RESUMO
AIM: To evaluate in a laboratory setting the performance of two reciprocating glide path systems, WaveOne Gold Glider (WO) and R-Pilot (RP), to create a glide path in mesial root canals of mandibular molars and to assess the torsional resistance of instruments after performing the glide path. METHODOLOGY: A total of 60 mesial root canals of extracted human mandibular molars were divided into two groups (n = 30) according to the glide path system to be used. The data from the volume of each canal, acquired by microcomputed tomography (micro-CT), were validated statistically for the anatomical pairing of the groups. Preparation time, frequency in gaining apical patency, plastic deformation rate of instruments, and canal transportation and centring ability were recorded and compared statistically. The torsional fatigue of the instruments after use was also evaluated. Data were analysed using Fisher's exact test and Mann-Whitney U-test with a 5% significance level. RESULTS: No significant differences were found between groups regarding the time required to perform the glide path, the frequency distributions of the canals classified as patent and the instruments with plastic deformation after use (P > 0.05). No significant differences were found between groups regarding the degree of canal transportation and centring ability at the cervical, middle and apical thirds (P > 0.05). The RP groups had significantly greater maximum torsional strength values compared with the WO groups (P < 0.05). The used WO group had greater angular deflection to fracture when compared to the new WO group (P < 0.05). A significant difference was also found in the percentage of loss of angular deflection in a comparison of the WO group with the RP group (P < 0.05). CONCLUSIONS: The WO and RP instruments performed the same in terms of preparation time, plastic deformation, gaining apical patency, degree of canal transportation and centring ability. The RP instruments had greater torsional strength, less angular deflection and lower percentage of loss in angular deflection than the WO. The used WO group had the greatest angular deflection values.
Assuntos
Cavidade Pulpar , Laboratórios , Instrumentos Odontológicos , Cavidade Pulpar/diagnóstico por imagem , Desenho de Equipamento , Humanos , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Preparo de Canal Radicular , Estatísticas não Paramétricas , Titânio , Microtomografia por Raio-XRESUMO
AIM: To evaluate the influence of larger apical canal enlargement in curved canals using reciprocating systems subjected to various heat treatments. METHODOLOGY: Ninety mandibular premolars with root curvatures ranging from 20° to 30° were selected and scanned by microcomputed tomography (micro-CT) before and after root canal preparation with reciprocating systems (n = 30): Reciproc Blue (RB size 25, .08 taper and size 40, .06 taper; VDW, Munich, Germany), WaveOne Gold (WOG size 25, .07 taper and size 35, .06 taper; Dentsply Sirona, Ballaigues, Switzerland) and ProDesign R (PDR size 25, .06 taper and size 35, .05 taper; Easy Dental Equipment, Belo Horizonte, Brazil). Canal transportation, untouched areas, and apical and total root canal volumes were measured. Statistical analysis was performed with the nonparametric Kruskal-Wallis and Dunn's tests and a significance level set at 5%. RESULTS: The between-group comparison revealed no significant difference in untouched areas, canal transportation, and apical root canal volume among the groups (P > 0.05). However, WOG size 35, .06 taper was associated with a significant increase in the percentage of total canal volume in comparison to the PDR size 35, .05 taper (P < 0.05). The within-group comparison revealed a significant decrease in untouched areas, increase in apical and total root canal volume for all groups when using a larger instrument (P < 0.05). There was no significant difference in transportation among the groups and when a larger apical preparation was created (P > 0.05). CONCLUSIONS: Larger apical enlargement of curved canals was associated with a decrease in untouched areas, an increase in root canal volume and maintenance of canal trajectory. In addition, all systems were safe and provided similar root canal shapes.
