Osseointegration of titanium metal implants in erbium-YAG laser-prepared bone

Titanium screws were implanted in rat calvarial defects of identical size using either a laser or bur. The aims of this study were to determine whether the screws were able to osseointegrate in a laser-prepared bone defect and to compare the pattern of bone healing around these screws. The optimal laser settings to produce a 0.7-mm-diameter hole in the rat calvaria were determined. A 0.7-mm-diameter hole was prepared on the left calvaria with the erbium-YAG laser to receive a 1-mm-diameter self-threading titanium screw. Each animal also received a 0.7-mm-diameter hole prepared on the right calvaria with a conventional metal bur, and a 1-mm-diameter self-threading screw implant was placed. Rats were killed humanely either 3 weeks or 3 months after surgery, and the skulls were processed in paraffin wax for histological analysis. Laser-prepared defects: At 3 weeks, the screw was surrounded by vital woven bone. The dura mater was perforated, and cystic change was present in the underlying brain tissue. There was active bone formation adjacent to the screw surface, deposited on a thin zone of necrotic bone. At 3 months, the screws were osseointegrated, and the brain tissue was healed by gliosis. Bur-prepared defects: At 3 weeks, there was extensive remodeling around the prepared defect. The dura mater was intact, and there was no damage to the underlying brain. At 3 months, the screws were successfully osseointegrated with bone adjacent to the screw. Osseointegration of titanium screws can be achieved using an erbium-YAG laser to prepare the implant bed.