Evaluation of flow and filling of root canal sealers using different methodologies / Avaliação do escoamento e preenchimento de cimentos obturadores utilizando diferentes metodologias

Abstract Introduction Flow and filling ability of root canal sealers are indispensable for hermetic sealing of the root canal. Micro-computed tomography (micro-CT) can be used as a complementary methodology to evaluate such properties. Objective To evaluate the flow and filling ability of AH Plus, Endofill and Sealapex by conventional methodology and micro-CT. Material and method The flow of the sealers was analyzed according to ISO 6876/2012 and complemented by the area evaluation. Glass plates were manufactured with diameters of 1×1×2 mm and 1×1×1 mm (length, width and height), with a central cavity and four grooves in the horizontal and vertical directions. Each material was placed in the central cavity. Another glass plate and a metal weight were placed on the cement and kept for 10 minutes. The glass plate/sealer set was scanned using micro-CT. The flow was calculated by linear measurement of the material in the grooves. The central filling (mm3) was calculated in the central cavity and the lateral filling was measured up to 2 mm from the central cavity. Data were submitted to ANOVA/Tukey tests (α=0.05). Result All evaluated sealers presented flow according to ISO 6876 standards. The materials showed central cavity filling capacity higher than 80% and lateral filling greater than 75%. There was no difference in flow (mm and mm2) and in the filling ability (mm3) provided by the materials (p>0.05). Conclusion All evaluated root canal sealers showed adequate flow and filling capacity, suggesting their clinical application.

Resumo Introdução Escoamento e capacidade de preenchimento de cimentos obturadores são indispensáveis para um selamento hermético do canal radicular. Microtomografia computadorizada (micro-CT) pode ser utilizada como uma metodologia complementar para avaliação de tais propriedades. Objetivo Avaliar escoamento e capacidade de preenchimento de AH Plus, Endofill e Sealapex, por meio de metodologia convencional e micro-CT. Material e método O escoamento dos cimentos foi analisado de acordo com as normas ISO 6876/2012 e complementado pela avaliação em área. Placas de vidro foram confeccionadas nos diâmetros de 1×1×2 mm e 1×1×1 mm (comprimento, largura e altura), com uma cavidade central e quatro canaletas nas direções horizontal e vertical. Cada material foi colocado na cavidade central. Outra placa de vidro e um peso de metal foram colocados sobre o cimento e mantidos por 10 minutos. O conjunto placa de vidro/cimento foi escaneado usando micro-CT. O escoamento foi calculado por medição linear do material nas canaletas. O preenchimento (mm3) central foi calculado na cavidade central e o preenchimento lateral foi medido até 2 mm a partir da cavidade central. Os dados foram submetidos aos testes ANOVA/Tukey (α=0.05). Resultado Todos os cimentos avaliados apresentaram escoamento de acordo com as normas ISO 6876. Os materiais mostraram capacidade de preenchimento da cavidade central superior a 80% e preenchimento lateral superior a 75%. Não houve diferença no escoamento (mm e mm2) e na capacidade de preenchimento (mm3) proporcionada pelos materiais (p>0.05). Conclusão Todos os cimentos obturadores avaliados mostraram adequado escoamento e capacidade de preenchimento, sugerindo a aplicação clínica dos mesmos.

Ytterbium Oxide as Radiopacifier of Calcium Silicate-Based Cements. Physicochemical and Biological Properties.

This study evaluated physicochemical properties, cytotoxicity and bioactivity of MTA Angelus (MTA), calcium silicate-based cement (CSC) and CSC with 30% Ytterbium oxide (CSC/Yb2O3). Setting time was evaluated using Gilmore needles. Compressive strength was evaluated in a mechanical machine. Radiopacity was evaluated using radiographs of materials and an aluminum scale. Solubility was evaluated after immersion in water. Cell viability was evaluated by means of MTT assay and neutral red staining, and the mineralization activity by using alkaline phosphatase activity and Alizarin Red staining. The data were submitted to ANOVA, Tukey and Bonferroni tests (5% significance). The bioactive potential was evaluated by scanning electron microscopy. The materials presented similar setting time. MTA showed the lowest compressive strength. MTA and CSC/Yb2O3 presented similar radiopacity. CSC/Yb2O3 showed low solubility. Saos-2 cell viability tests showed no cytotoxic effect, except to 1:1 dilution in NR assay which had lower cell viability when compared to the control. ALP at 1 and 7 days was similar to the control. MTA and CSC had greater ALP activity at 3 days when compared to control. All the materials present higher mineralized nodules when compared with the control. SEM analysis showed structures suggesting the presence of calcium phosphate on the surface of materials demonstrating bioactivity. Ytterbium oxide proved to be a properly radiopacifying agent for calcium silicate-based cement since it did not affected the physicochemical and biological properties besides preserving the bioactive potential of this material.

