Effect of sulfuric acid etching of polyetheretherketone on the shear bond strength to resin cements

Effect of surface treatment and resin cement type on the bond strength of polyetheretherketone to lithium disilicate ceramic

BACKGROUND

This study aims to evaluate the effect of surface treatment and resin cement on the shear bond strength (SBS) and mode of failure of polyetheretherketone (PEEK) to lithium disilicate ceramic (LDC). This is suggested to study alternative veneering of PEEK frameworks with a ceramic material.

METHODS

eighty discs were prepared from PEEK blank and from lithium disilicate ceramic. Samples were divided into four groups according to surface treatment: Group (A) air abraded with 110 μm Al2O3, Group (AP) air abrasion and primer application, Group (S) 98% sulfuric acid etching for 60 s, Group (SP) Sulfuric acid and primer. Each group was subdivided into two subgroups based on resin cement type used for bonding LDC:1) subgroup (L) self- adhesive resin cement and 2) subgroup (B) conventional resin cement (n = 10). Thermocycling was done for all samples. The bond strength was assessed using the shear bond strength test (SBS). Failure mode analysis was done at 50X magnification with a stereomicroscope. Samples were chosen from each group for scanning electron microscope (SEM). The three-way nested ANOVA followed by Tukey's post hoc test were used for statistical analysis of results. Comparisons of effects were done utilizing one way ANOVA and (p < 0.05).

RESULTS

The highest mean of shear bond strength values was demonstrated in Group of air abrasion with primer application using conventional resin cement (APB) (12.21 ± 2.14 MPa). Sulfuric acid groups showed lower shear bond strength values and the majority failed in thermocycling especially when no primer was applied. The failure mode analysis showed that the predominant failure type was adhesive failure between cement and PEEK, while the remaining was mixed failure between cement and PEEK.

CONCLUSION

The air abrasion followed by primer application and conventional resin cement used for bonding Lithium Disilicate to PEEK achieved the best bond strength. Primer application did not have an effect when self-adhesive resin cement was used in air-abraded groups. Priming step is mandatory whenever sulfuric acid etching surface treatment is utilized for PEEK.

Improving Surface Properties of PEEK for Dental Applications by Using Piranha Solution

Background

"Polyetheretherketone (PEEK)" is a biocompatible, high-strength polymer that is well-suited for use in dental applications due to its unique properties. However, achieving good adhesion between PEEK and hydrophilic materials such as dental adhesives or cement can be challenging. Also, this hydrophobicity may affect the use of PEEK as an implant material. Surface treatment or conditioning is often necessary to improve surface properties. The piranha solution is the treatment of choice to be explored for this purpose.

Methods

PEEK disks of 10 mm diameter and 2 mm thickness were used in this study. Those samples were divided into five groups (each group has five samples). The first is the control group, in which no acid treatment was used; the second group undergoes sulfuric acid treatment. The remaining three groups were treated with Piranha solution; each group used a different concentration (1 : 3, 1 : 5, and 1 : 7 hydrogen peroxide to sulfuric acid, respectively). The period of treatment was 60 s for all groups. Wettability and surface roughness tests were done for the five groups. In statistical analysis, Shapiro-Wilk test was used to check the assumption of normality and to determine the statistical significance among groups; a one-way analysis of variance was employed. Subsequently, for multiple comparisons, Tukey's honestly significant difference post hoc test was performed.

Results

The Piranha solution treatment groups showed a higher wettability compared to the control group and the group treated with sulfuric acid. Additionally, the Piranha solution treatment with a higher concentration of hydrogen peroxide (1 : 3) resulted in greater improvement in surface roughness compared to the control group and the lower concentration groups (1 : 5 and 1 : 7), while the sulfuric acid treated group showed the highest surface roughness.

Conclusion

The results of this study suggest that the piranha solution can be an effective method for improving the surface characteristics of PEEK to be used in different dental applications, especially as a dental implant material, due to the increase in wettability and surface roughness.

Comparison of tensile bond strength of ball attachments made of different materials to root canal dentin after chewing simulation

BACKGROUND

Debonding of ball attachments is one of the complications that annoy teeth supported overdenture wearers. The polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) polymers are widely applied in the dental field. The purpose of the current study was to compare the tensile bond strength of ball attachments made of such materials and the commonly used titanium ones after 5 years of overdenture insertion and removal (5000 cycles) in addition to chewing simulation (1,200,000 cycle).

