This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The traditional metal-ceramic technique has been documented to be a reliable clinical application... more The traditional metal-ceramic technique has been documented to be a reliable clinical application. However, ceramic restorative materials have gained popularity in recent years. 1 These can be categorized into glass-matrix ceramics, polycrystalline ceramics, and resin-matrix ceramics. 2 Glass-matrix ceramics have an extensive history of application in dentistry as their chemical composition has a high amount of silica, making the material highly translucent, biomimetic, and biocompatible. 3 Advances in material properties have broadened the application of glass ceramics. The inherent brittleness and low fracture resistance of glass ceramics were improved either by incorporating reinforcing materials such as leucite or by the application of new materials, including lithium disilicate (LD). 3,4 With the launch of IPS Empress 2 in 1998 and IPS e.max Press in 2005, LD glass ceramics provided dentists with a ceramic with enhanced mechanical properties and natural appearance. With the flexural strength of over 300 MPa,
To evaluate the light transmission effects on the enclosed mold shear bond strength (EM-SBS) of r... more To evaluate the light transmission effects on the enclosed mold shear bond strength (EM-SBS) of resin-Ti covered with various hybrid CAD/CAM ceramics in different thickness. Materials and methods: Three CAD/CAM hybrid ceramics, Lava Ultimate TM , Cerasmart TM and Vita TM Enamic were cut into specimens with a size of 0.2 mm × 0.5 mm and thickness 0.2-1.0 mm. Ti sheets were cut, grit blasted and silanized with Monobond ® Plus. Polypropylene molds (2 mm in height) were used for resin stub preparation using Multilink ® Automix resin composite cement. An external mold was prepared to cover every sample and to make sure light only passes through ceramic. EM-SBS was measured using a universal testing machine. Results: Resin-Ti bonding cured under Lava Ultimate TM , showed higher EM-SBS than Cerasmart TM and Vita TM Enamic. The EM-SBS decreased with increasing thickness of each ceramic from 0.2 to1.0 mm. SEM, AFM and surface roughness profilometer showed surface roughness for Lava Ultimate TM , and Cerasmart TM was decreased after polishing and for Vita TM Enamic it was slightly increased. Conclusions: Resin-Ti bonding cured under Lava Ultimate TM , showed higher EM-SBS than Cerasmart TM and Vita TM Enamic. The EM-SBS decreased with increasing thickness of each ceramic from 0.2 to1.0 mm. SEM, AFM and surface roughness profilometer showed surface roughness for Lava Ultimate TM , and Cerasmart TM was decreased after polishing and for Vita TM Enamic it was slightly increased.
Background: The aim of the study was to investigate whether the citric acid and rough surface hav... more Background: The aim of the study was to investigate whether the citric acid and rough surface have a synergistic effect leading to severe wear behavior of resin composite. Materials and methods: Disk-shaped (Ø15 × 1.5 mm) specimens of resin composite (n = 12) with different initial roughness were prepared. Reciprocating ball-on-flat wear tests were performed under distilled water and citric acid (pH = 5.5) respectively. The coefficient of friction (COF), wear volume loss, and duration of the running-in period were quantified to assess the wear performance. And the values were analyzed with one-way ANOVA (α = 0.05). Regression analysis was applied to examine the influence of Ra values and mediums on the wear data. The wear morphology was analyzed by scanning electron microscopy and a 3D profilometer. Results: The average COF was higher in distilled water than in citric acid but was independent of the surface roughness. For the composite, the volume loss of worn area and running-in period increased with surface roughness when tested under distilled water. However, these increasing trends were not found in citric acid. All specimens exhibited mild wear behavior with low COF and less superficial abrasion in acidic medium. Conclusions: The effect of initial roughness on wear behavior depends on the medium. In distilled water, resin composites with high initial roughness exhibit a longer running-in time, which eventually leads to a significant increase in material loss. The adverse effects of high roughness can be alleviated by the lubrication of citric acid, which can maintain a mild wear behavior regardless of initial surface roughness.
