Silicoater MD Research Articles

Factors Affecting the Bonding of Silicoater MD System for Resin Veneering to Cp Titanium

Factors Affecting the Bonding of Silicoater MD System for Resin Veneering to Cp Titanium

Resistance of core materials against torsional forces on differently conditioned titanium posts

Statement of Problem. The separation of core materials from titanium posts, which have a low modulus of elasticity, has been identified as a problem in restorative dentistry. Purpose. This study evaluated the resistance to torsional forces of various core materials adapted to differently conditioned titanium posts. Material and Methods. Seven hundrd and twenty specimens were tested consisting of: 6 core materials and 5 surface conditioning techniques for 2 kinds of opaquers with 10 specimens in each group (6 × 5 × 2 × 10=600) plus 6 core materials and 2 opaquers were tested and considered as control groups on nonconditioned titanium posts, each group containing 10 specimens (6 × 2 × 10=120). The custom-made pure titanium posts were conditioned with the following products: Silicoater Classical, Silicoater MD, Rocatec, Kevloc, and Siloc surface-conditioning systems. Subsequently, 6 core materials with different compositions (Durafill, Adaptic, Coradent, Ti-Core, Hytac Aplitip, and Photac-Fil Aplitip) were applied to titanium posts that were previously coated with 2 types of light-polymerized opaquers, either Artglass or Dentacolor. Sixty air-abraded titanium posts (250 μm, 30 seconds) were used as controls for each core material. Following thermocycling (5°-55°C, 30 seconds, 5000 cycles), maximum torsional forces were determined with an electronic torque movement key. Data were statistically analyzed by 1-way analysis of variance followed by 2-way analysis of variance (P<.05). Results. Significantly higher mean torsional forces were observed with respect to Siloc (20.4 Newton decimeter [dNm]), Silicoater Classical (18.6 dNm), Silicoater MD (18.2 dNm), and Rocatec (17.0 dNm) systems compared with the mean for the untreated control group (14.6 dNm) (P<.001). The Kevloc system (10.4 dNm) demonstrated no significant difference compared with the control group (P>.001). The Kevloc system in combination with the Artglass opaquer and Photac-Fil Aplitip (0.00 dNm) core material showed no resistance against torsional forces. Significant differences were observed between hybrid core materials and microfilled composite, compomer, or resin-modified glass ionomer core materials (P<.001). Conclusion. Within the limitations of this study, the resistance to torsional forces for the core materials on titanium posts increased with the use of chemical surface-conditioning techniques and varied in accordance with the opaquer type. Type of core material also significantly influenced the resistance after thermocycling. (J Prosthet Dent 2002;88:367-74.)

Investigation of microleakage at the interface between a Co-Cr based alloy and four polymeric veneering materials

Statement of Problem. Marginal adaptation and resistance to microleakage are important factors for clinical success in fixed prosthodontics. Alloy corrosion that sometimes occurs under a veneer in the cervical area may result in cervical staining, a metallic taste, or even failure of the interface. Purpose. This study investigated cervical microleakage between a Co-Cr alloy and 4 indirect polymeric veneering materials used with different conditioning systems. Material and Methods. Sixteen metallic frameworks (copings) were obtained by fabricating 0.6-mm calibrated wax patterns on a master cast abutment. The wax patterns were provided with 0.4-mm beaded retention on the veneering surfaces and cast in a Co-Cr based alloy (Biosil F) used for fixed partial dentures. The Co-Cr copings were divided equally into 4 groups and veneered with 4 polymeric materials (Signum, Solidex, Superpont C+B, and Targis). Three chemical conditioning systems (Siloc, Targis-Link, and Silicoater MD) were used with the respective veneering system recommended by the manufacturer; Conolar opaque was used for Superpont C+B. No control group was created. After 2 weeks of storage in distilled water at 37°C, 2000 cycles at 5-55°C, and 24 hours of storage in 0.5% basic fuchsine, specimens were embedded in clear liquid casting resin and sectioned along a perpendicular cervical-incisal plane through the middle of the cervical collar. The surfaces of the resulting sections were examined in the cervical area with a metallurgical microscope to detect dye penetration. Leakage was quantitatively evaluated with the use of a scoring system (established by the authors) that indicated the presence/absence of dye in 3 regions of the cervical interface from the collar to the incisal margin. Scores were compared and analyzed with the use of 1-way analysis of variance followed by post-hoc Tukey's honestly significant difference test (P=.05). Results. Superpont C+B was associated with the highest microleakage scores (3.75 ± 0.5). The least microleakage at the interface was produced by Targis (1 ± 0.816), followed by Solidex (2.5 ± 1.0) and Signum (2.25 ± 0.975). Only the difference between Targis and Superpont C+B was significant (P<.05). Conclusion. Within the limitations of this in vitro study, the extent of cervical microleakage between the coping and veneer depended on the particular polymeric material used for veneering. The extremes of the study were Targis/Targis-Link (lowest leakage scores) and Superpont C+B (highest leakage scores). Differences among the chemical retention systems tested were not significant. (J Prosthet Dent 2002;87:620-4.)

