Comparison of three different preparation methods in the improvement of sealant retention
ABSTRACT The purpose of this in vitro study was to evaluate the effect of three invasive fissure preparation methods in the retention of sealant on the surfaces of permanent molars. One hundred and eight extracted caries-free human molars were used in this study, which were divided into 3 groups according to the fissure preparation: laser, air abrasion and bur. In addition, each of these three groups was further divided into 2 additional groups to isolate those in which a bonding agent would be used from those in which a bonding agent would not be used. After the accomplishment of the different treatments samples from all the 6 experimental groups were submitted to two different bond strength tests: (i) shear bond strength test and (ii) tensile bond strength test. Bond strengths were determined by the dividing fracture load and a statistical test ANOVA was used to evaluate significant differences. The results showed that laser improved the sealant retention when compared with air abrasion preparation when the bonding agent was used. The use of bonding agent increased the sealant retention in all methods except for tensile bond strength when air abrasion was used as the preparation method
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ABSTRACT: The objective of this study was to assess the shear bond strength of resin sealants to saliva-contaminated and noncontaminated enamel, comparing 2 curing protocols: (1) individual light-curing of the intermediate bonding agent layer and the sealant; or (2) simultaneous curing of both materials. Seventy-two enamel test surfaces were obtained from 24 third molars and randomly assigned to 2 groups (N=36): (A) saliva-contaminated; (B) noncontaminated. Each group was divided into 3 subgroups, according to the bonding technique: (1) Prime&Bond and Fluroshield were light cured separately; (2) Prime&Bond and Fluroshield were light cured together; (3) Fluroshield was applied alone. Shear bond strength was tested at a crosshead speed of 0.5 mm/minute. Means (MPa) were: IA-15.61(+/-4.74); IIA-15.71(+/-6.18); IIIA-13.83(+/-1.50); IB-24.73(+/-4.34); IIB-22.41(+/-4.16); IIIB-18.20(+/-3.58). Statistical analysis revealed that overall bond strength to saliva-contaminated enamel was remarkably lower (P < .05) than that recorded under dry conditions. In both contaminated and noncontaminated groups, significantly higher shear bond strength (P < .05) was observed when the bonding agent was applied underneath the sealant. Comparing the curing protocols for contaminated specimens, no statistically significant difference (P > .05) was observed between individual and simultaneous curing. Conversely, for noncontaminated specimens, bond strength was higher and statistically different (P < .05) when the materials were light cured separately. Individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant does not seem to affect bond strength to saliva-contaminated enamel. When dry, noncontaminated conditions are maintained, however, the intermediary and the sealing materials should preferably be light cured separately.Journal of dentistry for children (Chicago, Ill.) 11/2004; 72(1):31-5.
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ABSTRACT: This article provides evidence to support the use of more conservative cavity preparation techniques with adhesive restorative resins. The authors discuss the issue of conservative operative techniques related to hidden or occult caries. The support for contemporary technology also concerns methods of caries detection and the role of magnification, caries risk assessment of the patient, conservative caries management, instrumentation, materials, and techniques.Dental Clinics of North America 11/2005; 49(4):867-87, viii. DOI:10.1016/j.cden.2005.05.005
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ABSTRACT: Purpose: The purposes of the study were to measure the tensile bond strength of composite resin to human enamel specimens that had been either etched or air-abraded, and to compare the quality of the marginal seal, through the assessment of microleakage, of composite resin to human enamel specimens that had been either etched or air-abraded.Materials and Methods: Thirty mandibular molar teeth were decoronated and sectioned mesio-distally to produce six groups, each containing ten specimens that were embedded in acrylic resin using a jig. In each of the four treatment groups, the specimen surfaces were treated by either abrasion with 27 or 50 μm alumina at 4 mm or 20 mm distance, and a composite resin was bonded to the treated surfaces in a standardized manner. In the two control groups the specimens were treated with 15 seconds exposure to 36% phosphoric acid gel and then similarly treated before being stored in sterile water for 1 week. All specimens were then subjected to tensile bond strength testing at either 1 or 5 mm/min crosshead speed. For the microleakage study, the degree of dye penetration was measured 32 times for each treatment group, using a neutral methylene blue dye at the interface between composite and either 27 or 50 μm air-abraded tooth structure or etched enamel surfaces.Results: The mean bond strength values recorded for Group 1 (phosphoric acid etch, 5 mm/min crosshead speed) was 25.4 MPa; Group 2 (phosphoric acid etch, 1 mm/min), 22.2 MPa; Group 3 (27 μm alumina at 4 mm distance), 16.8 MPa; Group 4 (50 μm alumina at 4 mm distance), 16.9 MPa; Group 5 (27 μm alumina at 20 mm distance), 4.2 MPa; and for Group 6 (50 μm alumina at 20 mm distance) 3.4 MPa. An analysis of variance (ANOVA) demonstrated significant differences among the groups, and a multiple comparison test (Tukey) demonstrated that conventionally etched specimens had a greater bond strength than air-abraded specimen groups. No significant difference in dye penetration could be demonstrated among the groups (p= 0.58).Conclusions: Composite resin applied to enamel surfaces prepared using an acid etch procedure exhibited higher bond strengths than those prepared with air abrasion technology. The abrasion particle size did not affect the bond strength produced, but the latter was adversely affected by the distance of the air abrasion nozzle from the enamel surface. The crosshead speed of the bond testing apparatus had no effect on the bond strengths recorded. The marginal seal of composite to prepared enamel was unaffected by the method of enamel preparation.Journal of Prosthodontics 12/2005; 15(1):2 - 8. DOI:10.1111/j.1532-849X.2006.00062.x · 0.91 Impact Factor