Effects of Nigella sativa Oil Rinsing on Salivary pH, Volume, and Protein Concentration: A Pilot Repeated-Measures...

Background This study evaluated the effects of saline and Nigella sativa oil rinsing on salivary pH, volume, and protein concentration at different rinse durations and assessed their potential implications for oral homeostasis. Rinse durations will be extended to reflect the timeframes commonly used by patients during oil-pulling practices. Methodology A total of 10 healthy adults (two males, eight females) participated in this repeated-measures pilot study. Each participant served as their own control, completing saline and N. sativa oil rinsing protocols at one-, five-, and ten-minute durations. Saliva samples were collected after each rinse for pH and volume analysis. Salivary protein concentration was determined using NanoDrop spectrophotometry and reported descriptively. Salivary pH and volume data were analyzed using two-way repeated-measures analysis of variance (ANOVA) with Šídák multiple-comparisons testing. Statistical significance was established at a p-value <0.05. Results Salivary pH demonstrated a significant effect of rinse duration (F(1.775,31.96) = 10.09, p = 0.0006), but no significant treatment effect (p = 0.5000) or time-by-treatment interaction (p = 0.5641). Salivary volume demonstrated significant effects of rinse duration (F(1.804,32.48) = 176.2, p < 0.0001), treatment (F(1,18) = 8.738, p = 0.0085), and time-by-treatment interaction (F(1.804,32.48) = 50.10, p < 0.0001). Post hoc analysis identified greater salivary volume following N. sativa rinsing compared with saline at the one-minute rinse duration (adjusted p < 0.0001), with no significant differences observed at five or ten minutes. Mean salivary protein concentrations were descriptively higher following N. sativa rinsing across all rinse durations, demonstrating fold increases of 5.04×, 2.83×, and 2.51× at one, five, and ten minutes, respectively. Conclusions Rinse duration significantly influenced salivary pH and volume, while N. sativa oil produced an early increase in salivary secretion compared with saline. These findings provide preliminary evidence that N. sativa oil may influence short-term salivary physiology and support further investigation into its potential role in oral homeostasis.