Noncontact 3D evaluation of surface topography of reciprocating instruments after retreatment procedures

Abstract This study evaluated the Reciproc R25 and Pro-R 25 instruments in unused condition, after one and a second use in endodontic retreatment employing a noncontact 3D light interferometer profiler, scanning electron microscopy (SEM) and cyclic fatigue tests. Twenty single-root teeth were instrumented with Reciproc R25 and filled with gutta-percha and sealer. A 3D profiler with a 20x objective using the Mx™ software was used to evaluate the cutting blade surfaces of Reciproc R25 and Pro-R 25 (n=5 per group) in unused condition, after the first and second uses in retreatment procedures. After retreatment, SEM was used to evaluate the topographic features of the used instruments. Cyclic fatigue tests were performed to compare new to used instruments. One-way ANOVA followed by Tukey test was used to compare the tested instruments before and after the first and second uses. Student t-test was used to compare the different instruments and for cyclic fatigue evaluation. No significant differences were observed in the cutting blade surfaces of Reciproc and Pro-R before and after one and two uses (p>0.05). Reciproc without use showed higher Sa and Sq when compared to Pro-R without use (p<0.05). No differences were observed between Reciproc and Pro-R after one and two uses (p>0.05). New and unused Reciproc showed longer time to fracture than Pro-R instruments (p<0.05), and only Pro-R showed differences between new and used instruments (p<0.05). Retreatment procedures with Reciproc and Pro-R did not change the surface topography of instruments. Reciproc had greater resistance to cyclic fatigue compared with Pro-R.

Resumo Este estudo avaliou os instrumentos Reciproc R25 e Pro-R 25 sem uso, após um primeiro e um segundo uso em retratamento endodôntico com perfilômetro 3D por interferometria de luz sem contato, microscópio eletrônico de varredura (MEV) e testes de fadiga cíclica. Vinte dentes unirradiculares foram instrumentados com Reciproc R25 e obturados com guta-percha e cimento endodôntico. Um perfilômetro 3D com uma objetiva 20x usando o software Mx ™ foi usado para avaliar as superfícies da lâmina de corte do Reciproc e Pro-R (n = 5 por grupo) na condição sem uso, após o primeiro e após um segundo uso em procedimentos de retratamento. Após retratamento, o MEV foi usado para avaliar as características topográficas dos instrumentos utilizados. Testes de fadiga cíclica foram realizados para comparar instrumentos novos com instrumentos usados. O teste One-way ANOVA seguido pelo teste de Tukey foi usado para comparar os instrumentos testados nos diferentes estágios. Para comparar os diferentes instrumentos e para avaliação de fadiga cílcica, foi utilizado o Student t-test. Não foram observadas diferenças estatisticamente significantes nas superfícies das lâminas de corte dos instrumentos Reciproc e Pro-R antes e após um e dois usos (p> 0,05). O Reciproc na condição sem uso apresentou maior Sa e Sq quando comparado ao Pro-R (p <0,05). Não foram observadas diferenças entre Reciproc e Pro-R após um e dois usos (p> 0,05). O Reciproc sem uso apresentou maior tempo de fratura do que os instrumentos Pro-R (p<0,05), e apenas o Pro-R apresentou diferenças entre instrumentos novos e usados (p<0,05). Os procedimentos de retratamento com Reciproc e Pro-R não alteraram a topografia da superfície dos instrumentos. Reciproc apresentou maior resistência à fadiga cíclica em comparação com o Pro-R.

A comparison of the physicochemical properties of AH Plus Jet with samples taken from the beginning, middle and final portions of the automix syringe system

Aim To evaluate physicochemical properties and semi-quantitative elemental analysis of AH Plus Jet with samples from the beginning, middle and final portions of the automix syringe system. Methodology Three experimental groups based on the source of the material used (beginning, middle and final portion) were established for each of the evaluated properties. Setting time, flow and radiopacity were evaluate following ANSI/ADA n. 57 specification. Set specimens was used in the semi-quantitative elemental analysis in an energy-dispersive X ray spectroscopy and scanning-electron microscopy (EDS/SEM). Statistical analysis was performed using one-way ANOVA followed by Tukey test (P<0.05). Results Flow, setting time, solubility and EDS/SEM tests showed no significant differences among the three portions of the automix syringe (P>0.05). Radiopacity test showed significant differences in the beginning of the syringe comparing to the middle and final portions (P<0.05). EDS/SEM analysis identified the presence of C, O, Al, Ca, Zr and W. The element Al, however, was found only in the final portion of the syringe. Conclusions The results of AH Plus Jet suggested an adequate ratio of the components, without segregation between organic and inorganic components, since the results of setting time, flow, solubility and EDS/SEM analysis presented similar values regardless of the portion of the syringe from where the sealer was taken.

Influência do pré-alargamento coronário na resistência à fadiga cíclica de instrumentos reciprocantes tratados termicamente / Influence of coronal pre-enlargement on cyclic fatigue resistance of heat-treated reciprocating instruments

Objetivo: O objetivo do presente estudo foi avaliar a influência do pré-alargamento coronário na resistência à fadiga cíclica de dois instrumentos reciprocantes tratados termicamente. Métodos: 20 instrumentos Reciproc Blue (R25 Blue) e 20 instrumentos X1 Blue (X1) foram utilizados para instrumentar blocos de resina simulando um molar superior com três canais radiculares. Os dentes foram divididos em quatro grupos (n=10), de acordo com o instrumento e com a técnica de instrumentação utilizada: grupos R25 e X1 - instrumentação com R25 Blue (25/0.08) ou X1 Blue (25/0.06), respectivamente, sem alargamento prévio; e grupos R25 ou X1 + pré-alargamento cervical - pré-alargamento com os instrumentos ProTaper Universal SX e S1 antes da instrumentação com R25 Blue ou X1. Os instrumentos foram testados com relação à fadiga cíclica utilizando-se um canal simulado de aço inoxidável com ângulo de curvatura de 86 graus e raio de curvatura de 6 mm. Os instrumentos foram acionados utilizando-se o movimento "RECIPROC ALL" do motor endodôntico (VDW) e o tempo de instrumentação até a fratura do instrumento foi contabilizado. Os resultados foram analisados pelo teste t de Student (p<0,05). Resultados: Os instrumentos X1 apresentaram maior resistência à fadiga cíclica do que R25 Blue em ambas as condições testadas (p<0,05). Não houve diferença entre os grupos com e sem pré-alargamento coronário para os instrumentos R25 Blue e X1 (p>0,05). Conclusão: O instrumento X1 Blue apresentou maior resistência à fadiga cíclica do que o Reciproc Blue. O pré-alargamento coronário não foi capaz de aumentar a resistência à fratura por fadiga cíclica dos instrumentos testados (AU).

