The existing dentin bonding systems based on acid-etching technique lead to the loss of both extrafibrillar and intrafibrillar minerals from dentin collagen, causing excessive demineralization. Because resin monomers can not infiltrate the intrafibrillar spaces of demineralized collagen matrix, degradation of exposed collagen and resin hydrolysis subsequently occur within the hybrid layer, which seriously jeopardizing the longevity of resin-dentin bonding. Collagen extrafibrillar demineralization can effectively avoid the structural defects within the resin-dentin interface caused by acid-etching technique and improve the durability of resin-dentin bonding, by preserving intrafibrillar minerals and selectively demineralizing extrafibrillar dentin. The mechanism and research progress of collagen extrafibrillar demineralization in dentin bonding are reviewed in the paper.
Humans ; Collagen ; Dental Bonding ; Dentin/chemistry* ; Dentin-Bonding Agents/chemistry* ; Materials Testing ; Minerals ; Resin Cements/chemistry* ; Tooth Demineralization

Objective: To evaluate the effect of shear bond strength between resin cement and zirconia using SiO₂-ZrO₂ slurry coating. Methods: One hundred and forty pre-sintered zirconia discs were randomly divided into seven groups (n=20) according to the surface treatments: AS (as-sintered), SB (sand blasting with Al₂O₃), 2SiO₂-1ZrO₂ (2∶1 mole ratio SiO₂-ZrO₂ coating), 1SiO₂-1ZrO₂ (mole ratio 1∶1 SiO₂-ZrO₂ coating), 1SiO₂-2ZrO₂ (mole ratio 1∶2 SiO₂-ZrO₂ coating), 1SiO₂-3ZrO₂ (mole ratio 1∶3 SiO₂-ZrO₂ coating), 1SiO₂-4ZrO₂ (mole ratio 1∶4 SiO₂-ZrO₂ coating). Each zirconia disc was bonded to composite resin cylinder using resin cement. All specimens were stored in distilled water (37 ℃, 24 h). Each group was divided into two subgroups in which half specimens were tested using universal testing machine and another half specimens accepted artificial aging of 5 000 times thermocycling then tested. Scaning electron microscopy (SEM) was used to observe the micro-morphology of coating surface etched by hydrofluoric acid,then the coating thickness was measured. Results: Before artificial aging, 1SiO₂-1ZrO₂ showed a higher shear bond strength [(41.69±6.28) MPa] than all the other group (P<0.05). 1SiO₂-2ZrO₂ gained a higher strength than AS, SB, 1SiO₂-3ZrO₂ and 1SiO₂-4ZrO₂ (P<0.05). However, 1SiO₂-2ZrO₂ did not get a significant higher shear bond strength than 2SiO₂-1ZrO₂ (P>0.05). No significant differences were found among SB, 2SiO₂-1ZrO₂ and 1SiO₂-3ZrO₂ (P>0.05). After artificial aging, shear bond strength of all groups were decreased significantly besides 2SiO₂-1ZrO₂. 2SiO₂-1ZrO₂, 1SiO₂-1ZrO₂ and 1SiO₂-2ZrO₂ [(24.13±5.50), (22.28±4.40), (23.11±4.80) MPa] showed higher shear bond strength than SB and 1SiO₂-3ZrO₂ (P<0.05),no intergroup differences were observed (P>0.05). Shear bond strength of AS and 1SiO₂-4ZrO₂ fell to 0 MPa approximately. The SEM images of etched coating surface showed contraction fissure due to different thermal expansion coefficient between SiO₂ and ZrO₂ and intercrystal pores of zirconia. The thickness of coating was measured to be less than 30 μm. Conclusions: Mole ratio 1∶1 SiO₂-1ZrO₂ slurry coating showed the highest shear bond strength of resin cement to zirconia.
Dental Bonding ; Materials Testing ; Resin Cements/chemistry* ; Silicon Dioxide ; Surface Properties ; Zirconium

