Evaluation of pH at the bacteria-dental cement interface

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. © 2011 international & american associations for dental research.