Degradation of acidic solutions and bacterial
Background: Surface roughness allows dental biofilm to be formed in greater quantities and more quickly on rough surfaces. Biofilm maturation has clinical implications because it intensifies the presence of pathogenic microorganisms. Methods: The specimens (diameter = 10 mm ⁄ thickness = 2 mm) were stored in deionized water for 7 days, and divided into immersion groups (n=10): Coffee, G1; Coca Cola, G2; H2OH lemon refrigerant, G3; immersed for 7 days. Mass (g) was analyzed with a digital scale, and Ra roughness (μm) by readouts on specimen surfaces using a roughness meter. Microbial adherence analysis was performed from a microbial suspension of Streptococcus mutans dispensed in test tubes containing TSB broth with the addition of 1% glucose. Five specimens of the each group were introduced into the mentioned test tubes and incubated at 37ºC/24h. The specimens were then washed in a buffered saline solution (PBS). After this, they were placed in test tubes containing glass micropearls +1 ml of PBS and agitated for 60 second (Phoenix agitator). The microbial suspension was diluted in PBS and plated in triple spots on the surfaces of TSA plates. Results: There was increase in roughness (G1.T0=0.1861, G1.TF=0.2091; G2.T0=0.2209, G2.TF=0.2262; G3.T0=0.1705, G3.TF=0.1756) showing no significant differences (signal test, p>0.05). There was loss of mass, being significant (Student’s-t test p>0.05) for Group G2 (G2.T0=0,3980, G2.TF=0,3843). Adherence of Streptococcus mutans forming colonies was observed (UFC/mg): 7,17 x 104,G1; 3,83 x 104, G2; 2,83 x 104, G3, showing no significant differences among the groups (Kruskal-Wallis test, p>0.05). Conclusion: It was concluded that acidic solutions compromise the surface quality of indirect polymeric matrix, propitiating an irregular structure that compromises the quality of the restoration and favor bacterial plaque formation.
Keywords:Composite resin, acidic solutions, surface properties, microbial adherence