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Background and Objectives: The insertion of the dental implant in the bone is an essential step in prosthetic rehabilitation. The insertion torque has the potential to distort the prosthetic platform, which can cause future biomechanical problems with the continuous action of occlusal forces. The aim of this study is to evaluate different insertion torques in the deformation of tri-channel platform connections through two- and three-dimensional measurements with micro-CT. Materials and Methods: A total of 164 implants were divided into groups (platform diameter and type): 3.5, 3.75, and 4.3 mm NP (narrow platform), and 4.3 mm RP (regular platform). Each implant-platform group was then divided into four subgroups (n = 10) with different torques: T45 (45 Ncm), T80 (80 Ncm), T120 (120 Ncm), and T150 (150 Ncm). The implant-abutment-screw assemblies were scanned and the images obtained were analyzed. Results: A significant difference was observed for the linear and volume measures between the different platforms (p < 0.01) and the different implant insertion torques (p < 0.01). Qualitative analysis suggested a higher deformation resistance for the 3.75 NP compared to the 3.5 NP, and RP was more resistant compared to the NP. Conclusions: The 0.25 mm increment in the implant platform did not increase the resistance to the applied insertion torques; the 4.3 mm implant was significantly stronger compared to the 3.5 mm implant; and the proposed micro-CT analysis was considered valid for both the 2D and 3D analyses of micro-gaps, qualitatively and quantitatively.
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Próteses e Implantes , Humanos , Microtomografia por Raio-X , TorqueRESUMO
OBJECTIVES: This study aimed to evaluate the effects of different shaping protocols on the root canal geometry and remaining dentin thickness of mandibular premolars with radicular grooves (RG) and two canals by means of micro-CT. MATERIALS AND METHODS: Mandibular premolars with RG and two canals were matched based on their similar morphological dimensions and assigned to 2 experimental groups according to the canal preparation (n=8): XP-endo Shaper (XPS) and ProTaper Next (PTN) systems. Before and after preparation, morphometric measurements of the volume, surface area, structure model index, area, perimeter, roundness, major and minor diameters, as well as untouched canal walls, canal transportation, and dentin wall thickness were evaluated. Data were statistically compared within and between groups using the independent sample t test (α=5%). RESULTS: XPS revealed less changes in volume, surface area, area, perimeter, and major and minor diameters (P<0.05). There was no significant difference in structure model index (SMI), roundness, and percentage of untouched canal walls between groups (P>0.05). XPS resulted in less apical canal transportation and a higher remaining dentin thickness toward the RG compared to PTN in lingual canals (P<0.05). CONCLUSIONS: XPS revealed fewer changes in root canal geometry as well as lower transportation and a greater remaining dentin thickness in the lingual canals toward the RG compared to PTN. CLINICAL RELEVANCE: Internal and external anatomical characteristics of mandibular premolars might have an influence on biomechanical preparation. Considering the risk of perforation, the canal preparation using XPS appears to be more conservative compared to PTN.
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Cavidade Pulpar , Preparo de Canal Radicular , Dente Pré-Molar/diagnóstico por imagem , Cavidade Pulpar/diagnóstico por imagem , Dentina/diagnóstico por imagem , Desenho de Equipamento , Humanos , Microtomografia por Raio-XRESUMO
External root resorptions are characterized by progressive destruction of hard tissue due to clastic activity. This article reports 2 cases that involved the nonsurgical treatment of mandibular molars with idiopathic external root resorption. In the first case, clinical and radiographic examination showed irreversible inflammation of the pulp tissue and resorption of the distal root. Chronic inflammatory infiltrate and necrosis were identified by histopathologic examination of the pulp tissue. In the second case, inadequate endodontic treatment and a resorptive process were observed in the mesial and distal roots. In both cases, mineral trioxide aggregate (MTA) was used as the filling material. Clinical and radiographic follow-ups of 1 and 7 years, respectively, showed a favorable trend, including interruption of the resorptive process and periradicular normality. More longitudinal studies are necessary to analyze the performance of MTA in treating external root resorptions.
