Dental Bonding ; methods ; Dentin ; Dentin-Bonding Agents ; chemistry ; Electricity ; Humans

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 investigate the effect of multiple coatings of the one-step self-etching adhesive on immediate microtensile bond strength to primary dentin.

METHODSTwelve caries-free human primary molars were randomly divided into 2 groups with 6 teeth each. In group 1, each tooth was hemisected into two halves. One half was assigned to control subgroup 1, which was bonded with a single-step self-etching adhesive according to the manufacturer's instructions; the other half was assigned to experimental subgroup 1 in which the adhesive was applied three times before light curing. In group 2, the teeth were also hemisected into two halves. One half was assigned to control subgroup 2, which was bonded with the single-step self-etching adhesive according to the manufacturer's instructions; the other half was assigned to experimental subgroup 2 in which three layers of adhesive were applied with light curing each successive layer. Microtensile bond strength was immediately tested after specimen preparation.

RESULTSWhen the adhesive was applied three times before light curing, the bond strength of the experimental subgroup 1 (n=33, 57.49 +/-11.61 MPa) was higher than that of the control subgroup 1 (n=31, 49.71 +/-11.43 MPa, P<0.05). When using the technique of applying multiple layers of adhesive with light curing each successive layer, no difference of immediate bond strength was observed between the control subgroup 2 and the experimental subgroup 2 (P>0.05).

CONCLUSIONstrength to primary dentin when using the technique of light-curing after applying three layers of adhesive.

Adhesives ; chemistry ; Dental Bonding ; Dental Stress Analysis ; Dentin ; chemistry ; Dentin-Bonding Agents ; chemistry ; Humans ; In Vitro Techniques ; Methacrylates ; 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

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

10-methacryloyloxydecyl dihydrogen phosphate was synthesized from the reaction of phosphoryl chloride with methylacrylic acid and 1, 10-decanediol. The structure of product was characterized by 1H-NMR, 31P-NMR and MS. The effect of this product on the bond durability of composite resin joined to enamel, dentin and dental alloy was evaluated by the test of shear strengths. 10-methacryloyloxydecyl dihydrogen phosphate significantly elevated the bond strength of the composite resin joined to enamel, dentin, Ti alloy and Co-Cr alloy; the relevant shear strengths were 13.5, 11.2, 16.2 and 18.1 MPa, respectively.
Dental Bonding ; Dentin-Bonding Agents ; chemical synthesis ; chemistry ; Humans ; Methacrylates ; chemical synthesis ; chemistry ; Shear Strength

Dentin matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which might result in reduced bond strength. Most MMPs are synthesized and released from odontoblasts in the form of proenzymes, requiring activation to degrade extracellular matrix components. Unfortunately, they can be activated by modem self-etch and etch-and-rinse adhesives. The aim of this review is to summarize the current knowledge of the role of dentinal host-derived MMPs in dentin matrix degradation. We also discuss various available MMP inhibitors, especially chlorhexidine, and suggest that they could provide a potential pathway for inhibiting collagen degradation in bonding interfaces thereby increasing dentin bonding durability.
Chlorhexidine ; pharmacology ; Collagen ; metabolism ; ultrastructure ; Dental Bonding ; Dentin ; enzymology ; ultrastructure ; Dentin-Bonding Agents ; chemistry ; Enzyme Inhibitors ; pharmacology ; Humans ; Hydrolysis ; Matrix Metalloproteinase Inhibitors ; Matrix Metalloproteinases ; metabolism ; Resin Cements ; chemistry

OBJECTIVETo evaluate in vitro the microtensile bond strengths of three dentin adhesive systems and their respective fracture modes.

METHODSA total of 15 intact young human premolars extracted for orthodontic reasons were used. The enamel of occlusal surfaces of these premolar teeth was removed and superficial dentine was exposed, finished with wet 600-grit silicon carbide paper. And then these teeth were randomly divided into three groups. A block of composite resin was bonded respectively with three dentin adhesive systems: All-bond 2 (Group AB(2)), Fluoro-Bond (Group FB) and Xeno III (Group Xeno) according to manufacturers' instructions. The bonded teeth were kept in distilled water for 24 h at 37 degrees C. The roots were removed from the remaining crown approximately 1 - 2 mm below the cemento-enamel junction with a slow-speed diamond saw. The teeth were sectioned to obtain bar-shaped specimens, whose bonded surface areas were about 0.8 mm(2). The specimens were stressed at a crosshead speed of 1 mm/min until rupture of the bond. SEM was used to observe the fracture modes. The mean bond strengths were compared using one-way ANOVA and LSD tests. The frequency of fracture modes was compared using Krukal-Wallis and Mann-Whitney U-test.

RESULTSMean microtensile bond strengths were (29.56 +/- 5.47) MPa for Group AB(2), (15.81 +/- 7.67) MPa for Group Xeno, and (14.61 +/- 4.50) MPa for Group FB. The bond strength of Group AB(2) was greater than those of the other two groups (P < 0.01). The bond strengths of Group Xeno and Group FB were not significantly different. SEM examination indicated that the adhesive failure was the most mode of fracture.

CONCLUSIONSThe microtensil bond strengths of three dentin adhesive systems to normal human dentine were different and the total-etching adhesive All-Bond 2 exhibited the greatest bond strength. It was recommended that dentin adhesive agent should be used according to clinical situation.

Adolescent ; Dental Bonding ; Dentin ; ultrastructure ; Dentin-Bonding Agents ; chemistry ; Humans ; In Vitro Techniques ; Materials Testing ; Microscopy, Electron, Scanning ; Tensile Strength ; Young Adult

OBJECTIVETo evaluate the nanoleakage and ultramorphology of four self-etching adhesives.

METHODSSixteen freshly extracted, caries-free human third molars were selected. A flat dentin surface was exposed by removing occlusal enamel. All teeth were randomly divided into four groups acorrding to four different self-etch adhesive: Adper Prompt (A), iBond (B), Xeno III (C) and SE Bond (D). The dentin were bonded with dentin adhesive system according to manufacturer's directions. Composite layers were built up incrementally. The specimens were sectioned longitudinally across the resin-dentin interface into 4.0 mm×0.9 mm sticks and then traced with ammoniacal silver solution. Epoxy resin-embedded sections were prepared for transmission electron microscope (TEM) to observe nanoleakage. The images were qualitatively compared by NIH software, and data was analyzed by SPSS.

RESULTSDifferent thickness of hybrid layer and adhesives layer were observed for each adhesive. The hybrid layer of A, C was thicker than that of B, D, and adhesive layer of D was thicker than the others. The extent of nanoleakage varied among different adhesives: A (45.02 ± 9.49), B (43.97 ± 8.55), C (27.02 ± 10.86), D (12.94 ± 2.07). D presented significantly less silver deposition than any of the others did (P < 0.05).

CONCLUSIONSThe thickness of hybrid layer and adhesive layer vary among the four adhesives. The shape and extent of nanoleakage of each adhesive are also different. Two-step system shows less nanoleakage than one-step systems do.

Acid Etching, Dental ; Adhesives ; chemistry ; Dental Leakage ; pathology ; Dentin ; ultrastructure ; Dentin-Bonding Agents ; chemistry ; Humans ; Methacrylates ; chemistry ; Microscopy, Electron, Transmission ; Molar, Third ; Resin Cements ; chemistry

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