The reasons why dogs’ permanent teeth grow in and their deciduous teeth do not fall out:

1. If a dog is deficient in calcium during tooth replacement, it will cause its teeth to grow slowly and its deciduous teeth will not fall out. At the same time, permanent teeth also grow slowly. Calcium deficiency can also cause the enamel layer to be thin and the structure to be unstable. The permanent teeth cannot push out the deciduous teeth, so the dog's deciduous teeth have not fallen out.

2. The food that breeders feed their dogs is too soft and cannot help the dogs loosen their deciduous teeth. The strong deciduous teeth cause the permanent teeth to grow out of place.

Methods to avoid double rows of teeth in dogs:

1. Breeders should feed dogs food during the teething period, and do not feed them soft food. , so that the dog’s deciduous teeth can be loosened when eating.

2. Breeders should pay attention to supplementing calcium for dogs during the teething period. This will allow the permanent teeth to grow normally and push out the deciduous teeth.

3. The breeder can provide the dog with some teething toys to help the dog loosen the deciduous teeth when the breeder interacts with the dog, but attention must be paid to prevent the deciduous teeth from breaking.

4. Breeders can often massage the dog’s teeth, which will also help the loss of deciduous teeth.

5. If the dog’s deciduous teeth have not fallen out after one year of age, the breeder can take the dog to a professional pet hospital for examination and a veterinarian for tooth extraction.