The effect of sucrose on plaque and saliva urease levels in vivo
Accepted 28 December 2009.
Abstract
Objective
Dietary sugar exposures induce an immediate drop of the plaque pH. Based on in vitro observations, it was hypothesized that oral bacteria may rapidly respond to this environmental change by increasing the activity or expression of alkali-generating pathways, such as the urease pathway. The objective of this exploratory in vivo study was to determine the short-term effect of a brief sucrose exposure on plaque and saliva urease activity and expression, and to relate this effect to caries experience.
Methods
Urease activity levels were measured in plaque and saliva samples collected from 20 children during fasting conditions and 30min after rinsing with a sucrose solution. Streptococcus salivarius ureC-specific mRNA in saliva was quantified using real-time RT-PCR. The impact of host-related factors, such as age, gender, sugar consumption, salivary mutans streptococci levels and caries status on urease activity was evaluated.
Results
Plaque urease activity under fasting conditions was higher in subjects with low caries and mutans streptococci levels. This difference was not observed after the sucrose exposure. The response of urease to sucrose in vivo did not depend on caries experience or salivary mutans levels. Significant increase in urease activity of plaque and saliva after exposure to sucrose was observed only in the subjects who had low urease levels at baseline.
Conclusions
The findings of this exploratory study suggest that plaque urease activity may have an important long-term influence in caries development but not during a cariogenic challenge.
aUniversity of Puerto Rico, School of Dental Medicine, San Juan, Puerto Rico
bUniversity of Puerto Rico, School of Public Health, San Juan, Puerto Rico
cDepartment of Operative Dentistry, College of Dentistry, University of Florida, Gainesville, FL, United States
dDepartment of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, United States
Corresponding author at: Department of Oral Biology, School of Dental Medicine, University of Puerto Rico Medical Sciences Campus, PO Box 365067, San Juan 00936-5067, Puerto Rico. Tel.: +787 758 2525x2523; fax: +787 763 4868.
ABSTRACT