Introduction: The changes in the regions of the mandibular condyles may be related with fractures, ankylosis and disease. The aim of this study is to present information about Direct Metal Laser Sintering (DMLS) process and its application in manufacture using prostheses of mandibular customized condyles coated with sub microstructured zirconia which has as a result an improvement of the mechanical properties. These areas are submitted to biomechanical efforts of high intensity of chewing forces and these prostheses must have high resistance to fracture.
Materials and Methods: The (DMLS) processes consist in printing prostheses of mandibular customized condyle in 3D techniques with titanium powder. It is necessary acquisition of tomographic images (CONE BEAM) and use InVesallius program and to model the bone defect is performed the reconstruction of 3D virtual images of condyle following mandibular symmetry when one of the mandibular condyles are in normal conditions or when required the reconstruction of images from the both sides. These images are used for the manufacture of customized condyle prostheses and titanium alloy used in this process is Ti-6Al-4V powder. The process of prostheses manufacture is to enter the equipment with titanium alloy powder and distribute this well in layers that are laser synthesized. The bioceramics of sub microstructured zirconia yttria submitted to the milling process and present in its microstructure smaller particles (0,3μm) and results in an increase of their mechanical properties. The equipment used in these processes were EOSINT M270 (EOS), Milling balls, uniaxial pressing, Material Testing System (MTS), Scanning Electron Microscope (SEM).
Results and Discussion: The (DMLS) process result an adequate application and showed hardness of 3,85GPa, tensile strength of 1172MPa, yield strength of 957MPa, modulus of elasticity of 108GPa and stretching 11,0% compared to conventional processes showed hardness of 3,14GPa, tensile strength of 1038MPa, yield strength of 953Mpa, modulus of elasticity of 106GPa and stretching 13,9%. The bioceramics of sub microstructured zirconia yttria result an improvement of the mechanical properties showed hardness of 11,86GP, fracture toughness of 6,89MPa m¹/², Diametrical Compression of 294,57Mpa compared to alumina showed hardness of 16,07GPa, fracture toughness of 5,51MPa m¹/², Diametrical Compression of 100,32Mpa.
Conclusion: The Direct Metal Laser Sintering for application in manufacture using prostheses of mandibular customized condyles coated with sub microstructured zirconia showed adequate results and the adaptation to original anatomical regions is very important to restore functional, physiological and aesthetic like original structures to the patient`s health but is very important the correct indication by surgical team and their surgical skills.
Professora Dra Angela Maria Moraes
References:
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