15. Retention Flashcards
What are the three things we want to balance to prevent an ortho case from relapsing
teeth
bone
muscle
Define retention
holding of teeth in ideal esthetic and functional positions
Causes of relapse are
- Unfavorable growth pattern may return
- Incorrect placement of teeth relative to basal bone (esp. lower anterior teeth too far anterior)
- Incorrect arch form relative to muscle function
- Lack of normal proximal contacts (tipping)
- Incorrect relationship inclined planes
- Continuation causative factors (i.e habits)
- Perio factors move teeth to move teeth to former positions
- Tooth size discrepancies
- Eruption of third moalrs
- Local hereditary characteristics (Growth factors in cell metabolism/ local tissue conditions may cause relapse tendency forever)
- Individual variations (chewing, speaking, lip/tongue/cheek)
Over-extension is resisted by _ and over contraction is resisted by _
cheeks and lips… tongue
(overjet/overbites) have the tendency to return
overbite
Periapical fibers in perio membrane rearrange how often
8-10 weeks
Alveolar crest (supra-alveolar) elastic fibers rearrange how often
1 yr
The teeth should be held in their position until what happens
fibrous tissue rearranged and bone fully calcifies
What are the limits of labial movement for the mandibular incisors
2 mm
What is the limit of lateral movement of the mandibular canines
0 mm
What is the limit of lateral movement of the mandibular 1st PM
1-2 mm
What is the limit of lateral movement of the mandibular 2nd PM
2-3 mm
What is the limit of lateral movement of the mandibular 1st molar
2-3 mm
What are the different intra-alveolar fiber bundles between the root and cortical plate
- Crestal
- Horizontal
- Oblique
- Apical
What is an example of hereditary characteristics that can cause relapse tendency forever
maxillary laterals in class II division 2
Most ortho cases have (no retention/limiteds retentio/semi-permenant/permenant retention)
limited retention
What are the different requirements of retainers
- Restrain teeth in current (moved) positions
- Allow functional forces to act freely
- Hygenic (smooth, polished and no porosities)
- Inconspicuous and strong
What are the different types of retainers
Removable
-Hawley and variations
Fixed
-Mandibular cuspid to cuspid (like a splint)
Headgear
-May be worn with retainers above in skeletal discrepancies till the end of growth
Impressions for retainers should be made (before/after) the removal of fixed appliances
before
How long should the patient wear their retainer full time
1 month after braces removed
After the first month post-treatment how many hours should the retainer be worn for and for how long
18 hrs…3 months
Describe the retainer schedule
Full time --> 1 month 18 hrs --> 3 months 12 hr --> 3 months 8 hrs --> 3 months Alternate Nights --> 3 months 2-3 nights/week --> forever
Why are corrected anterior and posterior cross bites no retention
become open bites
Teeth separated with regainers to allow the eruption of blocked teeth is an example of (no retention/ limited retention/semi-premanent retention)
no retention