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Reabsorção da Raiz/diagnóstico , Adulto , Compostos de Alumínio/uso terapêutico , Compostos de Cálcio/uso terapêutico , Combinação de Medicamentos , Feminino , Humanos , Masculino , Dente Molar , Óxidos/uso terapêutico , Radiografia Dentária , Materiais Restauradores do Canal Radicular/uso terapêutico , Tratamento do Canal Radicular/métodos , Reabsorção da Raiz/diagnóstico por imagem , Reabsorção da Raiz/patologia , Reabsorção da Raiz/terapia , Silicatos/uso terapêutico , Adulto JovemRESUMO
OBJECTIVES: This study aims to identify the two-dimensional and three-dimensional analyses and evaluate the loss of tooth structure in the tooth's different constituent elements and the ceramic antagonist's surface. METHODS: In this study, three groups (n = 10) represented by different ceramic systems (lithium disilicate [GDis], lithium silicate reinforced with zirconia [GSil], and monolithic zirconia [GZir]) were evaluated. Each group obtained ten ceramic blocks and submitted them to the sintering/crystallization process. To carry out the wear test, healthy mandibular premolars were used as the specimens and the ceramic blocks as antagonists. The premolars were submitted to two-dimensional and three-dimensional analyses using a computerized microtomography (µTC) before and after the wear test. The wear test was performed with 30 N and 300,000 cycles load, with occlusion, laterality, and disocclusion movements. RESULTS: The statistical analysis comparing the loss of two-dimensional tooth structure showed a statistically significant difference among all groups (p < 0.05). Statistical analysis comparing the percentage of loss of three-dimensional tooth structure showed a statistically significant difference between groups GDis and GSil and between groups GDis and GZir. However, when comparing GSil with GZir, no statistically significant difference was found. The qualitative analysis of the teeth showed that GDis showed considerable enamel loss and dentin exposure, GSil showed enamel wear with flattening the cusp without dentin exposure, and GZir showed minimal enamel wear without dentin exposure. In the qualitative analysis of ceramic antagonists, more significant wear of the ceramic material for GDis was observed, followed by the GSil and GZir groups, respectively. SIGNIFICANCE: The use of the lithium disilicate should be cautious, restricting it to areas with lower masticatory forces. Areas of higher masticatory forces showed a large amount of antagonist wear, with dentin involvement. This can lead to dentinal hypersensitivity, risk of compromising patients' occlusion, by harming group disocclusion guides, causing pain and temporomandibular disorders.
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Desgaste dos Dentes , Humanos , Teste de Materiais , Porcelana Dentária/química , Cerâmica/química , Zircônio/química , Inibidores de Dissociação do Nucleotídeo Guanina , Propriedades de SuperfícieRESUMO
OBJECTIVES: This study aimed to evaluate the level of knowledge, perception, and experience of teledentistry amongst Brazilian dentists with the ongoing COVID-19 pandemic. METHODS: Between June and July 2020, an online questionnaire was used to collect information on the demographic and professional profiles of dentists and their levels of knowledge, perception, and attitudes towards teledentistry. Descriptive statistics were reported as percentages, and Chi-squared test was used to compare responses amongst general practitioners, specialists, and those with varying levels of professional experience. RESULTS: This study included 575 dentists, the majority of whom were from the southeast region of Brazil (73.4%) and had a specialist degree (70.4%). Approximately 42.4% of the study sample had graduated more than 10 years ago, 39.3% between 2 and 10 years ago, and 18.3% up to 2 years ago. In general, the majority of dentists exhibited only a superficial awareness of the resolution that regulates teledentistry in Brazil. A greater number of specialists were aware of the resolution (P = .007) and felt confident performing teledentistry (P = .000) compared to general practitioners, whilst those with more experience (graduated more than 10 years ago) exhibited greater knowledge (P = .012) and preparation (P = .000). More than 60% of the dentists, regardless of dental specialty and clinical experience, had no knowledge of providing prescriptions via teledentistry. The majority of general practitioners (89.5%) and specialists (81.4%) had no previous experience using teledentistry. CONCLUSIONS: The findings of this study suggest that Brazilian dentists are inadequately prepared for the implementation of teledentistry.