Objective: The aim of this study was to evaluate the influence of cervical pre-flaring on the cyclic fatigue resistance of two heat-treated reciprocating instruments. Methods: 20 Reciproc Blue (R25 Blue) instruments e 20 X1 Blue File (X1) were used to instrument resin blocks simulating an upper molar with 3 root canals. The specimens were divided into four groups (n=10) according the instrument and type of instrumentation used: R25 and X1 groups: root canal preparation with R25 Blue (25/0.08) ou X1 Blue (25/0.06), without cervical pre-flaring; R25 or X1 + cervical pre-flaring- pre-flaring with ProTaper Universal SX e S1 before instrumentation with R25 Blue or X1 blue. After instrumentation the instruments were tested for cyclic fatigue using a simulated stainless steel root canal with 86 degree bending angle and 6 mm bending radius. The instruments were triggered using the "RECIPROC ALL" motion of a reciprocating endodontic motor (VDW) and the instrumentation time until instrument fracture was accounted. Results were analyzed by Students t-test (p<0.05). Results: Statistical analysis showed that the X1 Blue showed higher resistance to cyclic fatigue than the R25 Blue under both conditions tested (p<0.05). There were no differences between the groups with and without coronary pre-flaring for the R25 Blue and X1 Blue (p<0.05). Conclusion: X1 Blue showed higher resistance to cyclic fatigue than the R25 Blue. The cervical pre-flaring did not increased the resistance to cyclic fatigue fracture of the tested instruments (AU)

Acessos endodônticos: o que todo endodontista deve saber / Endodontic accesses: what every endodontist should know

Introdução: Os acessos endodônticos minimamente invasivos (AEMI) surgiram com o intuito de, por meio da preservação de estrutura dentária, manter a resistência à fratura de dentes tratados endodonticamente. A partir do primeiro estudo, em 2010, vários trabalhos foram desenvolvidos buscando entender qual a influência dos AEMI na resistência à fratura de dentes tratados endodonticamente. No entanto, interferências coronárias causadas pelos AEMI poderiam prejudicar a realização dos procedimentos subsequentes à cavidade de acesso, como a localização, instrumentação, limpeza, descontaminação e obturação dos canais radiculares. Objetivo: Com base nessa premissa, a presente revisão teve como objetivo responder algumas perguntas para que o clínico entenda quais são as principais modalidades de AEMI, os impactos da sua abordagem no tratamento endodôntico e o verdadeiro papel do tratamento endodôntico na perda dos elementos dentários. Resultados: Considerando os dados disponíveis até o presente momento, faltam evidências robustas para apoiar a alegação de que os AEMIs preservem a resistência à fratura dos elementos tratados endodonticamente melhor do que nos dentes acessados de maneira tradicional. Além disso, cavidades de acesso minimamente invasivas podem interferir em outras etapas do tratamento endodôntico, podendo torná-lo imprevisível. Conclusão: Dessa forma, pode-se concluir que há uma falta de evidências que apoiem a utilização de cavidades de acesso minimamente invasivas na prática clínica de rotina e/ou no processo de formação de alunos de graduação e pós-graduação (AU).

Introduction: Minimally invasive access cavities emerged aiming to maintain the fracture resistance of endodontically treated teeth through the preservation of dental structure. Starting with the first study in 2010, several others were developed to evaluate the influence of minimally invasive access cavities in the fracture resistance of endodontically treated teeth. However, the coronal interference caused by those access cavities could impair the subsequent procedures of root canal treatment, such as the location, instrumentation, cleaning, disinfection and filling of the root canals. Objective: Based on this premise, the aim of the present review was to answer some questions so that the clinician knows the main modalities of minimally invasive access cavities, the impacts of this approach and the real role of endodontic treatment in the tooth loss. Results: Considering the available data, there is a lack of robust evidence in literature to support the claim that the minimally invasive access cavities preserve the fracture resistance of endodontically treated teeth better than the traditional one. In addition, these access cavities can interfere in other stages of endodontic treatment, making it unpredictable. Conclusion: Thus, it can be concluded that there is a lack of evidence to support the use of minimally invasive access cavities in routine clinical practice and/or in the process of training undergraduate and graduate students (AU).

Influência da orientação das ranhuras superficiais na flexão rotativa de fios de níquel-titânio / Influence of surface grooves orientation on the cyclic fatigue resistance of NiTi wire

Objetivo: Testar a hipótese nula de que a orientação das ranhuras superficiais não influencia na vida em fadiga de fios de níquel-titânio (NiTi). Material e Métodos: Segmentos de fio de NiTi (Moreli, Sorocaba/SP, Brasil) medindo 30mm e com diâmetro de 0,40mm foram utilizados. As ranhuras foram criadas em relação à direção longitudinal, em 45 e 90 graus. O fio foi analisado sob microscopia eletrônica de varredura e a rugosidade, quantificada por interferometria. O número de ciclos para a fratura (NCF) foi determinado pelo teste de flexão rotativa. Resultados: A rugosidade entre os grupos de 45 e 90 graus apresentou diferenças estatisticamente significativas (p<0,05). O grupo sem ranhuras apresentou o maior NCF (p<0,05). O grupo com ranhuras em 45 graus apresentou maior NCF, em comparação ao grupo com 90 graus (p<0,05). Conclusões: A direção das ranhuras possui influência na vida em fadiga dos fios de NiTi. O NCF aumenta com a redução do ângulo das ranhuras em relação ao longo eixo do fio, independentemente da profundidade das ranhuras (AU).

