PURPOSE: To evaluate and compare the effect of different materials and techniques on the shear bond strength of veneering ceramic materials to zirconia. MATERIALS AND METHODS: 136 sintered zirconia cubes were prepared and randomly divided into four study groups according to corresponding methods of surface treatment and materials: GLN (grinding followed by laser scanning using Noritake Cerabien ZR), SLN (sandblasting followed by laser scanning using Noritake Cerabien ZR), GLV (grinding followed by laser scanning using VITA VM 9), and SLV (sandblasting followed by laser scanning using VITA VM 9). Spraying technique was performed to coat the core. Profilometer, SEM, XRD, EDS, universal testing machine, and stereomicroscope were used to record surface roughness Ra, surface morphology, phase transformation, elemental compositions, shear bond strength SBS values, and failure types, respectively. Specimens were investigated in unaged (not immersed in artificial saliva) and aged (stored in artificial saliva for a month) conditions to evaluate SBS values. RESULTS: Grinding and GLN as first and second surface treatments provided satisfactory Ra values in both conditions (1.05 ± 0.24 µm, 1.30 ± 0.21 µm) compared to sandblasting and other groups (P < .05). The group GLN showed the highest SBS values in both conditions (30.97 ± 3.12 MPa, 29.09 ± 4.17 MPa), while group SLV recorded the lowest (23.96 ± 3.60 MPa, 22.95 ± 3.68 Mpa) (P < .05). Sandblasting showed phase transformation from t-m. Mixed failure type was the commonest among all groups. CONCLUSION: GLN showed to be a reliable method which provided satisfactory bond strength between the veneer ceramic and zirconia. This method might preserve the integrity of fixed dental crowns.
Ceramics ; Crowns ; Methods ; Saliva, Artificial

BACKGROUND: The market for vitamin drinks is expanding both in Korea and worldwide. However, it was difficult to find studies regarding the possibility of tooth erosion induction due to vitamin drinks. The purpose of the present in vitro study was to evaluate the effect of tooth erosion caused by a few commercial vitamin beverages on bovine teeth enamel in terms of erosion depth and fluorescence loss. METHODS: Three experimental groups (vitamin drinks), a positive control group (Coca-Cola), and a negative control group (mineral water) were established. Each group consisted of 5 specimens obtained from sound bovine teeth. The pH and titratable acidity of beverages were measured. Specimens were immersed in the beverages and artificial saliva for 6 and 18 hours, respectively. This cycle was repeated for 5 days. The depth of the tooth loss caused by tooth erosion (erosion depth) and maximum loss of fluorescence (Max ΔF) were measured using the microscope and quantified light-induced fluorescence-digital, respectively. For the statistical analysis, the Kruskal-Wallis test and ANOVA were used to compare the erosion depth and Max ΔF of the enamel surfaces. In addition, Spearman correlations were estimated. RESULTS: The pH of the three vitamin beverages ranged from 2.65 to 3.01, which is similar to that of the positive control group. All beverages, except mineral water, had sugar and acidic ingredients. Vitamin drinks and the positive control, Coca-Cola, caused tooth erosion lesions, and showed significant differences in erosion depth compared to mineral water (p<0.05). The vitamin beverages with low pH were associated with high erosion depth and Max ΔF. CONCLUSION: Vitamin drinks have the potential to cause tooth erosion.
Beverages ; Dental Enamel ; Fluorescence ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Korea ; Mineral Waters ; Saliva, Artificial ; Tooth Erosion ; Tooth Loss ; Tooth ; Vitamins

The purpose of this study was to examine effects of bioactive glass on Vickers hardness of bleached enamel surface. Enamel specimens were bleached with 15% carbamide peroxide (CP) for 14days. After bleaching, Artificial saliva (AS), 45S5 bioactive glass (BAG) and fluoride varnish (FV) are applied each specimens (n=10). The Vickers hardness of the specimens was measured before and after the bleaching, after the remineralized treatment at 1 day and after 7 and 14 days. The Vickers hardness on enamel surface after bleaching decreased statistically (p < 0.05) compared to before bleached enamel surface. The Vickers hardness increased significantly in the BAG and FV groups compared to the AS group values at 1 day and 7 days after remineralization (P < 0.05). 45S5 bioactive glass rapidly increase Vickers hardness of the bleached enamel surface.
Dental Enamel ; Fluorides ; Glass ; Hardness ; Paint ; Saliva, Artificial ; Urea

