Effect of Additional Apical Preparation on Retreatment of Curved Root Canals Filled with Different Sealers.

OBJECTIVE: This study assessed the influence of additional apical preparation on material removal during retreatment of curved root canals filled with different sealers. MATERIALS AND METHODS: Twelve mesial roots of mandibular molars with two separate canals and curvature between 25 and 35 degrees were selected. The working length was established 1-mm short of the apical foramen, and all the root canals were prepared using ProDesign R (PDR) 25/0.06. After preparation, the root canals were divided in two groups (n = 12) and filled by continuous wave condensation technique with NeoMTA Plus or AH Plus. All the root canals were retreated using rotary ProDesign Logic RT 25/0.08, reciprocating PDR 25/0.06 and apical preparation with PDR 35/0.05. Additional apical preparation was performed with ProDesign Logic (PDL) 50/0.01. The samples were scanned using a Skycan 1176 micro-computed tomography (micro-CT), voxel size 8.74 µm, before and after the retreatment procedures. Percentages of remaining filling material were evaluated. STATISTICAL ANALYSIS: The data were submitted to paired and unpaired t-tests (α = 0.05). RESULTS: Percentage of remaining filling material was similar between the root canals filled with NeoMTA Plus or AH Plus sealer after retreatment using PDR 35/0.05, and after additional apical preparation using PDL 50/0.01 (p > 0.05). However, PDL 50/0.01 significantly decreased the percentage of remaining filling material in the apical third after the additional apical preparation for both sealers (p < 0.05). CONCLUSION: NeoMTA Plus or AH Plus did not influence the retreatment of curved root canals. ProDesign Logic 50/0.01 promoted greater filling material removal in the apical third.

Comparison of Bio-C Pulpo and MTA Repair HP with White MTA: effect on liver parameters and evaluation of biocompatibility and bioactivity in rats.

AIM: To evaluate the tissue response promoted by Bio-C Pulpo (Bio), MTA Repair HP (MTA-HP) and White MTA (WMTA) and whether these materials cause liver changes in a rat experimental model. METHODOLOGY: Polyethylene tubes filled with Bio, MTA-HP and WMTA, and empty tubes (control group, CG) were implanted into the subcutaneous tissues of rats for 7, 15, 30 and 60 days. Inflammatory reaction score (IRS), capsule thickness, number of inflammatory cells (IC), von Kossa reaction, interleukin-6 (IL-6) and alkaline phosphatase (ALP) immunohistochemistry reactions were performed. Combined methods, von Kossa followed by immunohistochemistry for detection of ALP, were performed. At 60 days, the serum glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels were measured and liver fragments were collected for histological analysis; the data were assessed by one-way ANOVA analysis followed by Sidak's post-test. The biocompatibility and bioactivity data were subjected to the two-way ANOVA analysis followed by Tukey post hoc test, except the IRS. The IRS data were subjected to the Kruskal-Wallis ANOVA non-parametric test followed by Dunn's test (p ≤ .05). RESULTS: No significant difference was detected in serum GOT and GPT concentrations and in the number of hepatocytes among the experimental and CG samples. Although Bio-C Pulpo had the highest IC and IL-6-immunolabelled cells (p < 0.0001) at all periods, no significant difference was observed in the IRS among the materials, except at 60 days. In this period, the WMTA had lower IRS. All groups had a significant reduction in the capsule thickness and in the number of IC and IL-6-immunolabelled cells over time. Bio-C Pulpo, MTA-HP and WMTA specimens had greater immunoexpression of ALP than CG (p < .0001). At all periods, von Kossa-positive and birefringent structures were observed in the capsules around the materials. ALP-immunolabelled cells were also seen near von Kossa-positive structures. CONCLUSIONS: Bio-C Pulpo, MTA-HP and WMTA materials did not cause morphological changes in the liver and no significant alteration in the serum GOT and GPT levels. Moreover, these bioceramic materials were biocompatible and exhibited bioactive potential. However, Bio-C Pulpo induced greater inflammatory infiltrate than MTA-HP and WMTA at all periods.

Development and evaluation of reparative tricalcium silicate-ZrO2 -Biosilicate composites.

