Department of Oral Biology

C. Dawes
B.Sc., B.D.S. (Manc), Ph.D. (Durh).
Professor Emeritu

dawesc@ms.umanitoba.ca


Saliva and Oral Health

My primary research interest is in the role of saliva in oral and general health. We have studied many of the physiological factors which affect salivary flow rate and composition, the role of saliva in oral clearance, particularly of sugars and of bacteria, the influence of salivary flow rate and composition on the metabolism and pH of dental plaque, the relation between the volume of saliva in the mouth and the sensation of oral dryness, the effect of gum chewing on salivary flow rate and composition, and factors influencing the composition of plaque fluid, the fluid phase of dental plaque.

We showed that saliva is present in the mouth as a thin film, less than 0.1 mm in thickness, which moves at different velocities in different regions of the mouth (0.8 - 8 mm/min when salivary flow is unstimulated). The more slowly the film of saliva moves over dental plaque, the less readily can bacterial metabolites, such as acid, be cleared from the plaque. We have also shown great site-specificity in the rate of clearance of sugar from the mouth. These findings help to explain the site-specificity of both smooth-surface dental caries and supragingival calculus deposition.

Relevant publications

• Dawes C, Tsang RWL, Suelzle T (2001). The effects of gum chewing, four oral hygiene procedures and two saliva collection techniques, on the output of bacteria into human whole saliva. Arch Oral Biol 46:625-632.
  
• Dawes C (2003). Estimates, from salivary analyses, of the turnover time of the oral mucosal epithelium in humans and the number of bacteria in an edentulous mouth. Arch Oral Biol 48:329-336.
  
• Dawes C (2003). What is the critical pH and why does a tooth dissolve in acid? J Can Dent Assoc 69:722-724.
  
• Dawes C, Odlum O (2004). Salivary status in a treated head and neck cancer patient group. J Can Dent Assoc 70:397-400.
  
• Dawes C (2004) How much saliva is enough for avoidance of xerostomia? Caries Res 38:236-240.
  
• Dawes C (2004). Factors influencing salivary flow rate and composition. In: Saliva and Oral Health. M. Edgar, C. Dawes, and D. O'Mullane, Eds., 3rd edition. British Dental Assoc., London. Chap. 3, pp. 32-49.
  
• Dawes C (2004). Clearance of substances from the oral cavity - implication for oral health. In: Saliva and Oral Health. M. Edgar, C. Dawes, and D. O'Mullane, Eds., 3rd edition. British Dental Assoc., London. Chap. 5, pp. 71-85.
  
• Dawes C, Kubieniec K (2004). The effects of prolonged gum chewing on salivary flow rate and composition. Arch Oral Biol 49:665-669.
  
• Itthagarun A, King NM, Yiu CKY, Dawes C (2005). The effects of chewing gums containing calcium phosphate on the remineralization of artificial caries-like lesions in situ. Caries Res 39:251-254.
  
• Dawes C (2005). The unstimulated salivary flow rate after prolonged gum chewing. Arch Oral Biol 50:561-563.
  
• Kariyawasam AP, Dawes C (2005). A circannual rhythm in unstimulated salivary flow rate when the ambient temperature varies by only about 2°C. Arch Oral Biol 50:919-922.
  
• Dawes C (2006). Absorption of urea through the oral mucosa and estimation of the percentage of secreted whole saliva inadvertently swallowed during saliva collection. Arch Oral Biol 51:111-116.
  
• Dawes C (2006). Why does supragingival calculus form preferentially on the lingual surfaces of the six lower anterior teeth? J Can Dent Assoc 72:923-926.
  
• Dawes C, Boroditsky CL (2008). Rapid and severe tooth erosion from swimming in an improperly-chlorinated pool: Case report. J Can Dent Assoc 74:359-361.
  
• Dawes C (2008). Salivary flow patterns and the health of hard and soft oral tissues. JADA 139:18S-24S.