Abstract The present study aimed to evaluate bacterial viability after the use of different disinfection protocols in root canals infected with a multispecies biofilm (MB) formed in situ. Palatal roots with a single canal were obtained from extracted maxillary molars and sterilized before being inserted into the mouth. The roots were contaminated with a MB in an intraoral appliance worn by ten volunteers. All volunteers wore six roots simultaneously in two intraoral devices for 21 days. One root from each volunteer was assigned to each group (n=10): PUI - passive ultrasonic irrigation; EC - Easy Clean; XPF - XP-endo Finisher; aPDT - antimicrobial photodynamic therapy; CI - conventional irrigation; and NC - negative control. The samples were evaluated under confocal laser scanning microscopy. The percentage of viable cells (VC) was calculated over the total percentage of MB biovolume. Data were statistically analyzed (α=5%). The cell viability in the entire root canal or for each third was compared between groups (Kruskal-Wallis test, Dunn post-hoc test) and for the same group (Friedman test, Dunn post-hoc test). Disinfection protocols were not significantly different from each other (P>.05). Samples in EC, PUI, and aPDT had lower cell viability than in NC (P<.05). In the coronal third of samples in the EC, XPF, PUI and aPDT, the percentage of VC biovolume was lower than in the NC (P<.05). The percentage of VC in EC samples was lower in the coronal and middle thirds than in the apical third (P<.05). EC, PUI and aPDT had significant effects on cell viability in intraradicular multispecies biofilm formed in situ when compared with untreated samples.

Resumo O presente estudo teve como objetivo avaliar a viabilidade bacteriana após o uso de diferentes protocolos de desinfecção em canais radiculares infectados com um biofilme multiespécies (MB) formado in situ. Raízes palatinas com canal único foram obtidas de molares superiores extraídos e esterilizadas antes de serem inseridas na boca. As raízes foram contaminadas com MB em um aparelho intraoral usado por dez voluntários. Todos os voluntários usaram seis raízes simultaneamente em dois dispositivos intrabucais por 21 dias. Uma raiz de cada voluntário foi atribuída a cada grupo (n=10): PUI - irrigação ultrassônica passiva; EC - Easy clean; XPF - XP-endo Finisher; aPDT - terapia fotodinâmica antimicrobiana; IC - irrigação convencional; e, NC - controle negativo. As amostras foram avaliadas em microscopia confocal de varredura a laser. A porcentagem de células viáveis (VC) foi calculada sobre a porcentagem total do biovolume de MB. Os dados foram analisados estatisticamente (α=5%). A viabilidade celular em todo o canal radicular ou em cada terço foi comparada entre os grupos (teste de Kruskal-Wallis, teste post-hoc de Dunn) e no mesmo grupo (teste de Friedman, teste post-hoc de Dunn). Os protocolos de desinfecção não foram significativamente diferentes entre si (P>0,05). Amostras dos grupos EC, PUI e aPDT apresentaram menor viabilidade celular do as do NC (P<0,05). No terço cervical das amostras do EC, XPF, PUI e aPDT, a porcentagem de biovolume de VC foi menor do que no NC (P<0,05). A porcentagem de VC nas amostras do EC foi menor nos terços cervical e médio do que no terço apical (P<0,05). EC, PUI e aPDT tiveram efeitos significativos na viabilidade celular do biofilme multiespécies intrarradicular formado in situ quando comparado com amostras não tratadas. Estudos clínicos devem investigar o papel da redução de cargas bacterianas viáveis no sistema de canais radiculares para o sucesso do tratamento endodôntico.

Abstract This ecological study assessed the impact of the COVID-19 pandemic on completed treatments (CTs) and referrals during urgent dental visits to primary health care units in Brazil, and their associations with socioeconomic, geodemographic, and pandemic index factors in Brazilian municipalities. The difference in rates of procedures 12 months before and during the pandemic was calculated. Data were extracted at baseline from health information systems of all municipalities that provided urgent dental care (n = 5,229 out of 5,570). Multiple logistic regression predicted the factors associated with referrals and CTs. The number of dental urgencies increased from 3,987.9 to 4,272.4 per 100,000 inhabitants. The rates of referrals decreased in 44.1% of the municipalities, while 53.9% had lower rates of CTs. Municipalities with a greater number of oral health teams in the primary health care system (OR = 1.52, 95%CI:1.21–1.91) and with specialized services (OR = 1.80, 95%CI:1.50–2.16) were more likely to decrease referrals during the pandemic. Higher HDI and GDP per capita were associated with a larger decrease in referrals and smaller decrease in CTs. The calamity generated by the long pandemic period resulted in a greater demand for urgent visits. Less developed and larger cities seem to have been more likely to not complete treatments during urgent visits in primary dental care units in times of calamity. Primary dental care offices in smaller and less developed municipalities should be better equipped to provide appropriate assistance and to improve the problem-solving capacity of dental services during emergencies.

