Sialometry Whole salivary flow rates, unstimulated and stimulated, will be measured from the floor of the mouth and labial vestibule preoperatively and at 2-3 weeks after surgery before start of radiation treatment. After radiation treatment, flow evaluation will be done at 6 months and 12 months. Each time, the flow rate will be measured at rest and after stimulation. Stimulated flow rates will be measured by dropping 0.2 ml of 6% citric acid solution on the dorsal surface of the tongue every 30 seconds (Dawes 1975).Salivary samples will be collected by means of a an appliance (Pederson et al 1985) consisting of a Drummond micropipette holder (for use with 20 microlitre micropipettes) fitted with a 2 ml latex dropper bulb. A 2.5 cm length of 50 microlitre micropipette is inserted into the holder until its outer end no longer protrudes. During collection, the patient tips the head slight forward to produce pooling of saliva at the anterior floor of mouth and mandibular labial vestibule. The micropipette extruding from the end of the collection device is used to aspirate the pooled salivary secretions from these two sites. As saliva flows up the micropipette, it spills into the glass sleeve of the collection device between the top of the silicon end-piece and the top of the micropipette.