JVD 2019 #4 Prevalence of Malocclusion of Deciduous Dentition in Dogs: An Evaluation of 297 Puppies; Hoyer + Rawlinson

Question 1

How many puppies (8 to 12wk) were identified as having a malocclusion in the 1-yr study period?

Answer 1

26% (77 of 297 puppies)

* dogs of breeds with MAL3 ‘normal’ considered normal for study

Question 2

Was a significant difference in prevalence noted between purebred and mixed breed dogs?

Answer 2

No significant difference in prevalence.
But in single dogs (not litters) purebreds had a significantly higher percentage of malocclusion compared to mixed breeds 33.8% and 20% respectively. The opposite was true in puppies presented as litters- none in purebred and 23.5% in mixed breed litters

Question 3

What was the most common malocclusion class 1 (MAL1)?

Answer 3

MAL- linguoversion of one or both decid MN canines (11/12, 92%)
Caudal crossbite considered MAL1

Question 4

Embryologically, where do the bones of the maxilla and mandible result from?

Answer 4

Development of the first brachial arch, which are organizations of migrating neural crest cells in the developing embryo

Question 5

What kind of bone growth does the skull primary display?

Answer 5

Intramembranous ossification- direct formation of bony matrix within existing connective tissues

Question 6

When does mandibular growth occur in the rostral mandible?

Answer 6

Very early in development, after approx day 50 (week 7) all growth is from caudal to the 1st molar in the area of the condyle

Question 7

Where does maxillary bone growth occur

Answer 7

at the incisive-maxillary and palatal-maxillary sutures. The contribution of the length of palatal bones decreases with age and the comparative length of the incisive and maxillary bones increases with age.

Question 8

What growth disruption causes disparity of the maxilla and mandible of brachycephalic dogs?

Answer 8

Primarily chondrodystrophic arrest of the bones of the maxilla and likely develops between the 8-12 weeks and facial maturity