Ortho - Lecture 15: Tx Considerations in Orthognathic Surgery Flashcards
What should you consider?
Age of pt
Type & severity of skeletal problem
What are the options?
Growth modification
Camouflage
Ortho surgery
What is the indication for surgery?
Tx objectives and goals that are outside the range of ortho possibility, which changes w/ age
Which surgical stability has the following limitations?
Less stability after 8 mm of advancement
Rotational pattern makes a difference
Mandible forward
Which surgical stability?
Most successful mandibular advancement: short face w/ rotation of chin down
Mandible forward
Which surgical stability has the following limitations?
The longer the move, the less stable
Maxilla forward
Which surgical stability?
Forward + down is often desired
Maxilla forward
Which surgical stability?
Maxilla surgery = best way to tx class III
Maxilla forward
Which surgical stability has the following limitations?
Difficult to control ramus inclination at surgery
Mandible back
Which surgical stability has the following limitations?
Limited by muscle force and soft tissue stretch
Maxilla down + wider
Orthodontic preparation for surgery must include removal of dental compensation for the skeletal deformity. What is this step called?
Decompression
T/F: Orthodontic preparation for surgery often is the reverse of conventional orthodontic treatment, so it’s important to make pts aware that things will get worse before they get better
True
Which ext pattern?
Ext mandibular premolars
Decompensates flaring of lower incisors
Increases mandibular surgical movement
Finish with Class III molars
Class II
Which ext pattern?
May be necessary to extract LOWER premolars or use Class III elastics
Class II
Which ext pattern?
Ext maxillary premolars
Decompensates flaring of upper incisors
Increases maxillary surgical movement
Finish with Class II molars
Class III
Which ext pattern?
May be necessary to extract UPPER premolars or use Class II elastics
Class III
Will the following increase or decrease facial height?
Mandibular osteotomy
Rotate chin down
Increase facial height
Will the following increase or decrease facial height?
Maxillary LeFort osteotomy (impaction)
Rotate chin up
Decrease facial height
Open bite or deep bite?
Post-surgical leveling
If exts are done, some ext space is left open prior to surgery
After surgery, the pt’s significant posterior open bite is closed using vertical elastics
This increases the lower facial height
Deep bite
Open bite or deep bite?
Pre-surgical leveling or surgical assisted leveling
Tends to make the open bite significantly worse prior to surgery
This allows the surgeon to establish the proper vertical dimension on the pt during surgery
Open bite
List the hierarchy of surgical stability from most to least stable (8)
Maxilla up
Mandible forward
Maxilla forward
Maxilla up + mandible foward
Maxilla forward + mandible back
Mandible back
Maxilla down
Maxilla wider
What 4 things should you do before surgery?
Intrusion
Establish incisor position
Obtain arch compatibility
Everything necessary so set it up for finishing in 6 months post-surgery
T/F: As a general rule, it should not take more than a year to get a patient ready for orthognathic surgery
True
What 2 things can wait until after surgery?
Extrusion (leveling)
Root paralleling
When is the pt ready for surgery?
When the orthodontist thinks the patient is ready for surgery!
T/F: It’s important for the orthodontist to see the results of the model surgery because details of occlusion that make no difference to the surgeon can greatly affect time in finishing/post-surgical orthodontics
True
Less reliance on surgeon’s judgement as to placement in the operating room and less pre-surgical orthodontics needed
Surgical splint
Is a thin or thick surgical splint preferred?
Thin
Goal is to prevent tooth movement
Stabilizing archwires
What are the post-op expectations?
Lots of swelling
Short-term paresthesia of infraorbital nerve (maxilla) and IAN (mandible)
Significant pain is uncommon due to paresthesia
Usually, 1 overnight hospital stay per jaw
Which mandibular technique?
Advantages = lower incidence of nerve injury
Disadvantages = requires maxillomandibular fixation (MMF); setback only
Intraoral vertical ramus osteotomy (IVRO)
Which mandibular technique?
Advantages = versatility; maxillomandibular fixation usually not necessary
Disadvantages = nerve injury
Bilateral sagittal split osteotomy (BSSO)
Which mandibular technique?
Osteotomy versus implant
Osteotomy is highly versatile allowing for movement of the chin in all directions
Implant can only augment chin
Reports of bone resorption under implants
Genioplasty
Which maxillary technique?
High degree of versatility (can move superior, inferior, anterior, posterior)
Movements limited by anatomic structures, soft tissues
Large movements require grafting
Dental injury is rare if osteotomy is kept 5mm above apices
May be segmented into 2-3 pieces
LeFort
What do the following surgery choices do?
- Surgically-assisted rapid palatal expansion (SARPE) followed by LeFort osteotomy
- Segmental LeFort osteotomy
Widen maxilla
Which has better stability, SARPE or Segmental LeFort?
SARPE
Which has only one surgery and the amount of expansion is limited by soft tissue, SARPE or Segmental LeFort?
Segmental LeFort
1 or 2 jaw surgery?
Indications = deformities in both maxilla and mandible or deformity in one jaw requiring a large, unstable movement
2 jaw surgery
Which adjunctive procedure?
Excess skin -> upper eyelids, bagginess -> lower eyelids
Blepharoplasty
Which adjunctive procedure?
Reduce prominence of ears
Otoplasty
Which adjunctive procedure?
Cosmetic nose surgery
Rhinoplasty
Which adjunctive procedure?
Complete facelift for deep wrinkles
Rhytidectomy
Which adjunctive procedure?
For fine wrinkles
Laser resurfacing
