Effects of activator and high-pull headgear combination therapy: skeletal, dentoalveolar, and soft tissue profile changes

Treatment of Vertical Maxillary Excess and Skeletal Class II Malocclusion: A Case Report

Class II malocclusion is a recurrent problem that may occur at a young age. If treated initially, the malocclusion can be corrected by redirecting the growth without invasive modalities and avoiding orthognathic surgeries. A female patient aged 10 years three months came to the department of orthodontics having a complaint of upper front teeth placed forwardly, diagnosed with skeletal class II due to retrusive mandible and vertical maxillary excess with hyper divergent growth pattern with increased anterior facial height, with Angle's molar class II division 1 malocclusion, increased overjet of 13 mm and overbite of 7 mm, acute nasolabial angle, deep mentolabial sulcus, and hyperactive mentalis. It was treated using an activator with medium-high-pull headgear (modified Herren activator) passing through the maxillary center of resistance. A fixed mechanotherapy with high-pull headgear was given using the anterior inclined plane acrylic plate in the maxilla and McLaughlin, Bennett, and Trevisi (MBT). Begg's wrap was used for the retention plan. This case report shows the significance of proper treatment results obtained due to correct identification and planning in treating malocclusion. This case report shows the significance of proper treatment results obtained due to correct identification and planning in treating malocclusion.

Does mandibular advancement with clear aligners have the same skeletal and dentoalveolar effects as traditional functional appliances?

BACKGROUND

The study aimed to compare the dentoskeletal effects of Vanbeek Activator, Herbst, Twin-Block and Mandibular Advancement with clear aligners in children with skeletal Class II malocclusions.

METHODS

A sample with sixty-three patients (37 males, 26 females) was included and divided into untreated control group (C, n = 12), Vanbeek Activator group (V, n = 14), Herbst group (H, n = 11), Twin-Block group (TB, n = 12) and MA group (MA, n = 14). Cephalometric analysis and Johnston Pitchfork analysis were performed to quantify the skeletal and dentoalveolar components in molar relationship and overjet correction. Compare the differences of cephalometric data and Johnston-analysis data.

RESULTS

The treatment changes showed significant differences in SNB, FH-NP, NA-PA, Co-Go, Co-Pog, ANB, lower facial height ratio, U1-PP, U6-PP, L1-MP and U1-L1. All the appliances improved overjet relationships significantly (Vanbeek, Herbst, Twin-Block and MA were 2.77 mm, 5.53 mm, 4.73 mm and 3.66 mm respectively) with significant retraction of maxillary incisors. The lower incisor displacement of group V and MA was negative, while that of group H and TB was positive and there were significant differences. Molar relationships were also improved by 3.45 mm, 6.85 mm, 3.48 mm and 0.92 mm for Vanbeek, Herbst, Twin-Block and MA. Mandible displacement showed a trend of group H > TB > V > MA. The displacement of maxillary molars in group H was greater than that in group C, TB and MA, and that of mandibular ones was greater than that in group C, V and MA, significantly. Herbst, Twin-Block and MA have more significant dentoalveolar effect than Vanbeek, while Vanbeek has more skeletal effect than the others especially in restraining maxillary growth.

CONCLUSIONS

Four appliances are all effective in mandibular advancement, modification of class II molar relationship and deep overjet, with unavoidable increase in lower facial ratio. Vanbeek Activator has the most skeletal effects. Vanbeek and MA have a good control of mandibular incisors while more compensatory lower incisors proclination in Herbst and Twin-Block. Herbst has greater maxillary molar distalization. MA allows aligning and leveling meanwhile leading the mandible forward.

Cephalometric effects of Twin-block and van Beek Headgear-Activator in the correction of Class II malocclusion

INTRODUCTION

The Twin-block (TB) and the van Beek Headgear-Activator (vBHGA) are indicated for patients with Class II malocclusion with a retrognathic mandible. Although the former is commonly prescribed for horizontally growing patients, the latter is often recommended for those growing vertically. This study aimed to compare the skeletal, dentoalveolar, and soft-tissue short-term effects of TB and vBHGA, taking growth patterns into account.

