Comparison of the rheological properties of four root canal sealers.
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ABSTRACT:
SUBMITTER: Chang SW
PROVIDER: S-EPMC4817532 | biostudies-other | 2015 Mar
REPOSITORIES: biostudies-other
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Project description:IntroductionThe aim of this study was to compare the shaping ability of four root canal preparation systems in newly developed 3D-printed root canal models.Materials and methodsFor this study, 1080 3D-printed acrylic resin blocks with nine different root canal configurations were produced. They were prepared with Reciproc R25 (#25), F6 SkyTaper (#25 and #30) F360 (#25 and #35) and One Shape (#25) (N = 30 per system). Pre- and post-instrumentation images were superimposed for evaluation of the centering ratio of the different systems. Ledges, instrument fractures and preparation times were also recorded. Analysis of variance (ANOVA) and post-hoc Tukey tests were conducted, comparing the mean canal centering ratios and the mean preparation times.ResultsThere were significant differences between all systems regarding the centering ratios in the different root canal configurations (ANOVA p < 0.001). The root canal configuration had considerable effect on the centering ratio of the instruments. The best overall mean centering ratios were achieved with F6 SkyTaper #25 instruments especially in canal configurations with big curvature angles and radii, while F360 #35 was least centered especially in canals with small curvature angles and radii. Most ledges occurred with OneShape, while it was the significantly (p < 0.001) fastest preparation system (86.7 s (SD 13.53)) and Reciproc the significantly (p < 0.001) slowest (103.0 s (SD 20.67)).Conclusion3D-printed root canals are suitable to produce challenging canal configurations and to investigate the limitations of root canal instruments. We found that all instruments caused canal transportations. However, F6 SkyTaper #25 files had better overall centering ratios than the other instruments. In canal configurations with small curvature radii, the centering ratio of some instruments is low and the probability for ledges is increased.
| S-EPMC6070255 | biostudies-literature
Project description:Calcium silicate-based bioactive glass has received significant attention for use in various biomedical applications due to its excellent bioactivity and biocompatibility. However, the bioactivity of calcium silicate nanoparticle-incorporated bioactive dental sealer is not much explored. Herein, three commercially available bioactive root canal sealers (Endoseal MTA (EDS), Well-Root ST (WST), and Nishika Canal Sealer BG (NBG)) were compared with a resin-based control sealer (AH Plus (AHP)) in terms of physical, chemical, and biological properties. EDS and NBG showed 200 to 400 nm and 100 to 200 nm nanoparticle incorporation in the SEM image, respectively, and WST and NBG showed mineral deposition in Hank's balanced salt solution after 28 days. The flowability and film thickness of all products met the ISO 3107 standard. Water contact angle, linear dimensional changes, and calcium and silicate ion release were significantly different among groups. All bioactive root canal sealers released calcium ions, while NBG released ~10 times more silicon ions than the other bioactive root canal sealers. Under the cytocompatible extraction range, NBG showed prominent cytocompatibility, osteogenecity, and angiogenecity compared to other sealers in vitro. These results indicate that calcium silicate nanoparticle incorporation in dental sealers could be a potential strategy for dental periapical tissue regeneration.
| S-EPMC7559325 | biostudies-literature
Project description:ObjectiveTo evaluate the effect of semiconductor laser irradiation on root canal sealing after routine root canal therapy (RCT).MethodsSixty freshly extracted single-rooted human teeth were randomly divided into six groups (n = 10). The anatomic crowns were sectioned at the cementoenamel junction and the remaining roots were prepared endodontically with conventional RCT methods. Groups A and B were irradiated with semiconductor laser at 1W for 20 seconds; Groups C and D were ultrasonically rinsed for 60 seconds as positive control groups; Groups E and F without treatment of root canal prior to RCT as negative control groups. Root canal sealing of Groups A, C and E were evaluated by measurements of apical microleakage. The teeth from Groups B, D and F were sectioned, and the micro-structures were examined with scanning electron microscopy (SEM). One way ANOVA and LSD-t test were used for statistical analysis (? = .05).ResultsThe apical sealing of both the laser irradiated group and the ultrasonic irrigated group were significantly different from the control group (p<0.5). There was no significant difference between the laser irradiated group and the ultrasonic irrigated group (p>0.5). SEM observation showed that most of the dentinal tubules in the laser irradiation group melted, narrowed or closed, while most of the dentinal tubules in the ultrasonic irrigation group were filled with tooth paste.ConclusionThe application of semiconductor laser prior to root canal obturation increases the apical sealing of the roots treated.