Midpalatal suture was analysed with cone beam computed tomography to identify its maturation with... more Midpalatal suture was analysed with cone beam computed tomography to identify its maturation with respect to age and maxillary-complex growth in 72 patients 9-to 21-year-old. Maxillary-complex was divided in premaxillary, maxillary, and palatine segment. Interdigitation and ossification of midpalatal suture, its density relative to hard tissues and soft tissues, and midpalatal suture density ratio were measured for each segment. Correlation of each parameter with age and maxillarycomplex length was analysed, and classification trees were developed for staging parameters. Midpalatal suture maturation stages (MPSMS, from A to E) were applied to assess relationship with age and maxillary-complex length. Regarding age, ossification increased in maxillary segment of males (r S = 0.39, p = 0.032), while suture density relative to soft tissues increased in maxillary (r S = 0.37, p = 0.042) and palatine segments (r S = 0.41, p = 0.027) of males and in palatine segment of females (r S = 0.32, p = 0.041). In males, suture density relative to soft tissues discriminated two age-stages (p = 0.024), and the same parameter (p = 0.023) paired with ossification (p = 0.027) discriminated two length-stages. MPSMS identified length-differences between stage A and B in females (p = 0.001). Midpalatal-suture ossification and its density relative to soft tissues showed some relationship with age and maxillary-complex length, especially in males. However, challenging staging and limitations in the imaging method may limit clinical applications. Skeletal maturation refers to changes including shape modifications 1 , ossification of elements 2 , and density variations 3. Although longitudinal size measurements provide valid growth representations 1 , they have limited predictive value when applied to cross-sectional assessment of individuals 4. Thus, maturational assessments based on stages have been developed 1. Despite assessment of the overall skeletal maturational may be valid for facial growth as well 4 , maxillary growth differs from mandibular growth and may deserve a specific assessment 5 , with the midpalatal suture having been proposed as a suitable structure for such purpose 6. Differences in some midpalatal suture parameters have been reported from puberty to adulthood 7-9 , providing the rationale for a possible maturational assessment. A first parameter is the interdigitation i.e., the ratio between the suture length and the distance between its beginning and end 10 , exhibiting the change from a flat interface in infancy to an interdigitated structure in adolescence 7. A second one is the ossification i.e., the ratio between the ossified suture length and the suture length 9,10 , expressing the "fusion" that the suture begins during adolescence and that proceeds towards adulthood 9. A third one is the density ratio i.e., the ratio between the grey density of the suture and a reference area 11 , representing both the increase in bone mineral density that happens during skeletal maturation 3 and the sutural ligament ossification 9. This said, the maxillary-complex is
Numerous approaches have been developed to improve the resin-dentin bond performance, among which... more Numerous approaches have been developed to improve the resin-dentin bond performance, among which the bio-application of mussel-derived compounds have drawn great attention recently. To assess the performance of N-(3,4-dihydroxyphenethyl)methacrylamide (DMA), a mussel-derived compound, as a functional monomer in dental adhesive, its potential property to cross-link with dentin collagen and polymerize with adhesive will first be evaluated by transmission electron microscopy (TEM), attenuated total reflectance technique of Fourier transform infrared (ATR-FTIR), and atomic force microscopy (AFM) via Peakforce QNM mode. After validating the influence of DMA on collagen and adhesive separately, the overall performance of DMA/ethanol solution as a primer in dentin bonding was examined using micro-tensile bond strength (μTBS) testing, fracture pattern observation, and nanoleakage evaluation both immediately and after 10,000 times thermocycling aging. The inhibitory effect of DMA on endogenous metalloproteinases (MMPs) was evaluated by in situ zymography using confocal laser scanning microscopy (CLSM) and the cytotoxicity of DMA was evaluated using cell counting kit-8. Results demonstrated that DMA successfully cross-linked with dentin collagen via non-covalent bonds and had no influence on the polymerization and mechanical properties of the adhesive. Furthermore, even after 10,000 times thermocycling aging, the μTBS and nanoleakage expression of the DMA-treated groups showed no significant change compared with their immediate values. In situ zymography revealed reduced endogenous proteolytic activities after the application of DMA, and no cytotoxicity effect was observed for DMA concentration up to 25 μmol/L. Thus, DMA could be used as a novel, biocompatible functional monomer in dentin bonding.
