Changes

===Types===

===Types===

Radiographs of teeth affected with TRs show distinct changes. The [[Enamel Organ#Root|roots]] of some affected teeth seem to “disappear” as they lose radiodense root tissue at a similar rate to the simultaneously occurring osseous repair, effectively making the roots appear to blend with the surrounding bone. The [[Tooth - Anatomy & Physiology|Periodontal Ligament|periodontal ligament]] and structural details are lost. Other TRs retain areas of normal radiodensity interspersed with radiolucencies caused by resorption and do not lose the detail of the periodontal ligament space and root structures in those areas not directly undergoing resorption. Areas of root resorption are often patchy, remaining radiolucent because the lost root substance is not replaced by reparative tissue. This type of TR also commonly demonstrates concurrent [[Periodontal Disease|periodontal]] or [[Endodontic Conditions|endodontic disease]].

Radiographs of teeth affected with TRs show distinct changes. The [[Tooth - Anatomy & Physiology#Root|roots]] of some affected teeth seem to “disappear” as they lose radiodense root tissue at a similar rate to the simultaneously occurring osseous repair, effectively making the roots appear to blend with the surrounding bone. The [[Tooth - Anatomy & Physiology|Periodontal Ligament|periodontal ligament]] and structural details are lost. Other TRs retain areas of normal radiodensity interspersed with radiolucencies caused by resorption and do not lose the detail of the periodontal ligament space and root structures in those areas not directly undergoing resorption. Areas of root resorption are often patchy, remaining radiolucent because the lost root substance is not replaced by reparative tissue. This type of TR also commonly demonstrates concurrent [[Periodontal Disease|periodontal]] or [[Endodontic Conditions|endodontic disease]].

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Lesions in which the roots are not replaced by bone-dense tissue are termed type 1 lesions while those in which the roots are replaced and appear to disappear are type 2 lesions. Both types of lesion can be found in the same individual cat, and even in the same tooth with one root appearing to be type 1 and the other root appearing to be a type 2. It is unknown if this is a stage of severity in which the root or region with the appearance of a type 1 lesion might eventually progress to become a type 2 lesion.<br><br>

Lesions in which the roots are not replaced by bone-dense tissue are termed type 1 lesions while those in which the roots are replaced and appear to disappear are type 2 lesions. Both types of lesion can be found in the same individual cat, and even in the same tooth with one root appearing to be type 1 and the other root appearing to be a type 2. It is unknown if this is a stage of severity in which the root or region with the appearance of a type 1 lesion might eventually progress to become a type 2 lesion.<br><br>

There are a number of staging systems in the literature for recording the severity or extent of lesions. Of these, the most logical and clear one categorizes TRs by severity according to objective and easily determined observation that places them into stages that may have clinical relevance.

There are a number of staging systems in the literature for recording the severity or extent of lesions. Of these, the most logical and clear one categorizes TRs by severity according to objective and easily determined observation that places them into stages that may have clinical relevance.

   

   

*'''Stage 1''' - A lesion that affects only the [[Enamel Organ#Cementum|cementum]] and/or marginal [[Enamel Organ#Enamel|enamel]] but does not involve the [[Enamel Organ#dentine|dentine]]. This stage occurs subgingivally where the tooth surface is exposed to cells that can become [[Enamel Organ#Odontoclasts|odontoclasts]]. It is uncommon to identify TRs at this stage. Stage 1 lesions are not radiographically apparent.

*'''Stage 1''' - A lesion that affects only the [[Tooth - Anatomy & Physiology#Cementum|cementum]] and/or marginal [[Tooth - Anatomy & Physiology#Enamel|enamel]] but does not involve the [[Tooth - Anatomy & Physiology#dentine|dentine]]. This stage occurs subgingivally where the tooth surface is exposed to cells that can become [[Tooth - Anatomy & Physiology#Odontoclasts|odontoclasts]]. It is uncommon to identify TRs at this stage. Stage 1 lesions are not radiographically apparent.

*'''Stage 2''' - A lesion that involves the dentine but not the [[Enamel Organ#Pulp|pulp]].  

*'''Stage 2''' - A lesion that involves the dentine but not the [[Tooth - Anatomy & Physiology#Pulp|pulp]].  

*'''Stage 3''' - A lesion that involves the pulp. Radiographs may be necessary to evaluate pulp involvement.

*'''Stage 3''' - A lesion that involves the pulp. Radiographs may be necessary to evaluate pulp involvement.

*'''Stage 4''' - A lesion that has destroyed a significant amount of the [[Enamel Organ#Crown|crown]], weakening the crown and placing it at risk of fracture even with only moderate trauma.

*'''Stage 4''' - A lesion that has destroyed a significant amount of the [[Tooth - Anatomy & Physiology#Crown|crown]], weakening the crown and placing it at risk of fracture even with only moderate trauma.

*'''Stage 5''' - A lesion that has destroyed the entire crown of the tooth. The [[gingiva]] has grown over the roots and no tooth material is exposed to the [[:Category:Oral Cavity - Anatomy & Physiology|oral cavity]].

*'''Stage 5''' - A lesion that has destroyed the entire crown of the tooth. The [[gingiva]] has grown over the roots and no tooth material is exposed to the [[:Category:Oral Cavity - Anatomy & Physiology|oral cavity]].

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