Objective: this study tested the null hypothesis that the surface grooves orientation does not influence the NiTi wire cyclic fatigue. Material and methods: Segments of NiTi wire (Moreli, Sorocaba, Brazil) measuring 30mm and with a 0.40mm of diameter were used. Grooves were created in the longitudinal direction, at 45 degrees and 90 degrees. The wire was analyzed with SEM and the roughness was quantified by interferometry. The number of cycles until fracture (NCF) was determined by the cyclic fatigue test. Results: the roughness between 45 and 90 degrees groups presented differences (p<0.05). The group without grooves presented the highest NCF (p<0.05). The group with 45 degrees grooves presented better NCF in comparison to the group with 90 degrees (p<0.05). Conclusions: the direction of the grooves influences the fatigue life. The NCF increases with the reduction of the angle of the grooves in relation to the long axis, regardless of the depth of the grooves (AU).

Effect of passive ultrasonic irrigation on hard tissue debris removal: a systematic review and meta-analysis

Abstract: Accumulated hard tissue debris (AHTD) in root canal irregularities may negatively impact adequate root canal disinfection. In light of this, the efficacy of passive ultrasonic irrigation (PUI) to reduce AHTD has been largely studied in in vitro studies, which have adopted different analytic methods of varying accuracy to determine the extent of AHTD more correctly. Therefore, the aim of this study was to compare how well PUI and non-activated irrigation (NAI) systems perform in reducing AHTD during final irrigation protocols, based exclusively on studies whose analyses used microCT scanning. A systematic search of the studies published up to April 2020 was performed using MeSH terms and free terms, in the following databases: PubMed, Scopus, Web of Science, BVS (Lilacs and BBO) and Embase. The inclusion criteria consisted of laboratory studies that evaluated the amount of AHTD, and compared PUI with NAI protocols using microCT analysis. The risk of bias in the selected studies was assessed critically by two reviewers. A meta-analysis was performed using the RevMan software program (P<0.05), and included studies providing the standardized mean difference (SMD), using a fixed effect model, and adopting a confidence interval of 95%. In all, 3495 studies were identified, three of which met the inclusion criteria. All three were considered as having a low risk of bias. The meta-analysis comparing the ability of PUI and NAI protocols to remove hard tissue debris showed a higher percentage of AHTD reduction (P<0.01) for PUI, with a confidence interval of 1.41 [0.79, 2.02]. The heterogeneity among the studies was 82% (I2). Considering the limitations of the present study, this systematic review and meta-analysis showed that PUI was more effective than NAI in removing hard tissue debris, based exclusively on studies that used microCT scanning to provide a more precise analysis of the two techniques used. The findings presented in the present study reinforce the concept that PUI can increase residue removal and improve the cleanliness of the root canal in endodontic treatments.

Cytotoxicity, and antimicrobial and physicochemical properties of sealers incorporated with Uncaria tomentosa

Abstract This study evaluated the cytotoxicity, the antimicrobial and physicochemical properties of root canal sealers incorporated with phytotherapic Uncaria tomentosa (UT). Unmodified AH Plus (Dentsply, DeTrey, Germany) and MTA Fillapex (Angelus, Londrina, Brazil) were used as controls. UT was incorporated into AH Plus and MTA Fillapex, at concentrations of 2% and 5% of the total weight of these sealers (w/w). Flowability, setting time, and solubility were evaluated following ISO requirements. The pH values were measured at periods of 12, 24, 48 hours, and 7 days. The antimicrobial activity of the sealers against Enterococcus faecalis was analyzed by both direct contact tests in freshly prepared sealers, and after 7 days. The cytotoxicity of the samples was evaluated by the MTT assay, to check Balb/c 3T3 cell viability. The statistical analysis was performed by one-way ANOVA and Tukey's test (p < 0.05). The incorporation of UT was associated with a decrease in flow, for both sealers, an increase in AH Plus setting time, increase in MTA Fillapex pH values, and solubility (after 14 days), for both sealers (p < 0.05). Regarding the antibacterial evaluation, bacterial reduction was reported after incorporation of UT into both AH Plus and MTA Fillapex, up to 7 days after handling of the material (P<0.05). UT incorporation decreased the cytotoxic effects of both AH Plus and MTA Fillapex sealers in a way directly proportional to their respective concentrations (p < 0.05). In conclusion, UT can be added to both sealers to reduce their cytotoxicity, and improve their antibacterial effects, without compromising their original physicochemical properties.

Effects of clinical use of NiTi reciprocating instruments on cyclic and torsional resistance, and on roughness

Abstrac The aim of the present study was to evaluate the cyclic fatigue, torsional resistance and surface roughness of Reciproc R25 instruments in four different situations, namely as new instruments and as instruments tested after clinical preparation of one, two or three maxillary molars with four root canals. The total time required to perform each root canal preparation was recorded. Cyclic fatigue resistance was determined by the time to fracture using a customized testing device (n = 10 per group). The torsional test evaluated the torque and angle of rotation to failure according to ISO 3630-1 (n = 10 per group). The roughness of the working parts of new and used instruments was evaluated with a profilometer (n = 5 per group). Statistical analysis was performed using one-way ANOVA and Tukey's test. The level of significance was set at 5%. No fractures or deformations were observed after clinical use. Higher preparation time was needed during the third use of the instruments for all root canals (p < 0.05). There were no significant differences among the groups in regard to either cyclic fatigue or torsional resistance (p > 0.05). Regarding the roughness measurements, groove depth was higher on new and one- versus two- or three-maxillary-molar-prepared instruments (p < 0.05). It can be concluded that the clinical use of Reciproc instruments increased preparation time and decreased surface roughness. However, clinical use did not affect the cyclic fatigue or torsional resistance of the Reciproc instruments.

