Effects of sandblasting and silica-coating procedures on pure titanium

Effect of various surface treatment methods on shear bond strength between acrylic denture teeth and thermoplastic nylon denture base

PURPOSE

To evaluate the effect of mechanical, chemical, and mechanical-chemical surface treatment methods on shear bond strength between acrylic denture teeth and thermoplastic nylon denture base.

MATERIALS AND METHODS

Maxillary central incisor teeth were treated with five different surface treatment methods: mechanical (sandblasting, T-shape diatoric holes), chemical (5% acetic acid solution, bonding agent), and mechanical-chemical (sandblasting + bonding agent) were embedded in thermoplastic nylon denture base (n = 10). A universal testing machine with a crosshead speed of 0.5 mm per minute was used to test the shear bond strength. Data obtained were statistically evaluated using one-way ANOVA and followed with Tukey post hoc test (α = 0.05) RESULTS: T-shaped diatoric holes exhibited significantly higher shear bond strength among the surface treatment groups, followed by sandblasting + bonding agent, sandblasting, bonding agent, and the acetic acid group (p < 0.001) CONCLUSION: T-shaped diatoric holes as a mechanical surface treatment showed higher shear bond strength than other methods.

Effect of Er:YAG Pulsed Laser-Deposited Hydroxyapatite Film on Titanium Implants on M2 Macrophage Polarization In Vitro and Osteogenesis In Vivo

In a previous study, we successfully coated hydroxyapatite (HAp) onto titanium (Ti) plates using the erbium-doped yttrium aluminum garnet pulsed-laser deposition (Er:YAG-PLD) method. In this study, we performed further experiments to validate the in vitro osteogenic properties, macrophage polarization, and in vivo osseointegration activity of HAp-coated Ti (HAp-Ti) plates and screws. Briefly, we coated a HAp film onto the surfaces of Ti plates and screws via Er:YAG-PLD. The surface morphological, elemental, and crystallographic analyses confirmed the successful surface coating. The macrophage polarization and osteogenic induction were evaluated in macrophages and rat bone marrow mesenchymal stem cells, and the in vivo osteogenic properties were studied. The results showed that needle-shaped nano-HAp promoted the early expression of osteogenic and immunogenic genes in the macrophages and induced excellent M2 polarization properties. The calcium deposition and osteocalcin production were significantly higher in the HAp-Ti than in the uncoated Ti. The implantation into rat femurs revealed that the HAp-coated materials had superior osteoinductive and osseointegration activities compared with the Ti, as assessed by microcomputed tomography and histology. Thus, HAp film on sandblasted Ti plates and screws via Er:YAG-PLD enhances hard-tissue differentiation, macrophage polarization, and new bone formation in tissues surrounding implants both in vitro and in vivo.

There Are over 60 Ways to Produce Biocompatible Calcium Orthophosphate (CaPO4) Deposits on Various Substrates

A The present overview describes various production techniques for biocompatible calcium orthophosphate (abbreviated as CaPO4) deposits (coatings, films and layers) on the surfaces of various types of substrates to impart the biocompatible properties for artificial bone grafts. Since, after being implanted, the grafts always interact with the surrounding biological tissues at the interfaces, their surface properties are considered critical to clinical success. Due to the limited number of materials that can be tolerated in vivo, a new specialty of surface engineering has been developed to desirably modify any unacceptable material surface characteristics while maintaining the useful bulk performance. In 1975, the development of this approach led to the emergence of a special class of artificial bone grafts, in which various mechanically stable (and thus suitable for load-bearing applications) implantable biomaterials and artificial devices were coated with CaPO4. Since then, more than 7500 papers have been published on this subject and more than 500 new publications are added annually. In this review, a comprehensive analysis of the available literature has been performed with the main goal of finding as many deposition techniques as possible and more than 60 methods (double that if all known modifications are counted) for producing CaPO4 deposits on various substrates have been systematically described. Thus, besides the introduction, general knowledge and terminology, this review consists of two unequal parts. The first (bigger) part is a comprehensive summary of the known CaPO4 deposition techniques both currently used and discontinued/underdeveloped ones with brief descriptions of their major physical and chemical principles coupled with the key process parameters (when possible) to inform readers of their existence and remind them of the unused ones. The second (smaller) part includes fleeting essays on the most important properties and current biomedical applications of the CaPO4 deposits with an indication of possible future developments.

Characterization of Hydroxyapatite Film Obtained by Er:YAG Pulsed Laser Deposition on Sandblasted Titanium: An In Vitro Study

The surface of titanium (Ti) dental implants must be modified to improve their applicability, owing to the biological inertness of Ti. This study aims to use sandblasting as a pretreatment method and prepare a hydroxyapatite (HA) coating on Ti to improve its biocompatibility and induce bone bonding and osteogenesis. In this paper, sandblasted Ti discs were coated with α-tricalcium phosphate (α-TCP) via Er:YAG pulsed laser deposition (Er:YAG-PLD). An HA coating was then obtained via the hydrothermal treatment of the discs at 90 °C for 10 h. The surface characteristics of the samples were evaluated by SEM, SPM, XPS, XRD, FTIR, and tensile tests. Rat bone marrow mesenchymal stem cells were seeded on the HA-coated discs to determine cellular responses in vitro. The surface characterization results indicated the successful transformation of the HA coating with a nanorod-like morphology, and its surface roughness increased. In vitro experiments revealed increased cell attachment on the HA-coated discs, as did the cell morphology of fluorescence staining and SEM analysis; in contrast, there was no increase in cell proliferation. This study confirms that Er:YAG-PLD could be used as an implant surface-modification technique to prepare HA coatings with a nanorod-like morphology on Ti discs.