Biosilicate is a bioactive glass-ceramic used in medical and dental applications. This study evaluated novel reparative materials composed of pure tricalcium silicate (TCS), 30% zirconium oxide (ZrO2 ) and 10 or 20% biosilicate, in comparison with Biodentine. Setting time was evaluated based on ISO 6876 standard, radiopacity by radiographic analysis, solubility by mass loss, and pH by using a pH meter. Cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and NR assays. Alkaline phosphatase (ALP) activity and alizarin red were used to evaluate cell bioactivity. Antimicrobial activity was assessed on Enterococcus faecalis by the direct contact test. The data were submitted to analysis of variance (ANOVA)/Tukey; Bonferroni and Kruskal-Wallis, and Dunn tests (α = 0.05). The association of Biosilicate with TCS + ZrO2 had appropriate setting time, radiopacity, and solubility, alkaline pH, and antimicrobial activity. TCS and Biodentine showed higher ALP activity in 14 days than the control (serum-free medium). All cements produced mineralized nodules. In conclusion, Biosilicate + TCS ZrO2 decreased the setting time and increased the radiopacity in comparison to TCS. Biosilicate + TCS ZrO2 presented lower solubility and higher radiopacity than Biodentine. In addition, these experimental cements promoted antimicrobial activity and mineralization nodules formation, suggesting their potential for clinical use.

Micro-CT evaluation of filling of flattened root canals using a new premixed ready-to-use calcium silicate sealer by single-cone technique.

The aim of this study was to evaluate the filling ability of a new premixed ready-to-use calcium silicate-based sealer, in comparison with an epoxy resin-based sealer by the single-cone technique in flattened root canals. Thirty-two flattened root canals of maxillary second premolars with buccal-lingual diameter 4 or more times larger than the mesio-distal diameter at 9 mm from the radiographic apex were selected. Root canals were prepared using Hyflex EDM 25/0.08 and additional preparation with ultrasonic tip Flatsonic and ProDesign Logic 25/0.03. After preparation, the root canals were filled with two root canal sealers (n = 16): Bio-C Sealer or AH Plus using the single-cone technique. Scanning was performed before and after root canal obturation using a Skycan 1176 micro-computed tomography (micro-CT) with an isotropic voxel size of 8.74 µm. The percentage of voids was analyzed in the cervical/middle thirds and in the apical third. Data were submitted to the Mann-Whitney test at a significance level of 5%. There was no statistical difference between Bio-C Sealer and AH Plus (p > .05). The percentage of voids in the cervical/middle thirds was 8.94% (1.33-39.95) for Bio-C Sealer and 9.30% (1.19-18.00) for AH Plus (p > .05). In the apical third, this percentage was 11.84% (4.85-27.00) for Bio-C Sealer and 9.21% (1.34-28.78) for AH Plus (p > .05). By using the single-cone technique, neither Bio-C Sealer nor AH Plus provided a voids-free root canal filling. Both sealers had similar filling ability in flattened root canals.

Influence of Powder-to-Gel Ratio on Physicochemical Properties of a Calcium Silicate Sealer / Influencia de la relación polvo-gel sobre las propiedades fisicoquímicas de un sellador de silicato de calcio

Abstract Differences in liquid-to-powder ratio can affect the properties of calcium silicate-based materials. This study assessed the influence of powder-to-gel ratio on physicochemical properties of NeoMTA Plus. Setting time (minutes), flow (mm and mm²), pH (at different periods), radiopacity (mm Al) and solubility (% mass loss) were evaluated using the consistencies for root repair material (NMTAP-RP; 3 scoops of powder to 2 drops of gel) and root canal sealer (NMTAP-SE; 3 scoops of powder to 3 drops of gel), in comparison to Biodentine cement (BIO) and TotalFill BC sealer (TFBC). Statistical analysis was performed using one-way ANOVA and Tukey tests (α=0.05). BIO had the shortest setting time, followed by NMTAP-RP and NMTAP-SE. TFBC showed the highest setting time and radiopacity. BIO, NMTAP-RP, and NMTAP-SE had similar radiopacity. All materials promoted an alkaline pH. NMTAP-RP/SE presented lower solubility than BIO and TFBC. Regarding the flow, TFBC had the highest values, followed by NMTAP-SE, and NMTAP-RP. BIO had the lowest flow. In conclusion, NMTAP in both powder-to-gel ratios showed high pH and low solubility. The increase in the powder ratio decreased the setting time and flow. These findings are important regarding the proper consistency and work time to clinical application.

