Atuação do laser de baixa potência na carcinogênese oral : estudo experimental em ratos

• Autor(a) principal: Lemos, Caroline Farias
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: https://ri.ufs.br/handle/riufs/5886
• topic: Odontologia; Câncer; Tumores odontogênicos; Boca - Tumores; Dentes - Tumores; Inflamação; Lasers em odontologia; Tratamento dentário; Odontologia; Oncologia; Carcinoma; Inflamação; Laser; Inflammation; CIENCIAS DA SAUDE::ODONTOLOGIA

Chronic inflammation has been associated with various stages of carcinogenesis, which have hitherto been studied with the aid of animal models. Low-power laser has also been investigated for its anti-inflammatory and proliferative potential. In order to establish a correlation between the intensity of inflammatory infiltrate and cellular changes taking place during those stages as well as the anti-inflammatory and proliferative potential of laser therapy in tumor induction and progression 48 rats were divided into 8 groups, namely, 4 control groups and 4 experimental groups. Six rats in each group were administered carcinogen 4NQO on the tongue during 12 and 16 weeks, in combination - or not - with laser therapy. After euthanasia, their tongues were removed, examined macroscopically and prepared for histomorphological study with hematoxylin and eosin (HE) stain. As a result, clinically visible lesions were only observed in groups G6 and G7. Nevertheless, from a histological standpoint, Oral Squamous Cell Carcinomas (OSCCs) were observed after 16 weeks of induction in 66.66% of group G4, which had received no laser application. In group G5, where laser therapy was used after 4NQO had been discontinued, the lesions remained as dysplasias, 33.33% of which were moderate (MD) and 66.66% Severe (SD). After 20 weeks of induction all cases exhibited OSCCs and laser therapy contributed to the formation of hyperplastic lesions. Inflammatory infiltrate intensity, however, which was necessary to trigger the carcinogenic process, was not related to the amount or type of cell changes found, nor was it linked to the laser therapy, when compared with the control groups. Thus, the absence of malignant lesions in group G5 shows that laser therapy effectively inhibits the advancement of early-stage carcinogenesis, provided that the risk factor is eliminated. Furthermore, laser therapy was also efficacious in further activating the proliferative potential of already-installed OSCCs, but can not be held responsible for the aggressivity of it.