Functional Appliance for Orthognathic Surgery

Post-surgical Stability in Mandibular Advancement Using Postsurgical Versus Presurgical Computer Guided Functional Appliance. (RANDOMIZED CLINICAL TRIAL)

The unstable condylar position in the glenoid fossa is a critical problem for postsurgical instability after mandibular advancement with subsequent mandibular relapse. The habitual forward occlusion in class II patients creates unstable condyle to glenoid fossa relationship making it hard for clinicians to determine the amount of mandibular advancement. Splint therapy is considered as a preoperative reversible nonsurgical condylar repositioning option in addition to its adjunctive effect for pain relief in TMJ symptomatic patients. To minimize this relapse, presurgical functional appliance therapy has been proposed and has shown promising outcomes.

Study Overview

• Status: Completed
• Conditions: Orthognathic Surgery
• Intervention / Treatment: Device: Postsurgical computer guided functional appliance

Detailed Description

The aim of this study is to compare the effect of postsurgical versus presurgical computer guided functional appliance in relapse prevention after mandibular advancement surgery.

Surgical procedure:

1. Owbgeser incision will be performed to expose the buccal and lingual aspects of the ramus angle region.
2. CAD/CAM generated preoperative wafer will be placed on the lower arch dentition, the guide has an extension to guide medial, vertical, oblique cuts as well as screw holes for reference landmarks for proximal segment & tooth bearing segment.
3. Drilling of all the reference landmarks on the proximal segment and locating medial, vertical, oblique cuts.
4. Removal of guide, then BSSO is performed.
5. The final wafer is placed, the guiding hole on the proximal segment will then be realigned with the previously drilled screw holes, fixation using mono cortical screws then drilling screw holes for plate fixation.
6. Fixation of the osteotomy using 2.0 mm pre-bent mini plates.
7. A positioning screw will be added to improve stability against rotational forces.

b-Functional appliance

Postsurgical computer guided functional appliance:

After achieving ideal condylar poison by computer guided surgery. The distal extension of the final occlusal wafer will be cut and the appliance will be fitted to be utilized as a postsurgical functional appliance for condylar adaptation. Patients will be instructed to wear the splints continuously for 3 months, only being allowed to remove them when eating and brushing their teeth.

Presurgical computer guided functional appliance:

Using the software, 3D digitized mandible will be virtually repositioned in ideal centric relation through accurate adjustment of the condyle in its glenoid fossa. Patients' dental casts will be scanned, and digitized into a virtual 3D model and superimposed to the CT cuts into the virtual plan software environment in order to produce preoperative CAD/CAM splint on the adjusted centric occlusion. Patients will be instructed to wear the splints continuously for 3 months, only being allowed to remove them when eating and brushing their teeth.

c- Follow up

All patients will be advised to stay on a soft diet for 4-6 weeks to avoid any undue forces on the surgical site. Postoperative CT and lateral cephalogram will be obtained, immediately postoperative and 12 months later respectively.

• Study Type: Interventional
• Enrollment (Actual): 18
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo, Egypt, 11553
    • outpatient clinic of Oral and Maxillofacial Surgery department- Cairo University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age of the patient above 18 years
• Patients in need of bilateral sagittal split osteotomy for mandibular advancement.
• All patients are free from any systemic disease that may affect normal bone healing.
• Sufficient dentition to reproduce the occlusal relationships
• Patient's consent to participate

Exclusion Criteria:

• Patients with any systemic disease that may affect normal healing
• Intra-bony lesions or infections that may interfere with surgery
• Previous orthognathic surgeries

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: postsurgical computer guided functional appliance; After achieving ideal condylar poison by computer guided surgery. The distal extension of the final occlusal wafer will be cut and the appliance will be fitted to be utilized as a postsurgical functional appliance for condylar adaptation. Patients will be instructed to wear the splints continuously for 3 months, only being allowed to remove them when eating and brushing their teeth.	Device: Postsurgical computer guided functional appliance; After achieving ideal condylar poison by computer guided surgery. The distal extension of the final occlusal wafer will be cut and the appliance will be fitted to be utilized as a postsurgical functional appliance for condylar adaptation. Patients will be instructed to wear the splints continuously for 3 months, only being allowed to remove them when eating and brushing their teeth.
Active Comparator: Presurgical computer guided functional appliance; Using the software, 3D digitized mandible will be virtually repositioned in ideal centric relation through accurate adjustment of the condyle in its glenoid fossa. Patients' dental casts will be scanned, and digitized into a virtual 3D model and superimposed to the CT cuts into the virtual plan software environment in order to produce preoperative CAD/CAM splint on the adjusted centric occlusion. Patients will be instructed to wear the splints continuously for 3 months, only being allowed to remove them when eating and brushing their teeth.	Device: Postsurgical computer guided functional appliance; After achieving ideal condylar poison by computer guided surgery. The distal extension of the final occlusal wafer will be cut and the appliance will be fitted to be utilized as a postsurgical functional appliance for condylar adaptation. Patients will be instructed to wear the splints continuously for 3 months, only being allowed to remove them when eating and brushing their teeth.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from postoperative sagital position of the mandible at 12 months (skeletal stability)	Method of Measurement: Lateral cephalogram Unit of Measurement: mm	immediately postoperative and 12 months later

