Sealing ability of amalgam, super EBA cement, and MTA when used as retrograde filling materials

Abstract

Objective: To compare apical microleakage of MTA following reverse retrograde root filling with that following amalgam and EBA retrofilling.

Design: Prospective random control trial.

Setting: It was conducted at the University of Jordan in 1998.

Materials and methods: The root canals of 79 extracted teeth were instrumented and obturated with vertically condensed gutta-percha. Each tooth was apically resected and the apex was prepared ultrasonically to 3 mm depth and the root surface isolated with nail varnish. Teeth were divided randomly into three groups of 25 teeth each. First group was retrofilled with amalgam, second group with EBA and the third group with MTA. Following immersion in 1% methylene blue dye for 72 hours, the roots were sectioned and the depth of dye penetration was evaluated by a stereomicroscope at x10 magnification.

Interventions: Super EBA is a reinforced zinc oxide cement based on a mixture of 32% eugenol and 68% ethoxy benzoic acid (EBA). MTA is a mineral trioxide aggregate cement (MTA) based on a mixture of sterile water.

Main outcome measures: The sealing effectiveness of the retrograde filling materials used in this study was determined by their ability to inhibit dye penetration.

Results: 56% of the group filled with amalgam and 20% of the group filled with EBA showed dye leakage beyond the retrofilling material whereas the MTA group showed none, two samples from MTA group were eliminated because of their fractured roots. The chi-squared test revealed a statistically significant difference among all three groups (P < 0.05).

Conclusion: MTA cement provides a better seal than amalgam and EBA cement when used as retrograde filling, but the extrapolation of this result into a clinical practice may be questionable.