Salivary responses to chewing mastic resin and parafilm and inhalation of mastic- and α-pinene-derived volatiles in healthy young adults

Salivary secretion is essential for maintaining oral homeostasis, and its modulation by sensory stimuli provides insight into salivary gland function. Mastic resin, obtained from the Pistacia lentiscus tree, is rich in terpenes such as α-pinene, which may influence salivary responses through gustatory, olfactory, or mechanosensory pathways. In addition, α-pinene may modulate salivary secretion through cholinergic pathways and may therefore have potential as a natural sialagogue. We aimed to evaluate how healthy young adults respond to masticatory and olfactory stimulation by assessing the changes in salivary flow rate and pH following exposure to mastic resin, a tasteless chewing control, and volatiles of mastic oil or α-pinene. The salivary flow and pH were measured in healthy individuals (n = 30) before and after chewing mastic resin or parafilm (control), or after inhalation of mastic or α-pinene oil volatiles delivered via nasal inhalers. Both masticatory stimuli increased salivary flow (p < 0.0001). Chewing mastic resin induced a greater increase in salivary flow than chewing parafilm (p < 0.0001). Olfactory exposure to mastic oil and α-pinene also elicited significant increases in salivary flow (p ≤ 0.01). Furthermore, pH increased after chewing mastic resin and parafilm (p < 0.0001) and α-pinene inhalation (p < 0.05), but not after inhalation of mastic volatiles. In conclusion, healthy young adults demonstrated clear salivary responses to both chewing and odour stimuli derived from P. lentiscus. The findings demonstrate that mastic resin and its volatile components can modulate salivary secretion through multiple sensory pathways, and they warrant further investigation of mastic-derived stimuli as potential modulators of salivary secretion, especially in individuals with dry mouth.