ABSTRACT
Introduction and objective: GuttaFlow2 is a further development of the silicone sealer GuttaFlow, exhibiting a stiffer consistency. This is intended to overcome possible problems regarding retention of the apical part of the root canal filling when preparing for a fiber post. GuttaFlow2 is delivered within a capsule, like GuttaFlow, or within an automix syringe. This study compared apical dye leakage of GuttaFlow2 in comparison to GuttaFlow and AH Plus. The null hypothesis tested was that different sealers exhibited similar microleakage. Material and methods: Seventy extracted human lower premolars with fully mature apices were root canal prepared to 45/.04 and divided into seven groups: group 1: AH Plus sealer, group 2: "normal" setting GuttaFlow, group 3: "fast" setting GuttaFlow, group 4: GuttaFlow2 within a capsule, group 5: GuttaFlow2 within an automix syringe, group 6: positive control, group 7: negative control (n = 10 each). Root canals were filled with sealer (except group 7) and a master gutta-percha cone size 40/.04 using the non-compaction technique. A dye penetration test was carried out by centrifugation for 3 min at 30 G within 5 % methylene blue dye. Linear dye penetration was recorded. Statistical evaluation was carried out with IBM SPSS 19.0 (α = 0.05). Results: The positive control was significantly different from all other groups (ANOVA, p < 0.001; Student-Newman-Keuls post-hoc test p < 0.05). When the control groups were disregarded, no significant differences were apparent. Groups 1 to 5 showed low leakage values when compared with results of earlier studies using a similar methodology. Conclusion: All sealers tested exhibited low dye leakage values.
ABSTRACT
Introduction and objective: Self-adhesive resin cements are applied in only one clinical step whose technique is considered less sensitive and of easy handling. However, there is some concern relating to a reliable and effective bonding to tooth structure, particularly when dentin is involved. The aim of this study was to evaluate microtensile bond strength of self-adhesive resin cements to deep dentin as well as to discuss some concepts involving these materials. Material and methods: Twenty-eight freshly extracted third molars were used. Their crowns were sectioned using a diamond disc (Isomet) to obtain occlusal deep dentin flat surfaces. The teeth were randomly assigned to four groups (n = 7): RelyX ARC/3M ESPE conventional resin cement (Group 1), and three self-adhesive resin cements - RelyX U100/3M ESPE (Group 2), Set/SDI (Group 3) and Maxcem/Kerr (Group 4). The products were applied according to the manufacturer's instructions. Tetric EvoCeram (Ivoclar Vivadent) blocks were used to simulate indirect restorations that were cemented onto the dentin surfaces. These blocks were sandblasted with oxide aluminum before adhesive procedures. The samples were stored in distilled water at 37±2°C for one week. Following, the samples were prepared for microtensile bond strength tests, which were performed at a crosshead speed of 1.0 mm/min until failure. Tensile bond strength data were calculated and the results were statistically analyzed by two-way ANOVA and Tukey test (p < 0.05). Results: The means (SD) (in MPa) were - Group 1: 14.7a (5.7); Group 2: 7.5b (2.3); Group 3: 5.6b (2.1); and Group 4: 4.7b (1.4). ANOVA showed significant differences and Tukey test identified differences among groups. Group 1 showed the highest bond strength mean. Bond strength mean of the other self-adhesive resin cements to dentin did not show statistical difference among them. Conclusion: Self-adhesive resin cements showed lower bond strength to dentin than RelyX ARC conventional resin cement. The highest bond strength mean of RelyX ARC is related to its mechanism of action. However, the mechanism of action involved in self-adhesive resin cements seems to be effective for clinical use if a proper prosthetic dental preparation is observed.
ABSTRACT
Objective: This study evaluated sealing properties of root canal fillings with an additional composite barrier. The null hypothesis tested was that different sealers and different methods of sealer removal did not influence microleakage. Material and methods: Eighty extracted human molars with fully mature apices had root canal prepared to size 60 taper .02 and divided into eight groups: three experimental groups for each sealer and negative/positive control (n = 10 each). Teeth of experimental groups were mounted into the molar region of a training puppet to simulate clinical conditions. Root canals were filled with AH Plus or GuttaFlow and gutta-percha. Excess sealer was removed with: ethanol-moistened foam pellet only, additional preparation with a water-cooled diamond bur or additional etch-and-rinse procedure (37% phosphoric acid gel). All procedures were carried out until clean as judged by the naked eye. In all groups except the positive control Syntac was applied to the access cavity. Tetric flow was applied in two increments of 1 mm each. A dye penetration test was carried out by centrifugation for 3 min at 30 G within 5% methylene blue dye. Statistical evaluation was carried out with PASW 18.0 (α = 0.05). Results: Although the two sealers had different chemical composition, sealer exhibited no influence on the results, whereas technique of sealer removal did (Two-way-ANOVA, p < 0.001). Groups with "foam pellet" or "bur preparation" showed significantly more leakage than groups with "etch-and rinse" (SNK, p < 0.05). Conclusion: Applying an etch-and-rinse procedure prior to Syntac may be beneficial for the adhesive seal over root canal fillings.
ABSTRACT
Introduction: The purpose of this study was to test different sealerremoval protocols following root canal filling before adhesive seal ofaccess cavities. Material and methods: Forty single root teeth wereselected for the study, prepared to size 60 taper .02, and filled withAH plus and a single gutta-percha cone size 55 taper .02. Excesssealer was removed with: ethanol-moisturised foam pellet (group 1),pellet and additional etch-and-rinse procedure (group 2), pellet andadditional preparation with a water-cooled diamond bur (group 3) orby etch-and-rinse following temporary filling for one week (group 4).Syntac and Tetric flow were used as a secondary protective seal. Adye penetration test (centrifugation 3min / 30G; 5% methylene blue)was carried out. Results were analyzed statistically using PASW 18.0(Kolmogorov-Smirnov-test, Kruskal-Wallis-test, Mann-Whitney-test;p < 0.05). Results: Groups 2, 3 and 4 revealed less leakage than group 1(p < 0.05; Mann-Whitney-tests) and displayed no coloration exceedingthe adhesive seal. Teeth with immediate (group 2) or delayed (group4) adhesive seal showed similar results. Conclusion: Acid etching orbur preparation may be recommended before adhesively sealing theaccess cavity in single-rooted teeth. There is no need to wait until thesealer has set.