Adult Orthodontics and Orthognathic Surgery
Adult Orthodontics and Orthognathic Surgery tests how adult treatment differs from growth modification and when to choose camouflage versus surgery. It also tests presurgical decompensation and stability.
Core rules
- Adults do not grow, so skeletal correction requires camouflage, dental compensation, or orthognathic surgery. Periodontal health, bone density, root proximity, restorations, and implants must be assessed first.
- Camouflage moves teeth within the existing skeletal envelope. Surgery corrects the jaw relationship and is indicated for severe skeletal discrepancies, facial asymmetry, airway problems, or when camouflage would be unstable or unaesthetic.
- Presurgical orthodontics usually decompensates the dentition, removing dental compensation so the skeletal discrepancy is fully expressed before surgery. This may temporarily worsen the malocclusion.
- Common procedures include Le Fort I maxillary advancement or impaction, bilateral sagittal split osteotomy for mandibular movement, and genioplasty. Virtual surgical planning improves accuracy.
- Discuss relapse, condylar resorption, nerve injury, airway, and retention. Screen for temporomandibular disorders and sleep apnea.
Worked example
An adult has a Class III relationship, ANB -4 degrees, Wits -7, and negative overjet. Reasoning: the skeletal discrepancy is substantial. Presurgical orthodontics would decompensate the lower incisors and coordinate arches, then surgery might combine maxillary advancement with mandibular setback. If the discrepancy were mild and the profile acceptable, lower incisor retraction could be camouflage, but it would worsen the Class III dental relationship.
Traps
- Decompensating in the wrong direction before surgery.
- Ignoring transverse maxillary deficiency.
- Planning camouflage for a severe skeletal discrepancy that will relapse.
- Failing to consent for nerve injury, relapse, or condylar resorption.