查看更多>>摘要：Purpose: To evaluate the fracture strength Of polyetheretherketone (PEEK) single crowns veneered with different materials produced by computer-aided design (CAD)-computer-aided manufacture (CAM) after aging. Methods: 60 stainless-steel master dies were prepared with a 1 mm-wide deep chamfer. Sixty PEEK frameworks were produced with a CAD-CAM system for the right maxillary first molar tooth on the dies. PEEK frameworks were divided into six groups (n= 10) according to veneering materials (five CAD-CAM materials and a resin composite). Group ZR: monolithic zirconia (Upcera ST-Color); Group EC: lithium disilicate glass-ceramic (IPS e.max CAD); Group LU: resin nano-ceramic (Lava Ultimate); Group VM: feldspathic ceramic (Vitablocs Mark II); Group VS: zirconia-reinforced lithium silicate glassceramic (VITA Suprinity); and Group CR: indirect resin composite (Gradia). All samples were subjected to a fracture strength test in a universal test device after thermo-mechanical aging and then the results were analyzed statistically using one-way ANOVA and Tukey’s post hoc test. In addition, post-fracture analyses of all samples were performed with a stereomicroscope. Results: The differences in fracture strength values of different veneer materials in single crowns with a PEEK framework were statistically significant (P< 0.05). Fracture strength was highest in Group ZR (1665 N), followed by Groups LU (1440 N), EC (1249 N), CR (918 N), VS (754 N), and VM (655 N).
查看更多>>摘要：Purpose: To evaluate the hardness profile of three resin-based restorative composites (RBC) (Filtek Z250XT, Filtek One Bulk Fill, Filtek Bulk Fill Flow) polymerized by a multi-wave curing light. Methods: Specimens (n= 12) were prepared by inserting 2 mm RBC increments into a split-mold and polymerized from the top using either 20- or 40-second exposure times. Specimen curing was performed directly at a 1 mm distance (control-group) or through an ivorine-tooth slot preparation at a 5 mm distance (experimental-group). Specimens were stored (37 ± 1°C/24 hours), then subjected to Knoop indenter (25g/5 seconds). Specimens’ KHN values were obtained from the upper and lower surfaces. Relative hardness (RH) (lower-to-upper ratio) was calculated for each specimen. Data were analyzed with three-way ANOVA and Tukey’s HSD (a= 0.05). Results: There was no significant RH difference among RBCs in the control group, regardless of the exposure time (P> 0.05). Average RH ratios for all RBCs tested in this group were greater than 0.80. However, the average RH values of the experimental RBC group were significantly lower. The RH for Z250 was 0.39 in the 20-second group, while RH was 0.63 in the 40-second group. BF had an RH ratio of 0.70 in the 20-second and 0.72 in the 40-second group, while One Bulk had a ratio of 0.65 in the 20-second and 0.71 in the 40-second groups. Doubled exposure time substantially increased RH of all tested materials at a 1 mm tip-to-material distance. Clinically relevant 5. mm light-tip to material-surface distance significantly reduced polymerization efficacy of RBC specimens, regardless of the exposure time.
查看更多>>摘要：Purpose: To do a systematic review and meta-analysis to determine whether laser treatment affects the bond strength of resin composites to recently bleached enamel. Methods: This report follows the Preferred Reporting Items for Systematic Reviews and Qualitative Analyses (PRISMA) statement. Medline via PubMed, Embase, Web of Science, and the Cochrane Library databases were searched with no limits on publication year. Two reviewers independently screened all titles and abstracts to perform the study selection, data extraction, and risk-of-bias assessments. A random-effects meta-analysis model was performed using Review Manager software (version 5.3, Cochrane Collaboration). Results: From the 93 records identified, seven articles that met all the inclusion criteria were included in the systematic review, and six studies were included in the meta-analysis. The overall results showed a statistically significant difference in bond strength between the control group and laser-treated group (P= 0.04; mean difference: 5.27; 95% confidence interval: 0.28 to 10.27), favoring the laser-treated group. Subgroup analyses revealed that the tooth source (bovine or human teeth) contributed to the effect of laser treatment on the bleached enamel.
Mohamed Elshirbeny ElawsyaMarmar Ahmed MontaserNoha Abdel-Mawea El-WassefyNadia Mohamed Zaghloul...
6页
查看更多>>摘要：Purpose: To evaluate the degree of conversion (DC), Vickers microhardness (VMH), and depth of cure of dual-cure and light-cure bulk-fill resin composites (BFRCs). Methods: One dual-cure (Fill-Up) and two light-cure (QuiXfil and Tetric N-Ceram Bulk Fill) BFRCs were investigated. For each tested BFRC, 11 cylindrical specimens (5 mm diameter, 4 mm height) were prepared, and light cured for 10 seconds (n= 11). DC was obtained by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and VMH was obtained using a VMH tester. The specimens were measured for DC and VMH at top and bottom surfaces. Statistical analysis was performed using two-way ANOVA, Tukey’s post-hoc, and Pearson correlation tests (P< 0.05). Results: Fill-Up and Tetric N-Ceram Bulk Fill revealed significantly higher DC and VMH values on the top surfaces than that on the bottom surfaces, whereas QuiXfil revealed no significant difference between top and bottom surfaces for DC and VMH. All tested BFRCs showed bottom/top ratios >80% for both DC and VMH. Each tested BFRC showed a significant positive correlation between DC and VMH. All tested BFRCs had adequate depth of cure, but only QuiXfil had a uniform depth of cure. Both DC and VMH bottom/top ratios were effective for depth of cure evaluation. ^y>185-190
Jamele Menezes de SouzaJo?o Paulo Alves da Silva AguiarWashington José Batista das NevesLuís Felipe Espindola-Castro...
