Extrusão apical de irrigantes em dentes imaturos utilizando diferentes dispositivos de irrigação por pressão negativa / Apical extrusion of irrigants in immature teeth using different negative pressure irrigation devices

Objetivo: O objetivo deste estudo foi avaliar a extrusão apical de irrigantes em dentes imaturos simulados, comparando a irrigação convencional com outros dispositivos de irrigação por pressão negativa. Materiais e Métodos: 48 amostras de dentes imaturos simulados foram montadas em um modelo adaptado para conter o irrigante extravasado e distribuídas igualmente em 4 grupos (n=12) de acordo com o dispositivo de irrigação utilizado: Grupo Irrigação Convencional (IC), Grupo EndoVac (EV), Grupo Pulp Sucker (PS) e Grupo Ivac (IV). As amostras foram irrigadas com 15mL de solução irrigadora, sendo 10mL de NaOCl a 2,5% e 5mL de EDTA a 17% intercalados. As amostras foram pesadas em balança de precisão antes e depois dos procedimentos de irrigação, sendo a diferença entre os pesos final e inicial considerado o volume de irrigante extravasado. Os dados foram coletados e analisados estatisticamente pelos testes de Kruskal-wallis e exato de Fisher. Resultados: Os grupos que utilizaram pressão negativa promoveram significativamente menor volume de irrigante extravasado que o grupo IC (p<0,05), não havendo diferenças significativas quando comparados entre si (p>0,05). Houve diferenças significativas na associação entre os grupos e a extrusão de irrigante, sendo o grupo PS menos associado a extrusão de irrigante (p<0,005). Discussão: Estudos anteriores apontam os dispositivos de pressão negativa como opções seguras diante de extravasamento de irrigantes quando comparados à irrigação convencional. Conclusão: A irrigação convencional promoveu significativamente maior volume de extrusão de irrigante quando comparada aos dispositivos de irrigação por pressão negativa. O sistema PulpSucker mostrou extravasamento de irrigante em um número significativamente menor de amostras.

Aim: The aim of this study was to evaluate the apical extrusion of irrigants in simulated immature teeh, comparing convencional irrigation with other negative pressure irrigation devices. Materials and methods: 48 samples of simulated immature teeth were set up in an adapted model to contain the extravasated irrigant and evenly distributed into 4 groups (n=12) according to the device used: Convencional Irrigation Group (CI), EndoVac Group (EV), Pulp Sucker Group (PS) and Ivac Group (IV). The samples were irrigated with 15mL of irrigant solution, consisting of 10mL NaOCl 2,5% and 5mL EDTA 17%, in na alternating sequence. The samples' weights were measured using a precision scale before and after the irrigation procedures, with the difference between de final and initial weights considered the volume of extravasated irrigant. Data were collected and statistically analyzed by Kruskal-wallis and Fisher exact tests. Results: The groups that used negative pressure devices significantly promoted a lower volume of extruded irrigant than the CI group (p<0,05), with no significant differences between the negative pressure groups (p>0,05). There were signficant differences in the association between the groups and irrigant extrusion, with the PS group showing significantly less association with irrigant extrusion (p<0,005). Discussion: Previous studies have indicated that negative pressure devices are safe alternatives to convencional irrigation when considering irrigant extrusion. Conclusion: Conventional irrigation promoted a significantly greater volume of irrigant extrusion when compared to negative pressure irrigation devices. The PulpSucker system showed irrigant extravasation in significantly fewer samples.

The use of cone beam computed tomography by brazilian endodontists: A questionnaire-based survey.

Background: This study aimed to assess the knowledge of Brazilian endodontists regarding the use of cone beam computed tomography (CBCT) in endodontic therapy. Material and Methods: An invitation to participate in the research was sent to 3256 professionals through class groups on social networks and via email. Participants answered an online questionnaire consisting of 11 questions about the clinical situations in which they used CBCT and whether they had any knowledge of the technical protocols such as parameters of field of view (FOV) and voxels of the CBCT equipment. The questionnaire was answered by 742 endodontists who represented 22.7% of the invited professionals. Results: The data obtained indicate that 76.7% of the participants use or have used CBCT during endodontic treatments. The most often reported clinical conditions for using the CBCT were: root fractures (64%), locating the canals (58.7%), perforations (53.9%), and root resorption (42.1%). More than 60% of the participants stated that they do not have information about the voxel, FOV, and the CBCT system used in their requests. Only 34.1% reported using CBCT to the performed endodontic treatments follow-up. Conclusions: CBCT was a tool widely utilized by the participants, with root fracture being the clinical condition with the highest indication for CBCT. Many professionals were unaware of the technical protocol used in the exams. Key words:Endodontics, Cone Beam Computed Tomography, Endodontic Therapy.

