Efficacy of diode laser and sonic agitation of Chlorhexidine and Silver-nanoparticles in infected root canals / Eficácia do laser de diodo e agitação sônica de clorexidina e nanopartículas de prata em canais radiculares infectados

Objective: To assess the efficacy of agitation of chlorohexidine (CHX) and Silver nanoparticles "AgNps" with 810nm diode laser or sonic endoactivator compared to side ­vented needle on infected root canals with Enterococcus "E" Faecalis biofilms. Material and Methods: Sixty-five extracted human premolars with single oval canals were instrumented by protaper system up to F3. Biofilms of E. faecalis were generated based on a previously established protocol. Two teeth were used to check the biofilm formation, then the remaining Teeth were randomly divided into three equal experimental groups according to agitation techniques used: group 1 (810 nm diode laser with 1 watt) , group 2 (sonic endoactivator) and group 3 (Side vented needle). Each group was further divided into three equal subgroups according to the irrigant solution into; subgroup A: chlorohexidine, subgroup B: silver nanoparticles and subgroup C: distilled water: Confocal laser scanning microscopy "CLSM" was used to assess bacterial viability. Data were analyzed by appropriate statistical analyses with P = 0.05. Results: Regarding the activation method, all groups had a significantly high percentage of dead bacteria (P < 0.05). However, Laser was significantly the highest and Endoactivator the least (P < = 0.001). Diode laser agitation of AgNps irrigant showed the highest reduction percentage of bacteria (78.1%) with a significant difference with both CHX and water irrigation, Conclusion: Under the condition of the present study; results reinforced that laser activation is a useful adjunct, 810 nm diode laser agitation of AgNps or chlorhexidine was more effective in disinfection of oval root canals than endoactivator and side vented needle techniques. (AU)

Objetivo: Avaliar a eficácia da agitação de clorohexidina (CHX) e nanopartículas de prata (AgNps) , com laser de diodo de 810 nm ou endoativador sônico, em comparação à agulha de ventilação lateral, em canais radiculares infectados com biofilmes de Enterococcus "E"; Faecalis. Material e Métodos: Sessenta e cinco pré-molares humanos com um único canal oval, extraídos, foram instrumentados pelo sistema protaper até F3. Os biofilmes de E. faecalis foram gerados com base em um protocolo previamente estabelecido. Foram utilizados dois dentes para verificar a formação do biofilme, e os dentes restantes foram divididos aleatoriamente em três grupos experimentais iguais, de acordo com as técnicas de agitação utilizadas: grupo 1 (laser de diodo 810 nm com 1 watt), grupo 2 (endoativador sônico) e grupo 3 (Agulha com ventilação lateral). Cada grupo foi dividido em três subgrupos iguais, de acordo com a solução irrigante; subgrupo A: clorohexidina, subgrupo B: nanopartículas de prata e subgrupo C: água destilada: A microscopia confocal de varredura a laser foi usada para avaliar a viabilidade bacteriana. Os dados foram analisados por análises estatísticas apropriadas com P = 0,05. Resultados: Em relação ao método de ativação, todos osgrupos apresentaram percentual significativamente alto de bactérias mortas (P < 0.05). No entanto, para o laser foi significativamente o mais alto e, para oendoativador, o menos alto (P < = 0.001). A agitação com laser de diodo doirrigante AgNps apresentou a maior porcentagem de redução de bactérias (78,1%), com diferença significativa tanto para irrigação com CHX quanto comágua. Conclusão: Sob as condições do presente estudo; os resultadosreforçaram que a ativação a laser é um complemento útil, a agitação por laserde diodo de 810 nm de AgNps ou clorexidina foi mais eficaz na desinfecção dos canais radiculares ovais do que as técnicas de endoativador e agulha com ventilação lateral. (AU)

Microhardness and Ultrastructure of Demineralized Gamma-Irradiated Human Enamel after Diode Laser (980 nm) and Fluoride Surface Treatment

Abstract Quality of life drastically diminished after radiotherapy due to radiation induced oral complications. Fluoride was found to be helpful in decreasing the incidence of radiation caries; however it has not led to elimination of dental caries. Thus, new techniques containing low fluoride concentration or not containing fluoride at all, as laser irradiation, have been studied to prevent the beginning or progression of caries. So the purpose of this study is to investigate the effect of laser surface treatment with or without fluoride on microhardness and ultrastructure of demineralized gamma irradiated enamel; Thirty enamel slabs were allocated into three groups (n=10): G slabs were subjected to gamma irradiation only; GL slabs were subjected to gamma irradiation followed by diode laser and GFL slabs were subjected to gamma irradiation followed by fluoride then diode laser. Slabs were then exposed to demineralizing solution for 72 hours. Examination of slabs was performed using vickers microhardness test and scanning electron microscope; The lowest microhardness was recorded in group G, while inGL and GFL groups it significantly increased. Scanning electron microscope revealed a pronounced loss of central prism core and retention of prism peripheries in group G. Confluence of prismatic and interprismatic structures in GL slabs and irregular rough surface with prismatic boundaries conservation in GFL slabs were detected. Applying laser improved the microhardness and counteracted the adverse effect of gamma radiation. Adding fluoride before laser irradiation had a marked effect on microhardness..