ULTRASTRUCTURAL CHANGES OF THE MOUSE PERIODONTIUM AFTER HeNe LASER RADIATION:

Abstract

Helium-neon (HeNe) laser radiation is usually utilized in dentistry for diagnostic and therapeutic purposes, principally in Europe. No studies on the ultrastructural effects of HeNe laser irradiation of the periodontal tissues have been reported. This study shows the ultrastructural effects of HeNe laser radiation in mouse periodontium in two different conditions of irradiation. Twenty-four forty days old albino mice were irradiated with a HeNe laser source. They were divided into two groups according to dosage and time (two and six minutes of irradiation. 10.50566J/cm2 and 51.51698 J/cm2 respectively . Each group was subdivided depending on the time of animal sacrifice (immediately after irradiation or 10 days later, respectively). A further 12 mice served as controls using the same handling procedures and times as the experimental groups, but without radiation. In transmission electron microscopy (T.E.M.) ultrathin sections showed epithelial alterations only in the group irradiated for six minutes, and was more manifested in the sacrificed animals ten days after the irradiation. In the low dose irradiated animals, the bone showed two osteocyte populations according to their response to radiation. The connective tissue also showed two types of fibroblast population. This study showed abnormal cellular effects after HeNe laser irradiation in healthy rat periodontium, being more predominant at higher doses, although also present at doses usually utilized in clinical practice.