Maxillary Expansion Flashcards
Diagnosis to expand
-narrow palatal vault (easily assessed using casts)
-transpalatal width of 31 mm or less is likely to require expansion
-Transverse deficiency
Transverse deficiency
Crossbite, crowding, laterally flared posterior teeth, dark spaces at the corners of the mouth
Etiology
-environmental and genetic factors
-airway difficulties
-digit habits
Airway difficulties
Promote mouth breathing —> tongue in floor of mouth —> no pressure from tongue on maxilla to expand it
Digit habits
Buccinator muscle creates inward force
3 methods for expansion
-split removable plate with jack screw or heavy midling spring
-lingual arch —>quad helix, W-arch
-fixed palatal expander with jack screw
Primary/early mixed dentition
-use quad helix (100g force)
-jack screws can accidentally be activated too rapidly and distort facial structures
Late mixed dentition
4 band RPE
2 band RPE
Include as many teeth as possible
Exo case- delay extraction of premolars
4 band RPE
Severe anterior crowding and a tapered arch form
2 band RPE
Mixed dentition with mild crowding
Rapid activation of jackscrews
0.5 mm per day
10-20 lbs of pressure
Semi rapid activation of jackscrews
0.25 mm per day
Slow activation of jackscrews
1 mm per week
2 lbs of pressure
______ can provide same ultimate result over a 10-12 weeks as RPE with less trauma to teeth and bones
Slow
Effects of palatal expansion
Separation of palatal suture is non parallel
Stresses are concentrated in the anterior and progress to the posterior (can get diastemas, posterior maxilla has more attachments)
Wedge shape separation from frontal view
Effect on mandinle of palatal expansion
Mandibular teeth often upright
Inter molar and inter canine distances increase
Expand until maxillary ______ cusps occlude with ________ inclines of buccal cusps of mandibular molars
Lingual, lingual
Retain for _____ months using the appliance
4-6 months
What to do when appliances arent enough
Suture closure
Treatment options - SARPE/SARMe, multiple piece Lefort I
Sutural considerations
Major area of resistance to expansion is not just the midpalatal suture
-frontomaxillary, zygomaticofrontal, zygomaticomaxillary, zygomatic temporal sutures
SARPE indications
-Transverse maxillary deficiencies > 5 mm in skeletally mature pt (<5 mm can be camouflaged by the ortho)
>-7 mm discrepancy —> SARPE definitely indicated (more stable and vascularity is not compromised as in segmentalized LeFort osteotomies
- if extractions are not desired prior to surgery
-pt with arch length discrepancies and maxillary incisors in an acceptable vertical and sagittal position are ideal
SARPE vs Lefort I
-SARPE= more stable in transverse
-Risk of perio defects, relapse and compromised blood supply are reduced with SARPE
-Lefort require alignment of teeth/tipping of roots prior to surgery and often extractions