Assuntos
Instrumentos Odontológicos , Temperatura Alta , Brasil , Cavidade Pulpar , Desenho de Equipamento , Alemanha , Preparo de Canal Radicular , Microtomografia por Raio-XRESUMO
AIM: To determine whether a relationship exists between the apical shape of roots and root canal system complexity by performing a micro-computed tomography analysis. METHODOLOGY: One hundred extracted permanent maxillary first molars were scanned using a micro-computed tomography device at 19.6 µm voxel size. Two groups of mesiobuccal roots were formed according to the root aspect ratio value in the apical 3-mm cross-sectional level ('<2 and ≥ 2.00'). Data were recorded regarding the number and presence of accessory canals and their location, isthmus, presence of the mesiobuccal canal and dentine thickness. Depending on the analysed variable, Mann-Whitney U test and Z-test for proportions were used to compare groups. The significant level was set at 5%. RESULTS: Mesiobuccal roots with an aspect ratio ≥ 2.00 at the apical 3-mm cross-sectional level had higher percentages of accessory canals, apical foramina and MB2 root canals in the apical 3 mm. The vertical average distance from the accessory foramina and origin from the anatomic apex was 1.40 and 2.19 mm, respectively. Overall, 21.8% of the accessory canals had their origin coronal to a 3-mm root resection line. There was no difference between the groups regarding dentine thickness. CONCLUSION: The shape of the apical 3 mm of maxillary first molar mesiobuccal roots was a predictive factor for the presence of complex root canal systems. Roots with a lower aspect ratio had less complex apical anatomy.
Assuntos
Cavidade Pulpar , Raiz Dentária , Estudos Transversais , Dente Molar , Prevalência , Microtomografia por Raio-XRESUMO
AIM: To evaluate dentine thickness from both distal ('danger zone') and mesial ('safety zone') aspects of the MB1 and MB2 canals of maxillary first molars at the furcation level using micro-CT imaging. METHODOLOGY: One hundred maxillary first molars with two canals in the MB root were selected from a Brazilian subpopulation and scanned at a resolution of 19.6 µm in a micro-CT device. From each specimen, two axial cross-sectioned images were selected at 2 and 3 mm apical to the furcation level of the MB root and evaluated for the smallest dentinal thickness. Measurements were made from the outer perimeter of the MB1 and MB2 canals towards the external root surface from both distal (danger zone) and mesial (safety zone) aspects of the root. The influence of an isthmus was also considered in the analysis, and samples were classified according to the presence or absence of an isthmus in the axial sections. Non-parametric Wilcoxon signed-rank tests were used to compare dentinal thickness between MB1 and MB2 canals with a significant level set at 5%. Colour-coded 3D models of dentine thickness throughout the MB root were created and evaluated qualitatively. RESULTS: At both levels, median dentine thickness of the MB2 canal was significantly lower in both distal and mesial aspects of the root in comparison with the MB1 canal (P < 0.01). The presence of an isthmus was not a variable that influenced dentinal thickness. Colour-coded models indicated that dentine thickness was dependent on the cross-sectional shape of the MB root. At least 50% of the sample had <1 mm of dentine thickness at the danger zone of the MB2 canal. CONCLUSIONS: Danger zones in the MB roots of maxillary first molars were not symmetrical. MB2 canals had less dentine thickness on both aspects of the root compared to the MB1 canal.
Assuntos
Cavidade Pulpar , Maxila , Brasil , Estudos Transversais , Dente Molar , Raiz Dentária , Microtomografia por Raio-XRESUMO
AIM: To investigate the effects of combinations of several irrigants on the roughness and wettability of dentine, adhesion of Enterococcus faecalis and Candida albicans and adsorption of chlorhexidine (CHX) to the dentine. METHODOLOGY: Bovine dentine samples were prepared and their surface roughness standardized. The samples were distributed in groups (n = 10) and subjected to one of the following irrigation protocols: G1 - saline solution; G2 - sodium hypochlorite (NaOCl); G3 - NaOCl + ethylenediaminetetraacetic acid (EDTA); G4 - NaOCl + peracetic acid (PAA); G5 - NaOCl + 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP); G6 - NaOCl + EDTA + CHX; G7 - NaOCl + PAA + CHX; G8 - NaOCl + HEDP + CHX; and G9 - mixture of NaOCl + HEDP. After treatments, roughness and wettability were measured. In order to evaluate the adhesion of microorganisms to dentine, new dentine samples were prepared and after 2 h of contact with the microorganisms, were analysed using a confocal laser scanning microscope and the number of microorganisms adhering to the surfaces were determined. Absorption spectra were collected by attenuated total reflectance of Fourier-transform infrared spectroscopy before and after immersion of other dentine samples in each solution of G6, G7 and G8 and in a solution of 2% CHX at various time intervals. The areas of the band associated with CHX with the peak at 1492 cm-1 were calculated between 1479 and 1500 cm-1 of the spectral range. The data obtained in all experiments were subjected to one-way ANOVA (α < 0.05). The values of the CHX band were also subjected to one-way repeated measures ANOVA (α < 0.05). RESULTS: Saline solution, NaOCl, HEDP and CHX did not alter the roughness of the dentine (P > 0.05), whilst EDTA and PAA did (P < 0.05). Dentine surface wettability increased after the use of all irrigants compared to saline solution (P < 0.05), with HEDP causing the greatest increases (P < 0.05). The adhesion of E. faecalis was favoured on surfaces treated with only saline solution and NaOCl, and on samples that had decalcifying agents as the final irrigant (P < 0.05). The adhesion of C. albicans was highest on surfaces treated with only saline solution and on surfaces that had NaOCl used as the last irrigant (P < 0.05). The use of CHX as a final irrigant reduced the adhesion of both microorganisms. The roughness and wettability did not influence the adhesion of the microorganisms tested. The adsorption of CHX to the dentine was significant after 1 min of immersion of the mineralized samples in the irrigant (P < 0.05), and the use of chelating agents prior to CHX potentiated this adsorption. CONCLUSIONS: The irrigation solutions had a variable effect on the properties of dentine, on the adhesion of E. faecalis and C. albicans and the adsorption of CHX to the dentine surface.
Assuntos
Aderência Bacteriana/efeitos dos fármacos , Clorexidina/farmacologia , Dentina/efeitos dos fármacos , Dentina/microbiologia , Dentina/patologia , Irrigantes do Canal Radicular/farmacologia , Adsorção/efeitos dos fármacos , Animais , Candida albicans/efeitos dos fármacos , Bovinos , Quelantes/farmacologia , Ácido Edético/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Ácido Etidrônico/farmacologia , Teste de Materiais , Ácido Peracético/farmacologia , Hipoclorito de Sódio/farmacologia , Propriedades de Superfície/efeitos dos fármacosRESUMO
AIM: To evaluate apical transportation and centring ability during root canal preparation in mesial root canals of mandibular molars associated with ProTaper Gold (PTG), ProDesign S (PDS), Hyflex CM (HCM), Hyflex EDM and ProDesign Logic (PDL). METHODOLOGY: Sixty mandibular first molars with two separate canals in the mesial root were selected after root anatomy pairing by microcomputed tomography (microCT). The teeth were randomly divided into five groups (n = 24); the root canal volume was calculated to ensure sample homogeneity. All the root canals were prepared up to size 25 in accordance with the instructions of each rotary system manufacturer. After root canal preparation, the teeth were scanned by microCT to analyse apical transportation, root canal centralization and the pre- and post-preparation root canal volume at the apical and cervical levels. Kruskal-Wallis and Dunn tests were used for comparisons amongst groups for transportation values. For volume changes, the parametric ANOVA and Tukey's tests were used RESULTS: There were no significant differences in apical transportation amongst the rotary systems (P > 0.05). All the systems created apical transportation; values ranging from 0.031 mm (PDL) to 0.072 mm (PTG), and enlargements between 39% (HCM) and 91.1% (PDS) were observed. In relative to cervical transportation, significant differences were observed amongst the systems (P < 0.05). Mean transportation values between 0.07 mm (HCM) and 0.172 mm (PTG) were found, with enlargements between 35.4% (HCM) and 51.5% (PDS). CONCLUSION: All the thermally treated systems resulted in similar apical transportation. In the cervical region, the Hyflex CM and Prodesign Logic systems were associated with more centred preparations.
