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

Assessment of the condylar response of two differently anchored fixed functional appliances in class II malocclusion in young adult orthodontic patients: A randomized clinical trial

OBJECTIVE

Measuring the condylar volume changes after treatment with skeletally anchored type IV Herbst appliance vs. Twin Force Bite Corrector (TFBC) in class II malocclusion in young adult patients.

MATERIALS AND METHODS

Twenty class II malocclusion participants were randomly involved in our randomized clinical study. They are divided equally into two groups: group I (10 patients with an age range of 16 to 18 years and a mean age of (17.15 ± 0.62) (five males and five females) with a mean Angle formed between (A) point and (Nasion) point and (B) point, to determine anteroposterior relation between maxilla and mandible (ANB) of 6.20 (1.03) and a mean mandibular length of 106.1 (1.7), who were treated by a skeletally anchored type IV Herbst appliance, supported at the mandible by two mini-plates fixed bilaterally at the mandibular symphysis; group II (10 patients with an age range of 15 to 18 years and a mean age of (16.85 ± 0.33) (six males and four females) with a mean ANB of 6.80 (0.89) and a mean mandibular length of 107.3 (2.36), who were treated by a TFBC that was installed just mesial to the tube of the maxillary first permanent molar and distal to the bracket of the lower canine for 4 months. According to the Index of Orthognathic Functional Treatment Need (IOFTN) index, the participants in both groups have grade 4 (great need for treatment) as they have excessive overjet (6-9 mm). Cone-beam computed tomography (CBCT) was taken just before installing fixed functional appliances and after the removal. The condylar volume was measured using Dolphin software. Parametric measurements were performed by the independent t-test, while non-parametric variables (percent change) were compared by the Mann-Whitney U-test.

RESULTS

On the right side, the Herbst group recorded a percent increase (median = 1.23%), while TFBC recorded a median percent decrease (-7.85%). This change is statistically significant (P = 0.008).

CONCLUSIONS

The difference in the condylar volume was significantly higher with the mini-plate anchored Herbst appliance than with the dentally anchored TFBC group.

Clinical finite element analysis of mandibular displacement model treated with Twin-block appliance

INTRODUCTION

The mechanical distribution of the mandible is an important factor that affects functional orthosis during Twin-block (TB) appliance correction. Changes in the mandible before and after TB appliance correction are also key factors in maintaining the therapeutic effect. Finite element analysis, a powerful numerical, analytical tool, is widely used to predict the stress and strain distribution of the craniofacial bone that orthodontics generates.

METHODS

The sample was a 14-year-old male patient with Class II malocclusion during growth. A cone-beam computed tomography scan was undertaken at pretreatment and posttreatment. In the Finite element analysis of the pretreatment model, the remote displacement model of the mandible was established with the sella point as the center. A mandibular model under TB appliance loading was established. Its mandibular displacement and von Mises stress were compared before and after loading. Three-dimensional registration was conducted on the pretreatment and posttreatment models to measure the sagittal displacement of the centrosome.

RESULTS

The force on the mandible occurred mainly in the condyle neck and medial mandible after the TB appliance moved the mandible. After displacement, the posterior upper margin of the condyle was farther away from the articular fossa. Three-dimensional registration results showed that new bone had formed behind and above the condyle after TB appliance treatment.

CONCLUSION

The TB appliance provides additional advantages in treating skeletal Class II malocclusions by helping to reduce the burden on the temporomandibular joint and promoting the adaptive reconstruction of the mandible.

Twin-block and mandibular anterior repositioning appliances effects in Class II malocclusion correction

INTRODUCTION

The objective of this study was to compare the cephalometric changes in Class II Division 1 malocclusion patients treated with the Twin-block (TB) and the mandibular anterior repositioning appliance (MARA).