Influência do tipo de cimento endodôntico na adesão de pinos de fibra de vidro: revisão de literatura / Influence of the type of endodontic sealer on glass fiber post adhesion: literature review

Introdução: Pinos de fibra de vidro são bastante utilizados quando dentes tratados endodonticamente apresentam grande perda estrutural e necessitam de suporte para a sua reconstrução coronária. A completa adesão do pino à parede do canal radicular é fundamental para o sucesso dessa restauração. Resíduos de cimento endodôntico que permanecem nas paredes dentinárias, mesmo após o preparo para a cimentação, podem interferir negativamente na sua adesão e contribuir para o seu deslocamento. Objetivo: O objetivo da presente revisão de literatura foi avaliar o efeito de diferentes cimentos endodônticos e o tempo decorrido entre a obturação e a cimentação do pino na resistência de união entre o pino e a parede do canal radicular. Métodos: Essa revisão de literatura incluiu 21 estudos que analisaram a influência de cimentos endodônticos na adesão de pinos de fibra de vidro, entre os quais 9 acrescentaram a variável tempo na sua análise, com pinos cimentados logo após a obturação do canal radicular e dias após a obturação. Resultados: Os dentes obturados com cimentos à base de resina demonstraram maior resistência ao deslocamento dos pinos durante os testes. Parece haver uma predominância de menores valores de adesão quando os pinos são cimentados imediatamente após a obturação com cimentos contendo eugenol. Conclusões: Os tipos de cimento endodôntico e o período entre a obturação e a cimentação do pino podem afetar a força de ligação entre a parede do canal radicular e o pino de fibra de vidro (AU).

ntroduction: Glass fiber posts are widely used when endodontically treated teeth present great structural loss and require support for coronal reconstruction. Complete adhesion of the post to the root canal wall is fundamental for the success of this restoration. Endodontic sealer residues that remain on the dentin walls, even after preparation for cementation, may negatively interfere with the adhesion and contribute for post displacement. This literature review evaluated the effect of different endodontic sealers and the time between obturation and post cementation on the bond strength. Methods: This literature review included 21 studies that analyzed the influence of endodontic sealers on the adhesion of glass fiber posts, among which 9 added the variable time in their analysis. Results: Teeth filled with resin-based sealers showed higher post push-out bond strength during testing. There seems to be predominance of lower adhesion values when the posts are cemented immediately after filling with eugenol-containing sealers. Conclusions: The type of endodontic sealer and period between obturation and post cementation can affect the bond strength between root canal wall and the glass fiber post(AU).

Efeito do consumo de álcool no desenvolvimento de lesão periapical induzida em ratos: uma análise microtomográfica / The Effect of Alcohol Consumption on the Development of Periapical Lesion Induced in Rats: a Micro-CT Analysis

Objetivo: O objetivo deste estudo foi avaliar a influência do consumo crônico de álcool no aumento da destruição óssea periapical em ratos. Material e métodos: Foram selecionados 12 ratos machos da linhagem Wistar, aleatoriamente divididos nos grupos controle e álcool (n=6). Os ratos do grupo álcool foram submetidos à auto-administração de solução alcoólica contendo 25% de álcool puro. O grupo controle recebeu apenas água filtrada durante o estudo. Após as 5 semanas de adaptação do grupo álcool, todos os ratos foram anestesiados e a polpa dos seus primeiros molares inferiores esquerdos foi exposta à cavidade oral para indução da lesão periapical. Após 28 dias de exposição pulpar, os ratos foram sacrificados por sobredose de anestesia, e suas mandíbulas foram removidas e seccionadas para avaliação microtomográfica. As hemimandíbulas esquerdas foram fixadas e escaneadas no microtomógrafo SkyScan 1173 (Bruker, Kontich, Belgium). O tamanho da lesão periradicular foi medido a partir das imagens de microtomografia computadorizada (micro-CT), onde foram calculados a área de superfície e o volume da lesão. Também foram avaliadas a taxa percentual de ganho de peso e a ingestão de sólidos/líquidos dos grupos. Os dados foram estatisticamente analisados utilizando o teste t de Student (p<0,05). Resultados: Os animais do grupo controle tiveram uma maior taxa percentual de ganho de peso corporal e de ingestão tanto de sólidos como de líquidos (p<0,05). As lesões periapicais apresentaram maior volume e maior área nos animais do grupo álcool, em comparação ao grupo controle (p<0,05). Conclusão: O consumo crônico de álcool contribuiu para o aumento da destruição óssea periapical em casos de periodontite apical.

Objective: the aim of this study was to evaluate the influence of alcohol consumption on the increase of periapical bone destruction in rats. Material and Methods: the sample included 12 Wistar male rats, randomly assigned into a control group and an alcohol group (n=6). Rats in the alcohol group were submitted to self-administration of a 25% pure alcoholic solution. The control group received only filtered water throughout the study. After 5 weeks of adaptation to the alcohol dose, all animals were anesthetized and the pulps of their mandibular left first molar were exposed to the oral cavity to induce periapical lesion. Twenty-eight days after the pulp exposure, those rats were euthanized due to overdose of anesthesia and their mandibles were removed and sectioned to obtain a micro-computed tomographic (micro-CT) scan. The rats' left hemimandibles were fixed and scanned on the SkyScan 1173 (Bruker, Konitch, Belgium) microtomograph. The size of the periradicular lesions was measured from the images obtained on the micro-CT and the surface area and volume were calculated. It was also evaluated the weight gain rate and the ingestion of solid/liquid of both groups. Data were analyzed by the Student's t-test (p<0.05). Results: the control group showed higher rates of weight gain and ingested more solid and liquid than the alcohol group (p<0.05). Periapical lesions found in the alcohol group had higher volume and surface area than the ones of the control group (p<0.05). Conclusion: the chronic consumption of alcohol contributed to the increase of periapical bone destruction in cases of apical periodontitis

Avaliação da citotoxicidade in vitro de diferentes pastas endodônticas utilizadas em odontopediatria / In vitro cytotoxic effects of different endodontic pastes used in pediatric dentistry