Ytterbium oxide as radiopacifier of calcium silicate-based cements. physicochemical and biological properties

Abstract This study evaluated physicochemical properties, cytotoxicity and bioactivity of MTA Angelus (MTA), calcium silicate-based cement (CSC) and CSC with 30% Ytterbium oxide (CSC/Yb2O3). Setting time was evaluated using Gilmore needles. Compressive strength was evaluated in a mechanical machine. Radiopacity was evaluated using radiographs of materials and an aluminum scale. Solubility was evaluated after immersion in water. Cell viability was evaluated by means of MTT assay and neutral red staining, and the mineralization activity by using alkaline phosphatase activity and Alizarin Red staining. The data were submitted to ANOVA, Tukey and Bonferroni tests (5% significance). The bioactive potential was evaluated by scanning electron microscopy. The materials presented similar setting time. MTA showed the lowest compressive strength. MTA and CSC/Yb2O3 presented similar radiopacity. CSC/Yb2O3 showed low solubility. Saos-2 cell viability tests showed no cytotoxic effect, except to 1:1 dilution in NR assay which had lower cell viability when compared to the control. ALP at 1 and 7 days was similar to the control. MTA and CSC had greater ALP activity at 3 days when compared to control. All the materials present higher mineralized nodules when compared with the control. SEM analysis showed structures suggesting the presence of calcium phosphate on the surface of materials demonstrating bioactivity. Ytterbium oxide proved to be a properly radiopacifying agent for calcium silicate-based cement since it did not affected the physicochemical and biological properties besides preserving the bioactive potential of this material.

Resumo Este estudo avaliou as propriedades físico-químicas, citotoxicidade e bioatividade do MTA Angelus (MTA), cimento à base de silicato de cálcio (CSC) e CSC com 30% de óxido de itérbio (CSC/Yb2O3). O tempo de presa foi avaliado usando agulhas Gilmore. A resistência à compressão foi avaliada em uma máquina mecânica. A radiopacidade foi avaliada utilizando radiografias dos materiais e uma escala de alumínio. A solubilidade foi avaliada após imersão em água. A viabilidade celular foi avaliada por meio do ensaio MTT e coloração de vermelho neutro (NR), e a atividade de mineralização por meio da atividade da fosfatase alcalina e a coloração com Vermelho de Alizarina. Os dados foram submetidos aos testes ANOVA, Tukey e Bonferroni (5% de significância). O potencial bioativo foi avaliado por microscopia eletrônica de varredura. Os materiais apresentaram tempo de presa semelhante. O MTA mostrou menor resistência à compressão. MTA e CSC/Yb2O3 apresentaram radiopacidade semelhante. CSC/Yb2O3 apresentou menores valores de solubilidade. A viabilidade celular realizada pelos ensaios de MTT e NR não revelaram efeitos ctotóxicos em todas as diluições, exceto na diluição 1:1 no NR, o qual mostrou baixa viabilidade celular (p<0.05) em todos materiais testados quando comparado ao controle. A atividade de ALP em 1 e 7 dias foi similar ao controle (p>0.05). MTA e CSC tiveram significante aumento na atividade de ALP aos 3 dias quando comarados ao controle (p>0.05). Todos os materiais apresentaram grande produção de nódulos mineralizados quando comparados ao controle (P<0.05). A análise da SEM mostrou estruturas que sugerem a presença de depósitos de fosfato de cálcio na superfície dos materiais demonstrando bioatividade. O Yb2O3 mostrou ser um agente radiopacificador adequado em cimentos à base de silicato de cálcio uma vez que não afetou as propriedades físico-químicas e biológicas e ainda preservou o potencial bioativo desse material.

Radiographic and micro-computed tomography classification of root canal morphology and dentin thickness of mandibular incisors.

CONTEXT: Root canal anatomy is evaluated using different methodologies. AIMS: The aim of this study is to evaluate and classify root canal morphology and dentin thicknesses (DT), comparing radiographic and micro-computed tomography (CT) analysis. MATERIALS AND METHODS: Canal diameter and DT of mandibular incisors (n = 520) were evaluated using digital radiographs in buccolingual (BL) and mesiodistal (MD) directions. The diameter ratio (DR) BL/MD was classified: flattened (FL, DR >4); oval (OV, 2≤ DR ≥4); rounded (RN, 1.1< DR >2); round (RO, 0.9≤ DR ≥1.1); and with BL flatness (BL, DR <0.9). OV (n = 110) were subjected to micro-CT. DT and DR were evaluated at 3, 6, and 9 mm. ANOVA, Tukey, and paired Wilcoxon tests (P < 0.05) were used. RESULTS: Radiographic classification was 23.3% FL, 41.3% OV, 27.3% RN, 4.5% RO, and 3.6% BL. DT was similar. Radiographic DT at 3 and 9 mm was greater than micro-CT (P < 0.05) and was similar at 6 mm (P > 0.05). DR differed between the analyses. Oval canals were predominant at all levels radiographically and at 9 and 6 mm in micro-CT analysis, with greater variation at 3 mm. CONCLUSION: Oval root canals are predominant in mandibular incisors at 9 mm. Radiographic DT is larger than observed in micro-CT at 3 and 9 mm, and the classification differed in each root level. The classification at 9 mm is indicated.