To explore the remineralization effect of bioactive glass NovaMin on demineralized dentin specimens, and to study the physical and chemical properties of formed structure at dentin surface.
 Methods: One mm-thickness coronal dentin slices were soaked in ethylene diamine tetraacetic acid (EDTA) for 48 h to prepare the completely demineralized dentin specimens and they were divided into 2 groups: an artificial saliva group (control group) and a NovaMin powder group. The specimens were treated with artificial saliva or NovaMin powder for 2 min (2 times every day), and the interval was 8 hours. Then, the specimens were soaked in the remineralization solution. After 7 days, the scanning electron microscope (SEM), energy dispersive X-ray (EDX), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD) were used to detect dentin morphology, the physical and chemical properties of the formed structure at dentin surface.
 Results: The results of SEM showed that a defined surface layer in the NovaMin powder group could be observed in the SEM imaging at the 7th day, which completely occluded dentinal tubules; the EDX, ATR-FTIR and XRD analysis found that the mineralized layer formed at dentin surface was mainly composed of calcium and phosphate elements, which was similar to the hydroxyapatite-like crystal. However, there were no materials formed at the dentin surface in the control group, and the dentinal tubules were still open.
 Conclusion: NovaMin can remineralize the demineralized dentin specimens and occlude the dentinal tubules in hydroxyapatite-like crystal structure.
Dental Pulp Cavity ; Dentin ; chemistry ; Glass ; Microscopy, Electron, Scanning ; Saliva, Artificial ; Spectroscopy, Fourier Transform Infrared ; Tooth Remineralization ; methods

OBJECTIVES: The purpose of this study was to evaluate the effect of a dentifrice containing 1,500 ppm F (NaF) and 2% bamboo salt on dental erosion caused by ingestion of acidic beverages. METHODS: Specimens of extracted bovine teeth enamel were embedded in a resin and polished. Experimental specimens were subjected to one of the six treatments (n=10 per treatment group): the experimental group consisted of 1,500 ppm F (NaF)+2% bamboo salt; 1,500 ppm F (NaF); 1,000 ppm F (NaF)+2% bamboo salt; 1,000 ppm F (NaF); free fluoride+2% bamboo salt; and free fluoride. The specimens were exposed to the experimental dentifrice, an acidic beverage, and artificial saliva. The treated specimens were analyzed using a Vickers surface hardness test and scanning electron microscopy (SEM). Surface hardness and SEM were compared before and after the chemical pH cycling sequences for 12 days. RESULTS: Group 1 (1,500 ppm F+2% bamboo salt) showed the highest surface hardness, followed by group 2 (1,500 ppm F), group 3 (1,000 ppm F+2% bamboo salt), group 4 (1,000 ppm F), group 5 (free fluoride+2% bamboo salt), and group 6 (free fluoride), in that order. Upon observing the surface by SEM, when bamboo salt was used and when the NaF concentration was higher, the enamel was denser and the surface was more highly remineralized. CONCLUSIONS: The use of a higher concentration of NaF and bamboo salt resulted in a higher preventive effect on tooth erosive potential. The addition of bamboo salt to dentifrice containing a high concentration of NaF can contribute to preventing dental erosion.
Beverages ; Dental Enamel ; Dentifrices* ; Eating ; Fluorides ; Hardness ; Hardness Tests ; Hydrogen-Ion Concentration ; Microscopy, Electron, Scanning ; Saliva, Artificial ; Tooth

