Evaluation of Cytotoxicity, Cell Attachment, and Elemental Characterization of Three Calcium Silicate-Based Sealers.

We investigated three calcium silicate-based sealers with respect to their chemical characterization, cytotoxicity, and attachment to RAW264.7 cells. BioRoot RCS (BR), Bio-C Sealer (BC), and Sealer Plus BC (SPBC) were assessed using Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), and energy-dispersive X-ray spectroscopy (EDX) (n = 4) for elemental characterization, and using scanning electron microscopy (SEM) to evaluate cell morphology and adhesion. Cytotoxicity was determined at different dilutions (1:1, 1:2, and 1:5) using the succinate dehydrogenase activity (MTT assay). Statistical analysis was performed for normal distribution using the Shapiro-Wilk test and for homoscedasticity using Levene's test, and one-way ANOVA, Tukey's/Dunnett's post hoc tests for cell viability and XRF (α = 0.05). Calcium silicate hydrate and calcium hydroxide were detected by FTIR in all groups. EDX detected a higher calcium content for BR and SPBC and aluminum only in the premixed sealers. XRF detected the highest calcium release in BR (p < 0.05). The surface morphology showed irregular precipitates for all the sealers. SPBC at a 1:2 dilution resulted in the lowest cell viability compared to BR (p < 0.05) and BC (p < 0.05). The calcium silicate-based sealers produced a statistically significant reduction in cellular viability at a 1:1 dilution compared to the control group (p < 0.0001). All the sealers maintained viability above 70%.

Effects of different calcium-silicate based materials on fracture resistance of immature permanent teeth with replacement root resorption and osteoclastogenesis.

Objectives: This study evaluated the effects of Biodentine (BD), Bio-C Repair (BCR), and mineral trioxide aggregate (MTA) plug on the fracture resistance of simulated immature teeth with replacement root resorption (RRR) and in vitro-induced osteoclastogenesis. Materials and Methods: Sixty bovine incisors simulating immature teeth and RRR were divided into 5 groups: BD and BCR groups, with samples completely filled with the respective materials; MTA group, which utilized a 3-mm apical MTA plug; RRR group, which received no root canal filling; and normal periodontal ligament (PL) group, which had no RRR and no root canal filling. All the teeth underwent cycling loading, and compression strength testing was performed using a universal testing machine. RAW 264.7 macrophages were treated with 1:16 extracts of BD, BCR, and MTA containing receptor activator of nuclear factor-kappa B ligand (RANKL) for 5 days. RANKL-induced osteoclast differentiation was assessed by staining with tartrate-resistant acid phosphatase. The fracture load and osteoclast number were analyzed using 1-way ANOVA and Tukey's test (α = 0.05). Results: No significant difference in fracture resistance was observed among the groups (p > 0.05). All materials similarly inhibited osteoclastogenesis (p > 0.05), except for BCR, which led to a lower percentage of osteoclasts than did MTA (p < 0.0001). Conclusions: The treatment options for non-vital immature teeth with RRR did not strengthen the teeth and promoted a similar resistance to fractures in all cases. BD, MTA, and BCR showed inhibitory effects on osteoclast differentiation, with BCR yielding improved results compared to the other materials.

Physicochemical properties and osteoclastogenesis for three premixed calcium silicate-based sealers post set.

Solubility, pH, ion release, cytotoxicity, and osteoclastogenesis inhibition in bone marrow-derived monocyte macrophages (BMMs) were evaluated in EndoSequence BC Sealer (END), Bio-C Sealer (BC), and Sealer Plus BC (SPBC). pH was determined after immersion of the sealers in deionized water (DW) and Minimum Essential Medium Alpha (α-MEM). Solubility was obtained by mass loss. Ion release was measured by using X-ray fluorescence spectroscopy (XRF). Cytotoxicity was evaluated by MTT assay. Inhibition of osteoclastogenesis was evaluated by tartrate-resistant acid phosphatase (TRAP). Data were analyzed using the t-test, ANOVA and Tukey/Dunnett's post-hoc tests (α = 0.05). END had the highest pH in DW (p < 0.05), and BC, in α-MEM (p < 0.05). Solubility in DW was the lowest for SPBC (p < 0.005). The highest calcium release was observed for BC in DW at 12 h (p < 0.05), and in α-MEM at 12 and 24 h (p < 0.05). The lowest toxicity was detected for END (p < 0.05). BC had the highest inhibitory effect on osteoclasts (p < 0.05). Overall, the highest solubility and pH values were found in DW. However, the calcium silicate-based sealer showed higher solubility than the ISO standards. Calcium release was the highest for BC. END showed the highest cell viability, and BC, the highest osteoclast inhibition.

