An ex vivo assessment of a resin-modified glass ionomer cement in relation to bonding technique.
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OBJECTIVE: This study assessed a resin modified glass ionomer bonding system, Fuji ortho L.C. using different bonding techniques and compared it with a composite control (Transbond). DESIGN: Ex vivo study. Twenty extracted premolar teeth in each group were bonded as follows: (i) Group 1 Control (Transbond); (ii) Group 2 Fuji ortho L.C. without an etch procedure/wet enamel surface; (iii) Group 3 Fuji ortho L.C. without an etch procedure/dry enamel surface; (iv) Group 4 Fuji ortho L.C. using a conventional acid etch technique. OUTCOME: Shear bond strength, site of bond failure and adhesive remnant index. RESULTS: Brackets bonded as recommended by the manufacturer (Group 2) have significantly (p < 0.001) lower bond strengths compared with the control (Group 1). Bonding with an etch technique (Group 4) will significantly (p < 0.001) increase the bond strength compared with the other Fuji groups. All the Fuji groups tended to fail at the enamel/resin interface with lower ARI scores compared with the control. CONCLUSION: The lower bond strength of Fuji ortho L.C. would limit its use as a routine bonding agent. When bonded with an acid etch technique, the bond strength may be sufficient for low loading situations such as the upper anterior teeth. (+info)
The bonding of composite resin to moist enamel.
(18/389)
OBJECTIVE: To determine the effect on the bond strength of modern dentine bonding agents to etched enamel of surface contamination with water. DESIGN: Fifteen bond strength measurements were made for bonds prepared to both moist and dry etched enamel for each of three test and one control materials. RESULTS: For two materials (Scotchbond 1 and Prime and Bond 2.1) the bond strength was not affected by the presence of water on the etched enamel surface. A mean bond strength in excess of 25 MPa was achieved for both materials under all conditions. One material (Optibond Solo) showed a 30% increase in bond strength when bonds were formed under wet condition (21.10 MPa compared with 15.35 MPa). The bond strength of the control material, a conventional unfilled bonding resin, decreased markedly with aqueous contamination (9.14 MPa compared with 26.75 MPa). CONCLUSION: Etched enamel should be rehydrated routinely prior to bonding composite resin to its surface using a water displacing dentine bonding system. (+info)
The shear bond strength of composite brackets on porcelain teeth.
(19/389)
Recent advances in materials and techniques suggest that direct bonding of orthodontic attachments to surfaces other than enamel may now be possible. To test the effectiveness of bonding orthodontic attachments to porcelain teeth, composite brackets (Spirit MB) were bonded to 64 porcelain teeth by means of a self-cure non-mixed resin system (Unite). The 64 porcelain teeth were divided into groups of eight and after roughening with a green stone they were subjected to a combination of treatments. Some were etched, some primed with a silane coupling agent and some received both treatments before the brackets were bonded to them. Half of the teeth were then thermally-cycled 500 times between 4 and 60 degrees C before all the brackets were removed in a shear test. The shear data was analysed by one way analysis of variance and the Student-Newman-Keul test. The results showed that the highest bond strength existed in the group which had been both etched and primed but not thermocycled (P < 0.05). The factors that affected the bond strength, beginning with the most significant, were acid etching, primer application, and then thermocycling. A mechanical based composite bracket can offer good bond strength to porcelain teeth. (+info)
Fracture aspects of resin-dentin bonding in non-trimming microtensile test.
(20/389)
Comparative studies on resin-dentin bond strength and failure mode were performed between the conventional tensile test and the microtensile test with non-trimming small specimens, 1 x 1 mm in cross-section, for two brands of dentin bonding systems. The fracture surface of the conventional large specimen showed a catastrophic cohesive failure in dentin at its center and a lesser adhesive failure, suggesting that the whole failure was due to the development of some major cracks. The non-trimming microtensile test showed significantly larger average bond strength with markedly larger standard deviation and significantly larger fraction of adhesive failure than the conventional test. Some small specimens were extremely strong and some were weak according to the heterogeneous distribution of tight bonding and defective or deficient bonding over the whole dentin surface. These results suggest that the non-trimming microtensile test may potentially provide more realistic aspects of resin-dentin bonding than the conventional bulk specimen. (+info)
Efficacy of dentin bonding to cervical defects.
