OBJECTIVEThis study aims to investigate the color stability of ceromer with different thicknesses and different types of resin adhesive materials after accelerated aging and provide references for clinical application and selections.

METHODSNine groups of experimental samples were used, and each group contained five samples. We made joint samples with ceromer having three different thicknesses (1.00, 0.75, 0.50 mm) combined with three different resin adhesive materials (RelyX Veneer, RelyX Unicem, Filtek Z350 Flow), respectively. All samples were placed into Xenon Lamp Aging Instrument to implement accelerated aging. Spectrophotometer was used to measure the lightness (L*), red green color value (a*), and blue yellow color value (b*) of all samples before and after accelerated aging. The change of lightness (ΔL), red green color value (Δa), blue yellow color value (Δb), and color variation (ΔE) were also calculated. We investigated the influence of ceromer veneer thicknesses and resin adhesive material types on color variation by two-factor analysis of variance.

RESULTSThe thickness and type factors showed significant influence on ΔE values, and exhibited interactions (P < 0.05). The ΔE values of all experimental groups were lower than 3.3. After the accelerated aging process, all L*, a*, and b* values of the experimental groups decreased and the ΔL values were lower than 2.0.

CONCLUSIONCeromer veneer thickness and resin adhesive material types could affect the color stability of ceromer veneer and resin adhesive materials. The changes in lightness and color in ceromer veneer and resin adhesive materials are considered clinically acceptable after accelerated aging.

Ceramics ; Color ; Composite Resins ; Dental Cements ; chemistry ; Light ; Resin Cements

BACKGROUNDThe lithium disilicate-based ceramic is a newly developed all-ceramic material, which is lithium disilicate-based and could be used for fabricating almost all kinds of restorations. The extent of light attenuation by ceramic material was material-dependent. Ceramic materials with different crystal composition or crystalline content would exhibit distinct light-absorbing characteristics. The aim of this study was to analyze the influence of ceramic thickness and light-curing time on the polymerization of a dual-curing resin luting material with a lithium disilicate-based ceramic.

METHODSA lithium disilicate-based ceramic was used in this study. The light attenuation caused by ceramic with different thickness was determined using a spectral radiometer. The commercial dual-cured resin cement was light-cured directly or through ceramic discs with different thickness (1, 2 and 3 mm, respectively) for different times (10, 20, 30, 40, 50 and 60 seconds, respectively). The polymerization efficiency of resin cement was expressed in terms as Vickers hardness (VHN) measured after 24 hours storage. Two-way analysis of variance (ANOVA) and Tukey's HSD tests were used to determine differences.

RESULTSIntensity of polymerizing light transmitted through ceramic discs was reduced from 584 mW/cm(2) to about 216 mW/cm(2)2, 80 mW/cm(2) and 52 mW/cm(2) at thicknesses of 1 mm, 2 mm and 3 mm, respectively. Resin cement specimens self-cured alone showed significantly lower hardness values. When resin cement was light-cured through ceramic discs with a thickness of 1 mm, 2 mm and 3 mm, no further increasing in hardness values was observed when light-curing time was more than 30 seconds, 40 seconds and 60 seconds, respectively.

CONCLUSIONSWithin the limitation of the present study, ceramic thickness and light-curing time had remarkable influence on the polymerization of dual-cured resin cement. When resin cement is light-cured beneath a lithium disilicate ceramic with different thickness, prolonging light-curing time accordingly may still be necessary to insure complete polymerization.

Ceramics ; chemistry ; Dental Porcelain ; chemistry ; Light ; Resin Cements ; chemistry

OBJECTIVETo 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.

RESULTSBefore 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.

CONCLUSIONThe 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.

Aluminum Oxide ; chemistry ; Ceramics ; chemistry ; Dental Bonding ; Glass ; chemistry ; Resin Cements ; chemistry

OBJECTIVEThis study aims to evaluate the bond strength of a self-adhesive resin cement to dentin by ethylene diamine tetraacetic acid (EDTA) and NaClO.

METHODSTwenty-seven freshly extracted non-carious human premolars were prepared to expose the buccal dentin and randomly divided into three groups: control group (A group), EDTA group (B group) and NaClO group (C group). All teeth were bonded to dentin using a self-adhesive resin cement after the teeth in the A group were processed with distilled water. The B and C group were processed with 3%EDTA and 1%NaClO, respectively. After 24 hours at 37 °C water, the shear bond strengths of the twenty-four specimens were measured. All statistical analysis was performed using SPSS 17.0 software package. Each fractured specimen was examined under dental microscope. Three new specimens were cut, and the morphologies of the cement-dentin interface were observed under scanning electron microscope (SEM).