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COVID-19 , Odontólogos , Humanos , Pandemias , Percepção , Inquéritos e QuestionáriosRESUMO
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
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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INTRODUCTION: The purpose of this study was to evaluate the impact of conservative endodontic cavities (CECs) on root canal preparation, restoration, and biomechanical behavior of teeth prepared using different shaping systems and restorative materials. METHODS: Ninety upper premolars with a bifurcated root were matched based on morphology and randomly assigned to a control group (n = 10) or 1 of the following experimental groups (n = 40): traditional endodontic cavity and CEC. Teeth were subdivided according to instrumentation (n = 10) as follows: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (VDW GmbH, Munich, Germany), Reciproc Blue (VDW GmbH), and Hyflex EDM (Coltene/Whaledent, Altstätten, Switzerland). After canal obturation, teeth were restored using temporary material, conventional composite, regular bulk fill composite, or bulk fill flow combined with conventional composite. Before and after preparation and after obturation, the teeth were scanned using micro-computed tomographic imaging. Canal transportation (CT), the percentage of untouched canal surfaces (UCSs), voids in restoration (VRs), and residual filling material in the pulp chamber were evaluated. Finite element analysis, fracture resistance, and the failure pattern were recorded. The data were analyzed using analysis of variance and the Tukey and chi-square tests. RESULTS: CECs had greater CT, percentage of filling material, and VRs compared with traditional endodontic cavities (P < .0001). The highest CT and UCSs were observed in CEC with ProTaper Universal. Bulk fill flow combined with conventional composite showed a lower percentage of VRs compared with other restorative materials (P < .05). Finite element analysis, fracture resistance, and failure pattern revealed similar behaviors in all groups (P > .05) . CONCLUSIONS: CECs had a negative impact on root canal centralization, UCSs, cleaning of the pulp chamber, and percentage of VRs. Controlled memory instruments were the most adequate for the root canal preparation of CECs. The endodontic cavity did not influence the biomechanical behavior of restored teeth.
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Cavidade Pulpar , Preparo de Canal Radicular , Dente Pré-Molar , Cavidade Pulpar/diagnóstico por imagem , Alemanha , Tratamento do Canal RadicularRESUMO
This study aimed to describe the morphometric relationship of root canal orifices on the pulp floor in the presence/absence of mesiobuccal second canal (MB2) in the maxillary first molars and other aspects of its internal anatomy. Sixty-two maxillary first molars were scanned by micro-CT. The presence of the MB2 canal was verified. The distance between the center points of the MB1, MB2, distobuccal (DB), and palatal (P) canal orifices on the pulp floor were measured (MB1-MB2, MB1-DB, MB2-DB, MB1-P, and DB-P). The MB1-P to DB-P ratio was calculated. The distances between the anatomic apex and the MB1 and MB2 apical foramina were measured. The length of the band-shaped isthmus was also measured. Student's t-test was applied to verify the association between the presence of an MB2 canal, the interorifice distances, and the ratio of the MB1-P to DB-P distance (α = 5%). The MB2 canal was present in 43 roots (69.35%). Statistics showed significant differences when MB2 was present for the largest MB1-P distance (p < 0.05) and higher values for the MB1-P to DB-P ratio (p < 0.05). A band-shaped isthmus was detected in 25.8% of MB roots. The mean distance from the apical foramen to the isthmus floor ranged from 1.74 for MB1 canals to 1.42 for MB2 canals. Canal orifice distances on the pulp floor may predict the presence of MB2 canals. There was a high incidence of isthmus, accessory canals, and apical delta in the critical apical zone in MB roots of maxillary first molars.
