In general, the distribution of permanent teeth in adult dogs: 6 upper and lower incisors, 2 upper and lower ages, 8 upper and lower premolars, 4 upper and 6 lower premolars, 42 in total. The number and distribution of the young dog’s deciduous teeth: 6 in the upper and lower incisors, 2 in the upper and lower canine teeth, 6 in the upper and lower premolars, a total of 28. The age of adult dog is the most obvious in the growth, wear, sharpness and dullness of teeth. We can judge the age of puppies from the number of teeth, strength, new and old, brightness and other aspects.
The dog’s age was roughly determined according to the following criteria: The teeth gradually grew out irregularly in about 20 days. For 30-40 days, the teeth of the primary incisors are well aligned. After 2 months, all the teeth were long and neat, thin and tender white. 2-4 months, replace the first primary incisor. 5-6 months, replace the second and third primary incisors and all primary canine teeth. Over 8 months, all the teeth are replaced with permanent teeth. 1-year-old, the permanent teeth are neat, smooth and firm, and the upper part of the incisor has a sharp process. At the age of 1.5, the peak of the first mandibular incisor was obliterated. At the age of 2.5, the peak of the second mandibular incisor was obliterated. At the age of 3.5, the peak of the first maxillary incisor disappeared. At the age of 4.5, the peak of the second maxillary incisor disappeared. At the age of 5, the peak of the third mandibular incisor was slightly worn, while the first and second mandibular incisors were grinded in a rectangle. At the age of 6, the third incisor of mandible was sharpened and the canine teeth were blunt and round. At the age of 7, the first incisor of mandible was worn to the root of tooth, and the worn surface was oval. At the age of 8, the first mandibular incisor was worn and tilted forward. At the age of 10, the worn surfaces of the second mandibular and the first maxillary incisors were oval. 16 years old, incisor off, canine incomplete.