Tensile bond strengths of composites to a gold-palladium alloy after thermal cycling

Statement of Problem. Many different materials and methods have been used to fabricate or repair veneer facings with composites, but only a few of these have been studied. Purpose. This study compared the tensile bond strengths of composites to a gold-palladium alloy with the use of several surface treatment methods. Material and Methods. Forty alloy specimens were cast in Eclipse (52% gold and 37.5% palladium) in the form of truncated cones. These specimens were divided equally into 4 groups. In group I, the bonding surfaces of the metal cones were treated with Silicoater MD. Truncated cones of Dentacolor composite were bonded to the metal surfaces and light-polymerized. In group II, the bonding surfaces of the metal cones were air-particle abraded with 50 μm aluminum oxide and coated with C&B Metabond. Truncated cones of Epic-TMPT composite were bonded to the metal surfaces and light-polymerized. In group III, the bonding surfaces of the metal cones were air-particle abraded with CoJet-Sand. Truncated cones of Pertac-Hybrid composite were bonded to the metal surfaces and light-polymerized. In group IV, the bonding surfaces of the metal cones were air-particle abraded with CoJet-Sand. Truncated cones of Visio-Gem were bonded to the metal surfaces and light-polymerized. After 24 hours of water immersion at 37°C and 1000 thermal cycles in water at 5°C and 55°C, tensile forces were applied to all specimens with a universal testing machine. Analysis of variance was applied to the data (P<.05), and differences among means were determined with a Tukey-Kramer interval of 5.4 MPa. Results. Tensile bond strengths in MPa were as follows: Dentacolor, 14 ± 5; Epic-TMPT, 12 ± 4; Pertac-Hybrid, 13 ± 5; and Visio-Gem, 18 ± 4. The tensile bond strength of Visio-Gem was significantly higher than that of Epic-TMPT, but no differences were found among Dentacolor, Pertac-Hybrid, and Epic-TMPT (P<.05). Conclusion. Within the limitations of this study, all 4 bonding systems tested produced high bond strengths between composites and a gold-palladium alloy after thermal cycling. (J Prosthet Dent 2002;87:271-6.)

Water resistance of resin-bonded joints with time related to alloy surface treatment

Objectives: This paper attempts to study the resistance of resin-bonded metallic joints to damage in water with time. Methods: Unlike the shear or tensile test, a cleavage test (Double Cantilever Beam test) allows us to follow the crack propagation in water, according to the fracture mechanics concept. Moreover, it is possible to follow the kinetic degradation of the metal/resin interface because this test is not totally destructive to the assembly. We have worked on 18 batches according to the nature of the alloys (Pd, Pd–Ag, Au, Co–Cr and Ni–Cr) and the surface treatment (sandblasting, Silicoater MD, Rocatec, V-Primer). The crack length was measured over a period of 20 days. The results are expressed in terms of adherence energy. Results: The adherence energy dramatically decreased with time in water. The slope of the regression straight line appears to be a good criterion for evaluating the durability of the alloy/adhesive interface. We have demonstrated the importance of silica coating and, especially, the effectiveness of the Rocatec system upon the degree of hydrolytic degradation, and have shown how the development of cracks depends upon surface treatment.