METHODS

Immediate prefunctional (T1) and postfunctional appliance (T2) lateral cephalometric radiographs were retrospectively obtained for vBHGA (n = 46), TB (n = 45), and untreated control (n = 45) groups. The interaction of several variables at T1, T2, and T2 - T1, as well as the resultant treatment effect, were analyzed using the analysis of covariance regression models at the 5% significance level.

RESULTS

Except for a greater reduction in Wits measurement (3.0 mm; P <0.0001) in the TB group, no anteroposterior (AP) skeletal difference was observed between the 2 appliances (ANB, 0.530; P = 0.07) (Harvold, 0.13 mm; P = 0.81). Both improved the AP skeletal relationship (ANB and Harvold) compared with the control (P <0.05). Although this mostly occurred because of the forward positioning of the mandible with the TB (SNB, 0.960; P = 0.01), the maxillary restriction was the main mechanism with the vBHGA (SNA, 1.590; P <0.01). Dentoalveolar compensations were more pronounced with the TB (IMPA, 1.92; P = 0.02), leading to greater overbite and overjet correction. Only the inclination of the maxillary incisors showed interaction with the growth pattern, with the TB horizontal growers experiencing more retroclination (U1-NA°. 3.620; P = 0.0067).

CONCLUSIONS

Both appliances produced similar modest AP skeletal changes that, together with dentoalveolar compensations, were able to correct the Class II malocclusion regardless of growth pattern.

Biomechanical effects of Teuscher activator in hyperdivergent Class II malocclusion treatment: A finite element analysis

Background

In orthodontic treatment, the combination of an activator with a headgear is commonly used in treatment of the hyperdivergent Class II malocclusion. However, the distribution of stresses transmitted to the maxilla by these appliances has been little studied. This study aimed to compare the biomechanical effects of stresses transmitted to the maxilla and teeth by a Teuscher activator (TA) for different lines of action of extraoral force, using finite element analysis.

Material and Methods

A tridimensional finite element model of the maxilla and teeth was created based on the true geometry of a human skull. The (TA) and the face bow were designed in 3D computer-aided design and fixed in the maxilla model. To study the effects of mechanical stress transmitted to the maxilla in the treatment of hyperdivergent Class II malocclusion with (TA) combined with extraoral forces, five different finite element models were used, considering the centers of resistance of the maxilla and dentition.

Results

The results showed that stresses increased progressively when the force line of action moved in posteroanterior direction. Von Mises equivalent stress was lower in Model 1 (0°) than in Model 5 (60°). In Models 1 (0°) and 2 (15°), molars suffered greater distal displacement and incisors showed extrusion. In Model 3 (30°), the force line of action promoted a distal displacement of molars and incisors. In Models 4 (45°) and 5 (60°), the whole maxillary anterior sector showed counterclockwise displacement.

Conclusions

Different force lines of action influence the intensity and distribution of orthodontic and orthopedic forces in the maxilla. The extraoral force's line of action used in Model 3 (30°) is the most compatible with the objectives of the hyperdivergent Class II malocclusion treatment in growing patients. Key words:Class II, Headgear, Early treatment, FEA.

Does Appliance Design Affect Treatment Outcomes of Class II Division 1 Malocclusion? A Two-Center Retrospective Study

Objectives

The purpose of this retrospective study was to compare the pre- and post-treatment values of patients treated with monoblock and twin-block appliances with the values of the skeletal Class I individuals.

Material and Methods

The initial lateral cephalometric radiographs of the pubertal untreated skeletal class I patients and cephalometric radiographs of 60 (30 monoblock, 30 twin-block) patients before and after the functional treatment were included in the study. Skeletal, dental, and soft tissue measurements were performed by a single researcher using Dolphin Imaging software version 11.95 (Dolphin Imaging, Chatsworth, CA, USA). Paired t-test was used for statistical evaluation and P < 0.05 was considered statistically significant.

