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STATEMENT OF PROBLEM: The mechanical behavior of ceramic endocrowns is unclear. PURPOSE: The purpose of this in vitro and 3-dimensional finite element analysis (3D-FEA) study was to evaluate the mechanical behavior of endodontically treated teeth restored with ceramic endocrowns made by using different computer-aided design and computer-aided manufacturing (CAD-CAM) systems. MATERIAL AND METHODS: Sixty mandibular human molars were endodontically treated, prepared for endocrowns, and divided into 4 groups (n=15) according to the following various ceramic systems: leucite-based glass-ceramic (LC group), lithium disilicate-based glass-ceramic (LD group), glass-ceramic based on zirconia-reinforced lithium silicate (LSZ group), and monolithic zirconia (ZR group). After adhesive bonding, the specimens were subjected to thermomechanical loading and then to fracture resistance testing in a universal testing machine. The failure mode of the specimens was qualitatively evaluated. Three-dimensional FEA was performed to evaluate the stress distribution in each group. Data were analyzed by using a 1-way ANOVA and the Tukey HSD test (α=.05). RESULTS: Statistically significant differences among the groups were observed (P<.05). The outcomes of the LC, LD, and LSZ groups were similar (1178 N, 1935 N, and 1859 N) but different from those of the ZR group (6333 N). The LC and LD groups had a higher ratio of restorable failures, while LSZ and ZR had more nonrestorable failures. Fractographic analysis indicated a regular failure pattern in the ZR group and irregular failure patterns in the other groups. Three-dimensional FEA revealed similar values and stress pattern distributions among the groups. CONCLUSIONS: The mechanical performance of monolithic zirconia was better than that of the other ceramic endocrowns considered in this research; however, monolithic zirconia presented a higher rate of catastrophic tooth structure failure.
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Coroas , Falha de Restauração Dentária , Cerâmica , Desenho Assistido por Computador , Porcelana Dentária , Análise do Estresse Dentário , Humanos , Teste de MateriaisRESUMO
AIM: To assess the influence of cervical preparation on fracture susceptibility of roots. MATERIAL AND METHODS: During root canal instrumentation, the cervical portions were prepared with different taper instruments: I: no cervical preparation; II: #30/.08; III: #30/.10; IV: #70/.12. The specimens were sealed with the following filling materials (n = 8), A: unfilled; B: Endofill/gutta-percha; C: AH Plus/gutta-percha; D: Epiphany SE/Resilon. For the fracture resistance test, a universal testing machine was used at 1 mm per minute. RESULTS: anova demonstrated difference (P < 0.05) between taper instruments with a higher value for group I (205.3 ± 77.5 N) followed by II (185.2 ± 70.8 N), III (164.8 ± 48.9 N), and IV (156.7 ± 41.4 N). There was no difference (P > 0.05) between filling materials A (189.1 ± 66.3 N), B (186.3 ± 61.0 N), C (159.7 ± 69.9 N), and D (176.9 ± 55.2 N). CONCLUSIONS: Greater cervical wear using a #70/.12 file increased the root fracture susceptibility, and the tested filling materials were not able to restore resistance.
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Materiais Restauradores do Canal Radicular/química , Obturação do Canal Radicular/métodos , Preparo de Canal Radicular/instrumentação , Fraturas dos Dentes/etiologia , Raiz Dentária/lesões , Dente não Vital/complicações , Análise de Variância , Análise do Estresse Dentário , Humanos , Incisivo/cirurgia , Fraturas dos Dentes/classificação , Fraturas dos Dentes/prevenção & controleRESUMO
Purpose: This study compared the root canal anatomy between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) images before and after biomechanical preparation and root canal filling. Materials and Methods: Isthmus-containing mesial roots of mandibular molars (n=14) were scanned by micro-CT and 3 CBCT devices: 3D Accuitomo 170 (ACC), NewTom 5G (N5G) and NewTom VGi evo (NEVO). Two calibrated observers evaluated the images for 2-dimensional quantitative parameters, the presence of debris or root perforation, and filling quality in the root canal and isthmus. The kappa coefficient, analysis of variance, and the Tukey test were used for statistical analyses (α=5%). Results: Substantial intra-observer agreement (κ=0.63) was found between micro-CT and ACC, N5G, and NEVO. Debris detection was difficult using ACC (42.9%), N5G (40.0%), and NEVO (40%), with no agreement between micro-CT and ACC, N5G, and NEVO (0.05<κ<0.12). After biomechanical preparation, 2.4%-4.8% of CBCT images showed root perforation that was absent on micro-CT. The 2D parameters showed satisfactory reproducibility between micro-CT and ACC, N5G, and NEVO (intraclass correlation coefficient: 0.60-0.73). Partially filled isthmuses were observed in 2.9% of the ACC images, 8.8% of the N5G and NEVO images, and 26.5% of the micro-CT images, with no agreement between micro-CT and ACC, and poor agreement between micro-CT and N5G and NEVO. Excellent agreement was found for area, perimeter, and the major and minor diameters, while the roundness measures were satisfactory. Conclusion: CBCT images aided in isthmus detection and classification, but did not allow their classification after biomechanical preparation and root canal filling.