Effect of different surface preparations on the tensile strength of adhesively bonded metal joints

In this in vitro study, the effects of different surface preparations and resins on the strength and durability of adhesively bonded joints were evaluated. Disk-shaped cobalt-chromium substrate samples of the first group were treated by the Silicoater MD® system. Samples of the two subgroups were bonded with two different bisphenol-A glycidyl methacrylate (Bis-GMA) adhesives. Samples of the second group were treated by the Rocatec®) system and bonded with a Bis-GMA adhesive. Alumina-blasted samples of the third group were bonded with two different types of Bis-GMA adhesive modified with a phosphate monomer. Samples were stored in water for 3 days, or thermocycled and stored in water for 6 months. The joint samples were then tested for tensile bond strength. When the alumina-blasted samples were bonded with Panavia Ex® or Panavia 21® adhesive the highest bond strength was obtained, regardless of the storage conditions. The Silicoater MD method in combination with the Bis-GMA adhesive yielded high initial bond strengths comparable to those obtained with the Panavia systems, but also recorded the highest drops in bond strengths with both types of adhesive after thermal stressing and water storage. The Rocatec system in combination with Nimetic Grip adhesive produced a low but stable bond strength even after thermocycling and water storage.

Effect of bonded metal substrate area and its thickness on the strength and durability of adhesively bonded joints

In this in vitro study, the effect of substrate surface area and substrate thickness on the strength and durability of an adhesively bonded joint was evaluated. Sixty metal substrate samples were cast out of a cobalt-chromium alloy. Samples of the first group were in a disk shape of 2 mm thickness and 35 mm2, 65 mm2, and 95 mm2 surface area with a U-shaped loop on the non-testing side. Samples of the second group were in the shape of disks of surface area 65 mm2 with a U-shaped loop and thicknesses of 0.5 mm, 1 mm, or 2 mm. All samples were treated by the Silicoater MD® method and bonded with bisphenol-A glycidyl methacrylate (Bis-GMA) adhesive. Samples were either stored in distilled water for 3 days or thermocycled for 5000 cycles followed by storage for 180 days in water at 37 °C. After storage, the tensile bond strength was determined. Increasing the bonded surface area resulted in a significant drop in the initial bond strength values. However, after thermocycling and water storage, the bond strength increased with increasing bonded surface area. Increasing the substrate thickness resulted in a significant increase of the initial bond strength values. After thermocycling and water storage, there were no significant differences in the bond strength values for samples with different thicknesses.

Bond strengths of resin-to-metal bonding systems

Statement of problem. Resinous materials for the veneers of fixed prostheses commonly require mechanical retention on metal substructures because there is no chemical adhesion. However, mechanical retention does not restrict creation of a marginal gap at the resin-metal interface, which can cause discoloration or detachment of resinous material. The development of a chemical resin-to-metal bonding could resolve this problem and also reduce the need for mechanical retention (pearls, wires) on metal frameworks. Purpose. This study evaluated six current methods with the use of various storage conditions to predict clinical efficacy. Material and methods. Six resin-to-metal bonding systems were tested: Silicoater, Silicoater MD, Rocatec, OVS, Sebond, and Spectra-Link. All specimens were examined in bending tests after 24 hours of dry storage (category A), after 24 hours of water storage and thermocycling (category B), and after 2 months of water storage and thermocycling (category C). Tensional tests were completed for all bonding systems after dry storage, and microscopic examination (optical and SEM) was performed for all specimens. Results and Conclusions. This study indicated that certain systems can provide stable bonding of resin to metal substructures despite prolonged wet storage and intensive thermocycling. These systems can also be used clinically without retentive configurations on metal frameworks, resulting in better esthetics. Some bonding systems revealed progressive weakening of bond strengths, so research is needed to verify their clinical efficacy. (J Prosthet Dent 1997;78:136-145.)

Shear bond strength of four commercial bonding systems to cpTi

Objectives. The purpose of this study was to evaluate the bond strength of veneering composite to commercially pure titanium (cpTi) using several different bonding systems and a post-cure heat treatment. Methods. Four commercial bonding systems (Cesead, Kuraray; New Metacolor, Sun Medical; Silicoater MD, Kulzer; Thermoresin LC II, GC) were evaluated. Bonding was attempted with the opaque resin provided by each bonding system as well as with the New Metacolor opaque resin. New Metacolor resin composite was used for the veneering composite. Half of the specimens were subjected to a post-cure heat treatment at 100°C for 30 min. The shear bond strengths were tested after aging the specimens in water at 37°C for 1 d and also after thermocycling for 16.5 d (20,000 cycles). Results. Strong bonds, exceeding 20 MPa, were achieved with all of the bonding systems with the exception of Thermoresin LC II, which is designed for noble metals. Bond strengths were only increased by the post-cure heat treatment for the New Metacolor system. Thermocycling caused a significant reduction in bond strength for the New Metacolor and the Thermoresin LC II systems. The use of the New Metacolor opaque resin produced increased bonding for the Silicoater MD and the Cesead systems, but the effect was eliminated after thermocycling. Significance. Strong, durable bonds can be achieved between composite and sandblasted cpTi, thus enhancing the usefulness of this metal for esthetic resin-veneered crowns and other fixed prosthetics.

