In vitro biofilm formation and viability of human gingival fibroblasts (FMM-1) on new ceramic materials

Author(s)

Amanda Maria de Oliveira Dal Piva

• Document type: Master's Dissertation
• Press: São José dos Campos. 2017-01-31.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Ciência e Tecnologia. São José dos Campos
• Defense date: 2017-01-19
• Advisor: Marco Antonio Bottino; Lilian Costa Anami

Abstract

This study evaluated the morphology of two ceramic materials recently introduced on the market, as well as the formation of heterotypic biofilm and the viability of human gingival fibroblasts (FMM-1) in contact with these materials after glazing or polishing. For this, 46 blocks (4.5x4.5x1.5 mm) of each ceramic were made: high translucency zirconia partially stabilized by yttrium (HT) and lithium silicate reinforced by zirconium (SUP). The blocks were sintered/crystallized and surfaces were standardized with glaze application (subgroup “g”). The surface roughness (Ra and RSm) was evaluated through a contact rugosimeter (n=20) and qualitatively by profilometry (n=2). After sterilization, specimens were contaminated for heterotypic biofilm formation with association of S. mutans, S. sanguinis and C. albicans during 16 h of formation (n=8) and the biofilm was quantified by counting the colony forming units (CFU/mL) and analyzed by scanning electron microscopy (SEM). The viability of FMM-1 fibroblasts was evaluated by MTT assay. 5 samples (15x15x1.5 mm) were prepared in a similar way and used to determine the surface free energy (SFE) by goniometry. Then, the non-destroyed specimens (n=26) were resubmitted to the sandpaper polishing and finished as recommended by the manufacturer to evaluate the polished surfaces (subgroup “p”) under all analyzes in study. Roughness data was evaluated using the nonparametric Kruskal-Wallis, Dunn and Mann-Whitney tests. SFE, MTT and CFU results were evaluated by ANOVA and Tukey’s test, and MTT data was also submitted to t test. For all tests, it was considered an alfa value of 95%. Roughness was influenced by materials and surface treatments (Ra p=0,001; RSm p=0,0002). HTg ceramic presented, on average, higher and less spaced grooves than others. Both material and surface factors influenced the SFE (p=0,001), all materials presented hydrophilic behavior, however HTp presented higher SFE. The interaction of surface and micro-organism factors influenced the CFU (p=0,00), Streptococcus showed more adherence on glazed surfaces and C. albicans presented less adherence on polished surfaces. MTT assay demonstrated initial (24 h) cytotoxic behavior to polished surfaces, which was not repeated within the period of 7 days. The profilometry evidenced the more homogeneous surface morphology of polished samples. Except for HTg, the SEM images showed homogeneous surfaces, and on the contaminated specimens, it was observed the presence of Streptococcus and C. albicans. It could be concluded that glazed surfaces presented a greater roughness and tend to accumulate more biofilm. Polished surfaces present high SFE, however, are temporarily cytotoxic. (AU)

• FAPESP's process: 15/13322-1 - New ceramic materials: evaluation of biofilm formation and viability of human gingival fibroblasts (FMM-1)
• Grantee: Amanda Maria de Oliveira Dal Piva
• Support Opportunities: Scholarships in Brazil - Master