Small Animal Dental Care Guide | Prevention and Treatment of Malocclusion

For small animals such as rabbits, hamsters, guinea pigs, chinchillas, and degus, dental health is a critical issue directly linked to their survival. These animals have teeth called "continuously growing teeth" (hypsodonts) that grow throughout their lives, and neglecting proper care leads to serious dental problems called malocclusion.

How Continuously Growing Teeth Work

Understanding that small animal teeth are "continuously growing teeth" that never stop growing throughout their lives is an essential point that every keeper must grasp as a basic aspect of care.

Rabbits have continuously growing teeth in both their incisors (front teeth) and molars (back teeth), growing at a rate of about 2mm per week. In hamsters, only the incisors are continuously growing teeth; molars do not grow. Chinchillas and degus, like rabbits, have continuously growing incisors and molars. Guinea pigs also have continuously growing teeth throughout their dentition.

In a normal state, proper wear is maintained and a consistent tooth length is preserved as the upper and lower teeth occlude properly. When this natural process—whereby hard foods are chewed and teeth wear down naturally—breaks down, teeth grow excessively and cause malocclusion.

What Is Malocclusion?

Malocclusion refers to a state in which the bite is not normal. It is a condition in which teeth grow in abnormal directions or the upper and lower teeth no longer occlude properly.

Incisor malocclusion: A condition in which the front teeth grow excessively so the mouth cannot close, or they grow bent inward or outward. This is a symptom that owners can easily notice since it is visually apparent from the outside.

Molar malocclusion: Molar malocclusion is difficult to see from the outside and often goes undetected for a long time. Molars may grow at an angle and injure the cheek or tongue, or tooth roots may extend and compress the jawbone or tear duct. For rabbits, molar malocclusion is particularly serious.

Causes of Malocclusion

The causes of malocclusion can be divided into genetic and environmental factors.

Genetic factors: Some individuals have jaw structures genetically predisposed to malocclusion. In particular, short-headed rabbit breeds such as Netherland Dwarfs and Holland Lops tend to have dental problems due to their short jaw structure. The skeletal differences among rabbit breeds are also discussed in the Rabbit All-Breed Comparison Guide.