Avaliação in vitro dos efeitos do laser de Nd:YAG na aderência de Streptococcus mutans em superfícies radiculares
In vitro study of the adherence of Streptococcus mutans to root surface after Nd:YAG laser irradiation
Vasconcellos, L.M.R.; Fernandes, R.G.; Ito, C.Y.K.; Valera, M.C.; Jorge, A.O.C.
Rev. odontol. UNESP, vol.35, n1, p.1-5, 2006
Resumo
A lesão de cárie radicular pode ser encontrada tanto em pacientes tratados periodontalmente, como em pacientes que não receberam esse tratamento. A presença de Streptococcus mutans pode ser considerada um indicador da atividade de cárie radicular e pode ocorrer com freqüência após raspagem e alisamento radicular. O objetivo deste estudo foi avaliar in vitro a aderência de Streptococcus mutans à superfície radicular de dentes bovinos previamente irradiados com laser Nd:YAG. Vinte e quatro corpos-de-prova foram preparados e divididos em três grupos de acordo com o tratamento recebido: 1) controle - sem tratamento; 2) irradiação com laser de Nd:YAG (200 mJ, 15 Hz e 30 W durante dez segundos); e 3) raspagem e alisamento radicular previamente à irradiação com laser Nd:YAG. Para o teste de aderência, os espécimes foram imersos em caldo infusão de cérebro e coração sacarosado, semeado com Streptococcus mutans GS-5, e mantidos por 24 horas a 37°C. Após o período de incubação, foi realizada a semeadura em ágar infusão de cérebro e coração, e posteriormente foi quantificada a aderência por meio de contagem de unidades formadoras de colônias (UFC). Os dados obtidos foram submetidos ao teste estatístico ANOVA de Kruskal-Wallis e ao teste de Dunn. Os resultados mostraram, no Grupo 2, número significativamente mais elevado de células de S. mutans aderidas e o menor número no Grupo 3. O grupo controle exibiu valores intermediários. Concluiu-se que o uso do laser após a raspagem e o alisamento radicular diminuiu significativamente a aderência in vitro de S. mutans à superfície radicular de dentes bovinos.
Palavras-chave
Laser, Streptococcus mutans, raspagem radicular
Abstract
Root caries may occur among patients submitted or not to periodontal therapy. The presence of Streptococcus mutans may be considered an indicator of root caries activity and it can be frequently isolated after scaling and root planning. The aim of this study was to evaluate in vitro the adherence of Streptococcus mutans to the root surface of bovine teeth after laser Nd:YAG irradiation. Twenty-four specimens were prepared and were divided into three groups according to the treatment: 1) control – no treatment; 2) Nd:YAG laser irradiation (200 mJ, 15 Hz, and 30 W during 10 seconds); and 3) scaling and root planning before Nd:YAG laser irradiation. For the adherence test, all the specimens were immersed in brain heart infusion broth containing sucrose, inoculated with Streptococcus mutans GS-5 and maintained for 24 h at 37°C/5%CO2. After the period of incubation, plating on brain heart infusion agar was performed aiming to quantify the cell adherence through counts of colonies forming units (CFU). Data were submitted by Kruskal-Wallis ANOVA e Dunn’s test. The results showed significantly higher number of Streptococcus mutans cells adhered in group 2 and the lowest number in group 3. Control group showed intermediary value. It was concluded that Nd:YAG laser irradiation after scaling and root planning reduced significantly the in vitro adherence of Streptococcus mutans to the root surface of bovine teeth.
Keywords
Laser, Streptococcus mutans, dental scaling
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