Odontometria eletrônica em dentes decíduos: revisão de literatura e relato de caso / Eletronic working length determination in primary tooth: review of literature and case report

Objetivo: Realizar uma revisão dos principais artigos encontra-dos na literatura acerca do uso dos Localizadores Eletrônicos Foraminais (LEF) em dentes decíduos e representar através de um relato de caso clínico, a importância do uso destes dispositivos durante o tratamento endodôntico em dentes decíduos. Revisão da literatura: Foi realizada uma busca nas principais bases de dados, e selecionados 13 artigos consi-derados mais relevantes. Todos os estudos mostraram que a determinação da odontometria em dentes decíduos utilizando o LEF é bastante segura e com boa acurácia, podendo ser utilizado o localizador para esta finalidade. Relato do caso:No caso clínico apresentado, o uso do LEF foi fundamental para a obtenção de uma odontometria precisa, além da diminuição do tempo de cadeira e identificar reabsorções não detectáveis radiograficamente. O caso foi conduzido em duas sessões, onde na primeira foi realizada a cirurgia de acesso, odontometria eletrônica, preparo manual dos canais e utilização de medicação intracanal de hidróxido de cálcio. Na segunda sessão foi removida a medicação intracanal e os canais foram obturados utilizando pasta iodoformada. Discussão: O uso do LEF no tratamento endodôntico de dentes decíduos tem se mostrado uma ferramenta segura e eficiente, tendo melhor performance na determinação do comprimento de trabalho quando comparado a outros métodos. Conclusão: De acordo com os estudos apresen-tados na revisão de literatura e o caso clínico apresentado, pudemos constatar que o uso do LEF contribui positivamente ao tratamento, principalmente quanto ao ganho de tempo e determinação confiável e segura do comprimento de trabalho.

Aim: To review the main articles found in the literature on the use of Electronic Apex Locators (EAL) in deci-duous teeth, and to represent, through a clinical case report, the importance of using these devices during endodontic treatment in deciduous teeth. Review of literature: A search was performed in the main data-bases, and 13 articles considered most relevant were selected. All studies showed that the determination of odontometry in deciduous teeth using LEF is quite safe and with good accuracy, and the localizer can be used for this purpose. Case report: In the clinical case presented, the use of EAL was fundamental to obtain an accurate odontometry, besides the reduction of chair time and exposure to ionizing radiation. The case was conducted in two sessions, where in the first one the access surgery was performed, electronic odontometry, manual preparation of the canals and use of intracanal medication of calcium hydroxide. In the second session the intracanal medication was removed and the canals were filled using iodoform paste. Discussion: The use of LEF in the endodontic treatment of primary teeth has been shown to be a safe and efficient tool, with better permormance in determining the working length when compared to other methods. Conclusion: According to the studies presented in the literature review and the clinical case presented, we could verify that the use of LEF contributes positively to treatment, especially in terms of time gain and acurate determination of working length.

Retrospective study of endodontic treatment performed by undergraduate students using reciprocating instrumentation and single-cone obturation.

OBJECTIVES: The aim of this cross-sectional retrospective study was to evaluate radiographically the technical quality of root canal treatment performed by undergraduate students using reciprocating NiTi instrumentation and single-cone obturation. METHODS: Endodontic treatment on 1102 teeth performed by undergraduate students from the School of Dentistry of the University of Santa Cecilia (Brazil) was evaluated. All root canal preparations were performed using Reciproc files and were irrigated with 1% NaOCl. The root canal was filled with gutta-percha, along with AH Plus sealer, using the single-cone obturation technique. The technical quality of the root canal treatment was evaluated based on immediate postoperative radiographs. Distance between the end of the filling and the radiographic apex, the filling density, and the taper of the root filling was assessed. Inter-examiner agreement statistic (Kappa) and Chi-square statistic test were used for statistical evaluation of the results. Differences were considered statistically significant when p < 0.05. RESULTS: Anterior teeth, maxillary premolars, and molars presented better results than mandibular premolars and molars (p < 0.05). Mandibular premolars presented a high incidence of a short length of obturation (33.34%) and mandibular molars presented a high incidence of overfilling (6.55%). The majority of the treatment analyzed (62.46%) fulfilled all the criteria showing acceptable working length, taper, and density of obturation. Instrument fractures occurred in eighteen root canals (0.81%). CONCLUSIONS: The use of NiTi reciprocating instruments with the single-cone obturation technique provided an acceptable quality of endodontic treatment in the majority of the cases performed by undergraduate students.

