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A continuous search for bioactive materials capable of supporting the replacement of damaged pulp tissue, with effective sealing potential and biocompatibility, has represented the attention of studies over the last decades. This study involves a narrative review of the literature developed by searching representative research in PUBMED/MEDLINE and searches in textbooks associated with the mechanism of action of bioactive materials (calcium hydroxide, mineral trioxide aggregate (MTA), and calcium silicate cements). The reflective analysis of the particularities of the chemical elements of these materials, considering the tissue and antibacterial mechanism of action, allows a better understanding of the characteristics and similarities in their tissue responses. Calcium hydroxide paste remains the antibacterial substance of choice as intracanal dressing for the treatment of root canal system infections. Calcium silicate cements, including MTA, show a favorable biological response with the stimulation of mineralized tissue deposition in sealed areas when in contact with connective tissue. This is due to the similarity between the chemical elements, especially ionic dissociation, the potential stimulation of enzymes in tissues, and the contribution towards an alkaline environment due to the pH of these materials. The behavior of bioactive materials, especially MTA and the new calcium silicate cements in the biological sealing activity, has been shown to be effective. Contemporary endodontics has access to bioactive materials with similar properties, which can stimulate a biological seal in lateral and furcation root perforations, root-end fillings and root fillings, pulp capping, pulpotomy, apexification, and regenerative endodontic procedures, in addition to other clinical conditions. Resumo Uma busca contínua de materiais bioativos com capacidade de substituir o tecido pulpar danificado, com efetiva capacidade de selamento e biocompatibilidade, tem representado a atenção e foco de muitos estudos ao longo das últimas décadas. Este estudo envolve uma revisão narrativa da literatura desenvolvida por meio de pesquisas representativas encontradas no PUBMED/MEDLINE e pesquisas em livros didáticos associadas ao mecanismo de ação de materiais bioativos (hidróxido de cálcio, agregado de trióxido mineral (MTA) e cimentos de silicato de cálcio). A presente análise reflexiva das particularidades dos elementos químicos destes materiais bioativos, considerando o mecanismo de ação tecidual e antibacteriano, possibilita um melhor entendimento das características e similaridades no comportamento tecidual. A pasta de hidróxido de cálcio continua sendo a substância antibacteriana de escolha como medicação intracanal para o tratamento das infecções do sistema de canais radiculares. Este fato se deve a disponibilidade química de íons cálcio e hidroxila do hidróxido de cálcio aos tecidos, e a inibição enzimática bacteriana. Os cimentos de silicato de cálcio, dentre os quais inclui o MTA, apresentam uma resposta biológica favorável ao estímulo à deposição de tecido mineralizado nas áreas seladas e em contato com tecido conjuntivo. Este fato é decorrente da similaridade entre os elementos químicos, em especial devido a dissociação iônica, ao potencial estímulo de enzimas teciduais, e a contribuição com um meio alcalino decorrente do pH destes materiais. O comportamento dos materiais bioativos, em especial o MTA e os novos cimentos de silicato de cálcio na atividade de selamento biológico mostraram efetivos. A endodontia contemporânea atualmente conta com o potencial de materiais bioativos com propriedades análogas capaz de estimular o selamento biológico em perfurações radiculares laterais e de furca, em obturações radiculares, capeamento pulpar, pulpotomia, apicificação e procedimentos endodônticos regenerativos, além de outras condições clínicas.

This study compared the preparation of long oval-shaped root canals using WaveOne Gold and XP-endo Shaper systems, both supplemented or not with manual instrumentation. Twenty-four long oval-shaped canals of mandibular incisors were distributed into two groups according to the instrumentation: WaveOne Gold Primary or XP-endo Shaper systems. All root canals were manually instrumented with a size 25 K-file after automated preparation. The specimens were scanned by using a micro-CT device (17.42 µm) before and after automated preparation and manual instrumentation. The increased surface of the root canal and the percentage of untouched areas were assessed. Both WaveOne Gold and XP-endo Shaper systems increased the root canal surface and had similar untouched areas (p>0.05). Supplementary instrumentation increased the surface of the root canal and decreased the untouched walls (p0,05). A instrumentação complementar aumentou a superfície do canal radicular e diminuiu o percentual de áreas intocadas (p

Culture-independent molecular studies have shown a broad spectrum of bacterial taxa that persist after chemomechanical procedures (CMP). Therefore, this study systematically reviewed these reports to explore the prevalence of bacteria in post-instrumentation samples of root canals from permanent teeth, especially of as-yet-uncultivated/difficult-to-culture bacteria.Electronic databases were searched from 2007 to January 2021. Clinical studies using culture-independent molecular methods to identify species-level taxa before and after CMP were included. Studies were critically appraised using the Joanna Briggs Institute Prevalence Critical Appraisal Checklist and the funnel plot analysis. The meta-analysis was performed on the prevalence of as-yet-uncultivated/difficult-to-culture bacterial taxa using RStudio.A total of 3781 titles were screened, but only 20 studies were included. The most frequent species in post-instrumentation samples were Streptococcus spp., Leptotrichia buccalis, Fusobacterium nucleatum, and Capnocytophaga ochracea. The detection frequency of some species increased after CMP, including mainly Firmicutes members such as streptococci, Enterococcus faecium, Selenomonas noxia, and Solobacterium moorei. The prevalence (confidence interval) of difficult-to-culture species was as follows: Dialister invisus, 17% (7%-29%); Solobacterium moorei, 14% (8%-23%); Bacteroidaceae [G-1] bacterium HMT 272, 13% (5%-23%); and Filifactor alocis, 11% (3%-23%).The prevalence of as-yet-uncultivated/difficult-to-culture bacterial taxa in post-instrumentation samples was low. The persistent species belonged mainly to the phylum Firmicutes, and streptococci were the major members. Future larger clinical studies on the composition of the whole bacterial community that persist after CMP are still necessary for a better understanding of bacterial interactions and their clinical significance in the treatment outcome.