Cytocompatibility, physical properties, and antibiofilm activity of endodontic sealers with amoxicillin.

The aim was to evaluate the cytocompatibility of the AH Plus and Sealapex associated with amoxicillin (AA) in a quantity of 10% by total weight of the sealers, the flow and setting time of these sealers with 10%-0.25% AA and antibiofilm activity of these sealers associated with AA in a concentration that does not alter their physical properties (1%). Cytocompatibility was assessed by MTT, neutral red and cytoskeletal fluorescence assays. Setting time and flow was evaluated using the specifications of ISO 6876/2012. For the antibiofilm evaluation, materials were placed in direct contact with E. faecalis biofilm induced on dentin blocks. The incorporation of AA into the sealers did not diminish the viability of the fibroblasts and did not cause structural changes in the cytoskeletal. The flow of AH Plus + AA at 1.0; 0.5 and 0.25%, and of Sealapex + AA at 5.5; 2.5; 1.0; 0.5 and 0.25% were within the specifications of the ISO 6876. AH Plus, and AH Plus + AA at 1.0; 0.50 and 0.25% presented a setting time of 730, 439, 455, and 474 min., respectively. Sealapex - pure or associated with AA did not set completely. The addition of 1% AA to the sealers did not increase their antibiofilm activity. It was concluded that the incorporation of 10% AA caused no toxic effects on fibroblasts, but harmed the physical properties. The addition of AA in concentration that does not affect the physical properties of the sealers did not increase their antibiofilm activity.

A Novel Model for Evaluating the Flow of Endodontic Materials Using Micro-computed Tomography.

INTRODUCTION: Flow and filling ability are important properties of endodontic materials. The aim of this study was to propose a new technique for evaluating flow using micro-computed tomographic (µCT) imaging. METHODS: A glass plate was manufactured with a central cavity and 4 grooves extending out horizontally and vertically. The flow of MTA-Angelus (Angelus, Londrina, PR, Brazil), zinc oxide eugenol (ZOE), and Biodentine (BIO) (Septodont, Saint Maur des Fossés, France) was evaluated using International Standards Organization (ISO) 6876/2002 and a new technique as follows: 0.05 ± 0.005 mL of each material was placed in the central cavity, and another glass plate and metal weight with a total mass of 120 g were placed over the material. The plate/material set was scanned using µCT imaging. The flow was calculated by linear measurement (mm) of the material in the grooves. Central cavity filling was calculated in mm3 in the central cavity. Lateral cavity filling (LCF) was measured by LCF mean values up to 2 mm from the central cavity. Data were analyzed statistically using analysis of variance and Tukey tests with a 5% significance level. RESULTS: ZOE showed the highest flow rate determined by ISO methodology (P < .05). Analysis performed using µCT imaging showed MTA-Angelus and ZOE had higher linear flow rates in the grooves. Central cavity filling was similar for the materials. However, LCF was higher for BIO versus ZOE. CONCLUSIONS: Although ZOE presented better flow determined by ISO methodology, BIO showed the best filling ability. The model of the technique proposed for evaluating flow using µCT imaging showed proper and reproducible results and could improve flow analysis.

Effect of ProTaper and Reciproc preparation and gutta-percha cone on cold lateral compaction.

CONTEXT: The effectiveness of cold lateral compaction depends on the root canal preparation and used gutta-percha cone. AIMS: The aim of this study is to evaluate finger spreader penetration into root canals prepared with ProTaper (PT) or Reciproc (Rec) systems and filled with gutta-percha cones with different tapers. MATERIALS AND METHODS: Twenty-four simulated root canals in resin blocks with 30° curvature were prepared up to PT F2 or Rec R25. They were divided into four experimental groups according to the master gutta-percha cone and preparation (25.02 or F2/PT, and 25.02 or R25/Rec). Cold lateral compaction was performed using a stainless steel finger spreader size B. The set cone-finger spreader-resin block was placed in a universal test machine, and a load up to 1.5 kg was applied on the finger spreader. The final distance between the finger spreader and apical preparation after load application was obtained. For comparison among the groups, data were submitted to ANOVA and Tukey's tests, with a significance level of 5%. RESULTS: Greater finger spreader penetration was observed for 0.02/Rec and 0.02/PT, followed by F2/PT and R25/Rec. CONCLUSION: The use of cones associated with PT and Rec preparations does not allow the finger spreader penetration up to the apical third.

Surface characteristics of reciprocating instruments before and after use--a SEM analysis.

