Tooth resorption is a disease in which specialized cells (odontoclasts) destroy the hard tissues of the tooth — enamel, dentin, and cementum. The disease affects both cats and dogs and is far more common than many owners realize. In cats, the prevalence is 20–67%, rising to as high as 75% in cats over 5 years old. In a Finnish study of 8,115 cats, purebred cats were clearly more susceptible (70%) than mixed-breed cats (38%). In dogs, the prevalence is similarly significant: full-mouth radiographs revealed tooth resorption in up to 54% of dogs, with the risk increasing particularly at 9–11 years of age. In both species, the premolars are the most commonly affected teeth. The disease is particularly insidious because both cats and dogs hide oral pain — many pets eat and behave "normally" despite significant chronic pain.
Types — Why Radiographs Determine Treatment
Tooth resorption is divided into three types, and distinguishing between them always requires dental radiographs. In Type 1, the tooth is destroyed locally and inflammatory granulation tissue replaces the lost tooth — radiographs show dark areas, but the roots and periodontal ligament are still identifiable. In Type 2, the root is replaced by bone and fuses with the jawbone (ankylosis) — on radiographs, the roots appear as "ghosts" or disappear entirely into the surrounding bone. Type 3 shows features of both in the same tooth. Type 2 is more common and its cause is considered unknown. Type 1 is often associated with local inflammation.
Symptoms — Hidden Pain
Tooth resorption is often a "silent disease" — animals have evolved to hide oral pain, because in nature showing pain makes an animal prey. Owners may notice subtle signs: dropping food from the mouth, tilting the head while eating, chewing on only one side, swallowing without chewing, increased drooling, jaw trembling or chattering (muscle spasms when the lesion is touched), avoiding hard toys or bones, irritability, withdrawal, or a deteriorating coat. Many pets continue eating despite pain. During clinical examination, pink spots on the gums may be seen (inflammatory tissue growing into the tooth defect), missing teeth, or localized gingivitis around individual teeth.
Diagnosis — Dental Radiographs Find 2.4 Times More
Dental radiographs are the only way to reliably diagnose tooth resorption. Studies show that radiographs detect 2.4 times more affected teeth than clinical examination alone. About 60% of tooth structure lies below the gum line and is invisible. Radiographs also reveal the lesion type (1, 2, or 3), which directly determines treatment. We recommend full-mouth dental radiographs under general anesthesia for all patients — especially older animals. A "missing tooth" during oral examination does not always mean it was lost — the tooth may have resorbed beneath the gum.
Treatment — Type Determines the Method
Type 1 treatment is surgical extraction — both the crown and all roots are completely removed, because the periodontal ligament is intact and the roots may contain inflammatory tissue. Type 2 treatment is crown amputation — since the roots are being replaced by bone, they do not need to be and should not be attempted to be removed (attempting to extract an ankylosed root can lead to jaw fracture). Type 3 is treated the same as Type 1 — complete extraction. Fillings or fluoride treatment are not recommended — in studies, 72% of filled teeth progressed. Tooth resorption never heals on its own. At Eläinklinikka Saari, we perform dental radiographs and surgical tooth extractions — book an appointment for a dental examination.
After Treatment — a Dramatic Change
Owners often report an astonishing change within 24–48 hours after extraction: the pet is more energetic, eats better, is more social, and is "like a different animal." This transformation itself proves how much pain the animal was hiding. There is no known prevention because the cause of the disease remains unknown — the best protection is regular dental examination under general anesthesia so that lesions are detected early.