Orthodontic and Orthognathic Surgery By DR. FITRI OCTAVIANTI Department of orthodontics usim
WHAT DO YOU NEED TO KNOW? • Definition • Indication and contraindications • Advantages and disadvantages • Criteria for orthognathic surgery • Steps in orthognathic surgery • Risk and complication of orthognathic surgery
DEFINITION • Orthognathic surgery is the surgical correction of abnormalities of the mandible, maxilla, or both • The underlying abnormality may be present at birth or may become evident as the patient grows and develops or may be the result of traumatic injuries
DEFINITION • Orthognathic surgery is concerned with the correction of dento-facial deformity • In majority of cases a combined surgical and orthodontic approach is required to achieve an optimum result
WHO NEEDS ORTHOGNATHIC SURGERY? • Orthognathic surgery is necessary for those cases with a skeletal discrepancy outside the limits of orthodontic treatment either because of their severity or a lack of growth • Usually performed when growth is virtually complete.
The role of orthodontist • To achieve an occlusion which has good function, aesthetics and stability • To enable the achievements of optimal facial aesthetic • To provide the best means of intraoperativeintermaxillary fixation • To provide for the attachment of post-operative intermaxillary elastics
Indications • Dentofacial problems too severe for orthodontics alone • Non-growing adults • Children with cranial-facial syndromes and severe dentofacial abnormalities, distraction osteogenesis may be considered.
Indications 4. Cases where there are specific documented signs of dysfunction. • These may include conditions involving airway dysfunction such as sleep apnea, temporomandibular joint disorders, psychosocial disorders and or speech impairments
Examples of indications • Severe anteroposterior discrepancies (class II/ class III malocclusions) • Vertical discrepancies (open bite/ deep overbite) • Transverse discrepancies • Skeletal asymmetry
Contraindications • Growing patients • Mild malocclusion • Patient with body dismorphic syndrome • Medical problems
Advantages • Aesthetic • 75% - 80% of patients seeks aesthetic improvement • Psychological • About 90% of patients who undergo orthognathic surgery report satisfaction with the outcome and over 80% say they would recommend such treatment to others and would undergo it again • Functional • Able to speak and eat normally
Disadvantages • Surgical risk • Relapse • Unsatisfied with results • Motivated patients • Availability of surgeons + orthodontist • Cost
Criteria for Orthognathic Surgery(The American Association of Oral and Maxillofacial Surgeons, 2008) • Anteroposterior discrepancies • Vertical discrepancies • Transverse discrepancies • Asymmetries
1. Anteroposterior discrepancies • Maxillary/mandibular incisor relationship: overjet of 5mm or more, or a 0 to a negative value (norm 2mm). • Maxillary/mandibularanteroposterior molar relationship discrepancy of 4mm or more (norm 0 to 1mm).
2. Vertical discrepancies • Open bite • No vertical overlap of anterior teeth. • Unilateral or bilateral posterior open bite greater than 2mm • Deep overbite with impingement or irritation of buccal or lingual soft tissues of the opposing arch. • Supra eruption of a dentoalveolar segment due to lack of occlusion.
3. Transverse discrepancies • Presence of a transverse skeletal discrepancy which is two or more standard deviations from published norms. • Total bilateral maxillary palatal cusp to mandibularfossa discrepancy of 4mm or greater, or a unilateral discrepancy of 3mm or greater, given normal axial inclination of the posterior teeth.
4. Asymmetries • Anteroposterior, transverse or lateral asymmetries greater than 3mm with concomitant occlusal asymmetry.
Steps in Orthognathic Surgery 1. Diagnosis and treatment planning 2. Pre-surgical orthodontics 3. Orthognathic surgery 4. Post-surgical orthodontics
1. Diagnosis and Treatment Planning • A team approach is essential -orthodontist and surgeon to produce a coordinated treatment plan (joint clinic) • Establish whether they are concerned with their skeletal pattern, the position of their teeth or a combination of two
The patient should be made fully aware of the various treatment options, the advantages, disadvantages and short and long term complications of each of possible treatment
2. Presurgical orthodontics Bring the teeth to a more normal position over their respective skeletal bases AIMS: • Alignment • Decompensation • Arch coordination • Creation of space for interdental osteotomy cuts • Falitation of the placement of temporary intermaxillary fixation during surgery.
