Extrinsic Stain Removal and Protection Effect of Toothpaste Containing Sodium-Tripolyphosphate

Objectives: To evaluate the extrinsic stain removal and protection efficacy of toothpaste containing sodium-tripolyphosphate(STPP)
Methods: Sixty human-tooth-enamel-specimens embedded in polymethyl-methacrylate blocks were prepared and randomly assigned to four groups (SR1, SR2, SP1 and SP2; n=15), regarding to tested protocols; stain removal(SR) and stain protection(SP) and toothpastes used in this study as control(1) and STPP-contained(2) toothpaste. The lightness values(△L) of all specimens were measured using the colorimeter (NR110, Shenzhen 3nh) at baseline, standard stain and at 7, 14 and 21 days of tooth brushing. After baseline △L measurement, all specimens were immersed in black-tea-solution(1g/L) for 7 days in-order-to create the standard stain. Then each group was scheduled brushing protocol using an electrical toothbrush with saturated-toothpaste-solution for 10s, twice-a-day. To evaluate the stain removal effectiveness, all specimens of group SR1&SR2, were stored in 37°C deionized water during experimental period. In contrast, all specimens of group SP1&SP2 were immersed in black-tea-solution(30min) after each time of tooth brushing, then stored in deionized water. The mean lightness and percentage of change in lightness between each period were analyzed using one-way ANOVA and independent paired t test (p<0.05).
Results: For the stain removal protocol, using either the control or STPP-contained toothpaste at least 14days exhibited significantly higher△L compared to those of standard stain. Moreover, the △L after 21days tooth brushing shown no significant difference to those at baseline. On-the-other-hand , for the stain protection protocol, SP1&SP2 revealed a significantly decreased of △L compared to those of standard stained time-after-time. However, brushing with STPP contained-toothpaste exhibited the significantly lower percentage of change in lightness compared to those of control toothpaste in all periods of routinely brushing.
Conclusions: STPP contained-toothpaste shown higher efficacy to protect the stain attachment significantly. However, the control and STPP contained-toothpaste had comparable efficacy to remove the extrinsic stain.