The aim of this study was to use micro-computed tomography (CT) analysis to evaluate the efficiency of the XP-endo finisher (XPF) and passive ultrasonic irrigation (PUI), alone or in combination, in reducing accumulated hard tissue debris (AHTD) in the mesial canals of mandibular molars. The teeth were micro-CT scanned preoperatively (S1), after instrumentation (S2), after final irrigation (S3), and after a supplementary activation (S4). The mesial roots were prepared with BT Race sequence to apical size 35/.04 and divided in two groups according to the final irrigation method and the sequential supplementary activation (PUI + XPF group, n = 12; XPF + PUI group, n = 12). The data of percentages of reduction of AHDT after the first irrigation and supplementary activation were statistically analyzed (RM ANOVA). In the apical third, XPF reduced the percentage of remaining AHTD (66.49%) more significantly than the PUI (35.27%) (P < 0.05). The supplementary activation promoted a statistically significant reduction of AHTD in the apical-thirds of both groups (P < 0.05). In the XPF group the middle (90.85%) and apical (80.02%) thirds were affected by the supplementary activation with ultrasonic irrigation (P < 0.05). Both PUI and XPF were efficient in the reduction of AHTD, but in the apical third XPF was more effective. The supplementary activation with both systems reduced the AHTD significantly. The order of application of irrigation systems influences the reduction of accumulated AHTD and the use of XPF followed by PUI proved to be more efficient.

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.

Introduction: To evaluate the influence of different kinematics on the efficiency and safety of an engine-driven file for glide path preparation in second mesiobuccal canals (MB2) of maxillary molars. In addition, the torsional resistance of the file was assessed after use. Methodology: Thirty-six maxillary first and second molars with two canals in the mesiobuccal root were selected and the anatomy of the canals was verified by micro-CT. The teeth were divided into 4 groups (n = 9) according to the kinematics used for glide path preparation: continuous rotation (CR), 30°/150° reciprocation (REC 30°/150°), 30°/90° reciprocation (REC 30°/90°), and 90° optimum glide path motion (OGP 90°). The duration of the procedure, number of canals in which the file reached the full working length (RFWL), canal volume before and after the procedure, rate of file fracture, and file torsional strength after use were evaluated. The ANOVA and Tukey tests or Kruskal-Wallis and Dunn tests were used for statistical analysis. Results No significant differences among the groups were found for procedure duration, success at reaching the FWL, distance from the file to apex, and number of fractured files (P > 0.05). The CR group showed a significant decrease in rotation angle compared with REC 90° and OGP 90° groups (P 0.05). Conclusion The type of kinematics used did not affect the efficiency, success rate, and shaping ability of the file during glide path preparation. CR seems to induce more torsional stress than the other kinematics. Clinical Relevance: The glide path preparation of narrow canals such as the MB2 is difficult and accidents such as file fracture may occur. This study showed that reciprocation with different file angulations can be safer during this challenging stage.

Objetivo: O presente estudo usou micro-CT para avaliar a quantidade de material obturador remanescente em canais radiculares curvos que tinham sido obturados com cimento Endosequence BC/Cpoint ou com cimento AH/ guta-percha, depois do retratamento utilizando instrumentos rotatórios ou reciprocantes. Métodos: Sessenta canais mesiovestibulares de molares superiores foram instrumentados até MTwo #35.04. As amostras foram randomicamente alocadas em quatro grupos (n=15): os canais do G1 e G2 foram obturados com AH/guta-percha, e os canais do G3 e G4 foram obturados com BC/Cpoint. O material obturador foi removido usando instrumentos rotatórios ou reciprocantes – G1 e G3: R25 Reciproc + reinstrumentação com R40; e G2 e G4: Sistema ProTaper Universal Retratamento + reinstrumentação com MTwo 40.06. Micro-CTs foram usadas para medir a quantidade de material obturador remanescente (mm3 ) para o canal inteiro e para cada terço, em dois momentos: 1) após a remoção do material obturador; e 2) após a reinstrumentação. Resultados: Após a remoção do material obturador, BC/CPoint permaneceu mais dentro do canal do que AH/guta-percha quando o canal inteiro (29,92% x 19,25%, p=0,0290) e o terço apical foram analisados. Após a reinstrumentação, BC/CPoint permaneceu mais do que AH/guta-percha somente no terço apical. Protocolos de tratamento com instrumentos rotatórios ou reciprocantes removeram material obturador sem diferença para AH/guta-percha (G1 e G2: p> 0,05) e BC/CPoint (G3 e G4: p> 0,05). Conclusões: BC/Cpoint é mais difícil de ser removido de canais radiculares curvos do que AH/guta-percha. Instrumentos rotatórios e reciprocantes têm habilidade similar na remoção de material obturador.