Lateral chephalogram and intra-oral photograph bebore and after presurgical surgery for management Class III malocclusion. Increase in reverse overjet during decompensation.
Space created for interdental cuts distal to the maxillary canines. The reserve tip of canines produced intentionally to move the canine root away from osteotomy site.
At the end of presurgical phase, heavy rectangular stainless steel archwiresare placed (0.019 x 0.025 SS) • Metal hooks are crimped directly into the archwire
3. The surgical phase of treatment • Prior to surgery records should be taken so that final surgical plan can be confirmed • This include study models, photographs and lateral cephalogram • The models should be mounted on a semi adjustable articulator
Acrylic intermediate and or final interocclusal wafers are also constructed from the models
Type of surgical procedure: • Bilateral sagittal split mandibularosteotomy • Vertical subsigmoidosteotomy • Mandibular distraction • Le fort I maxillary • Le fort II maxillary • Le fort III maxillary • Segmental osteotomy • Genioplasty
Range of surgical movement: • Maxilla can be moved forwards, upwards and downwards • Mandibula can be moved forwards and backwards • Chin can be moved forwards, backwards, upwards and downwards
Bilateral sagittal split mandibularosteotomy • Vertical subsigmoidosteotomy
Mandibular distraction • Le fort I maxillary
Le fort II maxillary • Le fort III maxillary
Segmental osteotomy • Genioplasty
4. Postsurgical orthodontic • 1-7 days post operatively, light intermaxillary elastics may need to be placed to detail the occlusion • In the arch where most vertical movement is required, a more flexible archwire may be used such as rectangular nickel titanium • In the opposing arch where vertical movement is not required, a stiffer rectangular steel wire can remain in place
The postsurgical orthodontic usually last 3 – 6 months depending on the degree of presurgical orthodontic already carried out • At completion of treatment the fixed appliances are removed and retainers are fitted
Postsurgical stage, with light vertical elastics to maintain the vertical position of the teeth
Maxillary archwire .017x.025 beta-Ti Mandibular archwire 0.16 SS
Risk and Complications • 1. Preoperative (orthodontic complications) 2. Intra operative 3. Postoperative
1. Preoperative (orthodontic complications) • Decalcification of enamel • Gingival recession • Alveolar bone loss • Root resorption
2. Intraoperative • Damage to the neurovascular bundle during mandibularosteotomy leading to parasthesia, this occurs in 32% of patients and can be disturbing for 3% of patients • Loss of blood supply to part of maxilla • Hemorrhage
Failure of bone to split cleanly • Failure to relocate the osteotomised fragments into their correct preplanned position • Damage to the teeth adjacent to osteotomy site • Fatality
3. Postoperative • Failure of the osteotomy to undergo bony union • The bone plate perforates through mucosa with chronic infection • Relapse towards the preoperative position
Hierarchy of stability • Stability after surgical repositioning of the jaws varies a great deal, depending on the direction of movement, type of fixation used and the surgical technique that was employed • Superior repositioning of the maxilla is the most stable procedure and closely followed by mandibular advancement in patient with normal or decreased anterior face height
Problem: horizontal deficiency and vertical chin excess Surgical procedure: vertical reduction with vertical advancement of the chin
Problem: Class II mandibular deficiency Surgical procedure: sagittal split osteotomy with advancement
Problem: Excess vertical maxillary growth Surgical prosedure: Le fort I osteotomy with maxillary impaction
Problem: Class III with mandibular excess Surgical procedure: sagittal split osteotomy with setback
Problem: Class III maxillary deficiency Surgical procedure: Le fort I osteotomy with maxillary advancement
Problem: Class III maxillary deficiency mandibular excess Surgical treatment: - Le Fort I osteotomy of maxillary advancement - sagittal split osteotomy of mandibular with setback