Identification of the microbiota of maxillofacial prostheses and adjacent tissues and evaluation of the antimicrobial effectiveness of different hygiene protocols and their effects on properties of two silicones

Author(s)

Juliana Barchelli Pinheiro

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2015-11-06

Examining board members

Cláudia Helena Lovato da Silva; Aimée Maria Guiotti; Cássio do Nascimento; Luís Geraldo Vaz

• Advisor: Cláudia Helena Lovato da Silva

Abstract

The aim of this study was to identify clinically the microorganisms present in prostheses and adjacent tissues, evaluated laboratory antimicrobial action of different hygiene protocols on the main identified microorganisms and also evaluate the influence of hygiene protocols in color change, Shore A hardness, surface roughness and absorption of liquids, a new silicon (Bio-Skin) compared to the MDX 4-4210. For identification of microorganisms, 43 individuals with maxillofacial prostheses were submitted to harvesting the biofilm on the prosthesis and adjacent tissues and 38 targets species were surveyed through the Checkerboard DNA-DNA Hybridization method. The analysis of antimicrobial activity was conducted by formation of specific biofilm in six selected species. 288 specimens with pigmented makeup powder were fabricated with each material, and divided into groups for immersion in 0.12% chlorhexidine gluconate, Ricinus communis 10%, and brushing with neutral soap. As a control, one group was immersed in water. To analyze the influence of hygiene protocols on the properties of silicones, 120 circular specimens of each material were prepared (n = 10): no pigmentation (CG: control), with makeup powder (GP), opacifier (GO) or opacifier + makeup powder (GPO), and then be submitted to cleaning: EA (immersion in distilled + brushing water with mild soap - control), ERc10% (immersion in Ricinus solution communis 10% + brushing with mild soap) and ECl0 12% (immersion in chlorhexidine gluconate 0.12% + brushing with neutral soap). The hygiene period simulated one year of clinical use. The quantitative response variables were measured immediately after obtaining the specimens and after the application of hygiene protocols and the variation obtained was used in the statistical analysis. For analysis of antimicrobial hygiene protocols and color change, Shore A hardness and surface roughness, there was analysis of variance and Tukey Supplementary test for comparison of averages. For the absorbing liquid, we applied the Kruskal-Wallis test. For comparing the count microorganisms present in prostheses and adjacents tissues we used the Wilcoxon test (Signed-rank Test). To analyze the data obtained by CFU counts for analysis of antimicrobial hygiene protocols, we used two-way ANOVA and Tukey Complementary Test. All analyzes were conducted with significance level of 5%. The method of Checkerboard DNA-DNA Hybridization indicated the presence of 38 species in the prosthesis and adjacent tissue and the following microorganisms were selected: C. glabrata, S. aureus, S. mutans, E. coli, E. faecalis and P. aeruginosa. For antimicrobial analysis, 0.12% chlorhexidine gluconate was the most effective, followed by mechanical brushing, against six species. The color change was not influenced by hygiene protocols and the slightest change was found with the Bio-Skin silicone GP and GPO groups. Silicone MDX showed less variation in Shore A hardness according to the maintenance protocol ECl0,12%, while the hardness of Bio-Skin was not influenced by hygiene protocols. The variation in hardness between the two silicones were different only when subjected to ERc10% protocol. To the surface roughness, the MDX silicone showed the smallest variation of roughness. The percentage of absorption for the MDX 4-4210 silicone was not influenced by the pigment and sanitization protocols. For the Bio-Skin, the percentage of absorption was higher in GC and GO groups when subjected to EA protocol. Note that there was an interaction between pigment and maintenance protocol, where for silicone MDX, absorption was greater when subjected to ECl0,12% protocol and Bio-Skin, there was a greater percentage absorption in the GC group and GO associated with brushing and immersion in water and GP groups and GPO associated with ECl0,12% protocol. It was concluded that both prosthesis as adjacent tissues exhibit great amount of microoorganisms colonizing and that daily hygiene are essential. The immersion in chlorhexidine gluconate 0.12% and mechanical brushing protocols with neutral soap have antimicrobial activity on the main microorganisms commonly present in prosthetics and tissue and silicone MDX 4-4210 had lower CFU counts compared to Bio Skin. Both materials showed variations due to different pigmentations and hygiene protocols, however, they were discreet and within acceptable clinical standards. Minor changes were observed when the materials were exposed to immersion protocols chlorhexidine gluconate 0.12% and brushing with neutral soap. (AU)

• FAPESP's process: 12/24853-0 - Identification of the microbiota of facial prostheses and laboratory evaluation of the effectiveness of different hygiene solutions.
• Grantee: Juliana Barchelli Pinheiro
• Support Opportunities: Scholarships in Brazil - Doctorate