Radiation Caries

Radiation caries occurs regardless of the previous caries history.  It is a rapid form of decay with frank lesions seen in 3 months vs. the 18 months associated with caries development the non-irradiated patient.
After radiation therapy, saliva no longer acts as a buffering and lubricating agent.  This loss of protection usually provided by saliva increases susceptibility to caries.
The decay pattern in radiation caries is different from non-irradiated teeth.  Incisal edges, cusp tips and cervical areas are the involved surfaces.  The lesion begins as diffuse demineralization that encircles the tooth and causes it to break off at the gingival margin.  Black lesions are also common.
The change in bacterial flora, the decrease in pH, the change in diet, and the painful inflamed oral mucosa leading to poor oral hygiene, all add up to an increased risk of decay.
Here seen as darkened lesions in the gingival 1/3 of the exposed clinical crown
ORAL00000016.gif Xerostomia Secondary to Radiation Therapy
ORAL00000016.gif Common Oral Lesions