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Maxila , Raiz Dentária , Cavidade Pulpar/diagnóstico por imagem , Humanos , Maxila/diagnóstico por imagem , Dente Molar/diagnóstico por imagem , Raiz Dentária/diagnóstico por imagem , Microtomografia por Raio-XRESUMO
This study evaluated by the efficacy of rotary and reciprocating systems to remove filling material by micro-CT. Sixty human canines were instrumented up to F3 by ProTaper Universal system and filled with AH Plus/ gutta-percha. Specimens were submitted to 1,200 thermal cycles, scanned by microCT SkyScan 1176 and randomly distributed in groups according to the filling material removal protocol (n = 10): ProTaper Universal, ProTaper Universal/xylol, ProTaper Next, ProTaper Next/xylol, Reciproc and Reciproc/xylol. After filling removal, specimens were analyzed by microCT to separately verify the presence of gutta-percha and sealer remnants. The data (mm3) were analyzed by two way ANOVA and Tukey´s test (5%). For the remaining gutta-percha, the use of xylol provided the highest values for Reciproc (7.60 ± 0.73), which was statistically different from the other groups (p < 0.05) that presented lower values and were statistically similar to each other (p > 0.05). For the remaining sealer, xylol provided the highest values (21.25 ± 6.94) different (p < 0.05) from the use of instruments alone (11.47 ± 9.45). ProTaper Next presented the lowest values (8.16 ± 1.37) for the remaining sealer, different (p < 0.05) from that of Reciproc (24.67 ± 6.32). The qualitative analysis revealed that all groups presented some remaining root filling material, with the highest volumes presented by Reciproc and Reciproc/xylol. In conclusion the rotary systems provided greater removal of filling material regardless of the use of xylol. The use of xylol negatively interfered with the action of the reciprocating system in the removal of the gutta-percha and sealer.
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Materiais Restauradores do Canal Radicular , Obturação do Canal Radicular , Cavidade Pulpar/diagnóstico por imagem , Guta-Percha , Humanos , Retratamento , Preparo de Canal Radicular , Solventes , Microtomografia por Raio-XRESUMO
This study evaluated the syringe/needle (SN), passive ultrasonic irrigation (PUI) and XP-endo Finisher (XP) in the removal of Ca(OH)2 -based paste and the bond strength (BS) values of an epoxy resin (AH Plus) and silicate (MTA)-based sealers to root dentin. Eighty lower premolars were assigned: control group (CT), SN, PUI and XP, and subdivided according to the sealer (n = 10) for BS. SN has the lowest removal followed by PUI and XP. AH Plus had higher BS for CT compared with SN in all root thirds. CT and XP presented similar BS in the apical and middle thirds and higher than SN and PUI. For MTA, similar BS was observed in the cervical and apical thirds, and in the middle third, CT, PUI and XP presented similar values and higher than SN. PUI and XP methods presented higher efficiency in the Ca(OH)2 removal, and the residual Ca(OH)2 provides a reduction in BS of the AH Plus.
