Orthognathic Surgery Flashcards
What is orthographic surgery?
Surgery to correct the irregularities in the jaw bones and re-position either one or both of the jaws so that the patient bites together in a better position.
What are the fundamentals of orthographic surgery?
- Team approach- MDT
- History- find out how the deformity happened, what they don’t like about it.
- Careful clinical examination
- Special Investigations
- Prediction planning.
- Stable surgical techniques
Who might be involved in the MDT for orthographic surgery?
Orthodontist
Maxillofacial surgeon
Paediatric dentist
GDP
Psychologist
Speech and language therapist
Dietician
Technician
Restorative dentist
Why is a psychologist required prior to orthognathic surgery?
Understand the motivation for surgery- is there an underlying psychological disorder? Body dysmorphia?
Post-surgical depression
Psychological adaptation to a new face
What is the patient’s mental state? Anxious? Depressed?
Previous or current mental health conditions.
What does the technician do with regards to orthognathic surgery?
Provide occlusal wafer to guide surgery
Building 3D skull models
Digital predictions of final occlusion
What is the role of the orthodontist in orthognathic surgery?
Early recognition of dento-facial abnormalities
Orthodontic preparation of the dentition before and after surgery.
Follow up.
What is the role of the surgeons in orthognathic surgery?
Surgically move the jaws into the right position.
What aspects of the history are important to find out from someone when considering them for orthognathic surgery?
Does anyone else in your family have jaws like this?
If it is not genetic then think about what else it could be
- Condylar hyperplasia
- Cysts
- Acromegaly
- Trauma
Determine the motivation of the surgery and what they don’t like about their jaws.
What aspects of the E/O examination would you want to check?
Look from the front- is the face symmetrical? Look at vertical symmetry and horizontal symmetry.
Lip and nose morphology- upper lip and lower lip should touch- oral seal.
A-P relationship- relationship of the maxilla and the mandible to the anterior cranial base and also to each other.
Skeletal relationship- Class I, II or III
What aspects of the I/O examination would you want to investigate?
General dental examination
Smile line
Crowded/spaced/misaligned in the upper and lower dentition
Incisor classification
Canine classification
Molar classification
Overbite
Overjet
Inclination of upper and lower incisors
Centre line discrepancy
Tongue size, mobility, speech pattern.
What special investigations might you opt to do?
Radiographs- OPT, PA, lateral ceph
CBCT- tells us the shape of the mandible and the maxilla in 3D
Study models
Clinical photographs
Stereophotogrametry- 3D photographs, use an intra-oral scanner for this.
What are study models used for in orthognathic surgery?
Study occlusion
Orthodontic analysis
Orthognathic surgery planning
Occlusal safer for surgery
Assess surgical changes
Assess long term stability/relapse
What diagnosis might someone have that might be helped with surgery?
Maxilla
- Retrognathic
- Prognathoc
- Vertical excess
- Vertical deficiency
- Narrow or wide maxilla
Mandible
- Retrognathic
- Prognathic
Chin
- Progenia
- Retrogenia
What options can you give to the patient?
Orthodontics alone
Orthodontics and surgery
Surgery alone
What would the orthodontics and surgery combination involve?
Pre-surgical orthodontics- decompensated the incisors, align the teeth, co-ordinate the arches.
Surgery to correct the jaw position.
Post-surgery orthodontics for fine tuning.
What type of surgery might be needed to correct the position of the maxilla?
Le Fort I osteotomy
- Disarticulate the maxilla from the base of the skull and move it to pre-planned position using the surgical wafer and fix in place with plates and screws.
- Can move the maxilla forwards, downwards and upwards but not backwards because of the pterygoid plate.
Anterior maxillary osteotomy- this surgery is to move the maxilla backwards.
What surgical techniques might be employed for the mandible?
Sagittal split mandibular osteotomy- this is advancement surgery.
- Separate the ramus from the body of the mandible- movie the body of the mandible in any direction that you want.
- Then fix in place with plates and screws.
Sagittal split osteotomy- set the mandible back.
VSSO- set the mandible back
What surgery might you employ for the chin?
Genioplasty- Advancement, set back, rotation, reduction.
