Publicação
Study of zirconia antibacterial surfaces for application on dental Implants
| Resumo: | Dental implants are currently the most reliable solution for dental replacement. Although Titanium alloy (TiAl4V) is considered the gold standard dental implant material, some disadvantages have been pointed such as metallic ions release and its greyish colour that can be visible through fine mucosa. Zirconia (ZrO2) is a bioceramic that has been studied as a promising metal-free alternative to titanium due to its good biocompatibility, good mechanical properties compared to other ceramics, good aesthetic, due to its tooth-like colour and low affinity to bacterial microorganisms. Despite the high rate of successful dental implants, problems related to the entry and proliferation of bacteria to the peri-implant zone have been emerging. Peri-implantitis is the most frequent biological cause that leads to implant failure and immediate implant removal. Thus, is extremely important to develop a zirconia surface with antibacterial properties to apply in dental implants. In this context, the present dissertation addresses the study of a barrier approach to inhibit the penetration of microorganisms into the peri-implant zone through the production of successive microgrooves and a biocide approach to eliminate the bacteria that interact with the implant by silver and gold surface chemical functionalization. The microgrooves were produced by an Nd:YAG laser, morphologically characterized by SEM and tested for their retention capacity to artificial soft tissue by mechanical tensile test. Its roughness was also evaluated. The micro-functionalization with silver (Ag) was performed in a two-step process of cold pressing and laser sintering via Nd:YAG laser. And the gold (Au) nano-functionalization was tested by three different methods from which one was selected. Thus, the Au nano-functionalization was carried out by deposition by spray and sintering via CO2 laser. The chemical functionalized samples were subjected to reciprocating friction tests against bone to simulate implant insertion and then analysed through SEM/EDS. The results achieved showed that the introduction of microgrooves on zirconia surface increased the mechanical retention to artificial soft tissue. Roughness evaluation revealed the need for an improvement on laser finishing. The chemical functionalized surfaces presented good resistance to the friction test against bone. Additionally, the obtained COF values can predict good primary stability of the implant. The modified surfaces revealed promising results in the context of the application. |
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| Autores principais: | Barbosa, Alexandrina Machado |
| Assunto: | Zirconia Dental implants Antibacterial Mechanical barrier Microgrooves Biocide effect Gold nanoparticles (AuNP’s) Silver microparticles (Ag) Zircónia Implantes dentários Antibacteriano Barreira mecânica Microrasgos Efeito biocida Nanopartículas de ouro (Au) Micropartículas de prata (Ag) |
| Ano: | 2018 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | português |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Dental implants are currently the most reliable solution for dental replacement. Although Titanium alloy (TiAl4V) is considered the gold standard dental implant material, some disadvantages have been pointed such as metallic ions release and its greyish colour that can be visible through fine mucosa. Zirconia (ZrO2) is a bioceramic that has been studied as a promising metal-free alternative to titanium due to its good biocompatibility, good mechanical properties compared to other ceramics, good aesthetic, due to its tooth-like colour and low affinity to bacterial microorganisms. Despite the high rate of successful dental implants, problems related to the entry and proliferation of bacteria to the peri-implant zone have been emerging. Peri-implantitis is the most frequent biological cause that leads to implant failure and immediate implant removal. Thus, is extremely important to develop a zirconia surface with antibacterial properties to apply in dental implants. In this context, the present dissertation addresses the study of a barrier approach to inhibit the penetration of microorganisms into the peri-implant zone through the production of successive microgrooves and a biocide approach to eliminate the bacteria that interact with the implant by silver and gold surface chemical functionalization. The microgrooves were produced by an Nd:YAG laser, morphologically characterized by SEM and tested for their retention capacity to artificial soft tissue by mechanical tensile test. Its roughness was also evaluated. The micro-functionalization with silver (Ag) was performed in a two-step process of cold pressing and laser sintering via Nd:YAG laser. And the gold (Au) nano-functionalization was tested by three different methods from which one was selected. Thus, the Au nano-functionalization was carried out by deposition by spray and sintering via CO2 laser. The chemical functionalized samples were subjected to reciprocating friction tests against bone to simulate implant insertion and then analysed through SEM/EDS. The results achieved showed that the introduction of microgrooves on zirconia surface increased the mechanical retention to artificial soft tissue. Roughness evaluation revealed the need for an improvement on laser finishing. The chemical functionalized surfaces presented good resistance to the friction test against bone. Additionally, the obtained COF values can predict good primary stability of the implant. The modified surfaces revealed promising results in the context of the application. |
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