Influence of the dentin smear layer trait on the bond strength of the self-adhesive resin cements / 华西口腔医学杂志

OBJECTIVE@#This work aimed to evaluate the influence of smear layer on the bonding effectiveness and durability of the self-adhesive resin cements to dentin.@*METHODS@#A total of 48 fresh caries-free third molars with exposed dentin surface were divided into two groups. The dentin surfaces were treated using a standard grit diamond bur (group A) or further polished using a fine grit diamond bur (group B) and then bonded with either of the two self-adhesive resin cements, namely, Clearfil SA Cement (CSA, Kuraray) and Multilink Speed (MS, Ivoclar Vivadent). After 24 h or 2-year water storage, a microtensile bond strength test was performed.@*RESULTS@#In group A, the dentin surface was rough, the smear layer was thick, and the dentin tubule orifice detritus showed low embolism value. In group B, the dentin surface roughness decreased, the embolism proportion increased, and the smear layer became thin. The initial bonding strengths of CSA and MS in group A were significantly lower than those in group B (P0.05).@*CONCLUSIONS@#The properties of the smear layer and the types of self-adhesive resin cement used affected the bond strength and durability.

Effect of curing modes on knoop hardness and microtensile bond strength of two dentin adhesives / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluated the effect of curing modes and light-cure times on knoop hardness (KH) and microtensile bond strength (µTBS) of dentin adhesives in vitro.</p><p><b>METHODS</b>Twenty molars were made into 80 dentin slices (about 1 mm thick). The dentin slices were prepared with an etch&rinse adhesive A (ONE-STEP PLUS) and a self-etch adhesive B (Clearfil SE Bond), and light-cured respectively under fast mode, i.e.1250 mW/cm(2) light intensity for 10 s, 15 s, 20 s, and ramp mode (soft start curing mode), i.e.initial 0 mW/cm(2) gradually increasing to 1250 mW/cm(2) in first 10 s, then steady for the next 10 s. The prepared dentin slices were kept in dark dry room for 24 h at 37°C, and KH were tested. The other 40 molars were flattened to expose coronal dentin, prepared with adhesives as above. Then the prepared teeth were restored with resin composites incrementally and cured under fast mode. The restored teeth were stored in water for 24 h at 37°C, and slowly sectioned to obtain multiple bonded beams. After 7 d water-storage, the samples received microtensile bond test, and the failure models of beams were observed under a stereomicroscope. Data were analyzed by ANOVA and LSD test (α = 0.05).</p><p><b>RESULTS</b>No statistical difference in KH [(28.20 ± 5.36), (29.13 ± 5.60), (28.13 ± 4.40), (27.06 ± 3.77) MPa] and µTBS [(22.30 ± 5.07), (22.73 ± 6.59), (26.32 ± 6.17), (25.67 ± 4.31) MPa] of adhesive A were found between four curing conditions (fast mode for 10 s, 15 s, 20 s and ramp mode for 20 s) (P > 0.05). In adhesive B, KH of Fast 20 s [(28.23 ± 3.67) MPa] were significantly higher than those of Fast 10 s [(14.15 ± 2.24) MPa] and Fast 15 s [(17.63 ± 2.17) MPa] (P < 0.05). The µTBS of Fast 20 s [(42.52 ± 3.59) MPa] were significantly higher than those of Fast 10 s [(24.21 ± 3.60) MPa], Fast 15 s [(22.25 ± 4.16) MPa] and Ramp 20 s [(31.12 ± 5.40) MPa] (P < 0.05). In Fast 20 s and Ramp 20 s modes, there were no statistical difference in KH of adhesive A and B, while µTBS of adhesive B were higher than that of adhesive A(P < 0.05).</p><p><b>CONCLUSIONS</b>As for different type dentin adhesives, the appropriate curing time in fast mode is different, and ramp mode (soft start curing mode) has no advantage over fast mode.</p>