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The bonding efficacy of sclerotic dentin was determined by measuring the polymerization contraction gap width of a commercial light-activated resin composite in a cervical defect and by measuring the micro-Vicker's hardness at the dentin adhesive surface; morphological characteristics were observed using a scanning electron microscope in extracted human incisors and premolars. Contraction gap formation was completely prevented when the cavity wall was primed with 35 vol% glyceryl mono-methacrylate solution after 0.5 mol/L EDTA conditioning. The contraction gap width was significantly decreased when the resin composite was filled into the sclerotic dentin cavity even when priming was omitted. These results suggest that the sclerotic dentin, which is frequently observed in cervical defects, should be preserved as a substrate because it exhibits an effect of dentin priming and is suitable for bonding. (+info)
Porcelain veneer bonding to enamel with plasma-arc light resin curing.
(22/389)
The resin bond strength of plasma-arc curing in restorative dentistry was investigated in comparison to halogen-light curing with respect to two kinds of thickness, shade and opacity of porcelain laminate veneers. The bond strength of the light-cured resin was evaluated by shear tests and SEM observations of the fracture surfaces, and the results were interpreted in terms of the degree of resin polymerization. It was found that plasma-arc curing for 6 s was sufficient to obtain bond strengths similar to those of specimens polymerized with halogen light for 40 s, whereas the plasma-arc curing time needed to be doubled to 12 s in order to achieve similar failure patterns for a darker-shade porcelain of 2 mm thickness. The bond strength achieved by plasma-arc curing was found to be relatively unaffected by the shade or opacity of porcelain. (+info)
Shear bond strength of a new dental adhesive used to bond brackets to unetched enamel.
(23/389)
The aims of the present study were to measure the shear bond strength of a new multipurpose dental adhesive, IntegraCem, for direct bonding of stainless steel and ceramic brackets to unetched enamel, and to determine the mode of bond failure. Both stainless steel and ceramic brackets (GAC) were bonded with IntegraCem to unetched extracted human premolars. After bonding, the teeth were either stored in a water bath at 37 degrees C for 3 days or passed 2500 thermocycles from 6 to 60 degrees C. Debonding was then performed with a shearing force using an Instron universal testing machine. The force was recorded at bond failure. The results showed that the shear bond strength achieved was between 6.7 and 10.8 megapascals (MPa). Bond failure occurred at the enamel-adhesive interface, enabling more efficient enamel clean up. The shear bond strengths measured suggest that IntegraCem adhesive may be effectively used in orthodontic treatment. (+info)
Polymerization with a micro-xenon light of a resin-modified glass ionomer: a shear bond strength study 15 minutes after bonding.
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The purpose of this study was to evaluate the initial shear bond strength (15 minutes after bonding) of a resin-modified glass ionomer (RMGIC, Fuji Ortho LC) cured with two different light-curing units: a conventional visible light (Ortholux XT) and a microxenon light (Aurys). Seventy-five freshly extracted bovine permanent mandibular incisors were randomly assigned to one of five groups; each group consisted of 15 specimens. Group A (Transbond XT) and group B (Fuji Ortho LC) were exposed to the visible light for 20 and 40 seconds, respectively, and used as controls. The remaining three groups (C, D, and E) were bonded with Fuji Ortho LC and cured with Aurys for 10, 5, and 2 seconds, respectively. All samples were tested in a shear mode on an Instron universal testing machine 15 minutes after bonding. The shear bond strength of the control group bonded with Transbond XT was significantly higher (P = 0.000) than those of all the other groups tested. Regarding Fuji Ortho LC, no statistically significant differences were found between the bond strength of the control group cured with Ortholux XT, and those of the groups cured with Aurys for 2, 5, and 10 seconds. The present findings indicate that, compared with visible light-curing, the micro-xenon light enables the clinician to significantly reduce the curing time of RMGICs, without affecting their initial shear bond strengths. (+info)