Abstract: This study assessed the ability of XP-endo Finisher R (FKG, La Chaux-de-Fonds, Switzerland) to remove filling remnants from curved mesiobuccal canals of maxillary molars, using the passive ultrasonic irrigation (PUI) technique as a comparison. Twenty-four curved main mesiobuccal canals (MB1) of maxillary molars were instrumented with Wave One (#25/07) and filled with gutta-percha points and AH Plus Sealer. Samples were then re-treated with a standardized protocol with Wave One (#35/06) as the master apical file. Micro-CT scans measured baseline volume of remaining filling material (in mm3). Samples were divided into two groups (n = 12) according to the supplementary cleaning approach: (PUI) or XP-endo Finisher R. Statistics compared baseline and final volume of filling material (within-group); and the percentage of filling material reduction (between-group). Mean baseline volumes, final volumes, and percentages of reduction (%) of filling material for XP-endo Finisher R and PUI were respectively: 0.060 mm3, 0.042 mm3, and 31.28%; and 0.064 mm3, 0.054 mm3, and 16.57%. Both tested protocols reduced the amount of filling material (p < 0.05). XP-endo Finisher R had higher percentage of reduction as compared to PUI (p < 0.05). XP-endo Finisher R and PUI used as supplementary cleaning protocols during re-treatment improved the removal of root filling material in curved canals; but XP-endo Finisher R was approximately twice more efficient. The complete filling material removal during re-treatment procedures is still a challenge. Supplementary cleaning protocols may help to remove the remaining material after the complete mechanical preparation of curved canals. XP-endo Finisher R was approximately twice more efficient than PUI.

Abstract: This study aimed to compare the physicochemical properties of MTA Angelus (MTA-A), MTA Repair HP (MTA-HP), and Biodentine (BD). Setting times (n = 7) were determined in accordance with ASTM C266–15. Solubility (n = 11), pH (n = 10), and calcium ion release (n = 10) were evaluated up to 28 days in accordance with ANSI/ADA specification no. 57. Radiopacity was assessed by ANSI/ADA (n = 10) and the tissue simulator method (n = 10). In both methods, the specimens were radiographed using an aluminum stepwedge and the digital radiographs were analyzed in Adobe Photoshop, determining the mean grayscale pixel values of the materials, of the 3-mm aluminum stepwedge, and of the dentin, the latter of which was analyzed on the tissue simulator. The data obtained from each test were statistically analyzed and compared (p < 0.05). MTA-A presented longer final setting time compared with the other materials. There were no significant differences in the mass values of materials during the experiment. All materials presented an alkaline pH. BD promoted greater calcium ion release in most of the experimental periods. All materials presented appropriate radiopacity. BD showed lower radiopacity than MTA-A in the tissue simulator method. All groups presented higher radiopacity in the tissue simulator when compared with the ANSI/ADA method. MTA-A, MTA-HP, and BD showed appropriate physicochemical properties and radiopacity, and were considered suitable to be used in clinical practice.

Este estudo ecológico descreveu como a pandemia da COVID-19 e o desenvolvimento socioeconômico afetaram o uso da assistência odontológica de urgência (AOU) e seu perfil. Comparamos taxas de AOU para cada 100 mil habitantes antes (de março a junho de 2019) e durante (de março a junho de 2020) a pandemia da COVID-19 em 4.062 municípios brasileiros. Os dados foram coletados de fontes oficiais. As taxas de mortalidade e internação pela COVID-19 indicaram níveis restritivos de lockdown e Índices de Desenvolvimento Humano (IDH) indicou o nível de desenvolvimento socioeconômico. Foram utilizadas regressões logísticas múltiplas e risco relativo de excesso devido à interação (RERI) para análises estatísticas. O teste t de Student foi usado para comparar alterações no perfil das causas e procedimentos da AOU nos dois períodos. As taxas de AOU foram menores em 69,1% dos municípios e associadas a IDH maior (OR = 1,20; IC95%: 1,01; 1,42). A mortalidade apresentou uma razão de chances de 0,88 (IC95%: 0,73; 1,06) para municípios com IDH < 0,70 e de 1,45 (IC95%: 1,07; 1,97) para municípios com IDH > 0,70. O RERI entre IDH e COVID-19 foi de 0,13 (p < 0,05). Os municípios com maior cobertura de atenção primária à saúde apresentaram menor redução nas suas taxas de emergência. Procedimentos endodônticos e dor dentária foram os fatores mais frequentes antes e durante a pandemia. O percentual de AOUs aumentou devido à dor, danos nos tecidos moles, vedação temporária e procedimentos cirúrgicos. Variáveis socioeconômicas afetaram as taxas de AOU durante o período mais restritivo da pandemia da COVID-19 e devem ser incluídas no planejamento de ações de saúde em emergências futuras.

This ecological study described the effect of the COVID-19 pandemic and socioeconomic development on the use and profile of urgent dental care (UDC). UDC rates per 100,000 inhabitants before (from March to June 2019) and during (from March to June 2020) the COVID-19 pandemic in 4,062 Brazilian municipalities were compared. Data were collected from official sources. COVID-19 mortality and hospitalization rates were indicative of levels of lockdown and Human Development Index (HDI) indicated socioeconomic development. Multiple logistic regression and relative excess risk due to interaction (RERI) were used for statistical analyses. The Student t-test was used to compare changes in the profile of UDC causes and procedures in the two periods. Lower UDC rates were found in 69.1% of municipalities and were associated with higher HDI (OR = 1.20; 95%CI: 1.01; 1.42). Mortality had OR = 0.88 (95%CI: 0.73; 1.06) for municipalities with HDI < 0.70 and OR = 1.45 (95%CI: 1.07; 1.97) for municipalities with HDI > 0.70. RERI between HDI and COVID-19 was 0.13 (p < 0.05). Municipalities with greater primary health care coverage had a smaller reduction in emergency rates. Endodontic treatment and dental pain were the most frequent factors both before and during the pandemic. The percentage of UDCs due to pain and soft tissue damage, as well as temporary sealing and surgical procedures, increased. Socioeconomic variables affected UDC rates during the most restrictive period of the COVID-19 pandemic and should be considered in the planning of health actions in future emergencies.

