in the Herbst patients (2.62 ± 1.08 mm vs 1.49 ± 0.79 mm; P <0.05). Anterior displacement of A-point was more predominant in the controls when compared with the Herbst patients (1.20 ± 0.53 mm vs -1.22 ± 0.43 mm; P <0.001).

CONCLUSIONS

Class II patients treated with the Herbst appliance demonstrated anterior displacement of the condyles and glenoid fossae along with maxillary restraint when compared with the treated Class II controls; this might result in more anterior mandibular projection.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Correction of Class II malocclusion with Class II elastics: a systematic review

INTRODUCTION

Although Class II elastics have been widely used in the correction of Class II malocclusions, there is still a belief that their side effects override the intended objectives. The aim of this systematic review was to evaluate the true effects of Class II elastics in Class II malocclusion treatment.

METHODS

A search was performed on PubMed, Scopus, Web of Science, Embase, Medline, and Cochrane databases, complemented by a hand search. Study eligibility criteria were the application of Class II elastics in Class II malocclusion treatment and the presentation of dental or skeletal outcomes of treatment. All age groups were included.

RESULTS

The search identified 417 articles, of which 11 fulfilled the inclusion criteria. Four studied the isolated effects of Class II elastics, and 7 were comparisons between a single use of elastics and another method for Class II malocclusion correction. Because of the differences in treatment modalities in these articles, a meta-analysis was not possible.

CONCLUSIONS

Based on the current literature, we can state that Class II elastics are effective in correcting Class II malocclusions, and their effects are primarily dentoalveolar. Therefore, they are similar to the effects of fixed functional appliances in the long term, placing these 2 methods close to each other when evaluating treatment effectiveness. Little attention has been given to the effects of Class II elastics on the soft tissues in Class II malocclusion treatment.

Class II treatment by extraction of maxillary first molars or Herbst appliance: dentoskeletal and soft tissue effects in comparison

AIM

To compare dentoskeletal and soft tissue treatment effects of two alternative Class II division 1 treatment modalities (maxillary first permanent molar extraction versus Herbst appliance).

METHODS

One-hundred-fifty-four Class II division 1 patients that had either been treated with extractions of the upper first molars and a lightwire multibracket (MB) appliance (n = 79; 38 girls, 41 boys) or non-extraction by means of a Herbst-MB appliance (n = 75; 35 girls, 40 boys). The groups were matched on age and sex. The average age at the start of treatment was 12.7 years for the extraction and for 13.0 years for the Herbst group. Pretreatment (T1) and posttreatment (T2) lateral cephalograms were retrospectively analyzed using a standard cephalometric analysis and the sagittal occlusal analysis according to Pancherz.

RESULTS

The SNA decrease was 1.10° (p = 0.001) more pronounced in the extraction group, the SNB angle increased 1.49° more in the Herbst group (p = 0.000). In the extraction group, a decrease in SNB angle (0.49°) was observed. The soft tissue profile convexity (N-Sn-Pog) decreased in both groups, which was 0.78° more (n. s.) pronounced in the Herbst group. The nasolabial angle increased significantly more (+ 2.33°, p = 0.025) in the extraction group. The mechanism of overjet correction in the extraction group was predominantly dental (65% dental and 35% skeletal changes), while in the Herbst group it was predominantly skeletal (58% skeletal and 42% dental changes) in origin.

CONCLUSION

Both treatment methods were successful and led to a correction of the Class II division 1 malocclusion. Whereas for upper first molar extraction treatment more dental and maxillary effects can be expected, in case of Herbst treatment skeletal and mandibular effects prevail.

Skeletal and dental outcomes of a new magnetic functional appliance, the Sydney Magnoglide, in Class II correction

INTRODUCTION

The purpose of this prospective study was to evaluate the dentoskeletal effects of a new magnetic functional appliance, the Sydney Magnoglide (Macono Orthodontic Lab, Sydney, Australia), after both active treatment with the appliance and comprehensive fixed appliance therapy, compared with a group of untreated Class II controls.

METHODS

Thirty-four consecutively treated Class II Division 1 patients treated with the Sydney Magnoglide followed by fixed appliances were compared with 30 untreated Class II controls with the same initial dentoskeletal Class II features and matched for age and sex. Lateral cephalograms were taken before treatment, immediately after functional appliance therapy, and after comprehensive fixed appliance therapy. Cephalometric analyses included the Pancherz analysis and linear and angular measurements. The comparisons were made with Student t tests (P <0.05). There were 3 dropouts, for a final sample for statistical analysis of 31 subjects.

RESULTS

There was no statistically significant difference between the treated and control groups before treatment. Treatment with the Sydney Magnoglide and comprehensive fixed appliance therapy normalized the overjet and corrected the Class II relationship in all treated subjects. The ANB angle showed a reduction of 1.0°, as opposed to an increase of 0.3° in the untreated controls, and was associated with a statically significant improvement in the SNB angle (P <0.05). There was a significant gain of 2.3 mm in mandibular length in the treated group compared with the control group (P <0.01).

CONCLUSIONS

The outcomes of this prospective study demonstrate that the compliance-free Sydney Magnoglide is an effective functional appliance for Class II correction.

Management of severe Class II malocclusion with fixed functional appliance: Forsus

BACKGROUND

Management of class II malocclusion in adolescent patients by growth modulation is one of the most debated topics in orthodontics. Noncompliance has been a major concern for orthodontists.

CASE REPORT

This case report describes the management of severe class II malocclusion in adolescent patient using functional appliance system-Forsus to correct class II problems, which is clipped on to bands. This appliance has several advantages, as the patient cannot remove it. It acts on the teeth and jaws for 24 hours each day, patient cooperation is not a problem, and as a result the treatment time is short. There is lot of controversy about the use of functional appliances.

CONCLUSION

This case report illustrates that even today, functional appliances have a significant role in the management of class II malocclusion by using growth modulation. The growth modulation minimizes the necessity of extraction of permanent teeth and probably orthognathic surgery.

CLINICAL SIGNIFICANCE

Functional appliances have a significant role in the management of class II malocclusion. The growth modulation minimizes the necessity of extraction of permanent teeth and probably orthognathic surgery.

Sagittal and vertical occlusal cephalometric analyses of Pancherz: Norms for Chinese children

INTRODUCTION

The aims of this research were to establish norms for the sagittal and vertical occlusal cephalometric analyses of Pancherz for Chinese children and compare them with those of a matched white sample.

METHODS

The material comprised lateral cephalograms of a random sample of 405 southern Chinese children (age, 12 years; 200 boys, 205 girls) and an additional sample of 86 British white children (age, 12 years; 43 boys, 43 girls) in Hong Kong. The radiographs were digitized twice.

RESULTS

Statistically significant sex differences were found for 9 of 11 parameters in the sagittal occlusal analysis, and 6 of 10 in the vertical occlusal analysis in the Chinese sample, whereas there were no sex differences in the sagittal occlusal analysis and only 2 differences in the vertical occlusal analysis in the white sample. Statistically significant ethnic differences were found for 5 parameters in boys and 8 in girls of the 11 parameters in the sagittal analysis. For the vertical analysis, 7 of 10 parameters in both sexes differed significantly.

CONCLUSIONS

For the sagittal and vertical occlusal analyses of Pancherz, separate sex-specific standards are needed for Chinese and white children.