Effects of Class II elastics during growth on the functional occlusal plane according to skeletal pattern and extraction vs nonextraction

ABSTRACT Objectives To investigate the effect of Class II intermaxillary elastics on the functional occlusal plane (FOP) of growing patients. Materials and Methods A total of 50 participants aged 11 to 16 years were selected from a university clinic archive >1-year after treatment and after undergoing 6 months of Class II elastic wear, taking pretreatment (T0) and posttreatment (T1) lateral cephalometric radiographs, and consenting to participate at recall (T2). Participants were divided into 3 groups according to skeletal pattern or into 2 groups according to treatment with extraction (E) or nonextraction (NE). Angular changes of FOP relative to the Sella-Nasion (SN), mandibular plane (MP), and Frankfort horizontal (FH) were compared within and between groups. Results A statistically significant reduction of FOP-SN/FH, but not of FOP-MP, was found from T0–T1–T2 when all patients were grouped together. FOP-SN/MP/FH was significantly the largest in the patients with a hyperdivergent skeletal pattern, but lowest in the patients with a hypodivergent skeletal pattern at T0, T1, and T2 (P < .032). FOP-MP at T0–T2 was statistically larger in group E than in group NE (P < .02). No differences were found for FOP changes (change before treatment minus after treatment and change after treatment minus 1 year after treatment) between different skeletal patterns (P > .433) and treatment groups (P > .193). Conclusions Use of Class II elastics during the growth period was not found to show adverse effects on FOP rotation. Neither skeletal pattern nor treatment modality differed in the response to Class II elastics with regard to FOP changes. Individual patient growth pattern must be taken into consideration when treatment planning the use of Class II elastics. Orthodontists should take into account individual skeletal and growth patterns while using Class II elastics.

The efficiency of mandibular mini-implants in reducing adverse effects of class II elastics in adolescent female patients: a single blinded, randomized controlled trial

Background Excessive proclination of lower incisors and other undesirable consequences usually result from the use of class II elastics during orthodontic treatment. The purpose of this study was to attempt to limit the adverse effects of class II elastics by the use of mini implants placed in the mandibular arch in adolescent class II female patients. Methods The sample comprised 28 patients, (a mean age of 15.66 ± 2 years for intervention group and 15.1 ± 2.2 years for conventional group) with one-fourth or one-half unit class II canine relationship. The sample was divided into two equal groups. Randomization was carried out by a computer sequence generator with a 1:1 allocation ratio. In the intervention group, the mini implants were inserted between the lower second premolar and first molar, while the conventional group underwent regular class II elastics therapy. The active elastics treatment time was 8 months for both groups. Results were assessed by measurements from pre- and post-elastics lateral cephalometric radiographs. Results The change in L1 inclination (0.97 ± 0.92°) and L1 AP position (0.31 ± 0.63 mm) did not show a statistically significant difference between the two groups, but a statistically significant difference was found in the U1 retroclination (5.23 ± 1.92°) and U1 distal movement (4.05 ± 1.4 mm) [P ˂ 0.001] and [P ˂ 0.05] respectively in favor of the intervention group. Conclusion Mini-implants in conjunction with class II elastics had no skeletal effect, mainly dentoalveolar and it did not prevent the proclination of lower incisors. There was more distal movement in the upper incisors in the skeletal anchorage group which helped in enhancing the camouflaging of class II malocclusion. Trial registration Trial registered “FUE.REC (10)/10-2018” at the FUE registration council for clinical trials/IOP Orthodontic Program October 2018.

Fixed Functional Appliances

Considering the large number of fixed functional appliances, choosing the best device for your patient is not an easy task. To describe the development of fixed functional appliances as well as our 20-year experience working with them. Fixed functional appliances are grouped into flexible, rigid and hybrid. They are different appliances, whose action is described here. Four clinical cases will be reported with a view in illustrating the different appliances. Rigid fixed functional appliances provide better skeletal results than flexible and hybrid ones. Flexible and hybrid appliances have similar effects to those produced by class II elastics. They ultimately correct class II with dentoalveolar changes. From a biomechanical standpoint, fixed functional appliances are more recommended to treat class II in dolichofacial patients, in comparison to class II elastics. The electromyographic (EMG) activity of masticatory muscles was monitored longitudinally with chronically implanted EMG electrodes to determine whether functional appliances produce a change in postural EMG activity of the muscles. Pre-appliance and post-appliance EMG levels in four experiments that had been fitted with functional appliances were compared against the background of EMG levels in controls without appliances. The insertion of two types of functional appliance to induce mandibular protrusion was associated with a decrease in postural EMG activity of the superior and inferior heads of the lateral pterygoid, superficial masseter, and anterior digastric muscles; the decrease in the first three muscles was statistically significant. This decreased postural EMG activity persisted for approximately 6 weeks, with a gradual return towards pre-appliance levels during a subsequent 6-week period of observation. Progressive mandibular advancement of 1.5 to 2 mm every 10 to 15 days did not prevent the decrease in postural EMG activity. KEY WORDS Orthodontics, Class II Malocclusion, Fixed Functional Appliance.