Este estudio ecológico describió el efecto de la pandemia de COVID-19 y el desarrollo socioeconómico en el uso y el perfil de la atención odontológica de urgencia (AOU). Se compararon las tasas de AOU por cada 100.000 habitantes antes de la pandemia de COVID-19 (de marzo a junio de 2019) y durante la pandemia de COVID-19 (de marzo a junio de 2020) en 4.062 municipios brasileños. Los datos se recogieron de fuentes oficiales. Las tasas de mortalidad y hospitalización de COVID-19 fueron indicativas de niveles restrictivos de desarrollo socioeconómico e Índice de Desarrollo Humano (IDH). Para los análisis estadísticos se utilizó la regresión logística múltiple y el exceso de riesgo relativo (ERR) debido a la interacción. Se utilizó la prueba t de Student para comparar los cambios en el perfil de las causas y los procedimientos de AOU en los dos períodos. Las tasas de AOU fueron menores en el 69,1% de los municipios y se asociaron con un IDH más alto (OR = 1,20; IC95%: 1,01; 1,42). La mortalidad tuvo una OR de 0,88 (IC95%: 0,73; 1,06) para los municipios con IDH < 0,70 y de 1,45 (IC95%: 1,07; 1,97) para los municipios con IDH > 0,70. El ERR entre el IDH y el COVID-19 fue de 0,13 (p < 0,05). Los municipios con mayor cobertura de atención primaria tuvieron una menor reducción de las tasas de urgencia. Los procedimientos de endodoncia y la causa del dolor dental fueron los factores más frecuentes tanto antes como durante la pandemia. Aumentó el porcentaje de AOU por dolor y daños en los tejidos blandos, así como el sellado temporal y los procedimientos quirúrgicos. Las variables socioeconómicas afectaron a las tasas de AOU durante el periodo más restrictivo de la pandemia de COVID-19 y deberían incluirse en la planificación de las acciones sanitarias en futuras emergencias.

Este estudo ecológico descreveu como a pandemia da COVID-19 e o desenvolvimento socioeconômico afetaram o uso da assistência odontológica de urgência (AOU) e seu perfil. Comparamos taxas de AOU para cada 100 mil habitantes antes (de março a junho de 2019) e durante (de março a junho de 2020) a pandemia da COVID-19 em 4.062 municípios brasileiros. Os dados foram coletados de fontes oficiais. As taxas de mortalidade e internação pela COVID-19 indicaram níveis restritivos de lockdown e Índices de Desenvolvimento Humano (IDH) indicou o nível de desenvolvimento socioeconômico. Foram utilizadas regressões logísticas múltiplas e risco relativo de excesso devido à interação (RERI) para análises estatísticas. O teste t de Student foi usado para comparar alterações no perfil das causas e procedimentos da AOU nos dois períodos. As taxas de AOU foram menores em 69,1% dos municípios e associadas a IDH maior (OR = 1,20; IC95%: 1,01; 1,42). A mortalidade apresentou uma razão de chances de 0,88 (IC95%: 0,73; 1,06) para municípios com IDH < 0,70 e de 1,45 (IC95%: 1,07; 1,97) para municípios com IDH > 0,70. O RERI entre IDH e COVID-19 foi de 0,13 (p < 0,05). Os municípios com maior cobertura de atenção primária à saúde apresentaram menor redução nas suas taxas de emergência. Procedimentos endodônticos e dor dentária foram os fatores mais frequentes antes e durante a pandemia. O percentual de AOUs aumentou devido à dor, danos nos tecidos moles, vedação temporária e procedimentos cirúrgicos. Variáveis socioeconômicas afetaram as taxas de AOU durante o período mais restritivo da pandemia da COVID-19 e devem ser incluídas no planejamento de ações de saúde em emergências futuras.

This ecological study described the effect of the COVID-19 pandemic and socioeconomic development on the use and profile of urgent dental care (UDC). UDC rates per 100,000 inhabitants before (from March to June 2019) and during (from March to June 2020) the COVID-19 pandemic in 4,062 Brazilian municipalities were compared. Data were collected from official sources. COVID-19 mortality and hospitalization rates were indicative of levels of lockdown and Human Development Index (HDI) indicated socioeconomic development. Multiple logistic regression and relative excess risk due to interaction (RERI) were used for statistical analyses. The Student t-test was used to compare changes in the profile of UDC causes and procedures in the two periods. Lower UDC rates were found in 69.1% of municipalities and were associated with higher HDI (OR = 1.20; 95%CI: 1.01; 1.42). Mortality had OR = 0.88 (95%CI: 0.73; 1.06) for municipalities with HDI < 0.70 and OR = 1.45 (95%CI: 1.07; 1.97) for municipalities with HDI > 0.70. RERI between HDI and COVID-19 was 0.13 (p < 0.05). Municipalities with greater primary health care coverage had a smaller reduction in emergency rates. Endodontic treatment and dental pain were the most frequent factors both before and during the pandemic. The percentage of UDCs due to pain and soft tissue damage, as well as temporary sealing and surgical procedures, increased. Socioeconomic variables affected UDC rates during the most restrictive period of the COVID-19 pandemic and should be considered in the planning of health actions in future emergencies.

