1. Occlusion
CTVT pgs
Orthodontics studies the way in which the teeth meet each other.
Occlusion- the normal position of the teeth in the mouth
Easier to assess when the mouth is closed
In normal occlusion, teeth come together in a __________ bite.
Should be assessed during the initial oral examination

2. Scissors Bite

3. Scissors Bite Evaluation
Three locations:
1. The mandibular canine tooth resides in the ________________ space of the maxillary third incisor and the maxillary canine.
2. The maxillary fourth premolar occludes _________ to the mandibular first molar.
These two teeth together, constitute the ___________ teeth.
3. Maxillary incisors are slightly ___________ to the mandibular incisors.
Mandibular incisors should rest on the ___________ of the maxillary incisors

4. Normal Scissors Occlusion: When all three locations are normal- the premolars interdigitate toward the opposing interdental space.

5. Malocclusion
“Orthodontic Probs”
Malocclusion is an abnormality in the way the teeth occlude
Can occur in any of the three head shapes, but is more common in _________________ breeds.

6. Malocclusions There are four classes of malocclusions.
Class I- one or more teeth is in an abnormal position
Easily fixed with orthodontic correction OR not needed
Examples: Rostral Cross-bite and Caudal Cross-bite
Class II-IV are skeletal malocclusions due to differing jaw lengths
Why are we concerned with maloccluded teeth?

7. Class I: Rostral Cross-bite
Maxillary incisors are ________ to the mandibular incisors.
Canines are in their normal location!
Possible causes:
Treatment:
Orthodontic movement or extraction of the abnormal teeth.
Treat vs. not treat?

8. Rostral Cross-bite

9. Rostral Cross-bite

10. Class I: Caudal Cross-bite
Maxillary premolars/molars are positioned _______ to the mandibular opposing premolars/molars
Occurs occasionally in
____________ breeds
Treatment:

11. Class I: Lance Canine Maxillary canine tooth is displaced __________.
Eastcott referrals

12. Class II: Mandibular Distoclusion
Maxillary prognathism OR mandibular brachygnathism
Mandible is _________ than normal
Referred to as “overshot”
Never an accepted standard!
Concerns:
Debris is not removed from teeth during normal chewing
Hard palate trauma

13. Class III: Mandibular Mesioclusion
Mandibular prognathism OR maxillary brachygnathism
Mandible is _________ than normal
Referred to as “undershot”
The mandibular canines sit _______ to the maxillary 3rd incisors
Concerns:
Teeth lose some of their self-cleaning ability
Maxillary teeth can traumatize soft tissue
*Accepted as normal in _____________ breeds!

14. Mandibular Mesioclusion

15. Mandibular Mesioclusion

16. Wry bite Unilateral __________ of the jaw
A one-sided brachygnathic bite forms
Jaw curves toward the shorter side
In more severe cases, animal appears to have a crooked head

17. What Do You See Here?
Persistent deciduous teeth

18. Persistent Deciduous Teeth
CTVT pg 1260
A deciduous tooth that remains after the permanent tooth has already erupted
Most common in the ______ breeds
Concerns:
1. Interfere with normal eruption pathway of permanent teeth  ____________ & ____________
Early detection is key!
When should this be discussed with client?
2. Are a reservoir for debris  ________ ________

19. What numbers are these persistent teeth?
Describe the spatial positioning of the permanent canine:

20. Persistent Deciduous Teeth
Treatment:
Interceptive Orthodontics
Tooth should be removed as a whole
Possible complications:
Iatrogenic damage to:
permanent tooth
surrounding soft tissue

21. Polydontia
Supernumerary teeth should not be confused with persistent deciduous teeth.
These are extra ___________ teeth
Concerns:
Crowding
Attrition
Treatment: extraction

22. Hypodontia One or more teeth do not form in the dental arcade.
Un-errupted permanent tooth or hypodontia?
How do you confirm?
If permanent tooth is absent, a deciduous tooth can remain in the arch for months to years.
No treatment necessary