Surgical Orthodontics and Orthognathic Surgery Comprehensive Study Notes

Context: These study notes are prepared for BDS-Final Year students specializing in surgical orthodontics.
Definition of Orthognathic Surgery: This refers to the surgical procedures utilized to correct severe dentofacial deformities through the repositioning of the jaws.

Primary Indications: * Extreme severity of skeletal and dental malocclusion. * Situations where growth modification techniques cannot be successfully achieved. * Critical esthetic and psychosocial considerations for the patient.
Ideal Case Profiles for Orthognathic Surgery: * Severe skeletal Class II and Class III malocclusions. * Skeletal deep bite and skeletal open bite cases. * Extreme vertical excess or vertical deficiency involving the maxilla and/or mandible. * Presence of severe dentoalveolar problems. * Cases with an extremely compromised periodontal situation. * Skeletal asymmetry of the face.

This hierarchy ranks procedures from those that are most predictable and stable to those that are considered problematic and less stable.

Very Stable: * Maxilla up (superior repositioning).
Stable: * Mandible forward (Note: This is stable primarily in patients with a short or normal face height). * Chin movement in any direction.
Stable (Requires Rigid Fixation Only): * Maxilla forward. * Maxilla correction for asymmetry. * Combined Maxilla up (Mx up) and Mandible forward (Mn forward).
Problematic (Less Predictable/Stable): * Combined Maxilla forward (Mx forward) and Mandible back (Mn back). * Mandible correction for asymmetry. * Mandible back. * Maxilla down (inferior repositioning). * Maxilla wider (transverse expansion).

General Rule: Surgical procedures are usually performed after all biological growth is complete.
Assessment Method: Completion of growth is assessed through the superimposition of serial lateral cephalograms.
Recommended Timing by Specific Clinical Problem: * Mandibular Excess: Wait until growth is complete. * Mandibular Deficiency: * Girls: $14-16$ years of age. * Boys: $18$ years of age. * Maxillary Excess: Perform after growth completion. * Maxillary Deficiency: May be delayed until the adolescent growth spurt. * Short Face: Timing is similar to the mandibular deficiency protocol. * Long Face: Early surgery is explicitly not recommended. * Asymmetry: Early treatment is recommended specifically when abnormal growth is actively worsening the clinical situation.

Diagnostic Components: * Comprehensive History. * Clinical Evaluation comprising: * Frontal view analysis. * Profile view analysis. * Soft tissue assessment. * Temporomandibular Joint (TMJ) evaluation. * Dental health assessment. * Occlusal assessment. * Radiographic evaluation. * In-depth cephalometric examination.
Standard Treatment Sequence: * Step 1: Pre-surgical orthodontics (includes leveling, alignment, and any necessary extractions). * Step 2: The surgical procedure itself. * Step 3: Post-surgical orthodontics. * Step 4: Finishing procedures. * Step 5: Retention phase.

Surgeries are classified based on the plane of the relationship they intend to correct:

Correction of Anteroposterior (A-P) Relationships: * Maxillary advancement. * Maxillary setback. * Mandibular advancement. * Mandibular setback. * Double jaw surgery (combination of both).
Correction of Vertical Relationships: * Maxillary impaction. * Maxillary down graft. * Mandibular ramus surgery.
Correction of Transverse Relationships: * Surgically assisted maxillary expansion. * Surgically assisted mandibular expansion.
Correction of Asymmetries: * Maxillary procedures. * Mandibular procedures. * Combined maxilla and mandible procedures.

Camouflage vs. Surgery: * Orthodontic camouflage often involves the extraction of upper premolars to mask underlying skeletal issues. * Orthognathic surgery (such as Lefort I Osteotomy) addresses the skeletal base directly.
Broad Categories of Surgical Techniques: * Maxillary surgeries. * Mandibular surgeries. * Combination surgeries. * Dentoalveolar surgeries. * Distraction osteogenesis. * Adjunctive facial procedures.
Specific Maxillary Procedures: * Lefort Osteotomy (Three levels categorized as Lefort I, Lefort II, and Lefort III). * Segmental Osteotomy (often used in cases like Class II maxillary protrusion). * Surgically Assisted Rapid Palatal Expansion (SARPE).
Specific Mandibular Procedures: * Sagittal split osteotomy. * Oblique subcondylar osteotomy. * Bilateral Sagittal Split Osteotomy (BSSO): Used for both mandibular advancement and mandibular setback.