Effect of the timing of primary endodontic treatment and dosage of radiation therapy on the filling material removal.

This study investigated the effect of the timing of primary endodontic treatment and dosage of radiotherapy on the remaining filling material (RFM) during endodontic reintervention. 60 single-rooted human mandibular premolars were distributed into five groups (n = 12), according to the timing and dosage of radiation (55Gy or 70Gy): NegativeCG-non-irradiated teeth; Endo-pre-RT55/70-obturation before irradiation (55Gy or 70Gy); Endo-post-RT55/70-obturation and reintervention after irradiation (55Gy or 70Gy). Roots were cleaved and analysed under stereomicroscope and Scanning Electron Microscope to quantify (%) the RFM. Experimental groups had a significantly greater amount (p < 0.05) of RFM in the middle and apical thirds than the control group, except for Endo-pre-RT55 in the middle third (p < 0.0001). The apical third had greater amount of RFM (p < 0.05). Radiation therapy, before and after primary endodontic treatment, increased the amount of RFM, regardless of the dose delivered. When necessary, reintervention preferably must be performed before radiation therapy.

Assessing push-out bond strength in re-irradiated teeth: Universal resin cement performance in self-etch and self-adhesive modes.

OBJECTIVES: To investigate the effect of cumulative doses of radiation on the pushout bond strength (BS) of a universal resin cement used in the self-etch (SE) and self-adhesive (SA) modes to the intraradicular dentin. MATERIALS AND METHODS: Forty-eight human teeth were distributed into three groups (n = 16) according to the radiation therapy dose (RT): NoRT (no-radiotherapy), 70RT (70 Gy), and 70 + 70RT (70 Gy + 70 Gy). The teeth were redistributed into two subgroups (n = 8), according to the adhesive mode: SE (NoRT-SE, 70RT-SE, and 70 + 70RT-SE) and SA (NoRT-SA, 70RT-SA, and 70 + 70RT-SA). Data were statistically compared after BS test (ANOVA, Tukey's post hoc test, and Fisher's exact test). RESULTS: In the SA mode, BS was significantly higher in nonirradiated teeth compared with 70RT and 70 + 70RT (p < 0.0001). There were no significant differences between SE and SA modes in nonirradiated teeth (p = 0.14). In the 70RT group, SE mode increased BS compared with SA mode (p < 0.0001). Most specimens had adhesive and mixed failures in SA and SE modes, respectively. CONCLUSIONS: The universal resin cement in the SE mode had greater BS to the irradiated dentin. When teeth were re-irradiated, the universal resin cement had similar performance in terms of BS, regardless of the adhesive approach. CLINICAL SIGNIFICANCE: There is no research establishing a correlation between radiotherapy and its impact on the BS of a universal resin cement used in SE and SA modes to intraradicular dentin.

Effect of radiation therapy on fracture resistance of simulated immature teeth submitted to root reinforcement.

BACKGROUND: The literature is scanty regarding the effect of radiation therapy (RT) on the mechanical properties of immature permanent teeth. AIM: To evaluate the effect of RT on the fracture resistance of simulated immature teeth submitted to different types of root reinforcement. DESIGN: Sixty-four human teeth simulating the Cvek stage 3 of root development were distributed into eight groups (n = 8), according to exposure or not to RT (70 Gy) and the root reinforcement method: Group NR (control)-no reinforcement/no RT; Group NR + RT (control)-no reinforcement/RT; Group PO-tricalcium silicate-based cement (TS) apical plug/canal obturation/no RT; Group PO + RT-TS apical plug/canal obturation/RT; Group TS-canal filling with TS/no RT; Group TS + RT-canal filling with TS/RT; Group FP-TS apical plug/fibreglass post/no RT; and Group FP + RT-TS apical plug/fibreglass post/RT. Fracture resistance was determined using a universal testing machine (0.5 mm/min). RESULTS: In the intergroup comparison, nonirradiated teeth had higher fracture resistance (p < .05). Groups FP and FP + RT had higher fracture resistance (p < .001). CONCLUSION: Radiotherapy affected the fracture resistance of simulated immature teeth. Reinforcement with fibreglass posts increased the fracture resistance, regardless of the radiation.

The effects of heating on the physicochemical properties of tricalcium silicate root canal sealers

Abstract This study evaluated the effect of heating on the physicochemical properties and surface changes of tricalcium silicate sealers. Three tricalcium silicate root canal sealers (Bio-C Sealer, BioRoot-RCS, EndoSequence BC Sealer), and one epoxy resin-based sealer (AH Plus; control) were tested. The effect of heating on setting time (ST) and flowability were assessed according to ANSI/ADA 57 and ISO 6876 standards. Solubility and dimensional change (DC) of the set sealers were evaluated at 24 hours and after 30 days; the pH of the water used in the DC testing was also measured. Tests were repeated with heated sealers in an oven at 100 °C for 1 min. SEM and EDS analysis were performed. Data were analyzed using One-Way ANOVA and Tukey post-hoc tests (α=5%). Heating decreased the ST for AH Plus and EndoSequence (p<0.05). Heating reduced flowability (p<0.05) and increased pH for AH Plus (p<0.05). The solubility of Bio-C (dried specimens) was not in accordance with the ANSI/ADA standard. The solubility of EndoSequence was significantly higher (p<0.05) when it was heated and dried after 30 days. DC of Bio-C (24 h and 30 days), BioRoot-RCS (30 days) and AH Plus (24 h and 30 days) were not in accordance with the standards. SEM and EDS analysis showed significant changes in sealer microstructure after heating. In conclusion, heating decreased the ST and increased the solubility of EndoSequence BC sealer. No significant changes in flowability, DC, and pH were identified for all three tricalcium silicate sealers after heat application. However, all sealers had significant surface changes.