The presence of debris, defects and deformations of endodontic reciprocating instruments before and after chemical-mechanical preparation (MCP) was analyzed using scanning electron microscopy (SEM). The following 26 instruments were divided into 2 groups: Waveone (n=13) and Reciproc (n=13) and examined by SEM (150 x magnification) prior to canal preparation at 2 and 4 mm from the tip. The instruments were used in the preparation of mesial root canals of 26 extracted human permanent mandibular molars. The instruments were then washed in ultrasonic bath and subjected to new microscopic analysis of debris and deformation by a score that used the presence or absence of irregular edges, grooves, microcavities and burrs as criteria. After the SEM analysis and with the scores of the examiners, the collected data were subjected to descriptive statistical analysis using the Kruskall-Walis and Mann Whitney test at a 5% significance level. All instruments examined presented debris before and after use. A statistically significant difference was found for defects and deformation between the groups (p<0.05). The presence of defects and deformities was higher in the WaveOne instruments, and Reciproc instruments presented a lower rate.

Surface Characteristics of Reciprocating Instruments Before and After Use - A SEM Analysis

The presence of debris, defects and deformations of endodontic reciprocating instruments before and after chemical-mechanical preparation (MCP) was analyzed using scanning electron microscopy (SEM). The following 26 instruments were divided into 2 groups: Waveone (n=13) and Reciproc (n=13) and examined by SEM (150 x magnification) prior to canal preparation at 2 and 4 mm from the tip. The instruments were used in the preparation of mesial root canals of 26 extracted human permanent mandibular molars. The instruments were then washed in ultrasonic bath and subjected to new microscopic analysis of debris and deformation by a score that used the presence or absence of irregular edges, grooves, microcavities and burrs as criteria. After the SEM analysis and with the scores of the examiners, the collected data were subjected to descriptive statistical analysis using the Kruskall-Walis and Mann Whitney test at a 5% significance level. All instruments examined presented debris before and after use. A statistically significant difference was found for defects and deformation between the groups (p<0.05). The presence of defects and deformities was higher in the WaveOne instruments, and Reciproc instruments presented a lower rate.

Analisou-se por meio de microscopia eletrônica de varredura) MEV, a presença de debris, defeitos e deformações dos instrumentos endodônticos reciprocantes antes e após o preparo químico-mecânico (PQM). Vinte e seis instrumentos foram divididos em 2 grupos: WaveOne (n=13) e Reciproc (n=13), eletromicrografados previamente ao PQM com aumento de 150×, a 2 e 4 mm da ponta. Os instrumentos foram utilizados no preparo de canais radiculares mesiais de 26 molares permanentes inferiores humanos extraídos. Após, foram lavados em cuba ultrassônica e submetidos a nova análise microscópica para visualizar detritos e deformações tendo como critérios um escore que avaliou a presença ou não de borda irregular, ranhura, microcavidade e rebarba. Após análise em MEV e de posse dos escores dos avaliadores, os dados coletados foram submetidos à analise estatística descritiva pelos testes de Kruskall-Walis e Mann Whitney, ao nível de significância de 5%. Todos os instrumentos analisados apresentaram detritos antes e após o uso. Houve diferença estatisticamente significante quanto a defeitos e deformações entre os grupos (p<0,05). A presença de defeitos e deformações foi maior nos instrumentos WaveOne, enquanto que para os instrumentos Reciproc tal índice foi menor.

Comparison of cyclic fatigue and torsional resistance in reciprocating single-file systems and continuous rotary instrumentation systems.

As compared with continuous rotary systems, reciprocating motion is believed to increase the fatigue resistance of NiTi instruments. We compared the cyclic fatigue and torsional resistance of reciprocating single-file systems and continuous rotary instrumentation systems in simulated root canals. Eighty instruments from the ProTaper Universal, WaveOne, MTwo, and Reciproc systems (n = 20) were submitted to dynamic bending testing in stainless-steel simulated curved canals. Axial displacement of the simulated canals was performed with half of the instruments (n = 10), with back-and-forth movements in a range of 1.5 mm. Time until fracture was recorded, and the number of cycles until instrument fracture was calculated. Cyclic fatigue resistance was greater for reciprocating systems than for rotary systems (P < 0.05). Instruments from the Reciproc and WaveOne systems significantly differed only when axial displacement occurred (P < 0.05). Instruments of the ProTaper Universal and MTwo systems did not significantly differ (P > 0.05). Cyclic fatigue and torsional resistance were greater for reciprocating systems than for continuous rotary systems, irrespective of axial displacement.

Influence of sealer placement technique on the quality of root canal filling by lateral compaction or single cone.

