Pathomorphological distinction between Er:YAG and diode lasers on the excisional biopsy of the oral mucosa

Abstract

Background - In oral pathology, laser devices can provide important advantages, especially in the treatment of certain lesions. However, there is controversy about the use of some wavelengths in the analysis of suspected dysplastic or neoplastic lesions, raising doubt about the laser's suitability for use in biopsy procedures. The present pilot study evaluates the pathomorphological characteristics and suitability of Er:YAG and diode lasers for performing excisional biopsies in the oral mucosa with special emphasis on the extent of the thermal damage zone created. Material and Methods - 10 patients were randomly assigned to one diode or one Er:YAG laser groups. The Er:YAG laser(2940nm) was used in a pulsed wave mode 200mJ/35Hz with a power of 7 W. Power settings for the diode laser(810 nm) were 3 W in a pulsed mode. The thermal damage zone of the two lasers and intraoperative and postoperative complications were assessed and compared.All biopsy specimens were evaluated by optical microscopy by threeblinded pathologists. After establishing the pathomorphological diagnosis of the lesion assessed, the pathologists measured the maximal width of the peripheral thermal damage zone in the specimen in μm and classified it using appropriate index. Results - The peripheral thermal damage zone on the borders of the excisional biopsies was significantly smaller with the Er:YAG laser compared to the diode laser regarding values in μm or pathomorphological index scores. No postoperative complications occurred in any of the two groups. Conclusions - The Er:YAG laser seems to be appropriate for excisional biopsies of benign oral mucosal lesions. The Er:YAG laser offers clear advantages in terms of smaller thermal damage zones over the diode laser. Although in some samples thermal damage was minimally visible, in all samples histological evaluation was clearly possible. The study demonstrated that the Er:YAG laser can be safely used in oral biopsy investigations while ensuring a successful histological evaluation, which is fundamental to correct clinical management.