Influence of the location of the parotid duct orifice on oral clearance

• Published in: Archives of oral biology 2009-03, Vol.54 (3), p.274-278
• Main Authors: Suzuki, Akira, Watanabe, Shigeru, Ono, Yoshiaki, Ohashi, Hideo, Pai, Chenghua, Xing, Xianghui, Wang, Xiaojing
• Format: Article
• Language: English
• Subjects: Adult; Advanced Basic Science; Analysis of Variance; Dental Caries - metabolism; Dental Caries Susceptibility; Dentistry; Female; Humans; Male; Maxilla - anatomy & histology; Maxillary molars; Molar - anatomy & histology; Mouth - metabolism; Oral clearance; Parotid duct orifice; Parotid Gland - anatomy & histology; Parotid saliva flow rate; Saliva - secretion; Salivary Ducts - anatomy & histology; Secretory Rate - physiology; Young Adult
• ISSN: 0003-9969; 1879-1506
• DOI: 10.1016/j.archoralbio.2008.11.008

Summary Objectives To determine the location of the parotid duct orifice in relation to the maxillary molars and its influence on oral clearance on the buccal surfaces of the maxillary molars. Methods A 2-mm hole was made at the centre of an adhesive therapeutic agent for aphthous stomatitis and the agent was placed on the mucosa so that the hole matched the parotid duct orifice. To locate the orifice, an impression of the buccal tooth surfaces and mucosa around the agent was taken with the teeth in centric occlusion. To evaluate the oral clearance rate, 12 subjects who displayed the parotid duct orifice within 1S.D. of the mean values obtained from the original 35 subjects were selected. 1% agar containing 1 mol/l potassium chloride was placed into three cylinders positioned horizontally, 6 mm apart, in an acrylic holder centred over the mean duct location. The diffusion chambers were taken from the mouth at selected time intervals and the gel transferred quantitatively to flasks containing 300 ml of 100 ppm NaCl, which was assayed for potassium by atomic absorption spectrophotometry. Half-times for clearance were calculated. Results The mean location of the parotid duct orifice was −0.4 mm (range −7.5 to +6.1 mm) mesial to the contact surface between the maxillary first and second molars (where negative values indicate mesial and positive values distal) and 7.2 mm (range +3.8 to +10.4 mm) above a line touching the buccal cusps of the upper molars. The clearance half-time values were shortest for the central cylinder whether salivary flow was unstimulated or stimulated and when flow was unstimulated the clearance half-time was shorter for the mesial than the distal cylinder. Conclusion The degree of individual variation in the location of the parotid duct orifice is great and its exact location will markedly affect oral clearance at different positions on the buccal surfaces of the upper molars.