The Evaluation of Microshear Bond Strength of Resin Cements to Titanium Using Different Surface Treatment Methods: An In Vitro Study

This study attempted to investigate the effect of sandblasting and H2O2 treatments on the microshear bond strength of two commercially available resin cements. A total of 90 cube-shaped specimens of commercially pure titanium (cp-Ti) were divided into two groups of Panavia and MHA cements (n = 45). Samples of the Panavia group were randomly divided into three subgroups of 15 samples, including subgroups (no treatment, aluminum oxide sandblasting, and immersion in 35% hydrogen peroxide solution with halogen light). Once the treatment was completed, Panavia V5 was applied on the cp-Ti surface by a Tygon tube. The 45 specimens of the MHA cement group were randomly divided into three subgroups (n = 15) similarly to the Panavia group. Then, the MHA was applied on the surface of cp-Ti. A universal testing machine was used to measure and examine the microshear bond strength of cement to cp-Ti subsequent to the step of thermocycling. According to results, in the Panavia cement group, the SBS of sandblasting treatment was significantly higher than that of the H2O2 treatment subgroup (p < 0.05), which displayed a significantly higher SBS than that of the no-treatment subgroup (p < 0.001). In regard to the MHA group, the SBS of the H2O2 treatment subgroup was significantly lower than that of the sandblasting treatment subgroup (p < 0.001), whereas there were no significant differences between the SBS of the no treatment and H2O2 treatment subgroups (p = 0.35). Considering the comparison between Panavia and MHA cases, there were no significant differences observed among the no-treatment subgroups (p = 0.34), as well as the sandblasting treatment subgroups (p = 0.67), while the SBS of the H2O2 treatment subgroup in Panavia cement was higher than that of the H2O2 subgroup in MHA cement (p < 0.001). In conclusion, in both Panavia V5 and MHA cements, sandblasting treatment could improve the bond strength between the titanium surface. However, H2O2 treatment proved to be capable of enhancing the bond strength of Panavia V5 cement without causing any positive effects on the bond strength of MHA cement.

Surface engineering and the application of laser-based processes to stents - A review of the latest development

Late in-stent thrombus and restenosis still represent two major challenges in stents’ design. Surface treatment of stent is attracting attention due to the increasing importance of stenting intervention for coronary artery diseases. Several surface engineering techniques have been utilised to improve the biological response in vivo on a wide range of biomedical devices. As a tailorable, precise, and ultra-fast process, laser surface engineering offers the potential to treat stent materials and fabricate various 3D textures, including grooves, pillars, nanowires, porous and freeform structures, while also modifying surface chemistry through nitridation, oxidation and coatings. Laser-based processes can reduce the biodegradable materials' degradation rate, offering many advantages to improve stents’ performance, such as increased endothelialisation rate, prohibition of SMC proliferation, reduced platelet adhesion and controlled corrosion and degradation. Nowadays, adequate research has been conducted on laser surface texturing and surface chemistry modification. Laser texturing on commercial stents has been also investigated and a promotion of performance of laser-textured stents has been proved.

In this critical review, the influence of surface texture and surface chemistry on stents performance is firstly reviewed to understand the surface characteristics of stents required to facilitate cellular response. This is followed by the explicit illustration of laser surface engineering of stents and/or related materials. Laser induced periodic surface structure (LIPSS) on stent materials is then explored, and finally the application of laser surface modification techniques on latest generation of stent devices is highlighted to provide future trends and research direction on laser surface engineering of stents.

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Compared conventional surface engineering with laser-based methods for biomedical devices.

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Explained the influence of texture geometry and surface chemistry on stents biological response.

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Reviewed state of the art in laser surface engineering of stents for improved biological response.

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Reviewed state of the art in laser surface engineering to control degradation of bioresorbable stents.

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Highlighted novel laser surface engineering designs for improved stents'performance.

Review on Adhesives and Surface Treatments for Structural Applications: Recent Developments on Sustainability and Implementation for Metal and Composite Substrates

Using adhesives for connection technology has many benefits. It is cost-efficient, fast, and allows homogeneous stress distribution between the bonded surfaces. This paper gives an overview on the current state of knowledge regarding the technologically important area of adhesive materials, as well as on emergent related technologies. It is expected to fill some of the technological gaps between the existing literature and industrial reality, by focusing at opportunities and challenges in the adhesives sector, on sustainable and eco-friendly chemistries that enable bio-derived adhesives, recycling and debonding, as well as giving a brief overview on the surface treatment approaches involved in the adhesive application process, with major focus on metal and polymer matrix composites. Finally, some thoughts on the connection between research and development (R&D) efforts, industry standards and regulatory aspects are given. It contributes to bridge the gap between industry and research institutes/academy. Examples from the aeronautics industry are often used since many technological advances in this industry are innovation precursors for other industries. This paper is mainly addressed to chemists, materials scientists, materials engineers, and decision-makers.

Effect of reduced airborne-particle abrasion pressure on the retention of zirconia copings resin bonded to titanium abutments

STATEMENT OF PROBLEM

The optimal conditioning of zirconia is essential for a durable bond between zirconia copings and titanium inserts in 2-piece dental implant abutments. Low-pressure activation of the zirconia surface may be adequate for retention.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of airborne-particle abrasion (APA) of the zirconia surface with different pressures on the retention of zirconia copings bonded to titanium abutments. In addition, 2 luting systems were compared.

MATERIAL AND METHODS

Computer-aided design and computer-aided manufacturing (CAD-CAM) zirconia copings were divided into 3 groups (n=32): 0.1 MPa, 0.25 MPa, and not airborne-particle abraded surfaces with 50-μm alumina (Al₂O₃) particles. Compatible titanium abutments were airborne-particle abraded at a pressure of 0.25 MPa. All specimens were ultrasonically cleaned before bonding. Each group was divided into 2 subgroups (n=16) with different luting composite resins. A 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) containing self-adhesive luting composite resin (Panavia SA Cement Plus) and a conventional luting composite resin (Multilink Hybrid Abutment) in combination with a 10-MDP-containing universal primer (Monobond Plus) was compared. Two storage conditions were tested: in water (37 °C) for 3 days or 150 days with 37 500 thermocycles between 5 °C and 55 °C. After artificial aging, retention was measured in tension, and the failure modes were analyzed by using a light microscope and a scanning electron microscope. Statistical analysis was performed with 1-way ANOVA and the Games-Howell test for post hoc analysis (α=.05).