Location of the Second Mesiobuccal Canal of Maxillary Molars in a Brazilian Subpopulation: Analyzing Using Cone-beam Computed Tomography.

AIM: This study aimed to evaluate the spatial location of the second mesiobuccal canal (MB2) of maxillary molars (MMs), using cone-beam computed tomography (CBCT), in a Brazilian subpopulation. MATERIALS AND METHODS: The CBCT examination of 250 patients performed on the Eagle 3D device was analyzed, totaling 787 MMs. Using the Radiant Dicom Viewer software, measurements were made of the distances, in millimeters (mm), between the first mesiobuccal canal (MB1), MB2, and palatal (P) canal inputs, from the axial sections. The Image J software evaluated the angle formed by the lines. The data obtained were analyzed statistically by Fisher's exact and Chi-square tests with a significance of 5%. RESULTS: The prevalence of MB2 canals observed was 76.44 and 41.73% in the first and second molars (1MMs and 2MMs), respectively (p < 0.05). The average of the distances and angles performed, for the location of the MB2 canals of the analyzed teeth, were MB1-P = 5.83 mm, MB1-MB2 = 2.31 mm, and MB2 for the intersection of the connecting distance from MB2-T = 0.90 mm. The average angle formed between the MB1-P and MB1-MB2 distances was 25.89° and 19.68° for the 1MMs and 2MMs, respectively. It was also observed that 91.4 and 75.4% of the maxillary 1MMs and 2MMs, respectively, presented the MB2 canals mesially located at the line connecting the MB1-P canals (p < 0.0001). CONCLUSION: The MB2 canals were located mesially to the MB1 canal with an average distance of 2 mm between the canals. CLINICAL SIGNIFICANCE: The anatomical knowledge of the spatial location of the MB2 canal in different ethnicities is important for the planning and execution of endodontic treatment.

Influence of heat treatment of nickel-titanium instruments on the accuracy of an electronic apex locator integrated with endodontic motor.

Context: Manufacturers have produced a wide variety of nickel-titanium (NiTi) alloys, but the available literature is limited on the accuracy of some integrated electronic apex locators (EAL) used with different NiTi heat treatments in working length (WL) determination. Aim: This study aims to evaluate ex vivo , the influence of different heat treatments of NiTi instruments, and the diameter of the apical preparation on the accuracy of an EAL used during root canal preparation using an integrated EAL and motor unit. Materials and Methods: Nineteen extracted human mandibular incisors were included in the study. The WL control was determined by the visual method. Instruments of Mtwo, Reciproc, Reciproc Blue, WaveOne Gold, Twisted File Adaptive, and Hyflex CM systems, with diameters from 0.25 mm to 0.50 mm, were used to measure WL during root canal preparation. The electrical resistivity of instruments with a diameter of 0.25 mm from each system was evaluated using an Inductance, Capacitance, and Resistance (LCR) meter. Statistical Analysis Used: Data were statistically analyzed using Fisher's exact test and Kruskal-Wallis test. Results: The different heat treatments and different diameters did not influence the precision of the EAL (P > 0.05). Conclusion: The heat treatment and the diameter of the apical preparation did not influence the accuracy of WL determination by an EAL integrated with the endodontic motor.

Comparative in vitro study of intracanal Enterococcus faecalis reduction using photosensitizers in aPDT