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This study evaluate shaping ability of heat-treated NiTi-alloy instruments associated with different final irrigation protocols in flattened root canals. Thirty human mandibular incisors with flattened root canals were divided into 5 groups (n = 10): (XP) Original Protocol XP-endo Shaper; (XP-WT) Original Protocol XP-endo Shaper with working time variation; (XP-K) XP-endo Shaper with kinematics variation; (XP-WTK) XP-endo Shaper with kinematics and working time variations; (Hyflex) Hyflex CM. For the variation in working time protocols the same sample of the XP-endo Shaper groups with and without kinematic variation were used. To evaluate final irrigation protocols, groups 1, 3 and 5 were submitted to 3 protocols: (NI) No irrigation (n = 2); (CI) conventional irrigation (n = 4), and (EndoVac) irrigation (n = 4). The samples were scanned by microcomputed tomography and prepared for scanning electron microscopy evaluation. Quantitative data were evaluated using the parametric ANOVA test, with statistical significance level set at 5%, and qualitative data obtained were compared to establish the agreement between examiners through the Kappa test. It was observed that in the analysis of XP-endo Shaper protocols, the additional working time did not cause difference in any of parameters evaluated (p > 0.05) in relation to time recommended by manufacturer. Compared to Hyflex, XP-K showed highest mean volume increase (p < 0.05) and lowest percentage of untouched walls (p < 0.05). In the qualitative evaluation, final irrigation protocol with EndoVac provided the best cleaning results when associated with XP-K and with Hyflex. Thus, supplementary techniques are effective tools to enhance cleaning and to promote higher touch of walls during root canal preparation.
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Cavidade Pulpar , Temperatura Alta , Humanos , Cavidade Pulpar/diagnóstico por imagem , Microtomografia por Raio-X , Preparo de Canal Radicular , LigasRESUMO
This study evaluate the maxillary anterior teeth anatomy by micro-computed tomography (µCT), about relevant characteristic for endodontic treatment planning. Fifty maxillary central incisors (MCI), lateral incisors (MLI) and maxillary canines (MC) were scanned using a µCT device. Two and three-dimensional parameters at 1 to 5mm distance to the apical foramen, external anatomic characteristics of the teeth and qualitative analysis of the internal anatomy was performed. The roundness and form factor values revealed a circular canal in the apical third in the MCI and MC, whereas MLI showed flattening in the apical third. The linear regression test indicated a progressive increase in the major/minor diameters in the five mm assessed (p < 0.001). The 3D analysis revealed the greatest volume and surface area in MC. The SMI showed a cylindrical geometry of root canals. All teeth presented Vertucci's type I root canal configuration. A mild curvature was prevalent in the MCI (45%) and a moderate one 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 most common exit of main apical foramen was in a central (22%), distolingual (30%) and mesiobuccal position (28%) for MCI, MLI and MC, respectively. Radicular grooves were observed in 2% of MCI and 4% of MLI. Two and three-dimensional data obtained by µCT allowed to observe morphological characteristics of internal/external anatomy of the maxillary anterior teeth. These characteristics may affect the endodontic treatment planning.
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Cavidade Pulpar , Raiz Dentária , Dente Canino , Cavidade Pulpar/diagnóstico por imagem , Humanos , Ápice Dentário , Microtomografia por Raio-XRESUMO
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.