Resumo Este estudo avaliou o efeito do aquecimento nas propriedades físico-químicas e nas alterações superficiais de cimentos de silicato tricálcico. Três cimentos endodônticos de silicato tricálcico (Bio-C Sealer, BioRoot-RCS, EndoSequence BC Sealer) e um cimento à base de resina epóxi (AH Plus) foram testados para avaliar o efeito do aquecimento no tempo de presa (TP) e escoamento de acordo com as normas ANSI/ADA 57 e ISO 6876. A solubilidade e alteração dimensional (AD) dos cimentos foram avaliadas após 24 horas e 30 dias. O pH da água usada no teste de AD também foi medido. Os testes foram repetidos com cimentos aquecidos em um forno a 100 °C por 1 min. Análises em MEV e EDS foram realizadas. Os dados foram analisados pelos testes de ANOVA-1 via e post hoc de Tukey (α=5%). O aquecimento diminuiu o TP para AH Plus e EndoSequence (p<0,05). O aquecimento reduziu o escoamento (p<0,05) e aumentou o pH do AH Plus (p<0,05). A solubilidade do Bio-C (amostras desidratadas) não estava de acordo com o padrão ANSI/ADA. A solubilidade da EndoSequence foi significativamente maior (p<0,05) quando aquecida e desidratada após 30 dias. As AD de Bio-C (24 h e 30 dias), BioRoot-RCS (30 dias) e AH Plus (24 h e 30 dias) não estavam de acordo com as normas ADA e ISO. A análise em MEV e EDS mostrou alterações significativas na estrutura dos cimentos após aquecimento. Em conclusão, o aquecimento diminuiu o TP e aumentou a solubilidade do cimento EndoSequence BC. Não foram identificadas mudanças significativas no escoamento, AD e pH para os cimentos de silicato tricálcico após aquecimento. Porém, todos os cimentos tiveram alterações significativas na superfície.

Effect of the timing of radiation therapy on the push-out strength of resin cement to root dentine.

This study investigated the effect of radiation timing on the bond strength of resin cement to intraradicular dentine. Fifty human teeth were distributed into 5 groups (n = 10): Control (nonirradiated teeth), Before-RCT (teeth irradiated before root canal treatment), After-CH (teeth irradiated after canal preparation and placement of calcium hydroxide intracanal dressing), After-RCT (teeth irradiated after completion of root canal treatment) and After-FPL (teeth irradiated after luting of a glass fibre post). Each tooth received 70 Gy irradiation. The roots were sectioned for push-out strength testing. After-RCT and After-FPL groups had significantly lower push-out strength than the control at the middle third (p < 0.05). Control and After-CH groups had a higher percentage of cohesive dentine failure. Radiotherapy after root canal obturation and post luting adversely affected the adhesiveness of resin cement to intraradicular dentine. Teeth irradiated before root canal treatment and after placement of calcium hydroxide had the best performance.

Dental and composite resin discoloration induced by different hydraulic calcium silicate-based cements: two-year in vitro assessment

Abstract Few long-term studies assess the discoloration induced by hydraulic calcium silicate-based cement on dental structures. In addition, as far as we know, no long-term study has assessed the discoloration induced by these cement on composite resin. Objective This in vitro study aimed to assess, during a period of two years, the discoloration potential of different hydraulic calcium silicate-based cements (hCSCs) on the enamel/dentin structure and composite resin restoration. Methodology A total of 40 enamel/dentin discs were obtained from bovine incisors, and 40 composite resin discs (10 mm in diameter × 2 mm thick) were fabricated. A 0.8 mm-deep cavity was made in the center of each disc and filled with the following hCSCs (n=10): Original MTA (Angelus); MTA Repair HP (Angelus); NeoMTA Plus (Avalon); and Biodentine (Septodont). An initial color measurement was performed (T0 - baseline). After 7, 15, 30, 45, 90, 300 days, and two years, new color measurements were performed to determine the color (ΔE00), lightness (ΔL'), chroma (ΔC'), hue differences (ΔH'), and whiteness index (WID). Results For enamel/dentin, the ΔE00 was significant among groups and periods (p<0.05). NeoMTA Plus had the greatest ΔE00. The NeoMTA Plus group had the greatest ΔE00 after two years for composite resin. Significant reduction in lightness was observed for all groups after two years (p<0.05). The most significant WID values were observed after 30 days for Biodentine (enamel/dentin) and MTA Repair HP groups (composite resin) (p<0.05). Conclusions The hCSCs changed the colorimetric behavior of both substrates, leading to greater darkening over time. The Bi2O3 in the Original MTA seems relevant in the short periods of color change assessment.

Effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots / Efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar raíces debilitadas

Background: This study evaluated the effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots. Material and Methods: Sixty-four roots of extracted human maxillary canines were weakened, prepared and filled with two different endodontic sealers (Endofill and AH Plus). In half of the sample, set aside for each respective sealer, excess filling material was cleaned. In the other half, the weakened areas were not cleaned, and the excess of sealer was spread on the intraradicular dentin. Intentionally worn areas inside each root were restored with a microhybrid light-cure composite resin (Z100) to reinforce them, with and without acid etching. Prefabricated metal posts were fixed with a dual resin cement (RelyX ARC), and the specimens were submitted to a pull-out test. Statistical analysis was performed by means of Shapiro-Wilk, analysis of variance (one-way ANOVA) and Tukey-Kramer tests (p<0.05). Results: The groups filled with Endofill (GI, GII, GIII, GIV) had the lowest bond strength values, which were similar among each other (p>0.05).The greatest bond strength values were observed in roots filled with AH Plus (GV, GVI, GVII, GVIII), mainly without cleaning of the weakened areas, and followed by acid etching (GVII), and also with cleaning of the weakened areas, however, with no acid etching (GVI) (p<0.05). Conclusion: The greatest bond strength values were observed in roots filled with AH Plus; (1) without cleaning of the weakened areas and with acid etching, and; (2) with cleaning of the weakened areas, but without acid etching.