Aim: To compare Enterococcus faecalis reduction after antimicrobial photodynamic therapy (aPDT) used with methylene blue, toluidine blue, tannin, and curcumin as photosensitizers, an adjunct to endodontic chemomechanical preparation (CMP) in root canals of human teeth. Methods: A total of 120 single-rooted teeth were divided into 6 groups (n = 20): G1- CMP and 2.5% sodium hypochlorite (NaOCl); G2- CMP and saline solution; G3- CMP, 2.5% NaOCl, and aPDT with 0.005% methylene blue; G4- CMP, 2.5% NaOCl, and aPDT with 0.005% toluidine blue; G5- CMP, 2.5% NaOCl, and aPDT with 0.005% tannin; and G6- CMP, 2.5% NaOCl, and aPDT with 0.005% curcumin. A portable semiconductor laser was used (660 nm, 100 mW, 1.8 J, 180s) in groups 1, 2, 3, 4, 5, and a blue LED light-curing (420-480 nm, 1200 mV/cm2 ) in G6. For all groups, a 5 min pre-irradiation time was applied. Samples were collected before (initial collection), immediately after (intermediate collection) and 7 days after CMP (final collection) for colony-forming unit (CFU) counting. The Kruskal-Wallis test and analysis of variance (ANOVA) were performed (p < 0.05; 95% confidence interval). Results: In between-group comparisons, there was no significant difference observed in the number of CFUs at the initial (p >< 0.001) and final collections (p >< 0.001) for G2 and G3. In within-group comparisons, the number of CFUs showed a decreasing trend in G4 (p = 0.007) and G5 (p = 0.001). Conclusion: Photosensitizers promoted E. faecalis reduction, with better results for tannin and curcumin. Alternative photosensitizers should be the focus of further studies.>< 0.05; 95% confidence interval). Results: In between-group comparisons, there was no significant difference observed in the number of CFUs at the initial (p < 0.001) and final collections (p >< 0.001) for G2 and G3. In within-group comparisons, the number of CFUs showed a decreasing trend in G4 (p = 0.007) and G5 (p = 0.001). Conclusion: Photosensitizers promoted E. faecalis reduction, with better results for tannin and curcumin. Alternative photosensitizers should be the focus of further studies.>< 0.001) and final collections (p < 0.001) for G2 and G3. In within-group comparisons, the number of CFUs showed a decreasing trend in G4 (p = 0.007) and G5 (p = 0.001). Conclusion: Photosensitizers promoted E. faecalis reduction, with better results for tannin and curcumin. Alternative photosensitizers should be the focus of further studies>< 0.001) for G2 and G3. In within-group comparisons, the number of CFUs showed a decreasing trend in G4 (p = 0.007) and G5 (p = 0.001). Conclusion: Photosensitizers promoted E. faecalis reduction, with better results for tannin and curcumin. Alternative photosensitizers should be the focus of further studies

Optimum glide path motion is safer than continuous rotation of files in glide path preparation.

This study evaluated the resistance to flexural fatigue and torsional strength of files for glide path preparation in continuous rotation or Optimum Glide Path motion (OGP). ScoutRace 15.02 and ProGlider 16.02 files were used in a dynamic testing device during preparation of simulating curved root canals (40-degree curvature and 5 mm radius). For the torsional test, a machine was used to test torsion measured maximum torsional strength (N.cm). Two-way anova and Tukey's multiple comparisons test were used for statistical analysis. Files in OGP motion had a statistically better resistance to flexural fatigue (P < 0.05). ProGlider files took longer time to failure than ScoutRace files only when OGP was used (P < 0.05). The torsional test revealed that OGP produced significantly less torsional stress than rotary motions for both types of glide path files (P < 0.05) In conclusion, OGP motion increased substantially the mechanical safety of endodontic glide path files.

Resistência à fadiga cíclica dos instrumentos Reciproc e Mtwo nos movimentos rotatório e reciprocante / Resistance to cyclic fatigue of Reciproc and Mwto files on continuous rotation and reciprocating movements

Objetivo: O objetivo do presente estudo foi avaliar a influência da liga (NiTi convencional e M-Wire) e do movimento (reciprocante e rotação contínua) na resistência à fadiga cíclica. Métodos: Quinze limas Reciproc R25 (VDW GmbH, Munique, Alemanha) foram usadas em movimento reciprocante (MR), enquanto trinta limas Mtwo 25.07 (VDW GmbH, Munique, Alemanha) foram usadas em MR (n=15) ou em rotação contínua (RC) (n=15). Os instrumentos foram submetidos a ensaios dinâmicos movidos por motor elétrico, que permitiram reproduzir o movimento de pecking motion, a 300rpm de velocidade. Os instrumentos simularam a instrumentação de um canal radicular curvo com 40o e 5mm de raio de curvatura. A fratura dos instrumentos foi detectada por um sensor digital, e o tempo e o número de ciclos foram registrados. Os dados foram analisados estatisticamente pelos testes ANOVA e de Tukey (p<0,05). Resultados: Os instrumentos Reciproc R25 movidos por MR alcançaram número significativamente maior (p<0,05) de ciclos antes da fratura (1.777,68±334,2 ciclos), quando comparados aos instrumentos MT 25.07 movidos por MR (610,67±126,3 ciclos) ou RC (432,23±183,2 ciclos). Conclusões: O movimento reciprocante mostrou resistência à fadiga cíclica significativamente maior, e os instrumentos de NiTi M-Wire apresentaram maior resistência à fadiga cíclica do que os instrumentos rotatórios de NiTi convencional (AU).

