Influence of titanium nitride by cold-plasma on formation and development of multiespecies biofilms

Author(s)

Indira Moraes Gomes Cavalcanti

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2013-06-21

Examining board members

Altair Antoninha Del Bel Cury; William Custodio; Karina Gonzales Silverio

• Advisor: Altair Antoninha Del Bel Cury

Abstract

Surface treatments that alter titanium properties titanium are performed on dental implants in order to improve the cell signalization and bone formation. Although, in certain clinical situations, the surfaces exposed to oral cavity covered by acquired-pellicle (AP) may become substrates for development of biofilms associated with inflammatory diseases as periimplantitis. Given this observation, the aims of this study were (i) to characterize the surface properties of titanium nitride by cold plasma as roughness, topography, chemical composition and surface free energy (SFE), (ii) determine the protein profile of AP adsorbed to the surfaces (iii) evaluate the influence of surface treatment on formation and development of multispecies biofilms. For the study, titanium discs grade IV received polish and finish and were randomly allocated to control (Ti) and experimental TiN (nitride by cold-plasma) groups. The surfaces were characterized by scanning electron microscopy (SEM) and roughness and topography determined by Atomic Force Microscopy (n = 4). The SFE was evaluated using the acid-base technique and read in goniometer (n = 9). The surface chemical composition was determined by x-ray photo-electron spectroscopy (XPS) (n = 4). Then, the discs were immersed in saliva for AP formation per 2 hours and again the SFE was determined (n = 6). The AP protein profile was determined by mass spectrometry LC-MS/MS (n = 18). A biofilm composed by five bacteria and one fugal (Candida albicans, Veillonella dispar, Streptococcus mutans, Streptococcus oralis, Actinomyces naeslundii and Fusobacterium nucleatum) was conducted for 64.5 hours on coated-discs. After this period, the viable cells of biofilms were determined (n = 12). The biofilms topography and organization were analyzed by SEM and by confocal laser microscopy. The data of viable cells and protein profile were evaluated statistically by Student's t test and SFE data by two-way ANOVA followed by Tukey's test with a significance level of 5%. The results showed no difference between the properties of roughness and topography in groups. A high peak of nitrogen was detected in the chemical composition of the nitride surface. The treatment did not alter the SFE, that increased in the presence of AP (p <0.001). Different protein adsorbed to nitride surface. The amount of viable cells in the biofilm formed on both surfaces was similar (p = 0.416), confirmed by microscopies. The number of viable cells of Streptococcus oralis and Fusobacterium nucleatum were higher in TiN. It was concluded that the cold plasma nitriding did not alter the titanium surface properties and did not affect the amount of biofilm. However, it increased the counts of Fusobacterium nucleatum and Streptococcus oralis and selected different proteins in AP (AU)

• FAPESP's process: 11/03242-0 - Development of a multispecie biofilm on surface modified titanium used in oral rehabilitation with implants
• Grantee: Indira Moraes Gomes Cavalcanti
• Support Opportunities: Scholarships in Brazil - Master