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Hidróxido de Cálcio , Materiais Restauradores do Canal Radicular , Dente Pré-Molar , Resinas Epóxi , SilicatosRESUMO
This study evaluated the effect of chitosan, zirconium oxide, and hydroxyapatite on the apatite-like forming ability, porosity, and bond-strength of calcium-aluminate cements (C). Three hundred bovine root-slices were assigned to one of five groups, according to the material: MTA, C, C + chitosan (Cchi), C + zirconium oxide (Czio), and C + hydroxyapatite (Chap), and within each group, two subgroups, according to the immersion: deionized water or phosphate-buffered saline (PBS) up to 14 days. Assessments (n = 10) of apatite-like forming ability were performed using scanning-electron microscopy, energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, and x-ray diffraction. PBS was evaluated for pH and Ca2+ release (n = 10). Bond-strength was analyzed by push-out test (n = 10) and porosity by micro-CT (n = 10). Chemical and push-out data were analyzed by ANOVA and Tukey's tests (α = .05). Porosity data were analyzed by the Kruskal-Wallis and SNK tests (α = .05). Similar Ca/P ratios were observed between all groups (p > .05). The pH of MTA and Cchi were higher than that of other cements at d 3 and 6 (p < .05). Cchi had a higher release of Ca2+ up to 6 days (p < .05). All cements had lower porosity after PBS (p < .05). Cchi and Chap had similar porosity reduction (p > .05), and were higher than MTA, C, and Czio (p < .05). Cchi had higher bond-strength than the other groups (p < .05). PBS samples had higher bond-strength (p < .05). All cements had hydroxyapatite deposition and the chitosan blend had the lowest porosity and the highest bond-strength.
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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
INTRODUCTION: The aim of this study was to compare the shaping ability of 4 different nickel-titanium systems, considering their variation in alloy treatment, kinematics, and design, used to prepare canals with severe curvature using micro-computed tomographic analysis. METHODS: Thirty-two mesial roots of mandibular molars with severe curvature were matched based on similar morphologic dimensions and assigned to 4 experimental groups (n = 8) according to the canal preparation: ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (RC; VDW GmbH, Munich, Germany), Reciproc Blue (RCB, VDW GmbH), and TRUShape (TRU; Dentsply Tulsa Dental Specialties, Tulsa, OK) systems. Changes in 2-dimensional (area and perimeter) and 3-dimensional (volume, surface area, and structure model index) morphologic parameters as well as canal transportation were compared among groups using the analysis of variance post hoc Tukey tests with the significance level set at 5%. RESULTS: Preparation significantly increased all analyzed parameters. No statistically significant differences (P > .05) were observed between RC and RCB or between PTN and TRS in any of the analyzed parameters. In the cervical third, RC and RCB presented higher mean increases than PTN and TRU. In the apical third, there were no statistically significant differences (P > .05) among the systems. CONCLUSIONS: The instruments of greater taper may promote greater morphologic changes. However, regardless of the number of instruments (multiple or single), the type of movement (rotation or reciprocating), the type of heat treatment of alloys, and the particular characteristics of each instrument (taper and design), the evaluated systems did not result in different dimensional changes and canal transportation in the critical apical area.
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Cavidade Pulpar , Níquel , Preparo de Canal Radicular , Titânio , Ligas , Ligas Dentárias , Desenho de Equipamento , Temperatura Alta , Microtomografia por Raio-XRESUMO
This literature review has critically analyzed the published research related to the biomechanical preparation of root canals with three-dimensional analysis using micro-computed tomography (micro-CT). In December 2017, six databases (PubMed, Cochrane, Web of Science, Embase, Scopus, and Science Direct) were accessed using keywords to find articles including the use of the micro-CT analysis in biomechanical root canal preparation. There were 60 full articles that were selected, which were screened and read by two authors. The research that was reviewed and analyzed included root canal anatomy and sample selection, changes in canal shape and untouched canal areas, canal transportation and centering ability, and kinematics (motion). Of the studies selected, 49.18% discussed anatomical characteristics, with 54.1% of these studies describing mesial roots of mandibular molars with moderate curvature. Only 35% used a stratified distribution based on root canal system morphology and quantitative data obtained by micro-CT. The analysis of canal transportation and centering ability showed that transport values in the apical third exceeded the critical limit of 0.3 mm in mesial roots of mandibular molars with moderate curvature, especially in the groups in which a reciprocating system was used. In relation to kinematics, 91.70% of the reviewed studies evaluated continuous rotating instruments, followed by reciprocating rotation (38.33%), vibratory (15%), and the adaptive kinematics, which was in only 8.33%. The reciprocating kinematics was associated with higher canal decentralization and transportation indexes, as well as a greater capacity for dentin removal and debris accumulation. This literature review showed that the anatomy, the type of design and kinematics of instruments, and the experimental design are factors that directly influence the quality of biomechanical preparation of root canals analyzed in a qualitative and quantitative manner by micro-CT.