METHODS

This retrospective study was performed with 132 lateral cephalograms of patients with Class II malocclusion divided into 3 groups: a TB group comprised 21 patients with mean initial and final ages of 10.59 and 11.97 years, respectively, treated for a mean period of 1.38 years; a MARA group comprised 21 patients with mean initial and final ages of 11.98 and 13.20 years, respectively, treated for a mean period of 1.22 years; and a control group included 24 subjects with untreated Class II malocclusion with mean initial and final ages of 10.55 and 12.01 years, respectively, observed for a mean period of 1.46 years. Cephalometric intergroup comparisons regarding the treatment changes (T2 - T1) were performed with the analysis of covariance, followed by Tukey tests.

RESULTS

Both appliances demonstrated significant restriction of the maxilla and improvement of the maxillomandibular relationship. The MARA produced a significantly greater amount of labial tipping and protrusion of the mandibular incisors than the other groups. The TB showed significant extrusion of the mandibular incisors and molars compared with MARA and control, respectively. Both treated groups reduced the overjet and overbite. The MARA presented a significantly greater reduction in the molar relationship than the other groups.

CONCLUSIONS

The appliances showed a headgear effect on the maxilla and effectively changed Class II cephalometric parameters through a combination of skeletal and dentoalveolar effects. TB showed a greater increase in LAFH. MARA promoted greater labial tipping and protrusion of the mandibular incisors.

Comparison of the effects of removable functional appliance therapy applied in pubertal and postpubertal periods: A retrospective cephalometric and fractal analyses study

INTRODUCTION

In this study, we compared the effects of functional treatment with Twin-block appliance on the bony architectures of the maxilla and mandible by fractal dimension (FD) analysis, and the skeletal and dentoalveolar effects by cephalometric analysis, in pubertal and postpubertal patients with Class II malocclusion.

METHODS

This study comprised 60 patients who underwent Twin-block treatment. Group 1 consisted of 30 patients in the pubertal period (6 boys and 24 girls; mean age 12.27 ± 1.35 years), whereas group 2 consisted of 30 patients in the postpubertal period (6 boys and 24 girls; mean age 13.73 ± 1.51 years). FD analysis was performed on the patients before and after Twin-block panoramic and lateral cephalometric radiographs. Cephalometric analysis was also conducted. Paired and Student t tests were used to compare the parametric data, and Wilcoxon signed rank and Mann-Whitney U tests were conducted to compare the nonparametric data.

RESULTS

SNB, Pg-N, N-Me, ANS-Me, IMPA, L1/NB, Co-Gn, Go-Gn, S-Go, Co-Go, and Go-Me significantly increased in both groups after treatment. FD values of tuber, condyle, and molar regions significantly decreased in group 1, whereas no significant differences were observed in group 2 after treatment.

CONCLUSIONS

In the pubertal period, the Twin-block appliance resulted in skeletal correction by causing bone remodeling and reshaping in both jaws along with the dentoalveolar correction. In the postpubertal period, Twin-block had no significant effect on the bone trabecular arrangement in the investigated areas but produced cephalometric improvement to a certain extent with lower skeletal and higher dental impact.

MANAGEMENT OF CLASS II MALOCCLUSION USING TWIN FORCE BITE CORRECTOR

Class II malocclusion is one of the most commonly occurring conditions, and the component mostly involved is mandibular retrognathism. The treatment modalities include both removable and fixed appliances. The advantage of fixed functional appliances is that it is not dependent on patient compliance. Various fixed functional appliances are available such as rigid, flexible, and hybrid. The present case series discusses a hybrid type of fixed functional appliance, i.e. Twin Force Bite Corrector appliance in three cases: A 15‑year‑old female patient with Class II malocclusion due to mandibular retrognathism, a 14‑year‑old male patient with Class II malocclusion due to mandibular retrognathism, and a 14‑year‑old female patient with Class II malocclusion due to mandibular retrognathism. The effects produced by this appliance are similar to the conventional fixed functional appliances such as Forsus, Herbst, and also it has a distinct advantage of quick chair-side fabrication and simple design.

