The Design Of Customized Root Analogue Implants Based On Laser 3D Printing Technique And Biological Evaluation In Vitro

[Objective] Dental implant is known as human’s third set of teeth and widely used across the globe, based on osseointegration theory presented by Sweden Professor Branemark and the excellent biocompatibility of titanium. People constantly seek to optimize the design of implant structure and surface treatment in order to obtain a more stable combination since the first clinical trial of titanium implant placement on one patient in 1965. But the implant process is too long. Besides, there exists continuous physiological absorption of the alveolar bone after tooth extraction for patients with dental trauma or residual root cannot be reserved. The aim of this study is to design a kind of porous structure on the root analogue implant surface, which not only matches the tooth socket to achieve immediate implantation, but increases roughness and contact area for early osseointegration. In addition, the STL file was directly fabricated through three dimensional printing and rapid prototyping technology. The physicochemical and biological properties of porous surfaces were evaluated in vitro and provide a theoretical basis for later research.[Materials and methods] The Beagle dog was chosen as the animal model and the data of natural teeth was obtained by CBCT scanning. Mimics, Autofab and Magics were used to reconstruct three-dimensional models, design the surface structure and simulate the implantation in the mandible. Titanium alloy implants and plates were obtained by laser 3D printing technology. Porous titanium plate was regarded as the experimental group and non-porous titanium plate for comparison. Surface microstructure, elemental composition and the adsorption capacity of BS A for both groups were tested. Cell adhesion and proliferation were detected by means of the culture of MC3T3-E1 on the plate surface.[Results] Porous structures are observed on both the titanium implants and plates surfaces, with the single-hole diameter of about 200μm. The result of protein adsorption suggested that BSA and FBS residual level on experimental group titanium were higher than the control (P<0.001). CCK-8 result showed no significant difference between two groups in cell initial number (P>0.05). Fluorescence microscope observation showed porous surface provided a three-dimensional environment for the adhesion and proliferation of MC3T3-E1, but still not completely covered by cells after one week. However, there was no spare space of the titanium plate surface after 7 days in the control group.[Conclusion] By means of CAD and three dimensional printing technologies, we are able to customize dental implants easily; nevertheless, its precision is influenced by printing equipment, metallic raw material, shape design, etc. Additionally, the platform design of implant and its connection with abutment need to be further studied. Both titanium porous surface and acid etching process contribute to the MC3T3-E1 cell adhesion and proliferation; it is positively correlated with surface area which porous structure provides.