Ngoc Phuong Thanh Chau1, Santosh Pandit2, Jian-Na Cai2, Min-Ho Lee3, Jae-Gyu Jeon4. 1. Department of Preventive Dentistry, School of Dentistry, Institute of Oral Bioscience and BK 21 Plus Program, Chonbuk National University, Jeonju 561-756, Republic of Korea; Department of Odonto-Stomatology, Hue University of Medicine and Pharmacy, Hue University, 06 Ngo Quyen street, Hue City, Viet Nam. 2. Department of Preventive Dentistry, School of Dentistry, Institute of Oral Bioscience and BK 21 Plus Program, Chonbuk National University, Jeonju 561-756, Republic of Korea. 3. Department of Dental Biomaterials, School of Dentistry, Chonbuk National University, Jeonju, Republic of Korea. Electronic address: lmh@jbnu.ac.kr. 4. Department of Preventive Dentistry, School of Dentistry, Institute of Oral Bioscience and BK 21 Plus Program, Chonbuk National University, Jeonju 561-756, Republic of Korea. Electronic address: dentjjk@jbnu.ac.kr.
Abstract
OBJECTIVES: The aim of this study was to evaluate acidogenicity and composition of Streptococcus mutans biofilms on glass ionomer cements (GICs) and then to determine the relationship between the anti-S. mutans biofilm activity and fluoride release rate of the GICs. METHODS: S. mutans biofilms were formed on discs prepared using five commercial GICs. Acid production and fluoride release rates of the biofilms on the GIC discs during biofilm formation (0-94 h) were determined. Next, 94-h-old S. mutans biofilms on GIC discs were analyzed to evaluate the biofilm composition (dry weight, bacterial cell number, and extra-cellular polysaccharide (EPS) amount) using microbiological, biochemical, and confocal laser scanning microscopy (CLSM) methods. Lastly, relationships between the fluoride release rate and changes in acidogenicity and composition of the biofilms were determined using a linear-fitting procedure. RESULTS: All of the tested GICs released fluoride ions. Of the GICs, the two that showed the highest fluoride release rates strongly affected acidogenicity, dry weight, and EPS formation of the biofilms. Furthermore, they reduced the bacterial and EPS bio-volumes and EPS thickness. However, the number of colony forming units (CFUs) of the biofilms was higher than that of the control. Generally, changes in the acidogenicity and composition (except for CFU count) of the biofilms on the GICs followed a negative linear-pattern of fluoride release rate-dependence (R=-0.850 to -0.995, R(2)=0.723-0.990). SIGNIFICANCE: These results suggest that the anti-cariogenic biofilm activity of GICs is closely correlated with their fluoride release rate during biofilm formation.
OBJECTIVES: The aim of this study was to evaluate acidogenicity and composition of Streptococcus mutans biofilms on glass ionomer cements (GICs) and then to determine the relationship between the anti-S. mutans biofilm activity and fluoride release rate of the GICs. METHODS:S. mutans biofilms were formed on discs prepared using five commercial GICs. Acid production and fluoride release rates of the biofilms on the GIC discs during biofilm formation (0-94 h) were determined. Next, 94-h-old S. mutans biofilms on GIC discs were analyzed to evaluate the biofilm composition (dry weight, bacterial cell number, and extra-cellular polysaccharide (EPS) amount) using microbiological, biochemical, and confocal laser scanning microscopy (CLSM) methods. Lastly, relationships between the fluoride release rate and changes in acidogenicity and composition of the biofilms were determined using a linear-fitting procedure. RESULTS: All of the tested GICs released fluoride ions. Of the GICs, the two that showed the highest fluoride release rates strongly affected acidogenicity, dry weight, and EPS formation of the biofilms. Furthermore, they reduced the bacterial and EPS bio-volumes and EPS thickness. However, the number of colony forming units (CFUs) of the biofilms was higher than that of the control. Generally, changes in the acidogenicity and composition (except for CFU count) of the biofilms on the GICs followed a negative linear-pattern of fluoride release rate-dependence (R=-0.850 to -0.995, R(2)=0.723-0.990). SIGNIFICANCE: These results suggest that the anti-cariogenic biofilm activity of GICs is closely correlated with their fluoride release rate during biofilm formation.