Micro leakage of composite resin restorations following contamination with primary teeth root canal filling materials: an in vitro study

The aim of this in vitro study was to assess the microleakage of composite restorations following contamination of access cavity with root canal filling materials of primary teeth.

Forty primary canines were selected for this study. Standardized access cavity on the lingual surface of the canine was prepared. The margins of preparation were ended on enamel. The teeth were randomly assigned into 4 groups (10 teeth/group). Teeth in group 1 served as a control, no material applied. For the other 3 groups the access cavity was filled with one of the following root canal filling material: Zinc Oxide and Eugenol (ZOE), calcium hydroxide (Ca(OH)2) and Vitapex. The root canal filling paste was left for two minutes in the cavity then washed out. The access cavity then restored with composite resin. After thermocycling for 500 cycles, teeth were immersed in 1% methylene blue for 24 hours, and then sectioned longitudinally in bucco lingual direction. The microleakage evaluation was carried under stereo-microscope and the worst result for each section was recorded. The data were statistically analyzed using Kruskal-Wallis and Post Hoc tests.

All samples in the ZOE group showed leakage. However, the control, Ca(OH)2 and Vitapex groups showed leakage in 30%, 40% and 50% of the tested samples respectively. Microleakage occurred more significantly in ZOE group in comparison to the other test groups (p=0.00). Nevertheless, there was no significant difference in microleakage between the control group, Ca(OH)2 and Vitapex groups.

Contamination of the access cavity with primary teeth root canal filling materials showed different levels of leakage in composite resin restoration and the ZOE group showed the highest microleakage scores.