Efeito in vitro da laserterapia e da terapia fotodinâmica na redução de bactérias presentes em canais radiculares / In vitro effect of lasertherapy and photodynamic therapy in bacterial reduction presents in root canals

Este estudo tem por objetivo verificar in vitro o efeito bactericida da laserterapia e da terapia fotodinâmica com laser de baixa potência (660 nm e 808 nm) em bactérias presentes nos canais radiculares. Métodos: foram preparadas 60 placas de Petri com bactérias: 20 placas com Enterococcus faecalis, 20 placas com Staphylococcus aureus e 20 com Pseudomonas aeruginosa. Aleatoriamente, dividiu-se cada grupo em 10 subgrupos (duas placas cada): três subgrupos tratados com laserterapia 660 nm em doses de 150, 225 e 300J/ cm², três subgrupos tratados com terapia fotodinâmica (azul de metileno 0,2% e laser 660 nm) em doses de 150, 225 e 300J/cm²; um subgrupo tratado com laserterapia 808 nm na dose de 225J/cm², um subgrupo com terapia fotodinâmica e laser 808 nm, em dose 225J/cm²; um subgrupo tratado apenas com fotossensibilizante (FS), e um não tratado (controle). Os tratados com laserterapia e terapia fotodinâmica foram irradiados uma única vez e incubados por 24 horas. Os últimos dois não receberam irradiação. As culturas foram analisadas visualmente para verificação do halo de inibição. Nos grupos submetidos somente à laserterapia, para o grupo FS e para o grupo controle, não foram observados halos de inibição, já onde houve aplicação da TFD, tanto com L1 quanto com L2, observaram-se halos de inibição em todas as espécies bacterianas estudadas. Conclui-se que a laserterapia, não produziu efeitos bactericidas e/ou bacteriostáticos, enquanto a terapia fotodinâmica nos dois comprimentos de onda produziu halos significativos de inibição de crescimento nas três bactérias do estudo.(AU)

This study aims to verify in vitro the bactericidal effect of laser therapy and photodynamic therapy with low power laser (660 nm and 808 nm), in bacteria present in the root canals.Methods: 60 Petri dishes were prepared with bacteria: 20 plates with Enterococcus faecalis, 20 plates with Staphylococcus aureus and 20 with Pseudomonas aeruginosa. At random, each group was divided into 10 subgroups (two plates each): three subgroups treated with 660nm laser therapy at doses of 150, 225 and 300J / cm², three subgroups treated with photodynamic therapy, (0.2% methylene blue and laser 660nm) in doses of 150, 225 and 300J / cm²; a subgroup treated with 808nm laser therapy at a dose of 225J / cm², a subgroup with (photodynamic therapy and 808nm laser) at a dose of 225J / cm²; a subgroup treated only with photosensitizer(FS), and an untreated (control). Those treated with laser therapy and photodynamic therapy were irradiated only once and incubated for 24 hours. The last two received no radiation. The cultures were analyzed visually to check the inhibition zone. In the groups submitted to laser therapy only, for the FS group and for the Control group, no inhibition halos were observed, since PDT was applied, with both L1 and L2, inhibition halos were observed in all studied bacterial species. It was concluded that laser therapy did not produce bactericidal and / or bacteriostatic effects, while photodynamic therapy at both wavelengths produced significant growth inhibition halos in the three studied bacteria.(AU)

Microbiological analysis of absorbent paper points employed by undergraduate students from a dental school in south of Brazil