Objective: The aim of present study was to evaluate the influence of alloy (conventional NiTi and M-Wire NiTi) and movement (reciprocating movement and continuous rotation) on resistance to cyclic fatigue. Methods: Fifteen Reciproc R25 files (VDW GmbH, Munich, Germany) were used in reciprocation motion (RM), while thirty MTwo 25/.07 files (VDW GmbH, Munich, Germany) were used either in RM (n=15) or in continuous rotation (CR) (n=15). The files were submitted to dynamic assays device moved by electric engine that allowed the reproduction of pecking motion under 300 rpm of speed. The files act simulating the instrumentation of a curved root canal with 40º and 5-mm of curvature radius. The fracture was detected by the device sensor and the time and number of cycles were obtained. Data were statistically analyzed by ANOVA and Tukeys tests (p<0.05). Results: The Reciproc R25 instruments moved by RM reached significantly higher number (p<0.05) of cycles before fracture (1777.68 ± 334.2 cycles) when compared with MTwo 25/.07 instruments moved by RM (610.67 ± 126.3 cycles) or CR (432.23 ± 183.2 cycles). Conclusions: The reciprocation motion showed significantly greater cyclic fatigue resistance and the M-Wire NiTi files showed higher cyclic fatigue resistance than conventional NiTi rotary files (AU).

Analysis of Demineralized Chemical Substances for Disinfecting Gutta-percha Cones.

INTRODUCTION: The aim of the present research was to evaluate the effectiveness of 5% malic acid, 17% EDTA and 10% citric acid solutions used to disinfect gutta-percha cones contaminated by Enterococcusfaecalis (ATCC 29212). METHODS AND MATERIALS: Two hundred and ten previously sterilized gutta-percha cones were contaminated with E. faecalis at concentration of 1.5×108 CFU/mL. The cones were immersed in 5% malic acid, 17% EDTA, 10% citric acid, 1% NaOCl and 2.5% NaOCl for 1, 5 and 10 min. Then each cone was kept in Eppendorf tubes containing BHI sterile solution at 37°C for 48 h. The presence of turbidity in BHI solution was analyzed. The results were statistically analyzed by Kruskal-Wallis test and 5% Dunn comparisons. P-value was considered statistically significant when P<0.05. RESULTS: Regardless of exposure time, 1% NaOCl and 2.5% NaOCl were the most effective agents for rapid disinfection of gutta-percha cones (P<0.001). All specimens immersed in experimental demineralized solutions presented bacterial growth (P>0.05). CONCLUSION: Demineralized solutions tested were not effective for elimination of Enterococcus faecalis on the surface of gutta-percha cones.

Effect of different torques in cyclic fatigue resistance of K3 rotary instruments

Aim: To assess the effect of different torque values on cyclic fatigue resistance of K3 rotary nickel-titanium (NiTi) files. Methods: Eighty K3 files, size 25 mm, taper 0.04 were divided in 4 groups according to different torques (0.5, 1, 2 and 6 Ncm) and were submitted to a cyclic fatigue test. This test was performed with a device that allowed the file to rotate inside a stainless steel artificial curved canal, simulating the pecking motion. Files rotated until fracture occurred and time to failure was recorded in seconds with a stopwatch. Data were analyzed by ANOVA and Tukey tests (p<0.05). Results: All groups were compared and only the group of 6 N.cm showed statistically significant difference (p=0.0002). Conclusions: For #25.04 K3 files, the evaluated torques up to 2 N.cm had no influence on cyclic fatigue resistance. Using 6 N.cm torque value resulted in lower resistance to cyclic fatigue.

Penetration of a resin-based filling material into lateral root canals and quality of obturation by different techniques.

The aim of this study was to evaluate the penetration of a resin/polyester polymer-based material (Resilon Real Seal; SybronEndo Corp., Orange, USA) into simulated lateral canals, and the quality of obturations by different techniques. A total of 30 standardized simulated canals were divided into three groups according to the technique of obturation used: MS (McSpadden), SB (SystemB/Obtura II), and LC (Lateral Condensation). To analyze the penetration of the filling material, the simulated canals were digitalized and the images were analyzed using the Leica QWIN Pro v2.3 software. The data of the middle and apical thirds were separately submitted to analysis of variance (ANOVA), followed by the Tukey's test for the comparison of the techniques. Results showed a significant difference (p < 0.05) between groups (LC < SB) in the middle third, and a significant difference (p < 0.05) between groups (LC < SB and MS < SB) in the apical third. To analyze the quality of the obturations, the canals were radiographed and evaluated by three examiners. The Kappa test on interexaminer agreement and the nonparametric Kruskal-Wallis test indicated no significant difference between filling techniques. It was concluded that Resilon achieves greater levels of penetration when associated with thermoplastic obturation techniques.