The application of mussel-inspired molecule in dentin bonding Kang Li (Conceptualization) (Method... more The application of mussel-inspired molecule in dentin bonding Kang Li (Conceptualization) (Methodology) (Investigation) (Formal analysis) (Writing-original draft), Yuhong Sun (Investigation) (Formal analysis), James Kit Hon Tsoi (Supervision) (Writingreview and editing), Cynthia Kar Yung Yiu (Supervision) (Writingreview and editing) (Funding acquisition)
In this work, a low-cost, scalable and highly repeatable approach was developed to prepare polyst... more In this work, a low-cost, scalable and highly repeatable approach was developed to prepare polystyrene films with three-dimensional nanopyramids on the surface. The nanopyramids have a tunable aspect ratio and more importantly, their anti-bacterial performance has been systematically studied. The effectiveness of the nanopyramids on E. coli growth inhibition and the role of the nanostructure aspect ratio were carefully studied through scanning electron microscopy and confocal laser scanning microscopy. The results showed an excellent antibacterial performance with more than 90% reduction in the E. coli population in all nanopyramid samples after a 168 h prolonged incubation time. The nanopyramid film developed here can be used for clinical and commercial applications to prevent the growth of pathogenic bacteria on various surfaces. † Electronic supplementary information (ESI) available. See
Frontiers in Bioengineering and Biotechnology, Apr 27, 2021
Being as a non-pharmacological medical intervention, low-magnitude high-frequency vibration (LMHF... more Being as a non-pharmacological medical intervention, low-magnitude high-frequency vibration (LMHFV) has shown a positive effect on bone induction and remodeling for various muscle diseases in animal studies, among which dental implants osteointegration were reported to be improved as well. However, whether LMHFV can be clinically used in dental implant is still unknown. In this study, efficacy, parameters and side effects of LMHFV were analyzed via data before 15th July 2020, collecting from MEDLINE/PubMed, Embase, Ovid and Cochrane Library databases. In the screened 1,742 abstracts and 45 articles, 15 animal studies involving 972 implants were included. SYRCLE's tool was performed to assess the possible risk of bias for each study. The GRADE approach was applied to evaluate the quality of evidence. Random effects meta-analysis detected statistically significant in total BIC (P < 0.0001) and BV/TV (P = 0.001) upon loading LMHFV on implants. To conclude, LMHFV played an active role on BIC and BV/TV data according to the GRADE analysis results (medium and low quality of evidence). This might illustrate LMHFV to be a worthy way in improving osseointegration clinically, especially for osteoporosis. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO, identifier: NCT02612389
The aim of this study was to evaluate the effects of different etching time on the surface proper... more The aim of this study was to evaluate the effects of different etching time on the surface properties of dental porcelain used for veneer restoration. Totally, 32 rectangle porcelain specimens were prepared and randomly divided into four groups according to the corresponding etching protocols: control group (without any treatment), group A (etched with an acid gel for 30 s and rinsed), group B (etched for 1 min and rinsed), group C (etched for 2 min and rinsed). All the porcelain specimens were measured with values of surface roughness (Ra) and then subjected to the test of microhardness (Vickers Hardness). EDX technique was used to assess the changes in surface chemical composition after etching and the surface topography was recorded under atomic force microscope (AFM). It was found that the values of surface roughness of four groups were 0.11, 0.25, 0.50, and 0.52, respectively. The difference between group B and group C was not significant. The application of acid etching for 30 s decreased the Vickers hardness number significantly from 652 (control group) to 489 (group A). With the extension of etching time, the Vickers hardness number was further reduced to 430 (group B) and 306 (group C). AFM examination showed that longer etching time resulted in the formation of more surface voids and pits on porcelain surface. The results of EDX assessment indicated that group B had the highest silicon content which might be beneficial for the function of silane coupling agent. The application of surface acid etching reduced the microhardness number of dental porcelain. Acid etching on dental porcelain for 1 min tended to produce the most appropriate surface condition for bonding with resin cement.