6页
查看更多>>摘要：Purpose: To evaluate the influence of diet and exposure to red wine on the treatment velocity, clinical results, postoperative tooth sensitivity, and patient satisfaction after tooth bleaching. Methods: 45 subjects undergoing home bleaching with 16% carbamide peroxide (CP) were randomly separated into three groups, depending on the restriction of colored food and the use of a red wine mouthwash. Shades of teeth 11 and 21 were assessed using a digital spectrophotometer (VITA Easy Shade) at TO (before treatment), T7 (7 days after treatment), T15 (15 days after treatment), and T30 (30 days after treatment). The assessments were verified using the CIELab system (values of L*, a*, and b*) and the change in shade was calculated (AE, AL, Aa, and Ab). Results: No statistically significant differences in AE, AL, Aa, and Ab were found between the groups. However, at T7, the group restricted from colored foods without red wine mouthwash had meaningful variations in L*, a*, and b*. Statistically, there was no difference in tooth sensitivity between the groups in the 7- and 15-day periods. Patients in the restricted colored foods without red wine mouthwash group were more satisfied after the end of treatment.
查看更多>>摘要：Purpose: To assess the prevalence of acute periapical abscesses (PAs) in patients with history of stroke. Methods: Integrated data of hospital patients was used. Data from the corresponding diagnosis codes for PAs and stroke were retrieved by searching the appropriate query in the database. The odds ratio (OR) of acute PAs and its association with post-stroke conditions was calculated and analyzed statistically. Results: The prevalence of acute PAs in patients with stroke history was 1.39% as compared to 0.6% in the general patient population of the hospital. The OR was 2.78 and the difference was statistically significant (P< 0.0001). The prevalence of acute PAs in patients with a history of hemorrhagic stroke was 1.19% and the OR was 2.38. The difference was statistically significant (P< 0.0001). The prevalence of acute PAs in patients with a history of cerebral infarction was 1.55% and the OR was 3.11. The difference was statistically significant (P< 0.0001). The prevalence of acute PAs in patients with a history of cerebral infarction without hypertension was 0.87% and the OR was 1.75. The difference was statistically significant (P< 0.0001).
Fatih DemirciMerve Birgealp ErdemSamet TekinCevdet Caliskan...
5页
查看更多>>摘要：Purpose: To evaluate the effects of ultrasonic scaling (US) and air polishing (AP) on four polyetheretherketone (PEEK) composites. Methods: One hundred-twenty 15 × 3 mm discs of PEEK specimens were divided into four groups (n=30): Unfilled PEEK(U-PEEK), carbon fiber-reinforced PEEK(CFR-PEEK), glass fiber-reinforced PEEK(GFR-PEEK), and ceramic-filled PEEK(CF-PEEK). Each group was further divided into three subgroups (n = 10): control, US, and AP. Profilometry and scanning electron microscopy were used to analyze and evaluate surface roughness (SR). Statistical analyses of the data obtained were conducted using Shapiro-Wilk, Welch, and Games-Howell tests. Results: When the SR values of the specimens with US cleaning were evaluated, a statistically significant difference was found between the groups (P< 0.05). When the SR values of the specimens with AP cleaning were analyzed, there was a statistically significant difference in the CF-PEEK group (P< 0.05), whereas the other groups were not significantly different (P> 0.05). More studies are needed on CFR-PEEK and GFR-PEEK materials offered as alternatives to CF-PEEK in dentistry.
查看更多>>摘要：Purpose: To investigate and compare the effects of the two widely used regenerative endodontics medicaments: Triple antibiotic paste (ciprofloxacine-metronidazole-clindamycin) and calcium hydroxide on the microhardness and degradation of human root dentin. Methods: Following ethical approval and subject consent to use teeth in this research study, 60 singled-rooted permanent human teeth were randomly divided into six groups: (1) Triantibiotic paste with distilled water, or with (2) propylene glycol, (3) calcium hydroxide with distilled water, (4) calcium hydroxide propylene glycol, (5) untreated extracted teeth as negative controls, or (6) teeth instrumented and filled with calcium hydroxide or tri-antibiotic paste as positive controls. The microhardness tests were conducted after 1 and 2 months of exposure to the medicaments using a Vickers microhardness tester. Raman spectroscopy and energy dispersive x-ray spectroscopy were used to evaluate the chemistry and structure of the root dentin. Results: There were differences in the dentin microhardness following treatment with the medicaments or controls (P< 0.05). The time of root dentin exposure to the medicaments was similar (P> 0.05). The root dentin microhardness was lower in the teeth treated with the triple antibiotic paste or calcium hydroxide when combined with propylene glycol. The root dentin collagen in these treated teeth were also significantly degraded when viewed with Raman spectroscopy and energy dispersive x-ray spectroscopy, whereas the inorganic phase (dentin) remained unaltered. Samples exposed to the antimicrobial agents with water as a vehicle exhibited stronger microhardness and less degradation.
查看更多>>摘要：Purpose: To test the applicability of autofluorescence (AF) spectrum and image in the detection and identification of oral pathogens. Methods: Oral pathogens (Candida albicans, Porphyromonas gingivalis, Streptococcus mutans) and teeth were used. To induce AF, the 405 nm laser was used as a fight source, and AF was obtained and observed using a spectrometer, fluorescence camera, and microscope, respectively. Results: The tested oral pathogens had similar spectral distributions, but their peak intensities and peak ratios were different. Their peak positions and spectral patterns were different from those of the tested sound and carious teeth. These differences were also found from the other referenced oral mucosa. Fluorescence image could localize the existence of oral bacteria. Oral pathogens could be imaged by fluorescence, but identification of each pathogen by image was not probable.
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