OBJECTIVEThis study aims to evaluate the optical data of the different sites of the cobalt-chrome (Co-Cr) alloy abutments covered by four different all-ceramic crowns and the color difference between the crowns and target tab using a digital dental spectrophotometer.

METHODSTen Co-Cr alloy abutments were made and tried in four different groups of all-ceramic crowns, namely, Procera aluminia, Procera zirconia, Lava zirconia (Lava-Zir), and IPS E.max glass-ceramic lithium disilicate-reinforced monolithic. The color data of the cervical, body, and incisal sites of the samples were recorded and analyzed by dental spectrophotometer. The CIE L*, a*, b* values were again measured after veneering. The color difference between the abutments covered by all-ceramic crowns and A2 dentine shade tab was evaluated.

RESULTSThe L* and b* values of the abutments can be increased by all of the four groups of all-ceramic copings, but a* values were decreased in most groups. A statistical difference was observed among four groups. After being veneered, the L* values of all the copings declined slightly, and the values of a*, b* increased significantly. When compared with A2 dentine shade tab, the ΔE of the crowns was below 4.

CONCLUSIONFour ceramic copings were demonstrated to promote the lightness and hue of the alloy abutments effecttively. Though the colorimetric baseline of these copings was uneven, veneer porcelain can efficiently decrease the color difference between the samples and thee target.

Ceramics ; Chromium Alloys ; Cobalt ; Color ; Colorimetry ; Crowns ; Dental Materials ; Dental Porcelain ; Dental Prosthesis Design ; Humans ; Metal Ceramic Alloys ; Titanium ; Zirconium

PURPOSE: The purpose of this study was to evaluate cell toxicity due to ion release caused by galvanic corrosion as a result of contact between base metal and titanium. MATERIALS AND METHODS: It was hypothesized that Nickel (Ni)-Chromium (Cr) alloys with different compositions possess different corrosion resistances when contacted with titanium abutment, and therefore in this study, specimens (10 x 10 x 1.5 mm) were fabricated using commercial pure titanium and 3 different types of Ni-Cr alloys (T3, Tilite, Bella bond plus) commonly used for metal ceramic restorations. The specimens were divided into 6 groups according to the composition of Ni-Cr alloy and contact with titanium. The experimental groups were in direct contact with titanium and the control groups were not. After the samples were immersed in the culture medium - Dulbecco's modified Eagle's medium[DMEM] for 48 hours, the released metal ions were detected using inductively coupled plasma mass spectrometer (ICP-MS) and analyzed by the Kruskal-Wallis and Mann-Whitney test (P<.05). Mouse L-929 fibroblast cells were used for cell toxicity evaluation. The cell toxicity of specimens was measured by the 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyltetrazolium bromide (MTT) test. Results of MTT assay were statistically analyzed by the two-way ANOVA test (P<.05). Post-hoc multiple comparisons were conducted using Tukey's tests. RESULTS: The amount of metal ions released by galvanic corrosion due to contact between the base metal alloy and titanium was increased in all of the specimens. In the cytotoxicity test, the two-way ANOVA showed a significant effect of the alloy type and galvanic corrosion for cytotoxicity (P<.001). The relative cell growth rate (RGR) was decreased further on the groups in contact with titanium (P<.05). CONCLUSION: The release of metal ions was increased by galvanic corrosion due to contact between base metal and titanium, and it can cause adverse effects on the tissue around the implant by inducing cytotoxicity.
Alloys ; Animals ; Corrosion* ; Dental Alloys ; Fibroblasts ; Ions ; Metal Ceramic Alloys ; Mice ; Nickel ; Plasma ; Titanium*

PURPOSE: The purpose of this study was to evaluate cell toxicity due to ion release caused by galvanic corrosion as a result of contact between base metal and titanium. MATERIALS AND METHODS: It was hypothesized that Nickel (Ni)-Chromium (Cr) alloys with different compositions possess different corrosion resistances when contacted with titanium abutment, and therefore in this study, specimens (10 x 10 x 1.5 mm) were fabricated using commercial pure titanium and 3 different types of Ni-Cr alloys (T3, Tilite, Bella bond plus) commonly used for metal ceramic restorations. The specimens were divided into 6 groups according to the composition of Ni-Cr alloy and contact with titanium. The experimental groups were in direct contact with titanium and the control groups were not. After the samples were immersed in the culture medium - Dulbecco's modified Eagle's medium[DMEM] for 48 hours, the released metal ions were detected using inductively coupled plasma mass spectrometer (ICP-MS) and analyzed by the Kruskal-Wallis and Mann-Whitney test (P<.05). Mouse L-929 fibroblast cells were used for cell toxicity evaluation. The cell toxicity of specimens was measured by the 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyltetrazolium bromide (MTT) test. Results of MTT assay were statistically analyzed by the two-way ANOVA test (P<.05). Post-hoc multiple comparisons were conducted using Tukey's tests. RESULTS: The amount of metal ions released by galvanic corrosion due to contact between the base metal alloy and titanium was increased in all of the specimens. In the cytotoxicity test, the two-way ANOVA showed a significant effect of the alloy type and galvanic corrosion for cytotoxicity (P<.001). The relative cell growth rate (RGR) was decreased further on the groups in contact with titanium (P<.05). CONCLUSION: The release of metal ions was increased by galvanic corrosion due to contact between base metal and titanium, and it can cause adverse effects on the tissue around the implant by inducing cytotoxicity.
Alloys ; Animals ; Corrosion* ; Dental Alloys ; Fibroblasts ; Ions ; Metal Ceramic Alloys ; Mice ; Nickel ; Plasma ; Titanium*