Resumen Las diferencias en la proporción líquido/polvo pueden afectar las propiedades de los materiales a base de silicato de calcio. Este estudio evaluó la influencia de la proporción polvo/gel en las propiedades fisicoquímicas del cemento NeoMTA Plus. El tiempo de fraguado (minutos), la fluidez (mm y mm²), el pH (en diferentes períodos), la radiopacidad (mmAl) y la solubilidad (% de pérdida de masa) fueron evaluados utilizando las consistencias para el material de reparación radicular (NMTAP-RP; 3 cucharadas de polvo/2 gotas de gel) y para cemento sellador del conducto radicular (NMTAP-SE; 3 cucharadas de polvo/3 gotas de gel), en comparación con el cemento Biodentine (BIO) y el cemento TotalFill BC (TFBC). El análisis estadístico se realizó utilizando las pruebas ANOVA y Tukey unidireccionales (α=0.05). BIO tuvo el tiempo de fraguado más corto, seguido de NMTAP-RP y NMTAP-SE. TFBC mostró el mayor tiempo de fraguado y radiopacidad. BIO, NMTAP-RP y NMTAP-SE tuvieron una radiopacidad similar. Todos los materiales promovieron un pH alcalino. NMTAP-RP/ SE tuvieron una solubilidad menor que BIO y TFBC. Con respecto a la fluidez, TFBC tuvo los valores más altos, seguido de NMTAP-SE y NMTAP-RP. BIO tuvo la fluidez más baja. En conclusión, NMTAP en la relación polvo/gel mostró un pH alto y una baja solubilidad. El aumento en la proporción de polvo disminuyó el tiempo de fraguado y la fluidez. Estos hallazgos son importantes con respecto a su consistencia y tiempo de trabajo durante la aplicación clínica.

Biodentine and MTA modulate immunoinflammatory response favoring bone formation in sealing of furcation perforations in rat molars.

OBJECTIVES: Evaluate the tissue reaction of periodontium subjacent to furcation perforations in rat molars sealed with Biodentine or mineral trioxide aggregate (MTA). MATERIALS AND METHODS: The pulp chamber floor of right upper first molars of 60 rats was perforated and filled with Biodentine, MTA, or cotton pellet (sham); the left first molars were used as control. After 7, 15, 30, and 60 days, maxillary fragments were processed for paraffin-embedding. The periodontal space (PS), volume density of inflammatory cells (VvIC) and fibroblasts (VvFb), number of osteoclasts, and collagen content were obtained. Interleukin-6 (IL-6) and osterix (osteoblast marker) were detected by immunohistochemistry. The data were submitted to ANOVA and Tukey's test (p ≤ 0.05). RESULTS: At 7 days, high values in VvIC, IL-6-immunolabeled cells, and osteoclasts were accompanied by reduced collagen content in enlarged PS of experimental groups. At all periods, VvIC, number of osteoclasts and IL-6, and PS were higher in sham than in Biodentine and MTA (p < 0.0001). From 7 to 60 days, significant reduction in VvIC, IL-6 immunoexpression, and osteoclasts was accompanied by significant increase in VvFb, osteoblasts, and collagen in Biodentine and MTA groups. At 60 days, significant differences in VvIC, PS, IL-6, osteoclasts, and osteoblasts were not found between Biodentine and MTA. Significant differences in the osteoclast number were not observed among Biodentine, MTA, and control groups while osteoblasts number was higher in Biodentine and MTA groups. CONCLUSIONS: Despite the initial inflammatory reaction and bone resorption, the sealing of furcation perforations with Biodentine and MTA favors the repair of periodontal tissues. CLINICAL RELEVANCE: Biodentine and MTA exhibit potential as repair material in the treatment of furcation perforations.

Tissue Response and Immunoexpression of Interleukin 6 Promoted by Tricalcium Silicate-based Repair Materials after Subcutaneous Implantation in Rats.

