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Abstract The objective of this in vitro study is to examine the effect of antioxidants on the bonding strength of composite resin to bleached enamel. One hundred twenty non decay teeth were used in this study. Specimens were cut from the enamel cement junction. Then the specimens were randomly assigned into two groups-office bleaching and home bleaching. Bleaching antioxidants were applied to the first 12 subgroups. The specimens in the remaining 12 groups were kept in artificial saliva for 14 days and antioxidants were applied. Composite resin restoration was applied to all specimens. A cutting device was employed to obtain six specimens (0.9mm) from each tooth, and the microtensile bond strength (μTBS) test was performed. Data were analyzed using one-way ANOVA, the paired t-test, and Duncan's post hoc test (p=0.05). In office bleaching specimens, immediate antioxidant application increased the μTBS values (p0.05). Mean μTBS values in the groups to which antioxidants were applied two weeks after home bleaching were higher than those in the groups in which antioxidants were applied immediately. The use of antioxidants after bleaching may increase the MTBS value. The clinician should take this into account especially in immediate restoration applications after bleaching.
Resumen El objetivo de este estudio in vitro fue examinar el efecto de los antioxidantes sobre la resistência adhesiva de la resina compuesta al esmalte blanqueado. En este estudio se utilizaron ciento veinte dientes sin caries. Se cortaron especímenes a nivel de la unión esmalte-cemento. A continuación, los especímenes se asignaron aleatoriamente a dos grupos: blanqueamiento en el consultorio y blanqueamiento en casa. Se aplicaron antioxidantes de blanqueamiento a los primeros 12 subgrupos. Los especímenes de los 12 grupos restantes se mantuvieron en saliva artificial durante 14 días y se aplicaron antioxidantes. Se aplicó una resina compuesta a todos los especímenes empleando un dispositivo de corte para obtener seis especímenes (0,9mm) de cada diente, y se realizó la prueba de resistencia a la adhesión por microtensión (μTBS). Los datos se analizaron mediante un ANOVA de una vía, la prueba t pareada y la prueba post hoc de Duncan (p=0,05). En las muestras de blanqueamiento de oficina, la aplicación inmediata de antioxidantes aumentó los valores de μTBS (p0,05). Los valores medios de μTBS en los grupos a los que se aplicaron antioxidantes dos semanas después del blanqueo en casa fueron mayores que los de los grupos en los que se aplicaron antioxidantes inmediatamente. El uso de antioxidantes después del blanqueamiento puede aumentar el valor de μTBS. El clínico debe tenerlo en cuenta, especialmente en las aplicaciones de restauración inmediatas tras el blanqueamiento.
Subject(s)
Tooth Bleaching , Composite Resins/analysis , AntioxidantsABSTRACT
@#All-ceramic restorations are widely used in oral restoration because of their beauty and high strength. Glass ceramics and zirconia all-ceramic materials are the two most widely used all-ceramic materials in the clinic. However, when all-ceramic restorations need to be removed due to marginal microleakage and secondary caries, its high strength and high bonding strength greatly increase the difficulty of removal. In recent years, clinicians have tried to use Er: YAG lasers to remove all-ceramic restorations. The Er: YAG laser can be safely and efficiently applied to the removal of glass restorations, and it can also play a role in thinner zirconia restorations. Various factors, such as the material and thickness of the all-ceramic restoration, the type of cement, and the laser power, can affect the speed of removal of the Er: YAG laser. However, the current research is limited to case reports and in vitro studies, lacking systematic clinical research. The specific mechanism of Er: YAG laser removal of all-ceramic restorations and the influence of laser frequency, adhesive type, and abutment on the removal speed need to be further demonstrated by follow-up research.