Oral lichen planus (OLP) is a common mucocutaneous disease, which presents as bilateral or multiple lesions. The several factors are implicated in etiology of OLP such as dental restorations, systemic disease, drugs and stress. Especially the influence of dental restorations and plaque control for OLP has been the interest in dentistry. This case is about OLP patient having poor contoured and ill-fitting metal ceramic restorations. The patient in this study has suffered from OLP for a long time, particularly after restoration of metal ceramic restorations on both posterior teeth of maxilla and mandible. This study reported that OLP lesion recovered effectively by improving the contour and fitness of restorations with plaque control.
Dentistry ; Humans ; Lichen Planus, Oral* ; Mandible ; Maxilla ; Metal Ceramic Alloys ; Oral Hygiene ; Tooth

OBJECTIVETo compare the shear bond strength(SBS) of cast Co-Cr alloys and selective laser melting(SLM) Co-Cr alloys with those of dental porcelain.

METHODSA dental porcelain (Vita) was applied on cast and SLM Co-Cr alloy specimens (n = 10). SBS test was conducted, and fracture mode analysis was determined. Student's t-test by SPSS 13.0 software was employed to analyze the data.

RESULTSThe SLM Co-Cr alloy specimens had lower SBS values than the cast Co-Cr alloy specimens (P > 0.05). The metal-porcelain bond strength value of the cast group was (33.11 +/- 4.98) MPa, and that of the SLM group was (30.94 +/- 5.98) MPa. The specimens in both test groups exhibited mixed failure.

CONCLUSIONThe metal-porcelain system processed by SLM exhibit a bond strength that is similar to that of the cast group. This system also display a high precision.

Alloys ; Chromium Alloys ; Dental Alloys ; Dental Porcelain ; Lasers ; Materials Testing ; Metal Ceramic Alloys ; Metals

PURPOSE: The porcelain fused to gold has been widely used as a restoration both with the natural esthetics of the porcelain and durability and marginal fit of metal casting. However, recently, due to the continuous rise in the price of gold, an interest towards materials to replace gold alloy is getting higher. This study compared the bond strength of porcelain to millingable palladium-silver (Pd-Ag) alloy, with that of 3 conventionally used metal-ceramic alloys. MATERIALS AND METHODS: Four types of metal-ceramic alloys, castable nonprecious nickel-chrome alloy, castable precious metal alloys containing 83% and 32% of gold, and millingable Pd-Ag alloy were used to make metal specimens (n=40). And porcelain was applied on the center area of metal specimen. Three-point bending test was performed with universal testing machine. The bond strength data were analyzed with a one-way ANOVA and post hoc Scheffe's tests (alpha=.05). RESULTS: The 3-point bending test showed the strongest (40.42 +/- 5.72 MPa) metal-ceramic bond in the nonprecious Ni-Cr alloy, followed by millingable Pd-Ag alloy (37.71 +/- 2.46 MPa), precious metal alloy containing 83% of gold (35.89 +/- 1.93 MPa), and precious metal alloy containing 32% of gold (34.59 +/- 2.63 MPa). Nonprecious Ni-Cr alloy and precious metal alloy containing 32% of gold showed significant difference (P<.05). CONCLUSION: The type of metal-ceramic alloys affects the bond strength of porcelain. Every metal-ceramic alloy used in this study showed clinically applicable bond strength with porcelain (25 MPa).
Alloys* ; Dental Porcelain* ; Esthetics ; Metal Ceramic Alloys

The case report describes the occlusal rehabilitation of a male patient with Angle Class III malocclusion and its effect on maximum bite force. The main complaints of patient were masticatory difficulty and poor esthetic. The patient's expectations from the treatment were a good esthetic and function with a less invasive and relatively promptly way. Therefore, increasing of the occlusal vertical dimension (OVD) and then restoring the maxillary and mandibular teeth was chosen by the patient among the treatment options. At the beginning of treatment maximum bite force of patient was measured. Then an occlusal splint was provided to evaluate the adaptation of the patient to the altered OVD. Full mouth rehabilitation with metal ceramic restorations was made. After the completion of full mouth restoration, bite force measurement was repeated and patient exhibited increased maximum bite force. Full mouth restorative treatment in a patient with Class III malocclusion could be an effective treatment approach to resolve esthetic concern and to improve masticatory function related to maximum bite force.
Bite Force ; Humans ; Male ; Malocclusion ; Malocclusion, Angle Class III ; Metal Ceramic Alloys ; Mouth ; Mouth Rehabilitation ; Occlusal Splints ; Tooth ; Vertical Dimension