Antecedentes: este estudio evaluó los efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar las raíces debilitadas. Material y Métodos: Sesenta y cuatro raíces de caninos maxilares humanos extraídos fueron debilitadas, preparadas y rellenadas con dos selladores endodónticos diferentes (Endofill y AH Plus). En la mitad de la muestra, reservada para cada sellador respectivo, se limpió el exceso de material de relleno. En la otra mitad, las áreas debilitadas no se limpiaron y el exceso de sellador se esparció sobre la dentina intrarradicular. Las áreas desgastadas intencionalmente dentro de cada raíz se restauraron con una resina compuesta fotopolimerizable microhíbrida (Z100) para reforzarlas, con y sin grabado ácido. Los postes metálicos prefabricados se fijaron con un cemento de resina dual (RelyX ARC) y los especímenes se sometieron a una prueba de extracción. El análisis estadístico se realizó mediante Shapiro-Wilk, análisis de varianza (ANOVA de una vía) y pruebas de Tukey-Kramer (p<0,05). Resultados: Los grupos rellenos con Endofill (GI, GII, GIII, GIV) presentaron los valores más bajos de fuerza de unión, los cuales fueron similares entre sí (p>0,05). Los mayores valores de fuerza de unión se observaron en raíces rellenas con AH Plus (GV, GVI, GVII, GVIII), principalmente sin limpieza de las áreas debilitadas, seguido de grabado ácido (GVII), y también con limpieza de las áreas debilitadas aunque sin grabado ácido (GVI) (p<0.05). Conclusión: Los mayores valores de fuerza de unión se observaron en las raíces rellenas con AH Plus; (1) sin limpieza de las áreas debilitadas y con grabado ácido, y; (2) con limpieza de las áreas debilitadas, pero sin grabado ácido.

Effect of dental tissue thickness on the measurement of oxygen saturation by two different pulse oximeters

Abstract This study aimed to evaluate the influence of different dental tissue thickness on the measurement of oxygen saturation (SpO2) levels in high (HP) and low (LP) blood perfusion by comparing the values obtained from two different pulse oximeters (POs) - BCI and Sense 10. Thirty freshly extracted human teeth had their crowns interposed between the POs and an optical simulator, which emulated the SpO2 and heart beats per minute (bpm) at HP (100% SpO2/75 bpm) and LP (86% SpO2/75 bpm) modes. Afterwards, the palatine/lingual surfaces of the dental crowns were worn with diamond drills. The reading of SpO2 was performed again using the POs alternately through the buccal surface of each dental crown. Data were analyzed by the Wilcoxon, Mann-Whitney and Kendall Tau-b tests (α=5%). The results showed significant difference at the HP and LP modes in the SpO2 readouts through the different dental thicknesses with the use of BCI, and at the LP mode with the use of Sense 10, which had a significant linear correlation (p<0.0001) and lower SpO2 readout values in relation to the increase of the dental thickness. Irrespective of tooth thickness, Sense 10 had significantly higher readout values (p<0.0001) than BCI at both perfusion modes. The interposition of different thicknesses of enamel and dentin influenced the POs measurement of SpO2, specially at the low perfusion mode. The POs were more accurate in SpO2 measurement when simulated perfusion levels were higher.

Resumo Este estudo avaliou a influência de diferentes espessuras de esmalte e dentina na medição dos níveis de saturação de oxigênio (SpO2) em alta (HP) e baixa (LP) perfusão sanguínea, comparando os valores obtidos em dois oxímetros de pulso (OPs) diferentes, BCI e Sense 10. Trinta dentes recém-extraídos de humanos tiveram suas coroas interpostas entre os OPs e um simulador óptico, que simulava a SpO2 e os batimentos cardíacos por minuto (bpm) nos modos de HP (100% SpO2 / 75 bpm) e LP (86% SpO2 / 75 bpm). Após, as superfícies palatinas / linguais dos dentes foram desgastadas com brocas de diamantadas. A leitura da SpO2 foi realizada novamente usando os dois OPs alternadamente através da face vestibular de cada coroa dental. Os dados foram analisados ​​pelos testes Wilcoxon, Mann-Whitney e Kendall Tau-b (α = 5%). Os resultados mostraram diferença significativa nos modos HP e LP nas leituras de SpO2 através das diferentes espessuras dentárias com o uso do BCI, e no modo LP com o uso do Sense 10, que teve correlação linear significativa (p <0,0001) e menores valores de leitura de SpO2 em relação ao aumento da espessura dentária. Independentemente da espessura do dente, o Sense 10 apresentou valores de leitura significativamente maiores (p <0,0001) do que o BCI em ambos os modos de perfusão. A interposição de diferentes espessuras de esmalte e dentina influenciaram a mensuração da SpO2 pelos OPs, especialmente no modo de baixa perfusão. Os POs foram mais precisos na mensuração da SpO2 quando os níveis simulados de perfusão foram maiores.

Do alternative scaffolds used in regenerative endodontics promote better root development than that achieved with blood clots?