Effects of sandblasting on surface character and resin bond of zirconia ceramic / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of Al2O3 particles sandblasting on the surface roughness, element composition and resin bond durability of zirconia ceramic.</p><p><b>METHODS</b>Sixty 2.5 mm thick computer aided design and computer aided manufacture (CAD/CAM) zirconia ceramic (Vita Inceram YZ) plates were fired, polished and cleaned. Half of polished ceramic plates was sandblasted with 50 µm alumina particles at 0.3 MPa for 20 s. The surface roughness of polished and sandblasted ceramic surface were measured by 3D-laser scanning microscope, and the surface element weight and atom ratio of the ceramic surface were measured by energy disperse spectroscopy (EDS). Then polished and sandblasted ceramic plates were randomized into six groups. In Group 1 and 2 the polished and sandblasted ceramic plates were bonded irrespectively with conventional resin cement (DUOLINK). In Group 3 and 4 the ceramic plates were bonded with resin cement containing MDP (Panavia F), In Group 5 and 6 the specimens were pretreated with silane coupler acitivated by MDP (Clearfil Ceramic Primer), then bond with Panavia F. The specimens of each test group were then divided into two subgroups, and to received shear test after 0 and 10 000 time thermal cycle. The data was analyzed by one-way ANOVA and independent t test.</p><p><b>RESULTS</b>Comparing with polishing, sandblasting reduced the oxygen atom and weight ratio of zirconia ceramic surface (P < 0.001), and increased the zirconium atom and weight ratio (P < 0.001), meanwhile increased the surface roughness (P < 0.001). The bond strength between ceramic plates and resin cement in all test groups decreased after thermocycling (P < 0.001). All specimen in test group 1 and 2 lost bond, and the bond strength of test group 3 and 5 [(0.59 ± 0.17), (0.89 ± 0.84) MPa] were significantly lower than that of test group 4 and 6 [(14.63 ± 3.03), (16.64 ± 1.90) MPa], and the bond strength of test group 6 were significanlty higher than that of test group 4.</p><p><b>CONCLUSIONS</b>Sandblasting improves durability of bond between zirconia ceramic and resin cement containing MDP, not only by increasing the roughness and area of ceramic surface, but also by changing its surface element composition to obtain more chemical bond.</p>

The comparative research on resin bond strength and durability of two machinable glass ceramic / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of different silane couplers on bond strength and durability of two machinable glass ceramics to resin cement.</p><p><b>METHODS</b>Two machinable glass ceramics (A and B) were silanized by three silane couplers (A, B, C), and were bonded with a resin cement (G-CEM) to form micro-shear test specimens of six groups. The specimens of each group were subdivided into two subgroups, and their micro-shear bond strength was measured before and after 10000 thermal cycles. Bond strength data were analyzed by two-way ANOVA.</p><p><b>RESULTS</b>Before thermal cycles, the bond strength of ceramic A treated by silane coupler A was lower than that of ceramic B (P = 0.002). The bond strength of ceramic A treated by silane coupler C was significantly higher than that treated by silane coupler A and B (P = 0.014, P = 0.019). 10 000 thermal cycles obviously decreased the bond strength of all groups except the group of ceramic A treated by silane coupler B, and no significant difference was found between three silane coupler with either of two ceramic. However the bond strength of ceramic B treated by silane coupler B and C was significantly higher than that of ceramic A (P = 0.003, P = 0.027).</p><p><b>CONCLUSION</b>As well as the types of silane coupler, the type of ceramic could affect their bond strength and durability to resin cement.</p>

Research on the resin bond durability of glass-infiltrated alumina ceramic / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To analyze the effect of different silane coupling agents on the resin bond durability of glass-infiltrated alumina ceramic. Methods A glass-infiltrated alumina ceramic was silanized or not by three silane coupling agents. The treated ceramic surfaces were bonded with two resin cements. Their micro-bond strength were measured after 0, 30,000 thermal cycles.</p><p><b>RESULTS</b>Before thermal cycling, resin cement A had lowest bond strength to ceramic, and ceramic treated by silane coupling agent A with two cements had lower bond strength than those treated by silane coupling agent B and C. After thermal cycling, cement A had no bond strength with no treated ceramic, only ceramic treated by silane coupling agent A with two cements had more than 5 MPa bond strength.</p><p><b>CONCLUSION</b>The glass-infiltrated alumina cermaic treated by the silane coupling agent activated by 10-methacryloyloxydecyl-dihydrogen phosphate could obtain better bond durability with different type of resin cements.</p>

Effect of irradiation intensity on dual-cured resin/ceramic bond durability / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of light irradiation intensity on bond durability of dual-cured resin luting agents to silanized ceramics.</p><p><b>METHODS</b>Linkmax HV (LMHV), Nexus 2 (NX2), Variolink II HV (VL II HV) as dual-cured resin luting agents were bonded to silanized GN-I glass ceramics, and irradiated by 800, 310 and 80 mW x cm(-2) light intensity to form micro-shear test specimens. After 1, 90 d water storage, micro-shear bond strength of silanized resin/ceramic luting agent were measured. Data of each resin luting agent were analyzed by one-way ANOVA.</p><p><b>RESULTS</b>90 d water storage decreased significantly the bond strength of all test groups, and the weak of irradiation intensity did not deteriorate this reduction of bond strength of luting resin/cermaic, oppositely in which LMHV irradiated by 310 mW x cm(-2) light intensity and NX2 irradiated by 80 mW x cm(-2) showed the higher bond strength than that irradiated by 800 mW x cm(-2).</p><p><b>CONCLUSION</b>The weak of irradiation intensity does not affect the bond durability of dual-cured resin luting agents to silanized ceramics.</p>

