IADR Abstract Archives
The Effect of Biofilms on the Surface of Resin-Composites
Objectives: Cariogenic bacteria can degrade the surface of composites and thus increase their roughness. Increased roughness and subsequent improved bacterial adhesion may facilitate the development of secondary caries around composites. However, the extent of bacteria-induced surface changes and its relationship to the material composition are still not clear.
Therefore, the objective of this study was to investigate the effect of mono- and multispecies biofilms on surface roughness and topography of two dental composites with different composition regarding resin matrix and fillers.
Methods: Disk-shaped specimens of a paste-like, Bis-GMA free (Gradia Direct Anterior, GC), and flowable, Bis-GMA-based composite (Tetric EvoFlow, Ivoclar Vivadent) were prepared using polytetrafluoroethylene molds and glass slides. After ethylene-oxide sterilization (38°C), specimens (n=3) were incubated with 1) Streptococcus mutans, 2) mixed bacterial culture (Streptococcus mutans, Streptococcus sanguinis, Anctinomyces naeslundii and Fusobacterium nucleatum) or 3) sterile bacterial growth medium (control). Following 6-week incubation, the attached biofilms were collected for qPCR assessment, after which the specimens were cleaned and analyzed with atomic force microscope (AFM) at lower (10x10µm) and higher resolution (1x1µm) with regard to surface roughness (Rq) and topography. Additional samples with attached biofilms were observed with scanning electron microscope (SEM).
Results: qPCR analysis revealed a similar amount of bacteria attached to both composites in all groups, while SEM images showed thicker biofilms formed by mixed compared to S. mutans mono-culture. Even so, only S. mutans biofilm increased significantly (2-way ANOVA, p=0.05) the roughness of Tetric EvoFlow at both 10x10µm (Rq=9.7±3.2nm) and 1x1µm images (Rq=1.9±0.3nm), compared to the control (Rq[10x10]=6.4±1.7nm, Rq[1x1]= 1.2±0.2nm). Roughness of Gradia, however, did not change significantly from the control (Rq[10x10]=15±2.4nm, Rq[1x1]= 1.8±0.5nm) by any biofilm.
Conclusions: Composite containing Bis-GMA might be more susceptible to the degradation by S. mutans. However, the observed roughness changes do not seem to lead to a higher bacterial accumulation.
Therefore, the objective of this study was to investigate the effect of mono- and multispecies biofilms on surface roughness and topography of two dental composites with different composition regarding resin matrix and fillers.
Methods: Disk-shaped specimens of a paste-like, Bis-GMA free (Gradia Direct Anterior, GC), and flowable, Bis-GMA-based composite (Tetric EvoFlow, Ivoclar Vivadent) were prepared using polytetrafluoroethylene molds and glass slides. After ethylene-oxide sterilization (38°C), specimens (n=3) were incubated with 1) Streptococcus mutans, 2) mixed bacterial culture (Streptococcus mutans, Streptococcus sanguinis, Anctinomyces naeslundii and Fusobacterium nucleatum) or 3) sterile bacterial growth medium (control). Following 6-week incubation, the attached biofilms were collected for qPCR assessment, after which the specimens were cleaned and analyzed with atomic force microscope (AFM) at lower (10x10µm) and higher resolution (1x1µm) with regard to surface roughness (Rq) and topography. Additional samples with attached biofilms were observed with scanning electron microscope (SEM).
Results: qPCR analysis revealed a similar amount of bacteria attached to both composites in all groups, while SEM images showed thicker biofilms formed by mixed compared to S. mutans mono-culture. Even so, only S. mutans biofilm increased significantly (2-way ANOVA, p=0.05) the roughness of Tetric EvoFlow at both 10x10µm (Rq=9.7±3.2nm) and 1x1µm images (Rq=1.9±0.3nm), compared to the control (Rq[10x10]=6.4±1.7nm, Rq[1x1]= 1.2±0.2nm). Roughness of Gradia, however, did not change significantly from the control (Rq[10x10]=15±2.4nm, Rq[1x1]= 1.8±0.5nm) by any biofilm.
Conclusions: Composite containing Bis-GMA might be more susceptible to the degradation by S. mutans. However, the observed roughness changes do not seem to lead to a higher bacterial accumulation.