Comparative effects of final canal irrigation with chitosan and EDTA

Chitosan is a natural, biocompatible chelating substance with potential for dental use. This study compared the effects of final canal irrigation with chitosan and EDTA on dentin microhardness, sealer dentin tubules penetration capacity, and push-out strength. Methodology: Fifty canine roots were distributed according to the final irrigation protocol (n=10): G1- 15% EDTA with conventional irrigation; G2- 15% EDTA with Endovac; G3- 0.2% chitosan with conventional irrigation; G4- 0.2% chitosan with Endovac; and G5- without irrigation. Specimens were obturated (AH Plus) and sectioned in 3 slices per root third. The first slice was used for microhardness and sealer penetration assessments under a laser confocal microscope. The second was utilized in a push-out strength test. The third slice was discarded. Data were analyzed using 2-way ANOVA and Tukey's post hoc test (α<0.05). Failure mode was determined at x40 magnification. Results: Microhardness reduction was more significant in groups G2 and G4 (p<0.05). Sealer penetration through dentin was significantly greater in group G2 (p<0.05). There was no significant difference between groups G1, G3, and G4 (p>0.05). In general, all experimental groups presented similar bond resistance (p>0.05) that significantly differed from the control (p<0.001). Mixed type failures were predominant. Conclusions: In general, 0.2% chitosan and 15% EDTA solutions act in a similar manner with regard to the variables studied. The use of Endovac potentiates the effect of these solutions

Effect of sonic and ultrasonic activation on physicochemical properties of root canal sealers

Objective: To evaluate the effect of ultrasonic and sonic activation on physicochemical properties of AH Plus, MTA Fillapex, ADSeal, GuttaFlow Bioseal, and GuttaFlow 2 sealers. Methodology: Three experimental groups were formed: no activation (NA), ultrasonic activation (UA), and sonic activation (SA). The sealers were manipulated according to the manufacturers’ instructions. A 3-mL syringe was adapted to receive 1 mL of sealer. Activation was performed with a 20/.01 ultrasonic insert (20 s/1W) in the UA group. A size 35.04 sonic tip was used (20 s/10,000 cycles/min-1) in the SA group. The molds for physicochemical analysis were filled and evaluated according to ANSI/ADA specification no. 57: setting time (ST), flow (FL), dimensional change (DC), solubility (SB), and radiopacity (RD). Statistical analysis was performed by Kruskal-Wallis, one-way ANOVA, and Tukey's tests (P<0.05). Results: Regarding ST, only AH Plus and GuttaFlow 2 in the NA group met the ANSI/ADA standards. All FL values were greater than 20 mm in diameter, as determined by ANSI/ADA. The tested sealers and protocols did not comply with the ANSI/ADA standards for DC. As for SB, only MTA Fillapex, regardless of the activation protocol, did not follow the ANSI/ADA standards. All of the investigated sealers, regardless of the activation protocol, presented radiographic density higher than 3 mm Al, as proposed by ANSI/ADA. Conclusions: UA and SA promoted changes in the physicochemical properties of the evaluated root canal sealers, mainly in ST and F. Thus, it is important to evaluate the physicochemical properties of endodontic sealers associated with activation techniques prior to clinical application in order to determine whether the properties follow the parameters set by ANSI/ADA, ensuring safety and quality of root canal filling

Micro-computed tomographic assessment of the variability and morphological features of root canal system and their ramifications

