Effect of different disinfection protocols in bacterial viability of an intraradicular biofilm formed in situ

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.

Impact of COVID-19 pandemic on completed treatments and referrals during urgent dental visits

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.

Physicochemical properties of three bioceramic cements

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.

XP Endo Finisher-R and PUI as supplementary methods to remove root filling materials from curved canals

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.

Periodontite apical assintomática com rompimento de cortical óssea em paciente sob tratamento contínuo com isotretinoína: relato de caso / Asymptomatic apical periodontitis with cortical bone disruption in patient under continuous treatment with Isotretinoin: case report

Introdução: A periodontite apical assintomática (PAA) é caracterizada pela inflamação e destruição dos tecidos periapicais, e sua progressão promove reabsorção óssea, podendo ser agravada pelo uso contínuo de isotretinoína. Objetivo: O objetivo do presente estudo foi relatar a resolução de uma PAA com rompimento de cortical óssea mandibular em um paciente sob tratamento contínuo com isotretinoína (Roacutan®), por meio de procedimentos químicos-mecânicos convencionais e controle com tomografia computadorizada de feixe cônico (TCFC). Descrição: Um paciente com 21 anos de idade, ASA I, em tratamento contínuo com isotretinoína, procurou atendimento odontológico com moderada dor na região do elemento dental #38. Após exames clínicos, radiográficos e tomográficos, verificou-se a necessidade de tratamento endodôntico do dente #36. A TCFC mostrou uma imagem apical extensa e hipodensa entre os dentes #36 e #37, compatível com lesão cística óssea, com dimensões de 25,59 mm (largura) x 14,37 mm (altura) x 8,40 mm (profundidade). Também foram observados reabsorção apical da raiz distal, halo hipodenso sob a restauração coronal do #36 e ruptura da cortical externa vestibular e lingual. O tratamento endodôntico foi realizado em três sessões, com auxílio de um microscópio operatório e protocolos químicos-mecânicos, como Easy Clean e terapia fotodinâmica. Resultado: A resolução da PAA foi observada após acompanhamento por três anos. Conclusão: O tratamento endodôntico permitiu o reparo de uma lesão periapical extensa, evitando a cirurgia parendodôntica imediata, e o uso contínuo de isotretinoína não afetou a resolução da PAA(AU).

Introduction: Asymptomatic apical periodontitis (AAP) is characterized by inflammation and destruction of the periapical tissues and its progression leads to bone resorption, which may be aggravated by continuous use of Isotretinoin. The objective of this study was to report the resolution of AAP with mandibular cortical disruption in a patient under continuous treatment with isotretinoin (Roacutan®) and kickboxing practitioner, by conventional chemical-mechanical procedures and cone-bean computed tomography (CBCT) follow-up. Description: A 21-year-old Caucasoid individual, ASA I, under continuous use of isotretinoin and kickboxing practitioner sought dental care with moderate pain at the region of tooth #38. After clinical, radiographic and tomographic examination, the need for endodontic treatment of tooth #36 was verified. The CBCT showed an extensive and hypodense apical image between teeth #36 and #37, compatible with cystic bone lesion, with dimensions of 25.59 mm wide x 14.37 mm high x 8.40 mm deep. Apical resorption of the distal root, hypodense halo under a coronal restoration at #36, and rupture of the external buccal and lingual cortical bone were also observed. The endodontic treatment was performed in three sessions with the aid of a microscope and chemical-mechanical protocols, such as Easy Clean and photodynamic therapy. Result: Resolution of AAP was observed after follow-up for three years. Conclusion: Endodontic treatment allowed healing of an extensive periapical lesion, avoiding immediate parendodontic surgery and the continuous use of isotretinoin did not affect the AAP resolution. (AU).

Marginal gaps and internal voids after root-end filling using three calcium silicate-based materials: A Micro-CT analysis

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.

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.

Root canal retreatment: a retrospective investigation using regression and data mining methods for the prediction of technical quality and periapical healing

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.

Influence of photobiomodulation therapy on root development of rat molars with open apex and pulp necrosis

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.

Effect of blood contamination on the push-out bond strength of calcium silicate cements

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 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.

Apically extruded debris in filling removal of curved canals using 3 NiTi systems and hand files

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 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.