Calcium-doped zinc oxide nanocrystals as an innovative intracanal medicament: a pilot study.

Objectives: This study investigated the cytotoxicity, radiopacity, pH, and dentinal tubule penetration of a paste of 1.0% calcium-doped zinc oxide nanocrystals (ZnO:1.0Ca) combined with propylene glycol (PRG) or polyethylene glycol and propylene glycol (PEG-PRG). Materials and Methods: The pastes were prepared by mixing calcium hydroxide [Ca(OH)2] or ZnO:1.0Ca with PRG or a PEG-PRG mixture. The pH was evaluated after 24 and 96 hours of storage in deionized water. Digital radiographs were acquired for radiopacity analysis and bubble counting of each material. The materials were labeled with 0.1% fluorescein and applied to root canals, and images of their dentinal tubule penetration were obtained using confocal laser scanning microscopy. RAW264.7 macrophages were placed in different dilutions of culture media previously exposed to the materials for 24 and 96 hours and tested for cell viability using the MTT assay. Analysis of variance and the Tukey test (α = 0.05) were performed. Results: ZnO:1.0Ca materials showed lower viability at 1:1 and 1:2 dilutions than Ca(OH)2 materials (p < 0.0001). Ca(OH)2 had higher pH values than ZnO:1.0Ca at 24 and 96 hours, regardless of the vehicle (p < 0.05). ZnO:1.0Ca pastes showed higher radiopacity than Ca(OH)2 pastes (p < 0.01). No between-material differences were found in bubble counting (p = 0.0902). The ZnO:1.0Ca pastes had a greater penetration depth than Ca(OH)2 in the apical third (p < 0.0001). Conclusions: ZnO:1.0Ca medicaments presented higher penetrability, cell viability, and radiopacity than Ca(OH)2. Higher values of cell viability and pH were present in Ca(OH)2 than in ZnO:1.0Ca.

Use of platelet-rich fibrin for bone repair: a systematic review and meta-analysis of preclinical studies.

This systematic review evaluated the potential utility of platelet-rich fibrin (PRF) in bone repair in animals. The question is: can the use of PRF in bone defects in healthy rats induce bone repair compared to clot? This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (Prisma). The protocol was registered with Prospero (CRD [42020162319]). The literature search involved nine databases, including grey literature. All studies evaluated the bone defects created in rats filled with PRF and clots (control). Biomaterial evaluation was also performed in this study. The risk of bias was assessed using the Systematic Review Center for Laboratory Animal Experimentation (Syrcle) tool for animal studies. A meta-analysis of quantitative data was performed to estimate the effect of PRF on bone repair in rats. Heterogeneity among the studies was assessed using the I2 statistic. The literature search retrieved 685 studies, 10 of which fulfilled the eligibility criteria, and 4 were included in the quantitative assessment. Analysis of the risk of bias revealed that most studies had a high risk of bias in performance and detection. Meta-analysis yielded divergent results and the absence of a statistically significant effect: PRF with control (standardized mean difference 2.54, 95% confidence interval -0.80-5.89; p = 0.14). In general, study heterogeneity was high (I2 ≥ 75.0%). The quality of the studies that influenced the conclusion of the review was based on the PICO, the sources and form of the search, the study selection criteria, the form of evaluation of publication bias, the evaluation of the quality of the studies, and data extraction by two researchers. PRF did not provide significant benefits for bone repair, resulting in unpredictable effects.

