Clinical trial NCT03354442: Treatment of Class III Malocclusion Using Modified Fixed Mandibular Retractor Appliance
Official title: Evaluation of the Efficacy of Modified Fixed Mandibular Retractor Appliance in the Treatment of Class III Malocclusion: A Clinical Randomized Controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Malocclusion, Angle Class III
Keywords: Class III treatment
Modified Fixed Mandibular Retractor Appliance
RCT
Lead sponsor: Damascus University
Sponsor class: OTHER
First posted: 2017-11-28
Enrollment: 44
Sex: ALL
Minimum age (years): 7
Maximum age (years): 9
Standard ages: CHILD
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: This experimental study aims to evaluate the efficiency of the Modified Fixed Mandibular Retractor 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 untreated control group.

The soft and hard tissue changes will be assessed using lateral cephalometric radiographs before the treatment and after obtaining 3mm positive overjet.

Detailed description: This research aimes to evaluate the effects of a Class III functional appliance \[the modified fixed mandibular retractor (MFMR)\] in the early treatment of skeletal Class III deformities.

It was not ethical to expose all candidate children to radiographic examination. Therefore, the assessment of skeletal Class III malocclusion was based on clinical judgment. Each patient was examined, while his/her mandible was kept at its retruded contact position to evaluate both jaws in space. Those who met the inclusion criteria were then sent to the radiographic department.

The radiographic lateral cephalograms were obtained in the patients' habitual occlusion.

All patients in the treatment group were treated by one specialist orthodontist 'AA' using the MFMR. The appliance consisted of the following elements: (1) Two acrylic upper posterior bite planes which cover the deciduous and permanent molars ( 2) Two transpalatal arch (0.8-mm TMA) with opposite U loop, the anterior one is near the first deciduous molars while the posterior one is near the first permanent molars (3) upper reversed labial bow (0.9-mm stainless steel) extending to the cervical edges of the mandibular anterior teeth from the labial surface of the lower primary canine on one side to the other labial surface of the contralateral tooth. This bow will be activated to hold the mandible in its maximum posterior physiologic position; and (4) the anterior spring (0.8-mm TMA) which starts from the acrylic bite plane in both sides, makes loop, then bends to touch the cingulum of upper incisors to procline the upper permanent incisors when diagnosed as retroclined.

The untreated group will receive no orthodontic treatment during the observation period. According to the Dental School Local Research Ethics Committee's guidelines, all children in the untreated group will receive orthodontic treatment after the end of the observational period of the study at no cost.

Eligibility criteria: Inclusion Criteria:

* Patients in early mixed dentation (7-9 years old).
* Skeletal class III caused by mandibular prognathism with or without maxillary deficiency judged clinically and confirmed radiographically (ANB≤1).
* Anterior crossbite on two teeth or more.
* Normal inclination of the lower incisors with the mandibular plane.
* Good oral hygiene.

Exclusion Criteria:

* Poor oral hygiene.
* Previous orthodontic treatment.
* Patients with syndromes, clefts, or craniofacial abnormalities.
* Severe skeletal class III resulting primarily from mandibular prognathism (ANB less than - 4 with no functional shift on closure)
* Patients with facial asymmetry.
* Patients with vertical growth pattern.

Primary outcomes:
measure: ANB angle changes
timeFrame: Changes will be evaluated before treatment and after obtaining 3mm positive overjet, which will take approximately 8 months
Secondary outcomes:
measure: SNA angle changes
timeFrame: Changes will be evaluated before treatment and after obtaining 3mm positive overjet, which will take approximately 8 months
measure: SNB angle changes
timeFrame: Changes will be evaluated before treatment and after obtaining 3mm positive overjet, which will take approximately 8 months
measure: Profile changes
timeFrame: Changes will be evaluated before treatment and after obtaining 3mm positive overjet, which will take approximately 8 months
measure: Upper incisor angle changes
timeFrame: Changes will be evaluated before treatment and after obtaining 3mm positive overjet, which will take approximately 8 months
measure: Lower incisor angle changes
timeFrame: Changes will be evaluated before treatment and after obtaining 3mm positive overjet, which will take approximately 8 months
Other outcomes:
Locations:
city: Damascus
country: Syrian Arab Republic
facility: Damascus University
Study officials:
affiliation: Department of Orthodontics, Faculty of Dentistry, Damascus University, Damascus, Syria
name: Ahmad S Burhan, PhD.
role: STUDY_CHAIR
References:
citation: Alhaija ES. Skeletal, dental and soft tissue changes in postural class III malocclusion treated with a maxillary removable appliance. J Clin Pediatr Dent. 2006 Winter;31(2):149-52. doi: 10.17796/jcpd.31.2.u286433up81kt472.
citation: Akin M, Ucar FI, Chousein C, Sari Z. Effects of chincup or facemask therapies on the orofacial airway and hyoid position in Class III subjects. J Orofac Orthop. 2015 Nov;76(6):520-30. doi: 10.1007/s00056-015-0315-3.
citation: Majanni AM, Hajeer MY. The Removable Mandibular Retractor vs the Bone-anchored Intermaxillary Traction in the Correction of skeletal class III Malocclusion in children: A Randomized Controlled Trial. J Contemp Dent Pract. 2016 May 1;17(5):361-71. doi: 10.5005/jp-journals-10024-1856.
citation: Seehra J, Fleming PS, Mandall N, Dibiase AT. A comparison of two different techniques for early correction of Class III malocclusion. Angle Orthod. 2012 Jan;82(1):96-101. doi: 10.2319/032011-197.1. Epub 2011 Aug 1.
citation: Atalay Z, Tortop T. Dentofacial effects of a modified tandem traction bow appliance. Eur J Orthod. 2010 Dec;32(6):655-61. doi: 10.1093/ejo/cjp153. Epub 2010 Mar 26.
citation: Kapur A, Chawla HS, Utreja A, Goyal A. Early class III occlusal tendency in children and its selective management. J Indian Soc Pedod Prev Dent. 2008 Sep;26(3):107-13. doi: 10.4103/0970-4388.43191.