RESULTS

The mean retention of the airborne-particle abraded groups ranged from 576.0 N to 1049.3 N after 150 days of water storage and 37 500 thermocycles. No significant difference in bond strength was found between the 2 luting composite resin groups with airborne-particle abraded zirconia surfaces after 150 days (P<.05). Both bonding systems provided durable bond strength after 3 and 150 days. Failure mode was mainly cohesive at the titanium surfaces and predominantly adhesive at the zirconia surfaces. The retention was significantly higher if APA was used versus no APA (P<.05), while the APA pressure used made no significant difference.

CONCLUSIONS

The APA of zirconia copings at a pressure of 0.1 MPa in combination with 10-MDP-containing luting composite resins and primers is adequate for the durable bonding of zirconia copings to titanium inserts.

Influence of ultraviolet irradiation treatment on porcelain bond strength of titanium surfaces

To determine the effect of titanium (Ti) surface modification by ultraviolet irradiation (UVI) on the bond strength between Ti and porcelain. Grade 2 Ti plates were allotted to five groups: sandblasted (SA), 15 min UVI (UV), SA+5 min UVI (SA+UV5), SA+10 min UVI (SA+UV10), and SA+15 min UVI (SA+UV15). After surface treatment, porcelain was added. A precious metal (MC) was used for comparison with Ti. The effects of 24-h storage at room temperature versus thermal cycling only at 5 and 55°C in water were evaluated. Subsequently, the tensile strength of each sample was tested. Data were analyzed using one-way analysis of variance and the Tukey test. In both the room temperature and thermal cycling groups, the MC and SA+15 min UVI samples showed significantly greater bond strengths than the other samples (p<0.05). UVI processing efficiently increases the bond strength between porcelain and the Ti surface.

Effect of Alumina Particle Size on the Bond Strength between Autopolymerized Acrylic Resin and Commercially Pure Titanium

PURPOSE

To address the following null hypothesis: when the Rocatec bonding system is used, the various sizes of aluminum oxide particles used to roughen the surface area of the commercially pure (CP) titanium prior to bonding to autopolymerized resin have no effect on the average shear bond strength.

MATERIALS AND METHODS

One hundred specimens were randomly allocated to five equally sized groups: Ti-no air abrasion (group A), Ti-air-abraded with 50 μm (group B), Ti-110 μm (group C), Ti-250 μm (group D), and Co-Cr-50 μm (group E) grain-size aluminum oxide. Rocatec Plus tribochemical coating was applied to all of the specimens, followed by a RelyX primer and Sinfonyopaquer. Autopolymerized denture base resin was then bonded to the treated titanium surfaces. All specimens underwent thermocycling (10,000 cycles), shear bond testing, and mode of failure examination under stereoscopic microscopy.

RESULTS

The average bond strength of group D (250 μm) was significantly different compared to all other groups, except group C (p = 0.057, trending significance). The average bond strength of group D was substantially higher than that in the other groups (p < 0.01). The weakest bond was observed when the specimens did not receive any air abrasion (group A). Maximum load (N) showed the same significant results as the shear bond strength at maximum load (MPa). The average extension at maximum load (mm) and the time at maximum load(s) for group A were significantly different than that of all other groups. Group A had lower average values than any other group (p = 0.003). More cohesive and mixed, rather than adhesive, modes of failure were observed as the size of the aluminum oxide particles increased.

CONCLUSION

When the Rocatec system is used, using a combination of chemical and micromechanical adhesion is essential for the success of the bond between the autopolymerized acrylic resin and CP Ti. The micromechanical interlock can be improved significantly when the Ti surface is air abraded with larger particles (250 μm) than the currently used alumina particle size.

Bonding durability between acrylic resin adhesives and titanium with surface preparations

The purpose of the present study was to evaluate the efficacy of pretreatment on the bonding durability between titanium casting and two acrylic adhesives. Cast titanium disk specimens treated with four polymer-metal bonding systems as follow: 1) air-abraded with 50-70 μm alumina, 2) 1)+Alloy Primer, 3) 1)+M.L. Primer and 4) tribochemical silica/silane coating system (Rocatec System). The specimens were bonded with M bond or Super-bond C&B adhesive. The shear bond strengths were determined before and after thermocycling (20,000 cycles). The surface characteristics after polishing, and for the 1) and 4) preparations were determined. The bond strengths for all combinations significantly decreased after thermocycling. The combination of Super-bond C&B adhesive and 2) led to significantly higher bond strength than the other preparations after thermocycling. The maximum height of the profile parameters for the polishing group was lower than other preparations.

The Effect of Hydrofluoric Acid Etching Duration on the Surface Micromorphology, Roughness, and Wettability of Dental Ceramics

The current laboratory study is evaluating the effect of hydrofluoric acid etching duration on the surface characteristics of five silica-based glass ceramics. Changes in the pore pattern, crystal structure, roughness, and wettability were compared and evaluated. Seventy-five rectangularly shaped specimens were cut from each material (IPS e-max™, Dentsply Celtra™, Vita Suprinity™, Vita mark II™, and Vita Suprinity FC™); the sectioned samples were finished, polished, and ultrasonically cleaned. Specimens were randomly assigned into study groups: control (no etching) and four experimental groups (20, 40, 80 and 160 s of etching). The etched surfaces’ microstructure including crystal structure, pore pattern, pore depth, and pore width was studied under a scanning electron microscope, and the surface roughness and wettability were analyzed using a non-contact surface profilometer and a contact angle measuring device, respectively. The results were statistically analyzed using one-way analysis of variance (ANOVA) and the post hoc Tukey’s test. The results showed a significant change in the pore number, pore pattern, crystal structure, surface roughness, and wettability with increased etching duration. Etching for a short time resulted in small pores, and etching for longer times resulted in wider, irregular grooves. A significant increase in the surface roughness and wettability was observed with an increase in the etching duration. The findings also suggested a strong association between the surface roughness and wettability.

