Radiation Caries and its management

Radiation caries results from xerostomia, which permits cariogenic bacteria to proliferate unopposed by the usual lysosomes and IgA immunoglobulins in saliva and causes the loss of the saliva’s natural buffering capacity.

Caries in nonirradiated individuals occurs in pits, in fissures, and interproximally. It is also chalky and soft from dissolved tooth structure. 

Radiation caries, by contrast, is hard and black. It occurs at the gingival margin, cusp tips, incisal surfaces, or throughout the tooth.

Radiationcaries is either present only in the irradiated field or is more severe in the irradiated field.

Radiation caries is mainly due to pulpal necrosis and odontoblast death, which causes deterioration of both the dentin and the dentinoenamel junction. The enamel is subsequently lost from the dentin because of dentinal dehydration and dentinoenamel junction deterioration.The exposed dentin becomes black or brown and hard and deteriorates further.

 Pulp testing teeth with radiation caries may or may not produce a response.

Vitality of any tissue is a matter not of nerve enervation but of blood supply and perfusion. Because nerves are the most radiation-resistant tissues and because pulpal nerve endings arise from cells in the gasserian ganglion, the tooth with radiation caries may have a responsive pulp but is actually nonvital due to avascular necrosis of the vascular pulpal tissues, including the odontoblasts.

The teeth most at risk of developing radiation caries are those in the direct path of 6,000-cGy or greater radiation .

Even the best oral hygiene, dental care, and fluoride carriers will not prevent all radiation caries.

Once developed, radiation caries should be treated promptly using restorative techniques appropriate for the degree of lost and involved tooth substance.