Abstract
The aim of this study was to evaluate bone and gingival connective tissue responses towards nanosecond-pulsed laser-treated titanium implants. A Nd:YVO4 nanosecond-pulse laser with a defocus technique was used to modify the surfaces of two types of cylindrical titanium implants. One had a 3.5 mm diameter and 7.0 mm length (∅3.5 Ti) to assess rabbit bone responses; the other a 1.0 mm diameter and 4.5 mm length (∅1.0 Ti) to assess rat gingival connective tissue responses. Laser-treated titanium implants, a ∅3.5 Laser-Ti and ∅1.0 Laser-Ti, were obtained by defocus irradiation. Collagen immobilized ∅1.0Laser-Ti (∅1.0 Coll/Laser-Ti) implants were obtained by a tresyl chloride-activated method. Laser-Ti surfaces had micro-scale roughened oxide layers and parallel arranged grooves. Sa (average roughness) and Sdr (interfacial area ratio) values of the Laser-Ti were significantly higher than those of Ti (titanium) implants (p<0.05). The ∅3.5 implants were implanted into the bone defects of rabbits to evaluate bone responses and ∅1.0 implants were implanted into the extracted sockets of rat maxilla to evaluate gingival connective tissue responses. After implantation periods, the specimens were excised and non-decalcified thin sections prepared to evaluate histological responses. After 12 weeks of implantation in the rabbit experiments, bone-to-implant contact for the Laser-Ti implants was significantly higher than for the Ti in both tibia and femoral condyle (p<0.05). Improved attachment of gingival connective tissue to the implant surface was observed for Laser-Ti and Coll/Laser-Ti in the rat maxilla. Polarized light microscopy showed perpendicular rod-like attachments of gingival collagen fibers on the Laser-Ti and Coll/Laser-Ti implant surfaces. Ti implants had no discernible attachments with gingival connective tissue along the implant surface. In conclusion, nanosecond-pulsed laser treatment with a defocus technique produced roughened titanium surfaces with parallel grooves and micro-roughened asperities. Laser treatment of implants resulted in improved bone responses and attachment of gingival connective tissue.
