ORAL MEDICINE - The influence of pilocarpine and biperiden on pH value and calcium, phosphate, and bicarbonate concentrations in saliva during and after radiotherapy for head and neck cancer. - The authors report the results of a continuing study that compares the effects of a parasympathomimetic agent, pilocarpine, to an anticholinergic agent, biperiden, on the saliva of patients receiving radiotherapy for head and neck malignancies./