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.

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

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.

Does sodium thiosulphate avoid the formation of the brown-coloured precipitate as an intermediate irrigant between NaOCl and chlorhexidine?

This study evaluated the efficacy of sodium thiosulphate (ST) as an intermediate irrigant between sodium hypochlorite (NaOCl) and chlorhexidine (CHX) to avoid the formation of the brown-coloured precipitate. The in vitro experiment used microtubes to test the mixture of 2.5% NaOCl, 2% CHX and 5% ST solutions, varying their order and time of addition. In the ex vivo experiment, 10 bovine teeth were divided into two groups according to the intermediate irrigant used: distilled water (control) and 5% ST (experimental). Colour change occurred in all microtubes after interaction between solutions. While the precipitate was not observed in the experimental group, it was seen in all specimens of the control group. The 5% ST was able to prevent the formation of the brown-coloured precipitate in the ex vivo experiment, whereas it only prevented its in vitro formation when the waiting time for adding CHX was 10, 15 and 20 min.

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

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.

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).

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

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.

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.

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

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.

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).

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.

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.

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.

Longevity of defective direct restorations treated by minimally invasive techniques or complete replacement in permanent teeth: A systematic review.

OBJECTIVES: This systematic review aimed to verify if there is difference in the longevity of minimally invasive techniques compared to the complete replacement for the treatment of defective direct restorations in permanent teeth. DATA: The data included randomized controlled clinical trials comparing the clinical performance of defective dental restorations treated by a complete replacement technique or minimally invasive techniques on permanent teeth. Evaluation of the risk of bias was performed using the Cochrane Collaboration common scheme for bias and the evidence was qualified using the GRADE tool. SOURCE: A comprehensive search was performed in the electronic databases: PubMed, Scopus, ISI Web of Science, The Cochrane Library, LILACS, BBO, SIGLE, followed by manual search in the reference lists of the included studies, without any restrictions. STUDY SELECTION: From 5554 retrieved studies, 10 met the eligibility criteria and were submitted to data extraction and quality assessment. The repair technique presented similar results to replacement and superior results when compared to sealing. In addition, refurbishment demonstrated to be a useful treatment for localized anatomical form defects. All the studies presented low risk of bias and high quality evidence for repair and refurbishment and moderate for the sealing technique. CONCLUSIONS: The direct restorations treated by the repair, seal and refurbishment techniques did not present a significant difference in clinical longevity in comparison to the replacement technique in permanent teeth with overall moderate quality of evidence. CLINICAL SIGNIFICANCE: The present findings demonstrated that the best treatment for defective restorations is conservative management. The evidence demonstrated here helps and encourages clinicians during the decision-making process. Moreover, it suggests not replacing imperfect restorations, but to managing them in a minimally invasive way, allowing the structure to be preserved.

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

Effect of Intermediate Flush Using Different Devices to Prevent Chemical Smear Layer Formation.

This study compared the effect of intermediate flush with distilled water delivered by conventional irrigation, EndoVac microcannula or Self-Adjusting File (SAF) system in the prevention of chemical smear layer (CSL) formation. Thirty human premolars were used. Canals were prepared with Reciproc system and 5.25% NaOCl. After chemomechanical preparation, samples were divided in 3 groups (n=10) according to the intermediate irrigation protocol with distilled water using: conventional irrigation, EndoVac microcannula or SAF. A final flush with 2% chlorhexidine solution was used and scanning electron microscopy was performed to assess protocol effectiveness. Two calibrated evaluators attributed scores according the presence or absence of CSL on the surface of the root canal walls at the coronal, middle and apical thirds, as follows: (1) no CSL; (2) small amounts of CSL; (3) moderate CSL; and (4) heavy CSL. Differences between protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. SAF resulted in less formation of CSL when compared with the conventional irrigation and EndoVac microcannula (p<0.05). When root canal thirds were analyzed, conventional irrigation and EndoVac groups showed less CSL formation at coronal and middle thirds in comparison to the apical third (p<0.05). In SAF group, there was no difference among the thirds (p>0.05). It may be concluded that an intermediate flush of distilled water, delivered by the SAF system resulted in a better reduction of CSL formation during chemomechanical preparation.