IADR Abstract Archives
Use of Streptococcus mutans for Testing Ion-Releasing Cariostatic Dental Materials
Objectives: Secondary caries is a frequent reason for restoration replacement. Some types of filling materials inhibit secondary caries. Here, Streptococcus mutans fed with sucrose was used to test caries inhibition of a fluoride releasing glass ionomer cement and a new restorative material releasing hydroxide, calcium and fluoride ions. A conventional composite served as control.
Methods: Three bovine teeth per group were embedded in a resin and sanded down to expose the enamel. 5 mm wide rectangular cavities were prepared on either side (left/right) of the samples leaving exactly 5 mm enamel in-between. Left cavities were filled with Fuji IX (GC) or Cention N (Ivoclar Vivadent). Right cavities were filled with Tetric N-Ceram as control (Ivoclar Vivadent). One third of each sample was isolated with tape to retain a reference area of non-demineralized enamel. Specimens were exposed to a simulated caries attack utilizing S. mutans growing on Brain Heart Infusion (BHI) supplemented with sucrose (1 wt%). Specimens were incubated for 48 h at 37°C. After 16, 24, and 40 h the growth medium was replaced to ensure continued nutrient supply. Demineralization of enamel at the margins was detected with instrumented microhardness testing and fluorescence microscopy.
Results: Hardness of healthy enamel was 373±53 HVIT (Vickers hardness measured by instrumented testing). After the caries attack, enamel hardness at the margin of the conventional composite was reduced to 170±33 HVIT. At Fuji IX and Cention N margins hardness was only reduced to 225±65 and 267±72 HVIT, respectively. Fluorescence imaging showed less enamel demineralization at Fuji IX and Cention N margins compared to Tetric N-Ceram margins.
Conclusions: Both, the fluoride releasing Fuji IX and the calcium-, fluoride- and hydroxide ion releasing Cention N were able to reduce demineralization at enamel margins compared to the inert composite filling material.
Methods: Three bovine teeth per group were embedded in a resin and sanded down to expose the enamel. 5 mm wide rectangular cavities were prepared on either side (left/right) of the samples leaving exactly 5 mm enamel in-between. Left cavities were filled with Fuji IX (GC) or Cention N (Ivoclar Vivadent). Right cavities were filled with Tetric N-Ceram as control (Ivoclar Vivadent). One third of each sample was isolated with tape to retain a reference area of non-demineralized enamel. Specimens were exposed to a simulated caries attack utilizing S. mutans growing on Brain Heart Infusion (BHI) supplemented with sucrose (1 wt%). Specimens were incubated for 48 h at 37°C. After 16, 24, and 40 h the growth medium was replaced to ensure continued nutrient supply. Demineralization of enamel at the margins was detected with instrumented microhardness testing and fluorescence microscopy.
Results: Hardness of healthy enamel was 373±53 HVIT (Vickers hardness measured by instrumented testing). After the caries attack, enamel hardness at the margin of the conventional composite was reduced to 170±33 HVIT. At Fuji IX and Cention N margins hardness was only reduced to 225±65 and 267±72 HVIT, respectively. Fluorescence imaging showed less enamel demineralization at Fuji IX and Cention N margins compared to Tetric N-Ceram margins.
Conclusions: Both, the fluoride releasing Fuji IX and the calcium-, fluoride- and hydroxide ion releasing Cention N were able to reduce demineralization at enamel margins compared to the inert composite filling material.