Influence of saliva substitute pellicles on initial Streptococcus mutans adhesion

Introduction: Saliva substitutes are commonly used for relieving symptoms caused by xerostomia, and are intended to prevent caries formation. This study aimed to evaluate the influence of various saliva substitute pellicles on the initial adhesion of Streptococcus mutans to different substrata.

Material and Methods: 70 specimens each of a denture base resin (Palapress vario, Heraeus Kulzer, Hanau, G) and a veneering composite (Sinfony, 3M Espe, Seefeld, G) were prepared and polished, and surface free energy was determined. Glass plates were used for reference. Specimens were rinsed with commercial saliva substitutes (Aldiamed, Salinum, Saliva natura, Saliva orthana), a self-developed protein solution or PBS for 2h at 37°C, and subsequently with Streptococcus mutans ATCC 25175 suspension for 4h at 37°C in a dynamic flow chamber assay. Adherent streptococci were quantified using a fluorometric assay, and ranked in relation to PBS incubation (mean fluorescence intensity = 1). Means and standard deviations were calculated. Statistics: Two-way factorial ANOVA (p<0.01), Tukey-Kramer multiple-comparison test (p<0.05).

Results:

	Denture base	Veneering composite	Glass
	Mean (SD)	Mean (SD)	Mean (SD)
Protein mixture	1.24 (.37)	.93 (.88)	2.09 (1.64)
Saliva orthana	1.58 (.77)	1.02 (.70)	2.39 (1.16)
Aldiamed	1.43 (.60)	.53 (.18)	1.37 (.95)
Saliva natura	1.59 (.72)	.44 (.37)	.58 (.43)
Salinum	2.59 (1.48)	.80 (.12)	1.13 (.38)

Two-way factorial ANOVA showed that substrata as well as the saliva substitutes influenced the adhesion of Streptococcus mutans significantly. Multiple comparisons revealed few differences in streptococcal adhesion between some of the various saliva substitute coatings, and partially these differences were dependent on substratum material.

Conclusion:

Within the limitations of this research it can be concluded that some saliva substitutes differ in their influence on initial Streptococcus mutans adhesion in dependence on substratum material. Future studies should further elucidate the impact of substratum properties on streptococcal adhesion after saliva substitute coating.