Comparison of AdvanSync2® and Twin Block Appliances in Treatment of Class II Malocclusion With Retrognathic Mandible—An Observational Retrospective Study

Objectives:

To evaluate the treatment outcomes between Twin Block and AdvanSync2® appliances by comparing the skeletal, dentoalveolar, and soft tissue changes.

Materials and Methods:

Radiographic data of 20 patients were retrospectively analyzed. Data were selected from patients in their skeletal growth spurt as evaluated by the cervical vertebral maturation method (CVMI 2, 3, and 4), with class II malocclusion characterized with retrognathic mandible (ANB > 4°, SNB < 77°, FMA = 25 ± 5°, overjet > 5 mm). There were 10 patients in each group that underwent orthodontic correction for class II malocclusion: either using Twin Block or AdvanSync2®. Independent t test and Paired t test and chi-square tests were used for the data analysis. The level of statistical significance was set at P value ≤.05.

Results:

The chronological and skeletal age were similar in both the groups. Records were taken for the functional treatment with mean treatment span of 8 ± 1 month. Changes in SNB (group I = 1.59°, group II = 3.11°) ( P < .01), Co-Gn (group I = 2.89 mm, group II = 5.34 mm), and U1-L1° (group I = −1.51°, group II = 2.97°) showed statistically different outcome between the groups, when the pre-post data were studied. Rest of the variables—cranial base, maxillary skeletal, mandibular skeletal, intermaxillary, vertical skeletal, maxillary dentoalveolar, mandibular dentoalveolar, and soft tissue—showed similar outcome ( P > .05).

Conclusion:

Both appliances lead to desirable outcomes in the correction of class II malocclusion. AdvanSync2® resulted in inducing more of changes in SNB and effective mandibular length as compared to Twin Block. Overjet and molar relation improved significantly with both the appliances. Both the appliances resulted in similar skeletal, dentoalveolar, and soft tissue changes.

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.

Soft tissue profile changes in Angle class II patients treated with Twin Force or intermaxillary elastics-a comparison

PROPOSITION

This study aimed to compare soft tissue profile changes in Angle class II malocclusion patients treated with a Twin Force appliance (Ortho Organizers, Inc., Carlsbad, CA, USA) or class II elastics.

METHODS

The sample comprised 47 class II malocclusion patients treated orthodontically without extractions, divided into two groups. Group 1 (Twin Force): 25 patients were treated with the Twin Force, with initial and final mean ages of 17.91 and 20.45 years, respectively, and mean treatment time of 2.53 years. Group 2 (elastics): 22 patients were treated with class II elastics, with initial and final mean age of 15.87 and 18.63 years, respectively, and mean treatment time of 2.75 years. The lateral cephalograms were evaluated at the initial and final stages. Intragroup comparisons were performed with dependent t-tests and intergroup comparisons were performed with independent t-tests.

RESULTS

Treatment-related changes in the Twin Force group included reduction of facial convexity, retrusion of the upper lip, increase of the H‑Nose distance, and decrease in Sn‑H distance, indicating improvement in facial profile. In the elastics group, treatment resulted in an increase in nasolabial angle, retrusion of the upper lip, increase of the H‑Nose distance, and decrease in Sn‑H distance, indicating improvement in facial profile. The Twin Force group showed a greater reduction of the facial convexity with treatment than the elastics group.

CONCLUSIONS

Class II patients treated with the Twin Force appliance showed greater reduction in facial convexity than patients treated with class II elastics. The other soft tissue changes were similar for both groups.

Treatment Effects of the Herbst Appliance in Class II Malocclusion Patients after the Growth Peak

OBJECTIVE

 The aim of this study was to evaluate dentoskeletal changes in the treatment of Class II malocclusion with the Herbst Cantilever Bite Jumper (CBJ) appliance, associated with multibracket appliances after the growth peak, at pretreatment.

