THE ABRASIVENESS OF TOOTHPASTES ON PERMANENT TEETH

Abstract

AIM: To investigate and compare the mineral and surface loss on an enamel surface by brushing with three types of toothpastes with different abrasivity.

METHODS: Four natural premolar teeth were used. The experimental surfaces were the mesial and distal surfaces (8 surfaces in total). Three different toothpastes with low, medium, and high RDA values were allocated randomly to one tooth, and one tooth was brushed with water only. The two proximal surfaces from the same tooth were embedded in an acrylic resin block (3x3mm), and both surfaces of the same tooth were brushed with the same toothpaste. Baseline scans were taken with X-ray Microtomography (XMT) and Non-contact Profilometry (NCP) prior to the abrasion technique using an automatic brushing machine. The resin blocks were securely fixed to immobilise it during brushing. Toothbrushing was implemented using a flat medium textured filaments toothbrush, and one mL of slurry toothpaste was applied to the toothbrush. A 200 gram loading was applied on the top of the toothbrush head. 40,000 brushing cycles were performed for each sample. In every 2000 cycles, samples were washed with running water and 1mL of new slurry toothpaste was added to ensure a sufficient amount of toothpaste throughout the experiment. Post-abrasion scans were taken from x-ray microtomography (XMT) and non-contact profilometry (NCP) to compare enamel loss in relation to toothpaste abrasivity.

RESULTS: The amount of enamel loss was significantly higher in the tooth brushed with high RDA value toothpaste T3H than the tooth brushed with medium RDA value toothpaste T2M (p value= 0.003). The control tooth T4C had a significantly lower enamel loss than T2M and T3H (p value<0.001). The highest average roughness value (Ra) difference was found with T2M, medium RDA toothpaste.

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CONCLUSION: The results suggest that increased enamel surface loss was related to higher toothpaste abrasivity. Other factors, such as local microstructural differences, might have an influence on the enamel surface roughness after brushing with an abrasive toothpaste.