Effects of silica-coating on surface topography and bond strength of porcelain fused to CAD/CAM pure titanium

The aim of this study was to evaluate the shear bond strength of porcelain fusing to titanium and the effects of surface treatment on surface structure of titanium. In the shear bond strength test, titanium surface treatments were: conventional, silica-coating without bonding agent, and silica-coating with bonding agent. Titanium surface treatments for analysis by the atomic force microscope (AFM) were: polishing, alumina sandblasting and silica-coating. The shear bond strength value of silica-coating with bonding agent group showed significantly higher than that of other groups. In AFM observation results, regular foamy structure which is effective for wetting was only observed in silica-coating. Therefore, this structure might indicate silicon. Silica-coating renders forms a nanoscopic regular foamy structure, involved in superhydrophilicity, to titanium surface, which is markedly different from the irregular surface generated by alumina sandblasting.

Calcium orthophosphate deposits: Preparation, properties and biomedical applications

Since various interactions among cells, surrounding tissues and implanted biomaterials always occur at their interfaces, the surface properties of potential implants appear to be of paramount importance for the clinical success. In view of the fact that a limited amount of materials appear to be tolerated by living organisms, a special discipline called surface engineering was developed to initiate the desirable changes to the exterior properties of various materials but still maintaining their useful bulk performances. In 1975, this approach resulted in the introduction of a special class of artificial bone grafts, composed of various mechanically stable (consequently, suitable for load bearing applications) implantable biomaterials and/or bio-devices covered by calcium orthophosphates (CaPO4) to both improve biocompatibility and provide an adequate bonding to the adjacent bones. Over 5000 publications on this topic were published since then. Therefore, a thorough analysis of the available literature has been performed and about 50 (this number is doubled, if all possible modifications are counted) deposition techniques of CaPO4 have been revealed, systematized and described. These CaPO4 deposits (coatings, films and layers) used to improve the surface properties of various types of artificial implants are the topic of this review.

Effect of engraving speeds of CO₂ laser irradiation on In-Ceram Alumina roughness: a pilot study

OBJECTIVES

The aim of the study was to determine the effect of CO₂ laser on surface roughness of In-Ceram-Alumina-ceramic.

MATERIALS AND METHODS

Four aluminum-oxide ceramic disc specimens were prepared of In-Ceram Alumina. Discs received CO₂ laser irradiation with different engraving speeds (100, 400, 600 and 800 mm/min) as a surface treatment. The roughness of the surfaces was measured on digital elevation models reconstructed from stereoscopic images acquired by scanning-electron-microscope. Surface roughness data were analyzed with One-Way-Analysis-of-Variance at a significance level of p<0.05.

RESULTS

There was no significant difference between the roughness values (p=0.82). Due to higher laser durations, partial melting signs were observed on the surfaces. Tearing, smearing and swelling occurred on melted surfaces. Swelling accompanying melting increased the surface roughness, while laser power was fixed and different laser engraving speeds were applied.

CONCLUSION

Although different laser irradiation speeds did not affect the roughness of ceramic surfaces, swelling was observed which led to changes on surfaces.

The effect of thermal cycling on the shear bond strength of porcelain/Ti-6Al-4V interfaces

The aim of the study was to evaluate the effect of thermal cycling on the shear bond strength of the porcelain/Ti-6Al-4V interfaces prepared by two different processing routes and metallic surface conditions. Polished and SiO2 particle abraded Ti-6Al-4V alloy and Triceram bonder porcelain were used to produce the interfaces. Porcelain-to-metal specimens were processed by conventional furnace firing and hot pressing. Thermal cycling was performed in Fusayama's artificial saliva for 5000 cycles between 5 ± 1 and 60 ± 2°C. After thermal cycling, shear bond tests were carried out by using a custom-made stainless steel apparatus. The results were analyzed using t-Student test and non-parametric Kruskal-Wallis test (p<0.01). Most of the polished-fired specimens were fractured during thermal cycling; thus, it was not possible to obtain the shear bond strength results for this group. Sandblasted-fired, polished-hot pressed, and sandblasted-hot pressed specimens presented the shear bond strength values of 76.2 ± 15.9, 52.2 ± 23.6, and 59.9 ± 22.0 MPa, respectively. Statistical analysis indicated that thermal cycling affected the polished specimens processed by firing, whereas a significant difference was not observed on the other groups.

Effect of recycling protocol on mechanical strength of used mini-implants

Purpose. This study evaluated the influence of recycling process on the torsional strength of mini-implants. Materials and Methods. Two hundred mini-implants were divided into 4 groups with 50 screws equally distributed in five diameters (1.3 to 1.7 mm): control group (CG): unused mini-implants, G1: mini-implants inserted in pig iliac bone and removed, G2: same protocol of group 1 followed by sonication for cleaning and autoclave sterilization, and G3: same insertion protocol of group 1 followed by sonication for cleaning before and after sandblasting (Al₂O₃-90 µ) and autoclave sterilization. G2 and G3 mini-implants were weighed after recycling process to evaluate weight loss (W). All the screws were broken to determine the fracture torque (FT). The influence of recycling process on FT and W was evaluated by ANOVA, Mann-Whitney, and multiple linear regression analysis. Results. FT was not influenced by recycling protocols even when sandblasting was added. Sandblasting caused weight loss due to abrasive mechanical stripping of screw surface. Screw diameter was the only variable that affected FT. Conclusions. Torsional strengths of screws that underwent the recycling protocols were not changed. Thus, screw diameter choice can be a more critical step to avoid screw fracture than recycling decision.

Adhesive bonding of resin composite to various titanium surfaces using different metal conditioners and a surface modification system

Objective

This study evaluated the effect of three metal conditioners on the shear bond strength (SBS) of a prosthetic composite material to cpTi grade I having three surface treatments.

Material and Methods

One hundred sixty eight rivet-shaped specimens (8.0x2.0 mm) were cast and subjected to polishing (P) or sandblasting with either 50 mm (50SB) or 250 mm (250SB) Al₂O₃. The metal conditioners Metal Photo Primer (MPP), Cesead II Opaque Primer (OP), Targis Link (TL), and one surface modification system Siloc (S), were applied to the specimen surfaces, which were covered with four 1-mm thick layers of resin composite. The resin layers were exposed to curing light for 90 s separately. Seven specimens from each experimental group were stored in water at 37ºC for 24 h while the other 7 specimens were subjected to 5,000 thermal cycles consisting of water baths at 4ºC and 60ºC (n=7). All specimens were subjected to SBS test (0.5 mm/min) until failure occurred, and further 28 specimens were analyzed using scanning electron microscope (SEM) and X-ray energy-dispersive spectroscopy (EDS). Data were analyzed by 3-way ANOVA followed by post-hoc Tukey's test (α=0.05).

