Sparing of Contralateral Major Salivary Glands Has a Significant Effect on Oral Health in Patients Treated with Radical Radiotherapy of Head and Neck Tumors

Has a conscious exclusion of the contralateral major salivary glands (parotid, submandibular, and sublingual glands) a significant impact on the milieu of the oral cavity (saliva flow, pH, buffer capacity, and colonisation with Streptococcus mutans) in patients with ENT tumors receiving radical radiotherapy? Patients and Methods: 20 consecutive consentient patients with ENT tumors were evaluated once before, weekly during, and 6 weeks after the end of treatment in regard to saliva flow, ph, buffer capacity, and colonisation with Streptococcus mutans. In 13 patients the major salivary glands on both sides were included in the treated volume, in seven patients the treatment portals excluded consciously the contralateral major salivary glands. Results: The stimulated saliva flow decreases already during the 1st week of radiotherapy, the decrease follows the dose exponentially; the saliva flow is further reduced in the weeks after the end of treatment. The effect is less pronounced in patients with sparing of contralateral major salivary glands. The majority of patients with unilateral sparing of the major salivary glands retain the baseline value of buffer capacity, whereas buffer capacity of all patients with inclusion of all major salivary glands is markedly reduced with 20 Gy already, without signs of recovery when treatment has stopped. With unilateral salivary gland sparing the pH always remains basic, in bilaterally irradiated patients the pH changes from a mean of 7.3 to 5.8 during treatment. The colonisation with Streptococcus mutans varies little in both groups during the radiotherapy; after the end of therapy, it is higher in bilaterally irradiated patients. Conclusions: The conscious arrangement of irradiation portals in order to spare contralateral major salivary glands in patients with radical radiotherapy of ENT tumors has a significant influence on the oral environment: the stimulated saliva flow is higher, the buffer capacity retains the baseline value, the saliva pH remains basic, and the colonisation with Streptococcus mutans is reduced.