Antibacterial activity of Brazilian red propolis and in vitro evaluation of free radical production.

OBJECTIVE: This study aimed to evaluate the antibacterial activity of crude Brazilian red propolis (BRP) extract against anaerobic bacteria involved in primary endodontic infection. Additionally, we evaluate the cell viability and free radical production of human dental pulp fibroblasts (HDPF) in direct contact with mineral trioxide aggregate (MTA) and BRP. DESIGN: The Minimum Inhibitory Concentration, Minimum Bactericidal Concentration (MIC, MBC) and Minimum Inhibitory Concentration of Biofilm (MICB50) of BRP against anaerobic endodontic pathogens were determined. HDPF were exposed to BRP10 (10 µg/mL), BRP50 (50 µg/mL), MTA extract (1:1, 1:2, 1:4 e 1:8), dimethyl sulfoxide 0.5% (DMSO), and cell culture medium (DMEM). The groups were tested for cell viability (MTT assay), and free radical production (reactive oxygen species - ROS, DCFH-DA probe and nitric oxide - NO, Griess reagent). The one-way ANOVA and Tukey's tests were employed at a significance level of 5%. RESULTS: MIC/MBC values of BRP performed antibacterial activity for Parvimonas micra (6.25/6.25 µg/mL), Fusobacterium nucleatum (25/25 µg/mL), Prevotella melaninogenica (50/100 µg/mL), Prevotella nigrescens (50/100 µg/mL), Prevotella intermedia (50/100 µg/mL), and Porphyromonas gingivalis (50/200 µg/mL). The MICB50 values ranged from 1.56 to 50 µg/mL. BRP and MTA stimulated cell viability, emphasizing BRP10 (p = 0.007). Furthermore, it was observed that MTA 1:1, MTA 1:2, and BRP50 slightly increased ROS (p < 0.001) and NO production (p = 0.008, p = 0.007, and p < 0.001 respectively) compared to DMEM group. CONCLUSIONS: BRP exhibits good antibacterial activity against endodontic pathogens, and both BRP and MTA promote the viability of HDPF without increasing NO and ROS production.

Ozone disinfection for viruses with applications in healthcare environments: a scoping review.

The aim of this scoping review was to provide sufficient information about the effectiveness of ozone gas in virus inactivation of surfaces and objects under different environmental conditions. The review was performed according to the list of PRISMA SrC recommendations and the JBI Manual for Evidence Synthesis for Scoping Reviews. The review was registered in Open Science Framework (OSF). EMBASE (Ovid), Lilacs, LIVIVO, MEDLINE (PubMed), SciELO, Scopus and Web of Science were primary sources, and "gray literature" was searched in OpenGray and OpenThesis. A study was included if it reported primary data on the effect of ozone gas application for vehicle-borne and airborne virus inactivation. No language or publication date restriction was applied. The search was conduct on July 1, 2020. A total of 16,120 studies were screened, and after exclusion of noneligible studies, fifteen studies fulfilled all selection criteria. Application of ozone gas varied in terms of concentration, ozone exposure period and the devices used to generate ozone gas. Twelve studies showed positive results for inactivation of different virus types, including bacteriophages, SARS-CoV-2 surrogates and other vehicle-borne viruses. Most of the studies were classified as unclear regarding sponsorship status. Although most of the population has not yet been vaccinated against COVID-19, disinfection of environments, surfaces, and objects is an essential prevention strategy to control the spread of this disease. The results of this Scoping Review demonstrate that ozone gas is promising for viral disinfection of surfaces.