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Cavidade Pulpar/anatomia & histologia , Cavidade Pulpar/diagnóstico por imagem , Preparo de Canal Radicular/métodos , Microtomografia por Raio-X/métodos , Ligas , Instrumentos Odontológicos , Desenho de Equipamento , Humanos , Imageamento Tridimensional , Mandíbula , Dente Molar , Preparo de Canal Radicular/instrumentaçãoRESUMO
The effect of local delivery of strontium ranelate (SR) on bone regeneration of critical size bone defects filled with collagen sponge was evaluated. Bone defects of 5 mm diameter created in rat calvaria were filled with collagen sponge (C); collagen sponge with 5 mM Sr2+ SR (C5SR) or collagen sponge with 50 mM Sr2+ SR (C50SR). After 2, 4, and 6 weeks, bone volume (BV), bone surface (BS), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) were evaluated by computed microtomography. At 6 weeks, histological analysis was performed. Intragroup comparisons were made by the Friedman test, while comparisons between groups were made by Kruskal-Wallis test (α = 5%). All groups showed increased BV, BS, Tb.Th, and Tb.N over time, but only C50SR promoted the reduction of Tb.Sp (p < 0.05). No significant differences between groups were detected at weeks 2 and 4. However, C50SR showed the highest values of BV, BS, and Tb.Th at 6 weeks (p < 0.05). Histological analysis revealed connective tissue in C and C5SR and immature bone tissue in C50SR. Local delivery of SR 50 mM Sr2+ associated with collagen sponge increased and accelerated bone regeneration in critical bone defects. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 333-341, 2018.
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Regeneração Óssea/efeitos dos fármacos , Colágeno/química , Sistemas de Liberação de Medicamentos , Crânio/patologia , Tiofenos/farmacologia , Animais , Células Cultivadas , Masculino , Osteoblastos/efeitos dos fármacos , Osteoblastos/patologia , Ratos Wistar , Crânio/diagnóstico por imagem , Crânio/efeitos dos fármacos , Crânio/fisiopatologia , Microtomografia por Raio-XRESUMO
OBJECTIVE: The aim of this study was to evaluate bone mineral density (BMD) and microarchitecture in femurs and maxillary bones of ovariectomized (OVX) rats treated or not treated with alendronate (ALD) or odanacatib (ODN). STUDY DESIGN: Twenty rats were divided into groups: SHAM, OVX, OVX/ALD, and OVX/ODN. After 12 weeks, the femurs and maxillae were removed and subjected to 3-dimensional analysis by micro-computed tomography. Results were analyzed with 1-way analysis of variance and Tukey's post hoc test (α = 0.05). RESULTS: OVX decreased maxillary and femoral BMD and altered femoral microarchitecture (P < .05). The drugs increased BMD of both types of bones, but only ALD maintained the phenotype similar to the SHAM group. The action of ALD was limited to the femoral trabecular separation (Tb.Sp). OVX and the drugs had no effect on the microarchitecture of the maxilla (P > .05). CONCLUSIONS: ALD and ODN therapy increased BMD in both bones after ovariectomy. ALD was more successful than ODN in preserving the morphology of bone similar to the SHAM group. ALD maintained the phenotype for Tb.Sp in the femur, but ODN did not. In the maxillae, neither ovariectomy nor the 2 antiresorptive drugs had significant effects on microarchitecture.
