Parotid Saliva Secretion by Mechanical Stimulation is Site- Specific in the Oral Cavity in Human Subjects

For oral health, it is an important issue to keep and, if deteriorated, to improve salivary secretion. Although mechanical stimulation in chewing and masticating bolus induces the salivary secretion, it is not well-known which sites in oral cavity are effectively stimulated. The present study was designed to investigate the effective sites in the cavity to the mechanical brushing stimulation to induce parotid saliva in human subjects. Parotid saliva was collected using a modified Lashley cup. Saliva secretion was induced by brushing, with normal toothbrush, of the palatal gingival margin of molars, ipsilateral and contralateral to the cup. The occlusal surface of the molars, the gingiva, the palatal rugae, and the tongue were also stimulated by the brushing. Salivary secretion from gingival margins of ipsilateral maxillary and mandibular molars showed comparatively higher rates among them. This indicates that mechanical brushing stimulation of the gingival margin of molars is effective to secrete parotid saliva, possibly activating mechanoreceptors in the mucosa and the periodontal ligament. These may provide beneficial information to improve salivary secretion in oral rehabilitation.