INTRODUCTION: The aim of the present study was to evaluate the inflammatory response induced by experimental tricalcium silicate cement with 20% zirconium oxide (TSC) and MTA Plus (MTAP; Avalon Biomed Inc, Bradenton, FL) in rat subcutaneous tissues. METHODS: Polyethylene tubes were filled with TSC (n = 20) and MTAP (n = 20) and implanted in the dorsal subcutaneous tissues of 32 rats. Empty tubes were used as the control (control group [CG], n = 20). After 7, 15, 30, and 60 days, the tubes with connective tissue were removed, and the inflammatory cells and immunolabeled cells for interleukin 6 (IL-6) were counted. Data were statistically analyzed using analysis of variance and the Tukey test (P ≤ .05). RESULTS: An increased number of inflammatory and immunolabeled cells for IL-6 were observed at 7 days. The number of inflammatory cells was higher for TSC and MTAP than the CG (P < .001) at 7 days; after 30 and 60 days, no significant differences were observed among the TSC, MTAP, and CG (P = .955). The number of immunolabeled cells for IL-6 was similar for TSC, MTAP, and CG at all evaluated periods. A gradual and significant decrease was observed in the number of inflammatory cells and IL-6-immunopositive cells. At 60 days, the capsules adjacent to TSC and MTAP exhibited fibroblasts and bundles of collagen fibers. CONCLUSIONS: TSC and MTAP caused a similar subcutaneous reaction in rats, suggesting that they are biocompatible and present similar immune responses.

Cytotoxicity, genotoxicity and antibacterial activity of poly(vinyl alcohol)-coated silver nanoparticles and farnesol as irrigating solutions.

OBJECTIVE: To evaluate the cytotoxicity, genotoxicity and antibacterial activity of poly(vinyl alcohol)-coated silver nanoparticles (AgNPs-PVA) and farnesol (FAR). DESIGN: The cytotoxicity (% of cell viability) was evaluated by MTT assay and the genotoxicity (% of DNA in the tail) was evaluated by Comet assay. Root canal disinfection with different irrigating protocols was evaluated ex vivo in human teeth contaminated with Enterococcus faecalis for 21days. Three microbiological samples were collected: initial (after contamination); post-irrigation (after irrigation); and final (after 7days). After each sample, the number of log 10 CFU mL-1 was determined. Statistical analyses was performed using two-way ANOVA and Bonferroni post-hoc tests for MTT assay, Kruskal-Wallis and Dunn post-hoc tests for Cometa and antibacterial assays (α=0.05). RESULTS: The MTT assay showed that AgNPs and FAR were less cytotoxic that sodium hypochlorite (NaOCl) and showed a lower% of DNA in the tail, in comparison with H2O2 (positive control - C+). In the post-irrigation microbiological sample, all the irrigating protocols were more effective than C+ (without irrigation). NaOCl/saline, NaOCl/saline/AgNPs-PVA and NaOCl/saline/FAR led to complete bacterial elimination (p >0.05). In comparison with the initial sample, both the post-irrigation and the final samples showed microbial reduction (p < 0.05). CONCLUSIONS: AgNPs-PVA and FAR showed low cytotoxicity and genotoxicity, and exhibit potential for use as a final endodontic irrigation protocols.

Physicochemical properties of calcium silicate cements associated with microparticulate and nanoparticulate radiopacifiers.

OBJECTIVES: The objective of this paper was to evaluate the physicochemical properties of calcium silicate cements with different chemical compositions, associated with radiopacifying agents. MATERIALS AND METHODS: Mineral trioxide aggregate (MTA) Angelus, calcium silicate cement with additives (CSC), and resinous calcium silicate cement (CSCR) were evaluated, with the addition of the following radiopacifiers: microparticles (micro) or nanoparticles (nano) of zirconium oxide (ZrO(2)), niobium oxide (Nb(2)O(5)), bismuth oxide (Bi(2)O(3)), or calcium tungstate (CaWO(4)). Setting time was evaluated using Gilmore needles. Solubility was determined after immersion in water. The pH and calcium ion release were analyzed after 3, 12, and 24 h and 7, 14, and 21 days. The data obtained were submitted to analysis of variance and Tukey's test, at a level of significance of 5 %. RESULTS: CSC + CaWO(4) and CSCR + ZrO(2) micro, Nb(2)O(5) and CaWO(4) presented results similar to MTA, with a shorter final setting time than the other associations. CSC and CSCR+ ZrO(2) micro presented a higher degree of flow. All the cements evaluated presented low solubility. The materials presented alkaline pH and released calcium ions. CONCLUSIONS: ZrO(2) micro radiopacifier may be considered a potential substitute for Bi(2)O(3) when associated with CSC or CSCR. CLINICAL RELEVANCE: The proposed materials, especially when associated with ZrO(2), are potential materials for use as alternatives to MTA.

Antimicrobial Activity and pH of Calcium Hydroxide and Zinc Oxide Nanoparticles Intracanal Medication and Association with Chlorhexidine.

