[ in vitro evaluation of coronal microleakage through four temporary restorations by dye penetration]

Temporary restorations should be able to seal the access cavity and prevent bacterial leakage. The aim of this study was to evaluate the amount of dye penetration through temporary restorations, namely Zonalin, Zamharir, IRM and Coltosol, into the root canal. In this experimental study, 120 sound human premolar teeth were selected. After access cavity preparation, cleaning and shaping were accomplished using step-back technique and obturated by lateral condensation technique using gutta-percha and AH-26 sealer. The teeth were divided into six groups [n=20]. In the first to fourth group, the crown was restored with zonalin, zamharir, IRM and coltozol. Group five and six were considered as positive and negative control. After keeping these teeth in 37[degree sign] C and 100% humidity for 48 hours, samples were immersed in 10% Indian ink for 72 hours. After sectioning the crowns longitudinally the amounts of dye penetration in the two halves of teeth were assessed using stereomicroscope [xlO]. Statistical analyses were performed using ANOVA test. Zonalin had minimum and Coltosol had maximum amount of dye penetration. There were not any significant differences between the Zonalin-Zamharir groups and between the IRM- Coltosol groups [p>0.05]. Regarding different materials with ZOE base used in this study to treat tooth root, zonal in is the best as a temporary restorative material. However more comprehensive studies need to be performed about Zamharir

In vitro comparison of apical leakage in root canals obturated with 0.04 and 0.02 tapered gutta-percha

Gutta-percha is the most commonly used material for root canal obturation; it has been recently manufactured with different tapers. The aim of this in vitro study was to compare microleakage of canals obturated with standard gutta-percha [0.02 taper] or the new 0.04 taper gutta-percha master cone using the cold lateral condensation technique. Forty-four extracted single rooted teeth were selected. The crowns were removed and all the canals were prepared using RaCe rotary files. The teeth were then divided into experimental [n=2] and control [n=2] groups. In the first study group, the teeth were obturated with 0.02 taper gutta-percha master cone and lateral condensation. In the second study group, the canals were obturated by 0.04 tapered master cones and the same obturation method. The degree of leakage was measured using fluid filtration method. Data were analyzed statistically by student t-test. There was no significant difference between the mean microleakage of two experimental groups [P=0.558]. Lateral condensation technique using 0.04 tapered master cones can provide an effective apical seal similar to 0.02 gutta-percha cones