Assuntos
Ligas Dentárias/química , Instrumentos Odontológicos , Níquel/química , Preparo de Canal Radicular/instrumentação , Titânio/química , Cavidade Pulpar/diagnóstico por imagem , Desenho de Equipamento , Temperatura Alta , Humanos , Técnicas In Vitro , Teste de Materiais , Dente Molar , Propriedades de Superfície , Microtomografia por Raio-XRESUMO
AIM: To evaluate the torsional properties of pathfinding nickel-titanium (NiTi) rotary instruments manufactured from several NiTi alloys, ProGlider (M-wire), Hyflex GPF (conventional NiTi Wire and controlled memory wire), Logic (conventional NiTi wire and controlled memory wire) and Mtwo (conventional NiTi wire). METHODOLOGY: A total of 56 NiTi instruments from Glidepath rotary systems (n = 8) were used: Logic (size 25, .01 taper), Logic CM (size 25, .01 taper), ProGlider (size 16, .02 taper), Hyflex GPF (size 15, .01 taper), Hyflex GPF CM (size 15, .02 taper; size 20, .02 taper) and Mtwo (size 10, .04 taper). The torsion tests were performed based on ISO 3630-1 (1992). Three millimetres of each instrument tip was clamped to a small load cell by a lever arm linked to the torsion axis. Data were analysed using a one-way analysis of variance (anova) and Tukey test with a significance level at a = 5%. RESULTS: The Logic size 25, .01 taper had significantly higher torsional strength values (P < 0.05). The ProGlider was significantly different when compared with Hyflex GPF size 15, .01 taper and size 15, .02 taper (P < 0.05). The Logic CM size 25, .01 taper had significantly higher torsional strength than Hyflex GPF size 15, .01 taper and size 15, .02 taper (P < 0.05). No difference was found amongst Mtwo size 10, .04 taper and Hyflex GPF groups (size 15, .01 taper; size 15, .02 taper; size 20, .02 taper). In relation to the angle of rotation, Logic CM size 25, .01 taper and Hyflex GPF size 15, .01 taper had the highest angle values (P < 0.05). The ProGlider had the lowest angle values in comparison with all the groups (P < 0.05) followed by Mtwo size 10, .04 taper. The Logic size 25, .01 taper had significantly higher angle of rotation values than ProGlider and Mtwo size 10, .04 taper (P < 0.05). CONCLUSION: The Logic size 25, .01 taper instrument made of conventional NiTi alloy had the highest torsional strength of all instruments tested. In addition, the ProGlider instrument manufactured from M-Wire alloy had the lowest angle of rotation to fracture in comparison with the other instruments.
Assuntos
Ligas Dentárias/química , Instrumentos Odontológicos , Níquel/química , Titânio/química , Torção Mecânica , Desenho de Equipamento , Falha de Equipamento , Teste de Materiais , Microscopia Eletrônica de Varredura , Tratamento do Canal Radicular/instrumentação , Estresse MecânicoRESUMO
AIM: To investigate the effects of several decalcifying agents alone and in combination with sodium hypochlorite (NaOCl) on the organic and inorganic components of dentine using attenuated total reflectance in Fourier transform infrared spectroscopy (ATR-FTIR). METHODOLOGY: Dentine slices from bovine teeth were submitted to (n = 5) the following: 0.9% saline, 9% and 18% etidronic acid (HEDP), 5% and 10% tetrasodium EDTA (EDTANa4 ), 17% trisodium EDTA (EDTAHNa3 ), and 0.5% and 2.0% peracetic acid (PAA) for 0.5-10 min; and to the combinations: G1 - mixture 5% NaOCl + 18% HEDP (5 and 10 min); G2 - mixture 5% NaOCl + 10% EDTANa4 (5 and 10 min); G2 - 2.5% NaOCl (5 min) + 17% EDTAHNa3 (1 min); G3 - 2.5% NaOCl (5 min) + 0.5% PAA (1 min); G4 - 2.5% NaOCl (5 min) + 9% HEDP (5 min). Specimens of G2, G3 and G4 received final flushes with 2.5% NaOCl for 0.5-10 min. Amide III/phosphate and carbonate/phosphate ratios of the spectra collected from the dentine specimens before and after immersion in the solutions were determined. Data were submitted to one-way repeated measures and one-way anova. RESULTS: For the same decalcifying agent, the higher the concentration and immersion time the greater the removal of phosphate, exposure of collagen matrix and consequently the increases in amide III/phosphate ratio. However, significant differences were found only between the two concentrations of PAA (P < 0.05). PAA caused greater increases in this ratio, followed by EDTAHNa3 , EDTANa4 and HEDP, and this order was retained in the combinations with NaOCl. This ratio was significantly reduced in G1 (P < 0.05) and not altered in G2 (P > 0.05). Due to collagen degradation, the amide III/phosphate ratio reduced significantly after the use of NaOCl in G3, G4 and G5 (P < 0.05). NaOCl required approximately 0.5 s to deproteinate the collagen matrix exposed after phosphate removal by EDTAHNa3 and PAA. The carbonate of dentine was removed more rapidly than phosphate by all decalcifying agents alone and in G3, G4 and G5. In the combinations with NaOCl, the last irrigant used defined the dentine amide III/phosphate and carbonate/phosphate ratios. CONCLUSIONS: HEDP and EDTANa4 caused minor whilst EDTAHNa3 and PAA caused greater demineralization of dentine; both effects were time and concentration dependent. NaOCl degraded the dentine organic matrix more rapidly when it was exposed. Combinations of NaOCl and decalcifying agents can be used to create dentine surfaces with varying compositions for interaction with endodontic sealers.