RESULTSThe shear bond strength in the A group, B group and C group was (8.55±0.63), (8.47±0.56) and (12.97± 0.59) MPa, respectively. The difference between A group and B group was no statistically significant (P>0.05), whereas the difference between C group and B group (or A group) was statistically significant (P<0.05). SEM observation of the cement-dentin interface in the C group showed good adaptation, but resin tags were not observed. The other two groups showed poor bonding interface. Most of the fractured adhesive dentin surfaces exhibited cohesive failure in the A group and B group. All the fractured adhesive dentin surfaces exhibited cohesive failure in the C group.

CONCLUSION1% NaClO can increase the bond strength of self-adhesive resin cement to dentin, but 3%EDTA has no effect.

Adhesives ; Dental Bonding ; Dental Stress Analysis ; Dentin ; chemistry ; Dentin-Bonding Agents ; Detergents ; chemistry ; Humans ; Resin Cements

OBJECTIVETo evaluate the effect of desensitizer on shear bond strength of adhesive system.

METHODSTwenty specimens were made and divided randomly into an experiment group and a control group. In the experiment group, the dentin bonding surface was applied with Green Or and in the control, the dentin bonding surface was untreated. The IPS-Empress specimens were bonded to the dentin bonding specimens using Variolink II adhesive system. The shear bond strength of all testing samples was determined with Instron testing machine. The surfaces of the drawing sections were observed using the scanning electron microscope (SEM).

RESULTSThe shear bond strength of the experimental group and the control group was (5.53 +/- 0.96) MPa and (7.32 +/- 1.34) MPa respectively and there was statistically significant difference between two groups (P = 0.003). In the experimental group, adhesive failure was the most prevalent type of failure, while in the control group, cohesive failure was the most prevalent type.

CONCLUSIONSThe application of Green Or on the dentin bonding surface decreased the shear bond strength between dentin and IPS-Empress specimens when using Variolink II adhesive system.

Dental Bonding ; Dental Stress Analysis ; Dentin-Bonding Agents ; chemistry ; Materials Testing ; Resin Cements ; chemistry ; Surface Properties

In order to improve its dispersion condition in dental composite resin and enhance its interaction with the matrix, single-walled carbon nanotubes(SWNTs) were refluxed and oxidized, then treated by APTE. Their outer surface were coated by nano-SiO2 particles using sol-gel process, then further treated by organosilanes ATES. IR and TEM were used to analyze modification results. TEM pictures showed nano-particles were on the surface of SWNTs; IR showed characteristic adsorbing bands of SiO2. Composite resin specimen with modified SWNTs was prepared and examined by TEM. SWNTs were detected in composite resin matrix among other inorganic fillers.
Composite Resins ; chemistry ; Dental Materials ; chemistry ; Humans ; Nanotubes, Carbon ; chemistry ; Resin Cements ; chemistry ; Silicon Dioxide ; chemistry ; Surface Properties ; Tensile Strength

OBJECTIVETo evaluate the effect of aging of the composite and the adhesive interface on composite-composite repair bond strength.

METHODSMethacrylate-based composite resin (Clearfil AP-X, composite A) and silorane-based composite resin (Filtek P90, composite B) and their corresponding adhesive, Clearfil SE Bond (adhesive a) and Filtek P90 System Adhesive (adhesive b), were selected in this study. Twenty-four substrates were prepared from composite A or B separately and divided into three groups, each group had 8 substrates: group one, new composites were adhered to the substrates with the use of adhesive a or b, followed by cutting the blocks into sticks; group two, new composites were adhered to the substrates using adhesive a or b, followed by cutting into sticks and thermal cycling; group three, substrates were thermocycled, then polished and adhered new composites using adhesive a or b, followed by cutting into sticks. Each group had 8 combinations of substrate(A, B)-adhesive(a, b)-repair composite (A, B). Fifteen sticks without flaws in each combination of 3 groups were selected utilizing stereomicroscope. The data were analyzed by independent samples t test.

RESULTSIn group two, the microtensile strength(MS) of combinations using adhesive a and composite A or B to repair [A-a-A: (45.0 ± 3.2) MPa, B-a-A: (41.7 ± 3.3) MPa, A-a-B: (28.6 ± 3.9) MPa, B-a-B: (47.7 ± 6.6) MPa], and using adhesive b and composite A to repair [A-b-A: (44.2 ± 4.7) MPa, B-b-A: (38.0 ± 3.2) MPa] decreased significantly compared with corresponding combinations in group 1[A-a-A: (70.7 ± 5.5) MPa, B-a-A: (60.3 ± 5.1) MPa, A-a-B: (44.2 ± 1.6) MPa, B-a-B: (54.1 ± 3.2) MPa, A-b-A: (65.6 ± 7.2) MPa, B-b-A: (59.1 ± 4.1) MPa] (P<0.05). However, there was no significant difference between the MS of combinations using adhesive b and composite B to repair in group one and the MS of combinations in group two (P>0.05). The MS of all combinations in group three decreased significantly (P<0.05).

