Zirconia Implant with Rough Surface Produced by YAG Laser Treatment: Evaluation of Histomorphology and Strength of Osseointegration

Abstract

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.

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 rats were given inhalation anesthesia with isoflurane (Abbott Japan, Tokyo, Japan). Surgical procedures are described in detail in a previous report . Each rat received S‐ZrI in one tibia and R‐ZrI in the other tibia.…”

“…Previously, we succeeded in producing surface roughness by laser irradiation. Microscopic evaluation revealed that irradiation with an yttrium‐aluminum‐garnet laser greatly improved osseointegration and strengthened the attachment indices between bone and zirconia ceramics in addition to increasing removal torque values . However, this treatment could potentially damage the shape of the implant thread.…”

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

“…Therefore, we have conducted previous studies to examine the zirconia-bone interface. In our studies, zirconia implants with modified surface topography were prepared and placed in rat tibiae 27) . Light microscopic observations were made on the healing process of implant-bone interface until osseointegration was achieved.…”

Ca-P spots modified zirconia by liquid precursor infiltration and the effect on osteoblast-like cell responses

“…There are many studies regarding zirconia surface modifications to enhance osseointegration, involving machining 13) , sandblasting 14,15) , laser treatment 16) , plasma spraying 17) , sol-gel 18) and surface bioactive coatings [19][20][21] . However, surface modification of zirconia ceramics is technically difficult 22) due to its high hardness.…”