PURPOSE: This study aimed to evaluate the effect of pretreatment of three different universal adhesives (Single Bond Universal [SBU], All-Bond Universal [ABU], and Prime&Bond universal [PBU]) on the bonding durability of an adhesive (Panavia F 2.0, PF) and a conventional (Duo-Link, DL) resin cements to air-abraded zirconia. MATERIALS AND METHODS: Rectangular-shaped zirconia specimens were prepared. The chemical composition and surface energy parameters of the materials were studied by Fourier transform infrared spectroscopy and contact angle measurement, respectively. To evaluate resin bonding to the zirconia, all the bonding specimens were immersed in water for 24 h and the specimens to be aged were additionally thermocycled 10000 times before the shear bond strength (SBS) test. RESULTS: The materials showed different surface energy parameters, including the degree of hydrophilicity/hydrophobicity. While the DL/CON (no pretreatment) showed the lowest SBS and a significant decrease in the value after thermocycling (P < .001), the PF/CON obtained a higher SBS value than the DL/CON (P < .001) and no decrease even after thermocycling (P = .839). When the universal adhesives were used with DL, their SBS values were higher than the CON (P < .05), but the trend was adhesive-specific. In conjunction with PF, the PF/SBU produced the highest SBS followed by the PF/ABU (P = .002), showing no significant decrease after thermocycling (P > .05). The initial SBS of the PF/PBU was similar to the PF/CON (P = .999), but the value decreased after thermocycling (P < .001). CONCLUSION The universal adhesive pretreatment did not necessarily show a synergistic effect on the bonding performance of an adhesive resin cement, whereas the pretreatment was beneficial to bond strength and durability of a conventional resin cement.

Very virulent infectious bursal disease virus (vvIBDV) causes high mortality in chickens but measures to reduce the mortality have not been explored. Chickens (8–9 weeks) were treated with 3 agents before and during vvIBDV inoculation. Dexamethasone treatment reduced the mortality of infected chickens (40.7% vs. 3.7%; p < 0.001), but treatment with aspirin or vitamin E plus selenium did not affect the mortality. The bursa of Fabricius appeared to have shrunk in both dead and surviving chickens (p < 0.01). The results indicate that dexamethasone can reduce mortality in vvIBDV-infected chickens and may provide therapeutic clues for saving individual birds infected by the virus.

Very virulent infectious bursal disease virus (vvIBDV) causes high mortality in chickens but measures to reduce the mortality have not been explored. Chickens (8–9 weeks) were treated with 3 agents before and during vvIBDV inoculation. Dexamethasone treatment reduced the mortality of infected chickens (40.7% vs. 3.7%; p < 0.001), but treatment with aspirin or vitamin E plus selenium did not affect the mortality. The bursa of Fabricius appeared to have shrunk in both dead and surviving chickens (p < 0.01). The results indicate that dexamethasone can reduce mortality in vvIBDV-infected chickens and may provide therapeutic clues for saving individual birds infected by the virus.

This study aimed to investigate whether pre-curing the universal adhesives affect the resin bonding to zirconia ceramic. Two commercial universal adhesives (All-Bond Universal, ABU; Single Bond Universal Adhesive, SBU) were tested in comparison with a conventional zirconia primer (Z-Prime Plus, ZPP). Air-abraded zirconia specimens were divided into six groups, to which different priming agents were applied with or without photo-polymerization. After resin cylinders were built on the primed zirconia surface using a resin cement (Duo-Link), all bonded specimens were stored in water at 37℃ for 24 hours and half of them (n = 12) were additionally thermocycled 5,000 times. A shear bond strength test was performed at a crosshead speed of 0.5 mm/minute and failure modes were assessed using an optical microscope at 25× magnification. Before thermocycling, the light-cured specimens of ABU and SBU showed higher bond strengths than the uncured ones of the materials (p<0.05), whereas no significant difference was found between the pre-cured and uncured specimens of ZPP (p > 0.05). After thermal aging, there were significant decreases in the bond strength for all specimens treated with the universal adhesives (p<0.05). However, ZPP produced no significant difference after aging (p > 0.05) and attained higher bond strength values for both the pre-cured and uncured specimens when compared to the two universal adhesives (p<0.05). Adhesive failures were predominant in all test groups and thermocycling resulted in the higher incidences of adhesive failures for the uncured groups, which was not shown in the pre-cured groups.
Adhesives ; Aging ; Ceramics ; Incidence ; Resin Cements ; Water

