Salivary flow rate and pH after radiotherapy of the head and neck region

Abstract

The most common sequelae in head and neck cancer patients submitted to radiotherapy (60Cobalt) is postirradiation hyposalivation. This leads to a change in oral physiology, and, as a consequence, the irradiated individual is suceptible to infections and caries lesions. The aim of this study was to evaluate the behaviour of stimulated whole saliva flow rate (SWSFR) during and after radiotherapy treatment for head and neck cancer by lateral opposed fields. Six samples of mechanically stimulated whole saliva were collected of each individual and evaluated by gravimetric method. The first sample was collected before radiotherapy; the second one after 1500cGy dose; the third one after the last dose of treatment and the remainder samples in intervals of subsequent two months up to six months after the end of treatment. The SWSFR decreased in 50% after a dose of 1500cGy (1/4 of received treatment). After radiation therapy, the SWSFR was 0,33ml/min and after six months was 0,20ml/min. These values represented, respectively, a decreasing in 64% and 78% of initial values (ANOVA, Tukey's Test p<0.05). Based in these results, the authors concluded radiotherapy when applied in malign neoplasms of the head and neck region by lateral opposed fields was able to decrease significantly salivary flow rate. Intensive preventive dental care during and after radiotherapy seems to be an useful tool to avoid radiation caries and their complications.