12. Extractions Flashcards
Know eruption patterns for canines and bicuspids on mandibular and maxillary arch
Maxilla
-1st PM – 2nd PM – canine
Mandible
-Canine– 1st PM– 2nd PM
Serial extraction purpose
- Disrupt usual eruption sequence (want the 1st bicuspids on lower arch to come in before canines)
- Extract in early mixed dentition to avoid crowding in permanent dentition
- Facilitates fixed appliance therapy later
Contraindications for serial extraction
- Class II or III
- Skeletal discrepancy
- Deep overbite (need maxillary Hawley and baseplate)
- Imbalance perioral musculature (strain, hypo/hypertonicity)
- Habits
Want at least _ mm of crowding for serial extractions
10 mm
Sequence of serial extractions
- Extract all deciduous canines
- Extract deciduous 1st molars
- Extract 1st bicuspids
Why extract the deciduous canines
-eases anterior crowding
Extraction of the deciduous first molars benefits the (maxillary/mandibular) arch
mandibular
Why extract the 1st bicuspids
-permanent canines drift distally into extraction sites
Benefits of serial extractions
- Naturally induced alignment severely crowded anterior teeth
- Improved periodontal health
- Improved cosmetics/psychological state
- Facilitates fixed appliance workload
- Less possible orthogenic damage
T/F anchorage units tend to move
t
Which is more difficult maintaining tooth position or moving teeth
maintaining
Difference between intra-oral and extra-oral anchorage
intra= anchorage inside the mouth Extra= outside mouth
Cervical, occipital and parietal are…
down, horizontal and high pull
Facial includes what extraoral features
forehead and chin
Intra-oral anchorage types are
- Simple
- Stationary
- Reciprocal
Describe simple, stationary and reciprocal anchorage
- Simple= tooth may tip
- Stationary= tooth may only move bodily (translate)
- Reciprocal= both units move equal amounts in opposite directions
Structures for intra-oral anchorage are
- Teeth
- Basal bone and overlying soft tissue
- Cortical bone plates
Characteristics of teeth that make good anchors are
- Root form
- Root size and number
- Root length
Root form of
- bicuspids
- Mand. incisors
- Canines
- Max. centrals
- bicuspids= round
- Mand. incisors= flat
- Canines= triangular
- Max. centrals= triangular
Increased root surface = (increased/decreased) stress resistance
increased
Basal bone and soft tissue that can be used for anchorage includes what structures intraorally
- hard palate (i.e nance)
- Lingual surface of mandible
T/F cortical plates facilitate tooth movement
f- resists tooth movement. cancellous bone supports tooth movement
TADs stands for
temporary anchorage device
Another word for TADs is
orthodontic microimplants
