Effect of Inula viscosa on the pellicle’s protective properties and initial bioadhesion in-situ

• Rinsing with Inula viscosa tea was performed in-situ.
• Erosive attack was induced by incubation of enamel samples in HCl ex-vivo and calcium- and phosphate loss were determined photometrically.
• Fluorescence microscopic approaches yielded a significant reduction of adherent bacteria and glucans after rinse with Inula viscosa tea.
• Transmission electron microscopy indicated a modification of the pellicle’s ultrastructure but no enhanced protection against erosive noxae.

ObjectivesThe present in situ study investigated the effect of Inula viscosa tea on the pellicle’s acid protective properties and on initial oral biofilm formation.DesignBiofilm formation was performed on bovine enamel slabs on individual maxillary splints. Following 1 min of pellicle formation, eight subjects rinsed for 10 min with Inula viscosa tea and the splints remained for 8 h intraorally. Samples carried after 1-min rinsing with CHX (0.2%) or without rinse served as controls. BacLight™ staining, 4′,6-diamidino-2-phenylindole (DAPI)-staining and fluorescence in situ hybridization (FISH) were used for fluorescence microscopic detection of adherent bacteria. For investigation of acid protective properties, three subjects rinsed for 10 min with Inula viscosa tea after 1 min pellicle formation and kept the splints intraorally for further 19 min. Physiological 30-min pellicles and native enamel samples served as controls. After HCl incubation of the samples ex-vivo over 120 s (pH 2.0, 2.3, 3.0) calcium- and phosphate release were quantified photometrically. Potential influences on the pellicle’s ultrastructure by Inula viscosa tea were evaluated by transmission electron microscopy (TEM).ResultsApplication of Inula viscosa tea yielded a significant reduction of adherent bacteria on all enamel samples as detected by fluorescence microscopy. For calcium- and phosphate release no significant effect was recorded. TEM investigation indicated a modification of the pellicle’s ultrastructure, but no enhanced protection against erosive noxae.ConclusionRinsing with Inula viscosa tea influences the bacterial colonization on enamel in situ over 8 h but has no impact on acid protective properties of the pellicle.