The aim of this study was to compare, using micro-computed tomographic imaging, the preparation of mesial canals of mandibular molars with the Reciproc (VDW GmbH, Munich, Germany) and XP-endo Shaper (FKG, La Chaux-de-Fonds, Switzerland) systems, evaluating changes in dentin and canal volume, the percentage of untouched walls, the volume of accumulated hard tissue debris, and root canal deviation in the apical third.Twenty-four mandibular molars with 2 mesial root canals and a single foramen were anatomically paired and divided into 2 experimental groups (n = 12) according to the system used. The specimens were scanned before and after preparation with the SkyScan 1176 microtomographic scanner (Bruker-microCT, Kontich, Belgium) at a resolution of 17.42 μm. The resulting data were statistically compared at a significance level of 5% using the Student t test and the Mann-Whitney test.A significant difference was observed in the untouched surface area for the total canal and the cervical and middle thirds, with the lowest untouched surface area in the XP-endo Shaper group (P.05). The volume of accumulated hard tissue debris was significantly higher in the Reciproc group in the total canal as well as in the middle and apical thirds. There was no significant difference between the groups regarding the volume of dentin removed or the increase in canal volume and surface area (P.05).The XP-endo Shaper touched more walls and left less accumulated hard tissue debris in the root canal system than the Reciproc group. Although the XP-endo Shaper showed superior results, neither system was able to fully prepare the root canal.

The outcome of root canal obturation might be affected by the chemical components of the chosen filling materials. Niobium phosphate glass-based gutta-percha (GNB) was proposed as a biomaterial-based obturation point. This study aimed to investigate the cytotoxic and cell modulation effects of GNB points on human periodontal ligament fibroblasts (PDLFs) in vitro.Human PDLFs were cultured for the assays. Extracts of regular gutta-percha (GP) points and GNB were obtained, serially diluted (1:5, 1:10, and 1:25), and used to stimulate PDLFs. A cell viability assay was performed using alamarBlue reagent (Molecular Probes, Waltham, MA), and reverse transcription quantitative polymerase chain reaction was used to assess the gene expression for collagen type I and cementum protein 1. One-way analysis of variance followed by the Tukey post hoc test was performed (P.05).Regular GP reduced cell viability only in pure extracts, whereas GNB exhibited cytotoxicity to PDLFs in pure extracts as well as 1/5 and 1/10 dilutions. The gene expression of collagen type I was down-regulated only in the GNB group (P.05). The expression of cementum protein 1 remained unaltered by both tested materials.The addition of niobium phosphate glass to GP points increased cytotoxicity, affecting PDLF viability and partially disturbing physiological cell function.

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

To evaluate the influence of different kinematics on the efficiency and safety of an engine-driven file for glide path preparation in second mesiobuccal canals (MB2) of maxillary molars. In addition, the torsional resistance of the file was assessed after use.Thirty-six maxillary first and second molars with two canals in the mesiobuccal root were selected and the anatomy of the canals was verified by micro-CT. The teeth were divided into 4 groups (n = 9) according to the kinematics used for glide path preparation: continuous rotation (CR), 30°/150° reciprocation (REC 30°/150°), 30°/90° reciprocation (REC 30°/90°), and 90° optimum glide path motion (OGP 90°). The duration of the procedure, number of canals in which the file reached the full working length (RFWL), canal volume before and after the procedure, rate of file fracture, and file torsional strength after use were evaluated. The ANOVA and Tukey tests or Kruskal-Wallis and Dunn tests were used for statistical analysis.No significant differences among the groups were found for procedure duration, success at reaching the FWL, distance from the file to apex, and number of fractured files (P 0.05). The CR group showed a significant decrease in rotation angle compared with REC 90° and OGP 90° groups (P 0.05). There was no significant difference in canal volume among the groups (P 0.05).The type of kinematics used did not affect the efficiency, success rate, and shaping ability of the file during glide path preparation. CR seems to induce more torsional stress than the other kinematics.The glide path preparation of narrow canals such as the MB2 is difficult and accidents such as file fracture may occur. This study showed that reciprocation with different file angulations can be safer during this challenging stage.

This study evaluated the apical sealing ability and bioactivity of an experimental gutta-percha containing niobium phosphate bioglass. Thirty-six human premolars were endodontically prepared and divided into three groups: GPC—filling with conventional gutta-percha; GBC—filling with bioceramic gutta-percha (EndoSequence BC); GNB—filling with experimental gutta-percha containing niobophosphate. Teeth were stored in tubes containing 2 mL of simulated body fluid (SBF) solution in an oven for 30 days. Then, the samples were immersed in lanthanum nitrate solution and analyzed for apical nanoleakage (NI) with a scanning electron microscope (SEM/EDS) and transmission electron microscope (TEM). Gutta-percha specimens were immersed for 28 days (SBF) and analyzed in SEM/EDS and X-ray diffraction (XRD) to assess bioactivity. NI data originated from the SEM/EDS were analyzed using the Kruskal–Wallis test (α = 5%). NI data originated from TEM and bioactivity were descriptively reported. Statistical analysis did not detect a significant difference between groups (p = 0.13) for NI. In the bioactivity analysis, an abundant layer of hydroxyapatite was identified only in the surface of the GNB group samples. The gutta-percha containing niobophosphate bioglass promoted an apical sealing similar to EndoSequence BC, in addition to demonstrating bioactivity through the deposition of hydroxyapatite on the surface of the material after immersion in SBF.