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Objective@# To observe the effect of dopamine pretreatment of the root canal on improving the bonding performance of AH-plus sealer.@*Methods @# A total of 32 freshly isolated permanent teeth with a single canal were collected, with no caries, no fracture of roots, and a root canal curvature<10°. All sample root canals were prepared to F2 with ProTaper rotating nickel-titanium instruments and then treated with 1 mg/mL, 2 mg/mL, or 3 mg/mL dopamine solution for 24 hours and divided into 4 groups (n = 8): 0 mg/mL dopamine group (blank control group), 1 mg/mL dopamine group, 2 mg/mL dopamine group, and 3 mg/mL dopamine group. Scanning electron microscopy was used to observe the combination of dopamine and root canal dentin wall; laser confocal scanning microscopy was used to observe the penetration of AH-plus sealer; and root canal filling was performed with AH-plus sealer and gutta-percha tip using the cold gutta-percha lateral pressure technique. The root canal samples were cut horizontally at the middle and the apical third sections of the root with a slice thickness of 1-2 mm. The push-out test was carried out under an Instron universal testing machine to compare the push-out bonding strength between each group. @*Results @#Scanning electron microscopy showed that most of the dentinal tubules were open in the control group after 0 mg/mL dopamine solution treatment for 24 hours. In the 1 mg/mL group, a small number of dopamine particles on the surface of the dentin tubules in the inner wall of the root canal were loose and unevenly distributed. In the 2 mg/mL group, most of the dentinal tubules were covered by dopamine particles, and the dopamine layer was uniform and dense. In the 3 mg/mL group, a large number of dopamine particles were deposited at the mouth of the dentinal tubules, but the distribution was uneven. Dopamine and AH-plus sealer can be seen to simultaneously infiltrate into dentinal tubules under a confocal laser scanning microscope. The interaction of the two factors, the anatomical location and dopamine concentration, had no significant effects on the bonding strength of AH-plus sealer (P>0.05). Root canals treated with 2 mg/mL dopamine had the highest bonding strength in all groups (P<0.05). Analysis of the push-out test of bonding strength with AH-plus sealer at different anatomical locations showed significant differences (P<0.05). The push-out bonding strength of the AH-plus sealer in the middle third section of the root was higher than that in the apical third section of the root.@*Conclusion@# Different dopamine concentrations could affect the bonding strength of AH-plus sealer in root canals. When treated with 2 mg/mL dopamine for 24 hours, the bonding effect of AH-plus sealer in root canals was improved.
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BACKGROUND: Due to the stability of the physical and chemical properties of zirconia ceramics, its poor adhesiveness has seriously affected the clinical application of zirconia ceramic prosthesis. OBJECTIVE: To analyze the effect of different surface treatment methods and resin cement on the bonding strength of zirconia ceramics. METHODS: Totally 240 zirconia blocks were randomly divided into 16 groups, with 15 in each group. In group A, the treatment method was sandblasting+hydrofluoric acid+Monobond-s+Panavia F 2.0. In group B, the treatment method was sandblasting+hydrofluoric acid+Monobond-s+Perma CemDual. In group C, the treatment method was sandblasting+hydrofluoric acid+new silane coupling agent+Panavia F 2.0. In group D, the treatment method was sandblasting+hydrofluoric acid+new silane coupling agent+Perma Cem-Dual. In group E, the treatment method was sandblasting+Monobond-s+Panavia F 2.0. In group F, the treatment method was sandblasting+Monobond-s+Perma Cem-Dual. In group G, the treatment method was sandblasting+Monobond-s+Panavia F 2.0 resin cement binder. In group H, the treatment method was sandblasting+new silane coupling agent+Perma Cem-Dual. In group I, the treatment method was hydrofluoric acid+Monobond-s+Panavia F 2.0. In group J, the treatment method was hydrofluoric acid+Monobond-s+Perma Cem-Dual. In group K, the treatment method was hydrofluoric acid+new silane coupling agent+Panavia F 2.0. In group L, the treatment method was hydrofluoric acid+new silane coupling agent+Perma Cem-Dual. In group M, the treatment method was Monobond-s+Panavia F 2.0. In group N, the treatment method was Monobond-s+Perma CemDual. In group O, the treatment method was new silane coupling agent+Panavia F 2.0. In group P, the treatment method was new silane coupling agent+Perma Cem-Dual. Panavia F 2.0 and Perma Cem-Dual were resin cement binders. Monobond-s was commercial silane coupling agent. The bonding strength of each group was tested. RESULTS AND CONCLUSION: (1) The bonding strength of groups C, G and H was higher than that of the remaining 13 groups (P < 0.05). The bonding strength of groups A, B, C, D, E, F, G and H was higher than that of groups I, J, K, L, M, N, and P (P < 0.05). (2) The results show that the combined use of zirconia sandblasting and new silane coupling agent can significantly improve the bonding strength of ceramic-cement. Hydrofluoric acid pretreatment is ineffective. The different types of cement will have a certain effect on the bonding strength.
