Influence of the Amount of Toothpaste on Cleaning Efficacy: An In Vitro Study

Abstract

Objectives: The aim of this in vitro study was to test the influence of the amount of toothpaste on enamel cleaning efficacy.

Materials and methods: The hydrated silica-based test toothpaste (radioactive dentin abrasion: 60.19 ± 1.35) contained all ingredients of a regular fluoride toothpaste. The cleaning efficacy of four different toothpaste amounts (1.00 g, 0.50 g [both "full length of brush"], 0.25 g ["pea-size"], and 0.125 g ["grain of rice-size"]) diluted in 1.00 mL water were each tested for different brushing times (10, 30, 60, 120, 180, and 300 seconds) using a standardized staining model on human molars with a brushing machine. Photographic documentation and colorimetric measurements were conducted, respectively, initially, after staining and after each brushing step. Colorimetric measurements were used to calculate the stain removal (in %).

Statistical analysis: Results were analyzed by one-way analysis of variance with post hoc Tukey test and Levene's test for analysis of homogeneity of variance. The level of significance α was set at ≤ 0.05.

Results: The cleaning efficacy decreased significantly when using smaller toothpaste amounts. Stain removal after 120 seconds brushing time was: 77.4 ± 5.0% (1.00 g toothpaste), 75.7 ± 3.4% (0.50 g toothpaste), 54.1 ± 6.7% (0.25 g toothpaste), and 48.2 ± 7.1% (0.125 g toothpaste), respectively.

Conclusion: In this in vitro study the cleaning efficacy of a medium-abrasive, hydrated silica-based toothpaste was analyzed. Note that 1.00 g toothpaste showed for all brushing times a significantly higher cleaning efficacy than 0.25 g toothpaste and 0.125 g toothpaste.

Fig. 1

Overview about the staining procedure used in this study.

Fig. 2

Images of enamel surfaces before staining, after staining, and post-stain removal, brushing was performed for different brushing times (10, 30, 60, 120, 180, 300 seconds) and toothpaste amounts: 1:1 (maximum “full length of brush”), 1:2 (minimum “full length of brush”), 1:4 (“pea-size”), and 1:8 (“grain of rice-size”).

Fig. 3

Stain removal efficacy (in % stain removal) for stained enamel specimens after brushing for up to 300 seconds with different toothpaste amounts: 1:1 (maximum “full length of brush”), 1:2 (minimum “full length of brush”), 1:4 ( “pea-size”), and 1:8 (“grain of rice-size”).