Objetivo: O presente estudo teve como objetivo avaliar o potencial citotóxico de três diferentes pastas endodônticas em cultura celular de osteoblastos humanos. Material e Métodos: As pastas endodônticas Calen PMCC (SSWhite Artigos Dentários LTDA, Rio de Janeiro, Brasil), Feapex (Fórmula e Ação, São Paulo, Brasil) e CTZ (Lenzafarm, Belo Horizonte, Brasil) foram preparadas e eluídas em meio de cultura celular durante 24 horas em estufa a 37°C e 5% de CO2. Foram realizadas quatro diluições distintas desses meios nas concentrações 1: 1, 1: 2, 1: 4 e 1: 8. Culturas de células de Osteoblastos Humanos da linhagem Saos-2 foram expostas a estas diluições durante 24 horas. O controle negativo foi realizado expondo as células ao meio de cultura sem contato com nenhuma pasta endodôntica. A citotoxicidade desses meios foi avaliada utilizando o ensaio MTT e os resultados foram transformados em porcentagens de células viáveis em relação ao grupo controle negativo. A análise estatística foi realizada com nível de significância de 5%, utilizando ANOVA seguido do teste de Tukey. Resultados: A viabilidade celular foi significativamente alterada de acordo com o material testado (p <0,05) e sua concentração (p <0,05). Em todas as concentrações testadas, a pasta Feapex apresentou maior viabilidade celular comparada aos demais materiais (p <0,05). Embora não tenha sido observada diferença estatisticamente significante entre a pasta Calen PMCC e a pasta CTZ nas concentrações de 1: 1 e 1: 2 (p> 0,05), a pasta CTZ apresentou maior citotoxicidade nas concentrações de 1: 4 e 1: 8 (p <0,05 ). De forma geral, a citotoxicidade diminuiu com o aumento da diluição do material. Conclusão: De acordo com os resultados do presente estudo, a pasta endodôntica Feapex parece ser a melhor opção para utilização entre as pastas analisadas, pois apresentou menor citotoxicidade que as pastas Calen PMCC e CTZ

Objective: The aim of the present study was to evaluate the cytotoxic potential of three different endodontic filling materials on human osteoblast cell cultures. Material and Methods: The endodontic pastes Calen PMCC (SSWhite Dental Articles LTDA, Rio de Janeiro, Brazil), Feapex (Formula and Action, São Paulo, Brazil) and CTZ (Lenzafarm, Belo Horizonte, Brazil) were eluted in cell culture medium during 24 hours in an oven at 37°C and 5% CO2. Four distinct dilutions of these media were performed at the concentrations 1:1, 1:2, 1:4 and 1:8. Cell cultures of Saos-2 Human Osteoblast-like were exposed to these dilutions for 24 hours. The negative control group was performed by exposing the cells to culture medium without contact with any endodontic paste. The cytotoxic potential of these media was evaluated using the MTT assay and the results were transformed into viable cell percentages in relation to the negative control group. Statistical analysis was submitted with a significance level of 5%, using univariate Analysis of Variance (ANOVA) followed by Tukey's test. Results: Cell viability was significantly altered according to the material tested (p<0.05) and its concentration (p<0.05). Feapex samples presented higher cell viability than the other materials in all concentrations tested (p<0.05). Although no statistically significant difference was observed between Calen PMCC paste and CTZ paste at concentrations of 1: 1 and 1: 2 (p>0.05), CTZ paste showed a higher cytotoxicity at concentrations of 1: 4 and 1: 8 (p<0.05). In general, cytotoxicity decreases with increasing material dilution. Conclusion: According to the results of the present study, Feapex endodontic paste seems to be the better option for use among the analyzed pastes, since it presented lower cytotoxicity than Calen PMCC and CTZ pastes

Resistência de união à dentina de um material fotopolimerizável à base de silicato de cálcio e modificado por resina / Dentin bond strength of resin-modified light-curable calcium-silicate-based material

Objetivo: este estudo teve como objetivo comparar a resistência de união à dentina de um material à base de silicato de cálcio fotopolimerizável modificado por resina (TheraCal LC®; Bisco, Schaumburg, IL, EUA) com MTA branco (WMTA®; Angelus, Londrina, PR, Brasil). Materiais e Métodos: dezesseis incisivos superiores e caninos humanos foram selecionados e três discos de 1 mm foram obtidos a partir do terço médio de cada raiz. Na superfície coronal de cada disco, dois furos de 1,2 mm de largura foram perfurados na dentina. Em seguida, os buracos artificiais foram preenchidos com um dos materiais testados: WMTA® e TheraCal LC®. As fatias dentárias preenchidas foram armazenadas em uma solução salina tamponada com fosfato (PBS) (pH 7,2) por 7 dias a 37°C. Depois disso, a avaliação do push-out foi realizada com uma ponta do êmbolo de 1,0 mm. A carga foi aplicada a uma velocidade de 0,5 mm / min até o deslocamento do selador. Os resultados foram expressos em MPa. O teste U de Mann-Whitney foi aplicado para classificar os materiais quanto à resistência adesiva à dentina. O nível de significância foi estabelecido em = 5%. Resultados: todas as amostras apresentaram resultados de resistência de união à dentina mensuráveis e não ocorreram falhas prematuras. O TheraCal LC® demonstrou valores superiores de resistência de união à dentina quando comparado ao WMTA® (P<0,0001). Conclusões: existe uma vantagem do TheraCal LC® sobre o WMTA® no que diz respeito à resistência da união ao empurrar e, portanto, pode ser considerado um material reparador promissor e inovador

Objective: this study aimed to compare the dentin bond strength of a resin-modified light-curable calcium-silicate-based material (TheraCal LC®; Bisco, Schaumburg, IL, USA) with White MTA (WMTA®; Angelus, Londrina, PR, Brazil). Materials and Methods: sixteen human maxillary incisors and canines were selected and three 1-mm-discs were obtained from the middle third of each root. On the coronal surface of each disc, two 1.2-mm-wide-holes were drilled through the dentin. Then, artificial holes were filled with one of the tested materials: WMTA® and TheraCal LC®. The filled dental slices were stored in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days at 37°C. After that, push-out assessment was performed with a 1.0-mm-plunger-tip. Load was applied at a crosshead speed of 0.5 mm/min until sealer displacement. The results were expressed in MPa. Mann-Whitney U test was applied to rank materials regarding dentin push-out bond strength. Significance level was set at a = 5%. Results: All specimens showed measurable results and no premature failure occurred. TheraCal LC® demonstrated superior push-out bond strength values to dentin when compared to WMTA® (P<0.0001). Conclusions: there is advantage of TheraCal LC® over WMTA® as regards to the push-out bond strength and, therefore it may be taken as a promising and innovative reparative material