AIM: To evaluate pH and antibacterial activity of pastes with calcium hydroxide [Ca(OH)2] and zinc oxide (ZnO) microparticles (micro) or nanoparticles (nano) and association with 0.4% chlorhexidine against Enterococcus faecalis. MATERIALS AND METHODS: The following pastes were analyzed: Ca(OH)2/ZnO micro, (2) Ca(OH)2/ZnO nano, (3) Ca(OH)2/ ZnO micro + 0.4% chlorhexidine, (4) Ca(OH)2/ZnO nano + 0.4% chlorhexidine. Antibacterial activity against E. faecalis was evaluated by agar diffusion test. The direct contact test on planktonic cells of E. faecalis was performed for 30 and 60 seconds. Root canals from bovine teeth were filled with the pastes and pH was evaluated after 1, 7, 14, 21, 30 and 60 days. The data obtained were submitted to the statistical tests analysis of variance (ANOVA) and Tukey or Kruskal-Wallis and Dunn test, with a 5% significance level. RESULTS: Calcium hydroxide and zinc oxide nano, and the pastes with 0.4% chlorhexidine were more effective in agar diffusion test. In the direct contact test, the pastes with chlorhexidine showed the highest effect after 30 seconds. All pastes eliminated E. faecalis after 60 seconds. All pastes promoted an increase in pH. The highest increase in pH was observed with nanoparticle medications after 1 and 7 days (p < 0.05). After this period, the pastes presented similar pH increase. CONCLUSION: It was concluded that calcium hydroxide and zinc oxide nanoparticles promoted greater initial alkalinization. The antimicrobial activity of the pastes against E. faecalis is favored by the association with chlorhexidine. CLINICAL SIGNIFICANCE: Although nanoparticles of calcium hydroxide and zinc oxide promoted antibacterial effect, the activity against E. faecalis is favored by association with chlorhexidine.

Antiseptic mouthwashes: in vitro antibacterial activity.

Mouthwashes are used as an adjunct to tooth brushing for improving breath and preventing oral diseases. The aim of this study was to compare the in vitro Maximum Inhibitory Dilution (MID) of 3 mouthwashes with different active ingredients against mutans streptococci (MS). The products analyzed were Periogard®, Cepacol® and Plax® Fresh Mint. Their antibacterial activity was assessed in duplicate in 96-well microtiter plates against 36 clinical isolates of MS. Each mouthwash was submitted to a serial two-fold dilution (1/2.5 to 1/5120) using double concentration of Tryptose Soy Broth with 1.0% yeast extract. The final volume in each well was 100 mL plus 5 mL of a bacterial suspension, equivalent to 107 CFU/mL. They were incubated microaerobically at 37 °C for 48 hours and the MIDs determined. MID was 1/320 for Periogard® and Cepacol®, and 1/20 for PlaxR® Statistical analysis revealed that the MID of Periogard® MID did not differ from that of Cepacol® (p>0.05), and was higher than that of Plax® (p<0.05). In conclusion, the antiseptic mouthwashes containing chlorhexidine (Periogard®) and cetylpyridinium chloride (Cepacol®) had higher in vitroantibacterial activity (MID) against MS than the antiseptic mouthwash containing triclosan (Plax®), according to microbiological method employed.

Niobium pentoxide as radiopacifying agent of calcium silicate-based material: evaluation of physicochemical and biological properties.

OBJECTIVES: The physicochemical properties and the tissue reaction promoted by microparticulated or nanoparticulated niobium pentoxide (Nb2O5) added to calcium silicate-based cement (CS), compared to MTA-Angelus™, were evaluated. MATERIALS AND METHODS: Materials were submitted to the tests of radiopacity, setting time, pH, and calcium ion release. Polyethylene tubes filled with the materials were implanted into rats subcutaneously. After 7, 15, 30, and 60 days, the specimens were fixed and embedded in paraffin. Hematoxylin & eosin (H&E)-stained sections were used to compute the number of inflammatory cells (IC). Interleukin-6 (IL-6) detection was performed, and the number of immunolabeled cells was obtained; von Kossa method was also carried out. Data were subjected to ANOVA and Tukey test (p ≤ 0.05). RESULTS: Nb2O5micro and Nb2O5nano provided to the CS radiopacity values (3.52 and 3.75 mm Al, respectively) superior to the minimum recommended. Groups containing Nb2O5 presented initial setting time significantly superior than mineral trioxide aggregate (MTA). All materials presented an alkaline pH and released calcium ions. The number of IC and IL-6 immunolabeled cells in the CS + Nb2O5 groups was significantly reduced in comparison to MTA in all periods. von Kossa-positive structures were observed adjacent to implanted materials in all periods. CONCLUSIONS: The addition of Nb2O5 to the CS resulted in a material biocompatible and with adequate characteristics regarding radiopacity and final setting time and provides an alkaline pH to the environment. Furthermore, the particle size did not significantly affect the physicochemical and biological properties of the calcium silicate-based cement. CLINICAL RELEVANCE: Niobium pentoxide can be used as radiopacifier for the development of calcium silicate-based materials.

