Dental plaque pH and micro-organisms during hyposalivation

Area of Science:

• Oral health research
• Microbiology
• Dental science

Background:

• Previous studies indicated differences in saliva flow and protein levels in primary Sjögren's syndrome and head and neck radiation therapy patients.
• The current study investigates potential differences in dental plaque pH, acidogenic microorganisms, and saliva buffering capacity.

Purpose of the Study:

• To test the hypothesis that plaque pH, acidogenic microorganisms, and saliva buffering capacity differ in individuals with primary Sjögren's syndrome or after head and neck radiation therapy.
• To identify factors influencing dental plaque pH in these patient groups.

Main Methods:

• Plaque pH was measured using the microtouch method after a sucrose rinse.
• Plaque samples were analyzed for total and acidogenic microorganism counts (lactobacilli, Candida, mutans streptococci).
• Saliva buffering capacity was assessed.

Main Results:

• The head and neck radiation therapy group showed significantly lower plaque pH compared to controls.
• Increased numbers of lactobacilli and Candida species were observed in the irradiated group.
• Reduced saliva buffering capacity was found in the irradiated group, but not in the Sjögren's syndrome group.
• Buccal minor salivary gland secretion rate and mutans streptococci counts were significant predictors of plaque pH.

Conclusions:

• Head and neck radiation therapy significantly impacts dental plaque pH, microbial composition, and salivary buffering capacity.
• Primary Sjögren's syndrome did not show the same significant alterations in plaque pH and buffering capacity in this study.
• Salivary gland function and specific bacterial counts are important determinants of dental plaque pH in these patient populations.