PURPOSE: The present study was designed to examine the clinical fit of fixed dental prosthesis fabricated by the milling-sintering method using a presintered cobalt-chromium alloy. MATERIALS AND METHODS: Two single metal-ceramic crowns were fabricated via milling-sintering method and casting method in each of the twelve consecutive patients who required an implant-supported fixed prosthesis. In the milling-sintering method, the prosthetic coping was designed in computer software, and the design was converted to a non-precious alloy coping using milling and post-sintering process. In the casting method, the conventional manual fabrication process was applied. The absolute marginal discrepancy of the prostheses was evaluated intraorally using the triple-scan technique. Statistical analysis was conducted using Mann-Whitney U test (α=.05). RESULTS: Eight patients (66.7%) showed a lower marginal discrepancy of the prostheses made using the milling-sintering method than that of the prosthesis made by the casting method. Statistically, the misfit of the prosthesis fabricated using the milling-sintering method was not significantly different from that fabricated using the casting method (P=.782). There was no tendency between the amount of marginal discrepancy and the measurement point. CONCLUSION: The overall marginal fit of prosthesis fabricated by milling-sintering using a presintered alloy was comparable to that of the prosthesis fabricated by the conventional casting method in clinical use.
Alloys ; Clinical Study ; Crowns ; Dental Prosthesis ; Humans ; Methods ; Prostheses and Implants

Sufficient bonding between the framework of the cast alloy and the denture base resin is essential for the clinical success of removable partial dentures. In this study, we investigated whether the silane and alkali treatments improve the chemical bonding between two nickel-chromium alloys and acrylic resin and thus the shear bond strength. A silane solution was prepared using 3-methacryloxypropyltrimethoxysilane. The alloy specimens were treated with silane and alkali, preparing four experimental groups: untreated (UT), silane treated (ST), alkali treated (AT), and alkali/silane treated (AST) groups. In addition, the contact angles and surface roughness of the alloy surfaces of the four groups were measured. The acrylic resin was bonded to the alloy specimens, and then the resin was polymerized to form a bonded specimen. After measuring the shear bond strength, the failure modes were examined using scanning electron microscopy. Results for all groups were analyzed using two-way ANOVA followed by Tukey's multiple comparison test at a significance level of 0.05. The statistical analysis showed no significant differences in Ra value for all groups (p>.05). In the two alloys, the contact angle of the AT group was significantly lower than that of the other groups (p<.05), and that of the AST group was significantly higher than that of the ST group (p<.05). In both alloys, the ST and AST groups showed the higher shear bond strengths (p<.05), while the UT and AT groups showed the lower values. The UT and AT groups showed complete adhesive failure at the fractured surfaces. In this study, the silane treatment was effective to improve the shear bond strength, but the alkali treatment did not show any significant effect.

BACKGROUND: Radiation therapy is widely employed in the treatment of head and neck cancer. Adverse effects of therapeutic irradiation include delayed bone healing after dental extraction or impaired bone regeneration at the irradiated bony defect. Development of a reliable experimental model may be beneficial to study tissue regeneration in the irradiated field. The current study aimed to develop a relevant animal model of post-radiation cranial bone defect. METHODS: A lead shielding block was designed for selective external irradiation of the mouse calvaria. Critical-size calvarial defect was created 2 weeks after the irradiation. The defect was filled with a collagen scaffold, with or without incorporation of bone morphogenetic protein 2 (BMP-2) (1 μg/ml). The non-irradiated mice treated with or without BMP-2-included scaffold served as control. Four weeks after the surgery, the specimens were harvested and the degree of bone formation was evaluated by histological and radiographical examinations. RESULTS: BMP-2-treated scaffold yielded significant bone regeneration in the mice calvarial defects. However, a single fraction of external irradiation was observed to eliminate the bone regeneration capacity of the BMP-2-incorporated scaffold without influencing the survival of the animals. CONCLUSION: The current study established an efficient model for post-radiation cranial bone regeneration and can be applied for evaluating the robust bone formation system using various chemokines or agents in unfavorable, demanding radiation-related bone defect models.
Animals ; Bone Morphogenetic Protein 2 ; Bone Regeneration ; Chemokines ; Collagen ; Head and Neck Neoplasms ; Mice ; Models, Animal ; Models, Theoretical ; Osteogenesis ; Regeneration ; Skull

