Adsorption of salivary and serum proteins, and bacterial adherence on titanium and zirconia ceramic surfaces.

OBJECTIVES: The aim of this study was to determine the pattern of salivary and serum proteins present in pellicles formed on titanium (Ti) and zirconia ceramic (ZrO(2)) surfaces, and the ability of bacterial cells to adhere to the experimental pellicles. In addition, the protein profiles and bacterial binding properties of pellicles on Ti and ZrO(2) were compared to those formed on hydroxyapatite (HA) surface. METHODS: The pellicles were formed in vitro by incubating the materials with whole saliva, serum or saliva+serum. Protein composition in each of the pellicles was investigated by SDS-PAGE and immunodetection. The adherence of radiolabeled Streptococcus mutans and Actinomyces naeslundii to uncoated surfaces and experimental pellicles was determined by means of scintillation counting. Statistical analyses were done using ANOVA and Tukey's test at significance level at P<0.05. In general, the electrophoretic analysis of the pellicles formed on HA, Ti and ZrO(2) revealed few qualitative differences of the composition of proteins of the pellicles formed on HA, Ti and ZrO(2) surfaces. Pellicle components identified included amylase, IgA, IgG, albumin, fibronectin and fibrinogen. The number of S. mutans cells adhered to uncoated Ti and ZrO(2) was significantly higher than those adhered to HA (P<0.05). In contrast, lower number of A. naeslundii cells adhered to uncoated Ti and ZrO(2) than to HA (P<0.05). However, the presence of saliva and saliva+serum pellicles greatly reduced the number of S. mutans cells bound to each of the surfaces. The data showed that Ti and ZrO(2) display similar pellicle protein composition and bacterial binding properties; however, significant differences were observed when both materials were compared to HA.

The influence of mutanase and dextranase on the production and structure of glucans synthesized by streptococcal glucosyltransferases.

Glucanohydrolases, especially mutanase [alpha-(1-->3) glucanase; EC 3.2.1.59] and dextranase [alpha-(1-->6) glucanase; EC 3.2.1.11], which are present in the biofilm known as dental plaque, may affect the synthesis and structure of glucans formed by glucosyltransferases (GTFs) from sucrose within dental plaque. We examined the production and the structure of glucans synthesized by GTFs B (synthesis of alpha-(1-->3)-linked glucans) or C [synthesis of alpha-(1-->6)- and alpha-(1-->3)-linked glucans] in the presence of mutanase and dextranase, alone or in combination, in solution phase and on saliva-coated hydroxyapatite beads (surface phase). The ability of Streptococcus sobrinus 6715 to adhere to the glucan, which was formed in the presence of the glucanohydrolases was also explored. The presence of mutanase and/or dextranase during the synthesis of glucans by GTF B and C altered the proportions of soluble to insoluble glucan. The presence of either dextranase or mutanase alone had a modest effect on total amount of glucan formed, especially in the surface phase; the glucanohydrolases in combination reduced the total amount of glucan. The amount of (1-->6)-linked glucan was reduced in presence of dextranase. In contrast, mutanase enhanced the formation of soluble glucan, and reduced the percentage of 3-linked glucose of GTF B and C glucans whereas dextranase was mostly without effect. Glucan formed in the presence of dextranase provided fewer binding sites for S. sobrinus; mutanase was devoid of any effect. We also noted that the GTFs bind to dextranase and mutanase. Glucanohydrolases, even in the presence of GTFs, influence glucan synthesis, linkage remodeling, and branching, which may have an impact on the formation, maturation, physical properties, and bacterial binding sites of the polysaccharide matrix in dental plaque. Our data have relevance for the formation of polysaccharide matrix of other biofilms.

Effects of Apis mellifera propolis on the activities of Streptococcal glucosyltransferases in solution and adsorbed onto saliva-coated hydroxyapatite / Efeitos do própolis Apis mellifera nas atividades do Streptococcal Glucosyltransferases em solução e absorvido sobre hidroxyapatita coberta com saliva

Propolis, a resinous hive product collected by Apis mellifera bees, has been used for thousands of years in folk medicine. Ethanolic extracts of propolis (EEP) have been shown to inhibit the activity of a mixture of crude glucosyltransferase (Gtf) enzymes in solution. These enzymes synthesize glucans from sucrose, which are important for the formation of pathogenic dental plaque. In the present study, the effects of propolis from two different regions of Brazil on the activity of separate, purified Gtf enzymes in solution ans on the surface of saliva-coated hydroxyapatite (sHA) beads were evaluated. The EEP from Minas Gerais (MG; Southeastern Brazil) and Rio Grande do Sul (RS; Southern Brazil) were tested for their ability to inhibit the enzymes GtfB (synthesis of insoluble glucan), GtfC (insoluble/soluble glucan) and GtfD (soluble glucan). The effects of propolis on Gtf from Streptococcus sanguis (soluble glucan synthesis) was also explored...