| S-EPMC5619785 | biostudies-literature
Project description:The understanding of the rheological and mechanical properties of nanoparticle aggregates is important for the application of nanofillers in nanocompoistes. In this work, we report a rheological study on the rheological and mechanical properties of nano-silica agglomerates in the form of gel network mainly constructed by hydrogen bonds. The elastic model for rubber is modified to analyze the elastic behavior of the agglomerates. By this modified elastic model, the size of the network mesh can be estimated by the elastic modulus of the network which can be easily obtained by rheology. The stress to destroy the aggregates, i.e., the yield stress (?y), and the elastic modulus (G') of the network are found to be depended on the concentration of nano-silica (?, wt.%) with the power of 4.02 and 3.83, respectively. Via this concentration dependent behavior, we can extrapolate two important mechanical parameters for the agglomerates in a dense packing state (? = 1): the shear modulus and the yield stress. Under large deformation (continuous shear flow), the network structure of the aggregates will experience destruction and reconstruction, which gives rise to fluctuations in the viscosity and a shear-thinning behavior.
| S-EPMC3211159 | biostudies-literature
Project description:Hinokitiol displays potent antimicrobial activity. It has been used in toothpaste and oral-care gel to improve the oral lichen planus and reduce halitosis. The aim of this study was to evaluate the antimicrobial activity of 3 different dental root canal sealers with hinokitiol (sealers+H) and their physical and biological effects. AH Plus (epoxy amine resin-based, AH), Apexit Plus (calcium-hydroxide-based, AP), and Canals (zinc-oxide-eugenol-based, CA), were used in this study. The original AH and CA exhibited strong anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity, but AP did not. The setting time, working time, flowability, film thickness, and solubility of each sealer+0.2%H complied with ISO 6876:2001. CA+0.2%H exhibited high cytotoxicity, but the others sealers+0.2%H did not. Because hinokitiol combined with Zn2+ in CA creates a synergistic effect. The physical tests of AP+0.5%-1%H complied with ISO 6876:2001, improved antimicrobial activity, inhibited inflammation genes cyclooxygenase-2 (COX-2) and hypoxia-inducible factor-1? (HIF-1?) mRNA in MG-63 cells and human gingival fibroblasts (HGF), and down-regulated lysyl oxidase (LOX) mRNA of HGF. In summary, AH and CA demonstrated strong antimicrobial activity, but AP did not. Application of hinokitiol increases AH anti-MRSA activity should less than 0.2% for keep well flowability. AP+0.5%-1% hinokitiol exhibited strong physical, antibacterial, and anti-inflammation potentials, and inhibited S. aureus abscess formation. Applying an appreciable proportion of hinokitiol to epoxy-amine-resin-based and calcium-hydroxide-based root canal sealers is warranted, but the enhanced cytotoxicity and synergistic effect must be considered.
| S-EPMC4051635 | biostudies-literature
Project description:Few studies have investigated smoking as a risk factor for root canal treatment. We studied the effect of smoking on the incidence of root canal treatment, controlling for recognized risk factors, in 811 dentate male participants in the VA Dental Longitudinal Study. Participants were not VA patients. Follow-up ranged from 2 to 28 years. Root canal treatment was verified on radiographs and evaluated with proportional hazards regression models. Compared with never-smokers, current cigarette smokers were 1.7 times as likely to have root canal treatment (p < 0.001), but cigar and/or pipe use was not significantly associated with root canal treatment. The risk among cigarette smokers increased with more years of exposure and decreased with length of abstinence. These findings suggest that there is a dose-response relationship between cigarette smoking and the risk of root canal treatment.