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.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 p0.05.Anterior teeth, maxillary premolars, and molars presented better results than mandibular premolars and molars (p0.05). 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%).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.

El éxito de los procedimientos de endodoncia regenerativa depende de la descontaminación del espacio endodóntico, la presencia de células mesenquimales indiferenciadas, la liberación de factores de crecimiento que actúan como moléculas señalizadoras para la atracción, proliferación y diferenciación celular; y de la presencia de un “scaffold”, que brinde soporte a la organización y vascularización del tejido recién formado. Objetivo. Analizar soluciones quelantes específicas de calcio EGTA, Ácido Cítrico y EDTA en la liberación de factores de crecimiento (BMPR1, BMPR2 y TGFBR1) presentes en la dentina como la adhesión célular. Materiales y Métodos. Se obtuvieron discos de dentina de premolares y terceros molares humanos, después de la imnersión por 1 minuto con EDTA, EGTA y Ácido Cítrico, se sembraron las células. La adhesión celular se evaluó a las 48 horas usando MEV. La expresión génica se determinó a los 7 y 21 días de cultivo celular. El análisis estadístico fue ANOVA seguido de Tukey, con un nivel de significancia del 5%. Resultados. A los 21 días, el tratamiento con EGTA aumento significativamente BMPR1 en comparación con PBS. Ninguna condición experimental alteró la expresión de BMPR2. La expresión de TGBR1 a los 21 días aumentó significativamente al tratamiento con EGTA. Aunque no hubo una distribución uniforme de células a lo largo de los discos, se observó adhesión celular en todos los grupos experimentales. Conclusiones. El tipo de solución desmineralizante interfiere con la cantidad liberada de factores de crecimiento BMPR1 y TGFBR1, de la dentina humana, y no interfiere en la adhesión celular.

Photobiomodulation (PBM) therapy is based on the use of specific light parameters to promote tissue repair. Although demonstrated in different cell models and tissues, the mechanism by which photobiomodulation operates is not well understood. Previous studies suggested that the cell proliferation enhancement triggered by red and near-infrared PBM involves the activation of the mitochondrial respiratory chain enzyme cytochrome c oxidase (CCO). It was suggested that light in this range would displace inhibitory nitric oxide bound to CCO. To test this mechanism, we took advantage of cell lines lacking CCO, including a mouse line knockout for Cox10 (a gene required for the synthesis of heme a, the prosthetic group of CCO) and a human cell line with an mtDNA mutation in the tRNA Lysine gene, leading to mitochondrial protein synthesis impairment and the lack of three critical CCO subunits. In both models we showed the complete absence of assembled CCO. PBM (660 nm) was applied to these proliferating cells using various parameters. In most of the conditions tested, increased cell proliferation was associated with PBM in both control and CCO negative cells, demonstrating that CCO is not required for PBM enhancement of cellular proliferation. Additional experiments showed that PBM increased both ATP levels and citrate synthase activity and levels. These results showed that although metabolic changes are associated with PBM, CCO is not required for its cell proliferation enhancing effect.

Background The appearance of high-density root obturating materials, such as gutta-percha and intracanal posts, on cone-beam computed tomography (CBCT) scans is substantially different from that seen in the specimen. This study evaluated the effectiveness of different CBCT software in the reduction of blooming artifacts when examining teeth with intracanal posts. Method The sample included 42 human single-rooted teeth with two types of posts: G1 – low-fusion alloy posts; G2 – gold alloy posts. CBCT scans were obtained using two scanners, PreXion 3D Elite® and Carestream 9000C 3D®. First, the posts were measured using a digital micrometer (standard reference, control). Post diameters were determined using the Blooming Artifact Reduction (BAR) tool of the e-Vol DX software and of the PreXion3D Image Analysis System. Statistical data were evaluated using the van Der Waerden nonparametric analysis of variance and, after that, normalized data were analyzed using the Tukey test. The level of significance was set at α = 5 %. Results There were no significant differences (p > 0.05) between the diameters of intracanal posts on the CT scans when the e-Vol DX was used, or when these results were compared with those obtained using a micrometer. There were significant differences in post diameters determined using the PreXion3D Image Analysis System when compared with the e-Vol DX and the micrometer values (p Conclusions The use of the e-Vol DX BAR filter eliminated blooming artifacts. There were no dimensional changes in the CBCT images of the low-fusion and gold alloy intracanal posts using the e-Vol DX BAR filter.