The aim of this study was to evaluate the influence of the sealer placement technique on the quality of root canal filling using Lateral Compaction (LC) or Single Cone (SC). In order to do that, 60 mesial roots of mandibular first molars were prepared and divided into 2 groups (n=30), according to the filling technique: LC and SC. Each group was subdivided into 3 subgroups (n=10), according to the different sealer placement methods: A: Master gutta-percha (GP) cone; B: Lentulo spiral; C: File. The roots were sectioned at 2, 4 and 6 mm from the apex and photographed with the aid of a digital microscope. Then, areas of GP, endodontic sealer and voids were measured, and these data were subjected to statistical analysis. LC technique showed no statistically difference (p>0.05) in the percentage of GP area, sealer and voids between the subgroups at any of the three levels. After use of SC, higher percentages of sealer area were found at all levels (p<0.01) when the sealer was placed with a file. At 2 mm, higher percentage of void areas (p<0.05) was observed when the cone was used, lower percentage with K-file and the lowest percentage with Lentulo. At 4 mm, cone showed higher percentage of void areas (p<0.05). At 6 mm, there were no significant differences (p>0.05) between the three methods. Considering these results, using an instrument for sealer placement was important in the SC technique to reduce voids. Regarding LC, the sealer placement techniques provided similar results.

Influence of Sealer Placement Technique on the Quality of Root Canal Filling by Lateral Compaction or Single Cone

The aim of this study was to evaluate the influence of the sealer placement technique on the quality of root canal filling using Lateral Compaction (LC) or Single Cone (SC). In order to do that, 60 mesial roots of mandibular first molars were prepared and divided into 2 groups (n=30), according to the filling technique: LC and SC. Each group was subdivided into 3 subgroups (n=10), according to the different sealer placement methods: A: Master gutta-percha (GP) cone; B: Lentulo spiral; C: File. The roots were sectioned at 2, 4 and 6 mm from the apex and photographed with the aid of a digital microscope. Then, areas of GP, endodontic sealer and voids were measured, and these data were subjected to statistical analysis. LC technique showed no statistically difference (p>0.05) in the percentage of GP area, sealer and voids between the subgroups at any of the three levels. After use of SC, higher percentages of sealer area were found at all levels (p<0.01) when the sealer was placed with a file. At 2 mm, higher percentage of void areas (p<0.05) was observed when the cone was used, lower percentage with K-file and the lowest percentage with Lentulo. At 4 mm, cone showed higher percentage of void areas (p<0.05). At 6 mm, there were no significant differences (p>0.05) between the three methods. Considering these results, using an instrument for sealer placement was important in the SC technique to reduce voids. Regarding LC, the sealer placement techniques provided similar results.

O objetivo deste estudo foi avaliar a influência das técnicas de inserção de cimento endodôntico na qualidade da obturação, usando Compactação Lateral Ativa (CLA) e Cone Único. Para tal, 60 raízes mesiais de primeiros molares inferiores foram preparadas e divididas em 2 grupos (n=30), de acordo com a técnica de obturação: CLA e Cone único. Cada grupo foi subdividido em 3 subgrupos (n=10), de acordo com as diferentes técnicas de inserção aplicadas: A - Cone de guta-percha principal; B - Lentulo; C - Lima. As raízes foram seccionadas a 2, 4 e 6 mm do ápice e fotografadas com microscópio digital. Então, as áreas de guta-percha, cimento endodôntico e falhas foram medidas e tais dados foram submetidos à análise estatística. CLA não revelou diferenças estatisticamente significantes (p>0,05) nas porcentagens das áreas de guta-percha, de cimento endodôntico e de falhas, em nenhum dos grupos ou níveis de corte. Com a aplicação da técnica do Cone Único, maiores porcentagens de área de cimento foram encontradas nos três níveis (p<0,01) quando este foi inserido por meio de uma lima. Aos 2 mm, a maior porcentagem de área de falhas (p<0,05) foi observada quando o cone foi utilizado. Uma porcentagem menor foi encontrada quando foi utilizada a lima; e a menor porcentagem foi observada com o Lentulo. Aos 4 mm, a inserção por meio do cone apresentou maior porcentagem de falhas (p<0,05). Aos 6 mm, não houve diferença estatisticamente significante (p>0,05) entre os três métodos. Considerando esses resultados, foi importante o uso de um instrumento para a inserção do cimento quando a técnica do Cone Único foi aplicada. Já com CLA, qualquer técnica de inserção de cimento apresentou resultados similares.