Use of platelet-rich fibrin for bone repair: a systematic review and meta-analysis of preclinical studies

Abstract This systematic review evaluated the potential utility of platelet-rich fibrin (PRF) in bone repair in animals. The question is: can the use of PRF in bone defects in healthy rats induce bone repair compared to clot? This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (Prisma). The protocol was registered with Prospero (CRD [42020162319]). The literature search involved nine databases, including grey literature. All studies evaluated the bone defects created in rats filled with PRF and clots (control). Biomaterial evaluation was also performed in this study. The risk of bias was assessed using the Systematic Review Center for Laboratory Animal Experimentation (Syrcle) tool for animal studies. A meta-analysis of quantitative data was performed to estimate the effect of PRF on bone repair in rats. Heterogeneity among the studies was assessed using the I2 statistic. The literature search retrieved 685 studies, 10 of which fulfilled the eligibility criteria, and 4 were included in the quantitative assessment. Analysis of the risk of bias revealed that most studies had a high risk of bias in performance and detection. Meta-analysis yielded divergent results and the absence of a statistically significant effect: PRF with control (standardized mean difference 2.54, 95% confidence interval -0.80-5.89; p = 0.14). In general, study heterogeneity was high (I2 ≥ 75.0%). The quality of the studies that influenced the conclusion of the review was based on the PICO, the sources and form of the search, the study selection criteria, the form of evaluation of publication bias, the evaluation of the quality of the studies, and data extraction by two researchers. PRF did not provide significant benefits for bone repair, resulting in unpredictable effects.

Physicochemical properties and osteoclastogenesis for three premixed calcium silicate-based sealers post set

Abstract: Solubility, pH, ion release, cytotoxicity, and osteoclastogenesis inhibition in bone marrow-derived monocyte macrophages (BMMs) were evaluated in EndoSequence BC Sealer (END), Bio-C Sealer (BC), and Sealer Plus BC (SPBC). pH was determined after immersion of the sealers in deionized water (DW) and Minimum Essential Medium Alpha (α-MEM). Solubility was obtained by mass loss. Ion release was measured by using X-ray fluorescence spectroscopy (XRF). Cytotoxicity was evaluated by MTT assay. Inhibition of osteoclastogenesis was evaluated by tartrate-resistant acid phosphatase (TRAP). Data were analyzed using the t-test, ANOVA and Tukey/Dunnett's post-hoc tests (α = 0.05). END had the highest pH in DW (p < 0.05), and BC, in α-MEM (p < 0.05). Solubility in DW was the lowest for SPBC (p < 0.005). The highest calcium release was observed for BC in DW at 12 h (p < 0.05), and in α-MEM at 12 and 24 h (p < 0.05). The lowest toxicity was detected for END (p < 0.05). BC had the highest inhibitory effect on osteoclasts (p < 0.05). Overall, the highest solubility and pH values were found in DW. However, the calcium silicate-based sealer showed higher solubility than the ISO standards. Calcium release was the highest for BC. END showed the highest cell viability, and BC, the highest osteoclast inhibition.

Ozone disinfection for viruses with applications in healthcare environments: a scoping review

Abstract The aim of this scoping review was to provide sufficient information about the effectiveness of ozone gas in virus inactivation of surfaces and objects under different environmental conditions. The review was performed according to the list of PRISMA SrC recommendations and the JBI Manual for Evidence Synthesis for Scoping Reviews. The review was registered in Open Science Framework (OSF). EMBASE (Ovid), Lilacs, LIVIVO, MEDLINE (PubMed), SciELO, Scopus and Web of Science were primary sources, and "gray literature" was searched in OpenGray and OpenThesis. A study was included if it reported primary data on the effect of ozone gas application for vehicle-borne and airborne virus inactivation. No language or publication date restriction was applied. The search was conduct on July 1, 2020. A total of 16,120 studies were screened, and after exclusion of noneligible studies, fifteen studies fulfilled all selection criteria. Application of ozone gas varied in terms of concentration, ozone exposure period and the devices used to generate ozone gas. Twelve studies showed positive results for inactivation of different virus types, including bacteriophages, SARS-CoV-2 surrogates and other vehicle-borne viruses. Most of the studies were classified as unclear regarding sponsorship status. Although most of the population has not yet been vaccinated against COVID-19, disinfection of environments, surfaces, and objects is an essential prevention strategy to control the spread of this disease. The results of this Scoping Review demonstrate that ozone gas is promising for viral disinfection of surfaces.

Effect of irrigation protocols on root canal wall after post preparation: a micro-CT and microhardness study.

