RESUMO
AIM: To assess the effect of 90°-oscillatory instrumentation with hand files on several morphological parameters (volume, surface area and uninstrumented surface) in C-shaped root canals after instrumentation using a single-file reciprocation system (Reciproc; VDW, Munich, Germany) and a Self-Adjusting File System (SAF; ReDent Nova, Ra'anana, Israel). METHODOLOGY: Twenty mandibular second molars with C-shaped canals and C1 canal configurations were divided into two groups (n = 10) and instrumented with Reciproc and SAF instruments. A size 30 NiTi hand K-file attached to a 90°-oscillatory motion handpiece was used as final instrumentation in both groups. The specimens were scanned using micro-computed tomography after all procedures. Volume, surface area increase and uninstrumented root canal surface were analysed using CTAn software (Bruker-microCT, Kontich, Belgium). Also, the uninstrumented root canal surface was calculated for each canal third. All values were compared between groups using the Mann-Whitney test and within groups using the Wilcoxon's signed-rank test. RESULTS: Instrumentation with Reciproc significantly increased canal volume compared with instrumentation with SAF. Additionally, the canal volumes were significantly increased after 90°-oscillatory instrumentation (between and within group comparison; (P < 0.05)). Regarding the increase in surface area after all instrumentation protocols, statistical analysis only revealed significant differences in the within groups comparison (P < 0.05). Reciproc and SAF instrumentation yielded an uninstrumented root canal surface of 28% and 34%, respectively, which was not significantly different (P > 0.05). Final oscillatory instrumentation significantly reduced the uninstrumented root canal surface from 28% to 9% (Reciproc) and from 34% to 15% (SAF; P < 0.05). The apical and middle thirds exhibited larger uninstrumented root canal surfaces after the first instrumentation that was significantly reduced after oscillatory instrumentation (P < 0.05). CONCLUSIONS: The Reciproc and SAF system were associated with similar morphological parameters after instrumentation of mandibular second molars with C-shaped canals except for a higher canal volume increase in the Reciproc group compared to the SAF. Furthermore, the final use of 90°-oscillatory instrumentation using NiTi hand files significantly decreased the uninstrumented canal walls that remained after Reciproc and SAF instrumentation.
Assuntos
Tratamento do Canal Radicular/instrumentação , Cavidade Pulpar/diagnóstico por imagem , Cavidade Pulpar/cirurgia , Humanos , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Níquel , Tratamento do Canal Radicular/métodos , Titânio , Microtomografia por Raio-XRESUMO
AIM: To describe morphometric aspects of the internal anatomy of C-shaped mandibular premolars from a Brazilian subpopulation using micro-CT analysis. METHODOLOGY: First mandibular premolars with radicular grooves (n = 123) were scanned using a micro-computed tomography system. After cross-section analysis, 83 specimens were identified with a C-shaped canal and selected for micro-CT analysis. Number and location of canals according to Vertucci's classification, distances between anatomic landmarks, occurrence of apical deltas, furcation canals, prevalence of C-shaped cross-sections at five levels as well as 2-dimensional analysis (Area, perimeter, roundness, aspect ratio, major and minor diameters) were performed for the more prevalent anatomical features. Data were compared statistically using Kruskal-Wallis tests (α = 0.05). RESULTS: The more prevalent anatomical types according to Vertucci's classification were Type I (13%), III (8%), V (37%) and VII (2%). Mean distances from the furcation to the cemento-enamel junction were in the range of 5.36-5.65 mm. Apical deltas and furcation canals were present in 36 (43%) and 27 (33%) specimens, respectively. C-shaped cross-sections were more prevalent at the middle (56%) and apical middle levels (81%). Overall, significant differences were found in the 2-dimensional analyses between single canals at the apical third and buccal and lingual canals of Vertucci's V classification (P < 0.05). CONCLUSIONS: In this Brazilian subpopulation, C-shaped canal configuration of the root canal system was found in 67% of extracted first mandibular premolars with radicular grooves. Vertucci's types I and V were the most prevalent anatomical variations. C-shaped cross-sections were more prevalent in the middle third, and the presence of apical deltas was the most common feature in the apical third.
