Evaluation of Soft Tissue Profile Changes Following Autogenous Fat or Onlay Polyetheretherketone (PEEK) Augmentation Versus Sliding Genioplasty for Correction of Deficient Chin

Phase 3

Brief Summary: Fat is a filler with ideal properties as it naturally integrates into tissues with 100 % biocompatibility. Moreover, fat contains different cell types, including adipocytes, fibroblasts, smooth muscle cells, endothelial cells, and adipogenic progenitor cells called"preadipocytes"2, adipose-derived stem cells (ASCs) which have a differentiation potential similar to that of other mesenchymal stem cells and it could be harvested in great amounts with minimal donor-site morbidity, ASCs have proved to be particularly promising for regenerative therapies. In addition, it's relatively inexpensive and readily available, which makes it an attractive alternative for facial augmentation.

On the other hand PEEK is considered a highly biocompatible material with mechanical properties almost similar to cortical bone. It is widely used in cranioplasties and facial reconstruction.

Detailed Description: The chin is the most noticeable facial structure which plays an important role in perception of facial esthetics; therefore deficient chin is considered an annoying defect for the patient. Traditional techniques used for correction, which are osseous genioplasty and alloplastic augmentation, have some reported complications. These complications include hematoma in the floor of the mouth; though a rare complication is considered to be a life threatening condition. Also, wound dehiscence, infection, Chin hypoesthesia/dysesthesia due to mental nerve injury which occurs in 3.4% to 12% of cases , chin ptosis, lip ptosis, drooling, and an increase in lower teeth show due to failure to reattach the mentalis muscle to its natural origin on the anterior face of the mandibular body and tooth root damage which may occur during the osteotomy. Also bone resorption, implant displacement, infection and foreign body reaction were reported as a complication with some alloplastic implants .

This study aims to avoid the complications of surgical correction of deficient chin by using less invasive approach.

Trial design:

3 Groups of patients will be assigned to this trial: Study group1: Will use autogenous fat augmentation in deficient chin. Study group2: Will use onlay PEEK augmentation in deficient chin. Control group: Surgical correction of deficient chin with sliding genioplasty. Trial design: Randomized Controlled clinical Trial

Recruitment & Eligibility

Inclusion Criteria

•.Medically free patients.

Exclusion Criteria

Patients with systemic condition contraindicating with the surgical procedure.
Previously corrected chin.
Patients indicated for other skeletal mandibular procedure during the same surgical session.

Arm && Interventions

Group	Intervention	Description
autogenous fat	fat filler,PEEK,sliding genioplasty	autogenous fat augmentation in deficient chin will be harvested from lower abdomen,inner or outer thigh
PEEK	fat filler,PEEK,sliding genioplasty	Will use onlay PEEK augmentation in deficient chin.Virtual planning will be done using mimics software. A virtual osteotomy of the chin will be performed at the inferior border of the mandible same alignments as sliding genioplasty, then segmentation of the chin area will be done and according to the soft tissue analysis adjustment will be performed.
Osseous sliding genioplasty	fat filler,PEEK,sliding genioplasty	Under general anesthesia, the preparation and the incision line will be performed same as PEEK augmentation .After complete exposure of the bone repositioning of the chin will be performed. Finally fixation will be obtained using x shape titanium plate.

Primary Outcome Measures

Name	Time	Method
soft tissue analysis	year follow up	assessment of soft tissue profile changes using computerized software ,land marks will be determined on soft tissue mask of patient's cone beam computed tomography (cbct) .The Frankfort horizontal (FH) plane will be chosen as a reference line .Horizontal soft tissue changes will be recorded parallel to the FH line and perpendicular on the nasion vertical (NV), whereas the vertical soft tissue changes will be recorded parallel to the NV and perpendicular on the FH line.The advancement will be measured by the change in the position of point Pg preoperatively and postoperatively (T2) from the NV line.The points (Pg, Pg', Me, Me', and B) will be measured for vertical and horizontal movements by a line from each point and perpendicular to the NV and the FH

Secondary Outcome Measures

Name	Time	Method