Treatment of Skeletal Class III Malocclusion Using Orthodontic Removable Traction Appliance

Dentoskeletal Effects of The Orthodontic Removable Traction Appliance in The Treatment of Skeletal Class III Malocclusion: A Randomized Controlled Trial

This experimental study aims to evaluate the efficiency of the orthodontic removable traction appliance in the treatment of skeletal class III malocclusion. The study sample will consist of 44 patients with skeletal class III malocclusion. The sample will be allocated randomly into two groups: experimental group and control group. The dentoskeletal changes will be assessed by using lateral cephalometric radiographs before treatment and after obtaining 3mm positive overjet.

Treatment of class III malocclusion is a major challenge in orthodontic contemporary practice, Several appliance have suggested for the treatment of class III malocclusion, such as the facial mask and chin cup. Despite of the efficiency of this extraoral appliance, its external appearance and its big size reduce patients' cooperation which decrease its clinical effects. Another Class III treatment modality is the Orthodontic Removable Traction Appliance (ORTA). It is a removable appliance that can be used in conjunction with rapid palatal expansion or fixed appliances, It was developed in the 1980's by Dr. David Musich who developed this appliance in order to overcome issues of compliance that Dr. Musich experienced with use of the protraction facemask. There is only one study that evaluated this appliance which is a retrospective study compared the treatment effects of the ORTA and protraction facemask in treatment of Class III malocclusions. However, this study has a lot of limitations which made it difficult to accurately evaluate the efficiency of this device. The aim of this study is studying the dentoskeletal changes that result from treatment by this device, by comparing them to the changes in matched untreated group,by studying the cephalometric x-rays.

Patients in this group will be treated using the orthodontic removable traction appliance (vacuum plate with two hooks between lateral incisor and canine in each side). An rapid maxillary expander will be applied to disarticulate maxillary sutures to allow more efficient forward protraction of the maxilla. Class III elastic traction from upper first molar to the hook in both side. This appliance will be used full-time with Class III elastics (6- to 8-ounce) traction.

Vacuum plate with two hooks between lateral incisor and canine in each side will be applied on the lower arch.

Rapid maxillary expander will be applied in the maxilla to disarticulate maxillary sutures to allow more efficient forward protraction of the maxilla.

The change of the ANB angle before and after using the Orthodontic Removable Traction Appliance compared with this of the control group will be evaluated using lateral cephalometric radiographs.

Assessment will be done before treatment (T0) and after obtaining 3-mm positive overjet which will be approximately obtained after 6 months (T1).

The change of the SNA angle before and after using the Orthodontic Removable Traction Appliance compared with this of the control group will be evaluated using lateral cephalometric radiographs.

Assessment will be done before treatment (T0) and after obtaining 3-mm positive overjet which will be approximately obtained after 6 months (T1).

The change of the SNB angle before and after using the Orthodontic Removable Traction Appliance compared with this of the control group will be evaluated using lateral cephalometric radiographs.

Assessment will be done before treatment (T0) and after obtaining 3-mm positive overjet which will be approximately obtained after 6 months (T1).

The level of Pain caused by using the Orthodontic Removable Traction Appliance will be assessed using a questionnaire with a Visual Analog Scale (VAS).

A questionnaire will be given to the patients four times during treatment; after 1day, after 1 week, after 1 month and after 3 months of the application of the appliance.

The level of discomfort caused by using the Orthodontic Removable Traction Appliance will be assessed using a questionnaire with a Visual Analog Scale (VAS).

A questionnaire will be given to the patients four times during treatment; after 1day, after 1 week, after 1 month and after 3 months of the application of the appliance.

The level of acceptance of using the Orthodontic Removable Traction Appliance will be assessed using a questionnaire with a Visual Analog Scale (VAS).

A questionnaire will be given to the patients four times during treatment; after 1day, after 1 week, after 1 month and after 3 months of the application of the appliance.

Inclusion Criteria: Patients in early mixed dentation (8-10 years old). Skeletal class III caused by maxillary deficiency with or without mandibular prognathism judged clinically and confirmed radiographically(ANB≤1). Anterior crossbite on two teeth or more or an edge-to-edge bite. Normal inclination of the lower incisors with the mandibular plane. Exclusion Criteria: Poor oral hygiene. Previous orthodontic treatment. Patients with syndromes, clefts, or craniofacial abnormalities. Severe skeletal class III primarily resulting from mandibular prognathism (ANB less than - 4) Patients with facial asymmetry. Patients with vertical growth pattern.

Individual participant data will be available to the researchers in the department of Orthodontics, Damascus University

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