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@#Hydrofluoric acid is a common surface treatment agent for glass ceramic restorations before bonding. However, the use of hydrofluoric acid has a high safety risk, so the search for hydrofluoric acid substitutes has been a research hotspot. Tetrabutylammonium dihydrogen trifluoride is a kind of fluoride, whose chemical activity is lower than that of hydrofluoric acid, so it’s safer, and the surface morphology changes on glass ceramics caused by it are smaller and more superficial. At present, the vast majority of laboratory studies and clinical case reports indicate that the mechanical strength and bonding strength of glass ceramics treated with tetrabutylammonium dihydrogen trifluoride can meet the clinical requirements. In the future, according to the research results, the performance of porcelain surface treatment agents containing tetrabutylammonium dihydrogen trifluoride can be further improved, and more hydrofluoric acid substitutes may be developed. In this review, the research progress of tetrabutylammonium dihydrogen trifluoride as a substitute for hydrofluoric acid is reviewed in terms of the influence of the surface morphology, mechanical strength, and bonding strength of glass ceramics.
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Objective @#To explore the effects of two hemostatic agents on the bonding strength of different bonding systems in primary tooth dentin.@*Methods @# Seventy-two retained deciduous teeth were randomly selected. Forty-eight teeth were used to construct the microleakage model, the other 24 teeth were cut along the mesial and distal directions and 48 samples were obtained to construct the shear bond strength model. The two experiments were divided into 2 groups. Group A was the total-etch group: A1 (ViscoStat + Spectrum Bond NT); A2 (ViscoStat Clear + Spectrum Bond NT); and A3 (Non + Spectrum Bond NT); Group B was the self-etch group: B1 (ViscoStat + Single bond Universal Adhesive); B2 (ViscoStat Clear + Single bond Universal Adhesive); and B3 (Non + Single bond Universal Adhesive). Microleakage experiments and shear bond strength experiments were carried out respectively and the morphology of the fracture surface was observed by scanning electron microscopy.@* Results @#There was no significant difference in microleakage among groups A1, A2, and A3 (P > 0.05). There was no significant difference in microleakage among groups B1, B2, and B3 (P > 0.05). There was no significant difference in the shear bond strength among groups A1, A2 and A3 (P > 0.05). The shear bond strength of groups B1 and B2 was significantly lower than that of group B3 (P < 0.05). There was no significant difference between groups B1 and B2 (P > 0.05). @*Conclusion@#ViscoStat and ViscoStat Clear had no effect on the marginal integrity of deciduous tooth dentin under the different bonding systems. The two hemostatic agents reduced the shear bonding strength of deciduous tooth dentin under the self-etch adhesive system, but had no effect on the shear bonding strength of deciduous tooth dentin under the total-etch adhesive system.
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Objective @# To evaluate the effect of different surface treatments on the bonding strength between highly translucent zirconia and veneering porcelain and to provide a research basis for improving the zirconium porcelain bond strength between zirconium and ceramic material.@*Methods @# Thirty cylindrical zirconia blocks with 10-mm diameter and 10-mm height were prepared and divided into four groups (n=7), labeled as control group (C), sandblasting group (S), bonding group (B), and sandblasting and bonding group (SB). The surface morphology of zirconia before and after sandblasting was observed in the remaining two specimens. Group C was veneered (2 mm in height and 5 mm in diameter) with porcelain powder by layering after grinding. Group S was sandblasted after grinding. Group B was veneered with a thin layer of porcelain powder as bond coating. Group SB was sandblasted and veneered with a thin layer of porcelain powder. After sintering, the shear specimens were embedded, and a shear bond strength test was conducted. Statistical analysis was conducted to analyze the data. Fracture surface analysis was also performed to determine the failure modes by stereomicroscopy.@*Results @# The bonding strength of group C was 21.86 ± 3.18 MPa. For group S, it was 22.12 ± 3.06 MPa. For group B, it was 19.19 ± 1.46 MPa. Finally, for group SB, it was 27.76 ± 1.95 MPa. There was no significant difference in shear strength between group C, group S and group B. There was a significant difference in shear strength between each group and group SB (P < 0.05). Under a stereomicroscope, the observed fracture modes of each group were mainly mixed failure.@*Conclusion@#Sandblasting cannot significantly increase the bonding strength between zirconia and veneering porcelain. Veneering with a thin layer of porcelain powder as the bond coating has no obvious effect on the bonding strength. Sandblasting and veneering with a thin layer of porcelain powder as a bond coating can significantly improve the bonding strength between zirconia and veneering porcelain.
