Effectiveness of Two Skeletally Anchored Force Mechanics for Skeletal Class II Correction in Growing Patients

Study Overview
=================
Brief Summary
-----------------
Patients with skeletal Class II malocclusion due to mandibular retrognathism will be recruited and randomly allocated to three equal groups. first group will be treated by pushing orthopedic force mechanics, second group will be treated by pulling orthopedic force mechanics, and third group will be observed for 9 months to detect the natural growth changes. Skeletal changes will be evaluated and the treatment changes will be compared with the natural growth changes. The study hypothesis is that use of direct bimaxillary miniplate anchorage in conjunction with fixed functional appliance (pushing orthopedic force) or closed coil spring (pulling orthopedic force) will induce statistically significant skeletal mandibular growth in comparison to natural mandibular growth changes.

Detailed Description
-----------------
A randomized controlled clinical trial will be conducted to address the aim of the study. Thirty-nine growing patients with skeletal Class II malocclusion due to mandibular retrognathism will be recruited. The sample will be randomly allocated to three equal groups, each including thirteen subjects. Group A will be treated by pushing orthopedic force mechanics using fixed functional appliance (Sabbagh Advanced Repositioning Appliance) anchored to four miniplates (two miniplates inserted in the mandibular symphysis and two infrazygomatic miniplates), and Group B, will be treated by pulling orthopedic force mechanics using Class II springs (CS Class II correction device) anchored to four miniplates (two inserted in the mandibular posterior buccal segment and two inserted in the maxillary anterior segment). In both groups, the appliances will be removed after reaching an edge-to-edge incisor relationship or after 9 months, whichever happens first. A similar third group (Group C) will be observed for 9 months to detect the natural growth changes. Skeletal changes will be evaluated using pretreatment and posttreatment cone beam computed tomography scans (CBCT). The treatment changes will be compared with the natural growth changes observed in group C. Other variables will be also examined including, the dentoalveolar effects, the soft tissue profile, and the patient's acceptance to this treatment modality.

Official Title
-----------------
Effectiveness of Two Skeletally Anchored Force Mechanics for Correction of Skeletal Class II Malocclusion in Growing Patients (A Randomized Controlled Clinical Trial)

Conditions
-----------------
Malocclusion

Intervention / Treatment
-----------------
* Procedure: Miniplates in mandibular symphysis & infrazygomatic
* Procedure: Miniplates in external oblique ridge & anterior maxillary region


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Chronological age ranges from 11 years to 13 years. Skeletal Class II malocclusion with a deficient mandible (SNB ≤ 76°). Horizontal growth pattern (MP/SN ≤ 39°). Angle Class II division 1 malocclusion with at least 5 mm overjet. Mandibular arch crowding less than 5 mm. The patients have to be in the prepubertal growth stage (cervical maturational stage 3 or 4) when applying orthopedic force. Patients with good oral hygiene, and a healthy periodontal condition. Exclusion Criteria: Patients who underwent previous orthodontic treatment. Patients with previous craniofacial surgeries, chronic diseases, syndromes, or growth problems that may affect bone. Any signs or symptoms of para-functional habits or previous history of temporomandibular disorders. Extracted or missing upper permanent teeth (except for third molars).

Ages Eligible for Study
-----------------
Minimum Age: 11 Years
Maximum Age: 13 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Miniplates in mandibular symphysis & infrazygomatic<br> | Procedure: Miniplates in mandibular symphysis & infrazygomatic<br>* Fixed functional appliance (pushing orthopedic force) in conjunction with direct skeletal anchorage<br>|
| Active Comparator: Miniplates in external oblique ridge & anterior maxillary region<br> | Procedure: Miniplates in external oblique ridge & anterior maxillary region<br>* Coil spring (pulling orthopedic force) in conjunction with direct skeletal anchorage<br>|
| No Intervention: Growing skeletal Class II subjects<br> | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in the effective mandibular length (Co-Gn) | Correction of the skeletal Class II relation. This outcome will be detected by measuring the mean change in the effective mandibular length (Co-Gn) and position on CBCT images from baseline data (T1) and after appliance removal (T2) and will be compared with the growth changes observed in the control group | at baseline and after treatment completion about 9 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in maxillary length (Co-A) | The effective maxillary length (Co-A) and position changes will be measured after and chin will be measured. | at baseline and after treatment completion about 9 months | 
| Changes in the soft tissue angle of convexity | the position of the upper and lower lips, and chin will be measured. | at baseline and after treatment completion about 9 months | 
| patient acceptance of treatment | The patient's acceptance to the treatment will be evaluated using a visual analog scale questionnaire after removal of the appliances. | After treatment completion about 9 months |