Penetration of a resin-based filling material into lateral root canals and quality of obturation by different techniques

The aim of this study was to evaluate the penetration of a resin/polyester polymer-based material (Resilon Real Seal; SybronEndo Corp., Orange, USA) into simulated lateral canals, and the quality of obturations by different techniques. A total of 30 standardized simulated canals were divided into three groups according to the technique of obturation used: MS (McSpadden), SB (SystemB/Obtura II), and LC (Lateral Condensation). To analyze the penetration of the filling material, the simulated canals were digitalized and the images were analyzed using the Leica QWIN Pro v2.3 software. The data of the middle and apical thirds were separately submitted to analysis of variance (ANOVA), followed by the Tukey’s test for the comparison of the techniques. Results showed a significant difference (p < 0.05) between groups (LC < SB) in the middle third, and a significant difference (p < 0.05) between groups (LC < SB and MS < SB) in the apical third. To analyze the quality of the obturations, the canals were radiographed and evaluated by three examiners. The Kappa test on interexaminer agreement and the nonparametric Kruskal-Wallis test indicated no significant difference between filling techniques. It was concluded that Resilon achieves greater levels of penetration when associated with thermoplastic obturation techniques.

Not all electronic foramen locators are accurate in teeth with enlarged apical foramina: an in vitro comparison of 5 brands.

INTRODUCTION: Electronic working length measurement during root canal treatment in teeth with enlarged apical foramina is a challenge. The aims of this in vitro study were (1) to assess the influence of foramen widening on the accuracy of 5 different electronic foramen locators (EFLs) and (2) to compare the accuracy of EFLs in different foramen sizes. METHODS: The following EFLs were used: MiniApex, Root ZXII, iPex, Propex II, and Elements Apex Locator. Each EFL was used in 3 groups (n = 20) of extracted teeth, with foramen diameters of 0.27 mm (G27), 0.47 mm (G47), and 0.72 mm (G72). Working length was measured according to manufacturer's instructions and compared with visual measurements (control method). Results were classified as accurate (equal or differences ≤ 0.05 mm) or inaccurate (differences > 0.5 mm). RESULTS: In G27, all EFLs yielded accurate findings (intragroup reliability; Fisher exact test, P < .05), compared with only MiniApex, Root ZXII, and Elements Apex Locator in G47 and G72. MiniApex, Root ZXII, and Elements Apex Locator were similarly accurate regardless of foramen size. iPex and Propex II were the least accurate among the devices tested, and foramen diameter influenced their accuracy, with greater diameters yielding poorer EFL performance. CONCLUSIONS: Foramen diameter did not influence the accuracy of MiniApex, Root ZXII, and Elements Apex Locator EFLs. iPex and Propex II showed decreased accuracy as foramen size increased.

Effect of chemical and Er:YAG laser treatment on bond strength of root canal resin-based sealers.

Different treatments of dentin walls, as laser irradiation, prior to obturation can influence the adhesion ability of endodontic sealers. Therefore, the objective of this study was to compare in vitro the shear bond strength of four resin-based sealers to dentin treated with citric acid solution or erbium: yttrium, aluminum, garnet (Er:YAG) irradiation. A total of 240 slices with 1.6 mm of thickness were cut using middle third of 84 teeth. Each slice was widened using a #45 taper.06 rotary K3 instrument. The sample was divided into groups according to dentin pretreatment (15 % citric acid or Er:YAG laser) and sealer used (AH Plus, Acroseal, EndoREZ, or RealSeal). Shear bond strength was measured using a universal materials testing machine. As results, significant differences were found when comparing sealers between all groups (p < 0.05) by Kruskal-Wallis test, regardless of the pretreatment used. Comparing pretreatments, 15 % citric acid solution had better outcomes than Er:YAG laser, with significant differences in all groups, except for Acroseal groups (p < 0.05). It was concluded that RealSeal and 15 % citric acid solution achieved the best results regarding the sealer and pretreatment used, respectively.