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Alendronato , Compostos de Bifenilo , Densidade Óssea , Fêmur , Imageamento Tridimensional , Maxila , Microtomografia por Raio-X , Animais , Feminino , Ratos , Alendronato/farmacologia , Compostos de Bifenilo/farmacologia , Densidade Óssea/efeitos dos fármacos , Fêmur/diagnóstico por imagem , Fêmur/efeitos dos fármacos , Maxila/diagnóstico por imagem , Maxila/efeitos dos fármacos , Ovariectomia , Fenótipo , Distribuição Aleatória , Ratos WistarRESUMO
OBJECTIVE: To evaluate the effect of a single-dose local administration of PTH on bone healing in rat calvarial bone defects by means of micro-computed tomography, histological and histomorphometric analysis. DESIGN: Critical-size cranial osteotomy defects were created in 42 male rats. The animals were randomly divided into 3 groups. In the C Group, the bone defect was only filled with a blood clot. In the S Group, it was filled with a collagen sponge and covered with bovine cortical membrane. In the PTH Group, the defect was filled with a collagen sponge soaked with PTH and covered with bovine cortical membrane. The groups were further split in two for euthanasia 15 and 60days post-surgery. Data was statistically analyzed with t-tests for independent samples or the nonparametric Mann-Whitney test when applicable. Intragroup comparisons were analyzed with paired t-tests (p<0.05). RESULTS: Micro-CT analysis results did not demonstrate statistically significant intergroup differences. At 15days post-surgery, the histomorphometric analysis showed that the PTH Group exhibited a significantly higher percentage of bone formation compared with the S Group. At 60days post-surgery, a higher percentage of new bone was observed in the PTH group. CONCLUSION: The results suggest that the local administration of PTH encouraged the bone healing in critical-size calvarial defects in rats.
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Hormônio Paratireóideo/farmacologia , Crânio/efeitos dos fármacos , Crânio/patologia , Cicatrização/efeitos dos fármacos , Microtomografia por Raio-X/métodos , Animais , Regeneração Óssea/efeitos dos fármacos , Bovinos , Colágeno/farmacologia , Masculino , Osteogênese/efeitos dos fármacos , Hormônio Paratireóideo/administração & dosagem , Ratos , Ratos Wistar , Crânio/diagnóstico por imagem , Crânio/cirurgia , Fatores de TempoRESUMO
The aim of the study was to evaluate canal preparation in primary molars with hand files, ProTaper Next and Self-Adjusting File (SAF) by 2D and 3D micro-computed tomography (micro-CT) analysis. Canals of 24 primary molars were prepared with hand files (HF), ProTaper Next (PTN) and SAF (n=8/group). The teeth were scanned before and after root canal preparation and the pre- and postoperative micro-CT images were reconstructed. Changes in 2D (area, perimeter, roundness, minor and major diameter) and 3D [volume, surface area, structure model index (SMI)] morphological parameters, as well as canal transportation and lateral perforations were evaluated (Kruskal-Wallis and ANOVA; a=0.05). SAF presented smaller changes in minor diameter, volume and surface area compared with HF and PTN (p<0.05). PTN presented more circular canals after preparation. 3D analysis revealed greater transportation in HF. PTN and SAF presented more centered canal preparation, especially in curved areas. SAF and HF presented, respectively, the lowest (0.05±0.02 and 0.07±0.04) and highest (0.14±0.11 and 0.29±0.17) apical transportation. There were fewer lateral perforations in SAF (4.2%) and PTN (7.7%) than in HF (47.8%) (p<0.05). In primary molars, mechanical preparation showed better shaping ability than hand files, promoting more centered preparations and lower occurrence of lateral perforations and canal transportation. CLINICAL RELEVANCE: Manual instrumentation is still reported as the main choice in the primary teeth preparation; however, studies have shown limitations in its use. The morphological characteristics of primary teeth and the limited knowledge of shaping procedures in these teeth using mechanical preparation become a challenge for clinical practice and might impair the predictability of endodontic treatment.
Assuntos
Dente Molar , Preparo de Canal Radicular/métodos , Dente Decíduo , Microtomografia por Raio-X/métodos , HumanosRESUMO
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.