Effects of intermaxillary elastic traction on orthodontic tooth movement

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

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.

Using orthodontic elastic traction during the active period of distraction osteogenesis to increase the effective vertical extension of hemifacial microsomia patients: A multi-center randomized clinical trial

In this study, the aim was to assess whether using elastic traction during the active period of distraction osteogenesis could effectively increase the vertical extension. Patients with Pruzansky-Kaban Type II mandibular deformity were recruited and randomly assigned into Elastic traction + Distraction Osteogenesis group or Distraction Osteogenesis group, respectively. During the active period, the experimental group received orthodontic elastic traction 3 days after distraction osteogenesis implantation, while the control group received no treatment. All the participants underwent computed tomography (CT) examination before surgery, at the end of the active period, 6 months and 2 years after distraction osteogenesis tractor implantation. The primary outcome was the effective vertical extension rate of the mandible from the baseline to the end of the active period after operations, and there were 7 secondary outcomes used. 70 patients were included. The effective vertical extension rates were 85.021% ± 7.432% (mean ± SD) and 68.811% ± 9.510% (mean ± SD) in the experimental and control groups, respectively (P = 0.001). The average distances between the lower middle incisor point to the sagittal plane at the end of the active period were 2.485 ± 1.411 mm and 3.938 ± 2.293 mm in the experimental and control groups, respectively (P = 0.026). At the end of the active period of distraction osteogenesis, the average values of the mandibular occlusal plane canting were -4.887 ± 3.126 mm and -0.177 ± 4.029 mm in the experimental and control groups, respectively (P = 0.026). Elastic traction-assisted distraction osteogenesis could improve traction efficiency and facial symmetry.

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.

Therapeutic outcomes in the treatment of unilateral glenoid fossa fractures using intermaxillary elastic traction

INTRODUCTION

This study aimed to evaluate the therapeutic outcomes of intermaxillary elastic traction in the treatment of unilateral glenoid fossa fractures.

METHODS

Five patients with traumatic unilateral glenoid fossa fractures were treated with intermaxillary elastic traction at the Sun Yat-Sen University Hospital of Stomatology during a 5-year period from 2006 to 2011. Pantomography and Schüller position radiographs were obtained at days 7, 28, and 90 to monitor glenoid fossa fracture healing. Removal of the intermaxillary elastic traction and the arch bar splint occurred at day 90, and the patients were advised to initiate mouth-opening exercises.

RESULTS

Schüller position radiographs revealed a 100% reduction rate of the glenoid fossa fracture for all patients; morphologies of the glenoid fossa and mandibular condyle were normal. Follow-up ranged from 6 months to 2 years. The occlusal relationship (degree of mouth opening) was excellent in all cases. Patient recoveries were uneventful; no complications occurred such as pain, snapping, or limitations of mouth opening. Average mouth opening was measured at 3.6 cm at the last follow-up.

CONCLUSIONS

Intermaxillary elastic traction is an effective, simple, and feasible method in the treatment of a glenoid fossa fracture. Accurate reduction and stable fixation may be achieved without significant complications.

Therapeutic changes in the occlusal plane inclination using intermaxillary elastics

AIM

The goal of the study was the evaluation of opposing intermaxillary elastics concerning potential change in the occlusal plane inclination relative to relevant vertical structures.

PATIENTS AND METHODS

Thirty-two late adolescent, skeletally homogeneous patients (basal-sagittal relationship: neutral; basal-vertical: neutral; no transverse discrepancies) were treated either with Class II (group A; n=16) or Class III elastics (group B; n=16) for unimaxillary space closure. Mean wearing times were 26 (A) and 24 months (B). Cephalograms at the start and end of treatment were analyzed. Changes in the inclination of the occlusal plane (BOP according to Downs) relative to three reference planes (NL, ML, NSL), as well as changes in the reference planes toward each other underwent statistical testing with a two-tailed Student t-test.

RESULTS

The occlusal plane shift differed significantly when opposing elastics were applied (p<0.001). The induced shift with Class II elastics (A) was clockwise, while Class III elastics were counterclockwise (A: NL-BOP: +0.9°, ML-BOP: -2.1°; B: NL-BOP: -3.1°, ML-BOP: +3°). Reference planes NL and ML underwent insignificant change towards one another (A: -1.2°; B: -0.1°). The maxillo-mandibular complex itself rotated counterclockwise toward the anterior cranial base (NSL) (A: NL-NSL: -0.8°, ML-NSL: -2°; B: NL-NSL: -0.6°, ML-NSL: -0.7°). Thus, almost no change in BOP (+0.1°, n.s.) relative to NSL was detected when Class II elastics were applied, whereas the use of Class III elastics led to a significant counterclockwise rotation (-3.7°, p<0.001)

CONCLUSION

Class III elastics enhance the physiologic inclination of the maxillo-mandibular complex at the level of the occlusal plane, whereas Class II elastics oppose or even eliminate the process.

Class III subdivision malocclusion corrected with asymmetric intermaxillary elastics

Correcting a Class III subdivision malocclusion is usually a challenge for an orthodontist, especially if the patient's profile does not allow for any extractions. One treatment option is to use asymmetric intermaxillary elastics to correct the unilateral anteroposterior discrepancy. However, the success of this method depends on the individual response of each patient and his or her compliance in using the elastics. The objectives of this article were to present a successful treatment of a Class III subdivision patient with this approach and to illustrate and discuss the dentoskeletal changes that contributed to the correction.

Orthognathic treatment for a patient with Class III malocclusion and surgically restricted mandible

This case report describes the orthodontic-surgical treatment of an adult with Down syndrome and a Class III skeletal malocclusion with posterior open bite, horizontal facial pattern, missing mandibular posterior teeth, and surgical restriction of the mandible.