Aim: The aim of this study was identify contamination on absorbent paper points used by students of Dental Clinic III of the Faculty of Dentistry of Federal University of Rio Grande do Sul in the semester 2015/1, in order to warn students and professionals of the area on the importance to sterilize these materials. Material and Methods: In a clinical environment, 180 absorbent paper points we collected (80 of them from the first series and 80 from the second one), from 40 students. After the collection, each one was singly immersed in a microtube containing 1.5 ml of the BHI (Brain Heart Infusion) culture. Positive control was composed by one paper point contaminated by saliva, and negative control was composed by a closed microtube, only with BHI. The microtubes were incubated at 37ºC in bacteriological incubator during 14 days. The microtubes that presented turbidity were considered positive, and those which did not present turbidity were considered negative. Results: The results were analyzed by the Fisher Exact Test, which demonstrated that paper points from the second series presented higher agreement contamination between the paper points collected from each box, when compared to the analyzed boxes from the first series (p=0.03). All the samples observed presented growth of Bacillus spp in the microorganism identification. Conclusions: It is possible conclude that absorbing paper points, when exposed to clinical environment suffer contamination, and the autoclave sterilization is necessary before the use, regardless the commercial brand, in order to ensure the aseptic chain maintenance.

Influência da conicidade dos instrumentos rotatórios de NiTi no transporte apical û um estudo comparativo com tomografia computadorizada / Influence of taper of NiTi rotary instruments in apical transportation: a comparative study with computed tomography

A proposta deste estudo foi avaliar, ex vivo, a influência da conicidade dos instrumentos rotatórios de níquel-titânio (NiTi) no transporte apical de canais radiculares curvos com tomografia computadorizada. Vinte primeiros molares superiores humanos extraídos foram selecionados e divididos em dois grupos. Os canais radiculares no GrupoHERO 642 (n=10) foram preparados com instrumentos rotatórios de NiTi do sistema HERO 642, conicidade 0,02. Os canais radiculares do Grupo EASY ProDesign (n=10) foram preparados com instrumentos rotatórios de NiTi EASY ProDesign, conicidades múltiplas. O transporte apical foi mensurado comparando imagens de tomografia computadorizada antes do preparo, após o preparo com instrumentos # 35/.02 (Grupo HERO 642) e instrumento # 35/.04 (Grupo EASY ProDesign), e após o preparo com instrumento # 45/.02 (Grupo HERO 642) e instrumento # 40/.04 (Grupo EASY ProDesign). Os dados foram analisados utilizando ANOVA e o nível de significância p. 05. Os valores médios de transporte apical em milímetros (mm) para o Grupo HERO 642 foram 0,93 ± 0,48 mm (#35/.02) e 1,48 ± 0,63 mm (# 45/.02) e para o Grupo EASY ProDesign foram 0,82 ± 0,85 mm (# 35/.04) e 1,03 ± 0,92 mm (# 40/.04). Os instrumentos rotatórios de NiTi de conicidade 0,02 e de múltiplas conicidades mostraram desempenho similar em relação ao transporte apical em canais radiculares curvos.

The aim of this study was to evaluate ex vivo the influence of the taper of nickel-titanium (NiTi) rotary instruments in apical transportation of curved root canals with computed tomography. Twenty extracted maxillary first molars were selected and divided into two groups. The mesiobuccal root canals in Group HERO 642 (n=10) were instrumented with HERO 642 rotary instruments, 0.02 taper. The mesiobuccal root canals in Group EASY ProDesing (n=10) were instrumented with EASY ProDesign rotary instruments, multiple tapers. Apical transportation was measured by comparing tomographic images before preparation, after the preparation with size 35, 0.02 taper (Group HERO 642) and size 35, 0.04 taper (Group EASY ProDesing), after the preparation with size 45, 0.02 taper (Group HERO 642) and size 40, 0.04 (Group EASY ProDesing). Data were analyzed using ANOVA, and significance was set at p.05. The preparation of curved root canals can be accomplished with instruments of diameters and taper larger than 0.02.