Objectives: This study assessed the incidence and variability features of root canals system (RCS) and their ramifications according to Pucci & Reig (PR) (1944) and the American Association of Endodontists (AAE) (2017) by micro-computed tomography (μCT). Methodology: 500 representative extracted human teeth of each tooth group (n=50) (maxillary/mandibular central and lateral incisors, canines, first and second premolars and molars) were scanned by μCT with a resolution of 26.70 μm. The reconstructed cross-sections images and the visualization of the continuous slices in the transversal axis were performed using DataViewer software. RCS were classified according to Pucci & Reig (main canal, collateral canal, lateral canal, secondary canal, accessory canal, intercanal, recurrent canal) and AAE (main canal, accessory canal, lateral canal). The apical deltas were assessed for both classifications. The prevalence of apical deltas was evaluated using the Chi-squared test (p<0.05). Results: According to PR, a higher incidence of lateral canals was observed in maxillary canines (10%), central incisors (8%) and first premolars (6%). Using AAE, the highest incidence of lateral canals was observed in the mandibular first premolars (85%), first and second molars (84%), lateral incisors (67%), canines (59%), and in maxillary first premolars (52%). Regarding accessory canals, the PR showed a frequency in 2% of the maxillary lateral incisors and maxillary and mandibular first premolars and 3% of mandibular first and second molars. On the other hand, the AAE showed the highest incidence of accessory canals in 86% of the maxillary first premolars, 71% in mandibular lateral incisors, 69% in mandibular first premolars, 65% in mandibular canines, and 56% in maxillary canines. The PR showed the lowest incidence of apical deltas for all dental groups when compared with AAE (p=0.004). Interestingly, distal canals in maxillary molars showed a significant discrepancy between classifications (p=0.027). Conclusions: μCT enabled accurately describing the RC system and related ramifications, adding to the PR and AAE classifications, with some discrepancies reported for maxillary molars. Clinical Relevance This μCT study enabled a thorough description of the variability among root canals and their ramifications, including clinically relevant details on the presence and location of lateral canals and accessories in all human tooth groups, beyond the currently existing classification systems

Analysis of the internal anatomy of mandibular molars using different cone-beam computed tomography protocols

The aim of this study was to analyze the root canal anatomy variations of permanent mandibular molars using three different cone-beam computed tomography (CBCT) protocols. Material and methods: Thirty-five freshly extracted first and second mandibular molars were collected and subjected to three CBCT protocols: i-CAT Classic (ICC); i-CAT Next Generation (ICN), and PreXion 3D (PXD). Images were evaluated by two previously calibrated and experienced endodontists. The morphological root canal configurations were classified according to Vertucci. Data were analyzed for frequency, and the binomial and Kappa tests were then performed (α = 0.05). Results: ICC and ICN were able to diagnose a higher percentage of anatomical variations in the mesial roots. In this same root, Vertucci’s type V was the most prevalent, and in distal was the type I. In comparisons of CBCT techniques for agreement, significant differences in the mesial root canals were found in the following: ICC versus (vs) ICN; ICC vs PXD; and ICN vs PXD (p 0.05). The level of agreement in mesial roots was poor or absent, while in distal was moderate. Conclusion: Anatomical variations were found in both root canals, with higher variability in the mesial, highlighting ICC and ICN protocols, and the prevalence of Vertucci’s type V, while in the distal prevailed the type I

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.

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

Influence of bioceramic intracanal medication on the bond strength of bioceramic root canal sealer

Abstract To investigate the influence of the remaining volume of a new intracanal medication based on bioceramic compounds on the bond strength (BS) and formation of an adhesive interface between calcium silicate-based and epoxy resin-based root canal sealers. For this purpose, the specimens were distributed according to the intracanal medication (n = 26): Bio-C Temp (BCT) and Ultracal XS (UXS). The roots were scanned in microCT, and after 7 days, the medication was removed. Then a new scan was performed to evaluate the volume of medication remaining. Subsequently, 40 specimens were redistributed into 2 subgroups (n = 10) and filled according to the sealer used: AH Plus (AHP) and Bio-C Sealer (BCS), to assess the bond strength by using the push-out test, and the adhesive interface by confocal laser fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The t test showed a smaller remainder of BCT (1.77 ± 0.86) compared with UXS (10.47 ± 5.78), irrespective of the root third evaluated. The BS showed that teeth with BCT + BCS had higher bond strength values (3.70 ± 1.22) when compared to the other groups: BCT + AHP (2.15 ± 1.07), UXS + BCS (3.18 ± 1.09) and UXS + AHP (2.11 ± 1.02) (p<0.001). The cervical third had higher BS when compared with the middle and apical thirds (p < 0.001), and higher number of adhesive failures. The adhesive interface in SEM and CLSM images showed better adaptation for the association between BCT + BCS. Intracanal medication and silicate-based endodontic sealer appeared to interact chemically by forming a biomineralizing layer, allowing for an increase in the bond strength and forming an adhesive interface between the materials, with no or less gap formation