Procedimentos clínicos complementares realizados após o preparo químico-cirúrgico de canais radiculares visam potencializar a limpeza e desinfecção após a fase de preparo. O objetivo deste trabalho foi avaliar, por métodos moleculares baseados em rDNA e rRNA, a eficácia antimicrobiana de procedimentos complementares de primeira e de segunda sessão, realizados após o PQC em dentes com periodontite apical. Baseado em estudo piloto prévio, amostras microbiológicas dos canais radiculares de 20 dentes unirradiculares com periodontite apical foram coletadas na primeira sessão clínica: após a cirurgia de acesso (S1), após o PQC realizado com Sistema Reciproc e NaOCl 2,5% (S2), após a utilização do instrumento XP-endo Finisher (S3a), e após a ativação ultrassônica (S3b). Na segunda sessão clínica as amostras foram coletadas após medicação intracanal entre sessões por 14 dias (S4), e após o repreparo dos canais na segunda sessão de tratamento (S5). As amostras foram submetidas à extração de DNA e RNA. O RNA foi submetido à reação de transcrição reversa (RT-PCR) para confecção da fita dupla de DNA complementar (cDNA). DNA e cDNA foram submetidos a reações de qPCR, com iniciadores universais para a região 16S rRNA do domínio Bacteria. A atividade metabólica das bactérias foi verificada através da relação entre os níveis de rRNA e rDNA das amostras baseados nos dados dos ensaios de qPCR. Os dados foram analisados pelo teste de Wilcoxon para amostras pareadas (p < 0,05). Todas amostras S1 foram positivas para bactérias (mediana: 1,79 x 105 cópias de rDNA). Doze canais (60%) permaneceram infectados em S2, com uma redução significativa de rDNA (mediana: 7,58 x 103; P = 0,0001). Em S3a e S3b, o número de canais infectados reduziu para 11 (55%) e 10 (50%), respectivamente, e aumentou para 14 (70%) em S4; porém não houve diferenças significativas entre os níveis de rDNA bacteriano quando essas amostras foram comparadas às amostras S2 ou comparadas entre si (P > 0,05). A prevalência de canais infectados voltou a cair em S5 para 6 (30%) e o número cópias de rDNA bacteriano detectado reduziu de maneira significativa quando comparado às amostras S4 (p = 0,0061). Nas amostras positivas para os 2 métodos, os níveis de rRNA foram significativamente maiores do que os níveis de rDNA nas amostras S1 (p = 0,0007) e S4 (p = 0,0499), indicando um alto metabolismo bacteriano. A relação dos níveis de rRNA e de rDNA revelou uma redução do metabolismo de bactérias totais em S2, S3a e S3b e um aumento significativo do metabolismo bacteriano em S4 (p = 0,0173) quando comparado a S3b. Concluiu-se que: o PQC promoveu redução dos níveis e da atividade metabólica de bactérias nos canais radiculares; o uso do instrumento XP-endo Finisher e ativação ultrassônica não contribuiu para uma desinfecção adicional na primeira sessão; após o uso de Ca(OH)2 como medicação intracanal, houve um aumento no metabolismo de bactérias persistentes; o repreparo dos canais radiculares após medicação intracanal, na segunda sessão, promoveu maior desinfecção do que os procedimentos realizados na primeira sessão do tratamento de dentes com periodontite apical. Supplementary procedures performed after the chemical-surgical preparation of root canals aim to enhance cleaning and disinfection in endodontic treatment. The objective of this clinical study was to evaluate using molecular microbiological techniques based on rDNA and rRNA, the antimicrobial efficacy of supplementary disinfection procedures performed in multiple sessions after the chemical-surgical preparation in teeth with apical periodontitis. Based on a previous pilot study, microbiological samples of the root canals of 20 unirradicular teeth with apical periodontitis were taken after the access surgery (S1), after the chemical-surgical preparation using Reciproc and 2,5% NaOCl (S2) after the XP-endo Finisher (S3a), after ultrasonic activation (S3b), after intracanal medication for 14 days (S4), and after re-preparation of the root canals in the second treatment appointment (S5). The samples were submitted to DNA and RNA extraction. The RNA was subjected to the reverse transcription reaction (RT-PCR) to make the complementary DNA double strand (cDNA). The effect of endodontic procedures on bacterial reduction was determined by rDNA-based qPCR using universal primers for the 16S rRNA region of the Bacteria domain. The metabolic activity of the bacteria was assessed by the rRNA/rDNA ratio based on qPCR assay data. Data were analyzed by the Wilcoxon signed-rank test (P < 0.05). All S1 samples were positive for bacteria (median 1.79 x 105 rDNA copies). Twelve root canals (60%) remained infected in S2, with a significant reduction of rDNA (median: 7.58 x 103; P = 0.0001). In S3a and S3b, the number of infected teeth decreased to 11 (55%) and 10 (50%), respectively, and increased to 14 (70%) in S4; however there were no significant differences between bacterial rDNA levels when these samples were compared to the S2 samples or compared to each other (P> 0.05). The prevalence of infected canals dropped back to 6 (30%) in S5 and the number of bacterial rDNA detected significantly reduced when compared to S4 samples (p = 0.0061). In samples with positive reactions for both methods, rRNA levels were significantly higher than the rDNA levels in S1 (p = 0.0007) and S4 (p = 0.0499), indicating a high metabolic activity of bacteria. The results of the rRNA/rDNA ratio revealed a reduction in the metabolism of total bacteria in S2, S3a and S3b and a significant increase in metabolic activity of bacteria in S4 (p = 0.0173) when compared to S3b. It was concluded that: PQC promoted reduction of the levels and metabolic activity of bacteria in the root canals; the use of XP-endo Finisher plus ultrasonic activation did not contribute to an additional disinfection in the first session; after the use of Ca(OH)2 as intracanal medication, there was an increase in the metabolismo of persistente bacteria; the repreparation of the root canals in the second session after the use of intracanal medication, promoted greater disinfection than the procedures performed in the first session of the treatment of teeth with apical periodontitis.