Este estudio ecológico describió el efecto de la pandemia de COVID-19 y el desarrollo socioeconómico en el uso y el perfil de la atención odontológica de urgencia (AOU). Se compararon las tasas de AOU por cada 100.000 habitantes antes de la pandemia de COVID-19 (de marzo a junio de 2019) y durante la pandemia de COVID-19 (de marzo a junio de 2020) en 4.062 municipios brasileños. Los datos se recogieron de fuentes oficiales. Las tasas de mortalidad y hospitalización de COVID-19 fueron indicativas de niveles restrictivos de desarrollo socioeconómico e Índice de Desarrollo Humano (IDH). Para los análisis estadísticos se utilizó la regresión logística múltiple y el exceso de riesgo relativo (ERR) debido a la interacción. Se utilizó la prueba t de Student para comparar los cambios en el perfil de las causas y los procedimientos de AOU en los dos períodos. Las tasas de AOU fueron menores en el 69,1% de los municipios y se asociaron con un IDH más alto (OR = 1,20; IC95%: 1,01; 1,42). La mortalidad tuvo una OR de 0,88 (IC95%: 0,73; 1,06) para los municipios con IDH < 0,70 y de 1,45 (IC95%: 1,07; 1,97) para los municipios con IDH > 0,70. El ERR entre el IDH y el COVID-19 fue de 0,13 (p < 0,05). Los municipios con mayor cobertura de atención primaria tuvieron una menor reducción de las tasas de urgencia. Los procedimientos de endodoncia y la causa del dolor dental fueron los factores más frecuentes tanto antes como durante la pandemia. Aumentó el porcentaje de AOU por dolor y daños en los tejidos blandos, así como el sellado temporal y los procedimientos quirúrgicos. Las variables socioeconómicas afectaron a las tasas de AOU durante el periodo más restrictivo de la pandemia de COVID-19 y deberían incluirse en la planificación de las acciones sanitarias en futuras emergencias.

Resumo Este estudo avaliou a qualidade 3D de retro-obturações, avaliando a presença (volume e percentagem) de “gaps” marginais e “voids” internos formados a partir da retro-obturação com três materiais à base de silicato de cálcio: MTA Angelus (Angelus Soluções Odontológicas, Londrina, PR, Brasil), Biodentine (Septodont Ltd., Saint Maur-des-Faussés, França) and Neo MTA Plus (Avalon Biomed Inc., Bradenton, Flórida, US). Trinta dentes humanos unirradiculares extraídos foram usados. Após tratamento de canal ortrógrado, resecção radicular (3 mm apicais), o prepare da cavidade retrógrada com pontas ultrassônicas foi realizado. Os dentes foram divididos em três grupos (n= 10 cada) seguindo uma randomização estratificada, de acordo com o volume inicial da cavidade retrógrada. Depois da retro-obturação as amostras foram armazenadas por 7 dias. Duas rodadas de escaneamento de micro-CT foram realizadas: logo após o preparo retrógrado (com a cavidade ainda vazia) e 7 dias após a retro-obturação. O volume de “gaps” marginais e de “voids” internos (mm3 e %), bem como, os defeitos totais (soma de “gaps” e “voids”) foram avaliados. Não houve diferença estatística entre os grupos em relação aos “gaps” marginais (P≥ 0,05), “voids” internos (P≥ 0,05), e aos defeitos totais (P≥ 0,05). A mediana (mm3) e porcentagem dos defeitos totais de aprisionamento de ar foi 0,004mm3 e 1,749% para o MTA Angelus, 0,018mm3 e 6,660% para o Biodentine, e 0,012mm3 e 4,079% para o Neo MTA Plus. Todos os materiais tiveram defeitos (“gaps”e/ou “voids”). Não houve diferença entre MTA Angelus, Biodentine e Neo MTA Plus.

Abstract This study evaluated the 3D quality of root-end filling, assessing the presence (volume and percentage) of marginal gaps and internal voids formed after retro-filling with three calcium silicate-based materials: MTA Angelus (Angelus Soluçoes Odontologicas, Londrina, PR, Brazil), Biodentine (Septodont Ltd., Saint Maur-des-Faussés, France) and Neo MTA Plus (Avalon Biomed Inc., Bradenton, Florida, US). Thirty human, extracted, single rooted teeth were used. Orthograde root canal treatment, root resection (3mm shorter than the apex) and retrograde cavity preparation with ultrasonic tips were performed. Teeth were divided into 3 groups (n =10 each) following a stratified randomization according to the initial volume of the root-end cavity. After retrofilling, samples were stored for 7 days. Then, two rounds of micro-CT scans were performed: soon after root-end preparation (with the cavity still empty) and 7 days after root-end filling. Marginal gaps, internal voids volume (mm3 and %), as well as, the overall defects (sum of gaps and voids) were evaluated. Statistics compared the three groups in relation to those defects. There was not statistical difference between groups regarding the marginal gaps (P≥ 0.05), the internal voids (P≥ 0.05), and the overall defects (P≥ 0.05). Median (mm3) and % of overall air-entrapment defects (gaps and/or voids) was: 0.004mm3 and 1.749% for MTA Angelus, 0.018mm3 and 6.660% for Biodentine, and 0.012mm3 and 4.079% for Neo MTA Plus. All materials had gaps and/or voids. No differences were found between MTA Angelus, Biodentine and Neo MTA Plus.

