Resorptive Lesions in Dogs and Cats

introduction.
Pathological tooth resorption occurs in many species and is most common in domestic cats. it has many names including resorptive lesions, feline odontoclastic resorptive lesions (forL) and necklesions. the currently recommended term is tooth resorption (tr). the aetiology of tr is not well understood. possible proposed theories are abnormal forces applied to the teeth, inflammation, excessive vitamin D and an acid pH of food. tr has been reported to cause discomfort. tr affecting the root will not be painfull but when tr is exposed to the oral cavity tooth sensitivity will defenitly occur.

Feline tooth resorption.
It appears that up to around 30% of cats presented for any reason to veterinary hospi- tals will have one or more tr (2). in dental patients a higher prevalence is found. the dis- ease occurs from about two years of age onwards and its prevalence increases with increasing age. the lesion affecting cats is typically an external resorption, it begins on the outside of the tooth roots on the cementum.
When the lesion affects the tooth crown granulation tissue will cover the defect. Crown defects due to tr may be detected with a dental explorer.
Without dental radiographic examination, many lesions are missed and the extent of lesions are underestimated. there are two radiographically distinct types of tr in cats. the roots of type 1 lesions maintain normal general radio-opacity and a distinct peri- dontal ligament space. the roots of a type 2 lesion have generalised loss of radio-opac- ity and there is no clear periodontal ligament space.
type 1 lesions are commonly associated with inflammation such as periodontitis and endodontic disease.
a five stages grading system has been developed for tr in cats.

Stage 1: very early resorption only into the cementum of the root, no dentine involved
Stage 2: resorption extends into dentine, not into the pulp
Stage 3: resorption involves the pulp
Stage 4: crown destruction
Stage 5: no remaining supragingival crown, the gingiva covers the site.

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