Zirconia Implants with Laser Surface Treatment: Peri-Implant Bone Response and Enhancement of Osseointegration

Abstract

The aim of this study was to prepare zirconia implants with laser-modified surfaces and to evaluate peri-implant tissue response and osseointegration in an animal study. The experimental zirconia implants received one of the following surface treatments and were placed in the tibiae of SD rats: vertical irradiation with a fiber laser (vertical fiber laser), horizontal irradiation with a fiber laser (horizontal fiber laser), vertical irradiation with a Neodymium-doped yttrium orthovanadate (YVO4) laser (vertical YVO4 laser), and horizontal irradiation with a YVO4 laser (horizontal YVO4 laser). The control implants were smooth surfaced. Tibiae with implant bodies were collected 28 days after implant placement, and removal torque values were measured. Tissue sections were prepared for light microscopy, and the bone-implant contact (BIC) ratio and the peri-implant bone area (BA) were measured. The vertical fiber-laser implants had a mean BIC that was significantly higher than other implants. The mean BIC of the vertical fiber-laser implants was approximately 4.2 folds of the value of the control implants on the cortical bone side and approximately 2.7 folds of the value of the control implants on the bone marrow side. The mean BA was significantly higher in the vertical YVO4-laser implants. The vertical fiber-laser implants had a mean torque removal value that was approximately 2.4 folds of the value of the control implants and approximately double of the value of the vertical or horizontal YVO4-laser implants. The horizontal fiber-laser implants had a mean removal torque value that was approximately double of the value of the control implants and approximately 1.7 folds of the value of the vertical or horizontal YVO4-laser implants (p<0.05). Both types of lasers were useful in implant surface treatment to enhance osseointegration of zirconia implants.

Accelerated Osteogenic Differentiation and Bone Formation on Zirconia with Surface Grooves Created with Fiber Laser Irradiation

“…We investigated how modifying surface topography affects tissues surrounding zirconia implant bodies (ZrI) inserted in a rat tibia. We have previously tested osseointegration after placement of threaded zirconia implants . In the present study, to avoid the effects of the threads on osseointegration and to link the in vivo evaluation to the in vitro results, cylindrical, machined‐surfaced zirconia ceramics without threads were prepared as controls (S‐ZrI) (Figure A).…”

“…The results of our previous in vivo studies showed the stimulating effect of laser irradiation on osseointegration. 26,27 In the present study, by using implant bodies without a thread, we could assess the effectiveness of only the surface topography created by laser irradiation, and compare the in vivo and in vitro results. The results clearly show that surface roughness of implant bodies created by laser irradiation increased the new bone formation.…”

“…We have previously tested osseointegration after placement of threaded zirconia implants. 26,27 In the present study, to avoid the effects of the threads on osseointegration and to link the in vivo evaluation to the in vitro results, cylindrical, machinedsurfaced zirconia ceramics without threads were prepared as controls (S-ZrI) ( Figure 8A). The laser irradiation of S-ZrI produced implant bodies (R-ZrI) with rough surfaces.…”

“…However, this treatment could potentially damage the shape of the implant thread. Instead, we found that a fiber laser can create a rough surface with 2‐μm‐wide grooves and little damage to the nanostructure of the material . Because the interaction between osteoblasts and biomaterials affects cell proliferation and differentiation, suitable modification of the surface topography would be expected to promote successful osseointegration.…”

Surrounding Tissue Response to Surface-Treated Zirconia Implants

“…A few surface modifications to zirconia have been reported for the purpose of improving the bone-tissue response. For example, calcium ion incorporation [17], apatite coating [18,19], ultraviolet irradiation (UV) [20][21][22], sand-blasting [15,23,24], acid-etching [25], and laser treatment [26][27][28][29][30] have been postulated for the effective surface treatment of zirconia. A combination of large-grit sandblasting and acid etching was also reported to be a useful method [15,[31][32][33].…”