Objectives: This study investigated protein compositions as a substitute for human saliva for initial in-vitro adhesion tests of Streptococcus mutans to dental materials.
Methods: 600 samples (diameter 10mm, 2mm thick) of a ceramic (Empress 2), a compomer (Compoglass; both Ivoclar-Vivadent, FL), a veneering composite (Sinfony, 3M Espe), a NiCrMo alloy (giroband, Amann- Girrbach, D) and a denture base material (Palapress (Heraeus Kulzer, D) were made according to the manufacturers instructions. Glass plates were used as a reference. All samples were polished (paste, Ivoclar, G) and the roughness (Perthometer SP6, G) and contact angle were determined. After incubating (n=40) for 2 hours (37°C) in a.) protein composition (Albumin, α-Amylase, Immunglobin A, Lysozym and Mucin in phosphate buffered saline (PBS)), b.) human saliva or c.) PBS (control=1), all specimens were exposed to S. mutans ATCC 25175 (37°C, DSMZ, G). The bacterial adhesion was quantified with the fluorescence testing device (Resazurin-reduction; Fluostar Optima, G) in relation to the PBS control. Medians and 25%/75%-percentiles were calculated. Statistics: Mann-Whitney U-test (p<0.05).
Results:
| Relative amount of bacteria | Ceramic | Compomer | Composite | Alloy | Denture base | Glass |
| Human saliva | 0.92 (0.27/1.92) | 1.40 (0.59/4.06) | 1.2 (0.56/1.95) | 0.74 (0.44/1.15) | 0.90 (0.50/1.61) | 0.89 (0.50/1.32) |
| Protein mixture | 0.38 (0.00/1.02) | 1.37 (0.78/3.35) | 1.03 (0.66/2.03) | 1.04 (0.67/1.36) | 0.84 (0.37/1.56) | 1.09 (0.66/1.58) |
| PBS | 1 | |||||
Conclusion: All materials but ceramic showed no significant different bacterial adhesion on saliva or protein surface. The protein mixture seems to be a practical substitute for human saliva in bacterial adhesion tests, with the advantage of constant quality and easy availability.