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Evaluation of microbial adhesion, wettability and effect of hygiene protocols on physical properties, mechanical properties and microbial load of multispecies biofilm on acrylic resin surface for impression of base and complete denture teeth

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Author(s):
Beatriz de Camargo Poker
Total Authors: 1
Document type: Master's Dissertation
Press: Ribeirão Preto.
Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
Defense date:
Examining board members:
Cláudia Helena Lovato da Silva; Maurício Malheiros Badaró; Ana Carolina Pero; Camila Tirapelli
Advisor: Cláudia Helena Lovato da Silva
Abstract

The study evaluated the effect of hygiene protocols on physical and mechanical properties and on the microbial load of multispecies biofilm (Candida albicans, Streptococcus mutans and Staphylococcus aureus), as well as wettability and microbial adhesion on 3D-printed resin base and complete denture teeth compared to conventional. The specimens were randomly distributed into groups: EA: Brushing, immersion in water (control); EHS: Brushing, immersion in 0.25% sodium hypochlorite; and ET: brushing, immersion in 0.15% triclosan. The hygiene protocols simulated daily brushing for 6 minutes with neutral soap and daily immersions for 20 minutes for 01 (T1), 03 (T3) and 05 (T5) years. The response variables color, roughness and Knoop microhardness were measured immediately after obtaining the specimens (T0) and after the hygiene period (n=10). Wettability was measured at T0 (n=30). Microbial adhesion and the effect of the protocols (brushing for 40 seconds and immersion for 20 minutes) (n=9) were evaluated through the quantification of Colony Forming Units per mL (CFU/mL), by epifluorescence microscopy and scanning electron microscopy (SEM). Data analysis was performed using Wald-Test in GEE (p&le;0.05), Wald-Test in generalized linear model with multiple comparisons and Bonferroni adjustment (p&le;0.05) and ANOVA test (Two-way), all considering p&le;0.05. The 3D-printed resin showed greater color change than the conventional resin; the printed tooth resin showed greater color change than the base resin. There was no difference between protocols. For 3D-printed, the change was greater in &Delta;T3, &Delta;T5 than in &Delta;T1 (p<0.001). The roughness of the conventional base, in EHS and ET was lower than that of the printed base and conventional tooth; for conventional base in T1, EA caused greater roughness than ET; roughness was greater for T1, T3 and T5 than T0 (p=0.002). The hardness of conventional resins was greater than that of 3D-printed resins; among the 3D-printed resins, the base resin was greater than the tooth resin. EHS and ET caused greater hardness than EA. In T5, hardness was greater than T0, T1, T3 (p<0.001). The conventional resin showed greater wettability than the 3D-printed resin (p<0.001). The adhesion of S. mutans (p=0.023) and S. aureus (p=0.010) was influenced by the resins, being greater on conventional resins. The microbial load of C. albicans was influenced by the protocols (p<0.001), being higher with EA than ET, followed by EHS; the S. mutans count was higher on the base than on the tooth (p=0.043) and in the resin×protocol interaction (p<0.001), EA for conventional resin showed higher counts while EHS and ET promoted biofilm elimination. The S. aureus count was influenced by the resin×application interaction (p=0.001) and by the protocol (p=0.001). Conventional tooth resin had a higher count than base; 3D-printed resin had a higher count than conventional resin; conventional tooth resin showed higher counts than 3D-printed resin; EA caused higher counts than ET. The physical and mechanical properties of 3D-printed resins, especially tooth resins, need to be improved, and ensuring longevity similar to conventional resins. The 3D-printed resins showed lower microbial adhesion and the EHS and ET protocols can be recommended for hygiene of the evaluated resins. (AU)

FAPESP's process: 22/06814-9 - Effect of hygiene protocols on color change, roughness, wettability and hardness, and on the biofilm formed on the surface of 3D-printed teeth resin and 3D-printed base resin of complete dentures.
Grantee:Beatriz de Camargo Poker
Support Opportunities: Scholarships in Brazil - Master