Abstract The aim of this integrative review was to identify whether alternative scaffolds used in regenerative endodontics contribute to better root development, in relation to the increase in root length and thickness of dentin walls, compared with blood clot (BC) scaffolds. The literature search was conducted in PubMed, SciELO and Lilacs databases, using descriptors related to the topic. After applying the eligibility criteria, 11 articles were selected and analyzed according to the proposed aim. Five clinical and six in vivo studies, conducted in animals, compared different types of alternative scaffolds with BCs, with emphasis on platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). All scaffolds, alternative or BC, promoted an increase in root length and dentin wall thickness, with varying percentages of increase between studies. In general, there was a significant increase in root length and dentin thickness promoted by PRF and PRP scaffolds, compared with BC. It was concluded that the majority of the scaffolds tested contributed to the increase in root length and thickness of dentin walls, with emphasis on PRF and PRP.

Resumo O objetivo desta revisão integrativa foi identificar se os scaffolds alternativos utilizados em endodontia regenerativa contribuem para um melhor desenvolvimento radicular, em relação ao aumento do comprimento e espessura das paredes da dentina, em comparação com os scaffolds de coágulo sanguíneo (BC). A pesquisa bibliográfica foi realizada nas bases de dados PubMed, SciELO e Lilacs, utilizando descritores relacionados ao tema. Após a aplicação dos critérios de elegibilidade, 11 artigos foram selecionados e analisados de acordo com o objetivo proposto. Cinco estudos clínicos e seis in vivo, realizados em animais, compararam diferentes tipos de scaffolds alternativos com BCs, com ênfase no plasma rico em plaquetas (PRP) e fibrina rica em plaquetas (PRF). Todos os scaffolds, alternativos ou BC, promoveram um aumento no comprimento da raiz e na espessura da parede dentinária, com percentuais variáveis de aumento entre os estudos. Em geral, houve um aumento significativo do comprimento da raiz e da espessura da dentina promovido pelos scaffolds PRF e PRP, em comparação com a BC. Concluiu-se que a maioria dos scaffolds testados contribuiu para o aumento do comprimento das raízes e da espessura das paredes dentinárias, com ênfase em PRF e PRP.

Shaping Ability of Reciprocating and Rotary Systems After Root Canal Retreatment: a CBCT Study

Abstract The purpose of this in vitro study was to evaluate the shaping ability of reciprocating and continuous rotary systems after root canal retreatment. After preparation and root canal filling, mesial canals of 54 mandibular molars were distributed into 3 groups (n=18), according to the filling material removal and re-instrumentation protocols: WOG group - WaveOne Gold system; PTN group - ProTaper Next system; and PTU group - ProTaper Universal system. Cone-beam computed tomographic (CBCT) images acquisition of the mesial root canals was performed at different moments: (1) before instrumentation (unprepared root canals), (2) after preparation and filling, (3) after filling material removal and (4) re-instrumentation. The apical transportation (AT), centering ability (CA) and change in root canal diameter were assessed by CBCT analysis. The remaining filling material quantification was performed by radiographic examination. The statistical analyses were performed using the 3-way ANOVA, Tukey-Kramer, Kruskal-Wallis and Dunn multiple Comparison tests (p<0.05). The tested instruments did not show full CA (=1.0). PTN group had greater AT at the 5th mm in comparison with the WOG group (p<0.05). After re-instrumentation, WOG group had greater root canal diameter change at the 1st and 5th mm than PTN and PTU groups (p<0.05). There was no significant difference among groups when comparing the amount of remaining filling material after re-instrumentation (p>0.05). The tested systems provided minimal alteration in root canal morphology at the apical portion after root canal retreatment. However, WOG promoted greater change in root canal diameter.

Resumo O objetivo deste estudo in vitro foi avaliar a capacidade de modelagem de sistemas rotatórios e reciprocantes após o retratamento do canal radicular. Após o preparo e obturação do canal radicular, os canais mesiais de 54 molares inferiores foram distribuídos em 3 grupos, de acordo com os protocolos de remoção do material obturador e re-instrumentação: (n=18): grupo WOG - sistema WaveOne Gold; Grupo PTN - sistema ProTaper Next; e grupo PTU - sistema ProTaper Universal. A análise das imagens de tomografia computadorizada de feixe cônico foi realizada em diferentes momentos: (1) antes da instrumentação (canais radiculares não preparados), (2) após o preparo e obturação, (3) após a remoção do material obturador e (4) re-instrumentação. O transporte apical (TA), a capacidade de centralização (CC) e a mudança no diâmetro do canal radicular foram avaliados por análise tomográfica. A quantificação do restante do material obturador foi realizada por exame radiográfico. As análises estatísticas foram realizadas utilizando os testes de ANOVA de 3 fatores, Tukey-Kramer, Kruskal-Wallis e Comparações Múltiplas de Dunn (p<0,05). Os instrumentos não apresentaram CC perfeita (=1,0). PTN apresentou maior TA no 5º mm em comparação ao grupo WOG (p<0,05). Após a re-instrumentação, o grupo WOG apresentou maior aumento no diâmetro do canal radicular no 1° e 5° mm do que os grupos PTN e PTU. Não houve diferença significativa entre os grupos em relação à remoção do material obturador (p>0,05). Os sistemas testados proporcionaram alteração mínima na morfologia do canal radicular na porção apical após o retratamento do canal radicular. No entanto, WOG promoveu maior alteração no diâmetro do canal radicular.