Results

On 50SB surfaces, OP groups showed higher SBS means than MPP (P<0.05), while no significant difference was found among OP, S, and TL groups. On 250SB surfaces, OP and TL groups exhibited higher SBS than MPP and S (P<0.05). No significant difference in SBS was found between OP and TL groups nor between MPP and S groups. The use of conditioners on 250SB surfaces resulted in higher SBS means than the use of the same products on 50SB surfaces (P<0.05).

Conclusion

Sandblasting associated with the use of metal conditioners improves SBS of resin composites to cpTi.

Investigation into the effect of use of metal primer on adhesion of heat cure acrylic resin to cast titanium: an in vitro study

The availability of adhesive primers capable of bonding chemically to base metal alloys without well defined passive oxide surface film has been improved significantly over the last decade. Therefore, the purpose of the study was to compare and evaluate the effect of metal primer on adhesion of heat cure acrylic resin to cast titanium. Shear bond strength test was conducted on 80 commercially pure titanium cast metal heat-cure acrylic resin discs treated with different surface treatments. The first group received no surface treatment (group I); the second group was subjected to sandblasting (group II); the third group was treated with bonding agent (alloy primer) (group III) and the fourth was treated with sandblasting and alloy primer (group IV). After the samples were surface treated, acrylic resin was mixed, packed and processed over the test area of cast titanium. Ten specimens of each group were immersed in distilled water for 24 h followed by thermocycling for 20,000 cycles. Shear bond-strength between the heat cure acrylic resin and titanium was evaluated using Instron universal testing machine. Debonded specimens of all the groups were subjected to SEM analysis. The bond failure (MPa) was analyzed by ANOVA and Duncan's multiple comparison tests. Surface treatment with sandblasting, followed by the application of alloy primer showed maximum shear bond strength before and after thermocycling (24.50 ± 0.59 and 17.39 ± 1.56 MPa respectively).The bond strength values are found to be in decreasing magnitudes as group IV > group III > group II > group I. The following pretreatment to improve the shear bond strength of heat cure acrylic resin to titanium is recommended in order to attain the maximum bond strength in cast titanium frameworks for various prostheses: sandblasting, cleaning in an ultrasonic bath for 10 min and air drying followed by application of a bonding agent uniformly on the sandblasted cast titanium surface before packing with heat cure acrylic resin.

Effect of different airborne-particle abrasion/bonding agent combinations on the bond strength of a resin cement to a base metal alloy

STATEMENT OF PROBLEM

Investigation of surface treatments to improve the bond of resin cements to metals may contribute to the longevity of metal ceramic restorations.

PURPOSE

The purpose of this study was to evaluate the efficacy of surface treatments on the shear bond strength (SBS) of a resin cement to nickel-chromium (NiCr) alloy.

MATERIAL AND METHODS

Eighty cast NiCr alloy disks (9 × 3 mm) were divided into 8 groups (n=10), which received 1 of the following surface treatments: 1) 50 µm Al(2)O(3) particles + silane; 2) 120 µm Al(2)O(3) + silane; 3) 30 µm silica-modified Al(2)O(3) (Cojet Sand) + silane; 4) 120 µm Al(2)O(3) followed by 110 µm silica-modified Al(2)O(3) (Rocatec) + silane; 5) 50 µm Al(2)O(3) + metal primer; 6) 120 µm Al(2)O(3) + metal primer; 7) 30 µm silica-modified Al(2)O(3) (Cojet Sand) + metal primer; and 8) 120 µm Al(2)O(3) followed by 110 µm silica-modified Al(2)O(3) (Rocatec) + metal primer. The silane was RelyX Ceramic Primer and the metal primer Alloy Primer. RelyX ARC resin cement was bonded to NiCr alloy surfaces. Specimens were thermally cycled before shear mode testing. Data (MPa) were analyzed by 1-way ANOVA and the Tukey test (α=.05). Failure mode was determined with a stereomicroscope (×20).

RESULTS

The results revealed that surface treatment was significant (P<.001). There was no significant difference between 50 µm and 120 µm Al(2)O(3) particles, regardless of the bonding agent used (silane or metal primer). Cojet Sand provided lower SBS than Rocatec, both in the groups treated with silane (P<.001) and metal primer (P<.01). No significant difference was observed between silane and metal primer in the groups abraded with 50 µm and 120 µm Al(2)O(3) particles. Metal primer decreased the SBS of both Cojet Sand and Rocatec groups (P<.001). Rocatec + silane had the highest SBS and Cojet Sand + metal primer the lowest. All groups presented 100% adhesive failure.

CONCLUSIONS

Particle size influenced SBS only in the groups abraded with silica-modified Al(2)O(3). The bonding agent did not affect SBS in the groups abraded with Al(2)O(3). Alloy Primer was not chemically compatible with silica-modified Al(2)O(3). Both mechanical (particle size) and chemical (silica/silane interaction) factors contributed to the high SBS of Rocatec + silane.