The presence of Si on the Ti surface is quintessential for a strong, durable silane‐based adhesio... more The presence of Si on the Ti surface is quintessential for a strong, durable silane‐based adhesion utilized in several dental applications. Silica‐coating and silanization form durable ≡Si‐O‐Si≡ bonds, which might have a positive effect on resin‐Ti adhesion. This laboratory study studied the effect of strong acids, their blends, and silica‐coating on Ti and resin‐Ti bonding. One‐hundred sixty‐eight c.p. grade 2 polished Ti samples (10 mm × 10 mm × 1 mm), out of which 96 were etched with 9% and 12%HF, a blend of 35%HCl+85%H3PO4 and a blend of 69%HNO3+35%HCl at 60°C, each for 2 min. One half was silica‐coated (Rocatec™ Plus, 110 μm SiO2‐coated‐Al2O3). Sixty Ti samples were first silica‐coated, and then, 48 of them were etched with 9%HF, 12%HF, a blend of 35%HCl+85%H3PO4, and a blend of 69%HNO3+35%HCl at 60°C for 2 min. SEM, EDX, XPS, and Ra analyses were carried out. Polished Ti samples were controls. All silanizations were carried out with a blend of 0.3 vol% 1,2‐bis‐(triethoxysilyl)...
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The traditional metal-ceramic technique has been documented to be a reliable clinical application... more The traditional metal-ceramic technique has been documented to be a reliable clinical application. However, ceramic restorative materials have gained popularity in recent years. 1 These can be categorized into glass-matrix ceramics, polycrystalline ceramics, and resin-matrix ceramics. 2 Glass-matrix ceramics have an extensive history of application in dentistry as their chemical composition has a high amount of silica, making the material highly translucent, biomimetic, and biocompatible. 3 Advances in material properties have broadened the application of glass ceramics. The inherent brittleness and low fracture resistance of glass ceramics were improved either by incorporating reinforcing materials such as leucite or by the application of new materials, including lithium disilicate (LD). 3,4 With the launch of IPS Empress 2 in 1998 and IPS e.max Press in 2005, LD glass ceramics provided dentists with a ceramic with enhanced mechanical properties and natural appearance. With the flexural strength of over 300 MPa,
To evaluate the light transmission effects on the enclosed mold shear bond strength (EM-SBS) of r... more To evaluate the light transmission effects on the enclosed mold shear bond strength (EM-SBS) of resin-Ti covered with various hybrid CAD/CAM ceramics in different thickness. Materials and methods: Three CAD/CAM hybrid ceramics, Lava Ultimate TM , Cerasmart TM and Vita TM Enamic were cut into specimens with a size of 0.2 mm × 0.5 mm and thickness 0.2-1.0 mm. Ti sheets were cut, grit blasted and silanized with Monobond ® Plus. Polypropylene molds (2 mm in height) were used for resin stub preparation using Multilink ® Automix resin composite cement. An external mold was prepared to cover every sample and to make sure light only passes through ceramic. EM-SBS was measured using a universal testing machine. Results: Resin-Ti bonding cured under Lava Ultimate TM , showed higher EM-SBS than Cerasmart TM and Vita TM Enamic. The EM-SBS decreased with increasing thickness of each ceramic from 0.2 to1.0 mm. SEM, AFM and surface roughness profilometer showed surface roughness for Lava Ultimate TM , and Cerasmart TM was decreased after polishing and for Vita TM Enamic it was slightly increased. Conclusions: Resin-Ti bonding cured under Lava Ultimate TM , showed higher EM-SBS than Cerasmart TM and Vita TM Enamic. The EM-SBS decreased with increasing thickness of each ceramic from 0.2 to1.0 mm. SEM, AFM and surface roughness profilometer showed surface roughness for Lava Ultimate TM , and Cerasmart TM was decreased after polishing and for Vita TM Enamic it was slightly increased.