Radiopacity Evaluation of Gutta-Percha Points in Thinner Samples than the ANSI/ADA Recommendation

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).

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).

Effect of final irrigation protocols on microhardness reduction and erosion of root canal dentin

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.

Biological Tissue Response to a New Formulation of a Silicone Based Endodontic Sealer

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.

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.

Effectiveness of hand and Mtwo TM Instruments in preparing oval-shaped root canals: in vitro study

Objective: This study evaluated through stereomicroscopy the effectiveness of hand and rotary instrumentation techniques, either isolated or combined, in the preparation of oval-shaped root canals. Materials and method: Thirty single-rooted human mandibular incisors were selected. After endodontic access and coronal preflaring, teeth were mounted in a modified Bramante muffle and then sectioned transversely at 3 and 6 mm from the root apex. Images of each section were made under a stereomicroscope at 30× magnification. Teeth were reassembled in the muffle and divided into three groups (n=10) according to the root canal preparation technique: GI - rotary preparation with Mtwo™ basic sequence (10/.04; 15/.05; 20/.06; 25/.06), followed by Mtwo™ complementary instruments (30/.05; 35/.04; 40/.04); GII - rotary preparation with Mtwo™ basic sequence, complemented by hand instruments (#30, #35 and #40); GIII - hand instrumentation using the conventional technique (#10 to #40). All instruments were used in brushing motion. The muffles were separated again so that new images of each section could be obtained. The following parameters were evaluated in pre- and postoperative images: root canal area; perimeter; mesiodistal (MD) and buccolingual (BL) diameters; and mesial (M) and distal (D) wall thickness. Next, the values measured in post- and preoperative images were subtracted for comparison of experimental groups. Data were analyzed using the Kruskal-Wallis test (α=0.05). Results: No significant difference between groups was observed for all parameters. Conclusion: There was no difference among hand, rotary, or combined instrumentation; all techniques were able to increase root canal area, perimeter, and diameter in MD and BL directions. Moreover, the amount of dentin wear on proximal root canal walls was similar for all tested groups. Keywords: Endodontics. Microscopy. Root canal preparation. Root canal therapy. Stereomicroscopy.

Shaping ability of rotatory or reciprocating instruments in curved canals: a micro-computed tomographic study

Abstract This study aimed to compare apical transportation, centering ratio, and working time during root canal preparation with Wizard Navigator (WN), WaveOne (WO), or ProTaper Universal (PT) and to describe deformation and fracture of these instruments. Thirty-six mesiobuccal roots from maxillary molars were micro-computed tomography (micro-CT) scanned and then sorted into three groups (n = 12): Wizard Navigator (WN), WaveOne (WO), and ProTaper Universal (PT). The root canals were prepared using WN, WO, or PT; the time of each canal preparation was timed; and the specimens were micro-CT re-scanned. The instruments were submitted to scanning electron microscopy (SEM) before and after their use. The data on canal transportation at 1, 2, 3, 4 and 5 mm and preparation time were analyzed by the Kruskal-Wallis test, followed by the Mann-Whitney U test. The centering ratio was analyzed by ANOVA, followed by Tukey's test. Both instrument deformation and fracture were described. Apical transportation was similar among groups at 1, 2, 3 and 4 mm. The WO group showed higher canal transportation at 5mm than the other groups (p = 0.03). There was no significant difference in centering ratio among the groups. Preparation time in the WO group was significantly lower than in the other groups (p = 0.004). Small differences were observed in the surface area of all instruments. The WN, WO, and PT groups had a similar centering ratio without procedural errors or significant structural changes. At 5 mm from the apex, the WO group showed the largest canal transportation toward the furcation and root canal preparation was faster than in the WN and PT groups.

