Ultrastructural analysis of bone tissue irradiated by Er : YAG laser

Background and Objectives: The use of erbium:yttrium aluminum garnet (Er:YAG) laser has been suggested for bone ablation, however, little is known about the nature of the tissue after irradiation. This study was aimed to analyze the ultrastructure of bone tissue treated with Er:YAG laser, as compared to those treated with CO2 laser and bur drilling. Study Design/Materials and Methods: Parietal bones of Wistar rats were treated and analyzed by light microscopy, transmission electron microscopy (TEM), electron diffraction analysis and energy dispersive X-ray spectroscopy (SEM-EDX). Results: This study demonstrated that Er:YAG laser irradiation resulted in a very thin changed layer of similar to30 mum thickness, which consisted of two distinct sub-layers: a superficial, greatly altered layer and a deep, less affected layer. Conclusions: The major changes found on bone surface after Er:YAG laser irradiation consisted of micro-cracking, disorganization, and slight recrystallization of the original apatites and reduction of surrounding organic matrix. (C) 2002 Wiley-Liss, Inc.