RESUMEN
BACKGROUND: This study aimed to compare the effect of four temporary luting agents on preventing the coronal microleakage of teeth restored with custom cast post and core. MATERIALS AND METHODS: In this in vitro original study, after removing 9 mm of gutta percha from root canals of 32 single-canaled premolars, the acrylic resin patterns of the post and core were fabricated. Patterns were cast with Ni-Cr metal alloy and then cemented with glass ionomer. Using self-curing acrylic resin, provisional restorations were made. Then, teeth were randomly allocated to four groups for each temporary cement including zinc oxide eugenol (Temp Bond), zinc oxide noneugenol (Temp Bond NE), noneugenol resin-based temporary luting agent (Temp Bond Clear), and noneugenol urethane methacrylate polymer-based temporary luting agent (Dento temp). Teeth were subjected to thermocycling, immersed in silver nitrate for 6 h and then sectioned. The amount of dye penetration in the margin of provisional crown and into the coronal part of the root canals was measured using a stereomicroscope. Data were analyzed using the Kruskal-Wallis and Dunn tests with significance level of 0.05. RESULTS: All the luting agents showed some degree of microleakage (Group 1 showed the most microleakage). According to the pair comparison between the groups, Group 1 revealed a significant difference with others (P < 0.05). Furthermore, Group 2 showed more microleakage as compared to Group 4 (P = 0.037). CONCLUSION: Temp Bond showed the highest microleakage as compared to other luting agents. Furthermore, Temp Bond NE revealed a weaker sealability as compared to Dento temp.
RESUMEN
PURPOSE: The apical seal provided by a root canal filling may be breached via coronal leakage. This study aimed to compare the teeth restored with custom-made cast metal posts and cores cemented with different luting agents in terms of coronal microleakage after thermocycling. MATERIALS AND METHODS: This in vitro study was conducted on 32 extracted single-canal teeth. Root canals were prepared by step-back technique and filled with gutta percha and sealer. The coronal 7 mm of gutta percha was removed, and post space was prepared using peeso reamers #2 and #3 consecutively. After fabricating the acrylic resin patterns of the posts and cores, they were cast using Ni-Cr metal alloy. The specimens were divided into 4 groups in which the castings were cemented using one of the following luting agents: zinc phosphate (ZP), glass ionomer (GI), Panavia F 2.0, and Speed CEM. After cementation, the teeth were immersed in distilled water and incubated for 7 days. Then, the teeth were subjected to thermocycling, immersed in silver nitrate for 6 hours, and finally sectioned. The degree of dye penetration into the coronal part of the specimens was measured using a stereomicroscope. Data were analyzed using Kruskal-Wallis and Mann-Whitey U tests with significance level of 0.05. RESULTS: The median microleakage in ZP, Speed CEM, GI, and Panavia were 171.89, 114.76, 26.51, and 20.02 µm, respectively. Pairwise comparisons among GI and ZP, GI, and Speed CEM, ZP and Panavia, ZP and Speed CEM, and Panavia and Speed CEM groups yielded significant differences (p < 0.05). CONCLUSION: Complete coronal seal was not achieved with any of the luting agents. The highest and the lowest degree of microleakage was yielded by ZP and Panavia luting agents, respectively.