METHODS

Extracted mandibular canines (N = 60) were randomly allocated into three groups and received ball attachments; titanium (group TI; N = 20), PEEK (group PE; N = 20), PEKK (group PK; N = 20). In each group, the samples were divided into two subgroups whereas tensile bond strength was measured pre aging (T0; n = 10) and post aging (T1; n = 10). Tensile bond strength was measured by the Pull out test using the Universal testing machine. Failure mode analysis was determined by examination of the samples' surfaces under 65X stereomicroscope. The resulting data followed normal distribution and the significance level was set at (α = 0.05).

RESULTS

One Way Anova showed statistically significant difference between the three groups (P < .00001). PostHoc Tukey test showed statistically significant difference between the groups TI and PE, TI and PK and no statistically significant difference between the groups PE and PK. Paired t test showed statistically significant difference in the tensile bond strength pre and post aging in each group.

CONCLUSIONS

PEEK and PEKK ball attachments could be concluded to have a higher tensile bond strength compared to the titanium ones when bonded to root dentin. Tensile bond strength of such attachments may decrease with aging as well. Clinically, the higher tensile bond strength may have a lesser rate of debonding and thus reduced patient apprehension.

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.

Assessment of different surface treatments and shear bond characteristics of poly-ether-ether-ketone: An in vitro SEM analysis

Aim:

The aim of this study is to assess the surface roughness and shear bond characteristics of pol-ether-ether-ketone after different surface treatments.

Setting and Design:

An in vitro, prospective.

Materials and Methods:

One hundred and twenty disc-shaped samples of 10 mm diameter and 2 mm thickness were milled and subjected to following surface treatments: 110 μm alumina particles, 98% concentrated sulfuric acid, and 10–20 μm synthetic diamond particles. Surface characteristics of treated sample were studied under SEM with ×500 and ×1000 magnification. Shear bond strength (SBS) with composite resin discs embedded in acrylic blocks after luting with self-etch resin cement and resin-modified glass ionomer cement (RMGIC) was evaluated using the universal testing machine (Instron®, Massachusetts U. S. A).

Statistical Analysis Used:

The data collected were evaluated using the Analysis of variance and Tukey's honest significant difference post hoc test.

Results:

Highest SBS and SR were noted with self-etch resin cement in the given order: 98% sulfuric acid (2.106 ± 0.186 μm), followed by alumina particles (1.706 ± 0.160 μm) and synthetic diamond particles (1.101 ± 0.167 μm).

Conclusion:

The SBS of self-etch resin cement was higher compared to RMGIC for all three surface treatments done on test samples. Hundred percent samples treated by all three surface treatment methods showed mixed type of failure.

Effect of Acid-Etching Duration on the Adhesive Performance of Printed Polyetheretherketone to Veneering Resin

Three-dimensional printing polyetheretherketone (PEEK) provides a new choice for dental prostheses, while its appropriate bonding procedure and adhesive performance are still unclear. This study aimed to investigate the adhesive performance of printed polyetheretherketone (PEEK) after acid etching to veneering resin. In total, 182 PEEK specimens (including 91 printed and 91 milled specimens) were distributed to 14 subgroups (n = 13/subgroup), according to the manufacturing process and surface treatment. The specimens were polished and etched with sulfuric acid for 0, 5, 30, 60, 90, 120, and 300 s, respectively. Two specimens in each subgroup were observed under a scanning electron microscope (SEM) for surface and cross-section morphology separately. Then, the specimens were treated with a bonding primer, and one specimen in each subgroup was prepared for cross-sectional observation under SEM. The residual 10 specimens of each subgroup bonded with veneering resin were tested with the shear bond strength tests (SBS) and failure modes analysis. Statistical analysis was performed by one-way ANOVA followed by the SNK-q post hoc test (p < 0.05). The etched pores on the PEEK surface were broadened and deepened under SEM over time. Printed PEEK etched for 30 s obtained the best SBS-to-veneering-resin ratio (27.90 ± 3.48 MPa) among the printed subgroups (p < 0.05) and had no statistical differences compared with milled PEEK etched for 30 s. The SBS of the milled subgroups etched from 5 to 120 s were over 29 MPa without significant between-group statistical differences. Hence, printed PEEK can be coarsened effectively by 30 s of sulfuric acid etching. The adhesion efficacy of printed PEEK to veneering resin was qualified for clinical requirements of polymer-based fixed dentures.

