Tx Class I Malocclusion Flashcards
What is class I incisor relationship?
Lower incisor occlude at or below the cingulum plateau of upper incisor
What are problems in class I relationship?
Crowding, spacing, displaced teeth
Can’t have overbite
How is crowding caused?
Imbalance jaw size and tooth size
Tx of crowding?
Expansion, distal movement, enamel stripping, XLA
What are problems with expanding?
Relapse, fenestration of labial plate, aesthetic
Don’t expand lower arch - prone relapse - get average 3.7mm expansion but 2mm relapse
How expand upper arch?
Removable or fixed appliances
What is quad helix?
URA
Bands on molars and arms on premolars
Quad sits roof of mouth
Activated out of mouth
What is Damon system?
Expanded - self ligating
What is the limits of expansion?
Buccal segments - stable up to 3mm
What is fenestration?
Roots moved out of bone - risk of overexpansion
Why use distal movements?
Use distal movement of buccal segments - retract 6s to help align anterior displacement
How get distal movement in upper arch?
Headgear
Non-compliance appliances (e.g pendulum/ distal jet)
Temporary anchorage device - screwed into bone under LA
How to get distal movement lower arch?
Lip bumper - doesn’t work - supposed to move via forces from soft tissue
What pt are suitable for distal movement of upper buccal segments?
Co-operative pt
Half unit class II molars
Well aligned lower arch
What is enamel stripping?
Interprxoimal reduction using abrasive metal strips/ air rotar
Remove up to 0.25mm enamel from contact point
Alignment after stripping
What problems can spacing cause?
Upper midline diastema, generalised spacing
Problem closing midline diastema?
Prone relapse - need bonded retainer
How is generalised spacing causes and how would tx?
Jaw too big or teeth too small
Open space - restorative replacement (bridge/ implant)
Close space
General rules for opening and closing space with incisors?
Class II - close space
Class III - open space (want to bring incisors forward)
What is the most common displaced tooth?
Upper permanent canine (85% palatal impaction, 15% buccal impaction)
How tx maxillary canine?
Buccal impaction - closed exposure/ open exposure
Palatal impaction - leave in situ, extract, expose and align or transplant
Summary tx class I w/ crowding?
- Expansion
- Distal movement
- Enamel stripping
- XLA
Summary tx class I w/ spacing
Open or close space
Summary tx class I w/ displaced teeth?
- Leave
- Extract
- Expose and align
- Transplant