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Cavidade Pulpar/anatomia & histologia , Microtomografia por Raio-X/métodos , Cavidade Pulpar/diagnóstico por imagem , Humanos , Imageamento Tridimensional , Mandíbula/anatomia & histologia , Mandíbula/diagnóstico por imagem , Maxila/anatomia & histologia , Maxila/diagnóstico por imagem , Valores de Referência , Estatísticas não Paramétricas , Ápice Dentário/anatomia & histologia , Ápice Dentário/diagnóstico por imagemRESUMO
The aim of this study was to evaluate the antibacterial potential of a calcium silicate-based sealer (Bio-C Sealer, Angelus) against common bacteria in primary and secondary endodontic infections. Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus mutans were exposed to fresh Bio-C Sealer for 24 h by the agar diffusion method (n=5). Additionally, the antibacterial activity was investigated against E. faecalis and S. mutans biofilms (48 h old) grown in discs with 4 mm in diameter and 2 mm in height. (n=3) of set discs of Bio-C Sealer (Angelus), EndoFill (Dentsply-Mallefer), Sealer 26 (Dentsply), AH Plus (Dentsply), Sealapex (Sybron-Endo) and EndoSequence BC Sealer (Brasseler). The antibacterial activity was evaluated by colony forming unity (CFU) counting using ImageJ software. Data were compared by one-way ANOVA followed by Holm-Sidak test (a=5%). Fresh Bio-C Sealer exhibited antimicrobial activity against all bacteria evaluated by agar diffusion method, except for S. mutans. Set discs of all endodontic sealers tested showed similar CFU values for E. faecalis (p>0.05). S. mutans in biofilms showed higher susceptibility to EndoFill compared with the other sealers (p<0.05). In conclusion, the results indicate that fresh Bio-C Sealer does not inhibit S. mutans growth, but exhibits antibacterial activity against E. faecalis, S. aureus, P. aeruginosa and E. coli. After setting, the Bio-C Sealer exhibits an antimicrobial potential comparable to that of the other sealers evaluated in E. faecalis biofilm, but lower than that of EndoFill for S. mutans biofilm.
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Resinas Epóxi , Materiais Restauradores do Canal Radicular , Antibacterianos/farmacologia , Compostos de Cálcio , Enterococcus faecalis , Escherichia coli , Teste de Materiais , Materiais Restauradores do Canal Radicular/farmacologia , Silicatos/farmacologia , Staphylococcus aureusRESUMO
INTRODUCTION: Endodontically treated teeth have an increased risk of biomechanical failure because of significant loss of tooth structure. The biomechanical behavior of endodontically treated teeth restored was evaluated using different extensions of endocrowns inside the pulp chamber by in vitro and 3-dimensional finite element analysis (FEA). METHODS: Thirty mandibular human molars were endodontically treated. Standardized endocrown preparations were performed, and the teeth were randomly divided into 3 groups (n = 10) according to different endocrown extensions inside the pulp chamber: G-5 mm, a 5-mm extension; G-3 mm, a 3-mm extension; and G-1 mm, a 1-mm extension. After adhesive cementation, all specimens were subjected to thermocycling and dynamic loading. The survival specimens were subjected to fracture resistance testing at a crosshead speed of 1 mm/min in a universal testing machine. All fractured specimens were subjected to fractography. Data were analyzed by 1-way analysis of variance and the Tukey post hoc test (P < .05). Stress distribution patterns in each group were analyzed using FEA. Qualitative analyses were performed according to the von Mises criterion. RESULTS: After dynamic loading, a survival rate of 100% was observed in all groups. For static loading, statistically significant differences among the groups were observed (P < .05) (G-5 mm = 2008.61 N, G-3 mm = 1795.41 N, and G-1 mm = 1268.12 N). Fractography showed a higher frequency of compression curls for G-5 mm and G-3 mm than for G-1 mm. FEA explained the results of fracture strength testing and fractography. CONCLUSIONS: Greater extension of endocrowns inside the pulp chamber provided better mechanical performance.
