Effects of an Er:YAG laser and the Vector ultrasonic system on the biocompatibility of titanium implants in cultures of human osteoblast-like cells

Abstract

The aim of the present study was to investigate the effects of an Er:YAG laser (ERL) and the Vector ultrasonic system (VS) on the biocompatibility of titanium implants in cultures of human osteoblast-like cells (SAOS-2). One hundred and sixty-eight titanium discs with four different surfaces (sand-blasted and acid-etched, titanium plasma-sprayed, machine-polished, and hydroxyapatite-coated) were used to evaluate cell attachment. The samples were equally and randomly assigned to the following groups: (1) an ERL at an energy level of 100 mJ/pulse and 10 Hz using a special application tip, (2) the VS using carbon fibre tips, or (3) untreated control (C). The discs were placed in culture plates, covered with a solution of SAOS-2 cells, and incubated for 7 days. The specimens were then washed with phosphate buffer to remove cells not attached to the surface, and the adherent cells were stained with hematoxilin-eosin. Cells were counted using a reflected light microscope and the cell density per mm2 was calculated. Additionally, cell morphology and surface alterations of the titanium discs after treatment were investigated using scanning electron microscopy (SEM). All titanium discs treated with ERL demonstrated nearly the same cell density per mm2 as the untreated C surfaces. There was a significant decrease in the number of cells that attached to the implant surfaces treated with VS. The SEM examination showed no visible differences between lased and C titanium surfaces. All surfaces treated with VS showed conspicuous surface damage and debris of the used carbon fibres. The results of the present study indicate that (i) ERL does not damage titanium surfaces and subsequently does not influence the attachment rate of SAOS-2 cells, and (ii) VS, used with this type of carbon fibre tip, does not seem to be suitable for the instrumentation of titanium surfaces.