Aim: The aim of this study was to in vitro evaluate the apical sealability of mineral trioxide aggregate (MTA) when used as an orthograde root filling material, and to evaluate whether smear layer removal has any influence on the apical seal of this material.
Materials and methods: Forty single-rooted human mandibular premolars were selected in this in vitro study. The selected teeth were randomly divided into two equal groups (n = 20) based on the irrigation type. Group 1 was irrigated using distilled water to keep the smear layer intact, and group 2 was irrigated using NaOCl 5.25% and ethylenediaminetetraacetic acid (EDTA) 17% to remove the smear layer. All teeth were instrumented using a step-back technique and obturated using white MTA. Microleakage of 0.2% rhodamine B solution at the tooth-material interface was evaluated to assess the apical seal of MTA. The data were analyzed statistically using Mann-Whitney test U-test (p = 0.05).
Results: When the smear layer was present, MTA revealed less leakage compared to the group of MTA without smear layer with statistically significant difference (p <0.05).
Conclusion: The apical seal produced by MTA when smear layer is left intact was better than the apical seal of MTA when smear layer is removed.It can be stated that MTA is a promising root canal filling material with good sealing ability in the presence of a smear layer.
Clinical significance: Using white MTA material for the obturation of root canals is a useful procedure. It could be done without complexity in irrigation during root canal treatment and cause no discoloration to the teeth.
Keywords: Microleakage; Mineral trioxide aggregate; Obturation Smear layer..