Morphological Alterations of Periodontal Pocket Epithelium Following Nd:YAG Laser Irradiation

Objective: The purpose of this in vivo study was to examine morphologic alterations in the periodontal pocket epithelium with presence or absence of clinical inflammation following the use of the Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG) laser irradiation. Background data: Subgingival Nd:YAG laser irradiation has been proposed as an alternative technique for treatment of chronic periodontitis. Several published studies have reported the clinical outcomes of such treatment. Methods: Twenty patients, diagnosed with moderate chronic periodontitis, were selected for the study. A total of 32 sites was identified and divided into a control (n=18) and laser-treated test groups (n=14). Probing depth (PD) and bleeding on probing (BOP) were recorded for all sites. Test sites were irradiated with an Nd:YAG laser using parameters of 2 W, 200 mJ pulse energy, and 10 pps delivered through a 320 mu m diameter tip. Total laser treatment time ranged from 1 to 2 min. Following treatment, all specimens were harvested via biopsy and processed for scanning electron microscopy (SEM) and histologic examination. Results: Control group specimens, depending upon initial PD, exhibited either a relatively smooth and intact epithelium with little desquamation (PD <= 3 mm), or increasing degrees of epithelial desquamation and leukocytic infiltration at a PD of >= 4 mm. In the laser-treated test group, the specimens with PD <= 3 mm that were BOP negative (-) exhibited a thin layer of epithelium that was disrupted. In the specimens with initial PD of >= 4 mm, complete removal of the epithelium whose extent and degree were increasing, was observed in the inflamed portion, while epithelium remained in the uninflamed portion. Conclusions: The SEM and histologic findings demonstrated the feasibility of ablating pocket epithelium with an Nd:YAG laser irradiation using parameters of 2 W of power (200 mJ, 10 pps). Furthermore, the presence or absence of clinical inflammation appeared to have an impact on the degree of laser-mediated epithelial ablation.