CONCLUSIONSAging of the composite and the adhesive interface might affect the composite-composite repair bond strength.

Composite Resins ; chemistry ; Dental Bonding ; Dental Cements ; chemistry ; Dental Stress Analysis ; methods ; Hot Temperature ; Humans ; Methacrylates ; chemistry ; Resin Cements ; chemistry ; Silorane Resins ; chemistry ; Tensile Strength

OBJECTIVETo evaluate the effect of base layer thickness of DyadFlow(DF) self-adhesive resin on dentin bonding strength.

METHODSTwenty extracted intact human molars were randomly selected and the occlusal surface of each molar was prepared by removing the enamel and exposing the dentin surface. The prepared molars were divided, randomly and equally, into 4 groups. For groups G0.5, G1.0 and G2.0, DF was applied directly on the dentin surfaces following the manufacturer's instruction, and for group GOB, OptiBond All-in-One(OB) self etching adhesive was applied on the dentin surface before using DF. The base layer thickness of DF was 0.5 mm, 1.0 mm, 2.0 mm, 2.0 mm for groups G0.5, G1.0, G2.0 and GOB, respectively. Composite crown were built up on each tooth, then the samples were sectioned longitudinally into sticks with proximately 1.0 mm2 bonding area(for microtensile bond strength[MTBS] testing) or slabs (for bonding interface observation with SEM). Fifteen sticks were obtained for each group. The fracture surface was also observed using SEM and the fracture type of each specimen was determined.

RESULTSThe MTBS were: GOB (20.19±3.11) MPa>G0.5 (8.65±1.58) MPa>G1.0 (6.65±1.13) MPa>G2.0 (5.70±0.60) MPa(P<0.05). Bonding interface fracture B2 was most frequently observed for all groups: G0.5: 14/15, G1.0: 13/15, G2.0: 14/15 and GOB: 13/15.

CONCLUSIONSThe MTBS decreased when the base layer thickness of DF increased. Direct application of DF self-adhesive resin on dentin surface adhesive restorations should be concerned.

Adhesives ; chemistry ; Crowns ; Dental Bonding ; Dental Enamel ; Dentin ; chemistry ; Dentin-Bonding Agents ; chemistry ; Humans ; Molar ; Resin Cements ; chemistry ; Tensile Strength

OBJECTIVETo study the effect of pre-restoration bleaching treatment on tensile strength of resin bonding agents to deep enamel and its duration, and to estimate the optimal timing of porcelain veneers bonding operation after bleaching treatment.

METHODSA total of 96 extracted human permanent teeth were allocated into 6 groups, 16 teeth for each. In 5 study groups, 80 teeth were bleached using 35% hydrogen peroxide activated by cold light. Right after bleaching and at 1, 4, 7, and 14 days after bleaching, the teeth were prepared with removal of 0.6 to 0.8 mm depth of enamel respectively. And then each study group was divided into two subgroups and bonded with resin bonding agents A (One-step plus) and B (Single bond). In the control group, 16 unbleached teeth were divided into two subgroups and bonded with the two bonding agents respectively. The tensile bonding strength was measured.

RESULTSThe tensile strength was [(17.79 +/- 3.53) and (19.41 +/- 3.37) MPa], [(17.50 +/- 4.29) and (19.66 +/- 3.48) MPa], and [(18.39 +/- 3.58) and (19.53 +/- 3.21) MPa] right after bleaching 0 day, 1 day, and 4 days, which were significantly smaller (about 30%) than that of the control group [(25.94 +/- 4.88) and (28.02 +/- 4.36) MPa] (P < 0.001). At 7 days after bleaching the tensile strength [(22.46 +/- 3.98) and (23.74 +/- 5.04) MPa] reached 87% and 85% of that in the control(P > 0.01). At 14 days after bleaching treatment, the strength [(26.03 +/- 4.47) and (27.88 +/- 4.78) MPa] reached the same level as that in the control (P > 0.01). There was no significant difference in bonding tensile strength between the two resin bonding agents.

CONCLUSIONSThe bonding strength of resin bonding agents to deep enamel was low during 2 weeks after bleaching treatment. It is suggested that porcelain veneer bonding operation should be performed till 2 weeks after bleaching treatment.

Dental Bonding ; Dental Enamel ; physiology ; Humans ; Resin Cements ; chemistry ; Tensile Strength ; Tooth Bleaching

OBJECTIVETo evaluate the bond durability of glass ceramic to self-adhesive and conventional resin cements.

METHODSMaximum 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.

RESULTSCement 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.

CONCLUSIONSSelf-adhesive resin cement can achieve similar bond durability to glass ceramic as conventional resin cement does.

Adhesives ; Dental Bonding ; Dental Porcelain ; Glass ; Hardness ; Materials Testing ; Resin Cements ; chemistry ; Shear Strength