Assuntos
Dente Pré-Molar/anatomia & histologia , Dente Pré-Molar/diagnóstico por imagem , Raiz Dentária/anatomia & histologia , Raiz Dentária/diagnóstico por imagem , Microtomografia por Raio-X , Brasil , Humanos , Técnicas In Vitro , Mandíbula/anatomia & histologia , Mandíbula/diagnóstico por imagemRESUMO
AIM: To evaluate the volume of remaining filling material in the mesial root canals of mandibular molars after root canal retreatment with different procedures performed sequentially. METHODOLOGY: The mesial root canals of 12 human first mandibular molars were instrumented using the BioRace system until a size 25, .06 taper instrument. The mesial roots were filled with gutta-percha and AH-Plus using a vertical compaction technique. The specimens were scanned using microcomputed tomography with a voxel size of 16.8 µm before and after the retreatment procedures. To remove the filling material, the root canals were enlarged until the size 40, .04 taper instrument. The second step was to irrigate the root canals with xylene in the attempt to clean the root canals with paper points. In the third step, the passive ultrasonic irrigation technique (PUI) was performed using 2.5% sodium hypochlorite. The initial and residual filling material volume (mm(3) ) after each step was evaluated from the 0.5 to 6.5 mm level. The obtained data were expressed in terms of percentage of residual filling material. Statistical analysis was performed using the Friedman test (P < 0.05). RESULTS: All specimens had residual filling materials after all retreatment procedures. Passive ultrasonic irrigation enhanced the elimination of residual filling material in comparison with the mechanical stage at the 0.5-2.5 mm and 4.5-6.5 mm levels (P < 0.05). No significant difference was found between xylene and PUI methods. CONCLUSIONS: Filling materials were not completely removed by any of the retreatment procedures. The use of xylene and PUI after mechanical instrumentation enhanced removal of materials during endodontic retreatment of anatomically complex teeth.
Assuntos
Materiais Restauradores do Canal Radicular , Irrigação Terapêutica , Dente/diagnóstico por imagem , Xilenos/metabolismo , Humanos , Ultrassom , UltrassonografiaRESUMO
AIM: To evaluate the radiopacity, setting time, pH level, calcium ion release and solubility of white mineral trioxide aggregate (MTA; Angelus, Londrina, Pr, Brazil) with different powder-to-water ratios. METHODOLOGY: Three MTA groups were prepared using 4 : 1, 3 : 1 and 2 : 1 powder-to-water ratios. For the radiopacity analysis, the 10 × 1 mm specimens were arranged on occlusal films with a cylinder of dentine and an aluminium stepwedge. The digitized radiographs were evaluated with Digora 1.51 software to determine the radiographic density. The setting time test was performed according to the American Society for Testing and Materials 266/08 standard specifications, but the specimens were made according to International Organization for Standardization 6876:2001. Thirty acrylic teeth with root-end filling material were immersed in ultrapure water for measurement of pH level and calcium ion release (atomic absorption spectrophotometer) at 3, 24, 72 and 168 h. In the solubility test, the root-end fillings of 30 acrylic teeth were scanned twice by a Micro-CT, before and after immersion in ultrapure water for 168 h. Digital data were reconstructed, and the volume (mm(3) ) of the samples was obtained using CTan software (CTan v1.11.10.0, SkyScan). The data were statistically analysed by the anova, Tukey, Kruskal-Wallis and Dunn's tests. RESULTS: The radiopacity was higher (P < 0.05) when the 4 : 1 proportion was utilized. The setting time was longer, and the pH level and calcium ion release were higher (P < 0.05) with a greater volume of water. The group with more water (2 : 1) had significantly (P < 0.05) more material volume loss (6.46%) compared with the other groups. CONCLUSIONS: The ratio of powder/water significantly interfered with the physical and chemical properties of white MTA Angelus.
Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Cálcio/química , Óxidos/química , Pós , Silicatos/química , Água , Microtomografia por Raio-X/métodos , Combinação de Medicamentos , Concentração de Íons de Hidrogênio , SolubilidadeRESUMO
AIM: To analyse several physicochemical properties of AH Plus (Dentsply DeTrey, Konstanz, Germany), including setting time, flow, radiopacity and the degree of conversion (DC); and to correlate the results with the source of the material: from the beginning, middle or end of the tubes in which they were supplied. METHODOLOGY: Three experimental groups were established for each property investigated. Group 1 corresponded to material taken from the beginning of tubes A and B; Group 2 corresponded to material taken from the middle of each tube; and group 3 corresponded to that from the end of each tube. The setting time, flow and radiopacity were studied according to American National Standards Institute/American Dental Association (ANSI/ADA) Specification 57. DC was determined from infrared spectra, which were recorded at 1-h intervals for the first 6 h; then, at 2-h intervals for the next 14 h; then, at 24 and 30 h. Data were analysed statistically by analysis of variance (anova), Tukey-Kramer, Kruskal-Wallis and Dunn tests, with a significance level of 5%. RESULTS: Group 1 had a significantly longer setting time (2303 ± 1058 min) (P < 0.05). Group 3 had the lowest flowability (30.0 ± 0.7 mm) and the highest radiopacity (14.85 ± 1.8 mm Al) (P < 0.05). No differences were found for the DC test (P > 0.05). CONCLUSION: The results suggest that segregation occurs between the organic and inorganic components of AH Plus sealer, thereby changing the setting time, flow and radiopacity.