Postoperative pain after root canal filling with different endodontic sealers: a randomized clinical trial

Abstract The aim of this randomized clinical trial was to compare the occurrence and intensity of postoperative pain and analgesic intake after root canal treatment, using different root canal sealers. Sixty single-rooted teeth diagnosed with asymptomatic necrosis and apical periodontitis were randomly assigned to 3 experimental groups (n=20), according to the root canal sealer: AH Plus, Endofill or MTA Fillapex. Endodontic treatment was performed in two sessions, and calcium hydroxide was used as the intracanal dressing. Patients were instructed to record pain intensity as none, slight, moderate and severe. Scores from 1 to 4 were attributed to each level of pain after 24 h, 48 h and 7 days. The need for analgesic intake was also recorded. Differences in the incidence of postoperative pain and the need for an analgesic were analyzed using the chi-square test. Differences in pain intensity after treatment were analyzed using the ordinal (linear) chi-square test. No significant differences were detected among the groups in terms of either incidence or intensity of postoperative pain, or need for analgesic intake, at any timepoint (p>0.05). No pain was reported after 7 days. AH Plus, Endofill and MTA Fillapex used for filling root canals resulted in the same rate of postoperative pain and need for analgesic medication.

Correlação dos diâmetros e conicidades de instrumentos reciprocantes com cones de guta-percha para obturação com cone único / Correlation of the diameters and tapers of reciprocating instruments with gutta-percha points for single-cone root canal filling

Objetivo: o presente estudo teve como objetivo caracterizar as dimensões dos instrumentos Reciproc R25 e X1 Blue File, e dos cones de guta-percha da Mk Life R25, Reciproc R25 e DiaDent R25, para verificar qual cone de guta-percha se adapta melhor no preparo dos instrumentos. Métodos: dez instrumentos Reciproc R25 25/0,08v e X1Blue File 25/0,06; e dez cones de guta-percha Dia- Dent R25, Mk Life R25 e Reciproc R25 foram utilizados. As imagens foram obtidas através de uma lupa estereoscópica com uma câmera digital acoplada. As medidas foram obtidas através do programa TS View. Os diâmetros dos instrumentos e dos cones de guta-percha foram determinados em D0 até D9, com intervalos de medidas de 1,0 mm; e a conicidade foi calculada adotando-se os diâmetros D8 e D1. Os resultados obtidos foram submetidos à análise estatística utilizando o programa Primer of biostatistics versão 6.0. Resultados: apesar da maior conicidade dos instrumentos X1Blue file (0,07mm/mm), não houve diferença estatisticamente significativa entre os instrumentos nos três primeiros milímetros (p > 0,05), o mesmo ocorreu para a conicidade dos cones (p > 0,05). Os cones de guta-percha apresentaram diferença estatisticamente significativa em todos os diâmetros aferidos (p < 0,05). Conclusão: os instrumentos e os cones de guta-percha atenderam à recomendação das respectivas normas ANSI/ADA. O cone de guta-percha que apresentou maior compatibilidade dimensional com os diâmetros dos instrumentos foi o MK life, e VDW foi o que apresentou maior desajuste (AU).

Objective: The aim of this study was to characterize the dimensions of the Reciproc R25 and X1 Blue File instruments and the gutta-percha points of Mk Life R25, Reciproc R25 and DiaDent R25 to verify which gutta-percha point better fits to the instruments preparation. Material and methods: Ten Reciproc R25 25/0.08v and X1Blue File 25/0.06 instruments; and ten DiaDent R25, Mk Life R25 and Reciproc R25 gutta-percha points were used. The images were obtained through a stereomicroscopic with a digital camera coupled. The measurements were obtained through the TS View program. The diameters of instruments and gutta-percha points were determined in D0 through D9 at 1.0 mm intervals, and the taper was calculated by adopting diameters D8 and D1. The results were submitted to statistical analysis using the program Primer of biostatistics version 6.0. Results: Despite the greater taper of the X1Blue file instruments (0.07mm /mm), there was no statistically significant difference between the instruments in the first 3 millimeters (p> 0.05), the same was observed for the tapers of the guta-percha points (p> 0.05). The gutta-percha points presented a statistically significant difference in all measured diameters (p <0.05). Conclusion: Gutta-percha points and instruments have met the recommendations of their respective ANSI/ADA standards. The gutta-percha point that presented greater dimensional compatibility with the diameters of the instruments was the MK life, and VDW presented the greatest mismatch (AU).

Fadiga cíclica e resistência torcional de instrumentos reciprocantes tratados termicamente tipo Gold / Cyclic fatigue and torsional resistance of Gold-type thermally treated reciprocating instruments

Objetivo: o objetivo do presente estudo foi avaliar a fadiga cíclica e torcional dos instrumentos WA1 e WaveOne Gold. Métodos: vinte instrumentos do sistema WA1 (25/0,07v) e vinte instrumentos do sistema WaveOne Gold (25/0,07v) foram utilizados. A resistência à fadiga cíclica foi testada, medindo o tempo até a fratura em um canal artificial curvo de aço inoxidável com ângulo de 80° e raio de curvatura de 3 mm (n = 10). O torque máximo e ângulo de rotação no momento da falha dos instrumentos (n = 10) foram medidos de acordo com a norma ISO 3630-1. A superfície de fratura de todos os fragmentos foi examinada com um microscópio eletrônico de varredura. Os resultados foram analisados estatisticamente usando o teste t de Student com um nível de significância de 5%. Resultados: não foram observadas diferenças na vida em fadiga cíclica dos instrumentos testados (p > 0,05). A força máxima de torção dos instrumentos WA1 foi menor do que os instrumentos WaveOne Gold (p < 0,05); entretanto, não foram observadas diferenças no ângulo máximo de rotação de ambos os sistemas (p > 0,05). A fotomicrografia eletrônica de varredura da superfície da fratura revelou características similares e típicas de fadiga cíclica e de falha por torção para os dois tipos de instrumentos. Conclusão: dentro dos resultados do presente estudo, pode-se concluir que os instrumentos WaveOne Gold e WA1 tiveram comportamento similar com relação à fadiga cíclica. No entanto, o instrumento WaveOne Gold apresentou maior deflexão angular à fratura por torção, em comparação aos instrumentos WA1 (AU).