Effect of Different Irrigating Solutions and Photo-Activated Therapy for In Vivo Root Canal Treatment

This study aimed to evaluate histologically the effect of irrigation with 400 ppm Sterilox, 2% and 5% sodium hypochlorite (NaOCl), with and without photo-activated therapy (PAD), in a single-visit root canal treatment of dog's teeth with apical periodontitis (AP). Ten dogs were randomly divided into two groups (n=5): with and without PAD, and the root canals into four subgroups, according to the irrigating solution: SX (400 ppm Sterilox), SH2 (2% NaOCl), SH5 (5% NaOCl) and SS (saline solution) as positive control. A total of 134 root canals were opened and left exposed to the oral environment for 14 days and then sealed for 60 days for AP induction. Then, root canals were treated according to each proposed disinfecting protocol and filled in the same session. After 120 days, the dogs were euthanized and the periapical inflammatory events were evaluated under light microscopy. Qualitative data were submitted to Kruskal-Wallis and Mann-Whitney tests (α=0.05). PAD did not produce significant differences in the scores for apical inflammation when used after chemo-mechanical preparation (p>0.05). The irrigating solutions SX, SH2 and SH5 without PAD were statistically different from SS (p<0.05) that presented the greatest scores for apical inflammation. PAD did not show any additional effect for the treatment of root canals with pulp necrosis and AP in a single visit and 400 ppm Sterilox may be considered an alternative to NaOCl in root canal treatment.

Este estudo realizou uma avaliação histológica do efeito das soluções irrigadoras Sterilox 400 ppm e hipoclorito de sódio (NaOCl) a 2% e 5%, com e sem a terapia fotodinâmica (PAD), na endodontia em sessão única de dentes de cães associados a lesões periapicais (APs). Dez cães foram divididos de forma randomizada em dois grupos (n=5): com e sem PAD, e os canais radiculares em quatro subgrupos, de acordo com a solução irrigadora utilizada: SX (Sterilox 400 ppm), SH2 (NaOCl 2%), SH5 (NaOCl 5%) e SS (solução salina) como controle positivo. Cento e trinta e quatro canais foram abertos e deixados expostos ao meio oral por 14 dias e depois selados por 60 dias para a indução de APs. Na sequência, os canais foram tratados de acordo com cada protocolo de desinfecção proposto e obturados na mesma sessão. Após 120 dias, os cães foram mortos e os eventos inflamatórios periapicais foram avaliados em microscopia óptica. Os dados qualitativos foram analisados estatisticamente pelos testes Kruskal-Wallis e Mann-Whitney (α=0,05). A PAD, quando empregada após o preparo químico-mecânico, não promoveu diferenças significativas nos escores para inflamação apical (p>0,05). As soluções irrigadoras SX, SH2 e SH5 sem PAD apresentaram diferenças estatísticas do grupo SS (p<0,05) que apresentou os maiores escores para inflamação apical. A PAD não apresentou efeito adicional na endodontia em sessão única dos canais com necrose pulpar associados a lesão apical e a solução irrigadora Sterilox 400 ppm pode ser considerada uma alternativa ao NaOCl na terapia endodôntica.

Evaluation of the in vitro antimicrobial activity of alcoholic solution and aqueous extract of bee propolis against enterococcus faecalis

AIM: The purpose of this study was to analyze the in vitro antimicrobial activity of aqueous and alcoholic extracts of propolis at 1% and 3% concentrations against Enterococcus faecalis (ATCC® 19433). MATERIAL AND METHODS: Initially, the microbial suspension was seeded in a Brain Heart Infusion Agar (BHIA) culture medium, distributed in 20 Petri dishes. Then, 4 soaked filter paper discs were placed on the surface of the inoculated medium of each plate for 1 minute in 1 mL of the following substances: C+ (positive control, n=20): 2% chlorhexidine gel; C- (negative control, n=20): saline solution; S1 (n=10): 1% bee propolis alcoholic solution; S2 (n=10): 3% bee propolis alcoholic solution; E1 (n=10): 1% aqueous propolis extract; E2 (n=10): 3% aqueous propolis extract. One filter paper disc of each (C+, C-, S1 and S2) was placed in a set of 10 Petri dishes, whereas one filter paper disc of each (C+, C-, E1 and E2) was placed in the other set of 10 Petri dishes. RESULTS: The results obtained after incubation at 37°C for 24 hours under microaerobic conditions revealed that S2 showed higher mean levels of microbial growth inhibition as compared to E1, E2 and S1. There were no significantly statically differences between the groups, except for the S2 group and C- group. Mean levels in all other groups were lower than in the C+ group. CONCLUSION: The study concluded that 1% and 3% bee propolis alcoholic solution had lower antibacterial activity against Enterococcus faecalis as compared to 2% chlorhexidine gel.