Assuntos
Dentina/química , Irrigantes do Canal Radicular/farmacologia , Hipoclorito de Sódio/farmacologia , Animais , Bovinos , Dentina/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Desmineralização do Dente/induzido quimicamenteRESUMO
AIM: To evaluate the internal and external morphologies of fused-rooted maxillary second molars by means of micro-computed tomography (micro-CT) analysis. METHODOLOGY: A total of 100 fused-rooted maxillary second molars from a Brazilian subpopulation were divided into six groups according to the root morphology. The samples were scanned at a resolution of 19.6 µm and evaluated with regard to the external morphology of the roots, the root canal configuration, the percentage frequency of C-shaped canals and isthmuses, as well as the morphology of the root canal system at 1, 2 and 3 mm from the anatomical apex of the fused roots. RESULTS: The most prevalent root canal fusions were type 1, mesiobuccal root fused with distobuccal root (32%), followed by type 3, DB root fused with P root (27%), and type 4, MB root fused with DB root, and P root fused with MB or DB roots (21%). The prevalence of C-shaped root canal systems were 22%. Depending on the type of root fusion, the percentage frequency of isthmuses in the apical level varied from 9.3% to 42.8%, whilst the presence of apical deltas ranged from 18.5% to 57.1% of teeth. CONCLUSIONS: The root canal system of maxillary second molars with fused roots may have a high incidence of merging canals, isthmuses, apical deltas and C-shaped configurations.
Assuntos
Dente Molar/anormalidades , Raiz Dentária/anormalidades , Humanos , Imageamento Tridimensional , Maxila , Dente Molar/anatomia & histologia , Dente Molar/diagnóstico por imagem , Raiz Dentária/anatomia & histologia , Raiz Dentária/diagnóstico por imagem , Microtomografia por Raio-XRESUMO
AIMS: To compare the accuracy of the clearing technique and cone beam computed tomography (CBCT) in the assessment of root canal configurations using micro-computed tomography (micro-CT) imaging system as the reference standard. METHODOLOGY: Thirty-two mesial roots of mandibular first molars, selected on the basis of micro-CT scans (voxel size: 19.6 µm) and presenting several canal configurations, were evaluated using 2 CBCT scanners (voxels sizes: 120 µm and 150 µm) followed by the clearing technique. Two examiners analysed the data from each method and classified the anatomical configuration of the mesial canal according to Vertucci's system. Data were compared using Fisher's exact and chi-square tests. Reliability for each assessment was verified by the kappa test, and significance level was set at 5%. RESULTS: Kappa value indicated a high level of agreement between the examiners. Detection of type I configurations was significantly lower in cleared teeth (P < 0.05), whilst type II root canals were detected in all specimens by both tests (P > 0.05). In mesial roots with variable anatomical configurations, CBCT and the clearing method were significantly less accurate than the reference standard (P < 0.05). CONCLUSION: Within the tooth population studied, accuracy of identifying mesial root canal configuration was influenced greatly by the evaluation method and the type of anatomy. Detection of type I configurations in cleared teeth was significantly lower, whilst type II configurations were detected in all specimens by both methods. In mesial roots with variable anatomical configurations, neither CBCT nor clearing methods were accurate for detecting the actual root canal anatomy.