Two- and tridimensional analysis of periapical repair after endodontic surgery.

OBJECTIVE: The aim of this study was to evaluate repair after endodontic surgery using two- and tridimensional imaging methods. MATERIALS AND METHODS: Periapical radiographs and cone beam computed tomography (CBCT) were performed before the surgeries and after 48 h (baseline), 4 months, and 8 months. The area (square millimeters) of periapical lesions in CBCT and in radiographs was compared regarding the percentage of repair. In the CBCT, multiple areas were converted to volume. Repeated-measures analyses and paired t tests (α = 0.05) were used to compare the methods. Correlation coefficients were calculated between the periods of evaluation within the CBCT volumetric analysis. Bland-Altman plots were used to compare the methods, based on the 95 % limits of agreement for the difference of the means. RESULTS: Baseline showed a larger lesion volume (192.54 mm(3)) than 4-month (79.79 mm(3)) and 8-month (47.51 mm(3)) periods. No differences were found in the percentage of repair in the first 4 months and after 8 months. The volumetric analysis showed a higher percentage of repair when the first and last 4 months were compared. No differences were found in the percentage of repair by area in the CBCTs. Repair of 73 % was obtained after 8 months. Similar results were observed by the Bland-Altman agreement analyses. CONCLUSIONS: The percentage of repair varied after 8 months, when lower values were obtained by volumetric evaluation. CLINICAL RELEVANCE: Considering the outcome at follow-up periods over 4 months, tridimensional evaluation by CBCT is more capable of determining the absence of periapical bone repair than conventional two-dimensional radiographs. Therefore, the use of CBCT would be suggested only for more complex cases with slower evolution of repair or for the association of factors that make prognosis difficult after surgery.

Filling of simulated lateral canals with gutta percha or resilon when using thermomechanical compaction.

AIMS: To evaluate the filling of simulated lateral canals with gutta-percha or Resilon when using thermomechanical compaction. SETTING AND DESIGN: Forty-five human single-rooted teeth were subjected to tooth decalcification and clearing. MATERIALS AND METHODS: After root canal preparation, artificial lateral canals were made at 2, 5, and 8 mm from the working length (WL), corresponding to the apical, middle, and cervical thirds, respectively. The specimens were divided (n = 15) according to the filling material: Dentsply gutta-percha (GD), Odous gutta-percha (GO), and Resilon cones (RE). Root canals were obturated by thermomechanical compaction using a #45 compactor and no sealer. Lateral canals were analyzed by digital radiography and digital images after tooth decalcification and clearing using the Image Tool software. STATISTICAL ANALYSIS USED: Data were subjected to the Kruskal-Wallis and Dunn tests at 5% significance. RESULTS: In the coronal third, RE and GO presented more filling ability than GD (P < 0.05). In the middle and apical thirds, RE presented the best results. CONCLUSIONS: Resilon demonstrated filling ability as material for root canal obturation by using thermomechanical compaction.

Microparticulated and nanoparticulated zirconium oxide added to calcium silicate cement: Evaluation of physicochemical and biological properties.