The aim of this study was to investigate the effects of different post space irrigation protocols for removing residual filling material from dentin walls, by using microcomputed tomography (micro-CT), and the influence of these protocols on dentin microhardness. Bovine incisors (n = 35) were filled with the single-cone technique and MTA Fillapex (Angelus, Londrina, PR, Brazil). Post space preparation (PSP) was performed 7 days after filling, using the Odous Touch electrical system (Odous De Deus Ind. e Com., Belo Horizonte, MG, Brazil), followed by post space irrigation using manual irrigation, passive ultrasonic irrigation, or Easy Clean, together with 2.5% sodium hypochlorite (NaOCl), or with 2.5% NaOCl and 17% EDTA (NaOCl/EDTA). Micro-CT scans were performed at three time points. The residual filling material was evaluated at three levels: cervical, middle and apical. The Knoop test was measured with four indentations around the canal lumen at three dentin depths: X (100 µm), Y (200 µm) and Z (400 µm). Statistical analysis was performed using ANOVA (p < 0.05). The effects of the activation method (p < 0.001), and the root level (p = 0.013), as well as the interaction between the irrigant and the activation method (p = 0.041), led to different percentages of residual filling material. Lower amounts of residual filling material were observed at the cervical versus the middle and apical levels (p < 0.05). No significant differences were observed in dentin microhardness (p > 0.05). The best removal of the residual filling material was performed using the Easy Clean tip and NaOCl/EDTA, regardless of the activation methods.

Cytotoxicity and dentin composition alterations promoted by different chemomechanical caries removal agents: A preliminary in vitro study.

BACKGROUND: The use of chemomechanical agents for caries removal has been indicated as a non-invasive treatment option; however, their possible deleterious effects on the dental-pulp complex have been insufficiently studied. This study assessed the direct cytotoxicity of two chemomechanical caries removal agents (Brix 3000™ - BX and Papacarie Duo™ - PD) on pulp cells from deciduous teeth, as well as to assess the morphology and chemical compositions of the dentin surface after the application of these materials. MATERIAL AND METHODS: The cells were seeded (50,000 cells/cm²) in a culture medium (DMEM with 10% fetal bovine serum - FBS). After 24 hours, the BX and PD materials were added to 1:20, 1:100, and 1:1000 dilutions. Non-exposed cells were considered as the control group. The viability test (MTT), Trypan Blue assay (TB), and cell morphology (Scanning Electron Microscopy - SEM) were performed after 24 hours of agent application. For the SEM and chemical (energy-dispersive X-ray spectrometry - EDS) dentin evaluation, 0.3-mm-thick dentin discs were obtained and divided into control group (no treatment) and surfaces covered with 37% phosphoric acid, BX, or PD. Data were compared by one-way ANOVA and Tukey's test (p<0.05). RESULTS: Decreases in cell viability and numbers of viable cells were observed for both materials, at all dilutions, when compared with the control group (p<0.05). The BX and PD materials did not cause visually perceptible changes, according to SEM, on the surfaces of dentin discs. The EDS analysis did not indicate a statistically significant difference in the levels of calcium (Ca) and phosphorus (P) between the materials and the control group (p>0.05). CONCLUSIONS: Both materials showed cytotoxicity when in direct contact with the pulp cells from deciduous teeth, and the BX material presented lower cytotoxicity than the PD material. Moreover, both materials did not significantly change the dentin composition. Key words:Cell culture, cytotoxicity, dental pulp, papacarie, primary teeth.

Biological parameters, discolouration and radiopacity of calcium silicate-based materials in a simulated model of partial pulpotomy.