MATERIALS AND METHODS

 A sample of 37 individuals was divided into two groups: the experimental group comprised 16 patients treated consecutively for a mean period of 2.52 years with the Herbst CBJ appliance associated with multibracket appliances. A total of 21 subjects (10 males and 11 females) with Class II malocclusion and mean age at T1 of 16.08 years were followed for a mean period of 2.12 years composed the control group. Comparisons between the two groups were performed using initial and final lateral cephalograms. Comparisons between experimental and control groups at pretreatment and of the treatment changes were performed by Mann-Whitney or independent t-tests.

RESULTS

 Experimental group exhibited a significantly greater labial inclination of the mandibular incisors in comparison to the control group. Additionally, significantly greater corrections in overbite, overjet, and molar relationship were observed in the experimental than in the control groups.

CONCLUSION

 The effects of the Herbst CBJ appliance, associated with fixed appliances after the growth peak in Class II malocclusion treatment are correction in molar relationship toward a Class I relationship, decrease of the overjet, decrease of the overbite, and mandibular incisors labial inclination.

Long-term stability of Class II treatment with the Jasper jumper appliance

INTRODUCTION

Treatment of Class II Division 1 malocclusion with orthopedic devices combined with fixed orthodontic appliances has shown excellent results when used in growing patients. We aimed to evaluate the long-term stability of the cephalometric changes obtained during Class II malocclusion correction with the Jasper jumper associated with fixed appliances.

METHODS

The treatment group comprised 24 patients who were evaluated at 3 stages: pretreatment, posttreatment, and long-term posttreatment. The control group comprised 15 subjects with normal occlusion. Intratreatment group comparisons among the 3 stages were performed with repeated measures analysis of variance, followed by Tukey tests. Intergroup comparisons of posttreatment changes and normal growth changes of the treatment group were performed with t tests.

RESULTS

Apical base relationship, maxillary incisor anteroposterior position, and overjet demonstrated significant relapses in relation to the control group.

CONCLUSIONS

Most dentoalveolar changes obtained with the Jasper jumper followed by fixed appliances during treatment remained stable in the long term. However, apical base relationship, maxillary incisor anteroposterior position, and overjet demonstrated significant relapses in relation to the control group. Therefore, active retention time should be increased in the posttreatment period.

Stress distribution in maxillary first molar periodontium using straight pull headgear with vertical and horizontal tubes: A finite element analysis

BACKGROUND

One of the most effective ways for distal movement of molars to treat Class II malocclusion is using extraoral force through a headgear device. The purpose of this study was the comparison of stress distribution in maxillary first molar periodontium using straight pull headgear in vertical and horizontal tubes through finite element method.

MATERIALS AND METHODS

Based on the real geometry model, a basic model of the first molar and maxillary bone was obtained using three-dimensional imaging of the skull. After the geometric modeling of periodontium components through CATIA software and the definition of mechanical properties and element classification, a force of 150 g for each headgear was defined in ABAQUS software. Consequently, Von Mises and Principal stresses were evaluated. The statistical analysis was performed using T-paired and Wilcoxon nonparametric tests.

RESULTS

Extension of areas with Von Mises and Principal stresses utilizing straight pull headgear with a vertical tube was not different from that of using a horizontal tube, but the numerical value of the Von Mises stress in the vertical tube was significantly reduced (P < 0/05). On the other hand, the difference of the principal stress between both tubes was not significant (P > 0/05).

CONCLUSION

Based on the results, when force applied to the straight pull headgear with a vertical tube, Von Mises stress was reduced significantly in comparison with the horizontal tube. Therefore, to correct the mesiolingual movement of the maxillary first molar, vertical headgear tube is recommended.

En-masse protraction of mandibular posterior teeth into missing mandibular lateral incisor spaces using a fixed functional appliance

Protraction of mandibular posterior teeth requiring absolute anchorage has always been a challenge, especially when the space is located in the anterior region, since more teeth must be protracted. Traditionally, skeletal anchorage devices have been used for anchorage reinforcement during protraction. However, drawbacks such as requirement of a surgical step, inability to tolerate heavy forces, and patient willingness to undergo such surgical procedures can be limiting factors. Additionally, the mechanics involved can sometimes create undesirable side effects, thereby limiting their application in such situations. This report describes the use of a fixed functional appliance as an anchorage-reinforcement device for en-masse protraction of mandibular posterior teeth into a missing lateral incisor space.