Evaluation of the expression of image artifacts created by high-density materials in cone beam computed tomography, micro and nanocomputed tomographies

Este estudo propôs avaliar a expressão dos artefatos de imagens causados pelo fenômeno de endurecimento dos feixes de raios X (Beam hardening) nas imagens obtidas por tomografia computadorizada de feixe cônico, micro e nanotomografia computadorizadas com diferentes protocolos de escaneamento e reconstrução. Molares inferiores (n=12), foram escaneados por nanoCT, microCT e por 4 diferentes aparelhos de TCFC em protocolos de alta (HR) e baixa (NR) resolução: (1) 3D Accuitomo 170 (ACC), (2) NewTom VGi evo (New), ProMax 3D Max (Pro) e Pax-i3D Green Premium (Pax), após a obturação do sistema de canais radiculares (SCR). Para a padronização e registro das imagens obtidas com os diferentes aparelhos, utilizou-se o programa FIJI ImageJ. As imagens das reconstruções axiais, sagitais e coronais obtidas foram avaliadas qualitativamente em relação à presença de artefatos de imagem por três examinadores calibrados, por meio de atribuição dos seguintes escores, em relação aos tipos de artefatos de imagens causados pelo endurecimento dos feixes de raios X (estrias escuras, áreas hipodensas e distorção): (1) definitivamente ausente; (2) provavelmente ausente; (3) não estou certo; (4) provavelmente presente e (5) definitivamente presente, e sobre a possibilidade de uso das imagens para fins de diagnóstico em Endodontia: (0) Não e (1) Sim. Os dados qualitativos foram avaliados estatisticamente por meio do teste Fleiss Kappa e os equipamentos foram comparados uns aos outros para cada tipo de reconstrução (axial, sagital e coronal) separadamente. Correção para a hipótese simultânea foi realizada de acordo com o teste de idák, com nível de probabilidade de 95%. A concordância inter-examinador evidenciou maior concordância para os protocolos New HR, Pax HR e Pro NR em relação à presença de estrias escuras, áreas hipodensas e distorção, respectivamente. Para a concordância intra-examinador, observou-se maior concordância para os protocolos em microCT para estrias escuras e Pax HR para áreas hipodensas e distorção. Em relação à presença de estrias escuras, observou-se maior expressão deste tipo de artefatos nos protocolos Pax NR (38%), Pax HR (34,3%) e Pro HR (3,7%). A presença de áreas hipodensas foi detectada em 100% das imagens obtidas nos protocolos Pax HR e em 99,1% dos protocolos Pax NR. Quando avaliada a distorção do material obturador, o teste Kappa evidenciou a maior distorção nos protocolos Pax HR e Pro NR (100%) e Pax NR e Pro HR (99,1%). Foi possível a utilização das imagens para fins de diagnóstico em Endodontia em 100% dos volumes adquiridos nos protocolos em nanoCT, microCT, ACC HR e New NR. Os protocolos de escaneamento com voxels de tamanhos reduzidos associados a elevados valores de kVp e mA e maior número de imagens bases, para dentes obturados, propiciaram a menor formação de artefatos metálicos causados pelo fenômeno de endurecimento dos feixes de raios X, independentemente do equipamento avaliado. Ainda, os resultados do presente estudo, sugerem que diante da