AIM: To analyse the discolouration, radiopacity, pH and calcium ion release of Biodentine (BD), Bio-C repair (BCR) and Bio-C temp (BCT), as well as their biological effects on human dental pulp cells (hDPCs). METHODOLOGY: Sixty-four extracted bovine incisors were prepared to simulate crown fractures with pulp exposure and open root apex. The roots were filled using a mixture of agar and blood (control), and BD, BCR or BCT were placed over this mixture. Colour assessment analyses of the samples were performed before and immediately after material insertion and repeated at 30 and 90 days, using a spectrophotometer. The colour change of each specimen was evaluated at the crown and calculated based on the CIELab colour space. Digital radiographs were acquired for radiopacity analysis. hDPCs were placed in contact with different dilutions of culture media previously exposed to such materials and tested for cell viability using the MTT assay. The pH and calcium ion release of all materials were measured after 24 h; the data were assessed using one-way analysis of variance (ANOVA). Cell viability was analysed by two-way ANOVA. Differences in colour parameters and wound-healing data were assessed by two-way repeated measures ANOVA (α = 0.05). Tukey's and Dunnett's tests were used to compare the experimental groups with the control group. RESULTS: BCR had grater radiopacity and smaller colour alteration (ΔEab/ΔE00) than the other materials tested (p < .005; p < .001). No significant differences in pH were found amongst the tested materials (p > .05). BCT was associated with the largest release of calcium ions (p < .0001). BD had cell viability similar to that of the control at the lowest dilutions, and BCR was similar to that of the control, regardless of the dilution tested (p > .05). BCT had a lower percentage of viability than that of the control at all tested dilutions (p < .0001). Cell migration rates in BD and BCR were similar to those in the control group after 24 h and 48 h (p > .05), whilst BCT had larger voids than the control in both periods (p < .0001). CONCLUSIONS: BCR, BCT and BD were associated with tooth discolouration. BCR had the lowest staining values, the highest radiopacity and viability greater than 80% hDPCs.

Influence of chelating solutions on tubular dentin sealer penetration: A systematic review with network meta-analysis.

This systematic review assessed the influence of conventional final irrigation with chelating solutions (CS) on tubular dentin sealer penetration (TDSP). The literature search was conducted in eight electronic databases using MeSH, DeCS, EMTREE and free terms. The study protocol followed the PRISMA guidelines and was registered on the PROSPERO database (CRD42020203080). Twelve studies were included, and a qualitative synthesis and network meta-analysis of the data were performed. The risk of bias of the studies was assessed using an adaptation of the JBI Critical Appraisal tool. QMix was the solution with the highest probability of having the highest percentage of TDSP in the apical (34.1%), middle (86.5%) and coronal (97.7%) thirds. Eleven studies presented a moderate risk of bias, whereas one study presented a high risk of bias. In conclusion, CS improves sealer penetration into the dentinal tubules with QMix demonstrating superior results.

Accuracy of the dental pulp sensibility test using cold spray for the diagnosis of pulp diseases: an observational clinical study

The dental pulp sensibility test is one of the main auxiliary resources for the diagnosis of pulp pathologies, and its accuracy is still debatable. This cross-sectional observational study evaluated the accuracy of the pulp sensibility test (PST) using cold spray (1,1,1,2-tetrafluoroethane) for the diagnosis of pulp diseases and determined the effect of individual and clinical variables on the reliability of this test. The paper was designed following the STROBE statement. Sixty patients with indications for primary endodontic treatment were selected and examined from August 2017 to July 2018. Data collection was performed through interviews, clinical/radiographic examinations and the PST. The results of the cold test, along with data on sex, age, the tooth type regarding the root number, and the presence of restorations and caries, as well as the recent consumption of analgesics, were recorded. The presence of bleeding within the pulp chamber was used as the gold standard to compare with the clinical diagnosis and to identify the true-positive, false-positive, true-negative, and false-negative responses. The accuracy of PST achieved in subgroups of individual and clinical variables was compared using the chi-square test with a significance level of 5% (p < 0.05). The PST with the use of cold spray showed a sensitivity of 0.88, a specificity of 1.00, a positive predictive value of 1.00, a negative predictive value of 0.86, and an accuracy of 0.93. The accuracy of the cold spray was not affected by individual or clinical variables. The PST with the use of cold spray is an accurate and reliable method for determining the diagnosis of pulp diseases, especially in cases of pulp vitality or irreversible pulpitis.

