Influence of Slurry Diluents on Toothpaste Efficacy Against Erosive Tooth Wear: In Vitro and In Situ Studies

Area of Science:

• Biomaterials Science
• Dental Research
• Materials Science

Background:

• Toothpaste slurries utilize various diluents for in vitro and in situ erosive tooth wear studies.
• Understanding diluent influence is crucial for accurately assessing toothpaste anti-erosive potential.

Purpose of the Study:

• To evaluate how different diluents affect the anti-erosive properties of toothpastes with diverse active agents.
• To compare the efficacy of in vitro versus in situ conditions using various diluents.

Main Methods:

• Bovine enamel specimens were subjected to a 5-day erosion cycle with different diluents (deionized water, remineralizing solution, human saliva) and toothpaste formulations.
• Toothpastes included placebo, sodium monofluorophosphate (MFP), sodium fluoride (NaF), stannous fluoride + sodium fluoride (NaF/SnF₂), and chitosan + fluoride (Chi/NaF/AmF).
• Surface microhardness (SMH) and tissue loss were measured to assess anti-erosive potential.

Main Results:

• In situ human saliva as a diluent consistently yielded the highest SMH and lowest tissue loss across all tested toothpastes.
• Stannous fluoride + sodium fluoride (NaF/SnF₂) and chitosan + fluoride (Chi/NaF/AmF) formulations showed superior anti-erosive outcomes when combined with human saliva in vitro.
• For other toothpaste formulations, no significant differences in outcomes were observed between different in vitro diluents.

Conclusions:

• The choice of diluent significantly influences the outcomes of in vitro and in situ tooth wear studies.
• Toothpastes containing stannous fluoride, chitosan, and fluoride demonstrate the most substantial anti-erosive potential.
• In situ human saliva provides a more representative and effective environment for evaluating anti-erosive toothpaste efficacy.