Bond durability of self-adhesive resin cement to glass ceramic / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the bond durability of glass ceramic to self-adhesive and conventional resin cements.</p><p><b>METHODS</b>Maximum water sorption and solubility of two resin cements (A: self-adhesive type, G-CEM; B: conventional type, Linkmax HV) were measured during 6 week water storage. And their surface Knoop hardness number was measured at 0.5, 24 h and 6 week after irradiation. Sixty-four glass ceramic samples were or were not silanized with one of the three silane coupling agents (A: Monobond S; B: Clearfil Ceramic Primer; C: GC Ceramic Primer), and then cemented with two resin cements. The micro-bond strength between the two cements and glass ceramic were measured at baseline and after 30 000 thermal cycle.</p><p><b>RESULTS</b>Cement A had higher water sorption [(79.62 +/- 5.63) microg/mm³] and solubility [(4.78 +/- 3.33) microg/mm³] than cement B[(35.03 +/- 3.33) microg/mm³, (0.00 +/- 0.00) microg/mm³]. Cement A and B could achieve maximal surface hardness at 24 h after irradiation, and this was maintained during 6 week water storage. After 30 000 thermal cycle, the micro-bond strength between unsilanized glass ceramic and cement A or B was (0.00 +/- 0.00) MPa, and those between cement A and silanized glass ceramic with silane coupling agent A, B and C, were (2.86 +/- 3.25), (12.75 +/- 1.55) and (11.98 +/- 2.35) MPa respectively [for cement B, the data was (5.15 +/- 5.20), (10.94 +/- 3.30) and (14.18 +/- 3.13) MPa]. No significant diffrence was found between the micro-bond strength of cement A and that of cement B with glass ceramic.</p><p><b>CONCLUSIONS</b>Self-adhesive resin cement can achieve similar bond durability to glass ceramic as conventional resin cement does.</p>

Effect of hydrofluoric acid etching time on the resin bond durability of glass ceramic / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To analyze the effect of hydrofluoric acid (HFA) etching time on the resin bond durability of glass ceramic.</p><p><b>METHODS</b>Three groups of samples of machinable glass ceramic (ProCAD) were etched by 4.8% HFA for 0, 30 and 60 s respectively. The roughness parameters (Ra, Sm, S) and surface area of the samples, were measured with a 3D-laser scanning microscope. Then the ceramic surfaces were bonded with four resin cements (silane coupler/resin cement), which were Monobond S/Variolink II, Clearfil Ceramic Primer/Clearfil Esthetic Cement, GC Ceramic Primer/Linkmax HV, and Porcelain Liner M/SuperBond. The micro-bond strengths between the ceramic and the resin were tested at baseline and after the samples had been treated in 30000 thermal cycles.</p><p><b>RESULTS</b>The Ra [(3.89+/-1.94), (12.53+/-0.80), (13.58+/-1.10) microm] and surface area [(7.81+/-2.96), (30.18+/-2.05), (34.16+/-1.97) mm2] of ceramic increased with the increase of HFA etching time. The thermal cycling test reduced the bond strength of all test groups. The bond strength of Monobond S/Variolink II group [(3.59+/-3.51), (16.18+/-2.62), (20.33+/-2.45) MPa] and Clearfil Ceramic Primer/Clearfil Esthetic Cement group [(4.74+/-2.08), (7.77+/-1.55), (13.45+/-3.75) MPa] increased with the increase of HFA etching time; 30 s HFA etching group of Porcelain Liner M/SuperBond had higher bond strength [(22.00+/-1.64) MPa] than its 0 s HFA etching group [(12.96+/-4.17) MPa], and no significant difference was found between the 30 s and 60 s HFA etching groups of Porcelain Liner M/SuperBond [(20.42+/-3.01) MPa]. HFA etching time had no effect on the bond strength of GC Ceramic Primer/Linkmax HV.</p><p><b>CONCLUSIONS</b>HFA etching can improve the resin bond durability of glass ceramic, and the etching time is not only related to the change of ceramic surface roughness and area, but also to the characteristics of resins.</p>