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of condylar deviation	Method of Measurement: CT scan Unit of Measurement: mm	immediately postoperative and 12 months later

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Distal segment linear deviation	Method of Measurement: CT scan Unit of Measurement: mm	immediately postoperative and 12 months later
Distal segment angular deviations	Method of Measurement: CT scan Unit of Measurement: degree	immediately postoperative and 12 months later

Collaborators and Investigators

• Sponsor: Cairo University

Publications and helpful links

General Publications

• Ha N, Hong Y, Qu L, Chung M, Qu R, Cai X, Fang B, Jiang L. Evaluation of post-surgical stability in skeletal class II patients with idiopathic condylar resorption treated with functional splint therapy. J Craniomaxillofac Surg. 2020 Mar;48(3):203-210. doi: 10.1016/j.jcms.2020.01.004. Epub 2020 Jan 11.
• Bailey L', Cevidanes LH, Proffit WR. Stability and predictability of orthognathic surgery. Am J Orthod Dentofacial Orthop. 2004 Sep;126(3):273-7. doi: 10.1016/S0889540604005207. No abstract available.
• Proffit WR, Turvey TA, Phillips C. The hierarchy of stability and predictability in orthognathic surgery with rigid fixation: an update and extension. Head Face Med. 2007 Apr 30;3:21. doi: 10.1186/1746-160X-3-21.
• Costa F, Robiony M, Toro C, Sembronio S, Polini F, Politi M. Condylar positioning devices for orthognathic surgery: a literature review. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008 Aug;106(2):179-90. doi: 10.1016/j.tripleo.2007.11.027. Epub 2008 Apr 16.
• TRAUNER R, OBWEGESER H. The surgical correction of mandibular prognathism and retrognathia with consideration of genioplasty. II. Operating methods for microgenia and distoclusion. Oral Surg Oral Med Oral Pathol. 1957 Sep;10(9):899-909. doi: 10.1016/s0030-4220(57)80041-3. No abstract available.
• Bell WH, Schendel SA. Biologic basis for modification of the sagittal ramus split operation. J Oral Surg. 1977 May;35(5):362-9.
• Wyatt WM. Sagittal ramus split osteotomy: literature review and suggested modification of technique. Br J Oral Maxillofac Surg. 1997 Apr;35(2):137-41. doi: 10.1016/s0266-4356(97)90691-4.
• Joss CU, Vassalli IM. Stability after bilateral sagittal split osteotomy advancement surgery with rigid internal fixation: a systematic review. J Oral Maxillofac Surg. 2009 Feb;67(2):301-13. doi: 10.1016/j.joms.2008.06.060.
• Epker BN, Wessberg GA. Mechanisms of early skeletal release following surgical advancement of the mandible. Br J Oral Surg. 1982 Sep;20(3):175-82. doi: 10.1016/s0007-117x(82)80035-8.
• Worms FW, Speidel TM, Bevis RR, Waite DE. Posttreatment stability and esthetics of orthognathic surgery. Angle Orthod. 1980 Oct;50(4):251-73. doi: 10.1043/0003-3219(1980)0502.0.CO;2.
• Angle AD, Rebellato J, Sheats RD. Transverse displacement of the proximal segment after bilateral sagittal split osteotomy advancement and its effect on relapse. J Oral Maxillofac Surg. 2007 Jan;65(1):50-9. doi: 10.1016/j.joms.2005.11.117.
• Nebbe B, Brooks SL, Hatcher D, Hollender LG, Prasad NG, Major PW. Interobserver reliability in quantitative MRI assessment of temporomandibular joint disk status. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1998 Dec;86(6):746-50. doi: 10.1016/s1079-2104(98)90215-3.

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2021
• Primary Completion (Actual): May 1, 2023
• Study Completion (Actual): May 1, 2024

Study Registration Dates

• First Submitted: August 4, 2021
• First Submitted That Met QC Criteria: August 16, 2021
• First Posted (Actual): August 17, 2021

Study Record Updates

• Last Update Posted (Estimated): November 7, 2024
• Last Update Submitted That Met QC Criteria: November 5, 2024
• Last Verified: November 1, 2024

More Information

Terms related to this study

• Other Study ID Numbers: Orthognathic surgery

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No