The physicochemical and biological properties of calcium silicate-based cement (CS) associated to microparticulated (micro) or nanoparticulated (nano) zirconium oxide (ZrO2 ) were compared with CS and bismuth oxide (BO) with CS. The pH, release of calcium ions, radiopacity, setting time, and compression strength of the materials were evaluated. The tissue reaction promoted by these materials in the subcutaneous was also investigated by morphological, immunohistochemical, and quantitative analyses. For this purpose, polyethylene tubes filled with materials were implanted into rat subcutaneous. After 7, 15, 30, and 60 days, the tubes surrounded by capsules were fixed and embedded in paraffin. In the H&E-stained sections, the number of inflammatory cells (ICs) in the capsule was obtained. Moreover, detection of interleukin-6 (IL-6) by immunohistochemistry and number of IL-6 immunolabeled cells were carried out. von Kossa method was also performed. The differences among the groups were subjected to Tukey test (p ≤ 0.05). The solutions containing the materials presented an alkaline pH and released calcium ions. The addition of radiopacifiers increased setting time and radiopacity of CS. A higher compressive strength in the CS + ZrO2 (micro and nano) was found compared with CS + BO. The number of IC and IL-6 positive cells in the materials with ZrO2 was significantly reduced in comparison with CS + BO. von Kossa-positive structures were observed adjacent to implanted materials. The ZrO2 associated to the CS provides satisfactory physicochemical properties and better biological response than BO. Thus, ZrO2 may be a good alternative for use as radiopacifying agent in substitution to BO.

Resistance of teeth with simulated incomplete rhizogenesis with intraradicular post or root canal filling.

AIM: The aim of this study was to evaluate the fracture strength (FS) of bovine incisors with simulated incomplete rhizogenesis (IR) after different intraradicular treatments. MATERIALS AND METHODS: Incomplete rhizogenesis was simulated by sectioning the crowns and roots of 40 bovine incisors. Root canal preparation was performed and the samples divided into 4 groups (n = 10): GI-negative control with intra-radicular preparation; GII-positive control without intra-radicular preparation; GIII-glass fiber post cemented with resin cement and GIV-root canal obturation with Epiphany/Resilon system. In GIII and GIV, 4.0 mm apical plugs of mineral trioxide aggregate (MTA) were done. The samples were embedded into cylinders with polystyrene resin, and the periodontal ligament was simulated with a medium-viscosity polyether-based impression material (Impregum Soft). The specimens were submitted to compressive fracture strength test (0.5 mm/min at 135° in relation to the long axis of the tooth) in a mechanical testing machine MTS 810. Data were submitted to ANOVA and Tukey's test (α = 0.05). RESULTS: GIII produced the highest FS values (p < 0.05). GI and GIV showed similar FS results (p > 0.05) but smaller than GII (p < 0.05). CONCLUSION: Glass fiber intraradicular posts provided the FS increase of teeth with simulated incomplete rhizogenesis. Epiphany/Resilon root canal flling with MTA plug did not provide the increase of the fracture strength to teeth with simulated incomplete rhizogenesis. CLINICAL SIGNIFICANCE: The fiber post reinforces the root structure of teeth with incomplete rhizogenesis.

Radiopacity and flow of different endodontic sealers.

The present study evaluated the radiopacity and flow of different endodontic sealers: AH Plus, Endo CPM, MTA Fillapex, Sealapex, Epiphany, and Epiphany SE. For the radiopacity test, six specimens measuring 10 mm in diameter and 1 mm in thickness were fabricated from each material. They were radiographed on an occlusal film alongside an aluminum step wedge. Radiographs were digitized to determine the radiopacity equivalence in millimeters of aluminum. To evaluate the flow, a 120 g load was placed on top of a glass slab containing 0.05 +/- 0.005 mll of sealer. The diameters of each material were measured (mm) with a caliper and samples were photographed. Digitized images were analyzed using the UTHSCSA Image Tool for Windows software, to determine the sealer area (mm2). Data were submitted to ANOVA and Tukey's test at 5% significance. AH Plus and Epiphany SE presented the greatest radiopacity (12.5 mm Al and 12.0 mm Al, respectively) (p > 0.05), followed by Epiphany (9.6 mm Al) and Fillapex (8.9 mm Al). Endo CPM (5.46 mm Al) and Sealapex (5.51 mm Al) presented lower radiopacity. MTA Fillapex presented significantly higher values of flow than other sealers (33.11 mm and 844.9 mm2). AH Plus, Epiphany, and Epiphany SE had similar values. Endo CPM (21.05 mm and 342.8 mm2) and Sealapex (19.98 mm and 352.5 mm2) presented the lowest flow values (p > 0.05). All sealers presented radiopacity and flow values according to ISO and ANSI/ADA recommendations.

Use of nanoparticulate zinc oxide as intracanal medication in endodontics: pH and antimicrobial activity.