PURPOSE: The purpose of this study was to analyze the retention force changes and wear behaviours of double-crown systems over long-term use. MATERIALS AND METHODS: Ten groups, each consisting of six samples, were evaluated. Specifically, casting gold alloy primary crown - casting gold alloy secondary crown (AA), laser sintering primary crown - laser sintering secondary crown (LL), casting Cr alloy primary crown - casting Cr alloy secondary crown, (CC) zirconia primary crown - electroformed secondary crown (ZA), and CAD/CAM titanium alloy primary crown - CAD/CAM titanium alloy secondary crown (TT) groups were evaluated at cone angles of 4° and 6°. The samples were subjected to 5,000 insertion-separation cycles in artificial saliva, and the retention forces were measured every 500 cycles. The wear levels were analyzed via SEM at the beginning and end of the 5,000 cycles. RESULTS: In all samples, the retention forces increased when the conus angle decreased. The highest initial and final retention force values were found in the LL-4° group (32.89 N-32.65 N), and the lowest retention force values were found in the ZA6° group (5.41 N-6.27 N). The ZA groups' samples showed the least change in the retention force, and no wear was observed. In the other groups, wear was observed mostly in the primary crowns. CONCLUSION: More predictable, clinically relevant, and less excursive retention forces can be observed in the ZA groups. The retention force values of the LL groups were statically similar to those of the other groups, except the ZA groups.
Alloys ; Conus Snail ; Crowns* ; Methods* ; Saliva, Artificial ; Titanium

OBJECTIVES: The purpose of this study was to compare enamel remineralization effects of human whole saliva and currently available artificial saliva compositions, using teeth exposed to chemical pH cycling conditions, and to obtain data that can inform future design and manufacturing of additional artificial saliva compositions. METHODS: Seventy-two specimens of bovine tooth enamel were embedded in resin, then polished and exposed to a lactate/carbopol buffer system for 48-52 hours. Specimens were allocated into six experimental groups (n=12 specimens per group) by randomized blocks, such that each group contained an equivalent proportion of specimens at each Vickers hardness number (VHN) stratum: deionized water as a negative control, human whole saliva and artificial saliva compositions A, B, C and D. Surface hardness was measured before and after 15 days of chemical pH cycling. Surface microhardness was measured (Fm-7, Future-tech Corp, Japan) before and after treatment with test saliva compositions. One-way ANOVA, with post hoc Tukey test, was used to evaluate statistical differences with a significance threshold of P<0.05. RESULTS: The intragroup changes in microhardness (ΔVHN) for treatment with each saliva composition were (in ascending order of ΔVHN): ―0.39±16.08 (deionized water control), 7.32±11.52 (artificial saliva B), 39.18±11.94 (artificial saliva C), 3.83±13.81 (artificial saliva D), 62.44±29.23 (artificial saliva A) and 102.90±25.89 (human whole saliva). Enamel treated with human saliva, or with artificial saliva compositions A, C, or D, demonstrated comparatively greater microhardness than enamel treated with deionized water or artificial saliva B. There was no difference in surface hardness between enamel treated with artificial saliva B and enamel treated with deionized water. CONCLUSIONS: Our study suggests that human saliva and artificial saliva compositions A, C, and D are effective remineralization solutions for use in pH cycling.
Dental Caries* ; Dental Enamel ; Hardness ; Humans* ; Hydrogen-Ion Concentration ; Saliva ; Saliva, Artificial* ; Tooth ; Water

OBJECTIVE: We evaluated the effects of tooth displacement on frictional force when conventional ligating lingual brackets (CL-LBs), CL-LBs with a narrow bracket width, and self-ligating lingual brackets (SL-LBs) were used with initial leveling and alignment wires. METHODS: CL-LBs (7th Generation), CL-LBs with a narrow bracket width (STb), and SL-LBs (In-Ovation L) were tested under three tooth displacement conditions: no displacement (control); a 2-mm palatal displacement (PD) of the maxillary right lateral incisor (MXLI); and a 2-mm gingival displacement (GD) of the maxillary right canine (MXC) (nine groups, n = 7 per group). A stereolithographic typodont system and artificial saliva were used. Static and kinetic frictional forces (SFF and KFF, respectively) were measured while drawing a 0.013-inch copper-nickel-titanium archwire through brackets at 0.5 mm/min for 5 minutes at 36.5℃. RESULTS: The In-Ovation L exhibited lower SFF under control conditions and lower KFF under all displacement conditions than the 7th Generation and STb (all p < 0.001). No significant difference in SFF existed between the In-Ovation L and STb for a 2-mm GD of the MXC and 2-mm PD of the MXLI. A 2-mm GD of the MXC produced higher SFF and KFF than a 2-mm PD of the MXLI in all brackets (all p < 0.001). CONCLUSIONS: CL-LBs with narrow bracket widths exhibited higher KFF than SL-LBs under tooth displacement conditions. CL-LBs and ligation methods should be developed to produce SFF and KFF as low as those in SL-LBs during the initial and leveling stage.
Friction* ; Incisor ; Ligation ; Saliva, Artificial ; Tooth*

