Effect of lozenge surface texture, taste and acidity on salivary flow rate: A crossover preclinical trial in healthy subjects

Abstract

Dry mouth is a multifaceted condition which is caused by reduced salivary secretion. This study aimed to evaluate and compare the effects of different lozenge surface textures, tastes and acidity levels on stimulated salivary secretion for increased oral moistening in participants without hyposalivation. This randomized, double-blind, clinical crossover trial with before and after comparison involved 33 healthy volunteers. Five lozenges, including a baseline control (C), apple (A), sour (S), sour apple (SA) and granular pectin (P) were tested on five different days with all the subjects. Salivary flow, pH value, and subjective feeling (visual analog scale) were measured before and after consuming the lozenge each day. Throughout all trial days the unstimulated whole salivary flow (UWSF) averaged 0.65 ± 0.26 ml/min. Lozenges S, SA, and P showed higher stimulated whole salivary flow (SWSF) than C (P < 0.001) by more than 0.5 ml/min. Lozenge P, with a rough surface, demonstrated the highest difference between UWSF and SWSF, 2.41 ± 0.69 ml/min. The stimulated saliva with the lozenges containing acidifiers (S, SA and P) was more than 1.4 pH units lower compared to lozenges C and A (P < 0.001). Subjects reported the strongest subjective feeling of increased saliva with lozenges SA and P. Overall lozenges SA and P provided the best objective results in enhancing salivary flow rate and subjective feeling of increased salivary flow.