Introduction: The aim of the present study was to evaluate the cyclic and torsional fatigue resistance of WA1 and WaveOne Gold instruments. Methods: Twenty instruments of the WA1 system (25/0.07v) and twenty instruments of the WaveOne Gold system (25/0.07v) were used. The cyclic fatigue resistance was tested by measuring the time to fracture in a stainless steel curved artificial canal with an angle of 80° and a radius of curvature of 3 mm (n = 10). The maximum torque and rotation angle at instrument failure (n = 10) were measured according to ISO 3630-1. The fracture surface of all the fragments was examined with a scanning electron microscope. The results were statistically analyzed using the student t-test with a significance level of 5%. Results: There were no differences in cyclic fatigue life of the tested instruments (P> 0.05). The maximum torsional force of the WA1 instruments was lower than the WaveOne Gold instruments (P <0.05); however, no differences were observed in the maximum rotation angle of both systems (P> 0.05). The scanning electron photomicrographs of the fracture surface revealed similar and typical characteristics of cyclic fatigue and torsional failure for the 2 types of instruments. Conclusion: Within the results of the present study, it can be concluded that WaveOne Gold and WA1 instruments had similar behavior regarding cyclic fatigue. However, WaveOne Gold instruments presented greater angular deflection to torsional fracture than WA1 instruments.

Autotransplantation of teeth with complete rhizogenesis: a literature review

Objective: The objective of the present literature review tis o verify the success rates, as well as the predisposing factors, associated to success rates of dental autotransplant treatments in teeth with complete rhizogenesis. Methods: An electronic search was performed on PubMed database using MeSH terms and free terms. Initially, a total of 115 titles and abstracts. An additional study was identified as relevant after a search of reference lists. After eligibility criteria appliance, only 8 articles were selected. Results: In general, the included studies show high success rates, based on established parameters such as periodontal ligament maintenance, periapical healing and periodontal health. In addition, the selected studies pointed out that factors such as extraction and reimplantation protocols, the time of follow-up used in the study and the time in which the endodontic treatment of the transplanted element was performed, can affect the success rate of dental transplant therapy. Conclusion: According to the present literature review, it can be concluded that although there are still few studies of autotransplantation performed in patients with complete rhizogenesis, the technique has proven itself as a viable option with moderate success rate for replacement of lost dental elements.

Objetivo: O objetivo da presente revisão da literatura foi verificar as taxas de sucesso, assim como seus fatores predisponentes, do autotransplante dentário em dentes com rizogênese completa. Métodos: Uma busca eletrônica foi executada no PubMed usando MeSH terms e termos livres específicos. Inicialmente, um total de 115 títulos e resumos foram identificados. Um estudo adicional foi identificado como relevante após uma busca das listas de referência. Após a aplicação dos critérios de elegibilidade, apenas 8 artigos foram selecionados. Resultados: De forma geral, os estudos incluídos demonstram elevadas taxas de sucesso, baseado nos parâmetros estabelecidos, como manutenção do ligamento periodontal, cicatrização periapical e saúde periodontal. Além disso, os estudos selecionados na presente revisão apontaram que fatores como os protocolos de extração e reimplante, o tempo de proservação utilizado no estudo e o tempo no qual foi realizado o tratamento endodôntico do elemento transplantado, podem afetar a taxa de sucesso do autotransplante dentário. Conclusão: De acordo com a presente revisão de literatura pode-se concluir que embora ainda existam poucos estudos de autotransplante realizados em pacientes com rizogênese completa, a técnica tem se mostrado uma opção viável e com moderada taxa de sucesso para a substituição de elementos dentários perdidos.

Influence of chlorhexidine and zinc oxide in calcium hydroxide pastes on pH changes in external root surface

Abstract The objective of this study was to assess the influence of chlorhexidine (liquid and gel) and zinc oxide in calcium hydroxide (CH) pastes on root pH in simulated external resorption. One hundred human anterior teeth with a single root canal were selected. After decoronation and root canal instrumentation, the specimens were divided into 4 experimental groups and 1 control group (without intracanal paste): CH + saline (CH+S), CH + 2% chlorhexidine liquid (CH+ CHX), CH + 2% chlorhexidine gel (CH+ CHXg), and CH + 2% chlorhexidine gel + zinc oxide (CH+ CHXg+ZnO). pH was measured using a microelectrode at 3 and 24 h, and 1, 2, 3, and 4 weeks after inserting intracanal pastes. Data were analyzed statistically using an ANOVA and Tukey's test (p < 0.05). The CH+CHXg+ZnO group had the highest pH values throughout (p<0.05). The CH+S and CH+ CHX groups had the highest pH values after 1 week and the CH+ CHXg group after 2 weeks. CH+ CHXg maintained the highest pH until the fourth week compared with CH+ CHX (p < 0.05). The control group remained at a neutral pH at all evaluated times. It can be concluded that chlorhexidine solution or gel maintained the alkaline pH of CH, and chlorhexidine gel allowed a slower decrease in pH over time. CH+ CHXg+ZnO showed the highest pH values and was an effective intracanal medication for maintaining alkaline root pH in the area of resorption.

