Impact of toothpaste brushing of denture material on bacterial attachment

Objectives: To study the effect of brushing acrylic denture material with toothpastes on bacterial attachment of an early colonizer organism (Streptococcus oralis).

Methods: Swatches of acrylic denture material were treated to give a range of surface roughness (Ra) values, 0.05-1.14microns. Treatments included hand and machine brushing and with different dentifrices. The brushed acrylic samples were surface sterilized, dried, immersed in sterile artificial saliva inoculated with S. oralis (NCTC 11427) from an overnight culture and incubated at 37°C for periods of 0 to 300 minutes. After incubation, the acrylic samples were washed, fixed in methanol and stained with acridine orange solution. Denture acrylic samples were assessed quantitatively for bacterial attachment using microscopy and Image Pro software. The number of attached bacteria was converted into percentage area of field covered by cells.

Results: Increasing Ra value for the denture material surface resulted in an increase in bacterial attachment. Statistical significance at p<0.05 was shown between a control acrylic surface (Ra value 0.07) and dentifrice brushed samples (Ra value 0.38).

Conclusions: This study shows for the first time that scratches resulting from brushing of denture material with toothpaste cause a statistically significant increase in attachment of an early colonizing bacterial species, when compared to control.

Research was conducted and funded by GlaxoSmithKline Consumer Healthcare