Effect of Super-Oxidized Water, Sodium Hypochlorite and EDTA on Dentin Microhardness

The present study aimed to evaluate the influence of the following irrigating solutions on the microhardness of root canal dentin: 2% sodium hypochlorite (2NaOCl), 5% sodium hypochlorite (5NaOCl), super-oxidized water (400 ppm Sterilox - Sx) and 17% EDTA (E). Eighty roots from bovine incisors were randomly divided into 8 groups (n=10): 2NaOCl, 5NaOCl, Sx, and 2NaOCl + E, 5NaOCl + E, Sx + E (associated with E as final irrigant for 5 min), E solely and distilled water (dH2O) as the negative control. Root canal preparation was performed by hand instruments, using one of the irrigation protocols for 30 min. Then, 5 mm of the cervical root third were cut out from each sample and subjected to the Vickers microhardness test, at two points, one at approximately 500-1000 µm from the root canal lumen (distance 1), and the other at approximately 500-1000 µm from the external root surface (distance 2). Data were analyzed by Wilcoxon and Kruskal-Wallis tests at 5% significance level. Microhardness values at distance 1 were significantly lower than those at distance 2 for all groups, except 5NaOCl and 5NaOCl + E groups (p>0.05). EDTA showed the lowest microhardness values. However, no statistically significant difference was detected among groups at distance 1 and EDTA was significantly different only from Sx at distance 2. In conclusion, all tested solutions showed lower microhardness at the most superficial root canal dentin layer compared to the one found near the external root surface, except 5NaOCl and 5NaOCl + E; EDTA promoted lower microhardness values in comparison to Sterilox at this site.

O presente estudo teve como objetivo avaliar a influência das seguintes soluções irrigadoras na microdureza da dentina do canal radicular: hipoclorito de sódio a 2% (NaOCl2), hipoclorito de sódio a 5% (NaOCl5), água superoxidada (Sterilox(r) 400 ppm - Sx) e EDTA a 17% (E). Oitenta raízes de incisivos bovinos foram divididas aleatoriamente em 8 grupos (n=10): NaOCl2, NaOCl5, Sx e NaOCl2 + E, NaOCl5 + E, Sx + E (associados ao E como irrigante final por 5 min), E isolado e água destilada (H2Od), como controle negativo. O preparo dos canais radiculares foi realizado com instrumentos manuais, usando um dos protocolos de irrigação por 30 min. A seguir, 5 mm do terço cervical de cada amostra foram cortados perpendicularmente e submetidos ao teste de microdureza de Vickers, em dois pontos, um aproximadamente 500-1000 µm da luz do canal radicular (distância 1), e o outro aproximadamente 500-1000 µm da superfície externa da raiz (distância 2). Os dados foram analisados pelos testes de Wilcoxon e Kruskal-Wallis com um nível de significância de 5%. Os valores de microdureza na distância 1 foram significativamente menores do que na distância 2 para todos os grupos, exceto NaOCl5 e NaOCl5 +E (p>0,05). O EDTA mostrou os menores valores de microdureza. No entanto, não foi detectada diferença estatisticamente significativa entre os grupos na distância 1 e o EDTA foi significativamente diferente apenas do Sx na distância 2. Pode-se concluir que todas as soluções testadas mostraram menor microdureza na camada de dentina mais superficial do canal radicular em comparação aos valores encontrados próximo à superfície radicular externa, exceto NaOCl5 e NaOCl5 + E; o EDTA promoveu menor microdureza em comparação ao Sterilox(r) neste ponto.

The impact of the addition of iodoform on the physicochemical properties of an epoxy-based endodontic sealer

Due to the low radiopacity of Sealer 26, iodoform is frequently empirically added to this sealer. Thus, the interference of this procedure with the physicochemical properties of Sealer 26 must be evaluated. Objective: This study evaluated the influence of the addition of iodoform on setting time, flow, solubility, pH, and calcium release of an epoxy-based sealer. Material and Methods: The control group was pure Sealer 26, and the experimental groups were Sealer 26 added with 1.1 g, 0.55 g or 0.275 g of iodoform. Setting time evaluation was performed in accordance with the ASTM C266-03 speciflcation. The analysis of flow and solubility was in accordance with the ISO 6876-2001 speciflcation. For the evaluation of pH and calcium ion release, polyethylene tubes were filled with the materials and immersed in flasks with 10 ml of deionized water. After 24 h, 7, 14, 21, 28, and 45 days pH was measured. In 45 days, the calcium released was evaluated with an atomic absorption spectrophotometer. Results: The addition of iodoform increased setting time in comparison with pure sealer (P<0.05). As for flow, solubility, and calcium release, the mixtures presented results similar to pure sealer (p>0.05). In the 24 h period, the mixture with 1.1 g and 0.55 g of iodoform showed lower pH than pure sealer and than sealer added with 0.275 g of iodoform (P<0.05). Conclusions: The iodoform added to Sealer 26 interferes with its setting time and solubility properties. Further studies are needed to address the clinical signiflcance of this interference. .

