The aims of this study were to produce rough surfaces on zirconia by laser treatment and to examine how changes in surface topography affect tissues surrounding zirconia implants. Threaded zirconia implants with a diameter of 2 mm and length of 7 mm were used. The experimental implants had surfaces treated with laser (YAG laser) irradiation (R-ZIs). The controls were not treated with laser irradiation (S-ZrIs). Twenty R-ZIs and twenty S-ZrIs were placed in the tibiae of 8-week-old male SD rats. The peri-implant tissues with implant bodies were collected 4 weeks after implant placement. Light microscopic and histomorphological evaluations were performed, and removal torque (RTQ) was measured. The bone-implant contact (BIC) ratio was approximately 1.25 times higher for R-ZrI than for S-ZrI on the side of the cortical bone, indicating a statistically significant difference (p<0.05). There was no statistically significant difference in their BIC ratios on the side of the bone marrow. On the cortical bone side and bone marrow side, there was no statistically significant difference between R-ZrI and S-ZrI in the peri-implant bone area (BA), the area of peri-implant bone within the implant threads. RTQ was approximately 7 times higher for R-ZrIs than for S-ZrIs, indicating a statistically significant difference (p<0.05). In this study, the results of the animal experiment revealed new bone formation in the surroundings of the zirconia implants at 4 weeks after implant placement, indicating achievement of osseointegration. The results suggest that laser-produced rough implant surfaces effectively enhance osseointegration.

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.