Sealing ability of ProRoot MTA and MTA-Angelus simulating a one-step apical barrier technique--an in vitro study

Endodontic treatment of the pulpless tooth with an immature root apex poses a special challenge for the clinician due to lack of an apical stop against which to compact an interim dressing of calcium hydroxide, or the final obturation material. A one-visit apexification protocol with MTA (Mineral Trioxide Aggregate) has be seen as an alternative to the traditional treatment practices with calcium hydroxide [Ca(OH)2]. The aim of this study was to investigate the use of MTA as a 5mm apical barrier by comparing sealing ability of ProRoot MTA to that of MTA-Angelus. 50 freshly extracted Maxillary and Mandibular single canal sound human incisor teeth were used in this study, which were decoronated to standardized 10mm root lengths. The root segments were prepared to simulate the clinical situation of an open apex with Gates Glidden burs # 51 and randomly assigned into 2 experimental groups of 20 samples each (Group A: ProRoot MTA, Group B: MTA-Angelus) and 10 root segments were used as control (Group C) where no apical barrier was used. After obturation the coronal portion of all samples were sealed with Glass Ionomer and stored at 37 degrees C and 100% humidity for 4 weeks. The root segments were then double coated with nail varnish except for the apical 1mm and apical ends of all root segments were suspended vertically in methylene blue dye for 48 hours at room temperature. After removal from the dye, the samples were sectioned longitudinally and linear dye penetration was measured using a Grid and stereomicroscope. The measurements were tabulated and statistically analyzed. The mean percentage of dye leakage for Group A was 55.5% and for Group B was 53.25%. The results showed no statistically significant difference in the sealing ability of ProRoot MTA and MTA-Angelus when used as apical barriers.