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Coroas , Cimentação/métodos , Coroas/efeitos adversos , Planejamento de Prótese Dentária , Falha de Restauração Dentária , Restauração Dentária Permanente/efeitos adversos , Restauração Dentária Permanente/métodos , Análise do Estresse Dentário , Análise de Elementos Finitos , Humanos , Técnicas In Vitro , Dente Molar/cirurgia , Dente não Vital/diagnóstico por imagem , Microtomografia por Raio-XRESUMO
Computer-aided design and computer-aided manufacturing (CAD-CAM) technology may be used to produce custom intraradicular posts, but studies are lacking. The purpose of this in vitro study was to evaluate the flexural properties (strength and modulus), failure mode, superficial morphology, and roughness of two CAD-CAM glass fiber posts (milled at different angulations) compared with a commercially available prefabricated glass fiber post. Three groups were tested (nâ¯=â¯10): PF (control group)- prefabricated glass fiber post; C-Cd-diagonally milled post; and C-Cv-vertically milled post. A 3-dimensional virtual image was obtained from a prefabricated post, which guided the posterior milling of posts from a glass fiber disk (Trilor Blanks; Bioloren). Surface roughness and morphology were evaluated using confocal laser microscopy. Flexural strength and modulus were evaluated with the 3-point bend test. Data were submitted to one-way analysis of variance followed by the Student-Newman-Keuls post hoc test (αâ¯=â¯0.05). The fractured surfaces were evaluated with scanning electron microscopy. The superficial roughness was highest for PF and similar for the experimental groups. Morphological analysis shows different sizes and directions of the glass fibers along the post. The flexural strength was highest for PF (900.1⯱â¯30.4â¯> C-Cd - 357.2⯱â¯30.7â¯> C-Cv 101.8⯱â¯4.3â¯MPa) as was the flexural modulus (PF 19.3⯱â¯2.0â¯GPa > C-Cv 10.1⯱â¯1.9â¯GPa > C-Cd 7.8⯱â¯1.3â¯GPa). A CAD-CAM milled post seems a promising development, but processing requires optimizing, as the prefabricated post still shows better mechanical properties and superficial characteristics.
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Desenho Assistido por Computador , Vidro , Fenômenos Mecânicos , Teste de Materiais , Propriedades de SuperfícieRESUMO
OBJECTIVE: Lipomas are relatively uncommon tumours in the oral cavity; only 1% to 4% of cases occur at this site. In this study, we describe the clinical and histopathologic features of 6 cases of oral lipoma. MATERIALS AND METHODS: Between 1997 and 2005, the files for all cases of oral lipoma at the oral pathology division, University of Ribeirão Preto, São Paulo, Brazil, were retrieved for study. Clinical data were retrieved from patient records, and all cases were reviewed microscopically and classified. RESULTS: Of the 6 cases, 3 occurred in males and 3 in females; their mean age was 50.2 years (range: 28-78 years). Most cases affected the buccal mucosa and the mean size of the tumours was 3.0 cm (range: 1.5-5.0 cm). Microscopically, 4 cases were classified as lipoma, 1 as fibrolipoma and 1 as intramuscular or infiltrative lipoma. All cases had been treated by simple surgical excision and there had been no recurrence after a mean treatment time of 50.3 months (range: 8-72 months). CONCLUSION: Oral lipomas are uncommon tumours that predominantly affect the buccal mucosa and are associated with an excellent prognosis.
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Lipoma/patologia , Neoplasias Bucais/patologia , Adulto , Idoso , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
To assess the physicochemical properties of AH Plus, GuttaFlow 2, GuttaFlow BioSeal, and MM Seal, five samples of each root canal sealer were evaluated to determine their setting time (ST), dimensional change (DC), solubility (SL), flow (FL), and radiopacity (RD) according to American National Standards Institute/American Dental Association (ANSI/ADA) Specification 57. The distilled and deionized water obtained from the SL test were subjected to atomic absorption spectrometry to observe the presence of Ca2+, K+, and Na+ ions. Statistical analysis was performed by using one-way ANOVA and Tukey-Kramer tests (p < 0.05). The following results were obtained: ST (min) (AH Plus 463.6 ± 13.22; GuttaFlow 2 24.35 ± 2.78; GuttaFlow Bioseal 17.4 ± 0.55; MM Seal 47.60 ± 4.39), DC (%) (AH Plus 0.06 ± 0.12; GuttaFlow 2 -26.06 ± 1.24; GuttaFlow Bioseal 2.10 ± 1.47; MM Seal 8.47 ± 2.41), SL (%) (AH Plus 0.41 ± 0.21; GuttaFlow 2 5.13 ± 4.11; GuttaFlow Bioseal 3.03 ± 1.05; MM Seal 0.94 ± 0.17), FL (mm) (AH Plus 36.42 ± 0.40; GuttaFlow 2 36.44 ± 0.05; GuttaFlow Bioseal 35.4 ± 0.03; MM Seal 52.75 ± 0.60), and RD (mmAl) (AH Plus 7.52 ± 1.59; GuttaFlow 2 6.85 ± 0.14; GuttaFlow Bioseal 7.02 ± 0.18; MM Seal 3.32 ± 0.90). ST, DC, SL, FL, and RD showed statistical differences among the root canal sealers (p < 0.05). As AH Plus showed the lowest DC and SL values (p < 0.05), the findings indicate that this sample is the only sealer conforming to ANSI/ADA standards.