Three-dimensional mandibular changes associated with Class II elastics and extractions treatment in adult patients

Backgroud: The apllication of Class II elastic can induce the rotation of mandible and condylar response. The purpose of this study was to assess the positional and morphological alterations of mandible after orthodontic treatment with Class II elastic by using of 3-dimensional superimposition of pretreatment (T1), posttreatment (T2) and after retention (T3) CBCT data. Methods: With sequential 3D superimpositions that combined cranial base superimpositions with regional mandibular superimpositions, the virtual reference mandibles were placed to distinguish morphological changes from positional changes. The morphological changes and positional changes of mandibles were measured by comparing multiple combinations of reference and original mandibles respectively, and the corresponding paired t test was performed using SPSS (IBM SPSS version 23). Results: During orthodontic treatment (T1-T2), the mandibular molars were extruded, and the condyles were revealed apparent adaptive remodeling and upward/backward displacements. The mandible rotated backwardly and drifted backwardly/downwardly. The condylar growth and displacements were significantly different. The condylar growth did not induce isometric displacements and the forward rotation was restricted. Two years after retention (T2-T3), continuous morphological and positional changes occurred. The condylar remodeling and forward/downward displacements induced forward mandibular rotation and neutralized the backward rotation during treatment period (T1-T2). The overall positional changes (T1-T3) were translations with slight rotation. Statistically significant differences were found between the treatment and overall variables regarding the 3D rotation, condylar displacement, Pog displacement. And with the continuous morphological and positional changes, the condyle moved back to the initial position after the retention stage.Conclusion: Conclusions: the sequential 3D superimposition method can produce the reference mandibles and distinguish the morphological changes from positional alterations. The class II elastics induced mandibular complex changes including condylar adaptive remodeling and 3D rotation and translation. The condyles morphologically adapted to resist the rotation effects of Class II elastic.

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.

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

ABSTRACT 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.

Tratamento da Classe II com Invisalign

Complete correction of Class II malocclusion in an adult patient is not an easy task. In a case with large skeletal discrepancy, orthognathic surgery is the treatment of choice. However, in case of slight or borderline discrepancy, other treatment options are available, such as tooth extractions and miniscrews. Intermediate cases can also be treated with Class II correctors and elastics. This clinical report presents the orthodontic treatment of a 25-year-old female patient with Class II malocclusion. Clinically, the maxilla was well positioned, and the mandible was slightly retruded. The patient presented vestibularized upper incisors, well-positioned lower incisors and opted for a more aesthetically attractive orthodontic appliance. The treatment plan included teeth leveling and aligning in both arches, Class II correction, establishment of Class I molar and canine relationships, correction of overjet and overbite, midline correction, and improvement of facial and dental aesthetics. The orthodontic treatment consisted of removable Invisalign aligners and Class II elastics.

O tratamento compensatório da Classe II e mordida aberta esquelética com bráquetes autoligados – relato de caso

Class II malocclusion can be dental, skeletal or a combination of both and is present in approximately 60% of patients seeking corrective orthodontic treatment. Facial Pattern II patient often needs dental decompensation associated with orthognathic surgery to correct the bone bases. With the increasing use of the self-ligating system in Orthodontics, the number of patients who were indicated for extraction as part of their treatment has decreased considerably. Compensatory treatment aims to minimize skeletal deformities with dento-alveolar movements. This paper reports through a clinical case, the efficiency of the self-ligating system in Pattern II patient without extractions with expansionist therapeutic goals in association with the use of Class II elastics. Due to the patient’s rejection of orthognathic surgery, the compensatory treatment resulted in the camouflage of the skeletal discrepancies through the self-ligating system. Despite the surgical indication, the compensatory treatment presented significant dental movements, resulting in treatment success with considerable facial improvement.