Comparative Mucosal Wetting Capacity of Novel and Commercial Saliva Substitute Formulations: An in vitro Study

Abstract

Purpose: This study evaluated the effectiveness of novel, inexpensive saliva substitute formulas (Rangsit University (RSU) preparation) in maintaining mucosal wetness compared with commercial products. Materials and Methods: In vitro experiments were conducted using swine tongues to assess the wetness of various RSU saliva substitute solutions and gels, with four flavors each (sweet mint, sweet vanilla, sweet-sour mint, and sweet-sour lemon), compared with water, hospital-based mouth rinse from a government dental school, and commercial products (Biotene® mouthwash and GC Dry Mouth Gel®). The wetness was measured at baseline and at 0, 10, 20, 30, 60, and 120 minutes using a digital moisture analyzer. Results: All saliva substitutes consistently maintained a higher relative wetness than water, particularly beyond 60 minutes (p < 0.001). RSU solutions with a sour flavor (sweet-sour mint and sweet-sour lemon) had a similar wetness to commercial saliva substitute mouthwash at all times. These solutions were more effective in maintaining higher relative wetness over time than those without a sour flavor (sweet mint and sweet vanilla) (p < 0.05) and provided more wetness than the hospital-based mouth rinse at 120 minutes. The RSU solution formula also provided comparable wetness to RSU gel preparation at every time point. While RSU gel formulas initially provided comparable wetness to water, they maintained significantly higher wetness at 60 minutes (p = 0.029) and 120 minutes (p = 0.002). These results were similar to those of commercial saliva substitute gel, which maintained stable wetness since application up to 120 minutes (p = 0.052). Conclusion: Our novel saliva substitute formulas show similar effectiveness to commercial products in maintaining mucosal wetness. These inexpensive products could be a viable alternative for patients with dry mouth who cannot afford commercial formulations.