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Dimetilpolisiloxanos/química , Resinas Epóxi/química , Guta-Percha/química , Materiais Restauradores do Canal Radicular/química , Silicones/química , Análise de Variância , Combinação de Medicamentos , Teste de Materiais , Valores de Referência , Solubilidade , Espectrofotometria Atômica , Estatísticas não Paramétricas , Propriedades de Superfície , Fatores de TempoRESUMO
The aim of this study was to evaluate morphological features of 70 single-rooted mandibular first premolars with radicular grooves (RG) using micro-CT technology. Teeth were scanned and evaluated regarding the morphology of the roots and root canals as well as length, depth and percentage frequency location of the RG. Volume, surface area and Structure Model Index (SMI) of the canals were measured for the full root length. Two-dimensional parameters and frequency of canal orifices were evaluated at 1, 2, and 3 mm levels from the apical foramen. The number of accessory canals, the dentinal thickness, and cross-sectional appearance of the canal at different root levels were also recorded. Expression of deep grooves was observed in 21.42% of the sample. Mean lengths of root and RG were 13.43 mm and 8.5 mm, respectively, while depth of the RG ranged from 0.75 to 1.13 mm. Mean canal volume, surface area and SMI were 10.78 mm3, 58.51 mm2, and 2.84, respectively. Apical delta was present in 4.35% of the sample and accessory canals were observed mostly at the middle and apical thirds. Two-dimensional parameters indicated an oval-shaped cross-sectional appearance of the root canal with a high percentage frequency of canal divisions (87.15%). Canal configuration type V (58.57%) was the most prevalent. C-shaped configuration was observed in 13 premolars (18.57%), whereas dentinal thickness ranged from 1.0 to 1.31 mm. Radicular grooves in mandibular first premolars was associated with the occurrence of several anatomical complexities, including C-shaped canals and divisions of the main root canal.
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Dente Pré-Molar/anatomia & histologia , Cavidade Pulpar/anatomia & histologia , Raiz Dentária/anatomia & histologia , Microtomografia por Raio-X/métodos , Humanos , MandíbulaRESUMO
Abstract This study evaluate the maxillary anterior teeth anatomy by micro-computed tomography (μCT), about relevant characteristic for endodontic treatment planning. Fifty maxillary central incisors (MCI), lateral incisors (MLI) and maxillary canines (MC) were scanned using a μCT device. Two and three-dimensional parameters at 1 to 5mm distance to the apical foramen, external anatomic characteristics of the teeth and qualitative analysis of the internal anatomy was performed. The roundness and form factor values revealed a circular canal in the apical third in the MCI and MC, whereas MLI showed flattening in the apical third. The linear regression test indicated a progressive increase in the major/minor diameters in the five mm assessed (p < 0.001). The 3D analysis revealed the greatest volume and surface area in MC. The SMI showed a cylindrical geometry of root canals. All teeth presented Vertucci's type I root canal configuration. A mild curvature was prevalent in the MCI (45%) and a moderate one 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 most common exit of main apical foramen was in a central (22%), distolingual (30%) and mesiobuccal position (28%) for MCI, MLI and MC, respectively. Radicular grooves were observed in 2% of MCI and 4% of MLI. Two and three-dimensional data obtained by μCT allowed to observe morphological characteristics of internal/external anatomy of the maxillary anterior teeth. These characteristics may affect the endodontic treatment planning.