Bond strength of experimental root canal sealers based on mta and butyl ethylene glycol disalicylate

Abstract This study investigated the bond strength of two experimental root canal sealers based on MTA and butyl ethylene glycol disalicylate: MTAe and MTAe-HA. The reference materials used for comparison were AH Plus and MTA Fillapex. Twenty human upper incisors were selected and one 1 mm slice was obtained from the cervical third of each root. On the coronal surface of each slice, four 0.9 mm wide holes were drilled through the dentine. Standardized irrigation was performed and holes were filled with one of the four tested sealers: AH Plus, MTA Fillapex, MTAe, and MTAe-HA. The filled slices were stored in a PBS solution (pH 7.2) for 7 days at 37 °C. A push-out assessment was performed with a 0.7 mm plunger tip. Load was applied at a crosshead speed of 0.5 mm/min until sealer displacement. The results were expressed in MPa. The Kruskal-Wallis test was applied to assess the effect of each sealer on the push-out bond strength. Mann-Whitney with Bonferroni correction was used to isolate the differences. The alpha-type error was set at 0.05. Significant differences among medians values obtained by materials were observed (p<0.001). AH Plus displayed the highest value of bond strength (p<0.001). In contrast, MTA Fillapex presented the lowest bond strength among all tested sealers (p<0.001). Experimental sealers showed intermediary bond strength values, with no statistical differences between them (p>0.05). In conclusion, experimental root canal sealers presented suitable bond strength outcomes when compared to MTA Fillapex.

Resumo Esse estudo investigou a resistência de união de dois cimentos endodônticos experimentais à base de MTA e butiletilenoglicol dissalicilato: MTAe e MTAe. Os materiais de referência utilizados para comparação foram os cimentos endodônticos MTA Fillapex e AH Plus. Vinte incisivos superiores humanos foram selecionados e um slice dentinário de 1 mm de espessura foi obtido do terço cervical de cada raiz. Na superfície coronária de cada slice, quatro orifícios com 0,9 mm de diâmetro foram confeccionados através da dentina. Uma irrigação padronizada foi realizada e os orifícios foram preenchidos com um dos quatro cimentos endodônticos avaliados: AH Plus, MTA Fillapex, MTAe, e MTAe-HA. Os slices preenchidos foram armazenados em solução PBS (pH 7,2) durante 7 dias a 37°C. O ensaio de push-out foi realizado por meio de um dispositivo com 0,7 mm de diâmetro. A carga foi aplicada com a velocidade de 0,5 mm/min até a obtenção de deslocamento do material obturador. Os resultados foram expressos em MPa. O teste de Kruskal-Wallis foi aplicado para avaliar o efeito da resistência de união de cada cimento endodôntico. O teste de Mann-Whitney com correção de Bonferroni foi utilizado para isolamento das diferenças. O erro do tipo-alfa foi fixado em 0,05. Diferenças significantes entre os valores de medianas obtidos pelos materiais foram observados (p<0,001). O AH Plus demonstrou os maiores valores de resistência de união (p<0,001). Em contraste, o MTA Fillapex apresentou a menor resistência de união entre todos os cimentos testados (p<0,001). Os cimentos experimentais demonstraram valores intermediários, com ausência de diferenças estatísticas entre si (p>0,05). Em conclusão, os cimentos endodônticos experimentais à base de MTA e butiletilenoglicol dissalicilato apresentaram resultados adequados de resistência de união quando comparados ao MTA Fillapex.

Improved sealing ability promoted by calcium silicate-based root canal sealers

Aim: This study investigated the sealing ability produced by AH Plus (Dentsply DeTrey, Konstaz, Germany), EndoSequence BC sealer (Brasseler USA, Savannah, GA, USA), GuttaFlow (Coltène/Whaledent, Altstätten, France) and MTA Fillapex (Angelus, Londrina, Brazil). Methdos: A total of forty-six single-root human canines were prepared and randomly divided into four experimental groups (n=10): MTA Fillapex, EndoSequence BC Sealer, AH Plus or GuttaFlow. Teeth with intact crowns served as negative controls (n=3) and teeth filled with only gutta-percha served as positive controls (n=3). Teeth were mounted in a two-chamber apparatus and exposed to Enterococcus faecalis. The number of days over a 60-days period was recorded for the appearance of turbidity in the lower chamber. Kaplan-Meier method was used to estimate the survival curves. The nonparametric log-rank test was used to compare the survival curves using a significance level of 0.05. Results: The results at the end of the observation time were further analyzed by chi-square testing. All positive controls leaked within 24 h, whereas none of the negative controls leaked after 60 days. EndoSequence BC Sealer and MTA Fillapex had significant less bacterial leakage (P<0.05) than the other tested sealers. No significant difference between AH Plus and GuttaFlow was observed (P>0.05). Conclusion: In conclusion, calcium-silicate based root canal sealers promoted improved sealing ability when compared to other endodontic sealers

Evaluation of the efficacy of filling material removal and re-filling after different retreatment procedures

Abstract This study analyzed the influence of different retreatment protocols on amount of remaining filling material and amount of new sealer after endodontic retreatment. Forty mandibular molars with curved mesial roots were prepared with ProTaper Universal system, and filled with AH Plus sealer mixed with 0.1% rhodamine B and gutta-percha. After 7 days, the specimens were randomized according to the retreatment protocol (n = 10): ProTaper Retreatment System (PTR); PTR+Orange Oil (PTR+OO); PTR+Passive Ultrasonic Irrigation (PTR+PUI). No retreatment was performed in the control group (CG). After retreatment, the root canals were filled with AH Plus mixed with 0.1% fluorescein and gutta-percha. Samples were evaluated under confocal laser scanning microscopy and analyzed using Image J software. Data were analyzed using Kruskal-Wallis and Dunn tests (p < 0.05). Regarding presence of residual filling, the Kruskal-Wallis test indicated no differences among the different retreatment techniques in the perimeter and the isthmus analyses (p > 0.05); however, PTR+PUI was associated with a lesser amount of residual filling material in the canal area analysis (p < 0.05). In evaluating the new filling, the perimeter analysis showed a lesser amount of new endodontic sealer in the PTR group (p < 0.05). Moreover, the PTR+PUI group presented a significantly greater amount of new endodontic sealer in the canal area analysis (p < 0.05). There was no difference among groups in the isthmus analysis (p > 0.05). It can be concluded that PTR associated to PUI yielded better results in removing root canal filling material from the canal area. However, none of the protocols resulted in root walls completely free of remnants.