J Korean Acad Oral Health.  2023 Dec;47(4):160-166. 10.11149/jkaoh.2023.47.4.160.

Evaluation of toothpaste abrasivity using acrylic and spectrophotometry

• Jeong SH
• Byon MJ
• Jun EJ

• KMID: 2550168
• DOI: http://doi.org/10.11149/jkaoh.2023.47.4.160

Abstract

Objectives
This study aimed to develop a method for objectively evaluating toothpaste abrasivity, enabling a direct comparison between different toothpastes.
Methods
Nine commercially available toothpaste variants were selected, and 8 mm thick acrylic specimens were allocated to each toothpaste treatment group (n=7). A control group without toothpaste was also included. Specimens and toothbrushes were mounted on the V8 Cross brushing machine, and toothpaste (0.05-0.1 g) was applied for 20 strokes under a 200 g load and 1 Hz speed. The surface wear was measured at an absorbance of 600 nm in a UV-Vis spectrophotometer. Specimens were then photographed with a polarized light microscope, and the gray value of the worn brushed part was obtained through image analysis using Image J software. A one-way ANOVA followed by Bonferroni’s post-hoc test was employed for analyzing absorbance and gray value differences among the toothpaste groups. The correlation between absorbance and gray value was assessed using Pearson’s correlation analysis.
Results
Significant differences were noted in absorbance and gray values across the toothpaste groups (P<0.05), and a strong correlation was observed between the absorbance and the values from the images analyzed (r=0.948, P<0.001). The wear rankings based on absorbance and image analysis values were mostly the same.
Conclusions
This study introduces a direct and objective method for evaluating toothpaste abrasion, offering users objective information on different toothpaste types.

Keyword

Acryl; Polarized light microscopy; Spectrophotometer; Toothbrushing; Toothpaste abrasivity

Figure

• 

  Fig. 1 Polarized light images (top) and gray value graph (bottom) of a non-brushed and brushed acrylic surface (the left side of the image depicts the unbrushed area, whereas the right side corresponds to the toothbrushed area).

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  Fig. 2 Gray value graph depicting a specific 600-pixel area of both a non-brushed and brushed acrylic surface (left) and absolute value of the difference between the gray values of the non-brushed and brushed acrylic surface (right).

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