Influence of the processing route of porcelain/Ti-6Al-4V interfaces on shear bond strength

This study aims at evaluating the two-fold effect of initial surface conditions and dental porcelain-to-Ti-6Al-4V alloy joining processing route on the shear bond strength. Porcelain-to-Ti-6Al-4V samples were processed by conventional furnace firing (porcelain-fused-to-metal) and hot pressing. Prior to the processing, Ti-6Al-4V cylinders were prepared by three different surface treatments: polishing, alumina or silica blasting. Within the firing process, polished and alumina blasted samples were subjected to two different cooling rates: air cooling and a slower cooling rate (65°C/min). Metal/porcelain bond strength was evaluated by shear bond test. The data were analyzed using one-way ANOVA followed by Tuckey's test (p<0.05). Before and after shear bond tests, metallic surfaces and metal/ceramic interfaces were examined by Field Emission Gun Scanning Electron Microscope (FEG-SEM) equipped with Energy Dispersive X-Ray Spectroscopy (EDS). Shear bond strength values of the porcelain-to-Ti-6Al-4V alloy interfaces ranged from 27.1±8.9MPa for porcelain fused to polished samples up to 134.0±43.4MPa for porcelain fused to alumina blasted samples. According to the statistical analysis, no significant difference were found on the shear bond strength values for different cooling rates. Processing method was statistically significant only for the polished samples, and airborne particle abrasion was statistically significant only for the fired samples. The type of the blasting material did not cause a statistically significant difference on the shear bond strength values. Shear bond strength of dental porcelain to Ti-6Al-4V alloys can be significantly improved from controlled conditions of surface treatments and processing methods.

Effect of thermocycling on the bond strength of a glass-infiltrated ceramic and a resin luting cement

The aim of the present study was to evaluate the effect of thermocycling on the bond strength between the surface of the glass-infiltrated alumina ceramic In-Ceram (VITA) and the Panavia F resin cement (Kuraray CO.). Four 5x6x6mm In-Ceram blocks were obtained. One of the 6x6mm faces of each block was conditioned with Cojet - System (tribochemical silica coating, ESPE-3M) and then luted under a constant 750g pressure with Panavia F cement to another identical face of a resin composit block (Clearfil AP-X, Kuraray) obtained by reproduction of the ceramic one from Express (3M) addition curing silicone impressions. The four sets so formed by ceramic, luting cement and resin have been each one serially sectioned in 20 sticks so that the adhesive surface in each presented 1mm² of area. The samples were divided in 2 groups (n=10): G1- stored for 7 days in deionized water at 36 ± 2ºC; G2 - thermocycled 1500 times between 5 and 55ºC dwell times. The microtensile tests were accomplished in an universal testing machine (EMIC) at a crosshead speed of 0,5 mm/min. The results showed that the mean tensile bond strength values (MPa) for the group G2: (22,815 ± 5,254) had not statistically differ of the values of group G1: (25,628 ± 3,353) (t = 1,427; gl = 18; p-value = 0,171), at the level of a= 5%. It can be concluded that the thermocycling technique used in the present experiment had not produced statistically significant differences between the bond strength results of the specimens obtained by the two used techniques.

Characterization of novel silane coatings on titanium implant surfaces

OBJECTIVES

This in vitro study describes and characterizes a developed novel method to produce coatings on Ti. Hydrophobic coatings on substrates are needed in prosthetic dentistry to promote durable adhesion between luting resin cements and coated Ti surfaces. In implant dentistry the hydrophobic coatings on a Ti implant might be beneficial for osseointegration, preventing bacteria adhesion and for enhancement of resin composite adhesion as well.

MATERIALS AND METHODS

A silica-coating system, Rocatec™, was used for planar Ti coupons as instructed. After careful rinsing and drying, four experimental silane primers were applied onto silica-coated Ti specimens. The primers were prepared of 3-acryloxypropyltrimethoxysilane + bis-1,2-(triethoxysilyl)ethane (in four concentrations), diluted in acidified ethanol-water. The contact angles, surface free energies, and critical surface tensions were assessed. The chemical compositions of surfaces were analyzed using X-photoelectron spectroscopy. Atomic force microscopy was used to investigate the surface topographies. Non-treated Ti specimens and silanized with a commercial silane primer were used as the controls.

RESULTS

There were observable differences in the surface free energy (contact angle) and chemical composition on specimens. The silane primers reacted and fully covered Ti surfaces, which produced more hydrophobic coatings, larger contact angles, and lower surface free energy and critical surface tension than controls. At the concentration of 1.0 vol% 3-acryloxypropyltrimethoxysilane and 0.3 vol% bis-1,2-(triethoxysilyl)ethane, the silane blend showed the lowest surface free energy. The silanes would not affect the surface roughness (P > 0.05).

CONCLUSIONS

Novel coatings were successfully developed and optimized. They may produce a hydrophobic surface onto Ti implants without compromising the surface roughness.

Shear bond strength of rebonded brackets after removal of adhesives with Er,Cr:YSGG laser

This study was conducted to examine the bond strength of rebonded orthodontic brackets after adhesive residuals on the surface of the bracket bases were removed by Er,Cr:YSGG lasers. Seventy-six brackets bonded to premolars with a self-etching primer adhesive system were equally divided into four groups after the first debonding with the bracket bases (Group 1) untreated, and treated by (Group 2) Er,Cr:YSGG laser, (Group 3) sandblaster, and (Group 4) Er,Cr:YSGG laser/sandblaster. The treated brackets were rebonded to the new premolars in the same manner as the first-stage experiment. The shear bond strengths were measured, with the bonding/debonding procedures repeated once after the first debonding, and the bracket/adhesive failure modes were evaluated after each debonding. The treated bracket base surfaces were observed under a scanning electron microscopy (SEM). The mean rebond strengths were significantly lower in group 1 than in other groups, and there were no significant differences between the other groups. The mean initial bond strength was significantly higher than the mean rebond strength in group 1 but there was no significant difference between the two in the other three groups. Failures at the bracket-adhesive interface occurred frequently at second debonding in group 1. Under the SEM, residual adhesive was removed from the bracket bases by Er,Cr:YSGG laser, while adhesive remnant was seen underneath the meshwork of the bracket bases and microroughness appeared on the meshwork after sandblasting. Er,Cr:YSGG laser certainly could serve the purpose of promoting the use of recycled orthodontic brackets.