Abstract Objectives This study aimed to investigate patterns and risk factors related to the feasibility of achieving technical quality and periapical healing in root canal non-surgical retreatment, using regression and data mining methods. Methodology This retrospective observational study included 321 consecutive patients presenting for root canal retreatment. Patients were treated by graduate students, following standard protocols. Data on medical history, diagnosis, treatment, and follow-up visits variables were collected from physical records and periapical radiographs and transferred to an electronic chart database. Basic statistics were tabulated, and univariate and multivariate analytical methods were used to identify risk factors for technical quality and periapical healing. Decision trees were generated to predict technical quality and periapical healing patterns using the J48 algorithm in the Weka software. Results Technical outcome was satisfactory in 65.20%, and we observed periapical healing in 80.50% of the cases. Several factors were related to technical quality, including severity of root curvature and altered root canal morphology (p<0.05). Follow-up periods had a mean of 4.05 years. Periapical lesion area, tooth type, and apical resorption proved to be significantly associated with retreatment failure (p<0.05). Data mining analysis suggested that apical root resorption might prevent satisfactory technical outcomes even in teeth with straight root canals. Also, large periapical lesions and poor root filling quality in primary endodontic treatment might be related to healing failure. Conclusion Frequent patterns and factors affecting technical outcomes of endodontic retreatment included root canal morphological features and its alterations resulting from primary endodontic treatment. Healing outcomes were mainly associated with the extent of apical periodontitis pathological damages in dental and periapical tissues. To determine treatment predictability, we suggest patterns including clinical and radiographic features of apical periodontitis and technical quality of primary endodontic treatment.

Resumo Introdução e objetivo: Ainda são escassos os estudos que avaliam com exatidão o sucesso do tratamento e retratamento endodônticos e quais as falhas que realmente impactam no desfecho dos mesmos. Determinar o índice e os fatores preditivos para o sucesso de tratamentos e retratamentos endodônticos, realizados por alunos de graduação com o mesmo nível de aprendizado. Materiais e métodos: Foram verificados os registros de proservação, com pelo menos 12 meses, dos tratamentos endodônticos realizados na Faculdade de Odontologia de Pelotas, analisando o sucesso ou o fracasso endodôntico, de acordo com critérios clínicos e radiográficos. As variáveis preditivas no resultado do sucesso do tratamento foram: dente, número de canais, coroa dentária, sintomas, diagnóstico da polpa e índice periapical radiográfico. As variáveis relacionadas ao tratamento foram: técnica de instrumentação, número de sessões e limite de instrumentação apical. Resultados: 136 tratamentos endodônticos foram realizados com um acompanhamento de, pelo menos, 12 meses. A avaliação mostrou que o sucesso endodôntico foi influenciado pelo número de sessões (P = 0,015), diagnóstico inicial e grupo dentário (P= 0.014). Também foi possível observar que, quanto maior o índice periapical radiográfico inicial, pior o prognóstico endodôntico (P < 0.001). Conclusão: O índice de sucesso do tratamento endodôntico foi de 96.7% para casos de polpa vital, 87.5% para os casos de necrose pulpar e 92.9% em retratamentos. Estes índices foram influenciados pelo dente tratado, diagnóstico inicial, índice periapical radiográfico inicial e pelo número de sessões utilizadas no tratamento.

Abstract Introduction and objective: There are still few studies that accurately address endodontic success and which failures actually impact the endodontic treatment outcome. Determine success rate and predictive factors for successful endodontic treatment and retreatment by undergraduate students of the same learning level. Materials and methods: The preservation records (12 months) of the endodontic treatments performed in the Faculty of Dentistry of Pelotas were verified, indicating the success or failure of the treatment. Predictive variables in the outcome of successful endodontic treatment or retreatment were: tooth, number of channels, dental crown, symptoms, pulp diagnosis, radiographic periapical index. The treatmentrelated variables were: instrumentation technique, number of sessions and apical instrumentation limit. Results: 136 endodontic treatments were performed with a follow-up of at least 12 months. The evaluation showed that endodontic success was influenced by the number of sessions (P = 0.015), initial diagnosis and dental group (P = 0.014). It was also observed that the higher the initial radiographic periapical index, the worse the endodontic prognosis (P < 0.001). Conclusion: The success rate of endodontic treatment was 96.7% for cases of vital pulp, 87.5% for cases of pulp necrosis and 92.9% for retreatments. These indices were influenced by type tooth, initial diagnosis, initial radiographic periapical index and the number of visits used in the treatment.

Resumen Introducción y objetivo: Todavía hay pocos estudios que aborden con precisión el éxito endodóntico y cuáles fracasos realmente impactan el resultado del tratamiento endodóntico. Determinar la tasa de éxito y los factores predictivos para el tratamiento y el retratamiento exitoso de endodoncia por estudiantes universitarios del mismo nivel de aprendizaje. Materiales y métodos: Se verificaron los registros de conservación (12 meses) de los tratamientos de endodoncia realizados en la Facultad de Odontología de Pelotas, lo que indica el éxito o el fracaso del tratamiento. Las variables predictivas en el resultado de un tratamiento o retratamiento endodóntico exitoso fueron: diente, número de canales, corona dental, síntomas, diagnóstico pulpar, índice periapical radiográfico. Las variables relacionadas con el tratamiento fueron: técnica de instrumentación, número de sesiones y límite de instrumentación apical. Resultados: se realizaron 136 tratamientos de endodoncia con un seguimiento de al menos 12 meses. La evaluación mostró que el éxito endodóntico estaba influenciado por el número de sesiones (P = 0.015), el diagnóstico inicial y el grupo dental (P = 0.014). También se observó que cuanto mayor es el índice periapical radiográfico inicial, peor es el pronóstico endodóntico (P <0.001). Conclusión: La tasa de éxito del tratamiento endodóntico fue del 96.7% para casos de pulpa vital, 87.5% para casos de necrosis pulpar y 92.9% para retratamientos. Estos índices fueron influenciados por el tipo de diente, el diagnóstico inicial, el índice periapical radiográfico inicial y el número de visitas utilizadas en el tratamiento.