necessidade de diagnóstico em dentes com canais radiculares obturados, os protocolos clínicos de aquisição de imagens devem ser realizados nos equipamentos 3D Accuitomo 170 ou NewTom VGi evoThis study evaluated the expression of image artifacts caused by the X-ray beam hardening phenomenon in images obtained by cone beam computed tomography, micro and nanocomputed tomographies, using different scanning and reconstruction protocols. Mandibular molars (n = 12) were scanned by nanoCT, microCT and by 4 different CBCT machines in high (HR) and normal (NR) resolution protocols: (1) 3D Accuitomo 170 (ACC), (2) NewTom VGi evo (New), ProMax 3D Max (Pro) and Pax-i3D Green Premium (Pax), after root canal filling. FIJI ImageJ software was used for standardization and recording of the images obtained with the different devices. The images of the axial, sagittal and coronal reconstructions were evaluated qualitatively by three calibrated examiners, through assignment of the following scores regarding the types of image artifacts caused by X-ray beam-hardening (dark streaks, hypodense areas and distortion): (1) definitely absent; (2) probably absent; (3) unsure; (4) probably present; and (5) definitely present. The scores used to evaluate the possibility of using the images for diagnostic purposes in Endodontics were: (0) No and (1) Yes. Qualitative data were statistically evaluated using the Fleiss\' Kappa test and the devices were compared to each other for each type of reconstruction (axial, sagittal and coronal) separately. Correction for the simultaneous hypothesis was performed according to the idák test, with probability level of 95%. The inter-examiner agreement showed greater agreement for the New HR, Pax HR and Pro NR protocols in relation to the presence of dark streaks, hypodense areas and distortion, respectively. For intra-examiner agreement, greater agreement was found for the microCT protocols for dark streaks and Pax HR for hypodense areas and distortion. In relation to the presence of dark streaks, the Pax NR (38%), Pax HR (34.3%) and Pro HR (3.7%) protocols showed greater expression of this type of artifact. The presence of hypodense areas was detected in 100% of the images obtained in the Pax HR protocols and in 99.1% of those obtained in the Pax NR protocols. When evaluating root canal filling distortion, the Kappa test showed the highest distortion in the Pax HR and Pro NR (100%) and Pax NR and Pro HR (99.1%) protocols. It was also possible to use the images for endodontic diagnosis in 100% of the volumes acquired in the protocols in nanoCT, microCT, ACC HR and New NR. The scanning protocols with reduced sizes of voxels associated with high values of kVp and mA and increased number of two-dimensional projections, for filled teeth, results in the lowest expression of metallic artifacts caused by the X-ray beam hardening phenomenon, independently of the evaluated device. Furthermore, the results of the present study suggest that, in view of the need for diagnosis in teeth with root canal filling, the clinical protocols for image acquisition should be performed on the 3D Accuitomo 170 or NewTom VGi evo device