Guided Endodontics in Root Canals with Complex Access: Two Case Reports

Abstract This article reported two clinical cases in which the guided endodontics was used to perform the access to the root canals. The first case presents a 40-year-old female with a history of pain related to the left maxillary canine. After radiographic examination, the presence of severe calcification up to the apical third of the root canal, associated with a periapical radiolucency, was noted. In the second case, an 85-year-old male was referred to our service with pain upon palpation, at the right mandibular first molar. The radiographic images revealed the presence of endodontic treatment and a fiberglass post in the distal root canal, which was associated with extrusion of the filling material and a periapical lesion. The 3D-guides were planned based on cone beam computed tomography and intraoral digital scanning, which were aligned using a specific software. Therefore, implant drills could be guided up to the root canal length required for each case. In the first case, a surgical root canal was created and the patient was free of signs and symptoms after the treatment was completed. In the second case, it was observed that the fiber post was worn by the drill, allowing free access to the filling material. It was possible to perform the endodontic reintervention in a more predictable way and in less time. In both cases, the use of the guided endodontics allowed the preservation of a large part of the dental structure. The procedures were performed faster, without the occurrence of fractures and perforations.

Resumo Este artigo relatou dois casos clínicos em que a endodontia guiada foi utilizada para realizar o acesso aos canais radiculares. O primeiro caso apresenta uma mulher de 40 anos com história de dor relacionada ao canino superior esquerdo. Após exame radiográfico, notou-se a presença de calcificação acentuada até o terço apical do canal radicular, associada a radioluscência periapical. No segundo caso, um homem de 85 anos foi encaminhado ao nosso serviço com dor à palpação no primeiro molar inferior direito. As imagens radiográficas revelaram a presença de tratamento endodôntico e pino de fibra de vidro no canal radicular distal, que estava associado à extrusão do material obturador e lesão periapical. Os guias-3D foram planejados com base em tomografia computadorizada de feixe cônico e escaneamento intraoral digital, os quais foram alinhados por meio de um software específico. Desta forma, brocas de implante puderam ser guiadas até o comprimento necessário do canal radicular para cada caso. No primeiro caso, foi confeccionado um canal radicular cirúrgico e o paciente ficou sem sinais e sintomas após o término do tratamento. No segundo caso, observou-se que o pino de fibra foi desgastado pela broca, permitindo o livre acesso ao material obturador. Foi possível realizar a reintervenção endodôntica de forma mais previsível e em menos tempo. Em ambos os casos, o uso da endodôntica guiada permitiu a preservação de grande parte da estrutura dentária. Os procedimentos foram realizados com maior agilidade, sem a ocorrência de fraturas e perfurações.

Fracture resistance of simulated immature teeth reinforced with different mineral aggregate-based materials

Abstract This study assessed the fracture resistance of simulated immature teeth reinforced with calcium aluminate cement (CAC) or mineral trioxide aggregate (MTA) containing calcium carbonate nanoparticles (nano-CaCO3). The microstructural arrangement of the cements and their chemical constitution were also evaluated. Forty-eight canines simulating immature teeth were distributed into 6 groups (n=8): Negative control - no apical plug or root canal filling; CAC - apical plug with CAC; CAC/nano-CaCO3 - apical plug with CAC+5% nano-CaCO3; MTA - apical plug with MTA; MTA/nano-CaCO3 - apical plug with MTA+5% nano-CaCO3; and Positive control - root canal filling with MTA. The fracture resistance was evaluated in a universal testing machine. Samples of the cements were analyzed under Scanning Electron Microscope (SEM) to determine their microstructural arrangement. Chemical analysis of the cements was performed by Energy Dispersive X-ray Spectroscopy (EDS). The fracture resistance of CAC/nano-CaCO3 was significantly higher than the negative control (p<0.05). There was no significant difference among the other groups (p>0.05). Both cements had a more regular microstructure with the addition of nano-CaCO3. MTA samples had more calcium available in soluble forms than CAC. The addition of nano-CaCO3 to CAC increased the fracture resistance of teeth in comparison with the non-reinforced teeth. The microstructure of both cements containing nano-CaCO3 was similar, with a more homogeneous distribution of lamellar- and prismatic-shaped crystals. MTA had more calcium available in soluble forms than CAC.

Resumo Este estudo avaliou a resistência à fratura de dentes imaturos simulados reforçados com cimento de aluminato de cálcio (CAC) ou trióxido agregado mineral (MTA) contendo nanopartículas de carbonato de cálcio (nano-CaCO3). O arranjo microestrutural dos cimentos e sua constituição química também foram avaliados. Quarenta e oito caninos simulando dentes imaturos foram distribuídos em 6 grupos (n=8): Controle negativo - sem plug apical ou obturação do canal radicular; CAC - plug apical com CAC; CAC/nano-CaCO3 - plug apical com CAC + 5% nano-CaCO3; MTA - plug apical com MTA; MTA/nano-CaCO3 - plug apical com MTA + 5% nano-CaCO3; e Controle positivo - obturação dos canais radiculares com MTA. A resistência à fratura foi avaliada em máquina universal de ensaios. Amostras dos cimentos foram analisadas em Microscópio Eletrônico de Varredura (MEV) para determinar seu arranjo microestrutural. A análise química dos cimentos foi realizada por Espectroscopia de Energia Dispersiva de Raio-X (EDS). A resistência à fratura de CAC/nano-CaCO3 foi significativamente maior do que o controle negativo (p<0,05). Não houve diferença significativa entre os outros grupos (p>0,05). Ambos os cimentos apresentaram microestrutura mais regular com a adição de nano-CaCO3. As amostras de MTA apresentaram mais cálcio disponível em formas solúveis do que CAC. A adição de nano-CaCO3 ao CAC aumentou a resistência à fratura dos dentes em comparação aos dentes não reforçados. A microestrutura de ambos os cimentos contendo nano-CaCO3 foi semelhante, com uma distribuição mais homogênea de cristais de formato lamelar e prismático. MTA apresentou mais cálcio disponível nas formas solúveis do que CAC.