Abstract This study aimed to evaluate the role of photobiomodulation (PBM) in apexification and apexogenesis of necrotic rat molars with an open apex. Rat molars were exposed to the oral environment for 3 weeks. Canals were rinsed with 2.5% NaOCl and 17% EDTA, filled with antibiotic paste and sealed. After 7 days, canals were rinsed and divided into six groups (n=6): mineral trioxide aggregate (MTA); blood clot (BC); human dental pulp stem cells (hDPSC); MTA+PBM; BC+PBM; and hDPSC+PBM. In hDPSC groups, a 1% agarose gel scaffold was used. Two groups were not exposed: healthy tooth+PBM (n = 6), healthy tooth (n = 3); and one was exposed throughout the experiment: necrotic tooth (n = 3). In PBM groups, irradiation was performed with aluminum gallium indium phosphide (InGaAlP) diode laser for 30 days within 24-h intervals. After that, the specimens were processed for histological and immunohistochemical analyses. Necrotic tooth showed greater neutrophil infiltrate (p < 0.05). Necrotic tooth, healthy tooth, and healthy tooth+PBM groups showed absence of a thin layer of fibrous condensation in the periapical area. All the other groups stimulated the formation of a thicker layer of fibers (p < 0.05). All groups formed more mineralized tissue than necrotic tooth (p < 0.05). PBM associated with MTA, BC, or hDPSC formed more mineralized tissue (p < 0.05). MTA+PBM induced apexification (p < 0.05). Rabbit polyclonal anti-bone sialoprotein (BSP) antibody confirmed the histological findings of mineralized tissue formation, and hDPSC groups exhibited higher percentage of BSP-positive cells. It can be concluded that PBM improved apexification and favored apexogenesis in necrotic rat molars with an open apex.

Resumo Este estudo investigou o efeito da contaminação sanguínea na resistência de união do BiodentineTM (BD) e do MTA Angelus® (MTA-A) à dentina, em diferentes períodos. Vinte e cinco dentes foram seccionados para obter 120 fatias de dentina. Os lúmens das fatias foram preenchidos com MTA-A ou BD: 60 para cada cimento (30 não-contaminados e 30 contaminados com sangue). A resistência de união à dentina foi medida por teste push-out em 24 horas (n=10), 7 dias (n=10) e 28 dias (n=10). Os tipos de falha foram classificados como: falha coesiva, adesiva ou mista. Two-way ANOVA foi usado para investigar a interação entre contaminação sanguínea vs. período de hidratação. O teste de Mann Whitney comparou os diferentes materiais em cada período, e comparou as amostras contaminadas e não contaminadas de cada material em cada tempo. O teste de Friedman, seguido pelo teste de Dunn, comparou os períodos de hidratação de cada material, independentemente da contaminação. A análise estatística mostrou a interação entre contaminação sanguínea vs. período de hidratação. Os tipos de falha foram reportados de maneira descritiva. A interação entre contaminação sanguínea vs. período de hidratação foi altamente significativa para o MTA-A (P=0,001), e não foi significativa para o BD (P=0,474). Não houve diferenças entre a resistência de união entre o BD contaminado e não-contaminado independente do período. A resistência de união do MTA-A não-contaminado aumentou a cada tempo de hidratação; mas, permaneceu estável ao longo do tempo para as amostras contaminadas com sangue. BD obteve maior resistência de união que o MTA-A em todos os períodos de hidratação. Falhas coesivas predominaram. A contaminação ao longo do tempo influenciou a resistência de união no grupo MTA-A.

Abstract This study investigated the effect of blood-contamination on the push-out bond strength of BiodentineTM (BD) and MTA Angelus® (MTA-A) to root dentin over time. Twenty-five teeth were sectioned horizontally to obtain 120 root slices. The lumens were filled with MTA-A or BD: 60 for each cement (30 uncontaminated and 30 blood contaminated). Push out bond strength to dentin was assessed at 24 h (n=10), 7 days (n=10) and 28 days (n=10). Failure modes were classified as: cohesive, adhesive or mixed failure. Two-way ANOVA was used to investigate the interaction between blood contamination vs. hydration period. Mann Whitney test compared different materials in each period, and it also compared the contaminated versus uncontaminated material for each period. Friedman, followed by Dunn`s test, compared periods of hydration for each material, regardless of blood contamination. Failure modes were reported descriptively. The interaction hydration period vs. blood contamination was highly significant for MTA-A (P=0.001) and it was not significant for BD (P=0.474). There were no differences between bond strength of uncontaminated and contaminated BD in any of the periods. Bond strength of uncontaminated MTA-A increased at each time of hydration; but it remained stable over time for blood-contaminated samples. BD had higher bond strength than MTA-A in all periods of hydration. Cohesive failure predominated. Only for MTA-A, the over time bond strength to dentin was affected by blood contamination.