Background: The aim of the study was to investigate whether the citric acid and rough surface hav... more Background: The aim of the study was to investigate whether the citric acid and rough surface have a synergistic effect leading to severe wear behavior of resin composite. Materials and methods: Disk-shaped (Ø15 × 1.5 mm) specimens of resin composite (n = 12) with different initial roughness were prepared. Reciprocating ball-on-flat wear tests were performed under distilled water and citric acid (pH = 5.5) respectively. The coefficient of friction (COF), wear volume loss, and duration of the running-in period were quantified to assess the wear performance. And the values were analyzed with one-way ANOVA (α = 0.05). Regression analysis was applied to examine the influence of Ra values and mediums on the wear data. The wear morphology was analyzed by scanning electron microscopy and a 3D profilometer. Results: The average COF was higher in distilled water than in citric acid but was independent of the surface roughness. For the composite, the volume loss of worn area and running-in period increased with surface roughness when tested under distilled water. However, these increasing trends were not found in citric acid. All specimens exhibited mild wear behavior with low COF and less superficial abrasion in acidic medium. Conclusions: The effect of initial roughness on wear behavior depends on the medium. In distilled water, resin composites with high initial roughness exhibit a longer running-in time, which eventually leads to a significant increase in material loss. The adverse effects of high roughness can be alleviated by the lubrication of citric acid, which can maintain a mild wear behavior regardless of initial surface roughness.
Midpalatal suture was analysed with cone beam computed tomography to identify its maturation with... more Midpalatal suture was analysed with cone beam computed tomography to identify its maturation with respect to age and maxillary-complex growth in 72 patients 9-to 21-year-old. Maxillary-complex was divided in premaxillary, maxillary, and palatine segment. Interdigitation and ossification of midpalatal suture, its density relative to hard tissues and soft tissues, and midpalatal suture density ratio were measured for each segment. Correlation of each parameter with age and maxillarycomplex length was analysed, and classification trees were developed for staging parameters. Midpalatal suture maturation stages (MPSMS, from A to E) were applied to assess relationship with age and maxillary-complex length. Regarding age, ossification increased in maxillary segment of males (r S = 0.39, p = 0.032), while suture density relative to soft tissues increased in maxillary (r S = 0.37, p = 0.042) and palatine segments (r S = 0.41, p = 0.027) of males and in palatine segment of females (r S = 0.32, p = 0.041). In males, suture density relative to soft tissues discriminated two age-stages (p = 0.024), and the same parameter (p = 0.023) paired with ossification (p = 0.027) discriminated two length-stages. MPSMS identified length-differences between stage A and B in females (p = 0.001). Midpalatal-suture ossification and its density relative to soft tissues showed some relationship with age and maxillary-complex length, especially in males. However, challenging staging and limitations in the imaging method may limit clinical applications. Skeletal maturation refers to changes including shape modifications 1 , ossification of elements 2 , and density variations 3. Although longitudinal size measurements provide valid growth representations 1 , they have limited predictive value when applied to cross-sectional assessment of individuals 4. Thus, maturational assessments based on stages have been developed 1. Despite assessment of the overall skeletal maturational may be valid for facial growth as well 4 , maxillary growth differs from mandibular growth and may deserve a specific assessment 5 , with the midpalatal suture having been proposed as a suitable structure for such purpose 6. Differences in some midpalatal suture parameters have been reported from puberty to adulthood 7-9 , providing the rationale for a possible maturational assessment. A first parameter is the interdigitation