Because active cells present higher abundance of ribosomal RNA (rRNA) than rDNA (rRNA genes), data obtained with rDNA-based quantitative polymerase chain reaction (qPCR) and rRNA-based qPCR (RT-qPCR) were correlated to search for active bacteria after chemomechanical procedures (CMP). In addition, the ability of both assays to detect bacteria in endodontic samples was evaluated.Samples were taken from 40 teeth with primary endodontic infections before (S1) and after CMP (S2). DNA and cDNA (synthetized from RNA) were used as templates for qPCR using universal primers for bacteria and species-specific primers for Bacteroidaceae sp. HOT-272, Cutibacterium acnes, Selenomonas spp., and Enterococcus faecalis.After CMP, there was a drastic reduction in the number of total bacteria, Selenomonas spp., and E. faecalis, whereas no significant difference was observed for the levels of Bacteroidaceae sp. HOT-272 and C. acnes. The concentration of rRNA copies in S2 samples was significantly higher than the corresponding levels of rDNA for assays targeting total bacteria, Bacteroidaceae sp. HOT-272, and C. acnes (P .05), indicating persistence of active bacteria. The rDNA-based qPCR presented low sensitivity and high specificity when compared with RT-qPCR. For most assays, samples positive for rDNA were also positive for rRNA (positive predictive value = 100%).CMP was effective in reducing levels but not the metabolic activity of total bacteria. Bacteroidaceae sp. HOT-272 and C. acnes were active members of the persistent community. Although less sensitive than RT-qPCR, most rDNA-based qPCR assays had a low risk of providing false-positive results in postinstrumentation samples.

New tools for activating endodontic irrigants have evolved, yet their impact on root canal disinfection, in comparison to the passive placing of an inter-visit medication, have not yet been fully elucidated. The use of DNA- and rRNA-based methods may cast some new light on this issue, as they allow a comparison to be made between microbial presence and activity. Therefore, the aim of this single-arm intervention trial is to evaluate the antibacterial effect of endodontic procedures using both molecular methods. Root canal samples were obtained from 20 patients with asymptomatic apical periodontitis after each treatment step: access cavity, chemo-mechanical preparation, adjunctive procedures (XP-endo Finisher file and passive ultrasonic irrigation), calcium hydroxide medication, and 2nd-visit root canal preparation. DNA and cDNA from the samples were subjected to quantitative polymerase chain reaction with universal primers for the bacterial 16S rRNA gene. Chemo-mechanical preparation promoted a drastic reduction in bacterial levels and activity, whereas the adjunctive procedures did not make a significant contribution to further disinfection. At the 2nd visit, bacteria were active after the use of calcium hydroxide medication, however, they were significantly reduced after a 2nd-visit preparation. Consequently, the lowest bacterial levels were found at the end of the treatment. This clinical trial, which used an rRNA and rDNA combined approach, confirmed previous studies showing that root canal preparation represents the main strategy for root canal disinfection.

Objetivo: Este trabalho tem por objetivo de relatar um caso clínico diagnosticado com periodontite apical assintomática na clínica do curso de Especialização em Endodontia na Universidade São Paulo abordando as indicações e técnicas realizadas, assim como os aspectos clínicos e radiográficos. As indicações para a realização de retratamento seletivo incluem casos em que o tratamento foi realizado há mais de 1 ano, dentes com restaurações coronais satisfatórias e nenhuma exposição direta da obturação do canal radicular à cavidade oral, ausência de doença periodontal, dentes multirradiculares com rarefações ósseas periapicais em apenas uma raiz, sendo confirmada pela análise de Tomografia Computadorizada de Feixe Cônico (TCFC). Relato de Caso: Paciente em questão procurou a clínica de especialização da Fundecto-USP (FFO) para retratamento endodôntico do dente 36. Na avaliação tomográfica, constatou-se a localização do canal DL não localizado e não tratado anteriormente. Foi realizado o retratamento apenas da raiz cujo canal não havia sido localizado, e que apresentava rarefação óssea periapical. Considerações finais: O retratamento seletivo de raízes com periodontite apical, pode ser mais uma forma de tratamento conservador viável em endodontia quando bem indicado em casos onde não há exposição do material obturador e o retratamento de todas as raízes, pode causar o risco de enfraquecimento da estrutura dental e perda do dente.

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.This study aims to evaluateNineteen 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.Data were statistically analyzed using Fisher's exact test and Kruskal-Wallis test.The different heat treatments and different diameters did not influence the precision of the EAL (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.