Surface Morphology and Mechanical Properties of Polyether Ether Ketone (PEEK) Nanocomposites Reinforced by Nano-Sized Silica (SiO2) for Prosthodontics and Restorative Dentistry

In the field of orthopedics and traumatology, polyether ether ketone (PEEK) serves a significant role as a suitable alternative to traditional metal-based implants like titanium. PEEK is being used more commonly to replace traditional dental products. For bonding with various adhesive agents and preserved teeth, the surface alteration of PEEK was investigated. The aim of this research was to understand how different types and contents of nano-sized silica (SiO2) fillers influenced the surface and mechanical properties of PEEK nanocomposites used in prosthodontics. In this work, PEEK based nanocomposites containing hydrophilic or hydrophobic nano-silica were prepared by a compression molding technique. The influence of nano-SiO2 type and content (10, 20 and 30% wt) on surface properties of the resultant nanocomposites was investigated by the use of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness analysis, and contact angle measurement. The crystalline structures of PEEK/SiO2 nanocomposites were examined by X-ray diffraction (XRD) spectroscopy. Mechanical properties were measured by microhardness, elastic compression modulus, and flexural strength. All nanocomposites showed increased surface roughness compared to pure PEEK. SEM images revealed that nanocomposites filled with low content hydrophobic nano-SiO2 showed uniform dispersion within the PEEK matrix. The introduction of 10 wt% of hydrophobic nano-SiO2 to the PEEK matrix improved elastic modulus, flexural strength, and microhardness, according to the findings. The addition of nano-SiO2 fillers in a higher weight percentage, over 10%, significantly damages the mechanical characteristics of the resultant nanocomposite. On the basis of the obtained results, PEEK/SiO2 nanocomposites loaded with low content hydrophobic nano-SiO2 are recommended as promising candidates for orthopedic and prosthodontics materials.

Effect of Surface Treatment With Er:YAG and CO2 Lasers on Shear Bond Strength of Polyether Ether Ketone to Composite Resin Veneers

Introduction: Polyether ether ketone (PEEK) has low surface energy and high resistance to chemical surface treatments. Therefore, different surface treatments such as laser conditioning should be investigated. There is a gap of information regarding the efficacy of laser irradiation in the surface treatment of PEEK, and the efficacy of several laser types needs to be evaluated for this purpose. This study aimed to assess the effect of surface treatment with erbium-doped yttrium aluminum garnet (Er:YAG) and carbon dioxide (CO2) lasers on shear bond strength (SBS) of PEEK to composite resin veneers. Methods: In this experimental study, 60 rectangular-shaped PEEK samples (7 x 7 x 2 mm) were used. The samples were mounted in auto-polymerizing acrylic resin in such a way that only one surface measuring 7x7 mm remained exposed. The samples were then randomly divided into 3 groups (n=20) of control, Er:YAG laser surface treatment (Power=1.5 W, energy density=119.42 J/cm² , irradiation time=20 s) and CO2 laser surface treatment (Power=4 W, energy density=159.22 J/cm² , irradiation time=50 s). The bonding agent and PEEK opaque were applied on the surface of samples and they were veneered with a composite resin using a hollow plastic cylinder with an internal diameter of 4 mm. The SBS was then measured and the data were analyzed using one-way ANOVA, Tukey HSD test and Dunnett's test at 0.05 level of significance. Results: The SBS of the 3 groups was significantly different (P<0.001). The Tukey HSD test revealed that the Er:YAG laser had higher SBS than the CO2 laser group (P<0.001). The Dunnett's test showed that both Er:YAG and CO2 laser groups yielded higher SBS than the control group (P<0.001). Conclusion: The Er:YAG and CO2 laser treatments can increase the SBS of PEEK to composite resin veneers, although the Er:YAG laser seems to be more effective for this purpose.

Effect of Surface Treatments on Shear Bond Strength of Polyetheretherketone to Autopolymerizing Resin

These days, new prosthodontic materials are appearing with the development of digitalization. Among these, the use of polyetheretherketone (PEEK) as the clasp of removable partial dentures has been proposed. The adhesive strength between the PEEK and acrylic resin influences the probability of denture fracture. To investigate the effect of PEEK surface treatments on the shear bond strength to acrylic resin, five surface treatment conditions of PEEK were analyzed: 1. no treatment; 2. ceramic primer application; 3. Al₂O₃ sandblasting; 4. Rocatec; and 5. Rocatec with ceramic primer application, comparing with a metal primer-treated Co-Cr alloy. Two kinds of autopolymerizing resin (Unifast II and Palapress Vario) were used as bonding materials. The specimens were evaluated to determine the bond strength. Rocatec treatment with ceramic primer application yielded the highest bond strengths (12.71 MPa and 15.32 MPa, respectively, for Unifast II and Palapress Vario). When compared to a metal primer-treated Co-Cr alloy, the bond strength of PEEK to Unifast II was similar, whereas it was about 60% of that to Palapress Vario. Rocatec treatment, combined with ceramic primer, showed the highest bond strength of PEEK to acrylic resin. Treatment of PEEK will enable its use as the clasp of removable dentures and the fixation of PEEK prostheses.