i.e., the ratio between the suture length and the distance between its beginning and end 10 , exhibiting the change from a flat interface in infancy to an interdigitated structure in adolescence 7. A second one is the ossification i.e., the ratio between the ossified suture length and the suture length 9,10 , expressing the "fusion" that the suture begins during adolescence and that proceeds towards adulthood 9. A third one is the density ratio i.e., the ratio between the grey density of the suture and a reference area 11 , representing both the increase in bone mineral density that happens during skeletal maturation 3 and the sutural ligament ossification 9. This said, the maxillary-complex is
Numerous approaches have been developed to improve the resin-dentin bond performance, among which... more Numerous approaches have been developed to improve the resin-dentin bond performance, among which the bio-application of mussel-derived compounds have drawn great attention recently. To assess the performance of N-(3,4-dihydroxyphenethyl)methacrylamide (DMA), a mussel-derived compound, as a functional monomer in dental adhesive, its potential property to cross-link with dentin collagen and polymerize with adhesive will first be evaluated by transmission electron microscopy (TEM), attenuated total reflectance technique of Fourier transform infrared (ATR-FTIR), and atomic force microscopy (AFM) via Peakforce QNM mode. After validating the influence of DMA on collagen and adhesive separately, the overall performance of DMA/ethanol solution as a primer in dentin bonding was examined using micro-tensile bond strength (μTBS) testing, fracture pattern observation, and nanoleakage evaluation both immediately and after 10,000 times thermocycling aging. The inhibitory effect of DMA on endogenous metalloproteinases (MMPs) was evaluated by in situ zymography using confocal laser scanning microscopy (CLSM) and the cytotoxicity of DMA was evaluated using cell counting kit-8. Results demonstrated that DMA successfully cross-linked with dentin collagen via non-covalent bonds and had no influence on the polymerization and mechanical properties of the adhesive. Furthermore, even after 10,000 times thermocycling aging, the μTBS and nanoleakage expression of the DMA-treated groups showed no significant change compared with their immediate values. In situ zymography revealed reduced endogenous proteolytic activities after the application of DMA, and no cytotoxicity effect was observed for DMA concentration up to 25 μmol/L. Thus, DMA could be used as a novel, biocompatible functional monomer in dentin bonding.
The application of mussel-inspired molecule in dentin bonding Kang Li (Conceptualization) (Method... more The application of mussel-inspired molecule in dentin bonding Kang Li (Conceptualization) (Methodology) (Investigation) (Formal analysis) (Writing-original draft), Yuhong Sun (Investigation) (Formal analysis), James Kit Hon Tsoi (Supervision) (Writingreview and editing), Cynthia Kar Yung Yiu (Supervision) (Writingreview and editing) (Funding acquisition)
In this work, a low-cost, scalable and highly repeatable approach was developed to prepare polyst... more In this work, a low-cost, scalable and highly repeatable approach was developed to prepare polystyrene films with three-dimensional nanopyramids on the surface. The nanopyramids have a tunable aspect ratio and more importantly, their anti-bacterial performance has been systematically studied. The effectiveness of the nanopyramids on E. coli growth inhibition and the role of the nanostructure aspect ratio were carefully studied through scanning electron microscopy and confocal laser scanning microscopy. The results showed an excellent antibacterial performance with more than 90% reduction in the E. coli population in all nanopyramid samples after a 168 h prolonged incubation time. The nanopyramid film developed here can be used for clinical and commercial applications to prevent the growth of pathogenic bacteria on various surfaces. † Electronic supplementary information (ESI) available. See
Frontiers in Bioengineering and Biotechnology, Apr 27, 2021
