Influence of Biofilm on the Color Stability of Calcium Silicate Materials

Background: There are limited data on color stability of calcium silicate-based materials influenced by oral bacterial biofilm. This study aimed to evaluate color changes of three calcium silicate-based materials affected by biofilm formation.

Methods: ProRoot white MTA (Dentsply, USA), Biodentine (Septodont, France), Theracal LC (Bisco, USA), and Z-250 composite (3M ESPE, USA) samples were assessed. Materials were mixed or light-cured according to the manufacturers’ instructions. Disk-shaped specimens of each group (6.35 mm diameter by 2 mm thickness) were prepared. Pooled saliva was collected and prepared from 10 healthy donor (5 female and 5 male) and the prepared saliva (2 ml) was inoculated into the well which contained the specimens. The plates were incubated at 37℃ in anaerobic chamber. The medium was changed every 2 days with BHI broth containing 2% sucrose and 1% mannose. A spectrophotometer was used to determine the CIE Lab of each specimen using three samples for each group at 0, 3, and 7 days. Color differences between the specimens at different days were calculated and compared.

Results: All materials exhibited significant discoloration with biofilm formation. ProRoot white MTA showed the greatest color changes compared with other materials. Biodentine showed color changes mainly at 3 days with no further serious changes between 3 and 7 days. The color changes for Theracal LC was comparable to those for Z-250 at 3 days and to those for Biodentine at 7 days.

Conclusions: Calcium silicate-based materials under the influence of oral bacterial biofilm showed differences in color of the tested specimens during a period of 7 days. However, the color changes in Biodentine and Theracal LC were smaller than those in ProRoot white MTA.