engleski

COMPARATIVE HISTOLOGICAL BONE TISSUE ANALYSIS AFTER LASER AND DRILL OSTEOTOMY

The use of drilling procedures has distinct disadvantages, such as broadening of cuts, extensive heat deposition, mechanical traumatization, deposition of metal shavings and bacterial contamination. Haemostatic and aseptic effects, absence of mechanical stress and intricate cut geometry are potential beneficial aspects of noncontact osteotomy with infrared lasers. The aim of this study was to compare bone tissue effects after osteotomy site or screw holes performed with Er:YAG laser and surgical drill. The study was performed on the 5 pig ribs prepared with saggital osteotomy to get two equal parts of the rib. Each part was separated in equal plates with similar thickness of cortical and spongious bone mutually. The idea was to simulate height and width of intraoral autologous bone blocks commonly used in bone management. On the each plate two osteotomies were performed. For the osteotomies, non-contact Erbium-YAG laser (AT Fidelis, Fotona, Slovenia) was applied with the 0.9mm spot size in the max mode (1000mJ, 20Hz) and the handpiece was kept at a distance of 10mm from the bone surface to make bone site within the full thickness of the plate. The other osteotomy, as a control, was performed with the 1.0mm wide surgical drill (Screw System, Hager&Meisinger GmbH, Germany), commonly used for the fixation screws preparations, at 15 000rpm, with simultaneous saline irrigation. For light microscopic investigation, samples were decalcified in 5% nitric acid solution and processed in paraffin wax. Histological saggital sections through each osteotomy site were prepared and stained with hematoxylin and eosin. Histological evaluation of the laser sites demonstrated an altered layer in the margins of the osteotomy of approximately 30-μm thickness, while drill sites did not present any altered layer. In the case of laser osteotomy, superficially thin affected layer with irregular borders was composed by two different sublayers: a lightly stained superficial layer with no defined structures and a darkly stained underlying layer, presenting minimal thermal damage. Empty osteocyte lacunae could be observed approximately 30μm distant from the irradiated surface. The surface of the bur-performed grooves was covered with a thin smear layer with regular border. No thermal damage was observed. Er:YAG laser irradiation caused only minimal thermal damage to bone ablated at the specified parameters and may become applicable as an alternative method for bone surgery.

oral surgery; dental implantology; bone; laser; histology

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