The formation of cariogenic plaque to contemporary adhesive restorative materials: an in vitro study

Abstract

The research exploiting the ability of dental materials to induce or prevent secondary caries (SC) development still seems inconclusive. Controlling bacterial adhesion by releasing bacteriostatic ions and improving the surface structure has been suggested to reduce the occurrence of SC. This paper analyses the impact of five distinctively composed dental materials on cariogenic biofilm formation. Forty-five specimens of three composites (CeramX Spectra ST, Admira Fusion, Beautifil II) and two glass-ionomers (Fuji II LC, Caredyne Restore), respectively, were incubated in bacterial suspension composed of Streptococcus mutans, Lactobacillus acidophilus, Streptococcus mitis, Streptococcus sanguinis, and Streptococcus salivarius at pH 7.0 and 5.5. Coverslips were used as a control. Adhered bacteria were collected after 2, 4, 6, 12, 24, and 48 h and analyzed using quantitative polymerase chain reaction (qPCR). Fluoride leakage was measured at each collection. The specimens' surface topography was assessed using interferometry. In the present study, surface roughness seemed to have a partial role in bacterial adhesion and biofilm formation, together with chemical composition of the materials tested. Despite differences in fluoride leakage, biofilm accumulation was similar across materials, but the number of adhered bacteria differed significantly. A release of other ions may also affect adhesion. These variations suggest that certain materials may be more prone to initiating secondary caries.

Keywords: Biofilm; Caries prevention; Dental materials; Fluoride; Ions.

Fig. 1

The flowchart illustrating material distribution and data collection in the study

Fig. 2

Comparison of bacteria growth (AUC_0–48 h) in different pH conditions for all materials tested. Asterix marks difference in growth between different pH conditions (p < 0.05)

Fig. 3

Bacterial concentration (log copy/10mm², MV, n = 6), obtained at 0–48 h on Ceram.x (CE), Beautifil II (BE), Admira Fusion (AD), Fuji II LC (FU), Caredyne Restore (CA), and control (Ctr) in two pH conditions

Fig. 4

Fluoride leakage from discs during the microbiological experiment. Results presented in ppm (1 disc in 1 mL)

Fig. 5

Significant differences in surface topography observed (Sdr) within the same material after 48 h in different environments. * = p < 0.05, ** = p < 0.01, *** = p < 0.001, **** = p < 0.0001