Week 5- Space Management Flashcards
What is the difference between balancing and compensating extractions?
- Balancing: extraction of contralateral tooth (opposite tooth of same arch)
- Compensating: extraction of opposing tooth in opposite arch
What can happen if a deciduous canine is lost before the other canine? What can you do to avoid this issue?
Midline can shift. Consider balancing exo (extract the other deciduous canine in same arch)
What is the issue with timing of crown formation and timing of eruption for 6’s?
- 6’s crowns form around birth and are susceptible to hypomineralisation/hypoplasia.
- Timing of eruption makes teeth vulnerable to caries as they are in the mouth before children establish good OH
What is a treatment option if the first permanent molar has poor prognosis in children?
Aim to get 2nd molar to erupt as replacement for 1st molar and 3rd molar to erupt as replacement for 2nd molar. (2 functioning molar teeth each side of arch)
What should be considered if you are extracting 6 due to poor prognosis?
Consider compensation extraction. Otherwise tooth could over erupt.
When should a 6 be extracted if it has poor prognosis to allow the 7 to fill its space?
Mx: timing not as important (8-10)
Md: extract 6 immediately after calcification of bifurcation of md 2nd molar.
Where is primate/anthropoid spaces for upper and lower arch?
M to upper deciduous canine and D to lower deciduous canine
What is the incisor liability for upper and lower arches?
Upper: 7.5mm
Lower: 6mm
How can you overcome incisor liability in maxilla?
- Anterior interdental space
- Primate space
- Labial eruption of incisors increasing arch length and circumference
- Increased inter-canine width
- Reduced inter-incisal angle (more proclined, making more space)
How can you overcome incisor liability in mandible?
- Anterior interdental space
- Increased inter-canine width
- Reduced inter-incisal angle
Can you use Angles classification in the primary dentition?
No
What are the 3 deciduous molar relationships?
- Flush terminal plane: distal surface of md and mx molars are in same vertical plane
- Mesial step: distal surface of md second molar is mesial to distal surface of mx molar.
- Distal step: distal surface of md second molar is distal to distal surface of maxillary second molar.
What is the most common molar relationship in deciduous dentition?
Fulsh terminal plane
How do we transition from flush terminal plane to class I occlusion?
- Early shift
- Late shift
- Differential jaw growth
(or combination)
What is early shift?
If md primate space is available during eruption of permanent molars, the lower permanent molar move forward into a class I relationship.
What is late shift?
Uses leeway space. There is space difference between posterior primary teeth and permanent teeth which replaces them.
What is differential jaw growth?
If lower jaw grows more forwards (than mx) the lower jaw carries the lower teeth further forward relative to upper teeth.
If you lose primary incisors at a young age, what can you use?
No tx necessary. Replacement is for aesthetic concerns mainly. Can make fixed lingual arch off deciduous second molars.
What should you do if you have premature loss of primary canines?
- Balance extractions
- Lower lingual arch can prevent space loss caused by retraction of incisors.
What are the pros and cons of band and loop appliance?
- Pros: Can be used prior to eruption of permanent incisors & can be fabricated and placed chairside at same visit
- Con: if abutment tooth is lost, the appliance fails.
What is the issue with the following pic?
E’s lost early and 6’s moved forwards
What is happening in this picture?
LHS deciduous canine lost before RHS side, causing shift in midline. Should have balanced earlier.
What is a lingual holding arch?
- Bands on 6’s
- Wire rests on lingual surface of anterior teeth
What is wrong with this tx option?
Already lost space of E. Needed to place earlier.