Biofilms at the tooth-restoration bonded interface can produce acids and cause recurrent caries. Recurrent caries is a primary reason for restoration failures. The objectives of this study were to synthesize a novel bioactive dental bonding agent containing dimethylaminohexadecyl methacrylate (DMAHDM) and 2-methacryloyloxyethyl phosphorylcholine (MPC) to inhibit biofilm formation at the tooth-restoration margin and to investigate the effects of water-aging for 6 months on the dentin bond strength and protein-repellent and antibacterial durability. A protein-repellent agent (MPC) and antibacterial agent (DMAHDM) were added to a Scotchbond multi-purpose (SBMP) primer and adhesive. Specimens were stored in water at 37 °C for 1, 30, 90, or 180 days (d). At the end of each time period, the dentin bond strength and protein-repellent and antibacterial properties were evaluated. Protein attachment onto resin specimens was measured by the micro-bicinchoninic acid approach. A dental plaque microcosm biofilm model was used to test the biofilm response. The SBMP + MPC + DMAHDM group showed no decline in dentin bond strength after water-aging for 6 months, which was significantly higher than that of the control (P < 0.05). The SBMP + MPC + DMAHDM group had protein adhesion that was only 1/20 of that of the SBMP control (P < 0.05). Incorporation of MPC and DMAHDM into SBMP provided a synergistic effect on biofilm reduction. The antibacterial effect and resistance to protein adsorption exhibited no decrease from 1 to 180 d (P > 0.1). In conclusion, a bonding agent with MPC and DMAHDM achieved a durable dentin bond strength and long-term resistance to proteins and oral bacteria. The novel dental bonding agent is promising for applications in preventive and restorative dentistry to reduce biofilm formation at the tooth-restoration margin.
Anti-Infective Agents ; chemistry ; pharmacology ; Biofilms ; drug effects ; Dental Bonding ; Dentin-Bonding Agents ; chemistry ; pharmacology ; Materials Testing ; Methacrylates ; chemistry ; pharmacology ; Phosphorylcholine ; analogs & derivatives ; chemistry ; pharmacology ; Resin Cements ; Shear Strength ; Surface Properties ; Water

The purpose of this study was to assess the influence of the types and thicknesses of glass ceramic plates on light transmittance and compare the degrees of conversion (DC) of resin cement under the ceramic materials. Three ceramic plates with thicknesses of 0.5, 1.0, 2.0, and 4.0 mm were fabricated from each of five commercial ceramic blocks in shade A2: high-translucency and low-translucency IPS Empress CAD (Emp_HT and Emp_LT); high-translucency and low-translucency IPS e.max CAD (Emx_HT and Emx_LT); and Vita Mark II (Vita). The translucency parameter was obtained using a colorimeter. The light transmittance rate was measured using a photodetector attached to an optical power meter. The DC of a resin cement (Variolink N) underneath the ceramic plates was examined by Fourier transform infrared spectroscopy. The translucency parameter, light transmittance rate, and DC showed significant differences by ceramic type and thickness (P < 0.05). The Emp_HT specimens showed the highest light transmission and DCs, and the Emx_LT showed the least light transmission and the lowest DCs. The high-translucency Empress showed significantly higher DCs than the low-translucency types (P < 0.05), but there was no significant difference in e.max (P > 0.05). Both type and thickness of the glass ceramics significantly influenced the light transmittance and DC of the light-cured resin cement beneath the ceramic of the same shade.
Aluminum Silicates ; Ceramics ; chemistry ; Color ; Dental Materials ; chemistry ; Dental Porcelain ; Light ; Materials Testing ; Resin Cements ; chemistry ; Spectroscopy, Fourier Transform Infrared ; Surface Properties

OBJECTIVETo evaluate the effect of 2-methacryloyloxyethyl phosphorylcholine (MPC) and nanoparticles of amorphous calcium phosphate (NACP) on the protein-repellent property of dental adhesive.

METHODSMPC and NACP were incorporated into SBMP as the test group. Scotchbond Multi-Purpose (SBMP) was used as control group. Human dentin shear bond strengths were measured. Protein adsorption onto samples was determined by micro bicinchoninic acid (BCA) method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate biofilm viability.

RESULTSThe dentin bond strength of modified group was (28.7±2.2) MPa, which was not significantly different from that of the SBMP control group. The amount of protein adsorption in the modified group and the SBMP control group were (0.21±0.02) µg/cm(2) and (4.17±0.45) µg/cm(2) respectively. Lactic acid production of biofilms in modified group and SBMP control were (7.71 ± 1.01) mmol/L and (19.18 ± 2.34) mmol/L repectively.

CONCLUSIONSMPC-NACP based dental adhesive greatly reduce the protein adsorption and bacterial adhesion, without compromising dentin shear bond strength. This novel bonding agent may have wide application.

Adsorption ; Biofilms ; drug effects ; growth & development ; Calcium Phosphates ; pharmacology ; Dental Cements ; pharmacology ; Dental Plaque ; Dentin ; chemistry ; Humans ; Lactic Acid ; biosynthesis ; Methacrylates ; pharmacology ; Nanoparticles ; Phosphorylcholine ; analogs & derivatives ; pharmacology ; Resin Cements ; pharmacology ; Saliva ; Tensile Strength

OBJECTIVETo investigate the effect of epigallocatechin-3-gallate (EGCG) on biomodification of demineralized dentine substrate, in its permeability, hydrophobicity, and inhibition ability to collagen enzymatic degradation.