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@#Er: YAG laser bleaching is a new tooth bleaching method compared with traditional bleaching technology. The Er: YAG laser significantly improves the bleaching efficiency, has the advantages of high safety, short treatment time and excellent bleaching effect and is widely used in clinical operations. This paper summarizes the working principle and bleaching characteristics of Er: YAG laser bleaching technology and its effect on tooth structure. The existing literature suggests that the high absorption of water and hydroxyapatite by the Er: YAG laser makes it work well on water-bearing tissues and dental tissues. When it is absorbed by the bleaching agent on the tooth surface, it accelerates the catalytic oxidation-reduction reaction and selectively acts on the pigment particles deposited on the tooth, thereby achieving the effect of tooth bleaching. Er: YAG laser bleaching can be applied to most discolored teeth. The bleaching process is rapid and effective. During the bleaching process, for the dental pulp tissue, the temperature of the pulp cavity is lower than the critical value of 5.6 ℃, causing no pathological damage to the dental pulp tissue. For the hard tissues of the teeth, laser irradiation will cause changes in the chemical composition of calcium and phosphorus. The enamel presents a unique lava-like shape, and the bonding strength of the tooth increases after bleaching. Compared with other lasers, the Er: YAG laser has a wavelength close to the peak of water, and adding other ingredients to the bleaching agent is not required. Almost all the energy is used for the bleaching agent, with no damage to the surrounding tissues.
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Accurate diagnosis and proper treatment planning should be established before making any prosthetic rehabilitation to restore the good appearance of the tooth, a better smile, phonetics, and to achieve perfect occlusion/mastication. We wanted to evaluate the changes of surface treatment protocols on the tensile bonding strength between enamel and ceramic restorations (lithium disilicate).METHODSA total of 20 freshly extracted, non-carious teeth were stored in normal saline solution at 25°C until used. Clean enamel surfaces 2 mm X 2 mm were obtained from the extracted teeth by using wheel diamond bur. Each enamel side received one E-max sprue, so four sprues of different surface treatment protocols per tooth (G1 TS: Etching, bonding, and curing. CS: Etching, monobond, curing, overall light cure) (G2 TS: Bonding, curing, self-etch / self-adhesive resin cement, overall light cure. CS: Monobond etch and prime) (G3 TS: Etching, bonding without curing. CS: Etching, monobond, curing, overall light cure) (G4 TS: Etching, bonding, curing. CS: Etching, monobond, bonding, curing, light-cure resin cement, overall light cure). Tensile bonding strength was measured using the Instron testing machine. One-way ANOVA test was used to analyse the data.RESULTSThe highest mean was observed in Group 3 (124.34±43.47) followed by Group 1 (104.29±50.09), which is control group. In contrast, the lowest mean was observed in Group 2 (83.64 ± 53.56) and Group 4 (94.14±57.91). The results of ANOVA test have shown a significant difference between the surface treatment groups at 5% significance level.CONCLUSIONSHydrofluoric acid and primer/silane coupling agent create a porous surface on the ceramic that allow a good interaction with silane coupling agent.
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Background@#Hydrogen bonding interaction was considered to play a critical role in controlling drug release from transdermal patch. However, the quantitative evaluation of hydrogen bonding strength between drug and polar functional group was rarely reported, and the relationship between hydrogen bonding strength and controlled release capacity of pressure sensitive adhesive (PSA) was not well understood. The present study shed light on this relationship.@*Methods@#Acrylate PSAs with amide group were synthesized by a free radical-initiated solution polymerization. Six drugs, , etodolac, ketoprofen, gemfibrozil, zolmitriptan, propranolol and lidocaine, were selected as model drugs. drug release and skin permeation experiments and pharmacokinetic experiment were performed. Partial correlation analysis, fourier-transform infrared spectroscopy and molecular simulation were conducted to provide molecular details of drug-PSA interactions. Mechanical test, rheology study, and modulated differential scanning calorimetry study were performed to scrutinize the free volume and molecular mobility of PSAs.@*Results@#Release rate of all six drugs from amide PSAs decreased with the increase of amide group concentrations; however, only zolmitriptan and propranolol showed decreased skin permeation rate. It was found that drug release was controlled by amide group through hydrogen bonding, and controlled release extent was positively correlated with hydrogen bonding strength.@*Conclusion@#From these results, we concluded that drugs with strong hydrogen bond forming ability and high skin permeation were suitable to use amide PSAs to regulate their release rate from patch.
