Losing Deciduous Teeth
Puppies usually lose their deciduous teeth (baby teeth) around 4 to 7 months of age; this is a normal process. If you have a puppy missing teeth, it maybe that he is just getting his permanent teeth in.
Genetics
Some dog breeds are born without a few teeth. Breeds such as the Doberman Pinscher and the Collie are commonly affected.
Periodontal Disease
Periodontal disease can cause gingivitis, and loss of bone and soft tissue surrounding the tooth. If not treated, periodontal disease can lead to damage of the jaw bone and the subsequent loss of teeth.
Embedded Teeth
Embedded teeth are teeth that did not erupt during the normal teething process and remain under the gum. Embedded teeth are more common is small dog breeds but may occur in any breed.
Hormone Loss
Hormone loss in a dog’s body can lead to decreased bone mineral content and strength. This can weaken the tooth anchorage and can increase the chances of developing periodontal disease.
Canine Distemper as a Puppy
Canine distemper is a very serious disease which is often fatal. Canine distemper can cause the destruction of the cells responsible for producing tooth enamel. Therefore, if your dog survived the distemper virus, his teeth may be more susceptible to erosion.
Chewing on Rocks
Strange as it may sound, some dogs like chewing on rocks. It may be that he was starved as a puppy and learned to eat anything he could find. It may also be out of boredom or wanting attention. Regardless of the reason why your dog chews on rocks, biting rocks will fracture and break off his teeth.
Wrong Chew Toys
There are some chew toys that can cause your dog’s teeth to crack and fracture. Hooves, antlers and bones are too rigid and will cause damage to your dog’s teeth. Compressed rawhides can also fracture teeth; they also cause choking. On a side note, compressed rawhides not made in the USA may have toxic compounds and chemicals.