Evaluación comparativa in vitro de la capacidad de sellado del sistema de conductos radiculares por diferentes técnicas / Comparative in vitro evaluation of the sealing ability of the root canal system by different techniques

Objetivo. Evaluar in vitro la capacidad de sellado del conducto radicular utilizando las técnicas de condensación lateral activa, Híbrida de Tagger modificada, Thermafil y System B. Material y métodos. Fueron empleados 116 dientes humanos extraídos uniradiculares, incluidos en bloques de resina, seccionados longitudinalmente, unidos a un dispositivo con tornillos y divididos en cuatro grupos (n= 29). Después de la instrumentación con ayuda de fresas, fue confeccionada una depresión en cada tercio del conducto radicular en cada una de las mitades de la raíz. En seguida, los dientes fueron obturados con las citadas técnicas. Para la evaluación de la calidad de la obturación, fueron realizadas fotos con aumento de 1.5X y radiografías, sometidas a diferentes escores. Después se realizó el análisis estadístico tanto macroscópica como radiográficamente, por medio del test Chi-cuadrado (χ2). Resultados. La técnica Thermafil presentó mejores resultados en cuanto a la capacidad de llenado, número de fallas y homogeneidad (p < 0,05), seguida de la técnica Híbrida de Tagger modificada, System B y condensación lateral activa. Conclusiones. Thermafil fue la técnica que demostró ser macroscópica, radiográfica y homogéneamente superior a las otras técnicas evaluadas, en lo que se refiere al sellado de las depresiones y fallas confeccionadas (AU)

Objective. The aim of this study was to evaluate in vitro the sealing ability of the root canal using different techniques: cold lateral compaction, modified Hybrid Tagger, Thermafil and System B. Material and methods. Were used 116 human single-roots, included in resin blocks, sectioned longitudinally, attached to a device with screws and divided into four groups (n=29). After instrumentation using a bur, depression was made in each third of the root canal in each of the halves. Teeth were filled upon the different techniques. For evaluation of the quality, pictures were taken with a 1.5X magnification, photos and radiographs were utilized. After statistical analysis, were performed both macroscopic and radiographic evaluation, by Chi-square test (χ2). Results. The Thermafil technique showed better results in terms of sealing capacity, failures and homogeneity followed by modified Hybrid Tagger, the System B and cold lateral compaction. Conclusions. Thermafil was the technique that shown to be macroscopic, radiographic and homogeneously best over the other techniques evaluated in regard to the filling of the depressions made (AU)

The efficacy of the self-adjusting file and ProTaper for removal of calcium hydroxide from root canals.

OBJECTIVE: The goal of this study was to evaluate the efficacy of the Self-Adjusting File (SAF) and ProTaper for removing calcium hydroxide [Ca(OH)2] from root canals. MATERIAL AND METHODS: Thirty-six human mandibular incisors were instrumented with the ProTaper system up to instrument F2 and filled with a Ca(OH)2-based dressing. After 7 days, specimens were distributed in two groups (n=15) according to the method of Ca(OH)2 removal. Group I (SAF) was irrigated with 5 mL of NaOCl and SAF was used for 30 seconds under constant irrigation with 5 mL of NaOCl using the Vatea irrigation device, followed by irrigation with 3 mL of EDTA and 5 mL of NaOCl. Group II (ProTaper) was irrigated with 5 mL of NaOCl, the F2 instrument was used for 30 seconds, followed by irrigation with 5 mL of NaOCl, 3 mL of EDTA, and 5 mL of NaOCl. In 3 teeth Ca(OH)2 was not removed (positive control) and in 3 teeth canals were not filled with Ca(OH)2 (negative control). Teeth were sectioned and prepared for the scanning electron microscopy. The amounts of residual Ca(OH)2 were evaluated in the middle and apical thirds using a 5-score system. RESULTS: None of the techniques completely removed the Ca(OH)2 dressing. No difference was observed between SAF and ProTaper in removing Ca(OH)2 in the middle (P=0.11) and the apical (P=0.23) thirds. CONCLUSION: The SAF system showed similar efficacy to rotary instrument for removal of Ca(OH)2 from mandibular incisor root canals.

The efficacy of the self-adjusting file and ProTaper for removal of calcium hydroxide from root canals

OBJECTIVE: The goal of this study was to evaluate the efficacy of the Self-Adjusting File (SAF) and ProTaper for removing calcium hydroxide [Ca(OH)2] from root canals. MATERIAL AND METHODS: Thirty-six human mandibular incisors were instrumented with the ProTaper system up to instrument F2 and filled with a Ca(OH)2-based dressing. After 7 days, specimens were distributed in two groups (n=15) according to the method of Ca(OH)2 removal. Group I (SAF) was irrigated with 5 mL of NaOCl and SAF was used for 30 seconds under constant irrigation with 5 mL of NaOCl using the Vatea irrigation device, followed by irrigation with 3 mL of EDTA and 5 mL of NaOCl. Group II (ProTaper) was irrigated with 5 mL of NaOCl, the F2 instrument was used for 30 seconds, followed by irrigation with 5 mL of NaOCl, 3 mL of EDTA, and 5 mL of NaOCl. In 3 teeth Ca(OH)2 was not removed (positive control) and in 3 teeth canals were not filled with Ca(OH)2 (negative control). Teeth were sectioned and prepared for the scanning electron microscopy. The amounts of residual Ca(OH)2 were evaluated in the middle and apical thirds using a 5-score system. RESULTS: None of the techniques completely removed the Ca(OH)2 dressing. No difference was observed between SAF and ProTaper in removing Ca(OH)2 in the middle (P=0.11) and the apical (P=0.23) thirds. CONCLUSION: The SAF system showed similar efficacy to rotary instrument for removal of Ca(OH)2 from mandibular incisor root canals. .

