"Terapia endodôntica associada à irradiação do canal radicular com laser de diodo: avaliação térmica, morfológica, microbiológica e da infiltração marginal apical" / Endodontic root canal therapy usindg diode laser irradiation: thermographic, morphological, microbiological and marginal apical leakge studies

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The aim of this study was to evaluate the effects of diode laser irradiation associated with endodontic therapy. The aspects analyzed were: temperature rise at the external root surface, morphological changes at the dentine root walls, apical marginal leakage after root sealing, and microbiological reduction after laser irradiation. The temperature rise in inferior incisor teeth was monitored using a thermographic camera. Two laser treatment parameters were investigated: continuous emission mode (CW) with P = 2.5 W and pulsed emission mode (PL) with average power?P = 1.25 W. The morphological changes of irradiated samples were analyzed by SEM for both treatment modes and compared with a non-irradiated control group. The apical marginal leakage was measured after the immersion in methylene blue solution for irradiated (CW; P = 2.5 W) and non-irradiated samples sealed by one of the following endodontic sealers: N-Rickert, AH Plus or Apexit. The reduction in microbiological activity after conventional endodontic therapy and after laser irradiation was evaluated in primary endodontic infection using culture and PCR techniques, where the control group used conventional 0.5 % NaOCl solution and calcium hydroxide treatment was compared with laser irradiation (CW; P = 2.5 W). The reduction of viable anaerobic microorganisms, the quantity of E. faecalis and Lactobacillus per samples, and the rate of E. faecalis and Lactobacillus per viable microorganism were analyzed. The temperature rise at external root surface during root canal irradiation in both continuous and pulsed emission modes was demonstrated not exceed the safety limit of 10 ºC. The maximum median temperature variation was 8.6 °C (CW) at the continuous emission mode and 1.6 °C at pulsed mode (PL) (Wilcoxon, p <0.05). The optimal ?resting time? between each of five irradiation cycles was 12 determined to be 20 seconds to allow for tissue cooling and hence to prevent potential dangerous rises in the tissue temperature. SEM analysis revealed melting of dentine and closure of dentinal tubules especially at apical third for both irradiation conditions. The apical marginal leakage was significant reduced in the irradiated samples sealed with Apexit (Kruskal Wallis, p <0.05). The prevalence of the viable anaerobic microorganisms exhibited reduced with time in both the control and laser groups with no statistical difference (Mann-Whitney p >0.05). The Lactobacillus rate per viable microorganisms in the control group was 22 % at the beginning of the treatment and decreasing to zero at the end. This microorganism was not detected in laser group. The rate of Enterococcus per viable microorganism ranged 36 % to 50 % in the control group and 22 % to 0 % in laser group at the begin and the end of treatments, respectively. The conclusion is that diode laser technology is suitable for applications in endodontic therapy under the conditions tested in this study, however, the biological effects are similar to well done conventional endodontic therapy.

ASSUNTO(S)

clinical trial diode laser e. faecalis e. faecalis lactobacillus aumento de temperatura primary infection apical leakage temperature rise redução microbiana infiltração marginal apical infecção primária lactobacillus bacterial reduction estudo clínico laser de diodo

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