METHODSThe dentine substrates were treated with simulated pulpal pressure created by mixtures of 0.02%, 0.1% EGCG/bovine serum albumin (BSA) in acidic environment (pH4.4) for 48 h. A fluid-transport model was used to measure the fluid permeability through demineralized dentine substrate. Positive replicas of dentine substrate were fabricated before and after being subjected to acidic environment for scanning electron microscope (SEM) examination. The blank group contained no EGCG and the positive group were treated with Gluma desensitizer. Static contact angle measurements on demineralized dentin and 0.1% EGCG primed dentin were performed by contact angle analyzer. The priming time were 60 s, 120 s, 0.5 h, 1 h. Dentine specimens bonded with Adper single bond 2 were subjected to 100 mg/L collagenase and observed under SEM. Resin-bonded specimens (with 0.02%, 0.1%, 0.5% EGCG priming, or without EGCG priming) were created for micro-tensile bond strength evaluation (MTBS). Resin-bonded specimens after thermol cycling were created for MTBS evaluation.

RESULTSThe fluid permeability in the blank control group increased ([151.3±22.3]%), the fluid permeability in 0.1% EGCG/BSA group decreased ([23.7±6.3]%). Compared to the blank control group, the contact angle of 120 s, 0.5 h, 1 h groups increased by 31.0%, 53.5%, 57.8% in deep dentin and 37.4%, 59.3%, 62.4% in shallow dentin. The SEM examination showed that 0.1% and 0.5% EGCG priming for 120 s significantly increased dentin collagen's resistance to collagenase. The immediate MTBS of 0.1% and 0.5% EGCG groups were (29.4±4.8) and (19.8± 4.9) MPa. After thermol cycling, the MTBS of 0.1% and 0.5% EGCG groups were (19.9±5.1) and (15.3± 6.3) MPa.

CONCLUSIONSUnder acidic environment (pH4.4), the 0.1% EGCG can reduce dentine permeability under acidic environment. The 0.1% EGCG can increase hydrophobicity of dentin substrate, and strengthen dentin substrate's resistance to collagenase hydrolysis, thus increased the resin-dentin bonding durability.

Acid Etching, Dental ; Catechin ; analogs & derivatives ; pharmacology ; Collagen ; chemistry ; drug effects ; Collagenases ; pharmacology ; Composite Resins ; Dental Bonding ; Dental Cements ; Dental Pulp ; Dentin ; chemistry ; drug effects ; Dentin Permeability ; drug effects ; Dentin-Bonding Agents ; Glutaral ; pharmacology ; Hydrogen-Ion Concentration ; Hydrolysis ; Methacrylates ; pharmacology ; Microscopy, Electron, Scanning ; Pressure ; Resin Cements ; Serum Albumin, Bovine ; pharmacology ; Tensile Strength ; Time Factors

OBJECTIVETo evaluate the adhesive interface and micro-tensile bond strength (μTBS) of infiltrating resin directly bonded to normal dentin.

METHODSTwenty extracted human molars were collected and ground to expose fresh dentin surface. An infiltrating resin (ICON, DMG, Germany) was served as experimental group and Clearfil SE Bond adhesive (Kuraray, Japan) as control group. Following the application of primer (Kuraray, Japan), the specimens were applied infiltrating resin or adhesive respectively and blocks of composite resin were built up. The adhesive interfaces were observed using scanning electron microscope (SEM) and the μTBS was measured by micro-tensile test before and after thermal cycling.

RESULTSThe infiltrating resin could penetrate into micro-structure of dentin created by SE Bond primer. A layer of about 180 μm-long and dense resin tags was observed under SEM in infiltrating resin group. The μTBSs were (35 ± 10) MPa before and (35 ± 9) MPa after thermal cycling respectively in infiltrating resin group, and the difference was not statistically significant (P>0.05). The μTBSs were (38±8) MPa before and (24±7) MPa after thermal cycling respectively in control group, and the difference was statistically significant (P<0.05). After thermal cycling, the μTBS of infiltrating resin group was significant higher than that of control group.

CONCLUSIONSThe infiltrating resin could penetrate into the micro-structure of dentin created by SE Bond primer. The bond strength and the bonding durability of infiltrating resin were similar to that of SE Bond adhesive.

Adhesives ; chemistry ; Composite Resins ; chemistry ; Dental Bonding ; Dentin ; Dentin-Bonding Agents ; chemistry ; Humans ; In Vitro Techniques ; Japan ; Materials Testing ; Microscopy, Electron, Scanning ; Molar ; Resin Cements ; chemistry ; Surface Properties ; 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

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

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