RESUMO
Objective: Zirconia cores have limited light transmittance and data are scarce on light transmission through zirconia cores with and without the veneering ceramic
Methods: In this in vitro study, Disc-shaped specimens [11.5 mm in diameter and 0.4 [0.05] mm in thickness] were fabricated of three types of zirconia namely Mamut, Heany and ZirkonZahn [n=5]. A disc-shaped specimen [11.5 mm in diameter and 0.65 [0.05] mm in thickness] of veneering ceramic [Cerabien ZR, Kuraray, Noritake, Japan] was also fabricated. The intensity of light transmitted through the zirconia specimens with and without the veneering ceramic was recorded using a light curing unit [LED, SDI Radii Plus, Australia] and its respective radiometer [LED Radiometer, SDI, Australia]. Data were analyzed using repeated measures ANOVA and Tukey's HSD test
Results: A significant difference was noted in light transmission among different types of zirconia before and after veneering. After veneering, light transmission decreased in all specimens and the reduction in light transmission in Zirkonzahn group was significantly greater than that in Heany and Mamut groups [p<0.001]
Conclusion: Veneered zirconia systems have limited translucency and ceramic veneering significantly decreases light transmission through zirconia
RESUMO
By the advancements in root canal filling systems, a new sealer namely Epiphany self-etch sealer [Pentron Clinical Technologies, LLC, Wallingford, CT, USA] was recently introduced to the market that does not require self-etching primer application prior to the use of sealer. On the other hand, dentin surface conditioning with various irrigation solutions can cause chemical and structural dentinal changes. The present study sought to assess the effect of EDTA [final irrigation with distilled water or chlorhexidine] and MTAD on coronal microleakage in root canals filled with Resilon/Epiphany self-etch or AH Plus/Gutta Percha obturation materials. In this ex-vivo study, a total of 140 extracted single rooted human teeth were selected and irrigated with 1.3% sodium hypochlorite during preparation. Samples were divided into 6 test groups and 2 positive and negative control groups. Smear layer was removed by EDTA and final irrigation with distilled water in groups 1 and 4, by EDTA and final irrigation with 2% chlorhexidine in groups 2 and 5 and by MTAD in groups 3 and 6. In groups 1, 2 and 3 canals were filled with AH Plus sealer and Gutta Percha while in groups 4, 5 and 6 canals were filled with Resilon and Epiphany self-etch sealer using lateral condensation method. After placing samples in a split-chamber and sterilizing them, the coronal part of teeth was contaminated with human saliva. Samples were controlled daily for 60 days. Chi square test, survival analysis and log-rank test were used for data analysis. Nine samples [45%] in group 1, 14 samples [70%] in group 2, 18 samples [90%] in group 3, 13 samples [65%] in group 4, 7 samples [35%] in group 5 and 13 samples [65%] in group 6 had microleakage after 60 days. Difference in resistance against microleakage between groups 1 and 3 and also 3 and 5 was statistically significant. MTAD does not have a negative impact on sealing properties of Resilon/Epiphany self-etch sealer but EDTA can be an appropriate dentin conditioner before using AH Plus sealer and Gutta Percha. Also, Chlorhexidine can be a good final irrigant in root canals that are going to be filled with Epiphany self-etch sealer/Resilon