Results

In both monoblock and twin-block groups, there was a statistically significant increase in the measurements of the lower jaw and the vertical direction values (sella nasion B point (SNB), pogonion nasion perpendicular, Y-axis, sella nasion-gonion gnathion, palatal-mandibular angle, anterior facial height, mandibular length P < 0.05); however, in the Twin-block group, the lower jaw was found to be displaced more forward (change for twin-block; SNB = 2.35, Wits appraisal = -4.77). The most measurements of the twin-block treated group were similar to the control group.

Conclusions

Both functional appliances have been identified to be useful in achieving treatment targets; however, with twin-block, results closer to ideal values are obtained.

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.

The biological basis of treating jaw discrepancies: An interplay of mechanical forces and skeletal configuration

Jaw discrepancies and malrelations affect a large proportion of the general population and their treatment is of utmost significance for individuals' health and quality of life. The aim of their therapy is the modification of aberrant jaw development mainly by targeting the growth potential of the mandibular condyle through its cartilage, and the architectural shape of alveolar bone through a suture type of structure, the periodontal ligament. This targeted treatment is achieved via external mechanical force application by using a wide variety of intraoral and extraoral appliances. Condylar cartilage and sutures exhibit a remarkable plasticity due to the mechano-responsiveness of the chondrocytes and the multipotent mesenchymal cells of the sutures. The tissues respond biologically and adapt to mechanical force application by a variety of signaling pathways and a final interplay between the proliferative activity and the differentiation status of the cells involved. These targeted therapeutic functional alterations within temporo-mandibular joint ultimately result in the enhancement or restriction of mandibular growth, while within the periodontal ligament lead to bone remodeling and change of its architectural structure. Depending on the form of the malrelation presented, the above treatment approaches, in conjunction or separately, lead to the total correction of jaw discrepancies and the achievement of facial harmony and function. Overall, the treatment of craniofacial and jaw anomalies can be seen as an interplay of mechanical forces and adaptations occurring within temporo-mandibular joint and alveolar bone. The aim of the present review is to present up-to-date knowledge on the mechano-biology behind jaw growth modification and alveolar bone remodeling. Furthermore, future molecular targeted therapeutic strategies are discussed aiming at the improvement of mechanically-driven chondrogenesis and osteogenesis.

Comparison of Activator-Headgear and Twin Block Treatment Approaches in Class II Division 1 Malocclusion

The purpose was to compare the treatment effects of functional appliances activator-headgear (AH) and Twin Block (TB) on skeletal, dental, and soft-tissue structures in class II division 1 malocclusion with normal growth changes in untreated subjects. The sample included 50 subjects (56% females) aged 8–13 years with class II division 1 malocclusion treated with either AH (n = 25) or TB (n = 25) appliances. Pre- and posttreatment lateral cephalograms were evaluated and compared to 50 untreated class II division 1 cases matched by age, gender, ANB angle, and skeletal maturity. A paired sample, independent samples tests and discriminant analysis were performed for intra- and intergroup analysis. Treatment with both appliances resulted in significant reduction of skeletal and soft-tissue facial convexity, the overjet, and the prominence of the upper lip in comparison to untreated individuals (p < 0.001). Retroclination of maxillary incisors and proclination of mandibular incisors were seen, the latter being significantly more evident in the TB group (p < 0.05). Increase of effective mandibular length was more pronounced in the TB group. In conclusion, both AH and TB appliances contributed successfully to the correction of class II division 1 malocclusion when compared to the untreated subjects with predominantly dentoalveolar changes.

The Effects of Functional Appliances on Female Patients with Skeletal Class II Malocclusion 6 Months after Menarche

AIM

To investigate the skeletal, dental, and soft tissue changes in girls with class II division 1 malocclusion after growth spurt peak under the effect of activator appliance.

