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Leon Iversen opublikował 1 rok, 8 miesięcy temu
05).
For both porcelain groups, the 30-minute MAO groups showed higher bond strength values than those of the control groups (P<.05). In the Vita Titankeramik porcelain subgroup, the specimens coated with HA did not show any statistical differences compared with those of the control group (P>.05). Surface roughness was affected significantly (P<.001) by the coating procedure compared to that of the the control group.
Coating with either MAO or HA improved titanium-porcelain adhesion.
Coating with either MAO or HA improved titanium-porcelain adhesion.
Fractures of endodontically treated teeth have been attributed to weakened tooth structure caused by root canal enlargement and post preparation.
The purpose of this in vitro study was to evaluate the fracture resistance of roots filled with either gutta percha, composite resin (LuxaCore Dual), or calcium silicate-based cement (Biodentine).
One hundred twenty freshly extracted, human, permanent maxillary anterior teeth were sorted by type and assigned to 1 of 4 groups (n=30). The teeth in group NT were not endodontically treated and served as the control. The teeth in groups GP, LC, and, BD were accessed and instrumented to size 40/06. In group GP, the root canals were completely filled with gutta percha. In groups LC and BD, only the apical 5-mm portion of the root canals was filled with gutta percha, and the remaining portion of the root canals was filled with (LuxaCore Dual) in group LC and with (Biodentine) in group BD. Fracture resistance (kN) was assessed at the middle portion of each root, using a 3-point bending test with a universal testing machine exerting a compressive load on a loading pin at a crosshead speed of 0.5 mm/min until fracture occurred. One-way ANOVA was used to compare the mean root fracture resistance among the 4 groups (α=.05).
The mean ± SD fracture loads were 2.13 ±0.53 kN for group NT, 1.97 ±0.60 kN for group GP, 2.18 ±0.71 kN for group LC, and 2.22 ±0.54 kN for group BD. No statistically significant differences were found among the 4 groups (P>.05).
The roots of endodontically treated maxillary anterior permanent incisors filled with gutta percha, Biodentine, or LuxaCore Dual had resistance to fracture similar to that of teeth that were not endodontically treated.
The roots of endodontically treated maxillary anterior permanent incisors filled with gutta percha, Biodentine, or LuxaCore Dual had resistance to fracture similar to that of teeth that were not endodontically treated.
The use of monolithic zirconia crowns in implant prostheses is increasing, especially when the interdental space is insufficient. However, fractures have been reported in clinical practice.
The purpose of this study was to determine the minimal thickness of a complete zirconia crown used for an implant prosthesis in the posterior dental region.
Fifty complete zirconia crowns were produced using a computer-aided design/computer-aided manufacturing technique. In each group, 5 crowns of varying thicknesses (0.4, 0.5, 0.6, 0.7, and 0.8 mm) were subjected to cycles of vertical and 10-degree oblique compressive loading at 5 Hz and 300 N in a servohydraulic testing machine. Five finite element models comprising 5 different occlusal thicknesses (0.4, 0.5, 0.6, 0.7, and 0.8 mm) were simulated at 2 loading angles (0 and 10 degrees) and 3 loading forces (300, 500, and 800 N). Data were statistically analyzed, and fracture patterns were observed with a scanning electron microscope.
Cyclic loading tests revealed that the fracture resistance of the specimens was positively associated with prosthesis thickness (P<.01). Low von Mises stress values were obtained for prostheses with a minimal thickness of 0.7 mm under varying loading directions and forces.
Zirconia prostheses with a minimal thickness of 0.7 mm had a high fracture resistance and the lowest stress values. Therefore, dentists and laboratory technicians should carefully choose the optimum thickness of zirconia prostheses.
Zirconia prostheses with a minimal thickness of 0.7 mm had a high fracture resistance and the lowest stress values. Therefore, dentists and laboratory technicians should carefully choose the optimum thickness of zirconia prostheses.
Durability of the bond between different core materials and zirconia retainers is an important predictor of the success of a dental prosthesis. Nevertheless, because of its polycrystalline structure, zirconia cannot be etched and bonded to a conventional resin cement.
The purpose of this in vitro study was to compare the effects of 3 metal primer/resin cement systems on the shear bond strength (SBS) of 3 core materials bonded to yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic retainers.
Zirconia ceramic (Cercon) disks (5×3 mm) were airborne-particle abraded, rinsed, and air-dried. Disk-shaped core specimens (7×7 mm) that were prepared of composite resin, Ni-Cr, and zirconia were bonded to the zirconia ceramic disks by using one of 3 metal primer/cement systems (Z-Prime Plus/BisCem, Zirconia Primer/Multilink Automix, or Clearfil Ceramic Primer/Clearfil SA). SBS was tested in a universal testing machine. Stereomicroscopy was used to evaluate the failure mode of debonded specimens. Dahe Clearfil SA/Clearfil Ceramic Primer system, based on methacryloyloxydecyl dihydrogen phosphate (MDP), increased the bond strength of Y-TZP ceramics to core materials.
