RESUMEN
AIM: To investigate the reliability of using bovine teeth as an alternative to human teeth in an intra-tooth push-out model by comparing the bond strength of three root canal sealers in both tooth substrates. METHODOLOGY: From human and bovine incisors (12 per group), one 1-mm disc was obtained from each root. On each disc, three standard 0.8-mm-diameter holes were drilled through the dentine. After irrigation, the holes were filled with one of three root canal sealers: AH Plus, MTA Fillapex or Total Fill BC Sealer. Tooth slices were kept in contact with sterile gauze moistened in PBS solution (pH = 7.2) for 7 days at 37 °C, and finally, a push-out load was applied until sealer dislocation. The bonded interface area was calculated to obtain data in MPa. The push-out data for each sealer and the overall push-out data for human and bovine teeth were compared (Mann-Whitney U). Kruskal-Wallis was used to study the sealers behaviour at each of the dental substrates. Multiple comparisons were performed using Mann-Whitney U after Bonferroni correction (P < 0.05). RESULTS: Dentine substrate did not influence the push-out of either individual sealers or overall sealers tested (Mann-Whitney U, P > 0.05). In both human and bovine samples, AH Plus performed better than BC Sealer and MTA Fillapex, whilst BC Sealer also provided a superior push-out compared to MTA Fillapex (Mann-Whitney U, P < 0.05). CONCLUSION: When using an intra-tooth model, bovine teeth did not significantly influence the bond strength of sealers.
Asunto(s)
Recubrimiento Dental Adhesivo , Materiales de Obturación del Conducto Radicular , Animales , Bovinos , Análisis del Estrés Dental , Dentina , Resinas Epoxi , Humanos , Reproducibilidad de los ResultadosRESUMEN
AIM: To evaluate the effect of 17% ethylenediaminetetraacetic acid (EDTA), 2.25% peracetic acid (PA) or 10% citric acid (CA) on the push-out bond strength of calcium silicate-based endodontic sealers [MTA Fillapex (Angelus, Londrina, Brazil) and Total Fill BC Sealer (FKG, La Chaux-de-Fonds, Switzerland)] to root dentine after different periods of immersion in phosphate-buffered saline (PBS). AH Plus (Dentsply DeTrey, Konstaz, Germany) was used as a reference material for comparison. METHODOLOGY: Thirty human maxillary incisors were selected and three 1-mm discs were obtained from the middle third of each root. On the axial surface of each disc, three 0.8-mm-diameter holes were drilled through the dentine. After standardized irrigation, each dentine disc from the same root was treated for smear-layer removal with one of the three tested chelating solutions: EDTA, PA or CA. After that, the holes were dried with paper points and filled with one of the three test root canal sealers. The filled dental slices were further immersed in PBS solution (pH 7.2) for 7 days (T1) or 30 days (T2) at 37 °C, before the push-out assay. Friedman, Kruskal-Wallis and Mann-Whitney tests were used respectively to estimate the impact of the independent variables (solutions, sealers and period of PBS immersion) on the push-out bond strength. The level for significance was set at α = 5% and data were further subjected to a Bonferroni correction. RESULTS: Solutions and periods of immersion did not significantly influence the displacement resistance (P = 0.285, and P = 0.104, respectively) of sealers to root dentine. On the other hand, the type of sealer significantly affected the push-out bond strength (P = 0.000). AH Plus was associated with greater resistance to dislodgment compared with Total Fill BC Sealer and MTA Fillapex (P = 0.000). MTA Fillapex resulted in the lowest push-out bond strength (P = 0.000). CONCLUSION: The use of different chelating agents did not influence the push-out bond strength of endodontic sealers. Calcium silicate-based sealers had lower push-out bond strength values compared with a conventional epoxy resin-based sealer (AH Plus).