Effect of ZrN coating by magnetron sputtering and sol-gel processed silica coating on titanium/porcelain interface bond strength

In this study, a coating technique was applied to improve the bond strength of titanium (Ti) porcelain. ZrN coating was prepared by magnetron sputtering, and silica coating was processed by a sol-gel method. The treated surfaces of the specimens were analyzed by X-ray diffraction, and the Ti/porcelain interface was investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy. The coated specimens appeared fully coherent to the Ti substrate. The fractured bonding surface was also investigated by SEM. The residual porcelain on the metal surface could be observed in the ZrN group and silica group, but there was no obvious porcelain remaining in the control group. A three-point-bending test showed that the bonding strength of the ZrN group (45.99 ± 0.65 MPa) was higher than the silica group (37.77 ± 0.78 MPa) (P < 0.001) and control group (29.48 ± 1.01 MPa) (P < 0.001), while that of the silica group was significantly higher than the control group (P < 0.001). In conclusion, conditioning the ceramic surface with ZrN and silica coatings resulted in a stronger Ti/porcelain bond. ZrN coating by magnetron sputtering was a more effective way to improve the bond strength between Ti and porcelain compared with sol-gel processed silica coating in this study.

Effect of surface treatments on the bond strength of a resin cement to commercially pure titanium

Investigation of the effectiveness of surface treatments that promote a strong bond strength of resin cements to metals can contribute significantly to the longevity of metal-ceramic restorations. This study evaluated the effect of surface treatments on the shear bond strength (SBS) of a resin cement to commercially pure titanium (CP Ti). Ninety cast CP Ti discs were divided into 3 groups (n=30), which received one of the following airborne-particle abrasion conditions: (1) 50 ?m Al2O3 particles; (2) 30 ?m silica-modified Al2O3 particles (Cojet Sand); (3) 110 ?m silica-modified Al2O3 particles (Rocatec). For each airborne-particle abrasion condition, the following post-airborne-particle abrasion treatments were used (n=10): (1) none; (2) adhesive Adper Single Bond 2; (3) silane RelyX Ceramic Primer. RelyX ARC resin cement was bonded to CP Ti surfaces. All specimens were thermally cycled before being tested in shear mode. Failure mode was determined. The best association was Rocatec plus silane. All groups showed 100% adhesive failure. There were combinations that promote higher SBS than the protocol recommended by the manufacturer of RelyX ARC.

Durability of the bond between resin composite cores and prefabricated posts

OBJECTIVES

This study evaluated the effect of post surface treatment and of storage condition on the bond between resin composite cores (Clearfil Core) and posts of titanium alloy (Fysika), silica-zircon fiber reinforced epoxy resin (SiliciumPost), and zirconia (CosmoPost).

MATERIAL AND METHODS

In the experimental groups, the coronal part of each post received sandblasting or tribochemical silicate-coating (CoJet) treatment. The coronal part of each post was embedded in a cylinder of resin composite core material with the aid of a fixation apparatus. After 15 min, the specimen was freed from the mold and stored in de-ionized water. The axial tensile strength (ATS) of posts was determined in a Universal Testing Machine when extracting the posts from the resin composite cores after: 1) 14 d water storage at 37°C, 2) 14 d water storage at 37°C followed by thermal cycling (6,000 cycles between 5°C and 55°C), or 3) 1 year water storage at 37°C. The results were statistically analyzed by three-way factorial ANOVA and Newman-Keuls' multiple range test.

RESULTS

The ATS values were generally higher for Fysika posts and SiliciumPost posts than for CosmoPost posts. Surface treatment effectively improved the ATS values of Fysika posts and SiliciumPost posts, but not those of CosmoPost posts. Thermal cycling or long-term water storage had only minimal effect on the ATS values of the posts.

CONCLUSION

Bonding of resin composite cores to the posts depended more on the material of the post and the surface treatment of posts than on the storage condition.

Bone cell responses of titanium blasted with bioactive glass particles

Surface modification of Ti-based metals is an important issue in improving the bone cell responses and bone-implant integration. Blasting Ti with granules (mostly alumina) is commonly used to prepare a clean surface and provide a level of roughness. In this study, glass granules with a bioactive composition were used as the blasting source to improve the surface bioactivity and biocompatibility of a Ti substrate. Bioactive glass particles with a composition of 70SiO(2) * 25CaO * 5P(2)O(5) were prepared using a sol-gel method. A Ti disc was blasted with glass particles using a dental blasting unit (BG-Ti). A Ti disc blasted with commercial spherical-shaped glass (G-Ti) and a disc without blasting (Ti) were also prepared for comparison. The blasted Ti contained a large number of glass particles after the blasting process. The surface roughness of the samples in ascending order was G-Ti>BG-Ti>Ti. Murine-derived preosteoblasts (MC3T3-E1) were seeded on the samples, and the cell growth, differentiation, and mineralization behaviors were observed. The osteoblastic cells attached well and spread actively over all the sample groups with extensive cytoskeletal processes. The level of cell growth on the BG-Ti showed a continual increase with culturing up to 7 days, showing good cell viability. However, there was no significant difference (ANOVA, p<0.05) with respect to the G-Ti and Ti groups. In particular, the alkaline phosphatase (AP) activity of the cells was significantly higher on the BG-Ti than on the other groups after culturing for 14 days. Moreover, the mineralization behavior of the cells, as assessed by Alizarin S Red, was superior on the BG-Ti to that observed on the other groups after culturing for 14 and 28 days. Overall, the blasting of Ti with a bioactive glass composition is considered beneficial for producing substrates with enhanced osteogenic potential.

Effect of metal primers on bond strength of resin cements to base metals

STATEMENT OF PROBLEM

A strong and durable bond between a metal framework and a resin-based luting agent is desired. Metal primers have been shown to be very effective on noble alloys. However, there is insufficient information about their effect on base metals.

PURPOSE

The purpose of this study was to evaluate the effect of metal primers on the shear bond strength of resin cements to base metals.

