Adhesion of Streptococcus mutans to different restorative materials

ABSTRACT: Adherence of oral bacteria to the surface of dental restorative materials is considered
an important step in the development of secondary caries and periodontal disease. The aim of this
study was to investigate and compare the adherence of different restorative materials to Streptococcus
mutans strain (CCUG35176) in order to ascertain possible differences. The materials tested
ranged across different classes including: flowable composites (Gradia Direct LoFlo; Filtek Supreme
XT Flowable), anterior composites (Gradia Direct Anterior), universal composites (Filtek Supreme
XT), packable composites (Filtek Silorane; Filtek P60), glass-ionomers (Fuji IX Gp Extra; Equia) and
a control reference material (Thermanox plastic coverlips). Bacterial suspension was deposited onto
each material and the adhesion was evaluated trough the colony forming units (CFUs) determination.
Packable silorane-based composite was found to be less adhesive than posterior packable composite
P60, flowable composites and glass ionomers. The fluoride of glass ionomers did not prevent the attachment
of S. mutans; furthermore, after roughness analysis and SEM investigations, the hypothesis
that the difference in bacterial adhesion can be determined by the particular surface chemistry of the
material itself as well as by different electrostatic forces between bacteria and restorative surfaces
must be given serious consideration.