Class II, Division 1 Angle malocclusion with severe proclination of maxillary incisors

Protrusion of maxillary incisors is a common complaint among patients seeking orthodontic treatment. This report addresses the correction of Class II Angle malocclusion with excessively bucally proclined maxillary incisors, in an adolescent female patient, through the use of extraoral and fixed appliances. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO) as part of the requirements for obtaining the title of certified by the BBO.

Treatment effects of skeletally anchored Forsus FRD EZ and Herbst appliances: A retrospective clinical study

OBJECTIVE

To evaluate the skeletal, dentoalveolar, and soft tissue effects of the Forsus FRD appliance with miniplate anchorage inserted in the mandibular symphyses and to compare the findings with a well-matched control group treated with a Herbst appliance for the correction of a skeletal Class II malocclusion due to mandibular retrusion.

MATERIALS AND METHODS

The sample consisted of 32 Class II subjects divided into two groups. Group I consisted of 16 patients (10 females and 6 males; mean age, 13.20 ± 1.33 years) treated using the Forsus FRD EZ appliance with miniplate anchorage inserted in the mandibular symphyses. Group II consisted of 16 patients (9 females and 7 males; mean age, 13.56 ± 1.27 years) treated using the Herbst appliance. Seventeen linear and 10 angular measurements were performed to evaluate and compare the skeletal, dentoalveolar, and soft tissue effects of the appliances using paired and Student's t-tests.

RESULTS

Both appliances were effective in correcting skeletal class II malocclusion and showed similar skeletal and soft tissue changes. The maxillary incisor was statistically significantly more retruded in the skeletally anchored Forsus FRD group (P < .01). The mandibular incisor was retruded in the skeletally anchored Forsus FRD group (-4.09° ± 5.12°), while it was protruded in the Herbst group (7.50° ± 3.98°) (P < .001).

CONCLUSION

Although both appliances were successful in correcting the skeletal Class II malocclusion, the skeletally anchored Forsus FRD EZ appliance did so without protruding the mandibular incisors.

Long-term surgical versus functional Class II correction: a comparison of identical twins

The purpose of this twin case comparison was to assess the short- and long-term effects of nonsurgical treatment vs orthognathic surgical treatment for Class II correction. Two identical twins (age 13 years 3 months) were treated for Class II correction where one patient was treated nonsurgically using a fixed functional appliance, while the other was treated using orthognathic mandibular advancement surgery. The patients were recalled and evaluated 5 years in retention. Comparing changes in the short and long term, surgical treatment led to superior skeletal results compared to the nonsurgical twin. However, the soft tissue profile was remarkably similar for both patients suggesting that soft tissue profile changes may not necessarily follow similar changes in the bony skeletal structures.

Treatment of a skeletal Class II malocclusion using fixed functional appliance with miniplate anchorage

Based on our literature search, we found that the use of miniplate anchorage with Forsus fatigue-resistance device (FRD) has not yet been reported. Therefore, the aim of the present case report was to present the treatment of a patient with skeletal Class II malocclusion with mandibular retrusion using Forsus FRD with miniplate anchorage. Fixed appliances with 0.022-inch slots were attached to the maxillary teeth and after 8 months of the leveling and alignment of the upper arch, 0.019 × 0.025-inch stainless steel archwire was inserted and cinched back. Two weeks after the placement of the miniplates bilaterally at the symphysis of the mandible, Forsus FRD was adjusted to the miniplates with a 35-mm length of rod chosen. Nine months after the skeletal anchored Forsus worn, Class I canine and molar relations were achieved and overjet was eliminated.