title: Evaluation of pH at the bacteria-dental cement interface.
abstract: Physiochemical assessment of the parasite-biomaterial interface is essential in the development of new biomaterials. The purpose of this study was to develop a method to evaluate pH at the bacteria-dental cement interface and to demonstrate physiochemical interaction at the interface. The experimental apparatus with a well (4.0 mm in diameter and 2.0 mm deep) was made of polymethyl methacrylate with dental cement or polymethyl methacrylate (control) at the bottom. Three representative dental cements (glass-ionomer, zinc phosphate, and zinc oxide-eugenol cements) were used. Each specimen was immersed in 2 mM potassium phosphate buffer for 10 min, 24 hrs, 1 wk, or 4 wks. The well was packed with Streptococcus mutans NCTC 10449, and a miniature pH electrode was placed at the interface between bacterial cells and dental cement. The pH was monitored after the addition of 1% glucose, and the fluoride contained in the cells was quantified. Glass-ionomer cement inhibited the bacteria-induced pH fall significantly compared with polymethyl methacrylate (control) at the interface (10 min, 5.16 ± 0.19 vs. 4.50 ± 0.07; 24 hrs, 5.20 ± 0.07 vs. 4.59 ± 0.11; 1 wk, 5.34 ± 0.14 vs. 4.57 ± 0.11; and 4 wks, 4.95 ± 0.27 vs. 4.40 ± 0.14), probably due to the fluoride released from the cement. This method could be useful for the assessment of pH at the parasite-biomaterial interface.
authors.affiliation: Division of Oral Ecology and Biochemistry, Department of Oral Biology, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Mayanagi
authors.forename: K
authors.initials: K
authors.lastname: Igarashi
authors.forename: J
authors.initials: J
authors.lastname: Washio
authors.forename: K
authors.initials: K
authors.lastname: Nakajo
authors.forename: H
authors.initials: H
authors.lastname: Domon-Tawaraya
authors.forename: N
authors.initials: N
authors.lastname: Takahashi
mesh_terms: D003763:Dental Leakage / Q000517:prevention & control*; D003793:Dental Restoration, Permanent / Q000379:methods*; D004566:Electrodes; D005459:Fluorides / Q000032:analysis; D005899:Glass Ionomer Cements; D006863:Hydrogen-Ion Concentration; D013295:Streptococcus mutans / Q000378:metabolism*; D015035:Zinc Oxide-Eugenol Cement; D015036:Zinc Phosphate Cement
chemical_list: D005899:Glass Ionomer Cements; D015035:Zinc Oxide-Eugenol Cement; D015036:Zinc Phosphate Cement; D005459:Fluorides