MATERIAL AND METHODS

A total of 160 cast commercially pure titanium (CP Ti) and NiCr alloy (VeraBond II) disks were embedded in a polyvinyl chloride ring, and their surfaces were smoothed with silicon carbide papers (320, 400, and 600 grit) and airborne-particle abraded with 50-mum aluminum oxide. Specimens of each metal were divided into 4 groups (n=20), which received one of the following luting techniques: (1) Panavia F, (2) Alloy Primer plus Panavia F, (3) Bistite II DC, or (4) Metaltite plus Bistite II DC. Forty minutes after preparation, all specimens were stored in distilled water at 37 degrees C for 24 hours and then thermal cycled (1000 cycles, 5-55 degrees C). After thermal cycling, the specimens were stored in 37 degrees C distilled water for an additional 24 hours or 6 months before being tested in shear mode. Data (MPa) were analyzed using 3-way ANOVA and the post hoc Tukey test (alpha=.05). Each specimen was examined under an optical microscope (x30), and the failure mode was classified as adhesive, cohesive, or a combination of these.

RESULTS

The only significant difference between the Panavia F and Alloy Primer plus Panavia F groups occurred in the NiCr alloy at 24 hours, at which point Panavia F demonstrated superior bond strength compared to Alloy Primer plus Panavia F (P<.001). The Bistite II DC and Metaltite plus Bistite II DC groups were not significantly different. The Bistite II DC and Metaltite plus Bistite II DC groups demonstrated significantly lower bond strength to CP Ti (P<.001) than the Panavia F and Alloy Primer plus Panavia F groups, and significantly lower bond strength to NiCr alloy (P<.001) than Panavia F. The Panavia F (P<.01) and Alloy Primer plus Panavia F groups' bond strength to titanium presented a significant increase (P<.001) in shear bond strength at 6 months. In general, the groups exhibited higher shear bond strength to CP Ti than to NiCr alloy (P<.01). The failure mode was 100% adhesive for all groups.

CONCLUSIONS

The metal primers did not promote an increase in adhesive bonding of resin cements to NiCr alloy and to CP Ti. Water storage had no adverse effect on the shear bond strength of the groups. The shear bond strengths to titanium were significantly higher than those to the NiCr alloy.

Adhesive bonding of resin composite to various Ni-Cr alloy surfaces using different metal conditioners and a surface modification system

PURPOSE

This study evaluated the effect of three metal conditioners [Metal Photo Primer (MPP), Cesead II Opaque Primer (OP), Targis Link (TL)], and one surface modification system [Siloc (S)] on the shear bond strength (SBS) of a prosthetic composite material to Ni-Cr alloy.

MATERIALS AND METHODS

Rivet-shaped specimens were cast, and three surface treatments were evaluated: Polishing (P); sandblasting with either 50 microm (50SB) or 250 microm (250SB) Al(2)O(3). All products were applied to half of the specimens, while the other half remained without the materials. Veneering resin composite (8-mm diameter, 2-mm thick) was applied and light-exposed for 90 seconds in a laboratory light-curing unit. The specimens were stored in water at 37 degrees C for 24 hours, and half were subjected to 500 thermal cycles consisting of water baths at 4 degrees C and 60 degrees C. All specimens were submitted to SBS test (0.5 mm/min) until failure. Failure patterns were determined using optical and scanning electron microscope (SEM) analysis. Data were analyzed by ANOVA and post hoc Tukey's test (preset alpha of 5%).

RESULTS

The SBS values of OP and TL groups were higher than those of MPP and S within the 50SB treatment (p < 0.05). No significant difference in SBS was noted between OP and TL as well as between MPP and S. On the other hand, no significant differences were found among conditioners within the 250SB group (p > 0.05). The SBS values of MPP, OP, and S from the 250SB group were higher than those from 50SB (p < 0.05). No significant difference in SBS was noted among most groups with conditioners after thermocycling. The only exception was observed for MPP, which showed an increase in SBS after thermocycling (p < 0.05). Differences in SBS were noted among the groups with conditioners (p < 0.05), and no significant difference in SBS was noted between TL and OP groups, which showed the highest values among all within the P group. No significant difference was noted between MPP and S. Debonded surfaces showed adhesive failures predominantly located between metal surface and opaque resin.

CONCLUSIONS

The OP and TL conditioners and surface sandblasting with 250 microm Al(2)O(3) promoted the highest SBS between resin and the Ni-Cr metal surface.

Effect of the cross-linking silane concentration in a novel silane system on bonding resin-composite cement

OBJECTIVE

Four experimental blends of an organo-functional silane monomer with a non-functional cross-linking silane monomer (a novel silane system) were evaluated as adhesion promoters in an experiment in which a resin-composite cement was bonded to silica-coated titanium.

MATERIAL AND METHODS

3-Acryloyloxypropyltrimethoxysilane (as constant 1.0 vol%) was blended with 1,2-bis-(triethoxysilyl)ethane, where its concentration was 0.1, 0.2, 0.3, or 0.5 vol%. Titanium slides (n=20) were grit-blasted, silica-coated, and silanized with four experimental silane solutions, with a pre-activated silane Cimaratrade mark (VOCO, Germany) as control. After silanization, resin-composite cement stubs (Bifixtrade mark QM; VOCO, Germany) were photo-polymerized. The shear bond strength was measured after dry storage (24 h) or after thermo-cycling (6000 cycles between 5 degrees C and 55 degrees C). The resin stub failure mode was determined.

RESULTS

Statistical analysis (ANOVA) showed that type of storage (p <0.05) and concentration of cross-linker silane (p<0.005) both significantly affected the shear bond strength. The highest shear bond strength was obtained with a blend of 1.0 vol% 3-acryloyloxypropyltrimethoxysilane+0.3 vol% 1,2-bis-(triethoxysilyl)ethane, 15.9 MPa (standard deviation SD 3.4 MPa) for both the thermo-cycled group and after dry storage (24 h), 14.3 MPa (SD 4.1 MPa) (n=8/group). The lowest values were obtained with Cimaratrade mark silane 7.3 MPa (SD 2.2 MPa) in dry storage and 7.9 MPa (SD 2.0 MPa) obtained with 1.0 vol% 3-acryloyloxypropyltrimethoxysilane+0.1 vol% 1,2-bis-(triethoxysilyl)ethane. The failure type was mainly cohesive.

CONCLUSION

A novel silane system with an optimal concentration of the cross-linking silane may produce significantly higher shear bond strength between silica-coated titanium and resin-composite cement compared to a pre-activated silane product.