Adhesion of four endodontic sealers to root dentin conditioned with different chemical solutions / Adesão de quatro cimentos endodônticos em dentina condicionada com diferentes soluções químicas

Objective - To evaluate in vitro adhesion of endodontic sealers Rickert, AH Plus, Sealapex and Epiphany to dentin previously conditioned with one of two different chemical solutions. Methods - A total of 80 specimens were made up with bovine incisive teeth that were prepared by cutting predetermined sections and wearing them, producing standard experimental samples. Forty samples were treated with 2.5% sodium hypochlorite and divided into four groups with 10 specimens each, to be coated with the different sealers. Dentin of other forty samples was treated with 17% EDTA, and these samples were also divided into four groups. Prepared specimens were hydrated uniformly, dried, bonded and kept at 37°C and 100% relative humidity. After 72 hours, specimens were analyzed using an Instron universal testing machine in traction mode. Data were analyzed by Kruskal-Wallis test (?=0.05). Results - EDTA treatment led to the greatest adhesiveness in all experimentalgroups. Conclusion - It was concluded that conditioning of the surface with chelating agents increase adhesiveness of the tested sealers and similar behavior was observed in the adhesion of epoxy-based and methacrylate-based sealers.

Objetivo - Avaliar in vitro a adesão dos cimentos endodônticos Rickert, AH Plus, Sealapex e Epiphany à dentina previamente tratada por duas soluções irrigadoras. Métodos - Foram empregados 80 corpos de prova obtidos a partir de dentes incisivos bovinos que foram preparados por cortes e desgastes pré-estabelecidos, resultando em modelos experimentais padronizados. Quarenta dessas amostras foram tratadas com hipoclorito de sódio 2,5% e subdivididas em quatro grupos de 10 espécimes para cada cimento. As demais 40 amostras tiveram a dentina tratada com EDTA a 17% e foram divididos igualmente em 4 grupos. Os espécimes preparados foram uniformemente hidratados, secos, receberam os cimentos, e foram mantidos sob umidade relativa a 37ºC. Após 72 horas os espécimes foram submetidos a testes de tração com auxilio da máquina de ensaio universal Instron, sendo os dados analisados pelo teste de Kruskal-Wallis (?=0.05). Resultados - O tratamento com EDTA proporcionou maiores índices de adesão para todos os grupos experimentais (p<0.05). Conclusão - Pode-se concluir que o tratamento da superfície com agente quelante, aumenta a capacidade de adesão dos cimentos testados. Não houve diferença na adesão dos cimentos a base de resina epóxica e a base de metacrilatos.

Resistance to flexural fatigue of Reciproc R25 files under continuous rotation and reciprocating movement.

INTRODUCTION: The aim of the present work was to evaluate the resistance to flexural fatigue of Reciproc R25 nickel-titanium files, 25 mm, used in continuous rotation motion or reciprocation motion, in dynamic assays device. METHODS: Thirty-six Reciproc R25 files were divided into 2 groups (n = 18) according to kinematics applied, continuous rotary (group CR) and reciprocation motion (group RM). The files were submitted to dynamic assays device moved by an electric engine with 300 rpm of speed that permitted the reproduction of pecking motion. The files run on a ring's groove of temperate steel, simulating instrumentation of a curved root canal with 40° and 5 mm of curvature radius. The fracture of file was detected by sensor of device, and the time was marked. The data were analyzed statistically by Student's t test, with level of significance of 95%. RESULTS: The instruments moved by reciprocating movement reached significantly higher numbers of cycles before fracture (mean, 1787.78 cycles) when compared with instruments moved by continuous rotary (mean, 816.39 cycles). CONCLUSIONS: The results showed that the reciprocation motion improves flexural fatigue resistance in nickel-titanium instrument Reciproc R25 when compared with continuous rotation movement.

Solvency capacity of gutta-percha and Resilon using chloroform, eucalyptol, orange oil or xylene / Capacidade de solvência da guta-percha e do Resilon utilizando clorofórmio, eucaliptol, óleo de laranja ou xilol

Objective - The aim of the study was to evaluate the ability of 4 solvents (chloroform, eucalyptol, xylene and orange oil to dissolve gutta-percha and Resilon under two experimental periods (5 and 15 minutes). Methods - Eighty pellets of gutta-percha and 80 pellets of Resilon were weighed with a precision balance before and after immersion in solvents during experimental periods of 5 and 15 minutes. The differences between the initial and final weights and resulting losses masses were tabulated. Results - The results showed that chloroform presented the greatest ability to dissolve gutta-percha and the polyester polymer Resilon (p <0.05) in both experimental periods. Generally, other solvents currently used clinically (eucalyptol, xylene and orange oil) do not showed adequate ability to dissolve both materials. Conclusion - Independent of contact period, the most effective solvency for gutta-percha and Resilon in decreasing order was: chloroform, xylene, orange oil and eucalyptol.