| S-EPMC2225991 | biostudies-literature
Project description:Samples from infected root canals of 43 teeth with chronic apical periodontitis were analyzed for the presence and relative levels of 83 oral bacterial species and/or phylotypes using a reverse-capture checkerboard hybridization assay. Associations between the most frequently detected taxa were also recorded. The most prevalent taxa were Olsenella uli (74%), Eikenella corrodens (63%), Porphyromonas endodontalis (56%), Peptostreptococcus anaerobius (54%), and Bacteroidetes oral clone X083 (51%). When prevalence was considered only for bacteria present at levels >10(5), Bacteroidetes clone X083 was the most frequently isolated bacterium (37%), followed by Parvimonas micra (28%), E. corrodens (23%), and Tannerella forsythia (19%). The number of target taxa per canal was directly proportional to the size of the apical periodontitis lesion, with lesions >10 mm in diameter harboring a mean number of approximately 20 taxa. Several positive associations for the most prevalent taxa were disclosed for the first time and may have important ecological and pathogenic implications. In addition to strengthening the association of several cultivable named species with chronic apical periodontitis, the present findings using a large-scale analysis allowed the inclusion of some newly named species and as-yet-uncultivated phylotypes in the set of candidate pathogens associated with this disease.
| S-EPMC2576597 | biostudies-literature
Project description:Millions of root canal treatments fail worldwide due to remnant bacteria deep in the dentinal tubules located within the dentine tissue of human teeth. The complex and narrow geometry of the tubules renders current techniques relying on passive diffusion of antibacterial agents ineffective. Here, the potential of actively maneuvered nanobots is investigated to disinfect dentinal tubules, which can be incorporated during a standard root canal procedure. It is demonstrated that magnetically driven nanobots can reach the depths of the tubules not possible with current clinical practices. Subtle alterations of the magnetic drive allow both deep implantations of the nanobots isotopically distributed throughout the dentine and spatially controlled recovery from selected regions, further supported by numerical simulations. Finally, the integration of bactericidal therapeutic modality with the nanobots is demonstrated, thereby validating the tremendous potential of nanobots in dentistry and nanomedicine in general.
| S-EPMC7613116 | biostudies-literature
Project description:BACKGROUND:The aim of the study was to assess bacterial sealability and bonding ability of methacrylate-based Resilon (RS, SybronEndo), Endo Rez (ER, Ultradent Products Inc), and epoxy-based AH Plus (AH, Dentsply/DeTrey), MTA Fill Apex (MTAF, Angelus Soluções Odontológicas) root canal sealers, and the effect of the smear layer removal on the sealability. METHODS:One hundred thirty root segments were instrumented up to apical size #60 and rinsed with 2.5% NaOCl. Half of the roots were rinsed with 5ml 17% EDTA to remove the smear layer. All the roots were filled with AH, ER, MTAF sealers and gutta-percha, or RS with Resilon cones. After storage at 37°C for 7 days the samples were mounted into bacterial leakage assay for 50 days. Another 100 roots were instrumented and rinsed as described above, split longitudinally, cut into the cervical, middle and apical parts. The sealers were injected through the plastic mould on the dentin surface. After 7 days of incubation at 37°C, bond strength was tested using a notched-edge test fixture (Crosshead, Ultradent Products Inc.) and a universal testing machine (Lloyd Instruments). RESULTS:AH revealed the longest mean time for bacterial resistance by 29.4 and 36.8 days (with and without smear layer, respectively) followed by RS (15.1 and 24.7 days, respectively). The difference between materials was significant (p<0.001). Bond strength values ranged from 0.2± 0.1 to 3.5± 0.7 MPa and increased from the apical to the cervical third. In the apical third, AH showed the highest mean (SD) bond values 1.4 (0.4) MPa and 1.7 (0.6) MPa (with and without smear, respectively, followed by RS, 0.5 (0.1) MPa and 0.8 (0.1) MPa, respectively. The difference between materials was significant (p=0.001). CONCLUSION:The effect of the smear layer removal on the sealability was material-dependent.
| S-EPMC6293555 | biostudies-other