Dissolução de cimentos endodônticos resinosos por solventes orgânicos em diferentes intervalos de tempo / Dissolution of resin-based root canal sealers by organic solvents at different time intervals

Objetivo: O objetivo deste estudo foi investigar se o tempo deexposição dos cimentos endodônticos resinosos a solventesorgânicos afeta sua solubilidade. Materiais e métodos: Moldes desilicona de condensação circulares padronizados (4,47 mm de largurapor 1,5 mm de altura) foram preenchidos com quatro cimentosendodônticos resinosos recém-misturados (Acroseal®, Epiphany®, AHPlus® e Sealer26®) e armazenados a 37°C por duas semanas (n=08).Depois de inspecionado, cada corpo-de-prova foi pesado três vezes eindividualmente imerso em Citrol®, Endosolv R®, hipoclorito de sódio a2,5% ou água destilada (controle) por 10 minutos, 02 horas e 24horas. Nos intervalos testados, a perda média de cada materialobturador imerso nos solventes foi determinada. Os dados foramanalisados estatisticamente com ANOVA de duas vias, Bonferronipost hoc e teste de Pearson (α=0,05). Resultados: O Endosolv R® foisignificativamente mais eficiente na dissolução do Sealer26® do que aágua destilada (grupo controle), óleo de laranjas e hipoclorito desódio 2,5%. O Citrol® e o hipoclorito de sódio 2,5% demonstrarammaior potencial para dissolver o cimento Sealer26® no intervalo de 24horas, quando comparados ao grupo controle. As diferenças de peso entre os cimentos imersos em hipoclorito de sódio 2,5% não semostraram estatisticamente significantes. A solubilidade foisignificativamente correlacionada com o tempo de exposição somentequando o Endosolv R® (+0,829) ou a água destilada (+0,441) foramempregados. Conclusão: A dissolução de cimentos à base de resinafoi afetada pelo intervalo de exposição e tipo de solvente orgânicoutilizado. Endosolv R® e períodos mais longos de exposiçãopromoveram maior solubilização dos cimentos de base resinosa testados.

Aim: The aim of this study was to investigate whether time exposureof resin-based root canal sealers to organic solvents affects theirsolubility. Materials and methods: Standardized circular siliconmoulds (4.47mm wide and 1.5mm high) were filled with four freshlymixed resin-based root canal sealers (Acroseal®, Epiphany®, AHPlus® and Sealer 26®) and stored at 37° for two weeks (n=8). Afterinspection, each sample was weighted thrice and individuallyimmersed in Citrol®, Endosolv R®, 2.5% sodium hypochlorite ordistilled water for 10, 120 and 1440 min. In the tested intervals, themean weight loss of each filling material immersed in solvents wasdetermined. Data were statistically analyzed by Two-wayANOVA, Bonferroni post hoc and Pearson tests (α=0.05). Results:Endosolv ® R was significantly more effective in dissolving Sealer26 ®than distilled water (control group), orange oil and 2.5% sodiumhypochlorite. Citrol® and 2.5% sodium hypochlorite showed thegreatest potential to dissolve Sealer26 ® within 24 hours, compared tothe control group. The weight losses between sealers immersed insodium hypochlorite 2.5% were not statistically significant. Solubilitywas significantly correlated with exposure intervals only whenEndosolv R® (+0,829) or double-distilled water (+0,441) wereapplied. Conclusion: Dissolution of resin-based root canal sealerswas affected by exposure interval and type of organic solvent used.Endosolv R® and longer exposure intervals promoted greatersolubilization of the resin-based sealers tested.