Introduction The objective of this study was to compare the methods of micro–computed tomography (micro-CT) and cross-sectioning followed by stereomicroscopy in assessing dentinal defects after instrumentation with different mechanized systems. Methods Forty mesial roots of mandibular molars were scanned and divided into 4 groups ( n = 10): Group R, Reciproc; Group PTN, ProTaper Next; Group WOG, WaveOne Gold; Group PDL, ProDesign Logic. After instrumentation, the roots were once again submitted to a micro-CT scan, and then sectioned at 3, 6, and 9 mm from the apex, and assessed for the presence of complete and incomplete dentinal defects under a stereomicroscope. The nonparametric Kruskal-Wallis, Friedman, and Wilcoxon tests were used in the statistical analysis. The study used a significance level of 5%. Results The total number of defects observed by cross-sectioning followed by stereomicroscopy was significantly higher than that observed by micro-CT, in all of the experimental groups ( P ≤ .05). All of the defects identified in the postoperative period were already present in the corresponding preoperative period. There was no significant difference among the instrumentation systems as to the median numbers of defects, for either cross-sectioning followed by stereomicroscopy or micro-CT, at all the root levels ( P > .05). In the micro-CT analysis, no significant difference was found between the median numbers of pre- and postinstrumentation defects, regardless of the instrumentation system ( P > .05). Conclusion None of the evaluated instrumentation systems led to the formation of new dentin defects. All of the defects identified in the stereomicroscopic analysis were already present before instrumentation, or were absent at both time points in the micro-CT analysis, indicating that the formation of new defects resulted from the sectioning procedure performed before stereomicroscopy and not from instrumentation.

Aim To evaluate oval root canal preparation using one or two instruments in counterclockwise or clockwise reciprocating motion. Methodology The radiographic diameter of mandibular human incisors was evaluated, and oval canals were selected (2 ≤ Diameter Ratio ≤ 4). Fifty-seven teeth were assigned to root canal preparation (n = 19): Reciproc 40 (R40) in a counterclockwise reciprocating motion; Mtwo size 40, .06 taper (M 40.06) in a clockwise reciprocating motion or Mtwo size 20, .06 taper and size 40, .06 taper (M 20/40.06) in a clockwise reciprocating motion. Mtwo instruments were coupled to an ENDO DUAL motor, turning 150° clockwise and 30° counterclockwise. Scanning was performed before and after root canal preparation using a SkyScan 1176 micro-computed tomography. Volume, percentage of debris and percentage of uninstrumented surface were analysed in the entire root canal and in each third of the canal. Data were compared using anova and Tukey's tests or Kruskal–Wallis and Dunn tests. Results The Reciproc and Mtwo systems using different kinematics were associated with a similar increase in root canal volume. Additionally, both system had similar percentage of uninstrumented surface (P > 0.05). Mtwo size 20, .06 taper and size 40, .06 taper was associated with significantly lower debris (P

Objective The rDNA-based method is unable to distinguish between alive and dead cells. Alternatively, bacterial viability can be assessed by molecular methods based on ribosomal RNA (rRNA). Therefore, this study aimed to detect viable streptococci in root canal samples using rRNA-based reverse transcription polymerase chain reaction (RT-PCR), compared to an rDNA-based PCR assay. Methodology Microbiological root canal samples were obtained from 32 teeth with primary endodontic infections before (S1) and after chemomechanical preparation (S2), and after removal of intracanal medication (S3). RNA and DNA were extracted, and complementary DNA (cDNA) was synthesized from RNA using RT reaction. cDNA and genomic DNA were subjected to PCR with primers complementary to the 16S rRNA sequences of Streptococcus spp. McNemar’s test was used to compare the detection rate of both assays (P

The aim of the present study was to assess the penetration capacity of two endodontic cements, Endosequence BC Sealer and AH Plus, in artificial lateral canals. Twenty-six two-rooted, maxillary first premolars were instrumented to size 40.06 using K3 files. In each root, six lateral canals of two diameters (0.06 and 0.10 mm) were created with a working length of 2, 4, and 6 mm. The specimens were randomly divided into two groups according to the endodontic cement to be used (Endosequence BC Sealer and AH Plus) and obturated by the single-cone technique. The specimens were imaged by digital periapical radiography and scores from 0 to 4 were attributed according to the degree of penetration by sealers into the lateral canals. Data were analyzed statistically by Kruskal-Wallis and Student-Newman-Keuls tests, and a significance level of p < 0.05 was adopted. No significant difference was observed between the two endodontic cements used to fill the simulated lateral canals (p > 0.05). The diameter of lateral canals only influenced the capacity of the Endosequence BC Sealer in filling the canals, and presented greater penetration in the lateral canals of diameter 0.10 mm (p < 0.05). We concluded that the bioceramic endodontic cement Endosequence BC Sealer presented similar ability as AH Plus to fill simulated lateral canals.

