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Purpose: This study evaluated in vitro the effect of different filling materials and cleaning agents on the bond strength between glass fiber post/resin cement and primary root dentin in long-term degradation (24h, 6 and 18 months). Methods and Materials: One hundred and twenty roots of bovine primary teeth were endodontically treated and assigned to groups: Control (no material-C); Calen® +zinc oxide (CZO); Vitapex® (V); Calcipex II® (CP). After 7 days, the filling materials were removed using the cleaning protocols: No cleaning (NC); 70% Ethanol (E); Tergenform® (T). Glass fiber posts were luted using resin cement (RelyXTM ARC) after phosphoric acid etching, rinsing, and bonding with an adhesive system (Adper Single Bond 2TM). The specimens were sectioned (±1mm thick) to be tested after 24h, 6 months and 18 months of water storage. The push-out test was performed in universal machine at 0.5mm/min (EMIC DL 500). Data were submitted to three-way ANOVA and Tukey’s test (a=5%). Results: Significant difference was observed for time storage and fillingmaterials (p< .01). Interaction was observed between time storage×filling materials and time storage×filling materials× cleaning agents (p< .05). Bond strength decreased with time storage (24h – 7.10± 3.55; 6m – 5.90± 4.79; 18m – 3.39± 2.87). For all cleaning agents and time storage, the highest bond strength value was observed for CZO (6.38± 4.42) and CP (5.74± 4.30) with significant difference from C (4.16± 3.48). At 24h, CZO/E showed the highest bond strength value (11.27± 3.82), significantly different from C/T (4.04± 3.04), V/NC (5.61± 3.05) and V/E (5.30± 2.13). Concerning 6m, the highest bond strength value was observed for CP/NC (9.86± 6.10) with significant difference from C/E (3.41± 2.79), C/T (3.30± 3.41) and CP/E (4.09± 3.18). At 18m, all groups showed lower bond strength values with no significant difference between them. Conclusion: The long-term degradation decreased the bond strength. The filling materials and time storage influenced the bond strength. |
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