Ex-vivo effect of intracanal medications based on ozone and calcium hydroxide in root canals contaminated with Enterococcus faecalis.

This ex vivo study evaluated the antibacterial effect of intracanal medications in root canals contaminated with Enterococcus faecalis. Fifty single-rooted human teeth were contaminated with E. faecalis (ATCC 29212) and incubated at 37°C for 21 days. The specimens were randomly divided into 5 groups according to the intracanal medication used: OZ-PG: ozonized propylene glycol; CH/CPMC: calcium hydroxide/camphorated paramonochlorophenol; OZ-PG/CH ozonized PG/CH; PC: positive control group (no medication); and NC: negative control group (no contamination). The samples were collected after 7 days (post-medication) and 14 days (final). Bacterial growth was checked by counting the colony-forming units (CFU). OZ-PG and CH/CPMC reduced significantly the CFU counts compared with PC in the post-medication and final samples, with no statistically significant differences among them. On the other hand, OZ-PG/CH did not reduce significantly the number of bacteria compared with PC. In conclusion, among the evaluated medications OZ-PG and CH/CPMC were the most effective against E. faecalis.

Ex-vivo Effect of Intracanal Medications Based on Ozone and Calcium Hydroxide in Root Canals Contaminated with Enterococcus faecalis

This ex vivo study evaluated the antibacterial effect of intracanal medications in root canals contaminated with Enterococcus faecalis. Fifty single-rooted human teeth were contaminated with E. faecalis (ATCC 29212) and incubated at 37°C for 21 days. The specimens were randomly divided into 5 groups according to the intracanal medication used: OZ-PG: ozonized propylene glycol; CH/CPMC: calcium hydroxide/camphorated paramonochlorophenol; OZ-PG/CH ozonized PG/CH; PC: positive control group (no medication); and NC: negative control group (no contamination). The samples were collected after 7 days (post-medication) and 14 days (final). Bacterial growth was checked by counting the colony-forming units (CFU). OZ-PG and CH/CPMC reduced significantly the CFU counts compared with PC in the post-medication and final samples, with no statistically significant differences among them. On the other hand, OZ-PG/CH did not reduce significantly the number of bacteria compared with PC. In conclusion, among the evaluated medications OZ-PG and CH/CPMC were the most effective against E. faecalis.

Resumo Este estudo ex vivo avaliou o efeito antibacteriano de medicações intracanal em canais radiculares contaminados com Enterococcus faecalis. Cinquenta dentes humanos unirradiculares foram contaminados com E. faecalis (ATCC 29212) e incubados a 37°C durante 21 dias. Os espécimes foram aleatoriamente divididos em diferentes grupos de acordo com a medicação intracanal utilizada: PG-OZ: propilenoglicol ozonizado; HC/PMCC: hidróxido de cálcio/paramonoclorofenol canforado; PG-OZ/CH; CP: controle positivo (sem medicação); e CN: controle negativo (sem contaminação). As amostras foram coletadas após 7 dias (pós-medição) e 14 dias (final). O crescimento bacteriano foi verificado através da contagem das unidades formadoras de colônias (UFC). PG-OZ e HC/PMCC reduziram estatisticamente o número de bactérias quando comparados com o CP nas amostras pós-medição e final, sem diferenças estatísticas entre si. Por outro lado, PG-OZ/HC não reduziu significativamente o número de bactérias em comparação com o CP. Em conclusão, entre as medicações avaliadas, PG-OZ e HC/PMCC foram as mais eficazes contra E. faecalis. .

Effect of the root canal final rinse protocols on the debris and smear layer removal and on the push-out strength of an epoxy-based sealer.

The aim of the present study was to evaluate the efficacy of QMiX, SmearClear, and 17% EDTA for the debris and smear layer removal from the root canal and its effects on the push-out bond strength of an epoxy-based sealer by scanning electron microscopy (SEM). Forty extracted human canines (n = 10) were assigned to the following final rinse protocols: G1-distilled water (control), G2-17% EDTA, G3-SmearClear, and G4-QMiX. The specimens were submitted to a SEM analysis to evaluate the presence of debris and smear layer, respectively, in the apical or cervical segments. In sequence, forty extracted human maxillary canines with the root canals instrumented were divided into four groups (n = 10) similar to the SEM analysis study. After the filling with AH Plus, the roots were transversally sectioned to obtain dentinal slices. The specimens were submitted to a push-out bond strength test using an electromechanical testing machine. The statistical analysis for the SEM and push-out bond strength studies were performed using the Kruskal-Wallis and Dunn tests (α = 5%). There was no difference among the G2, G3, and G4 efficacy in removing the debris and smear layer (P > 0.05). The efficacy of these groups was superior to the control group. The push-out bond strength values of G2, G3, and G4 were superior to the control group. The ability to remove the debris and smear layer by SmearClear and QMiX was as effective as the 17% EDTA. The final rinse with these solutions promoted similar push-out bond strength values.