PURPOSE: The aim of the study was to evaluate the effect of annealing on the nanostructure and hardness of Co-Cr metal ceramic samples that were fabricated with a direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS: Five groups of Co-Cr dental alloy samples were manufactured in a rectangular form measuring 4 x 2 x 2 mm. Samples fabricated by a conventional casting technique (Group I) and prefabricated milling blanks (Group II) were examined as conventional technique groups. The DMLS samples were randomly divided into three groups as not annealed (Group III), annealed in argon atmosphere (Group IV), or annealed in oxygen atmosphere (Group V). The nanostructure was examined with the small-angle X-ray scattering method. The Rockwell hardness test was used to measure the hardness changes in each group, and the means and standard deviations were statistically analyzed by one-way ANOVA for comparison of continuous variables and Tukey's HSD test was used for post hoc analysis. P values of <.05 were accepted as statistically significant. RESULTS: The general nanostructures of the samples were composed of small spherical entities stacked atop one another in dendritic form. All groups also displayed different hardness values depending on the manufacturing technique. The annealing procedure and environment directly affected both the nanostructure and hardness of the Co-Cr alloy. Group III exhibited a non-homogeneous structure and increased hardness (48.16 +/- 3.02 HRC) because the annealing process was incomplete and the inner stress was not relieved. Annealing in argon atmosphere of Group IV not only relieved the inner stresses but also decreased the hardness (27.40 +/- 3.98 HRC). The results of fitting function presented that Group IV was the most homogeneous product as the minimum bilayer thickness was measured (7.11 A). CONCLUSION: After the manufacturing with DMLS technique, annealing in argon atmosphere is an essential process for Co-Cr metal ceramic substructures. The dentists should be familiar with the materials that are used in clinic for prosthodontics treatments.
Alloys ; Argon ; Atmosphere ; Ceramics ; Dental Alloys* ; Dentists ; Electron Probe Microanalysis ; Hardness Tests ; Hardness* ; Humans ; Metal Ceramic Alloys ; Nanostructures* ; Oxygen ; Prosthodontics

OBJECTIVETo investigate the influences of recasting on the mechanical properties of Au-Pt ceramic alloy.

METHODSAu-Pt ceramic alloy samples were prepared and recast for 3 times without adding any new Au-Pt ceramic alloy. The tensile strength, 0.2% yield strength, percentage of elongation, flexural strength, flexural modulus and Vickers hardness of each specimen were measured.

RESULTSBeing cast for different times, the Au-Pt ceramic alloy showed no significant differences on their tensile strength, 0.2% yield strength, percentage of elongation, flexural strength or Vickers hardness. The flexural modulus of the Au-Pt alloys being cast for 2 or 3 times was significantly higher than that of the alloys being cast for 1 time (P < 0.05). CONCLUSION Au-Pt ceramic alloy can be recast for 3 times at least, without any decrease in the mechanical properties.

Alloys ; Ceramics ; Dental Alloys ; Gold Alloys ; Hardness ; Materials Testing ; Metal Ceramic Alloys ; Tensile Strength

This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients (TECs), when zirconia ceramics were coloured at green stage. Zirconia blocks (N=240; 6 mm×7 mm×7 mm) were manufactured from two materials namely, ICE Zirconia (Group 1) and Prettau Zirconia (Group 2). In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid (shade A2). Three different veneering ceramics with different TEC (ICE Ceramic, GC Initial Zr and IPS e.max Ceram) were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys (Esteticor Plus) veneered with ceramic (VM 13) (n=16) acted as the control group. Core-veneer interface of the specimens were subjected to shear force in the Universal Testing Machine (0.5 mm⋅min(-1)). Neither the zirconia core material (P=0.318) nor colouring (P=0.188) significantly affected the results (three-way analysis of variance, Tukey's test). But the results were significantly affected by the veneering ceramic (P=0.000). Control group exhibited significantly higher mean bond strength values (45.7±8) MPa than all other tested groups ((27.1±4.1)-(39.7±4.7) and (27.4±5.6)-(35.9±4.7) MPa with and without colouring, respectively) (P<0.001). While in zirconia-veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering <1/3 of the substrate surface, in the metal-ceramic group, veneering ceramic was left adhered >1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core-veneer adhesion. Metal-ceramic adhesion was more reliable than all zirconia-veneer ceramics tested.
Adhesiveness ; Ceramics ; chemistry ; Color ; Dental Bonding ; Dental Materials ; chemistry ; Dental Porcelain ; chemistry ; Dental Stress Analysis ; instrumentation ; Dental Veneers ; Gold Alloys ; chemistry ; Humans ; Materials Testing ; Metal Ceramic Alloys ; chemistry ; Prosthesis Coloring ; Stress, Mechanical ; Surface Properties ; Thermodynamics ; Yttrium ; chemistry ; Zirconium ; chemistry