Instrumentação foraminal: repercussões locais e sistêmicas / Foraminal enlargement: Local and systemic repercussions

Introdução: A infecção endodôntica pode alcançar a saída foraminal e, inclusive, ir além dela. Logo, a determinação da constrição apical como o limite ideal para instrumentação e obturação tem sido questionada. A instrumentação foraminal intencional é realizada com o intuito de diminuir o contingente microbiano a níveis mais favoráveis ao reparo. Entretanto, repercussões locais e sistêmicas estão associadas à sua execução. Objetivo: Realizar uma revisão crítica da literatura sobre repercussões locais e sistêmicas relativas à instrumentação foraminal intencional. Métodos: Em março de 2018, uma busca eletrônica realizada na base de dados PUBMED utilizando os termos "foraminal enlargement" OR "foraminal widening" OR "apical limit" AND "endodontics" identificou 74 artigos científicos. Esses artigos, a análise de suas referências bibliográficas e a utilização de mais 5 artigos base resultaram nos 111 estudos consultados para a realização dessa pesquisa. Resultados: A ampliação foraminal intencional nem sempre pode ser praticada em virtude de razões anatômicas e morfológicas. Quanto maior a ampliação do forame apical, maior a possibilidade de extravasamento de substâncias e/ou materiais utilizados para a realização do tratamento endodôntico. A instrumentação foraminal intencional parece ser contraindicada em pacientes que fazem ou fizeram uso de bisfosfonatos recentemente, com distúrbios de coagulação e/ou sob uso crônico de anticoagulantes e com alto risco de bacteremia. Conclusões: Os impactos da instrumentação foraminal intencional sobre o sucesso do tratamento endodôntico devem ser investigados. Contudo, os delineamentos metodológicos dos estudos clínicos devem ser cuidadosos, principalmente no tocante às condições sistêmicas dos pacientes que farão parte do universo amostral (AU).

Introduction: endodontic infection can reach and even go beyond the apical foramen. Therefore, determining apical constriction as the ideal limit for instrumentation and obturation has been questioned. Intentional foraminal enlargement is performed for the purpose of reducing the microbial contingent to levels more favorable to repair. However, local and systemic repercussions have been associated with this approach. Objectives: to critically review the literature on local and systemic repercussions relative to intentional foraminal enlargement. Methods: in March 2018, an electronic search performed on the PUBMED database using the terms "foraminal enlargement" OR "foraminal widening" OR "apical limit" AND "endodontics" identified 74 scientific articles. These articles, analysis of their references and use of another 5 base articles resulted in the 115 studies used for performing this research. Results: intentional foraminal enlargement cannot always be performed due to the anatomical and morphological conditions. The greater the apical foramen enlargement, the greater the possibility of extrusion of substances and/or materials used to perform endodontic treatment. Intentional foraminal enlargement seems to be contraindicated in patients who are taking or have recently used bisphosphonates, those with coagulation disorders and/ or under chronic use of anticoagulants and at high risk for bacteremia. Conclusions: the impacts of intentional foraminal enlargement on the success of endodontic treatment should be investigated. However, the methodological procedures of clinical studies should be carefully designed, especially taking into consideration the systemic conditions of patients who will be part of the sample (AU).

Inferior alveolar nerve paraesthesia after overfilling into the mandibular canal, confirmed by cone-beam computed tomography: a case report / Parestesia do nervo alveolar inferior após extravasamento de material obturador para o canal mandibular, confirmado por meio da tomografia computadorizada de feixe cônico: relato de caso

The filling material should be restricted to the root canal, and not extend to the periradicular tissues. Overextension occurs when there is an overflow of gutta-percha and sealer, whereas overfilling refers to the overflow only of sealer beyond the apical foramen. Both may cause several negative clinical consequences. Nevertheless, an accurate diagnosis of where they occurred cannot always be performed by conventional radiographic examination, because of the two-dimensional aspect of the image. This paper describes a clinical case of labiomandibular paraesthesia after overfilling into the mandibular canal (MC), as diagnosed by cone-beam computed tomography (CBCT), later used to perform the treatment planning. A 34-year-old Caucasian female patient sought a private dental clinic complaining of pain in the right mandibular posterior region. After taking the anamnesis and performing clinical and radiographic exams, the patient was diagnosed with pulp necrosis in the second right mandibular molar, and underwent root canal treatment. The final radiography showed overextension or overfilling, probably into the MC. About 2 hours after the procedure, the patient reported paraesthesia of her lower right lip and chin. A CBCT confirmed a small overfilling into the MC. For this reason, vitamin B12 was prescribed as the first treatment option. After 7 days, the patient reported a significant decrease in paraesthesia, and was completely normal after 15 days. This case report shows that CBCT is an effective radiographic diagnostic tool that can be used as an alternative in clinical cases of labiomandibular paraesthesia caused by overextension or overfilling (AU)