Asunto(s)
Compuestos de Calcio/uso terapéutico , Recubrimiento Dental Adhesivo/métodos , Selladores de Fosas y Fisuras/química , Materiales de Obturación del Conducto Radicular/química , Silicatos/uso terapéutico , Capa de Barro Dentinario/terapia , Análisis del Estrés Dental , Humanos , Selladores de Fosas y Fisuras/uso terapéutico , Materiales de Obturación del Conducto Radicular/uso terapéuticoRESUMEN
AIM: To evaluate the cytotoxic effects of Biodentine, using a three-dimensional (3D) cell culture associated with an in situ root-end filling experimental model. White mineral trioxide aggregate (MTA) and zinc oxide cement were used as reference for comparison. IL-1α and TNF-α cytokine production were also evaluated. METHODOLOGY: The root canals of 24 human maxillary incisor teeth were prepared using a single-file reciprocating technique. After root filling, a 3-mm root-end resection was performed and 3 mm of gutta-percha was removed from the canal. The teeth were randomly distributed to receive one of the following root-end filling materials: Biodentine, white MTA or zinc oxide cement (positive control group). In the negative control group, the root canal was not retro-filled. The cytocompatibility of the materials was evaluated using the methyl-thiazol-diphenyl-tetrazolium (MTT) assay in an in situ root-end filling experimental model. Balb/c 3T3 fibroblasts, cultured in rat tail collagen type I 3D scaffold, were exposed to the root apex for 24 h, and cell viability was measured by means of reduction MTT salt. IL-1α and TNF-α production were analysed using enzyme-linked immunosorbent assay. One-way analysis of variance was performed and, when the F-ratios were significant, data were compared by Duncan's multiple-range test. The alpha-type error was set at 0.05. RESULTS: Biodentine and MTA groups had similar cell activity to the negative control group (P > 0.05), indicating low cytotoxicity for both materials. The stronger cytotoxicity effect was identified on the zinc oxide cement (P < 0.05). Zinc oxide cement caused a significant up-regulation in IL-1α and TNF-α (P < 0.05). No significant differences amongst MTA, Biodentine and the negative control group were observed for TNF-α (P > 0.05); however, both MTA and Biodentine were associated with overproduction of IL-1α when compared to the control group (P < 0.05). CONCLUSIONS: Biodentine and MTA had similar cytocompatibility in a 3D cell culture model associated with an in situ root-end filling model. The methodology could be used as an alternative to assess the cytocompatibility of endodontic cements because it is more closely related to the in vivo situation.
Asunto(s)
Compuestos de Calcio/farmacología , Materiales de Obturación del Conducto Radicular/farmacología , Silicatos/farmacología , Células 3T3 , Compuestos de Aluminio/efectos adversos , Compuestos de Aluminio/farmacología , Animales , Materiales Biocompatibles/efectos adversos , Materiales Biocompatibles/farmacología , Compuestos de Calcio/efectos adversos , Células Cultivadas , Citocinas/metabolismo , Combinación de Medicamentos , Humanos , Ratones , Óxidos/efectos adversos , Óxidos/farmacología , Materiales de Obturación del Conducto Radicular/efectos adversos , Silicatos/efectos adversos , Óxido de Zinc/efectos adversos , Óxido de Zinc/farmacologíaRESUMEN
AIM: To evaluate the amount of apically extruded debris produced by ProTaper Universal (PTU), ProTaper Next (PTN), WaveOne (WO) and Reciproc (R) systems after large apical preparations. METHODOLOGY: Sixty mandibular premolars with a single canal were selected and randomly assigned into 4 groups (n = 15) according to the system used for root canal preparation: PTU, PTN, WO and R groups. Canal preparations were performed up to size 40 in each group. Distilled water was used as an irrigant, and the apically extruded debris from each tooth was collected in pre-weighted glass vials and dried. The average weight of debris was assessed using a microbalance, and the data were analysed statistically using one-way analysis of variance and the post hoc Tukey multiple comparison test (α = 0.05). RESULTS: The PTU system was associated with significantly more debris than the other systems (P < 0.05). No significant differences were found between PTN, WO and R systems (P > 0.05). CONCLUSIONS: All systems were associated with apical debris extrusion when canals were prepared to a large apical size. The PTU system was associated with more debris extrusion.
Asunto(s)
Preparación del Conducto Radicular/instrumentación , Ápice del Diente/cirugía , Diente Premolar/cirugía , Humanos , Preparación del Conducto Radicular/métodosRESUMEN
OBJECTIVE: The aim of this study was to evaluate the composition of the salivary pellicle (SP) and multispecies biofilm developed on titanium nitrided by cold plasma. METHODS: Titanium discs were allocated into a control group (Ti) and an experimental group (TiN - titanium-nitrided by cold plasma). The disc surface topography was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The chemical composition of the disc surface was determined by X-ray photoelectron spectroscopy (XPS). Stimulated, clarified, and filtered saliva was used to form pellicles on the discs. Proteome analysis of the adsorbed SP proteins was performed by liquid chromatography-mass spectrometry (LC-MS). The surface free energy (SFE) was evaluated before and after SP formation. A multispecies biofilm composed of Actinomyces naeslundii, Streptococcus oralis, Streptococcus mutans, Fusobacterium nucleatum, Veillonella dispar, and Candida albicans was developed on the SP-coated discs. Viable microorganism counts were determined. The biomass and average thickness of biofilms were analyzed by confocal laser-scanning microscopy (CLSM) with COMSTAT software. The biofilm organization was visualized by SEM. RESULTS: The surface topography was similar in both groups. The SFE of the TiN group did not differ from that of the Ti group (p>0.05), although the adsorption of pellicle proteins increased the SFE in both pellicle-coated groups (p<0.001). Different proteins were identified on the Ti and TiN surfaces. The amount of biofilm was similar for both groups (p=0.416), but the counts of F. nucleatum and S. oralis were higher in the TiN group (p<0.001). Similar biofilms were characterized by the COMSTAT data, CLSM images, and SEM images. CONCLUSION: The titanium nitrided by cold plasma exhibited differences in SP composition and multispecies microbial biofilm population compared to the control titanium surface.