ABSTRACT
Objective @# To investigate the effect of a laser-etched pure titanium surface on proliferation of the human osteosarcoma cell line MG63 and to provide a basis for study of implant surface modification. @*Methods@#The pure titanium plate was cut into titanium pieces by a numerical control machine tool and divided into smooth surface and laser etching groups. The titanium surface of the laser etching group was etched with an Nd:YAG continuous wave laser using predetermined parameters, and the surfaces were observed by scanning electron microscopy (SEM). The surface micromorphology of each titanium sheet was evaluated. The relative element content of the titanium surface was measured by energy dispersive X-ray spectroscopy (EDS). The Ra value of each surface was determined using the Veeco roughness tester. MG63 cells were inoculated on 2 sets of titanium tablets. At 1, 3, and 6 h postinoculation, cell adhesion to the two groups of titanium sheets was observed under the microscope. At 24 h after inoculation, cellular F-actin was directly stained using immunofluorescence, and the morphology of the cytoskeleton was observed by laser confocal microscopy. Cell proliferation was examined at 1, 3, and 5 d using a MTS kit, and the data were analyzed with SAS 9.4.@* Results @#The surface of the smooth surface group was smooth and flat, the element composition was pure titanium, and the roughness Ra was 179.23 nm. The surface of the laser-etched group formed a regular and uniform pore structure. The composition was mainly Ti, O, C, etc, and the surface roughness Ra was 14.11 μm. A large number of cells were uniformly distributed on the two titanium sheets in the observations at 1, 3, and 6 h. At 24 h postinoculation, MG63 cells were completely stretched on the two sets of titanium sheets and had extended a large number of pseudopods and microfilaments to cross-link with peripheral cells; moreover, the cell division phase was observed. The cell proliferation of the two groups at 1, 3, and 5 d showed a significant increase with time, indicating that no cytotoxicity occurred on the surfaces of the two groups. However, the cell proliferation in the laser-etched group was superior to that in the mechanical smooth surface group.@*Conclusion@#The surface morphology of titanium can be controlled by laser etching, which is conductive to increase the microstructure of implants without cytotoxicity and promoting osteoblast proliferation in the early stage.
ABSTRACT
The most common clinical failure in metal ceramic restoration is at the ceramo-metal interface. For the clinical longevity, metal-ceramic prostheses must have satisfactory bond strength between metal and ceramic. Aim and Objective: The aim of this study is to evaluate the effect of Laser etching on shear bond strength between base metal alloys and ceramic. Materials and Methods: A total of 60 specimens were made (Base 5 mm diameter and 1 mm thickness, step with 4 mm diameter and 4 mm in length). They were divided into three groups. Group A-control, Group B-sand blasting, and Group C-laser etching. The Surface morphology, surface roughness, and wettability of the specimens were observed under scanning electron microscope (SEM) Ceramic application was carried out layer by layer for an optimal height of 4 mm. The shear bond strength test was performed using a universal testing machine and the nature of the fracture was examined under SEM. Results: The mean shear bond strength values for laser etched (Group C) Nickel-chromium (Ni-Cr) alloy bonded with ceramic was (49.12 ± 7.12 MPa) and ceramic bonded with Cobalt-chromium (Co-Cr) was (50.04 ± 4.27 MPa), sand blasted (Group B) Ni-Cr alloy bonded with ceramic was (26.00 ± 5.22 MPa), and ceramic bonded with Co-Cr was 24.54 ± 4.78 MPa. The SEM image after debonding showed 10% of adhesive failure and 70% cohesive failure and 20% of both adhesive and cohesive failure for Laser etching. However, there was no significant difference in the values of shear bond strength between the two base metal alloys in Group C. Conclusion: The s hear bond strength between ceramic bonded with Ni-Cr alloys using the Laser etching as surface treatment was 49.12 ± 7.12 MPa and for Co-Cr alloys 50.04 ± 4.27 MPa. Laser surface treatment produces an excellent surface roughness and achieved good shear bond strength values and aid in achieving a better bond strength between metals and ceramic.