To begin, select the participants based on the framed inclusion criteria. For saliva collection, instruct the patient to hold the tube with a funnel and let the saliva flow gradually into the tube along the lower lip for 15 minutes. At the end, ask the participant to spit all the remaining saliva into the tube.
In case of low, unstimulated saliva flow, swab the oral mucosa in infection-suspected areas at least 10 times, and let the patient rinse their mouth with five milliliters of PBS for one minute. Then collect the mouthwash in a 50-milliliter sterile tube and put the swab into it. Add one milliliter of PBS to the collected saliva and vortex the tube for one minute.