Effects of sandblasting and silica-coating procedures on pure titanium

Silica coating titanium improves chemomechanical bonding. Sandblasting is recommended as a pretreatment to thermal silica coating (Silicoater MD) or as part of a tribochemical silica coating process (Rocatec). This study evaluated the effects of sandblasting and coating techniques on volume loss, surface morphology and composition changes in pure titanium. Volume loss of titanium was similar to values reported for base alloys and does not seem to be critical for the clinical fit of restorations. Embedded alumina particles were found in the titanium after sandblasting and the alumina content increased to a range of 27.5–39.3 wt% as measured by EDS. Following tribochemical silica coating, a layer of small silica particles remained on the surface, increasing the silica content to a range of 17.9–19.5 wt%. Ultrasonic cleaning removed loose alumina or silica particles from the surface, resulting in only slight decreases in alumina or silica contents, suggesting firm attachment of most of the alumina and silica to the titanium surface. Silica content following thermal silica coating treatment increased only slightly from the sandblasted specimen to 1.4 wt%. The silica layer employed by these silica coating methods differs widely in both morphology and thickness. These results provide a basis for explanation of adhesive failure modes in bond strength tests and for developing methods to optimize resin bonding. Clinically, ultrasonic cleaning of sandblasted and tribochemically silica coated titanium should improve resin bonding as loose surface particles are removed without relevant changes in composition.

Sandblasting and silica coating of a glass-infiltrated alumina ceramic: Volume loss, morphology, and changes in the surface composition

Silica coating can improve bonding of resin to glass-infiltrated aluminum oxide ceramic (In-Ceram), and sandblasting is a pretreatment to thermal silica coating (Silicoater MD system) or a tribochemical coating process (Rocatec system). This study evaluated the effects of sandblasting and coating techniques on volume loss, surface morphology, and surface composition of In-Ceram ceramic. Volume loss through sandblasting was 36 times less for In-Ceram ceramic compared with a feldspathic glass ceramic (IPS-Empress), and sandblasting of In-Ceram ceramic did not change its surface composition. After tribochemical coating with the Rocatec system, a layer of small silica particles remained that elevated the silica content to 19.7 weight percentage (energy-dispersive spectroscopy). Ultrasonic cleaning removed loose silica particles from the surface and decreased the silica content to 15.8 weight percentage, which suggested firm attachment of most of the silica layer to the surface. After treatment with the Silicoater MD system, the silica content increased only slightly from that of the sandblasted specimen. The silica layer created by these systems differs greatly in both morphology and thickness, which could result in different bond strengths. Sandblasting of all ceramic clinical restorations with feldspathic glass materials should be avoided, but for In-Ceram ceramic the volume loss was within an acceptable range and similar to that of noble metals.

キャストクラスプに対する硬質レジンコーティング法の応用 第１報 こう腕の曲げ剛性への影響

The purpose of this study was to examine the bending profiles of composite resin coating cast clasps. The I-bar and Akers clasps made of cobalt-chromium alloy were cast using a tapered wax pattern. One of the chemical bonding methods (Silicoater MD, Kulzer Co.) wasapplied to adhere composite resin to a metal surface. The breakage and the bending rigidity ofcomposite resin coating clasps were evaluated.The results were as follows:1. There was no significant difference in the bending rigidities of clasp arms between beforeand after composite resin coating.2. After repeated bending tests to the tips of the clasp arm at 10, 000 times in 0.25mmdeflection, neither crack in composite resin surfaces nor separation in resin/metal interfaces wasoccurred in any specimen.From these results, it was indicated that the composite resin coating cast clasps could be appliedto clinical cases and the bending rigidities were controllable in the same way as conventional castclasps.