Efficacy of passive ultrasonic irrigation in removing root filling material during endodontic retreatment / Eficácia da irrigação ultrassônica passiva na remoção de material obturador durante o retratamento endodôntico

Introduction: The aim of endodontic retreatment is to remove the previous root filling materials completely to allow for the subsequent steps of cleaning, canal shaping and filling replacement. Objective: To evaluate the efficacy of passive ultrasonic irrigation (PUI) in the removal of residual root filling material after removing the bulk of the root filling with nickel-titanium rotary instruments. Material and method: Eighteen mesial isthmus-containing roots of human mandibular molars were prepared and filled. The root canal filling was removed with the ProTaper Retreatment system and K-files. The specimens were randomized into 2 groups (n = 9), both irrigated with 2.5% NaOCl and 17% EDTA. In the conventional group, an irrigation syringe was used. In the PUI group, the PUI technique was used. The roots were sectioned longitudinally and evaluated under stereomicroscopy. Student's t test was used to compare groups and the general linear model was used to compare the apical, cervical, and middle root thirds within each group, in regard to the percentages of remaining residual filling material. Result: There was no statistically significant intergroup difference, irrespective of which root third was evaluated (P > 0.05). In the PUI group, the apical third showed a significantly higher percentage of residual filling material, in comparison with the cervical (P = 0.038) and middle (P = 0.029) thirds. Conclusion The PUI technique was not more effective than the conventional irrigation technique in removing residual root filling material during endodontic retreatment in root canals with a complex anatomy.

Introdução: O retratamento endodôntico requer a remoção de todos os materiais obturadores para a limpeza, o preparo e a obturação subsequentes do canal radicular. Objetivo: Avaliar a eficácia da Irrigação Ultrassônica Passiva (IUP) na remoção de material obturador residual após a desobturação com sistema rotatório de níquel-titânio. Material e método: Dezoito raízes mesiais de molar inferior com istmos foram preparadas e obturadas. A obturação foi removida com o sistema rotatório ProTaper Retratamento e limas manuais tipo K. Os espécimes foram randomizados em dois grupos (n = 9), ambos irrigados com NaOCl a 2,5% e EDTA a 17%. No grupo Convencional, a seringa de irrigação foi utilizada. No grupo da IUP, a técnica da IUP foi usada. As raízes foram seccionadas longitudinalmente e avaliadas em estereomicroscópio. O teste t de Student foi usado para comparar os grupos e o modelo linear geral foi usado para comparar os terços cervical, médio e apical dentro de cada grupo, no que diz respeito a porcentagem de material obturador residual. Resultado: Não houve diferença estatisticamente significante entre os grupos, independentemente do terço do canal radicular analisado (P> 0.05). No grupo da IUP, o terço apical mostrou uma porcentagem significativamente mais alta de material obturador residual quando comparado aos terços cervical (P = 0.038) e médio (P= 0.029). Conclusão: A IUP não foi mais eficaz do que a técnica convencional na remoção de material obturador remanescente durante o retratamento endodôntico em canais radiculares com anatomia complexa.

Effectiveness of passive ultrasonic irrigation on calcium hydroxide removal with different solutions / Efetividade da irrigação ultrassônica passiva na remoção de hidróxido de cálcio com diferentes soluções

Objective: this study aimed to assess the effectiveness of Passive Ultrasonic Irrigation (PUI) with different so-lutions for calcium hydroxide (Ca(OH)2) removal. Ma-terials and method: forty-eight single-rooted mandibu-lar premolars were prepared and filled with Ca(OH)2. After 15 days, the specimens were randomly divided into four groups according to the method of removal of the intracanal medication (n=12). In Group 1, Ca(OH)2removal was performed through conventional irrigation with 2.5% NaOCl and 17% EDTA combined with the use of the 'master apical file' at working length. Groups 2 and 3 were treated in the same manner as Group 1, following the PUI with 2.5% NaOCl and 17% EDTA, and 2.5% NaOCl and 10% citric acid, respectively. Group 4 served as a control group and received no intracanal medication. The roots were longitudinally grooved and split in two halves. The half with the higher remaining amount was analyzed with a stereomicros-cope, and the percentage of surface area covered by the remaining Ca(OH)2 in relation to the total surface area and the surface area of each third of the root canal was calculated. The results were statistically analyzed with the Kruskal-Wallis Test and Mann-Whitney Test. Null hypothesis was set as 5%. Results: none of the groups tested showed similarity to the control group (P < 0.05)...