The purpose of this study was to compare the accuracy of the working models fabricated by the subtractive and additive processing methods based on the 3-dimensional reconstruction model. A total of 20 models were fabricated with subtractive processing method from polymethyl methacrylate (PMMA) blocks using the stereolithography (STL) file of master gypsum model and another 20 models were fabricated with additive processing method using 3D printer with 0.025 mm of a layer thickness. The CAD-reference-model (CRM) and CAD-test-model (CTM) were superimposed by a software for accuracy analysis (Geomagic Qualify 13), where the STL files were transformed to point cloud data and the surface data (CRM and CTM) were subjected to initial alignment and followed by re-alignmented according to best-fit superimposition. The distances between surface data and all points, in this process, were converted to the root mean square (RMS) and averaged. In the experimental results, It was shown that the accuracy is higher in work model fabricated by additive processing method compared to one fabricated by subtractive one (p < 0.05). In addition, it is considered that the working model fabricated by subtractive processing method is to be clinically applicable by improving the improper reproducibility of the tooth surface and depressed area.
Calcium Sulfate ; Methods ; Polymethyl Methacrylate ; Printing, Three-Dimensional ; Tooth

The purpose of this study is to correlate the material properties of TiZr alloy material (Roxolid) and the mechanical strength of the implant fixture (BLT) through the maximum compressive load test and the fatigue test. Implant samples were purchased with BLT (Roxolid, Straumann, Switzerland) and Octa1 (cold-worked, Megagen Implant, Korea) fixtures made of two materials (TiZr and cold-worked Ti Grade 4). After the maximum compressive load test, the test specimens were analyzed with a optical microscope to confirm the fracture pattern. After the fatigue test, the samples that passed 5 million cycles were analyzed for the precision fit using a scanning electron microscope. Data were analyzed using Student's t-test (α=0.05). In the compressive load test, the small diameter (3.3 mm) implants with the same length and the common diameter (4.1 mm) implants had fracture or bending regardless of the material in both the test and control groups. The fatigue load showed the same results without significance and the gap between the fixture and abutment interface was within 10 µm in both the test and control groups in the precision fit test. There was no statistically significant difference in the maximum compressive load and fatigue test for the comparison of mechanical strength between two systems (BLT vs. Octa1) with same diameter and length, similar shapes and connections.
Alloys ; Fatigue

OBJECTIVES: Although the coating of surface sealants to dental composite resin may potentially reduce bacterial adhesion, there seems to be little information regarding this issue. This preliminary in vitro study investigated the adhesion of Streptococcus mutans (S. mutans) on the dental composite resins coated with three commercial surface sealants. MATERIALS AND METHODS: Composite resin (Filtek Z250) discs (8 mm in diameter, 1 mm in thickness) were fabricated in a mold covered with a Mylar strip (control). In group PoGo, the surfaces were polished with PoGo. In groups PS, OG, and FP, the surfaces polished with PoGo were coated with the corresponding surface sealants (PermaSeal, PS; OptiGuard, OG; Fortify Plus, FP). The surfaces of the materials and S. mutans cells were characterized by various methods. S. mutans adhesion to the surfaces was quantitatively evaluated using flow cytometry (n = 9). RESULTS: Group OG achieved the lowest water contact angle among all groups tested (p < 0.001). The cell surface of S. mutans tested showed hydrophobic characteristics. Group PoGo exhibited the greatest bacterial adhesion among all groups tested (p < 0.001). The sealant-coated groups showed statistically similar (groups PS and FP, p > 0.05) or significantly lower (group OG, p < 0.001) bacterial adhesion when compared with the control group. CONCLUSIONS: The application of the surface sealants significantly reduced S. mutans adhesion to the composite resin polished with the PoGo.
Bacterial Adhesion ; Composite Resins ; Flow Cytometry ; Fungi ; In Vitro Techniques* ; Streptococcus mutans* ; Streptococcus* ; Surface Properties ; Water