Objetivo - Avaliar a capacidade de 4 solventes (clorofórmio, eucaliptol, óleo de casca de laranja e xilol) na dissolução da guta-percha e do Resilon® em dois períodos experimentais (5 e 15 minutos). Métodos - Oitenta pellets de guta-percha e 80 pellets de Resilon® foram pesados com uma balança de precisão antes e após a imersão nos solventes pelos tempos experimentais. As diferenças entre os pesos iniciais e finais foram calculadas e o total de massa perdida foram tabulados. Resultados - Os resultados mostraram que o clorofórmio apresentou a maior capacidade de dissolver Resilon® (p <0,05) em ambos os períodos experimentais. Sobre a solubilidade da guta-percha, foi observado comportamento semelhante para o clorofórmio, quando comparado aos demais solventes (p <0,05), exceto quando comparado com xilol em 5 minutos. De modo geral, os outros solventes utilizados no estudo (xilol, eucaliptol e óleo de casca de laranja) não mostraram capacidade suficiente para dissolver ambos os materiais de forma adequada. Conclusão - Independente do período de contato, a efetividade na dissolução da guta-percha e Resilon® em ordem decrescente foi: clorofórmio, óleo de casca de laranja, eucaliptol e xilol.

In vitro analysis of thermocompaction time and gutta-percha type on quality of main canal and lateral canals filling.

The aim of this study was to evaluate the quality of filling in main and lateral root canals performed with the McSpadden technique, regarding the time spent on the procedure and the type of gutta-percha employed. Fifty simulated root canals, made with six lateral canals placed two apiece in the cervical, middle and apical thirds of the root, were divided into 5 groups. Group A: McSpadden technique with conventional gutta-percha, performed with sufficient time for canal filling; Group B: McSpadden technique with conventional gutta-percha, performed in twice the mean time used in Group A; Group C: McSpadden technique with TP gutta-percha, performed with sufficient time for canal filling; Group D: McSpadden technique with TP gutta-percha, performed in twice the mean time used in Group C; Group E: lateral condensation technique. Images of the filled root canals were taken using a stereomicroscope and analyzed using the Leica QWIN Pro software for filling material flow, gutta-percha filling extension and sealer flow. Data were analyzed by analysis of variance (ANOVA) and Tukey test (p < 0.05). The best values of penetration in lateral canals in the middle third occurred in the groups where TP gutta-percha was used. However, in the apical third, group B showed the best values. Although a longer time of compactor use allows greater penetration of the filling material into the lateral canals, the presence of voids resulted in bad quality radiographic images, suggesting porosity. The best quality of filling material was observed in Group A (McSpadden technique with conventional Gutta-Percha, performed with sufficient time for root canal filling).

In vitro analysis of thermocompaction time and gutta-percha type on quality of main canal and lateral canals filling

The aim of this study was to evaluate the quality of filling in main and lateral root canals performed with the McSpadden technique, regarding the time spent on the procedure and the type of gutta-percha employed. Fifty simulated root canals, made with six lateral canals placed two apiece in the cervical, middle and apical thirds of the root, were divided into 5 groups. Group A: McSpadden technique with conventional gutta-percha, performed with sufficient time for canal filling; Group B: McSpadden technique with conventional gutta-percha, performed in twice the mean time used in Group A; Group C: McSpadden technique with TP gutta-percha, performed with sufficient time for canal filling; Group D: McSpadden technique with TP gutta-percha, performed in twice the mean time used in Group C; Group E: lateral condensation technique. Images of the filled root canals were taken using a stereomicroscope and analyzed using the Leica QWIN Pro software for filling material flow, gutta-percha filling extension and sealer flow. Data were analyzed by analysis of variance (ANOVA) and Tukey test (p < 0.05). The best values of penetration in lateral canals in the middle third occurred in the groups where TP gutta-percha was used. However, in the apical third, group B showed the best values. Although a longer time of compactor use allows greater penetration of the filling material into the lateral canals, the presence of voids resulted in bad quality radiographic images, suggesting porosity. The best quality of filling material was observed in Group A (McSpadden technique with conventional Gutta-Percha, performed with sufficient time for root canal filling).