Neusa Silva*1; Mariana da Cruz1; Joana Marques1; Narayan Sahoo2; Óscar Carvalho2; Sara Madeira2; Filipe Silva2; João Caramês3; António Mata4,5

1Oral Biology and Biochemistry Research group - UICOB, Universidade de Lisboa, Faculdade de Medicina Dentária, Lisboa; 2Center for Microelectromechanical Systems (CMEMS), Mechanical Engineering Department, University of Minho, Guimarães; 3Bone Physiology Research Group - Unidade de Investigação em Ciências Orais e Biomédicas (UICOB), LIBPhys-FTC UID/FIS/04559/2013, Universidade de Lisboa, Faculdade de Medicina Dentária; 4CEMDBE - Cochrane Portugal, Universidade de Lisboa; 5Oral Biology and Biochemistry Research Group - Oral and Biomedical Research Unit (UICOB), LIBPhys-FTC UID/FIS/04559/2013, Universidade de Lisboa, Faculdade de Medicina Dentária, Lisboa, Portugal

Background: In recent years, studies in dental implant materials have addressed novel approaches, such us nano and microtexturing to reduce the attachment of microorganism or biofilm formation on dental implants. Nd: YAG Laser based technique has been proposed as potential strategy in the modification of dental implant surfaces, since it allows fast and accurate texture making without direct contact with the implant.

Aim/Hypothesis: The aim of this in vitro study was to evaluate and compare Streptococcus oralis biofilm formation on Hydroxyapatite and Zirconia dental surfaces textured with Nd:YAG laser to produce either micropatterns or sandblasting and acid-etching (SBAE)-like surfaces.

Material and Methods: Yttria Stabilized Zirconia (YTZP) samples were prepared from 3 mol% Yttria-stabilized Tetragonal Zirconia Polycrystal (3Y-TZP) powder using “cold pressing” technique. All Zirconia surfaces were treated with Nd:YAG laser. Hydroxyapatite discs were used as reference. Discs were randomly distributed into three groups according to test group variables and for groups B and C processed using Nd:YAG laser with adapted parameters: Hydroxyapatite (Group A), micropillar patterns (Group B) and SBAE-like surface(Group C ). Streptococcus oralis CECT 907T strain were seeded on the discs at exponential phase and cultured at 37°C in anaerobic condition. Viability and biomass was determined after 1 hour and 24 hours of culture. Bacterial adhesion was observed after 1 hour culture with DAPI, using Confocal Laser Scanning Microscopy (CLSM). Appropriate statistical software was used to perform the analyses and the significance was set at P <0.05.

Results: All tested surfaces revealed an increase in bacterial viability from 1h to 24h of culture, without statistically significant differences between them. No statistically significant differences were detected for bacterial proliferation between all study groups. Biomass increased over time for all groups, with higher values for Group C when compared with Group B at 1h of culture (P < 0.05) but not at 24h in culture.

Conclusion and Clinical implications: Micropillar patterns produced by Nd: YAG laser in zirconia surfaces were less favorable to early bacterial adhesion and biofilm formation when compared to SBAE-like textures produced by laser.

Disclosure of Interest: None Declared.

Keywords: implant surface, surface modification, zirconia