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@#The concept of “minimally invasive dentistry” aims to provide conservative treatment of cavities in which sound dentin is removed. Because the Er: YAG laser can selectively remove caries, the smear layer is removed, dentin tubules are exposed after the preparation of substrate conditioning, and its advantages of precision, safety and painlessness are deeply valued. At the same time, the bonding strength between the prepared dentin surface and the filling material is different due to the different parameters of the Er: YAG laser. In this paper, the principle of dentin bonding, the mechanism of Er: YAG laser action, after treatment of dentin with different parameters (power, energy density, pulse duration, and irradiation distance), whether there is thermal damage to pulp tissue, the ultramicro morphology of dentin surface, the bonding properties of different bonding systems and the filling materials between irradiated hard tissues were reviewed. An appropriate parameter range (power ≤ 10 Hz, energy density ≤ 60 mJ, and pulse duration ≤ 50 μs) combined with water spray cooling will not cause thermal damage to the pulp tissue, while the higher power, energy density and pulse duration of laser treatment for dentin will lead to melting, carbonization, cracks, narrowing of the gap between collagen fibers, etc., which will limit the penetration of adhesives and have a negative impact on bonding. However, whether the adhesive systems based on the smear layer are suitable for dentin after laser treatment needs to be further explored.
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Objective: To optimize the formulation of Jieyu Anshen Gel Plaster (JAGP) and evaluate its quality. Methods: With the bonding strength and sensory evaluation scores as indicators, the formulation of JAGP was optimized by using orthogonal experiment design method. Then the content of methyl eugenol, elemicin, β-asarone and α-asarone in JAGP were determined by GC-MS and the in vitro transdermal properties were studied by modified Franz diffusion cells. Results: The optimized blank matrix formulation was as following: NP700 of 3%, glycerol of 36%, PVP K30 of 4% and aluminium glycinate of 0.08%. The containing ointment of prepared gel plaster was 217.4 mg/cm2 and the effective component of the total index in gel paste was 5.77 mg/paste. Then the accumulated transdermal permeation of methyl eugenol, elemicin, β-asarone and α-asarone was (81.798 6 ± 14.872 6), (72.110 2 ± 17.776 1), (146.390 6 ± 33.794 1), (5.522 6 ± 1.279 6) μg/cm2, respectively within 24 h, which were all consistent with the zero-order equation. Conclusion: The preparation of JAGP with good stability and drug-releasing properties conformed to the relevant quality requirement, And this study provides certain basis for the development of production.
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BACKGROUND: At present, there is no uniform standard for the treatment time of chemical reagents for surface treatment of glass fiber posts. Therefore, studying the effect of treatment time of glass fiber post surface treatment reagents on the bond strength between fiber posts and resin cements is of great significance. OBJECTIVE: To evaluate the effect of two chemical agents on the bonding strength of glass fiber post and resin cement after surface pretreatment of glass-fiber posts at different times. METHODS: Forty-eight glass fiber posts were randomly divided into eight groups according to different surface treatment methods, six in each group. Group A received no special treatment; group B was treated with silanization for 1 minute; group C1 underwent a 30% hydrogen peroxide surface treatment for 5 minutes prior to 1-minute silanization; group C2underwent a 30% hydrogen peroxide surface treatment for 10minutes prior to 1-minutesilanization; group C3 underwent a 30% hydrogen peroxide surface treatment for 15 minutes prior to 1-minute silanization; group D1 underwent a 35% phosphoric acid surface treatment for 30 seconds prior to 1-minute silanization; group D2 underwent a 35% phosphoric acid surface treatment for 60 seconds prior to 1-minute silanization; group D3 underwent a 35% phosphoric acid surface treatment for 90 seconds prior to 1-minute silanization. The surface morphology of the treated glass fiber posts was observed under scanning electron microscope. The glass fiber post was bonded to the resin cement to form a cylindrical resin block and cut into a thin sample. The sheet was placed on a universal testing machine for micro-extrusion experiments. The failure mode of the specimens was observed under a stereomicroscope. RESULTS AND CONCLUSION: (1) Scanning electron microscope: the surface of the