Being as a non-pharmacological medical intervention, low-magnitude high-frequency vibration (LMHF... more Being as a non-pharmacological medical intervention, low-magnitude high-frequency vibration (LMHFV) has shown a positive effect on bone induction and remodeling for various muscle diseases in animal studies, among which dental implants osteointegration were reported to be improved as well. However, whether LMHFV can be clinically used in dental implant is still unknown. In this study, efficacy, parameters and side effects of LMHFV were analyzed via data before 15th July 2020, collecting from MEDLINE/PubMed, Embase, Ovid and Cochrane Library databases. In the screened 1,742 abstracts and 45 articles, 15 animal studies involving 972 implants were included. SYRCLE's tool was performed to assess the possible risk of bias for each study. The GRADE approach was applied to evaluate the quality of evidence. Random effects meta-analysis detected statistically significant in total BIC (P < 0.0001) and BV/TV (P = 0.001) upon loading LMHFV on implants. To conclude, LMHFV played an active role on BIC and BV/TV data according to the GRADE analysis results (medium and low quality of evidence). This might illustrate LMHFV to be a worthy way in improving osseointegration clinically, especially for osteoporosis. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO, identifier: NCT02612389
The aim of this study was to evaluate the effects of different etching time on the surface proper... more The aim of this study was to evaluate the effects of different etching time on the surface properties of dental porcelain used for veneer restoration. Totally, 32 rectangle porcelain specimens were prepared and randomly divided into four groups according to the corresponding etching protocols: control group (without any treatment), group A (etched with an acid gel for 30 s and rinsed), group B (etched for 1 min and rinsed), group C (etched for 2 min and rinsed). All the porcelain specimens were measured with values of surface roughness (Ra) and then subjected to the test of microhardness (Vickers Hardness). EDX technique was used to assess the changes in surface chemical composition after etching and the surface topography was recorded under atomic force microscope (AFM). It was found that the values of surface roughness of four groups were 0.11, 0.25, 0.50, and 0.52, respectively. The difference between group B and group C was not significant. The application of acid etching for 30 s decreased the Vickers hardness number significantly from 652 (control group) to 489 (group A). With the extension of etching time, the Vickers hardness number was further reduced to 430 (group B) and 306 (group C). AFM examination showed that longer etching time resulted in the formation of more surface voids and pits on porcelain surface. The results of EDX assessment indicated that group B had the highest silicon content which might be beneficial for the function of silane coupling agent. The application of surface acid etching reduced the microhardness number of dental porcelain. Acid etching on dental porcelain for 1 min tended to produce the most appropriate surface condition for bonding with resin cement.
The presence of Si on the Ti surface is quintessential for a strong, durable silane‐based adhesio... more The presence of Si on the Ti surface is quintessential for a strong, durable silane‐based adhesion utilized in several dental applications. Silica‐coating and silanization form durable ≡Si‐O‐Si≡ bonds, which might have a positive effect on resin‐Ti adhesion. This laboratory study studied the effect of strong acids, their blends, and silica‐coating on Ti and resin‐Ti bonding. One‐hundred sixty‐eight c.p. grade 2 polished Ti samples (10 mm × 10 mm × 1 mm), out of which 96 were etched with 9% and 12%HF, a blend of 35%HCl+85%H3PO4 and a blend of 69%HNO3+35%HCl at 60°C, each for 2 min. One half was silica‐coated (Rocatec™ Plus, 110 μm SiO2‐coated‐Al2O3). Sixty Ti samples were first silica‐coated, and then, 48 of them were etched with 9%HF, 12%HF, a blend of 35%HCl+85%H3PO4, and a blend of 69%HNO3+35%HCl at 60°C for 2 min. SEM, EDX, XPS, and Ra analyses were carried out. Polished Ti samples were controls. All silanizations were carried out with a blend of 0.3 vol% 1,2‐bis‐(triethoxysilyl)...
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