The aim of this study was to evaluate the pH and antimicrobial activity of micro or nanoparticulate zinc oxide (ZnO) pastes with or without calcium hydroxide (CH). The following medications were evaluated: microparticulate ZnO + polyethylene glycol (PEG) 400; nanoparticulate ZnO + PEG 400; PEG 400; CH + microparticulate ZnO + PEG 400 and CH + nanoparticulate ZnO + PEG 400. The pH was assessed between 12 hours and 28 days, using a digital pH meter. The antimicrobial activity against Enterococcus faecalis (ATCC-9212), Candida albicans (ATCC-10231), Pseudomonas aeruginosa (ATCC-27853), Staphylococcus aureus (ATCC-6538) and Kocuria rhizophila (ATCC-9341) was determined in triplicate using agar diffusion test. The results were submitted to Kruskal-Wallis/Dunn and ANOVA/Tukey tests with 5% significance. The highest pH values were found for CH+ZnO, with higher values for nanoparticulate ZnO after 12 hours and 21 days (p < 0.05). CH+ZnO medication promoted higher growth inhibition against P. aeruginosa and lower against E. faecalis. Calcium hydroxide pastes have higher pH and antimicrobial activity when associated with either micro- or nanoparticulate zinc oxide.

Radiopacity and flow of different endodontic sealers. / Radiopacity and flow of different endodontic sealers.

The present study evaluated the radiopacity and flow of different endodontic sealers: AH Plus, Endo CPM, MTA Fillapex, Sealapex, Epiphany, and Epiphany SE. For the radiopacity test, six specimens measuring 10 mm in diameter and 1 mm in thickness were fabricated from each material. They were radiographed on an occlusal film alongside an aluminum step wedge. Radiographs were digitized to determine the radiopacity equivalence in millimeters of aluminum. To evaluate the flow, a 120 g load was placed on top of a glass slab containing 0.05 +/- 0.005 mll of sealer. The diameters of each material were measured (mm) with a caliper and samples were photographed. Digitized images were analyzed using the UTHSCSA Image Tool for Windows software, to determine the sealer area (mm2). Data were submitted to ANOVA and Tukeys test at 5

significance. AH Plus and Epiphany SE presented the greatest radiopacity (12.5 mm Al and 12.0 mm Al, respectively) (p > 0.05), followed by Epiphany (9.6 mm Al) and Fillapex (8.9 mm Al). Endo CPM (5.46 mm Al) and Sealapex (5.51 mm Al) presented lower radiopacity. MTA Fillapex presented significantly higher values of flow than other sealers (33.11 mm and 844.9 mm2). AH Plus, Epiphany, and Epiphany SE had similar values. Endo CPM (21.05 mm and 342.8 mm2) and Sealapex (19.98 mm and 352.5 mm2) presented the lowest flow values (p > 0.05). All sealers presented radiopacity and flow values according to ISO and ANSI/ADA recommendations.

Use of nanoparticulate zinc oxide as intracanal medication in endodontics: pH and antimicrobial activity. / Use of nanoparticulate zinc oxide as intracanal medication in endodontics: pH and antimicrobial activity.

The aim of this study was to evaluate the pH and antimicrobial activity of micro or nanoparticulate zinc oxide (ZnO) pastes with or without calcium hydroxide (CH). The following medications were evaluated: microparticulate ZnO + polyethylene glycol (PEG) 400; nanoparticulate ZnO + PEG 400; PEG 400; CH + microparticulate ZnO + PEG 400 and CH + nanoparticulate ZnO + PEG 400. The pH was assessed between 12 hours and 28 days, using a digital pH meter. The antimicrobial activity against Enterococcus faecalis (ATCC-9212), Candida albicans (ATCC-10231), Pseudomonas aeruginosa (ATCC-27853), Staphylococcus aureus (ATCC-6538) and Kocuria rhizophila (ATCC-9341) was determined in triplicate using agar diffusion test. The results were submitted to Kruskal-Wallis/Dunn and ANOVA/Tukey tests with 5

significance. The highest pH values were found for CH+ZnO, with higher values for nanoparticulate ZnO after 12 hours and 21 days (p < 0.05). CH+ZnO medication promoted higher growth inhibition against P. aeruginosa and lower against E. faecalis. Calcium hydroxide pastes have higher pH and antimicrobial activity when associated with either micro- or nanoparticulate zinc oxide.