Dental Dysplasia

Preclinical studies assess the safety and potential toxicity of each new drugs. therefore it is crucial to understand each pathological change even in uncommon tissues such as teeth.

Incisors grow throughout life in rodents. This characteristic coupled with infection, chronic inflammation, nutritional/metabolic/vascular alterations, and injury/fracture can result in abnormal development of odontogenic tissues. A version of dental dysplasia and degeneration is associated with exposure to angiogenesis-inhibitor drugs and this in only one example of the type of dysplastic lesion than can result from angiogenic inhibition.

Dysplastic lesions can vary considerable depending on the nature and extent of injury, the tissues affected and the plane of section. Alveolar bone, cementum, dentin, enamel and/or connective tissue resembling that of the dental papilla may develop in various combinations and abnormal patterns. In some cases, the tooth socket becomes filled with large irregular masses of osteodentin surrounded by fragments of the original tooth. Tooth-like structures (denticles) with tissue resembling the dental papilla may also form but tend to remain relatively small and solitary. Dental dysplasia  needs to be carefully considered as an alternative diagnosis to a dental neoplasm (odontoma). Dental dysplasia (abnormal development) may give rise to fractures which are sometimes difficult to see microscopically due to histological processing/sectioning in areas of the tooth not containing the fracture. Dysplasia and fractures may also lead to ankylosis, which is fusion of alveolar bone with tooth.

From: Toxicological Pathology, Non Clinical Safety assessment Sahota, Popp, Hardisty, Gopinath & Bouhard