OBJECTIVES: We compared the effects of a 1,500 ppm fluoride-containing toothpaste and a 1,000 ppm fluoride-containing toothpaste, which were revised up to the recent revision, and evaluated their effects on the tooth surface after adding bamboo salt to the preparations. METHODS: Experimental early artificial caries specimens were subjected to one of four treatments (n=12 per treatment group): 1,500 ppm NaF, 2% bamboo salt+1,000 ppm NaF, 1,000 ppm NaF, and control treatment. The specimens were exposed to the experimental toothpaste, artificial saliva, and demineralized solution. The treated specimens were analyzed using Vickers surface hardness testing, scanning electron microscopy, and atomic force microscopy. RESULTS: The toothpaste with a high fluoride concentration (1,500 ppm NaF) showed more remineralization than did the toothpaste with a low fluoride concentration (1,000 ppm NaF). The 2% bamboo salt+1,000 ppm NaF group showed remineralization similar to the 1,500 ppm NaF group and higher surface microhardness than the 1,000 ppm NaF group. CONCLUSIONS: Toothpastes containing 1,500 ppm NaF have a higher preventive effect against dental caries than do toothpastes containing 1,000 ppm NaF. The addition of bamboo salt to fluoride-containing dentifrices improves their effectiveness in preventing dental caries.
Dental Caries ; Dental Enamel* ; Dentifrices ; Fluorides ; Hardness Tests ; Microscopy, Atomic Force ; Microscopy, Electron, Scanning ; Saliva, Artificial ; Tooth ; Toothpastes*

OBJECTIVEThis study aims to determine the effect of fluoride concentration on the corrosion behavior of cobalt-chromium alloy fabricated by two different technology processes in a simulated oral environment.

METHODSA total of 15 specimens were employed with selective laser melting (SLM) and another 15 for traditional casting (Cast) in cobalt-chromium alloy powders and blocks with the same material composition. The corrosion behavior of the specimens was studied by potentiodynamic polarization test under different oral environments with varying solubilities of fluorine (0, 0.05%, and 0.20% for each) in acid artificial saliva (pH = 5.0). The specimens were soaked in fluorine for 24 h, and the surface microstructure was observed under a field emission scanning electron microscope after immersing the specimens in the test solution at constant temperature.

RESULTSThe corrosion potential (Ecorr) value of the cobalt-chromium alloy cast decreased with increasing fluoride concentration in acidic artificial saliva. The Ecorr, Icorr, and Rp values of the cobalt-chromium alloy fabricated by two different technology processes changed significantly when the fluoride concentration was 0.20% (P < 0.05). The Ecorr, Icorr, and Rp values of the cobalt-chromium alloy fabricated by two different technology processes exhibited a statistically significant difference. The Icorr value of the cobalt-chromium alloy cast was higher than that in the SLM group cobalt-chromium alloy when the fluoride concentration was 0.20% (P < 0.05). The Ecorr, tRp alues of the cobalt-chromium alloy cast were lower htan those of the SLM group cobalt-chromium alloy when the fluoride concentration was 0.20% (P< 0 .05).

CONCLUSIONFluoride ions adversely affected the corrosion resistance of the cobalt-chromium alloy fabricated by two different technology processes. The corrosion resistance of the cobalt-chromium alloy cast was worse than that of the SLM group cobalt-chromium alloy when the fluoride concentration was 0.20%.