Feline Odontoclastic Resorptive Lesions

Also known as: FORL — Neck lesions

Introduction

Feline odontoclastic resorptive lesions (FORLs) are the most commonly seen dental lesions in cats. On examination, there is a loss of dental tissue on the crown or at the neck of the teeth. The crown may be completely resorbed with the remaining root covered with gingiva.

The aetiology and pathogenesis of FORLs has not yet been demonstrated but is almost certainly multifactorial. Possible hypotheses that have been suggested include, the texture of the diet, abnormal calcium regulation, hypervitaminosis A, mechanical stress, anatomical abnormalities of the teeth, viral infections and plaque bacteria and periodontal disease.

They affect 20% of cats.

Typical Signalment

There are no sex or breed predispositions, however, it does become more prevalent with increasing age.

Diagnosis

Clinical Signs

Anorexia, drooling, lethargy and pain on contact with the lesions.

Oral Examination

Visual Examination will identify the lesions or inflammed gingiva that overlies the remaining root.

Lesions that are subgingival may be identified using a dental probe.

Diagnostic Imaging

Radiographic signs of FORLs include erosion of alveolar bone at the cementoenamel junction, root resorption, root ankylosis and subsequent periodontal space loss and resorption of the dental crown.

Classifying the Lesions

Classifying the lesions allows a logical treatment regime to be implemented. It can be based on the severity of the resorptive lesions.

Disease type	Area affected
Stage 1	Enamel only
Stage 2	Enamel and dentine
Stage 3	Pulp exposure
Stage 4	Extensive structural damage
Stage 5a	Crown is resorbed but the roots are retained.
Stage 5b	Crown is intact but the root is resorbed

Pathology

Odontoclasts attack external and internal to the tooth. Initially they start at the neck/cervical region and extend into tooth root they also enter the root via the apical foramen (stage 3 lesions). Odontoclasts are normally only active in young animals to resorb the deciduous teeth to make way for the permanent teeth so this is abnormal activation in adults.

FORLs are different from dental caries which is demineralization by bacteria fermenting carbohydrate on the enamel.

Additionally there may also be inflammatory infiltrates into the resportive lesions.

Treatment

There are various treatment options available for the different stages of disease.

Stage 1-2 These require a scale and polish, fluoride treatment and the use of pit and fissure sealant.

Stage 2 Firstly a Scale and polish followed by restoration of the tooth using glass ionomer, compomer or composite (high failure rate.)

Stage 2-4 Extractions are necessary and also crown amputation whilst retaining the root.

Stage 5a Extractions again whilst retaining the root.

Stage 5b Lesions require crown amputation.

Feline Odontoclastic Resorptive Lesions Learning Resources
Literature Search Search for recent publications via CAB Abstract (CABI log in required)	Feline odontoclastic resorptive lesions publications

References

Tutt, C., Deeprose, J. and Crossley, D. (2007) BSAVA Manual of Canine and Feline Dentistry (3rd Edition) BSAVA

Merck & Co (2008) The Merck Veterinary Manual Merial

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