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Abstract This study evaluate shaping ability of heat-treated NiTi-alloy instruments associated with different final irrigation protocols in flattened root canals. Thirty human mandibular incisors with flattened root canals were divided into 5 groups (n = 10): (XP) Original Protocol XP-endo Shaper; (XP-WT) Original Protocol XP-endo Shaper with working time variation; (XP-K) XP-endo Shaper with kinematics variation; (XP-WTK) XP-endo Shaper with kinematics and working time variations; (Hyflex) Hyflex CM. For the variation in working time protocols the same sample of the XP-endo Shaper groups with and without kinematic variation were used. To evaluate final irrigation protocols, groups 1, 3 and 5 were submitted to 3 protocols: (NI) No irrigation (n = 2); (CI) conventional irrigation (n = 4), and (EndoVac) irrigation (n = 4). The samples were scanned by microcomputed tomography and prepared for scanning electron microscopy evaluation. Quantitative data were evaluated using the parametric ANOVA test, with statistical significance level set at 5%, and qualitative data obtained were compared to establish the agreement between examiners through the Kappa test. It was observed that in the analysis of XP-endo Shaper protocols, the additional working time did not cause difference in any of parameters evaluated (p > 0.05) in relation to time recommended by manufacturer. Compared to Hyflex, XP-K showed highest mean volume increase (p < 0.05) and lowest percentage of untouched walls (p < 0.05). In the qualitative evaluation, final irrigation protocol with EndoVac provided the best cleaning results when associated with XP-K and with Hyflex. Thus, supplementary techniques are effective tools to enhance cleaning and to promote higher touch of walls during root canal preparation.
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INTRODUCTION: Metallic antibacterial nanoparticles have been shown to provide distinct antibacterial advantage and antibiofilm efficacy when applied in infected root canals. The purpose of this study was to evaluate the influence of incorporating zinc oxide nanoparticles (ZnO-Np) on the physicochemical properties of Grossman sealer. METHODS: Grossman sealer was prepared according to its original formula. Additionally, 4 experimental sealers were prepared by replacing the zinc oxide component of the powder with ZnO-Np (average size of 20 nm) in different amounts (25%, 50%, 75%, and 100%). Characterization of the setting time, flow, solubility, dimensional changes, and radiopacity were performed according to American National Standards Institute (ANSI)/American Dental Association (ADA) Specification 57. Scanning electron microscopic and energy-dispersive X-ray spectroscopic analyses were conducted to assess the ultrastructural and chemical characteristics of experimental sealers subjected to the solubility test. Statistical analyses were performed with analysis of variance and post hoc Tukey-Kramer tests with a significance level of 5%. RESULTS: A statistically significant difference in the setting time was observed among groups (P < .05), but only 25% ZnO-Np sealer complied with ANSI/ADA requirements. There was a significant difference in the flow characteristics between the control and 25% and 75% ZnO-Np experimental sealers (P < .05), but all sealers conformed to ANSI/ADA standardization; 25% ZnO-Np sealer showed significantly less solubility (1.81% ± 0.31%) and dimensional change (-0.34% ± 0.12%) than other sealers (P < .05). All sealers showed ultrastructural changes with increasing solubility. CONCLUSIONS: ZnO-Np decreased the setting time and dimensional changes characteristic of Grossman sealer; 25% ZnO-Np improved the physicochemical properties of Grossman sealer in accordance with ANSI/ADA requirements.
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Fenômenos Químicos , Nanopartículas/química , Materiais Restauradores do Canal Radicular/química , Cimento de Óxido de Zinco e Eugenol/química , Óxido de Zinco/química , Resinas Acrílicas , Teste de Materiais , Microscopia Eletrônica de Varredura , Solubilidade , Propriedades de Superfície , Fatores de TempoRESUMO
The aim of the present study was to evaluate the bond strength (BS) of root canal fillings to root dentin using the reciprocating file-matched single-cone or lateral compaction techniques with resin-based and calcium-silicate-based sealers. Maxillary canine roots were prepared and filled using one of the following approaches: Reciproc R40 file and R40 single cone, WaveOne Large file and Large single cone, or ProTaper up to F4 file with lateral compaction. The root filling was performed using AH Plus, Epiphany SE or MTA Fillapex (n = 10). Three 1-mm-thick slices were obtained from each third of each root. Two slices were subjected to a push-out test, and the other slices were prepared for scanning electron microscopy (SEM) to examine the dentin-sealer interface. Data (in MPa) from the push-out tests were analyzed using a two-way ANOVA and Tukey's test (p < 0.05). Failure modes (adhesive, cohesive or mixed) were evaluated at ×25 magnification. The single-cone techniques resulted in lower BS values than the lateral compaction technique. For lateral compaction, AH Plus and Epiphany SE showed the highest and lowest BS values, respectively. Slight differences were observed between sealers when the single-cone techniques were used. A tendency to reduce the BS toward the apical third was observed. Adhesive failures were predominant for all experimental conditions. A closer adaption of the filling material on the root dentin was observed for the AH Plus and lateral compaction techniques. The Reciproc and WaveOne techniques were associated with lower BS values than the lateral compaction technique. However, the effect of the root canal filling technique appears to be sealer-dependent.