fiber post had different degrees of matrix dissolution and fiber bundle exposure after hydrogen peroxide and phosphoric acid treatment, but did not destroy the integrity of the fiber bundle. (2) Micro-extrusion experiments: the order of the bonding strength was as follows: group C3 > group C2 > group C1 > group D2 > groupD3 > groupD1> group B > group A, and there was significant difference between groups (P< 0.05) except for groups A and B, groups C2 andC3, and groups D2and D3. (3) Stereo microscope: the failure mode in the groups A and B was almost destruction in adhesion. The other six groups showed destruction in adhesion, but the cohesive failure and mixed failure were increased, and the failure mode changed from destruction in adhesion into cohesive failure and mixed failure. (4) These results indicate that the optimal treatment time of 30% hydrogen peroxide is 10 minutes, and the optimal treatment time of 35% phosphoric acid is 60 seconds. 30% hydrogen peroxide solution treatment of fiber post surface for 10 minutes has great clinical application value.
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Objective@#To explore the best indication for veneers and to improve the repair success rate by investigating the effects of different types of dentin exposure on the shear bond strength of cast porcelain veneers with two new veneer bonding systems.@*Methods@#Bonding interfaces with 0%, 25%, 50%, 75% and 100% dentin exposure were designed and fabricated. The bonding interfaces were divided into groups A, B, C, D and E. Sixty 4-mm x 4-mm x 2-mm (length x width x thickness) ceramic specimens were bonded by using two bonding systems, The VN-A, VN-B, VN-C, VN-D and VN-E groups were bonded with Variolink bonding system, and the PF-A, PF-B, PF-C, PF-D and PF-E were bonded with Panavia F bonding system (six specimens per group). The bonded specimens were stored in a distilled water bath at (37 + 1)℃ for 24 hours. The fracture load was tested by a universal testing machine, and the fracture type was observed by scanning electron microscopy.@*Results @#The VN-A (25.14 ± 3.40 MPa), VN-B (22.54 ± 4.48 MPa), VN-C (19.59 ± 2.21 MPa), PF-A (20.61 ± 2.42 MPa), PF-B (18.08 ± 4.11 MPa), PF-C (17.06 ± 2.29 MPa) groups’ shear bond strengths were above 17 MPa. The VN-A group had the highest shear bond strength value. There was no statistically significant difference in bond strength between the VN-A group and the VN-B and VN-C groups (P > 0.05) or the PF-A and PF-B groups (P > 0.05); however, the differences between VN-A and the VN-D and VN-E groups (P < 0.05) and between PF-A and the PF-C and PF-D and PF-E groups (P < 0.05) were statistically significant. The differences between the VN-A group and PF-A group (P < 0.05) were statistically significant. The fracture modes of the VN-A, PF-A, VN-B, PF-B, and VN-C groups mainly included resin cement cohesive failure and mixed failure; the VN-D, VN-E, PF-C, PF-D and PF-E groups were dominated by interface failure and mixed failure.@*Conclusion@#When the dentin exposure is greater than 50%, the shear bond strength value of the veneer was significantly affected. To obtain a better clinical effect, the dentin exposure rate should be less than 25%.
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@#When the root canal is filled, the use of the adhesive resin-based sealant to form a strong bond with the dentin reduces microleakage of the apex, enhances the bending resistance of the tooth, and resists the mechanical damage of the pile preparation, thus improving the success rate of root canal treatment. However, during root canal treatment, the use of a rinsing agent may change the tissue structure of the dentin and the wettability of the dentin, thereby affecting the bonding strength between the resin sealing agent and the dentin. In this paper, the effects of a traditional root canal irrigant and several new rinsing agents on the bonding strength of resin sealant and dentin are reviewed. The results show that the traditional root canal rinsing agent NaClO is reduced as the final rinsing agent. The bonding strength of resin sealant to dentin; EDTA affects the biomechanical properties of root dentin, and the removal efficiency is low, which will affect the bond strength between the resin sealant and dentin. EDTA combined with NaClO as a final rinsing agent can improve the bonding strength. Chlorhexidine can also increase the bonding strength between the blocking agent and dentin and can be used as the final rinsing agent. The new rinsing agent MTAD has a negative impact on the resin sealing agent and dentin bond strength. QMix and maleic acid remove smear efficiency with dentin bond strengths greater than or equal to EDTA and can replace EDTA as the final rinse.