Micro-computed tomography analysis of the internal anatomy of maxillary anterior teeth

O estudo da anatomia interna do complexo sistema de canais radiculares (SCR) é de fundamental importância no diagnóstico, planejamento e tratamento endodôntico. O objetivo deste estudo foi avaliar a anatomia do SCR de incisivos centrais, laterais e caninos superiores, por meio de microtomografia computadorizada (&mu;TC). Foram usados 50 incisivos centrais (ICS), 50 laterais (ILS) e 50 caninos superiores (CS), escaneados no microtomógrafo SkyScan 1174. Os espécimes foram reconstruídos e analisados os parâmetros bidimensionais (número, área, circularidade, fator de forma, diâmetro maior, diâmetro menor) a 1, 2, 3, 4 e 5 mm do forame apical e tridimensionais (volume, área de superfície, SMI, número e localização de canais acessórios, localização e volume do ombro palatino), bem como as características anatômicas externas dos dentes (comprimento, dimensões da coroa, curvatura radicular, posição do forame, presença, localização, profundidade e extensão dos sulcos) e análise qualitativa da anatomia interna dos modelos tridimensionais. Os resultados bidimensionais mostraram a presença de um canal no terço apical nos três grupos dentais estudados. Os valores de circularidade e fator de forma evidenciaram forma circular dos canais no terço apical tanto para os ICS quanto para os CS, com tendência ao achatamento destes canais no terço apical nos ILS. O teste de regressão linear evidenciou aumento progressivo dos diâmetros maior e menor nos 5 milímetros avaliados (p<0,001), com aumentos respectivos de 0,09 mm e 0,07 mm para os ICS; 0,12 mm e 0,07 mm para os ILS e 0,11 mm e 0,06 mm para os CS. A análise tridimensional demonstrou que as maiores médias de volume (mm3) e área de superfície (mm²) foram encontradas nos CS. Os valores de SMI foram semelhantes para os três grupos, sugerindo forma tridimensional com tendência a um cilindro. Os modelos tridimensionais evidenciaram a presença de 100% dos dentes com a classificação do Tipo I. Em relação à análise de canais acessórios foi possível observar alto índice de canais laterais, secundários e acessórios nos ICS, ILS e CS. Observou-se maior prevalência de curvatura leve nos ICS (45%) e moderada nos ILS (50%) e CS (50%). O volume do ombro palatino foi menor nos ILS (11,46 ± 3,09) quando comparado com os ICS (14,15 ± 3,85) e CS (13,95 ± 2,55). Na análise externa, observou-se maiores valores de comprimento nos CS (26,59 ± 1,93) e maiores dimensões da coroa nos ICS (10,46 ± 1,03). A maior prevalência da posição do forame foi na região central (22%), distopalatina (30%) e mesiovestibular (28%) para ICS, ILS e CS, respectivamente. A presença de sulcos radiculares foi de 2% nos ICS e 4% nos ILS. Desta forma, conclui-se que os dados bi e tridimensionais obtidos por meio da &mu;TC permitiram observar diferentes características morfológicas da anatomia interna e externa dos dentes anteriores superiores.The study of the internal anatomy of the root canal system (RCS) is of paramount importance for the diagnosis, planning and endodontic treatment plan. The aim of this study was to evaluate the RCS anatomy of maxillary central and lateral incisors and canines by micro-computed tomography (&mu;CT). Fifty maxillary central incisors (MCI), 50 maxillary lateral incisors (MLI) and 50 maxillary canines (MC) scanned in the SkyScan 1174 &mu;CT device. The images were reconstructed for analysis of two-dimensional (number, area, roundness, form factor, major and minor diameter) at 1, 2, 3, 4 and 5 mm short of the apical foramen and three-dimensional parameters (volume, surface area, structure model index-SMI, number and localization of accessory canals, and localization and volume of palatal shoulder), as well as external anatomic characteristics of the teeth (length, crown dimensions, root curvature, foramen position, presence, position, depth and extent of radicular grooves) and for qualitative analysis of the internal anatomy of 3D models. The 2D analysis showed the presence of one canal in the apical third in the three dental groups. The roundness and form factor values revealed a circular canal in the apical third in the MCI and MC. In the MLI, these form descriptors indicated a circular form with tendency to flattening in the apical third. The linear regression test showed a progressive increase in the major and minor diameters in the 5 mm assessed (p <0.001), with respective increases of 0.09 mm and 0.07 mm for the MCI; 0.12 mm and 0.07 mm for MLI and 0.11 mm and 0.06 mm for MC. The 3D analysis revealed that the greatest means of volume (mm3) and surface area (mm2) were found in MCs. The SMI values were similar for the three dental groups, and suggested a tendency to a 3D cylinder-like geometry of the root canals. The analysis of 3D models showed that 100% of the teeth presented Vertuccis (1984) type I root canal configuration. Concerning the analysis of accessory canals was observed high rates of lateral, secondary and accessories canals in the MCI, MLI and MC. There was a prevalence of mild curvature in the MCI (45%) and moderate in the MLI (50%) and MC (50%). Palatal shoulder volume was smaller in the MLI (11,46 ± 3,09) than in the MCI (14,15 ± 3,85) and MC (13,95 ± 2,55). The external tooth analysis showed greater length values for MC (26,59 ± 1,93) and greater crown dimensions for MCI (10,46 ± 1,03). The prevalence of foramen position was the central (22%), distopalatal (30%) and mesiobuccal (28%) regions for MCI, MLI and MC, respectively. Presence of radicular grooves was observed in 2% of MCI and 4% of MLI. Thus, it may be concluded that the two and three-dimensional data obtained by &mu;CT allowed to observe different morphological characteristics of internal and external anatomy of the maxillary anterior teeth