Microleakage of Amalgam Restorations after Exposure to Electromagnetic Fields of a Commercial Hair Dryer: An Ex-Vivo Study.

Background: Dental amalgam is a popular restorative material used in posterior teeth. Hair dryers can emit electromagnetic fields (EMFs) that may affect the microleakage of the amalgam-tooth interface.

Objective: The aim of this experimental study was to investigate whether the EMFs produced by commercial hair dryers could cause microleakage in amalgam restorations.

Material and methods: In this experimental study, a total of 100 human extracted teeth without cavities were selected and prepared for class V preparations on their buccal aspects. The teeth were divided into five groups (G1-G5), each containing 20 teeth. Group 1 served as the control group and was not subjected to any treatment. Groups 2 to 5 were exposed to EMFs of a hair dryer (2000 W, 220 V, and 50 Hz). Groups 2 and 3 were exposed to "EMFs +Hot Air" for 20 min at 10 cm and 30 min at 5 cm, respectively. Groups 4 and 5 were exposed to "EMFs +Cool Air" for 20 min at 10 cm and 30 min at 5cm, respectively. After preparation, the sectioned teeth were evaluated for microleakage using dye penetration measurement.

Results: The microleakage scores showed a significant difference among the three exposure groups (G2, G3, and G5) and the control group (P=0.001, 0.002, and 0.01, respectively). However, there was no significant difference between G4 and G1. The microleakage score in G2 was higher than that in G4.

Conclusion: This study suggests that the common use of hair dryers can lead to damage in amalgam restorations.