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Objective @#To investigate different Er:YAG laser power settings on the bonding properties of IPS e.max CAD ceramics. @*Methods@# 96 IPS e.max CAD ceramics blocks (5 mm × 5 mm × 5 mm) were prepared and randomly divided into 8 groups (n = 12), the untreated blocks served as the control, while one of the experimental groups was treated with 4.5% HF for 20 seconds, six remaining test group (C、D、E、F、G、H) were treated with different Er: YAG laser power settings: 100 mJ、200 mJ、300 mJ、400 mJ、500 mJ and 600 mJ. Morphology of the ceramic surface was observed by atomic force microscopy and its shear bond strength (SBS) was tested. @*Results @#Higher shear bond strength values were found in group C-H compared to group B, the highest is group F (24.12 ± 1.91) MPa. The difference was statistically significant. The atomic force microscope observation of the surface structure showed that the control group was smooth and flat, and the HF-like etching group formed a uniform needle-like convex structure. The laser group gradually formed a regularly arranged cylindrical convex structure, in which the surface of the G and H groups was damaged. @*Conclusion @#The Er: YAG laser power settings of 400 mJ can be used as an effective pretreatment method before bonding of IPS e.max CAD ceramic.
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OBJECTIVE@#To compare the dentin bonding strength evaluation between adult permanent teeth and youth permanent teeth after treatment for different durations by universal adhesives.@*METHODS@#Ten adult permanent teeth and ten youth permanent teeth were selected for this study. The occlusal enamel layer was removed, and each tooth was cut into three pieces along the long axis. In total, 30 pieces of adult and youth teeth were prepared. The adult and youth teeth pieces were randomly divided into three groups and treated by universal adhesives for 10, 20, and 30 s. In this study, Scotchbond Universal (SBU) was selected as the universal adhesive. Slabs were treated by dual-cure resin cements. The specimens were tested by microshear strength test through a universal testing machine. Fracture modes were observed by a stereomicroscope. Other adult teeth and youth teeth were selected, two for each type, and treated and grouped in the same manner. Fluorescein (0.1% Rhodamine B) was dissolved in SBU adhesive, and the specimens were treated by the adhesives for 10, 20, and 30 s. Micromorphology of the resin protrusions on the adhesive surface was observed by laser confocal microscopy (CLSM).@*RESULTS@#For the adult teeth, the highest micro-shear bonding strength was observed in the 20 and 30 s groups, and the values were higher than that of the 10 s group (P0.05). The main break patterns in different groups comprised adhesive failure fractures and several mixed failure fractures. No resin fracture mode was observed. CLSM revealed very few short resin protrusions in 10 s adult teeth group, whereas the number and length of resin protrusions significantly increased in the 20 s adult teeth group. The resin protrusions of the 30 s group were shorter than those of the 20 s adult teeth group. In different durations, the bonding interface in different youth teeth groups presented the same trend of change as the adult teeth. However, the number and length of resin protrusions in the 10 s group of youth teeth were all higher than those of the 10 s adult teeth group.@*CONCLUSIONS@#In clinical practice, the bonding agent treatment duration shall be shortened appropriately for youth permanent teeth, and that for adult permanent teeth shall not be shortened to less than 20 s. On the whole, the bond strength of youth permanent teeth can achieve no significant difference with the adult permanent teeth.
