The objective of this study was to investigate the effect of operator variability on the marginal performance of resin composite restorations bonded with an acetone-base one-bottle adhesive in standardized dentin preparations.
Five general practitioners were recruited for this trial. In the first group, each dentist received six extracted human teeth with dentin preparations (Ø 3.5 mm, 1.5 mm deep), cut in flatground proximal dentin, and original packages of Gluma One Bond adhesive and Charisma resin composite (Heraeus-Kulzer, Werheim, Germany) including instructions for use. For the second group, the operators were orally instructed, emphasizing the importance of the moist technique, before they received another six teeth for restoration with the same materials. Finally, a third group of six preparations was restored in order to evaluate a possible training effect. The restored teeth were stored in a hygrophor prior to removal of excess material and microscopic determination of the maximum marginal gap width (MGW). Statistical analyses were performed with the Kruskal-Wallis and Wilcoxon tests at p < 0.05.
Apart from two samples, preparation margins in the first test group showed gaps between 1 and 12 microns. In the second and third groups, 15 and 16 restorations were gap free, respectively. Significant interoperator variation was found in the first group only. Marginal performance of group 1 restorations was significantly inferior to groups 2 and 3, which were not different (p = 0.79).
Application of the one-bottle adhesive is technique-sensitive and requires meticulous attention to the instructions.
"In the second part of the present study, rigorous instructions on the use of the different tested adhesive systems were delivered to the participants before they were asked to perform the three adhesive restorations on the lingual side of each tooth. Our results showed no statistical difference in mean microleakage score between before and after delivery of the instructions, which is in disagreement with the findings of Finger and Balkenhol . Therefore, following the manufacturer's instructions in using adhesive systems is very important for the success of adhesive restorations, but it is not the only important factor: other parameters include the distance between the tip of the air syringe and the surface of the cavity, orientation of the tip, and the air pressure of the syringe. "
[Show abstract][Hide abstract] ABSTRACT: Objectives. The aim of this study was to evaluate the influence of operator skill on microleakage in class V composite restorations. Materials and Methods. A total of 16 dentists and 25 dental students were enrolled, and 123 extracted teeth were allocated according to the adhesive being tested: Scotchbond Multipurpose, Adper Scotchbond 1 XT, and AdheSE. Each operator was asked to restore one tooth from each experimental group: two class V cavities were cut on each tooth and each adhesive was used on the same tooth before and after instructions for its use. After filling cavities with composite (Z100), the teeth were thermocycled. Results. For all of the tested adhesives, the mean microleakage score was lower for the dentists than for the students. The mean scores for the three tested adhesives were statistically similar before and after instructions for use. Conclusion. Our results indicate that the skill of the operator has a significant influence on microleakage.
"The moisture dependence of dentin is related to the type of solvent in the adhesives chemical formulations. Ethanol-based adhesive systems seem less sensitive to the amount of moisture in dentin (Jacobsen & Söderholm, 1998; Finger & Balkenhol, 1999; Reis & others, 2003). "
[Show abstract][Hide abstract] ABSTRACT: This study evaluated the effect of organic solvent (acetone or ethanol) on the microtensile bond strengths (MTBS) of an adhesive system applied to dry and moist dentin. Sixteen extracted human third molars were ground to expose a flat occlusal dentin surface and acid etched for 20 seconds (20% phosphoric acid gel, Gluma Etch 20 Gel, Heraeus/Kulzer). After rinsing the acid etchant, an ethanol-based one-bottle adhesive system was applied to the mesial half of the occlusal dentin surface. An acetone-based, one-bottle adhesive system was applied to the distal half of the ground dentin surface. The teeth were randomly assigned to groups. In Group 1, the etched dentin was thoroughly air dried and an ethanol-based one-bottle adhesive system was applied (Gluma Comfort Bond, Heraeus/Kulzer) (GCB). In Group 2, the etched dentin was thoroughly air dried and an acetone-based one-bottle adhesive system was applied (Gluma One Bond, Heraeus/Kulzer)(GOB). In Group 3, excess moisture was removed after acid etching, leaving a moist dentin surface and a one-bottle ethanol-based adhesive was applied (Gluma Comfort Bond). In Group 4, excess moisture was removed after acid etching, leaving a moist dentin surface and an acetone-based adhesive was applied (Gluma One Bond). A hybrid resin composite (Venus, Heraeus/Kulzer) was applied to the bonded surface in four 1-mm increments and light cured according to manufacturer's directions. The specimens were then sectioned with a slow-speed diamond saw in two perpendicular directions to obtain sticks with a cross-section of 0.5 +/- 0.05 mm2. The microtensile bond strength (MTBS) test was performed with a Bencor device in an Instron machine at a crosshead speed of 0.5 mm/minute. The data were subjected to a two-way ANOVA and Scheffé Post hoc test (p < 0.05). The experimental MTBS measured for dry dentin were Group 1 = 37.0 +/- 10.6 and Group 2 = 34.7 +/- 9.0 in MPa (mean +/- SD); and on moist dentin, Group 3 = 50.7 +/- 11.0 and Group 4 = 38.5 +/- 10.5 in MPa (mean +/- SD). The ethanol based adhesives resulted in higher MTBS than acetone-based adhesive (p < 0.008) and bonding to moist dentin resulted in higher MTBS (p < 0.001). GCB applied on moist dentin resulted in statistically higher bond strengths than the other groups. The highest MTBS were achieved with the use of an ethanol-based adhesive to moist dentin.
"(Koliniotou-Koubia et al. 14 , 2001). In spite of its inherent toxicity, the aggressive potential of acetone is controversial due to its high and fast volatilization (Finger, Balkenhol 8 , 1999). The results of the study by Ivanyi et al. 12 (2002) suggest that dental bond materials applied on a very thin layer of dentin may affect the blood supply to the dental pulp. "
[Show abstract][Hide abstract] ABSTRACT: The vascular changes in the subcutaneous connective tissue of rats induced by dentin bonding systems (one step) was studied and compared to those induced by saline solution (negative control) and Furacin (positive control), during the exudative phase of the inflammatory process. Twenty mg/kg of Evan's blue were injected intravenously in the vein of the rats' penises; 0.1 ml of each substance tested was inoculated in the subcutaneous tissue. After a 3 hour period the animals were sacrificed and their skins were excised and punched out with a standard steel 2.5 cm in diameter. The specimens were immediately immersed in 8 ml of formamide and taken to a double boiler for 72 hours at 37 C, to remove the dye. The liquid containing the overflowed dye was filtered, analyzed in the spectrophotometer (620 nm) and classified according to the criteria established by Nagem-Filho, Pereira (1976). After statistical analysis, the irritative potential of the substances was ranked as follows: Furacin (severe) > Single Bond and Bond 1 (moderate - no significant differences between the dentin bonding systems tested) > saline solution (not significant as regards the irritation degree).
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