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Feline tooth resorption or feline odontoclastic resorptive lesions (RL) (also referred to as cervical line lesions, neck lesions, dental resorptive lesions and feline caries) affect more than one third of adult domestic cats and are the second most common [[:Category:Oral Diseases - Cat|oral problem seen in cats]] (after [[periodontitis]]), with prevalence increasing with age (image 1).

Feline tooth resorption or feline odontoclastic resorptive lesions (RL) (also referred to as cervical line lesions, neck lesions, dental resorptive lesions and feline caries) affect more than one third of adult domestic cats and are the second most common [[:Category:Oral Diseases - Cat|oral problem seen in cats]] (after [[periodontitis]]), with prevalence increasing with age (image 1).

On examination, there is a loss of dental tissue on the [[Enamel Organ#Crown|crown]] or at the neck of the [[:Category:Teeth - Anatomy & Physiology|tooth]]. The crown may be completely resorbed with the remaining root covered with [[Gingiva|gingiva]].

On examination, there is a loss of dental tissue on the [[Tooth - Anatomy & Physiology#Crown|crown]] or at the neck of the [[:Category:Teeth - Anatomy & Physiology|tooth]]. The crown may be completely resorbed with the remaining root covered with [[Gingiva|gingiva]].

==Aetiology and Pathogenesis==

==Aetiology and Pathogenesis==

This classification system works for external root resorption in cats and dogs as well.

This classification system works for external root resorption in cats and dogs as well.

'''SURFACE RESORPTION''' - is initiated subsequent to injury of the [[cementoblast]] layer. It is thought that minor traumas caused by unintentional biting on hard objects, bruxism, etc. can cause localized damage to the [[Enamel Organ#Periodontal Ligament|periodontal ligament]] and trigger this type of resorption. The process is self-limiting and reversible.

'''SURFACE RESORPTION''' - is initiated subsequent to injury of the [[cementoblast]] layer. It is thought that minor traumas caused by unintentional biting on hard objects, bruxism, etc. can cause localized damage to the [[Tooth - Anatomy & Physiology#Periodontal Ligament|periodontal ligament]] and trigger this type of resorption. The process is self-limiting and reversible.

'''REPLACEMENT RESORPTION''' - results in replacement of the dental hard tissue by [[Bones - Anatomy & Physiology|bone]]. When a surface resorption stops, cells from the periodontal ligament will proliferate and populate the resorbed area. Cells from the nearby bone may then arrive first and establish themselves on the resorbed surface. Bone will thus be formed directly upon the dental hard tissue. This results in fusion between bone and tooth, i.e. ankylosis. When the resorptive process is over, the [[osteoblasts]] will form bone in the resorbed area. In this way the dental tissues will gradually be replaced by bone.  

'''REPLACEMENT RESORPTION''' - results in replacement of the dental hard tissue by [[Bones - Anatomy & Physiology|bone]]. When a surface resorption stops, cells from the periodontal ligament will proliferate and populate the resorbed area. Cells from the nearby bone may then arrive first and establish themselves on the resorbed surface. Bone will thus be formed directly upon the dental hard tissue. This results in fusion between bone and tooth, i.e. ankylosis. When the resorptive process is over, the [[osteoblasts]] will form bone in the resorbed area. In this way the dental tissues will gradually be replaced by bone.  

A definitive diagnosis can only be made after an examination and intra-oral radiography with the cat [[Oral Examination Under General Anaesthesia|under general anaesthesia]]. The lesion can be felt as a concavity using a sharp explorer probe (image 6). Lesions are often only detected once the calculus has been removed.

A definitive diagnosis can only be made after an examination and intra-oral radiography with the cat [[Oral Examination Under General Anaesthesia|under general anaesthesia]]. The lesion can be felt as a concavity using a sharp explorer probe (image 6). Lesions are often only detected once the calculus has been removed.

Visualisation is aided by drying the teeth using the air stream from a dental air-water syringe. With normal teeth, the marginal gingiva will lift away from the tooth when the air is directed at the base of the [[Enamel Organ#Crown|crown]], but with RLs, the soft tissue seems “stuck” to the underlying tooth. General anaesthesia is imperative as examination of these lesions in a conscious cat is painful.  

Visualisation is aided by drying the teeth using the air stream from a dental air-water syringe. With normal teeth, the marginal gingiva will lift away from the tooth when the air is directed at the base of the [[Tooth - Anatomy & Physiology#Crown|crown]], but with RLs, the soft tissue seems “stuck” to the underlying tooth. General anaesthesia is imperative as examination of these lesions in a conscious cat is painful.  

Radiography will identify lesions that are localized to the root surfaces within the [[Enamel Organ#Alveolar Bone|alveolar bone]], which cannot be detected by clinical methods. Radiography is also required to confirm the diagnosis and to assess the extent and type of the lesion. Radiographs often reveal a lesion that is more advanced than originally suspected from the clinical examination (image 7).

Radiography will identify lesions that are localized to the root surfaces within the [[Tooth - Anatomy & Physiology#Alveolar Bone|alveolar bone]], which cannot be detected by clinical methods. Radiography is also required to confirm the diagnosis and to assess the extent and type of the lesion. Radiographs often reveal a lesion that is more advanced than originally suspected from the clinical examination (image 7).

[[Radiographic Interpretation of Tooth Resorption - Small Animal|Radiographic Features of RLs]]: <br>

[[Radiographic Interpretation of Tooth Resorption - Small Animal|Radiographic Features of RLs]]: <br>