Subject(s)
Adult , Humans , Acid Etching, Dental , Composite Resins , Dental Bonding , Dental Cements , Dental Stress Analysis , Dentin , Dentin-Bonding Agents , Materials Testing , Random Allocation , Resin CementsABSTRACT
OBJECTIVE@#To investigate the effect of different sandblasting conditions on the metal-ceramic bonding strength of Co-Cr alloy fabricated by selective laser melting (SLM) technology.@*METHODS@#A total of 63 specimens of Co-Cr alloy fabricated by SLM were prepared and randomly divided into nine groups (n=7). Each group was treated with different powder particles (A1=50 µm, A2=100 µm, and A3=150 µm) and pressures (B1=0.2 MPa, B2=0.4 MPa, and B3=0.6 MPa) in sandblasting. One sample was randomly selected from each group for microstructure observation by scanning electron microscope (SEM). Ceramic was fired at the center of the specimens. Metal-ceramic bonding strength was measured with universal testing machine. Results were statistically analyzed with SPSS 17.0 software.@*RESULTS@#The mean bond strengths were as follows: Group A1B1: 27.22 MPa±0.95 MPa, Group A1B2: 27.58 MPa±0.47 MPa, Group A1B3: 26.80 MPa±0.71 MPa, Group A2B1: 27.54 MPa±0.78 MPa, Group A2B2: 30.75 MPa±0.43 MPa, Group A2B3: 26.93 MPa±0.88 MPa, Group A3B1: 28.18 MPa±0.93 MPa, Group A3B2: 29.55 MPa±0.57 MPa, and Group A3B3: 28.11 MPa±0.91 MPa. The particle factor of Al₂O₃ and the pressure factor of blasting showed statistical significance (P<0.05). An interaction was observed between the factors of particle and pressure (P<0.05). Mixed fracture mode of all specimens was observed after the shear strength test.@*CONCLUSIONS@#In conclusion, metal-ceramic bonding strength reaches the maximum when specimens are sandblasted with 100 µm alumina oxide at 0.4 MPa pressure.
Subject(s)
Ceramics , Dental Bonding , Materials Testing , Microscopy, Electron, Scanning , Shear Strength , Surface PropertiesABSTRACT
Objective@#To investigate different Er:YAG laser power settings on the bonding properties of IPS e.max CAD ceramics. @*Methods @# 96 IPS e.max CAD ceramics blocks (5 mm × 5 mm × 5 mm) were prepared and randomly divided into 8 groups (n = 12), the untreated blocks served as the control, while one of the experimental groups was treated with 4.5% HF for 20 seconds, six remaining test group (C、D、E、F、G、H) were treated with different Er: YAG laser power settings: 100 mJ、200 mJ、300 mJ、400 mJ、500 mJ and 600 mJ. Morphology of the ceramic surface was observed by atomic force microscopy and its shear bond strength (SBS) was tested. @*Results @#Higher shear bond strength values were found in group C-H compared to group B, the highest is group F (24.12 ± 1.91) MPa. The difference was statistically significant. The atomic force microscope observation of the surface structure showed that the control group was smooth and flat, and the HF-like etching group formed a uniform needle-like convex structure. The laser group gradually formed a regularly arranged cylindrical convex structure, in which the surface of the G and H groups was damaged. @*Conclusion@# The Er: YAG laser power settings of 400 mJ can be used as an effective pretreatment method before bonding of IPS e.max CAD ceramic.
ABSTRACT
Objective To observe the effect of UltraEZTM desensitization on dentin bonding strength and microstructure.Methods In vitro studies were performed with 90 third molars,which randomly divided into group A,group B and control group,with 30 particles in each group.Group A was treated with UltraEZTM for desensitization,group B was desensitized with MI paste,and Group C was not desensitized.Than the three groups were divided into two subgroups,each of 15 particles.Two subgroups were coated with full acid etching adhesive and self-etching adhesive.The bonding strength of dentin and enamel after bonding with three self-etching adhesives,the fracture patterns of the three groups were compared.The microstructures of the interface were observed by scanning electron microscopy.Results The dentin bonding strength and enamel adhesion strength by full acid etching adhesive and self-etching adhesive in group A were were higher than those in group B (P ＜ 0.05),and comparable to the control group (P ＞ 0.05).The fracture pattern of the total etching adhesive and self-etching adhesive in the control group were mainly C type (66.67％,73.33％),partly B type (33.33％,26.67％).In Group A,there were mainly C type (46.67％,53.33％),partly A-type and B-type fracture.In B group,there were with B-type fracture (60.00％,73.33％) mainly,part of A-type C-type fracture.The distribution of fracture pattern in the three groups was statistically significant (P ＜ 0.05).Conclusion The application of UltraEZTM desensitizer did not significantly affect dentin bonding strength,and the microscopic morphology was close to that of untreated dentin,which was the first choice for desensitization.