Development of the Occlusion Flashcards
Name 2 reasons a knowledge of development of dentition is important
- Prediction of future need for treatment
2. Early diagnosis may enable interceptive treatment
Name 3 key stages of development of the occlusion
- Primary dentition
- Mixed dentition
- Permanent dentition
What is mixed dentition?
Transition period between primary and permanent dentitio
What are 3 stages of tooth development?
- Bud
- Cap
- Bell
Name 3 key points of primary dentition
- Eruption times vary by 6 months from expected ages
- Calcification begins 4-6 months in utero
- Root formation complete 12-18 months after eruption
Describe the sequence of eruption of primary teeth
a - b - d - c - e
What are 4 notable points with regards to the sequence of eruption of primary teeth?
- b-c-d earlier in maxilla than mandible
- Girls erupt faster than boys
- 6 month variation is normal
- No significant left and right differences
What are the eruption dates of primary central incisors in maxilla and mandible?
10 months - 8 months
What are the eruption dates of primary lateral incisors in maxilla and mandible?
11 months - 13 months
What are the eruption dates of primary cuspids in maxilla and mandible?
19 months - 20 months
What are the eruption dates of primary 1st molars in maxilla and mandible?
16 months - 16 months
What are the eruption dates of primary 2nd molars in maxilla and mandible?
29 months - 27 months
Describe 2 changes which may occur between 2.5 and 5.5 years
- Increase in spacing due to increase in arch width
2. Occlusal attrition can lead to edge-to-edge incisal relationship
Name 6 things to check for when examining a primary dentition
- Spacing
- Crossbites
- Overjet
- Overbite
- Early loss
- Incisor trauma
Why is spacing important to check for in primary dentition?
No spacing indicates permanent dentition likely to be crowded so interceptive orthodontic treatment may be required
Why are overjets and overbites important to check for in primary dentition?
May be due to skeletal defect and important to ensure these patients are under review
Name 2 causes of an open bite
- Thumb sucking
2. Pacifier sucking
Why is incisor trauma important to check for in primary dentition?
It can lead to permanent dentition being dilacerated where the crown is displaced but root is not
Describe the arch length prediction from alignment of primary teeth and the likely permanent outcome
Primary crowding - Almost certain extractions
No primary spacing - Possible extractions
Fair spacing - Mild to moderate crowding
Good spacing - No or mild crowding
Excess spacing - No crowding / Excess spacing
What 2 permanent teeth are most likely to erupt first?
- 1st molars
2. Lower central incisors
What 2 permanent teeth are most likely to erupt first?
- 1st molars
2. Lower central incisors
What 2 permanent teeth are most likely to erupt first?
- 1st molars
2. Lower central incisors
Name 6 things to check for when examining a mixed dentition
- Ankylosis
- Carious first molars
- Early loss of deciduous molars
- Ectopic eruption of maxillary canines
- Eruption failures
- Missing / extra teeth