Resumo O objetivo deste estudo foi avaliar a extrusão apical de debris durante a desobturação com WaveOne Gold (WOG), ProTaper Universal Retratamento (PTR), D-RaCe (DRR) ou limas manuais (HF), comparar o tempo de trabalho durante a desobturação, e descrever as falhas dos instrumentos de NiTi. Quarenta canais de raízes mésio-vestibulares de primeiros molars superiores foram preparados com WOG Primary, obturados e divididos em 4 grupos (n = 10), de acordo com os instrumentos a serem utilizados: WOG, PTR, DRR ou HF. Água destilada foi utilizada como irrigante, e os debris extruídos foram coletados em tubos Eppendorf e secos. A quantidade de debris extruídos foi determinada subtraindo-se o peso inicial do peso final. O tempo de cada desobturação foi anotado e os instrumentos utilizados foram analisados no pré e pós-operatório em MEV. Os testes Kruskal-Wallis e Dunn foram utilizados para analisar os dados da extrusão de debris, e os testes ANOVA e Tukey para comparar os dados do tempo de trabalho (a=0.05). As deformações e fraturas dos instrumentos foram descritas. O grupo WOG produziu significativamente menos debris quando comparado aos grupos HF e DRR (p<0.05), e foi similar ao grupo PTR (p>0.05). Os grupos HF, PTR e DRR não apresentaram diferença estatisticamente significante (p>0.05). O tempo de trabalho no grupo HF foi significativamente maior do que nos outros grupos (p<0.05). A análise em MEV mostrou que, dos 18 instrumentos avaliados, 3 fraturaram e em 10 foi observado deformação. Todos os sistemas testados causaram extrusão apical de debris. WOG foi associado com menor extrusão do que DRR e HF. A desobturação com HF foi mais lenta do que com os demais instrumentos. Todos os sistemas de NITI apresentaram fratura e deformação.

Abstract The aim of this study was to assess the amount of apically extruded debris during filling removal with WaveOne Gold (WOG), ProTaper Universal Retreatment (PTR), D-RaCe Retreatment (DRR) or hand files (HF), to compare the working time during filling removal, and to describe failures of NiTi instruments. Forty mesiobuccal roots of maxillary first molars were prepared with WOG Primary, obturated and divided into 4 groups (n=10), according to the instruments used: WOG, PTR, DRR or HF. Distilled water was used as irrigant and the extruded debris were collected in Eppendorf tubes and dried. The amount of extruded debris was determined by subtracting the final from the initial weight. The time of filling removal for each canal was recorded and the instruments used were analyzed pre and post-operatively by SEM. Kruskal-Wallis and Dunn’s test analyzed extruded debris data and ANOVA, followed by Tukey’s test, compared the working time data (a=0.05). Instrument deformation and fracture were described. WOG produced significantly less debris compared with HF and DRR (p<0.05), and similar to PTR (p>0.05). HF, PTR and DRR showed no significant difference (p>0.05). Working time in HF group was significantly higher than others (p<0.05). SEM analyses showed, from the 18 instruments evaluated, 3 fractures and 10 deformations. All instruments tested caused debris extrusion. WOG was associated with less extrusion than DRR and HF. Filling removal with HF was slower than with the other instruments. All NiTi systems presented fracture and deformation.

Resumo O objetivo deste estudo foi avaliar a radipacidade de diferentes pontas de guta-percha (Endo Points®, Dentsply®, Tanari®, Meta®, Roeko® e Odous®) em amostras de 1 mm de espessura, conforme estabelecido pela especificação #57 da ANSI/ADA e pela ISO 6876/2001, em comparação com amostras de menor espessura. Doze amostras de cada material, quatro para cada espessura (0,3, 0,6 e 1 mm; 8 mm de diâmetro), foram confeccionadas por meio de laminação e compressão entre duas lâminas de vidro polidas, até a espessura desejada. Radiografias digitais foram obtidas juntamente com uma escala de alumínio graduada, com espessuras variando de 1 a 10 mm. O aparelho de raios X foi ajustado para 70 kVp, 10 mA, 0,4s de tempo de exposição, com distância focal de 36 cm. Um observador calibrado quantificou a média dos valores de pixel no programa Adobe Photoshop®. Os dados foram analisados utilizando os testes ANOVA e Tukey, com nível de significância de 5%. Nas espessuras de 0,6 e 1 mm, todos os materiais testados apresentaram radiopacidade maior do que 3 mm de alumínio (valor de referência). Na espessura de 0,3 mm, Odous e Tanari apresentaram radiopacidade significativamente menor que a referência, e as outras marcas mostraram radiopacidade semelhante à referência. Conclui-se que os materiais apresentaram diferentes radiopacidades e todos mostraram valores acima do mínimo recomendado pela especificação #57 da ANSI/ADA, sendo Odous e Tanari menos radiopacos do que o valor de referência nas amostras mais finas (0.3 mm).