Use of the Clearfil SA/Clearfil Ceramic Primer system, based on methacryloyloxydecyl dihydrogen phosphate (MDP), increased the bond strength of Y-TZP ceramics to core materials.The problem of small oral aperture is big. Irrespective of the etiology, this problem may be overcome by adjunctive therapies in the form of prosthesis, surgery, or exercise. A patient is described with this problem, which was overcome by revisiting the 3 adjunctive therapies including a commissural stent designed with the patient’s edentulous state in mind.
Many color specification systems and color differences have been proposed to improve the correlation between color measurement and visual perception. Although color differences can be quantified using either the CIELab formula (ΔE*(ab)) or the recently introduced CIEDE2000 formula (ΔE00), which captures the perceived color difference better is unknown.
The purpose of this study was to evaluate the CIELab and CIEDE2000 formulas to determine which best reflects the difference in color perception and whether color perception differs by sex.
Forty participants grouped 18 dental resin disks (color range from 73.6 to 87.5 for L*; from -1.6 to 3.4 for a*; from 18.1 to 36.6 for b*), the only requirement being that each group was formed of disks with chromatically indistinguishable colors. Each participant was free to choose the number and composition of the groups. With the results obtained, a dissimilarity matrix was generated, and nonmetric multidimensional scaling (MDS) was applied to it to obtain the coordies perceived by the human eye better than the CIELab formula (ΔE*ab). In addition, women were confirmed to be more sensitive than men to color differences.
Scientific evidence is lacking regarding the clinical effectiveness of digital complete removable dental prostheses (CRDP).
This prospective clinical study was conducted to compare clinical treatment outcomes, patient satisfaction, and dental student preferences for digitally and conventionally processed CRDP in a predoctoral setting.
This clinical study rated and compared CRDP fabricated by predoctoral students, using a 2-appointment digital prosthesis fabrication process as opposed to the conventional 5-appointment process. Fifteen completely edentulous patients were treated in the predoctoral clinic at Loma Linda University School of Dentistry. Fifteen predoctoral (third- and fourth-year) dental students fabricated 2 sets of maxillary and mandibular CRDP for each patient. Each patient received 1 conventional set and 1 digital (AvaDent) set of CRDP. Faculty and patient ratings, patient and student preferences, and perceptions of the conventional versus digital prostheses were recorded and analyzed. Thas preferred and effectively used by predoctoral dental students under faculty supervision.
The digital process proved to be an equally effective and more time-efficient option than the conventional process of prosthesis fabrication in the predoctoral program. The digital denture process was preferred and effectively used by predoctoral dental students under faculty supervision.
Denture base resin may be exposed to different conditions for long periods, resulting in varying degrees of staining, discoloration, and distortion.
The purpose of this in vitro study was to evaluate whether an organic-inorganic hybrid coating for base resins can improve color stability and reduce water absorption and solubility.
An organic-inorganic hybrid coating was prepared, and resin sheets made from 4 types of base resin materials were divided into an experimental group (surface coating) and a control group (without coating). The water absorption and solubility in each group were tested. The resin sheets were immersed in tea, red wine, coffee, and cola. The color change (ΔE values) of resin sheets in different soaking solutions was evaluated at 1, 7, and 28 days.
Statistical analysis showed that water absorption and solubility in the experimental group were significantly lower than in the control group (P<.05). The 4 staining solutions (tea, red wine, coffee, and cola) caused base resin discoloration in a time-dependent manner. This staining and discoloration was also influenced by the type of resin material. About 85% of ΔE values in the experimental group were significantly lower than those in the control group (P<.05). At 28 days, almost all ΔE values in the experimental group were significantly lower than those in the control group (P<.05).
The organic-inorganic hybrid coating effectively reduced the water uptake and solubility of base resins and significantly improved the color stability of the denture base.
The organic-inorganic hybrid coating effectively reduced the water uptake and solubility of base resins and significantly improved the color stability of the denture base.
Improving dental esthetics is a main objective of prosthodontic treatment. Recently, digital diagnostic waxing has been proposed as an alternative to conventional diagnostic waxing; however, the impact on esthetics has not been evaluated.
The purpose of this study was to evaluate the impact of diagnostic waxing on biometric esthetic variables and to compare the esthetic outcome achieved by digital waxing with conventional waxing.
Three biometric variables were evaluated perceived frontal proportion (PFP), width/height (WH) ratio, and symmetry. Maxillary casts of 13 patients were collected. All of them had maxillary anterior teeth that required prosthodontic treatment. Two forms of diagnostic waxing were executed conventional and digital waxing. Measurements of the esthetic variables were conducted digitally. For the PFP, a frontal image was made and the width of each tooth was measured. Subsequently, the PFP values of the lateral incisor to central incisor and of the canine to central incisor were calculated.