Persistence of epoxy-based sealer residues in dentin treated with different chemical removal protocols.

The presence of residual endodontic sealer in the pulp chamber may cause discoloration of the dental crown and interfere with the adhesion of restorative materials. The aim of this study was to compare the efficacy of different solvents in removing residues of an epoxy resin-based sealer (AH Plus) from the dentin walls of the pulp chamber, by scanning electron microscopy (SEM). Forty-four bovine incisor dental crown fragments were treated with 17% EDTA and 2.5% NaOCl. Specimens received a coating of AH Plus and were left undisturbed for 5 min. Then, specimens were divided in four groups (n = 10) and cleaned with one of the following solutions: isopropyl alcohol, 95% ethanol, acetone solution, or amyl acetate solution. Negative controls (n = 2) did not receive AH Plus, while in positive controls (n = 2) the sealer was not removed. AH Plus removal was evaluated by SEM, and a score system was applied. Data were analyzed by Kruskal-Wallis and Dunn tests. None of the solutions tested was able to completely remove AH Plus from the dentin of the pulp chamber. Amyl acetate performed better than 95% ethanol and isopropyl alcohol (p < 0.05), but not better than acetone (p > 0.05) in removing the sealer from dentin. No significant differences were observed between acetone, 95% ethanol, and isopropyl alcohol (p > 0.05). It was concluded that amyl acetate and acetone may be good options for cleaning the pulp chamber after obturation with AH Plus.

Incomplete vertical root fracture associated with lateral compactiontechnique: a microscopic analysis / Fratura radicular vertical incompleta associada com a técnica de condensação lateral: Análise microscópica

Objective: This study evaluated the effects of root canal obturation employing lateral compaction technique and spreader load of 1.5 kg on the incidence of complete (CVRF) or incomplete vertical root fractures (IVRF). Material and Methods: Twenty-seven distal roots of extracted human mandibular molars were used. All root canals were prepared by biomechanical step-back technique and obturated by lateral compaction technique. The prepared roots were distributed into two groups: G1- experimental (n = 17)= and G2- control (n = 10). During obturation, load of 1.5 kg was applied to a size # 30 finger spreader. Pre- and post-obturation images of the coronal portion of the roots were captured by inverted digital microscopy and analyzed by one trained examiner. Data were evaluated by Fisher’s test (p < 0.05) using GrapH Pad Prism 5.0. Results: No roots exhibited CVRF. All fractures observed before and after obturation were IVRF or “other defects”. In G2 (control group), there was no increase of IVRF number. Interestingly, G1 presented an increase in the IVRF number to 70.59% in the 12 teeth out of 17 teeth studied. The statistical analysis showed that the mean of IVRF increased significantly in G1 when compared to G2 (p < 0.05). Conclusion: The application of a 1.5 kg spreader load during lateral compaction technique does not produce complete vertical root fractures, but may produce incomplete fractures or “other defects”.

Objetivo: Este estudo avaliou os efeitos da obturação dos canais radiculares, empregando a técnica de condensação lateral com uma força do espaçador de 1,5 kg, na incidência de fraturas radiculares verticais completas (FRVC) ou incompletas (FRVI). Material e Métodos: Foram usadas 27 raízes distais de dentes molares mandibulares humanosextraídos. Todas as raízes foram instrumentadas por meio da técnica clássica ápice-coroa e obturadas pela técnica de condensação lateral. Após o preparo biomecânico, as raízes foram distribuídas em 2 grupos: G1- experimental (n = 17) e G2- controle (n = 10). Durante a obturação, uma força de 1,5 kg foi aplicada ao espaçador digital # 30. As imagens pré- e pós-obturação da superfície coronal das raízes foram capturadas por meio de um microscópio digital invertido e analisadas por um examinador treinado. Os dados obtidos foram avaliados por meio do teste de Fisher (p < 0,05) usando o programa GrapH Pad Prism 5.0. Resultados: Não foram detectadas FRVC. Todas as fraturas observadas antes e após a obturação foram FRVI ou “outros defeitos”. No G2 (grupo controle), não houve um aumento no número de FRVI. Curiosamente, G1 apresentou um aumento das FRVI em 70,59% (12/17 raízes). A análise estatística mostrou que a média de FRVI aumentou significativamente no G1 quando comparado ao G2 (p < 0,05). Conclusão: A aplicação de uma força de 1,5 kg ao espaçador durante a realização da técnica de condensação lateral não produz fraturas radiculares verticais completas, mas pode produzir fraturas incompletas ou “outros defeitos”.