Letter to the Editor

Apical leakage continues to be a topic of great interest, due to the fact that clinical failures still occur, despite numerous advances in Endodontics. Most failures are probably attributed to the proliferation of bacteria that remain viable after chemomechanical preparation and cause peri-radicular infection [1]. I read with great interest, the article entitled “Microleakage of Single-Cone Gutta-Percha Obturation Technique in Combination with Different Types of Sealers” by Saeedeh Sadr et al. which has been published in your esteemed journal (IEJ Iranian Endodontic Journal 2015;10(3): 199-203). I want to share few of my thoughts regarding this study. It was a good study comparing the sealing ability of three root canal sealers including AH-26, glass ionomer cement (GIC) and zinc-oxide eugenol (ZOE) in single gutta-percha obturating system using the dye penetration method, but the authors can further redefine the study by incorporating few parameters. First, since the validity of dye leakage studies has been questioned because of the possible effect of entrapped air on ingress of the dye solution [2], dye leakage studies can be conducted under vacuum pressure. Studies have reported that vacuum pressure decreases the volume of entrapped air and allows complete dye penetration [3].