Orthognathic Surgical Treatment

Adriana Da Silveira, DDS, MS, PhD

ORTD 323

Summer 2002

Indications for Orthognathic Surgery

• Severity of skeletal and dental malocclusion

• When growth modification can not be achieved

• Esthetic and psychosocial considerations

Timing of Surgery

• Usually done when all growth is complete

• Assessed by superimposition of serial lat cephs

• Can be performed when growth is not yet complete in cases of psychosocial problems or great severity when function is compromised (i.e. breathing, chewing)

Orthognathic Surgery• Correction of A-P relationships:

• maxillary advancement

• retraction of anterior maxillary segment

• mandibular advancement

• mandibular setback

• double jaw surgery

Orthognathic Surgery

• Correction of Vertical Relationships:

• maxillary impaction/intrusion

• maxillary extrusion

• mandibular ramus surgery

Orthognathic Surgery

• Correction of Transverse Relationships:

• surgically assisted maxillary expansion

• surgically assisted mandibular expansion

Orthognathic Surgery

• Correction of Asymmetries:

• maxilla

• mandible

• maxilla and mandible

Surgical Techniques

• Le Fort I

• Le Fort II

• Le Fort III

Le Fort I

Le Fort II

Le Fort III

Surgical Techniques

• BSSO

• Genioplasty

Pre Surgical Orthodontic Objectives

• To level and align the arches and make them compatible

• to resolve crowding and/or spacing

• to establish anteroposterior and vertical position of incisors (decompensate)

• to place teeth relative to their own supporting bone

Check List for Treatment Planning

• A-P relationships maxillary deficiency/protrusion

mand prognathism/deficiency

amount of deficiency• Vertical relationships open bite

deep bite• Transverse relationships crossbites

before surgery expansion

surgically assisted expansion

during surgery {

Check List for Treatment Planning

• Asymmetries cant of occlusal plane

mandible/chin deviation• Occlusal relationships• Missing teeth/ malformed teeth• Genioplasty• Nose/lip relationship - rhinoplasty

Diagnostic Records

• Analysis of pictures

• cephalometric analysis

• Surgical prediction - STO

• model/occlusion analysis

STO-Mandible Only

STO-Maxilla Only

STO-Double Jaw

STO-Double Jaw

Preparation for Surgery

• Removal of third molars 6 months before mandibular osteotomy

• Check for any TMJ problems

• Manipulate models mounted in an articulator to check for interferences and occlusion

• Splint fabrication (1 or 2 splints)

• Prognathic, increased lower facial height, Cl III, open bite, crowding on the upper arch.

• Previous orthodontic treatment with extraction of lower first premolars.

Mandibular Setback with Maxillary Advancement and Impaction for Correction

of Prognathism and Open Bite

Mandibular Advancement for Correction of Retrognathism

• Retrognathic, decreased lower facial height, Cl II, deep bite, protruded upper incisors, spacing.

• Previous orthodontic treatment w/ extraction of upper first premolars.

Mandibular Setback for with Correction of Prognathism and Asymmetry

Maxillary Advancement with Le Fort III for Correction of Maxillary Deficiency

Maxillary Advancement with Le Fort III for Correction of Maxillary Deficiency

• Additional Le Fort I surgical procedure will be performed after initial orthodontic treatment has been completed for correction of maxillary deficiency and open bite.

Post Surgical Orthodontic Treatment

• 1 week: check occlusion, splint and appliances• 4-6 weeks: reinitiate orthodontic tx (after range

of motion and stability are achieved)

remove splint

change to light wires and light vertical elastics• treatment usually completed in 4 to 12 months

(average 6 months)

{

Relapse and Stability

• Rigid fixation has improved stability

• Stability is mostly influenced by the pattern of rotation of the mandible as it is advanced

• Advancement of maxilla and/or mandible will stretch soft tissues promoting relapse

• The more advancement needed, the greater the probability for relapse

Relapse and Stability

Distraction Osteogenesis• First described by Ilizarov for limbs• Distraction osteogenesis = callostasis = stretching of

a bone callus• Gradual distraction of bones is accompanied by the

soft tissues = less probability of relapse• Can be performed for the mandible, maxilla,

calvarium, orbit, midpalatal suture and maxillary or mandibular alveolus

• Distraction devices can be internal or external• Internal devices can also be resorbable

Distraction Osteogenesis for the Mandible

Distraction Osteogenesis for the Maxilla