O material obturador deve preencher todo o canal sem extravasar para os tecidos perirradiculares. O extravasamento de guta-percha e cimento além do forame apical, denomina-se sobrextensão, enquanto o termo sobreobturação refere-se ao extravasamento de cimento endodôntico. Ambos podem causar consequências clínicas negativas, porém um preciso diagnóstico nem sempre é logrado somente a partir do exame radiográfico convencional em razão de sua natureza bidimensional. O presente relato descreve um caso clínico de parestesia de lábio inferior e mento após o extravasamento de cimento obturador para o canal mandibular (CM), diagnosticado por meio da tomografia computadorizada de feixe cônico (TCFC), também utilizada para o planejamento do tratamento. Paciente do gênero feminino, 34 anos, leucoderma, procurou atendimento odontológico particular queixando-se de dor odontogênica na região posterior direita da mandíbula. Finalizados a anamnese e o exame clínico-radiográfico, diagnosticou-se a necrose pulpar do segundo molar inferior direito, ulteriormente submetido ao tratamento endodôntico. A radiografia final evidenciou provável extravasamento de material obturador para o interior do CM. Aproximadamente 2 horas após, a paciente relatou parestesia no lábio inferior direito e no queixo, e a TCFC confirmou a presença de pequena quantidade de cimento obturador no CM. Por conseguinte, a prescrição de vitamina B12 foi o tratamento de escolha. Decorridos 7 dias, a paciente referiu significativa diminuição da parestesia e após 15 dias os padrões de normalidade estavam completamente restabelecidos. O presente relato de caso demonstra que a TCFC é uma ferramenta de diagnóstico potencialmente empregada em casos de parestesia labiomandibular causada por sobrextensão ou sobreobturação (AU)

Accuracy of cone-beam computed tomography in measuring the thickness of radicular dentin

Abstract The purpose of this study was to evaluate the accuracy of Cone-Beam Computed Tomography (CBCT) in measuring radicular dentin thickness focused on intraradicular post placement planning treatment. Ten single-rooted human premolars were selected. The teeth were divided into three segments (cervical, middle and apical). The coronal face of the apical and middle sections was selected for the dentin thickness assessment; which was measured from the external root surface to the root canal wall, on the buccal, lingual, mesial, and distal surfaces of each tooth. In situ anatomical measurement was the reference standard, and the corresponding axial CBCT imaging were evaluated by the i-CAT software. The one-way ANOVA test and the Bonferroni post hoc test were applied to compare the groups (p>0.05). CBCT imaging measurements (p=0.003) overestimated the radicular dentin thickness compared to the reference standard. Descriptive analysis showed that the greatest difference between the reference standard and the tomographic measurement means were 0.20 mm. One-way ANOVA test found the statistical significant difference among group's measurements. Bonferroni correction demonstrated statistically significant difference only related lingual surface for the CBCT imaging measurements. CBCT imaging measurements overestimated the radicular dentin thickness. However, the measurement difference was clinically acceptable.

Resumo O objetivo deste estudo foi avaliar a precisão da Tomografia Computadorizada de Feixe Cônico (TCFC) na mensuração da espessura da dentina radicular no planejamento de tratamento envolvendo a cimentação de pinos intrarradiculares. Dez pré-molares humanos unirradiculares foram selecionados. Os dentes foram divididos em três segmentos (cervical, médio e apical). A face coronal dos terços apical e médio foi selecionada para a avaliação da espessura da dentina; que foi medida a partir da superfície externa da raiz até a parede do canal radicular, nas superfícies vestibular, lingual, mesial e distal de cada dente. A medida anatômica in situ foi o padrão de referência, e a imagem de TCFC axial correspondente foi avaliada pelo software i-CAT. O teste de 1-fator ANOVA e o teste post hoc de Bonferroni foram aplicados para comparar os grupos (p>0,05). As medidas de imagem da TCFC (p=0,003) superestimaram a espessura da dentina radicular em comparação a referência padrão. A análise descritiva mostrou que a maior diferença entre a referência padrão e a medida tomográfica foi de 0,20 mm. O teste ANOVA encontrou a diferença de significância estatística entre as medidas do grupo. A correção de Bonferroni demonstrou diferença estatisticamente significante apenas relacionada às medidas de imagem da TCFC. A medida de imagem da TCFC superestimou a espessura da dentina radicular. No entanto, a diferença de medição foi clinicamente aceitável.

Endodontic Surgery Associated with Guided Tissue Regeneration Technique: Case Report / Cirurgia Parendodôntica Associada à Técnica de Regeneração Tecidual Guiada: Relato de Caso

Non-surgical endodontic retreatment should always be the first option for reintervention when the initial endodontic treatment fails. The surgical treatment, called periradicular surgery, will be the procedure of choice when there is no success after the conventional endodontic retreatment. The purpose of this article is to describe clinical case of endodontic surgery, associated with guided tissue regeneration (GTR). A male patient, 24 years old, was referred for endodontic surgery on tooth 12 after two unsuccessful endodontic interventions. During the surgery, osteotomy, lesion curettage, apicectomy, retrograde obturation with Mineral Trioxide Aggregate (MTA), and filling of the bone failure with lyophilized bone and reabsorbable collagen membrane were performed. After six months of follow-up, the patient did not present any type of painful symptomatology. The endodontic surgery, associated with a technique of guided tissue regeneration, was efficient to solve this clinical case. (AU)

O retratamento endodôntico não cirúrgico deve sempre ser a primeira opção de reintervenção quando o tratamento endodôntico inicial falha. Já o tratamento cirúrgico, ou cirurgia parendodôntica, será o procedimento de escolha quando não há sucesso após o retratamento endodôntico convencional. O objetivo deste artigo é descrever um caso clínico de cirurgia parendodôntica, associada à regeneração tecidual guiada (RTG). O paciente, gênero masculino, 24 anos, foi encaminhado para cirurgia parendodôntica no dente 12 após duas intervenções endodônticas sem sucesso. Durante a cirurgia foram realizadas manobras de osteotomia, curetagem da lesão, apicectomia, obturação retrógrada com Mineral Trióxido Agregado (MTA), além de preenchimento da falha óssea com osso liofilizado e membrana de colágeno reabsorvível. Após seis meses de acompanhamento do caso, o paciente não apresentou nenhum tipo de sintomatologia dolorosa. A cirurgia parendodôntica, associada à técnica de regeneração tecidual guiada, foi eficiente para solucionar este caso clínico. (AU).