Effect of irrigation protocols on root canal wall after post preparation: a micro-CT and microhardness study

Abstract: The aim of this study was to investigate the effects of different post space irrigation protocols for removing residual filling material from dentin walls, by using microcomputed tomography (micro-CT), and the influence of these protocols on dentin microhardness. Bovine incisors (n = 35) were filled with the single-cone technique and MTA Fillapex (Angelus, Londrina, PR, Brazil). Post space preparation (PSP) was performed 7 days after filling, using the Odous Touch electrical system (Odous De Deus Ind. e Com., Belo Horizonte, MG, Brazil), followed by post space irrigation using manual irrigation, passive ultrasonic irrigation, or Easy Clean, together with 2.5% sodium hypochlorite (NaOCl), or with 2.5% NaOCl and 17% EDTA (NaOCl/EDTA). Micro-CT scans were performed at three time points. The residual filling material was evaluated at three levels: cervical, middle and apical. The Knoop test was measured with four indentations around the canal lumen at three dentin depths: X (100 μm), Y (200 μm) and Z (400 μm). Statistical analysis was performed using ANOVA (p < 0.05). The effects of the activation method (p < 0.001), and the root level (p = 0.013), as well as the interaction between the irrigant and the activation method (p = 0.041), led to different percentages of residual filling material. Lower amounts of residual filling material were observed at the cervical versus the middle and apical levels (p < 0.05). No significant differences were observed in dentin microhardness (p > 0.05). The best removal of the residual filling material was performed using the Easy Clean tip and NaOCl/EDTA, regardless of the activation methods.

Effects of zinc oxide and calcium-doped zinc oxide nanocrystals on cytotoxicity and reactive oxygen species production in different cell culture models.

OBJECTIVES: This study aimed to synthesize nanocrystals (NCs) of zinc oxide (ZnO) and calcium ion (Ca2+)-doped ZnO with different percentages of calcium oxide (CaO), to evaluate cytotoxicity and to assess the effects of the most promising NCs on cytotoxicity depending on lipopolysaccharide (LPS) stimulation. MATERIALS AND METHODS: Nanomaterials were synthesized (ZnO and ZnO:xCa, x = 0.7; 1.0; 5.0; 9.0) and characterized using X-ray diffractometry, scanning electron microscopy, and methylene blue degradation. SAOS-2 and RAW 264.7 were treated with NCs, and evaluated for viability using the MTT assay. NCs with lower cytotoxicity were maintained in contact with LPS-stimulated (+LPS) and nonstimulated (-LPS) human dental pulp cells (hDPCs). Cell viability, nitric oxide (NO), and reactive oxygen species (ROS) production were evaluated. Cells kept in culture medium or LPS served as negative and positive controls, respectively. One-way analysis of variance and the Dunnett test (α = 0.05) were used for statistical testing. RESULTS: ZnO:0.7Ca and ZnO:1.0Ca at 10 µg/mL were not cytotoxic to SAOS-2 and RAW 264.7. +LPS and -LPS hDPCs treated with ZnO, ZnO:0.7Ca, and ZnO:1.0Ca presented similar NO production to negative control (p > 0.05) and lower production compared to positive control (p < 0.05). All NCs showed reduced ROS production compared with the positive control group both in +LPS and -LPS cells (p < 0.05). CONCLUSIONS: NCs were successfully synthesized. ZnO, ZnO:0.7Ca and ZnO:1.0Ca presented the highest percentages of cell viability, decreased ROS and NO production in +LPS cells, and maintenance of NO production at basal levels.

Effect of Endodontic Sealer in Young Molars Treated by Undergraduate Students - A Randomized Clinical Trial.