Assuntos
Resinas Epóxi/química , Cimentos de Resina/química , Materiais Restauradores do Canal Radicular/química , Análise de Variância , Fenômenos Químicos , Meios de Contraste , Resinas Epóxi/normas , Hidrodinâmica , Teste de Materiais , Polimerização , Cimentos de Resina/normas , Materiais Restauradores do Canal Radicular/normasRESUMO
AIM: To evaluate the residual biovolume of live bacterial cells, the mean biofilm thickness and the substratum coverage found in mixed biofilms treated with different endodontic irrigant solutions. METHODOLOGY: Twenty-five bovine dentine specimens were infected intraorally using a removable orthodontic device. Five samples were used for each irrigant solution: 2% chlorhexidine, 1% sodium hypochlorite (NaOCl), 10% citric acid, 17% EDTA and distilled water. The solutions were used for 5 min. The samples were stained using the Live/Dead technique and evaluated using a confocal microscope. Differences in the amount of total biovolume (µm(3)), number of surviving cells (µm(3)), mean biofilm thickness (µm) and substratum coverage (%) of the treated biofilms were determined using nonparametric statistical tests (P < 0.05). RESULTS: Similar values of biovolume total, biovolume of live subpopulations and substratum coverage were found in 2% chlorhexidine, 10% citric acid, 17% EDTA and distilled water-treated biofilms (P > 0.05). The lower values of the studied parameters were found in 1% NaOCl-treated dentine (P < 0.05) with the exception of the mean biofilm height criteria that did not reveal significant differences amongst the irrigant solutions (P > 0.05). CONCLUSIONS: One per cent sodium hypochlorite was the only irrigant that had a significant effect on biofilm viability and architecture.
Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Dentina/microbiologia , Irrigantes do Canal Radicular/farmacologia , Animais , Anti-Infecciosos Locais/farmacologia , Bovinos , Quelantes/farmacologia , Clorexidina/farmacologia , Ácido Cítrico/farmacologia , Corantes , Ácido Edético/farmacologia , Corantes Fluorescentes , Humanos , Imageamento Tridimensional/métodos , Viabilidade Microbiana/efeitos dos fármacos , Microscopia Confocal , Compostos Orgânicos , Contenções Ortodônticas , Propídio , Hipoclorito de Sódio/farmacologia , ÁguaRESUMO
AIM: To compare the percentage of gutta-percha, sealer and voids and the influence of isthmuses in mesial root canals of mandibular molars filled with different techniques. METHODOLOGY: Canals in 60 mesial roots of mandibular first molars were prepared with ProTaper instruments to size F2 (size 25, 0.08 taper) and filled using a single-cone, lateral compaction, System B or Thermafil techniques. An epoxy resin sealer was labelled with Rhodamine-B dye to allow analysis under a confocal microscope. The percentage of gutta-percha, sealer and area of voids was calculated at 2, 4 and 6 mm from the apex, using Image Tool 3.0 software. Statistical analysis was performed using nonparametric Kruskal-Wallis and Dunn tests (P < 0.05). The influence of isthmuses on the presence or absence of voids was evaluated using the Fisher test. RESULTS: At the 2 mm level, the percentage of gutta-percha, sealer and voids was similar amongst the System B, lateral compaction and single-cone techniques. The single-cone technique revealed significantly less gutta-percha, more sealer and voids in comparison with the Thermafil technique at the 2 and 4 mm level (P < 0.05). The analysis of all sections (2, 4 and 6 mm) revealed that more gutta-percha and less sealer and voids were found in root canals filled with Thermafil and System B techniques (P < 0.05). The Fisher test revealed that the presence of isthmuses increased the occurrence of voids in the lateral compaction group only (P < 0.05). CONCLUSION: Gutta-percha, sealer filled area and voids were dependent on the canal-filling technique. The presence of isthmuses may influence the quality of root filling.