Residual smear layer after root canal instrumentation by using Niti, M-Wire and CM-Wire instruments: A scanning electron microscopy analysis.

OBJECTIVE: The purpose of this study was to compare the amount of residual smear layer after root canal instrumentation by using Ni-Ti, M-Wire, and CM-Wire instruments. MATERIALS AND METHODS: Seventy-two mandibular incisors were randomly divided into six groups according to the system used: WaveOne (WO), Reciproc (RP), Unicone (UC), ProTaper Next (PN), Mtwo (MT), and HyFlex (HF). Afterward, the specimens were cleaved in the mesiodistal and buccolingual direction for analysis by scanning electron microscopy. RESULTS: Considering both directions and root canal thirds, there was no difference between HF, MT, and PN. RP, UC, and WO presented a significant difference between the directions, and the cervical third showed a significantly smaller quantity of residual smear layer compared with the apical third. When the systems were compared among them, there was a significant difference only between RP and WO. CONCLUSIONS: Residual smear layer observed after instrumentation with the different systems was similar, except for quantities between the reciprocating systems.

Luxação extrusiva de um incisivo central Permanente jovem: relato de caso clínico / Extrusive luxation of an immature permanent central incisor: clinical case report

Objetivo: O objetivo deste artigo é apresentar o relato de um caso clínico de luxação extrusiva de dente permanente com rizogênese incompleta, onde não foi necessária a realização de intervenção endodôntica. Relato de caso: Paciente de 6 anos de idade compareceu ao serviço de urgência da Policlínica Odontológica da Universidade do Estado do Amazonas (UEA) para atendimento após queda durante atividade de lazer, apresentando traumatismo direto na boca. Foi informado durante a consulta inicial que o incidente havia ocorrido há cerca de três dias, e que o atendimento imediato logo após o trauma foi realizado em um Serviço de Pronto Atendimento, porém, nenhum tipo de procedimento na cavidade oral foi realizado. Após exames clínico e radiográfico observou-se que o dente 21 apresentava deslocamento parcial para fora do alvéolo dentário no sentido axial, com alteração da oclusão, dor local à palpação e mobilidade dentária. Foi realizada profilaxia da área afetada, e anestesia do dente luxado e tecidos adjacentes. O reposicionamento do dente foi realizado em seguida, pressionando-o e tracionando-o de forma suave e contínua até a sua correta posição dentro do alvéolo. A área afetada foi limpa com gaze estéril embebida em soro fisiológico, e foi instalada uma contenção rígida confeccionada com fio ortodôntico e resina composta. Conclusão: O reposicionamento da maneira adequada do dente traumatizado dentro do alvéolo dentário, num período de tempo hábil, seguido de sua proservação, permitiram a manutenção da vitalidade do tecido pulpar, e consequentemente, o desenvolvimento do segmento radicular.

Objective: The objective of this article is to present a clinical case of extrusive luxation of an immature permanent tooth, with no endodontic management. Case report: A 6-year-old patient was provided to emergency treatment at the State University of Amazonas, as a result of a fall, with a direct trauma to the mouth. It was informed during the initial consultation that the incidente has occurred three days after. Emergency examination had been carried out by an Emergency Service; however, any type of procedure in the oral cavity was performed in ths occasion. After clinical and radiographic examinations, it was observed that tooth 21 presented partial displacement from the alveolar socket in the axial direction, with occlusion alteration, local pain to palpation and dental mobility. Cleaning of the affected area and anesthesia of the dislocated tooth and adjacent tissues were performed. Then, tooth repositioning was performed by pressing and tracing it smoothly and continuously until its correct position within the alveolar socket. The affected area was cleaned with sterile gauze soaked in saline solution, and a rigid containment made of orthodontic wire and composite resin was installed. Conclusion: A proper repositioning of the traumatized tooth within the alveolar socket, followed by its clinical followup, allowed the pulp tissue to remain vital, and consequently, the complete development of the root portion

Evaluation of 17% EDTA and 10% citric acid in smear layer removal and tubular dentin sealer penetration.

The purpose of this study was to compare the efficacy of different chelating solutions (17% EDTA and 10% citric acid) on the smear layer removal, and their effect on tubular dentin sealer penetration. Sixty root canals were prepared and distributed into four groups (n = 15) according to the final irrigation protocol: G1, final irrigation with 2.5 mL of distilled water; G2, final irrigation with 2.5 mL of 2.5% sodium hypochlorite solution; G3, final irrigation with 2.5 mL of 17% EDTA; and G4, final irrigation with 2.5 mL of 10% citric acid. Five specimens from each group were not filled to assess smear layer removal by scanning electron microscopy. Ten specimens from each group were filled for analysis of sealer penetration into dentinal tubules by confocal laser scanning microscopy. Smear layer removal (Kruskal-Wallis and Dunn's tests) and sealer penetration (F and Tukey's tests) were statistically analyzed with 95% of significance level. G3 and G4 had greater smear layer removal rates in the cervical and middle thirds, in comparison with G1 and G2 (p < .05). G3 and G4 had the highest percentages of sealer penetration in all thirds, in comparison with G1 and G2 (p < .05). Smear layer removal was effective only at the cervical and middle thirds when the chelating solutions were used. Sealer penetration into the dentinal tubules significantly increased in all root thirds when the specimens were treated with both chelating solutions.