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Colagem Dentária/instrumentação , Materiais Restauradores do Canal Radicular/química , Preparo de Canal Radicular/instrumentação , Compostos de Alumínio/química , Análise de Variância , Compostos de Cálcio/química , Colagem Dentária/métodos , Falha de Restauração Dentária , Dentina/efeitos dos fármacos , Combinação de Medicamentos , Resinas Epóxi/química , Desenho de Equipamento , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Níquel/química , Óxidos/química , Reprodutibilidade dos Testes , Obturação do Canal Radicular/instrumentação , Obturação do Canal Radicular/métodos , Preparo de Canal Radicular/métodos , Silicatos/química , Propriedades de Superfície , Titânio/químicaRESUMO
Abstract The aim of this study was to evaluate the antibacterial potential of a calcium silicate-based sealer (Bio-C Sealer, Angelus) against common bacteria in primary and secondary endodontic infections. Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus mutans were exposed to fresh Bio-C Sealer for 24 h by the agar diffusion method (n=5). Additionally, the antibacterial activity was investigated against E. faecalis and S. mutans biofilms (48 h old) grown in discs with 4 mm in diameter and 2 mm in height. (n=3) of set discs of Bio-C Sealer (Angelus), EndoFill (Dentsply-Mallefer), Sealer 26 (Dentsply), AH Plus (Dentsply), Sealapex (Sybron-Endo) and EndoSequence BC Sealer (Brasseler). The antibacterial activity was evaluated by colony forming unity (CFU) counting using ImageJ software. Data were compared by one-way ANOVA followed by Holm-Sidak test (a=5%). Fresh Bio-C Sealer exhibited antimicrobial activity against all bacteria evaluated by agar diffusion method, except for S. mutans. Set discs of all endodontic sealers tested showed similar CFU values for E. faecalis (p>0.05). S. mutans in biofilms showed higher susceptibility to EndoFill compared with the other sealers (p<0.05). In conclusion, the results indicate that fresh Bio-C Sealer does not inhibit S. mutans growth, but exhibits antibacterial activity against E. faecalis, S. aureus, P. aeruginosa and E. coli. After setting, the Bio-C Sealer exhibits an antimicrobial potential comparable to that of the other sealers evaluated in E. faecalis biofilm, but lower than that of EndoFill for S. mutans biofilm.
Resumo O objetivo deste estudo foi avaliar o potencial antibacteriano do novo cimento biocerâmico (Bio-C Sealer, Angelus) contra bactérias comuns em infecções endodônticas primárias e secundárias. Culturas de Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus e Streptococcus mutans foram expostos a amostras frescas do Bio-C sealer durante 24 h pelo método de difusão em agar (n=5). A atividade antibacteriana de amostras dos cimentos Bio-C Sealer (Angelus), EndoFill (Dentsply-Mallefer), Sealer 26 (Dentsply), AH Plus (Dentsply), Sealapex (Sybron-Endo) e EndoSequence BC Sealer (Brasseler) após a presa também foi investigada em biofilmes de 48 h das bactérias E. faecalis e S. mutans, crescidos em discos com 4 mm de diâmetro e 2 mm de altura. A atividade antibacteriana foi avaliada por contagem das unidades formadoras de colônias (UFC) utilizando o software ImageJ. Os dados foram comparados por ANOVA a um critério seguido pelo pós-teste Holm-Sidak (a=5%). Amostras frescas do Bio-C Sealer exibiram atividade antimicrobiana contra todas as bactérias avaliadas pelo método de difusão em ágar, exceto para S. mutans. A análise da formação de biofilme mostrou que todos os cimentos endodônticos testados apresentaram valores similares de UFC para E. faecalis (p> 0,05), enquanto biofilmes de S. mutans foram mais suscetíveis ao EndoFill em comparação com os demais cimentos (p<0,05). Conclui-se que o cimento Bio-C Sealer fresco exibe atividade antibacteriana para E. faecalis, S. aureus, P. aeruginosa e E. coli, mas não inibe o crescimento de S. mutans. Após a presa, o cimento Bio-C Sealer exibe potencial antimicrobiano similar ao dos demais cimentos avaliados em biofilme de E. faecalis, mas inferior ao do EndoFill para S. mutans.
Assuntos
Materiais Restauradores do Canal Radicular/farmacologia , Resinas Epóxi , Staphylococcus aureus , Teste de Materiais , Enterococcus faecalis , Silicatos/farmacologia , Compostos de Cálcio , Escherichia coli , Antibacterianos/farmacologiaRESUMO
Abstract 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.