MATERIALS AND METHODS

In this clinical trial study, 15 female patients, with skeletal class II and mandibular growth deficiency and at least 5 mm overjet, were randomly selected 6 months after their menarche. The mean of their ages at the beginning was 12.33 ± 0.81 years, and in the end it was 13.73 ± 0.79 years; the mean duration of treatment was 12.2 ± 3.18 months. Lateral, cephalometric radiographs were taken from all the patients before and after the treatment. Data were analyzed with Statistical Package for the Social Sciences (SPSS) 20 using paired t-test.

RESULTS

On an average, the ANB angle, the angle of the upper incisors with the S-N, facial convexity, and overjet decreased by 2.6° ± 0.9, 5.4° ± 0.8, 3.8° ± 3.4, and 5.6 ± 1.8 mm respectively. The SNB angle, the angle of the lower incisors with the N-B, the labiomental angle, the total length of the mandible, the lower anterior facial height, the lower lip distance, the first molar of the mandible, and the soft tissue pogonion to the vertical line from the S point increased by 2.8° ± 1.8, 3.4° ± 3, 14.7 ± 15, 3.7 ± 2.6, 2.1 ± 1.6, 6.3 ± 2.5, 4.4 ± 2.4, and 6 ± 3.3 mm respectively. All these figures were statistically significant (p = 0.000).

CONCLUSION

The functional appliance improved the dental-skeletal relations and the soft tissue profile of patients after the growth spurt peak of puberty in a group of Iranian girls, whereas dental changes were more than skeletal ones.

CLINICAL SIGNIFICANCE

Functional appliances can be used for correction of skeletal class II malocclusion 6 months after menarche in girls.

Dental and skeletal effects of combined headgear used alone or in association with rapid maxillary expansion

OBJECTIVE

The aim of this study was to assess the effects of combined headgear used alone or in association with rapid maxillary expansion, as the first step for Class II malocclusion treatment.

METHODS

The sample comprised 61 patients divided into three groups: Group 1, combined headgear (CH); Group 2, CH + rapid maxillary expansion (CH + RME); and Group 3, control (CG). In Group 1, patients were treated with combined headgear until Class I molar relationship was achieved. In Group 2, the protocol for headgear was the same; however, patients were previously subject to rapid maxillary expansion.

RESULTS

Results showed distal displacement of maxillary molars for both experimental groups (p < 0.001), with distal tipping only in Group 1 (CH) (p < 0.001). There was restriction of forward maxillary growth in Group 2 (CH + RME) (p < 0.05) and clockwise rotation of the maxilla in Group 1 (CH) (p < 0.05).

CONCLUSION

Based on the results, it is possible to suggest that treatment with both protocols was efficient; however, results were more significant for Group 2 (CH + RME) with less side effects.

Long-term stability of dentoalveolar and skeletal changes after activator-headgear treatment

The aim of this study was to analyze the long-term stability of combined activator-headgear treatment on skeletal and dental structures in Class II patients. The material comprised 26 subjects, 10 girls and 16 boys. All had a molar Class II relationship, overjet > or =6 mm, and overbite > or =5 mm. They were treated in one practice with combined activator and headgear appliances. Lateral cephalometric radiographs and dental study casts were taken before treatment (T0, mean age 11.9 years), at the end of activator-headgear treatment (T1, mean age 15.9 years), and 12-15 years out of retention (T2, mean age 28.6 years). Nineteen cephalometric and nine dental cast variables were evaluated using a paired sample t-test between T0-T1, T1-T2, and T0-T2. At T1, the majority of the cephalometric measurements showed statistically significant changes. ANB was significantly reduced by 2.3 degrees due to a significant increase in SNB, but only small changes were observed in SNA. The interincisal angle increased as a result of significant retroclination of both maxillary and mandibular incisors. All patients achieved a Class I molar relationship and a significant reduction in overjet and overbite. At T2, the results showed only slight relapse from T1. However, the relapse did not compromise the significant improvement in almost all the cephalometric and dental variables. Combined activator-headgear treatment improved the skeletal and dental conditions and the results remained stable in the long term.