The Effect of Various Plasma Gases on the Shear Bond Strength between Unfilled Polyetheretherketone (PEEK) and Veneering Composite Following Artificial Aging

This study investigated the effect of different gaseous plasma surface treatments on the shear bond strength between unfilled polyetheretherketone (PEEK) and veneering composite resin. The study followed ISO 10477 guidelines in preparing, bonding, and testing the samples. Specimens of unfilled PEEK were distributed to one of the following six surface treatment groups: reference, adhesive, argon, nitrogen, oxygen, and air plasmas. After milling, the specimens were wet polished using (P320) polishing discs. Bonding procedures were done according to the manufacturer's instructions using (Opaquer + Dentine), except in the adhesive group (Visio.link + Opaquer + Dentine). Afterwards, thermal cycling for 5000 cycles between 5 and 55 °C in distilled water was conducted. Finally, the shear bond strengths of all groups were calculated, and mode of fracture was determined. Nitrogen surface treatment had the highest mean shear bond strength of 10.04 (±1.84) MPa, while the reference group showed the lowest value of 5.38 (±2.90) MPa. Regarding mode of fracture, all the specimens showed a 100% adhesive failure mode. Plasma surface treatment can be a reliable alternative method to the traditional protocol of bonding veneering composite resin to unfilled PEEK material.

Effect of non-thermal plasma on the shear bond strength of resin cements to Polyetherketoneketone (PEKK)

PURPOSE

This study aimed to assess the effect of non-thermal plasma on the shear bond strength of resin cements to polyetherketoneketone (PEKK) in comparison to other surface treatment methods.

MATERIALS AND METHODS

Eighty PEKK discs were subjected to different surface treatments: (1) Untreated (UT); (2) Non-thermal plasma (NTP); (3) Sandblasting with 50 µm Al₂O₃ particles (SB); and (4) Sandblasting + Non-thermal plasma (SB+NTP). After each surface treatment, the contact angle was measured. Surface conditioning with Visio.Link was applied in all groups after pre-treatment. RelyX Unicem resin cement was bonded onto the PEKK specimens. After fabrication of the specimens, half of each group (n=10) was initially tested, while the other half was subjected to thermocycling (5℃ to 55℃ at 10,000 cycles). Shear bond strength (SBS) testing was performed using a universal testing machine, and failure modes were assessed using stereomicroscopy. The SBS results were analyzed statistically using one-way ANOVA followed by Tukey's post hoc test. Independent t-test was used to examine the effect of thermocycling (P<.05).

RESULTS

The highest SBS values with or without thermocycling were observed with PEKK specimens that were treated with SB+NTP followed by the SB group. The lowest SBS results were observed in the UT groups.

CONCLUSION

The shear bond strength between PEKK and resin cements was improved using non-thermal plasma treatment in combination with sandblasting.

Effects of sulfuric and vinyl sulfonic acid etchants on bond strength of resin composite to polyetherketoneketone

This study aims to evaluate the effects of etching with sulfuric acid (SA) and vinyl sulfonic acid (VSA) on the bond strength between a light-curing indirect resin composite and polyetherketoneketones (PEKK). PEKK specimens were ground with 600 silicon carbide papers, etched with 90% SA for 5 s (90-5 SA) or 95% VSA for 30 s (95-30 VSA), and then modified with a phosphate primer; afterward, a light-curing resin composite was veneered on the specimens. Two control groups were also prepared without etching (unetched/unprimed and unetched/primed). After 20,000 thermocycles in water at 4 and 60 °C, the shear bond strengths of the specimens were determined and subjected to a nonparametric (Steel-Dwass) test (α = 0.05, n = 8). The etched surfaces were observed by scanning electron microscopy (SEM) at 2000× magnification. Higher bond strengths were obtained when the PEKK surface was etched with 90-5 SA or 95-30 VSA (90-5 SA/unprimed 24.3 ± 4.3 MPa, 90-5 SA/primed 26.2 ± 3.2 MPa, 95-30 VSA/unprimed 23.7 ± 2.5 MPa, 95-30 VSA/primed 24.3 ± 4.1 MPa), and these values were not statistically different, whereas the two control groups exhibited significantly lower bond strengths (unetched/unprimed 12.2 ± 1.7 MPa, unetched/primed 9.5 ± 2.7 MPa). SEM observations revealed that 95-30 VSA led to a microporous (felt-like) surface, which was different from the surface structure etched with 90-5 SA. Etching the PEKK surface with SA or VSA significantly improved the bond strength between resin composite and PEKK in contrast with the application of the phosphate primer. Appropriate chemical etching could be a useful option when fabricating prostheses using PEKK-based materials and indirect resin composites.