The progression of caries in permanent molar teeth of young patients, frequently result in endodontic treatment. This randomized blinded clinical trial assessed the effect of two endodontic sealers (Sealer 26 and AH Plus) on the incidence of pain and apical repair after endodontic treatment of young molar teeth, and secondly identify factors associated with the outcomes. Endodontic treatment was performed by undergraduate students in molar teeth (n=69) of young patients (n=54) at the Endodontic and Restorative Public Extension Clinic Service. Protaper Next was used and the endodontic sealers were allocated which were restored with direct composite resin. Two primary clinical outcomes - apical repair and postoperative pain, were assessed after 12 and 24 months for blinded operators. Description of incidence rates and mixed-model regression using Generalized Estimation Equations (GEE). After 2 years 69 molar teeth of 54 patients were evaluated. No effect of the endodontic sealer was observed irrespective of period of evaluation. Apical repair incidences and asymptomatic teeth were, respectively, 90.5 and 89.3, 96.8 and 90.0% during 1 and 2 years of follow-up. Failed apical repair was associated with unsatisfactory pulpectomy (p=0.003) and periapical conditions (p=0.007) as well as their interaction (p=0.016). None of these independent variables was able to predict the occurrence of pain in both periods. Prognosis of apical repair is dependent on the initial conditions. Endodontic treatment of young molars associated with composite resin restorations performed by undergraduate students have satisfactory results after 2 years and was effective to prevent the risk of permanent teeth loss.

Biomechanical and morphological changes produced by ionizing radiation on bone tissue surrounding dental implant.

OBJECTIVE: This study analyzed the effect of ionizing radiation on bone microarchitecture and biomechanical properties in the bone tissue surrounding a dental implant. METHODOLOGY: Twenty rabbits received three dental morse taper junction implants: one in the left tibia and two in the right tibia. The animals were randomized into two groups: the nonirradiated group (control group) and the irradiated group, which received 30 Gy in a single dose 2 weeks after the implant procedure. Four weeks after the implant procedure, the animals were sacrificed, and the implant/bone specimens were used for each experiment. The specimens (n=10) of the right tibia were examined by microcomputed tomography to measure the cortical volume (CtV, mm3), cortical thickness (CtTh, mm) and porosity (CtPo, %). The other specimens (n=10) were examined by dynamic indentation to measure the elastic modulus (E, GPa) and Vickers hardness (VHN, N/mm2) in the bone. The specimens of the left tibia (n=10) were subjected to pull-out tests to calculate the failure load (N), displacement (mm) up to the failure point and interface stiffness (N/mm). In the irradiated group, two measurements were performed: close, at 1 mm surrounding the implant surface, and distant, at 2.5 mm from the external limit of the first measurement. Data were analyzed using one-way ANOVA, Tukey's test and Student's t-test (α=0.05). RESULTS: The irradiated bone closer to the implant surface had lower elastic modulus (E), Vickers hardness (VHN), Ct.Th, and Ct.V values and a higher Ct.Po value than the bone distant to the implant (P<0.04). The irradiated bone that was distant from the implant surface had lower E, VHN, and Ct.Th values and a higher Ct.Po value than the nonirradiated bone (P<0.04). The nonirradiated bone had higher failure loads, displacements and stiffness values than the irradiated bone (P<0.02). CONCLUSION: Ionizing radiation in dental implants resulted in negative effects on the microarchitecture and biomechanical properties of bone tissue, mainly near the surface of the implant.

Lateral Luxation of Incisor - A Case Report of Using a New Cone-Beam Computed Tomography Software and Reposition Guideline.

Lateral luxation injuries are one of the most severe periodontal injuries in dental trauma. The correct diagnosis followed by repositioning of the tooth on the right position is fundamental for the periodontal ligament healing. This study reported a clinical case of lateral luxation of maxillary central incisor involving a new cone beam computed tomography (CBCT) software for reconstruction (e-Vol DX) to confirm the lateral luxation after no conclusive dental trauma injury definition by using conventional exam. The lateral luxation injury was digitally reduced by insertion of tooth back to its alveolus, and at the same session, the tooth was stabilized with a rigid splint and further changed to a semi-rigid nylon splint. During the pulpal status monitoring, the pulp was diagnosed necrotic, then the root canal was treated to prevent root resorption. External office-bleaching and restorative procedure was performed. The 4-years follow up and new imaging exam and digital reconstruction confirmed bone healing and no complication. CBCT images analyzed by eVol DX can be used to determine and to guide lateral luxation treatment.