Occlusion CTVT pgs 1220-1222 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

Scissors Bite

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

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

Malocclusion 1258-60 “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.

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?

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?

Rostral Cross-bite

Rostral Cross-bite

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

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

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

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!

Mandibular Mesioclusion

Mandibular Mesioclusion

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

What Do You See Here? Persistent deciduous teeth

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  ________ ________

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

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

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

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