To evaluate the torsional properties of engine-driven pathfinding instruments manufactured from different NiTi alloys – R-Pilot (tip size 12.5;.04 taper; M-Wire) and One G (tip size 14;.03 taper; Conventional NiTi). A total of 40 NiTi instruments from engine-driven pathfinding instruments (n = 20) were used. The torsion tests followed ISO 3630-1 (1992). Three millimeters of each instrument tip was fastened to a small load cell by a lever arm linked to the axis of torsion. During the test, the torsion testing machine software measured the maximum torsional strength and angle of rotation (0) before instrument failure. The fractured surface of each instrument was assessed by scanning electron microscopy (SEM). In addition, a supplementary examination was performed to measure the cross-sectional area and the metal mass volume of each instrument 3 mm from the tip. Data were analyzed using a t-test, with significance level set at 5%. R-pilot had significantly higher torsional strength than did One G (p < 0.05). Regarding the angle of rotation to fracture, One G had higher angles than did R-Pilot (p < 0.05). The supplementary examination showed that R-Pilot had the highest cross-sectional area and volume of metal mass at 3 mm from the tip (p < 0.05). R-pilot (M-Wire NiTi alloy) had a significantly higher torsional strength and One-G (superelastic NiTi alloy) had the highest angle of rotation to fracture.

Introduction Radiation therapy (RT) of malignant tumors in the head and neck area may have damaging effects on surrounding tissues. The aim of this investigation was to evaluate the long-term effects of ionizing radiation on pulp vitality by measuring pulp oxygenation levels (%SpO 2 ) in patients with history of RT of intraoral and oropharyngeal tumors 4–6 years after treatment. Methods In an experimental group RT ( n = 90, history of RT) and a control group CON ( n = 90, no history of RT), pulp vitality was assessed by measuring %SpO 2 by using pulse oximetry and pulp sensitivity by cold thermal testing. All anterior teeth without history of endodontic therapy of the participants in group RT were measured ( n = 693), regardless of the quadrant and the irradiated area. An equal number of anterior teeth were tested in group CON. Results There was no significant difference between the %SpO 2 levels in group RT (92.7%; standard deviation, ± 1.83) and group CON (92.6%; standard deviation, ± 1.80). All teeth in RT and CON groups showed a positive response to the thermal test. All tested teeth were considered vital. Conclusions Pulp %SpO 2 was found to be within normal limits 4–6 years after RT. This suggests that RT may not have a long-term influence on pulp vitality, and reported short-term changes in pulpal microcirculation because of RT may be temporary.

Background and Aim Subjective pulp tests are not trustworthy, particularly in traumatized teeth, and may lead to inaccurate diagnosis. The use of an objective test such as pulse oximetry (PO) could be a more reliable method to properly evaluate pulp status in this condition. The aim of this study was to analyze the effectiveness of PO in determining pulp vitality in traumatized teeth based on oxygen saturation measurements (%SpO2). Subjects and methods Fifty-nine permanent teeth that had undergone lateral luxation, and which were unresponsive to a cold spray test and were free from signs of necrosis, were selected and tested with PO at 7, 30 and 60 days after trauma. Results Fifty-nine teeth were tested. At 7 days after trauma, 8 teeth had low rates of oxygenation, compared to 10 at 30 and 60 days. Low rates were defined as a saturation reading ≤77%SpO2. These teeth were assigned to the pulp necrosis (PN) group. The other 49 teeth were either considered to have healthy pulps (HP) (saturation ≥90%SpO2) or were assigned to a pulpitis (PP) group (saturation ≥78 to ≤89%SpO2). The 10 non-responsive teeth were followed up for 1 year and all exhibited indications for endodontic treatment. The other 49 teeth (HP or PP) began to show positive responses to the cold spray (after 3–9 months of follow up). No significant differences (P < 0.05) were detected between the three periods analyzed, but %SpO2 rates were significantly different (P < 0.01) between the groups (HP vs PP, HP vs PN and PP vs PN). Conclusions PO can be extremely useful for the assessment of dental pulp status in traumatized teeth, particularly when these teeth do not show signs of PN and do not respond to cold tests.

The introduction of automated instrumentation in endodontics represented a major advance in progress for this specialty, with improvements in the quality and predictability of root canal preparation and a significant reduction in procedural errors. In recent years, endodontic instruments have undergone a series of changes brought about by modifications in design, surface treatments, and thermal treatments. In addition, new movements have also been incorporated to offer greater safety and efficiency, optimizing the properties of the NiTi alloy, especially through eccentric rotary motion. An understanding of the mechanical properties of these new NiTi instruments and their effect on the clinical performance of root canal preparation is essential if dental practitioners are to select the instruments that provide optimal clinical outcomes, especially in curved or flattened canals. The objective of this literature review is to present and discuss the characteristics of the NiTi alloys used in the major instrumentation systems available in the market, as well as the influence of the metallurgical and mechanical properties of NiTi instruments and the movements that drive them, to enable more accurate and predictable planning of root canal preparation.

Aim This randomized clinical trial aimed to compare the effectiveness of ultrasonic activation with that of nonactivated irrigation on the removal of bacteria and endotoxin from root canals. Methodology Fifty patients with necrotic pulps and asymptomatic apical periodontitis were randomly allocated into two groups according to the final irrigation protocol after root canal preparation: Group UI – ultrasonic irrigation (n = 25) and Group NI – needle irrigation (n = 25). The root canals were medicated with calcium hydroxide for 14 days. Microbiological sampling was performed before (S1) and after the root canal preparation (S2), after the irrigation protocols (S3) and after the removal of the intracanal medication (S4). Total bacteria counts were determined by qPCR and the endotoxin levels by the limulus amebocyte lysate assay. Intragroup analyses were performed using the Wilcoxon test for related samples, whereas intergroup analyses were performed using the Mann–Whitney U-test (P