Assuntos
Humanos , Cavidade Pulpar/anatomia & histologia , Microtomografia por Raio-X/métodos , Valores de Referência , Estatísticas não Paramétricas , Ápice Dentário/anatomia & histologia , Ápice Dentário/diagnóstico por imagem , Imageamento Tridimensional , Cavidade Pulpar/diagnóstico por imagem , Mandíbula/anatomia & histologia , Mandíbula/diagnóstico por imagem , Maxila/anatomia & histologia , Maxila/diagnóstico por imagemRESUMO
INTRODUCTION: This study compared the bond strength, interfacial ultrastructure, and tag penetration of resin-based sealers applied to smear-free radicular dentin using 70% isopropyl alcohol as the active final rinse. METHODS: Eighty root canals were prepared and assigned to 2 groups (n = 40) according to the drying protocol: paper points or 70% isopropyl alcohol. Then, roots were divided into 4 subgroups (n = 10) with respect to the sealer and obturation material: AH Plus (Dentsply De Trey GmbH, Konstanz, Germany) and gutta-percha (AH/GP), Hybrid Root SEAL (Sun Medical, Tokyo, Japan) and gutta-percha (HR/GP), Epiphany SE (Pentron Clinical Technologies, Wallingford, CT) and gutta-percha (EP/GP), and Epiphany SE and Resilon (EP/RS). Roots were sectioned, and the push-out test was performed. Failure modes were examined under stereomicroscopy and sealer penetration into the dentinal tubules under scanning electron microscopy. Data were statistically analyzed by 2-way analysis of variance post hoc Tukey tests with a significant level of 5%. RESULTS: Overall, canals dried with isopropyl alcohol showed significantly higher bond strength values (2.11 ± 1.74 MPa) than with paper points (1.81 ± 1.73 MPa) (P < .05). The HR/GP group showed lower bond strength than the AH/GP group (P < .05) but higher than the EP/GP and EP/RS groups (P < .05). The most frequent type of failure was cohesive in the AH/GP and HR/GP groups and adhesive in the EP/GP and EP/RS groups. Scanning electron microscopic evaluation revealed better adaptation of the adhesive interface in the AH/GP and HR/GP groups in comparison with the EP/GP and EP/RS groups. CONCLUSIONS: A final rinse with EDTA and 70% isopropyl alcohol improved the bond strength and penetration of the sealers into dentinal tubules of the root.
Assuntos
2-Propanol/química , Colagem Dentária/métodos , Cavidade Pulpar/ultraestrutura , Dentina/ultraestrutura , Higroscópicos/química , Cimentos de Resina/química , Materiais Restauradores do Canal Radicular/química , Adesividade , Dessecação , Ácido Edético/química , Resinas Epóxi/química , Guta-Percha/química , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Papel , Distribuição Aleatória , Preparo de Canal Radicular/instrumentação , Preparo de Canal Radicular/métodos , Estresse Mecânico , Propriedades de SuperfícieRESUMO
INTRODUCTION: Cleaning and shaping of root canals are essential steps for the success of endodontic therapy. The purpose of this study was to evaluate the tissue debridement efficacy of the self-adjusting file (SAF) protocol in the apical third of oval-shaped canals of mandibular incisors in comparison with a nickel-titanium rotary system preparation. METHODS: Twenty-six single-rooted human mandibular incisor teeth were selected and assigned to a control (n = 4) and 2 experimental groups (n = 11) according to 1 of 2 instrumentation techniques, SAF and nickel-titanium rotary systems. After root canal preparation, the apical thirds of the specimens were submitted to histologic processing and analyzed by optical microscopy regarding the percentage of debris and uninstrumented root canal walls. The data were statistically compared by using unpaired t test with Welch's correction, and the level of significance was set at 5%. RESULTS: The percentage of remaining debris and uninstrumented canal perimeter was significantly lower in SAF group (2.18 ± 2.71 and 12.33 ± 7.85, respectively) than in rotary group (13.11 ± 12.98 and 53.54 ± 15.95, respectively) (P < .05). In the SAF group most of specimens were completely free of debris, whereas in the rotary group 53% of the canals presented debris. CONCLUSIONS: SAF had significantly more contact to the dentin walls and removed more debris than rotary instrumentation in the apical third of mandibular incisors.