Abstract The aim of this study was to evaluate the radiopacity of different gutta-percha points (Endo Points®, Dentsply®, Tanari®, Meta®, Roeko® and Odous®) in samples of 1 mm thick as established by ANSI/ADA Specification #57 and ISO 6876/2001, in comparison with thinner samples. Twelve test specimens for each material, four for each thickness (0.3, 0.6, and 1 mm and diameter of 8 mm), were laminated and compressed between two polished glass plates until the desirable thickness. Digital radiographs were obtained along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The X-ray unit was set at 70 kVp, 10 mA and 0.4 s exposure time, at a focal distance of 36 cm. One calibrated observer quantified the average values of pixels with Adobe Photoshop® software. Data were analyzed using ANOVA and Tukey tests, at 5% significance level. At 0.6 and 1 mm thickness, all the tested materials showed radiopacity higher than 3 mm of aluminum (reference value). At 0.3 mm thickness, Odous and Tanari presented significantly less radiopacity than the reference, and the other materials showed similar radiopacity to the reference. The study concluded that the materials demonstrated different radiopacities and all had values above the minimum recommended by ANSI/ADA specification #57, being Odous and Tanari less radiopaque than the reference value in thinner samples (0.3mm).

Abstract This study aimed to evaluate the effect of final irrigation protocols on microhardness reduction and erosion of root canal dentin. Sixty root canals from mandibular incisors were instrumented and randomly divided into six groups (n = 10) according to the irrigant used: QMiX, 17% EDTA, 10% citric acid (CA), 1% peracetic acid (PA), 2.5% NaOCl (solution control), and distilled water (negative control). The chelating solutions were used to irrigate the canal followed by 2.5% NaOCl as a final flush. After the irrigation protocols, all specimens were rinsed with 10 mL of distilled water to remove any residue of the chemical solutions. Before and after the final irrigation protocols, dentin microhardness was measured with a Knoop indenter. Three indentations were made at 100 µm and 500 µm from the root canal lumen. Afterwards, the specimens were prepared for scanning electron microscopic analysis and the amount of dentin erosion was examined. Wilcoxon and Kruskal-Wallis tests were used to analyze the results with a significance level set at 5%. At 100 µm, all protocols significantly reduced dentin microhardness (p < .05), while at 500 µm, this effect was detected only in the EDTA and QMiX groups (p < .05). CA was the irrigant that caused more extensive erosion in dentinal tubules, followed by PA and EDTA. QMiX opened dentinal tubules, but did not cause dentin erosion. Results suggest that QMiX and 17% EDTA reduced dentin microhardness at a greater depth. Additionally, QMiX did not cause dentin erosion.

Resumo Um dos requisistos para a aplicação clínica de materiais endodônticos é apresentar comportamento biológico satisfatório. Neste estudo, as respostas do tecido conjuntivo a cimentos endodônticos à base de silicone (GuttaFlow 2), resina epóxica (AH Plus) e óxido de zinco e eugenol (Endofill) foram comparadas. Doze ratos Wistar tiveram tubos de polietileno (4 em cada animal) contendo um dos materiais e tubos vazios (controle negativo) implantados no tecido conjuntivo subcutâneo. Os tubos foram randomicamente posicionados pelo menos 2 cm distantes entre si e da espinha dorsal do animal. Amostras de tecido contendo os implantes foram processadas para análise histológica após 7 e 60 dias (n=6 animais por período). Células inflamatórias, condensação fibrosa e formação de abscesso foram classificadas em escores de acordo com sua intensidade. O teste Friedman, seguido por post hoc de Dunn, foi empregado para comparar os cimentos. O teste de Mann-Witney U foi empregado para verificar diferenças entre os períodos experimentais em cada grupo (p<0,05). Após 7 dias, a maior parte dos parâmetros histológicos não mostrou diferenças estatísticas entre os grupos. O cimento Endofill promoveu escores mais altos que os outros materiais para a variável células gigantes (p<0,05), além de apresentar um maior número de amostras com formação de abscesso. O GuttaFlow 2 tendeu a apresentar infiltrado inflamatório menos intenso comparado aos outros materiais. Após 60 dias, não houve diferenças estatisticamente significantes entre os grupos na maioria dos parâmetros avaliados. Entretanto, observou-se que o EndoFill apresentou escores mais altos para os macrófagos em comparação ao controle (p<0,05) e que o GuttaFlow 2 apresentou tendência a escores mais baixos que os demais materiais para as variáveis neutrófilos e abscesso. O GuttaFlow 2 apresentou propriedades biológicas apropriadas e pode ser considerado adequado para a prática clínica.

Abstract Satisfactory biological behavior is a necessary requirement for clinical application of endodontic materials. In this study, the connective tissue responses to silicone (GuttaFlow 2), epoxy resin (AH Plus) and zinc oxide and eugenol (Endofill) based sealers were compared. Twelve Wistar rats had polyethylene tubes (four per animal) containing one of the tested sealers and empty tubes (negative control) implanted in their subcutaneous tissue. The tubes were randomly placed 2 cm from the spine and at least 2 cm apart from one another. Tissue samples with implants were processed for histological analysis after 7 or 60 days (n=6 animals per period). Inflammatory cells, fibrous condensation and abscess were scored according to their intensity. Friedman, followed by Dunn's post hoc, was used to compare sealers. Differences between the two experimental periods were verified using Mann-Witney U test (p<0.05). At 7 days, most of the histological parameters showed no significant differences amongst groups. Endofill group scored higher than the others for giant cells (o<0.05) and promoted a greater number of samples presenting abscess formation. GuttaFlow 2 tended to show a less intense inflammatory infiltrate compared to the other materials. At 60 days, there were no significant differences between groups in most of the histological parameters evaluated. However, it was observed that Endofill scored higher for macrophages (p<0.05) compared to the control group, and GuttaFlow 2 tended to present lower scores than the others for neutrophils and abscess. GuttaFlow 2 showed proper biological behavior and should be considered adequate for clinical practice.