Introduction: Providing adequate coronal seal of temporary filling materials is critical for the success of root canal therapy. The aim of this in vitro study was to compare coronal seal ability of three restorative materials over different periods of time.Materials and Methods: Ninety-eight molar teeth were selected. Once access cavities were prepared, teeth were divided randomly into three time groups (1 day, 1 week, and 4 weeks). Each group was then subdivided into three groups of 10 teeth. Each subgroup was restored using one of three restorative materials including Coltosol, Cavizol and Zonalin and then incubated in distilled water at 37oC. The samples were then immersed in 2% methylene blue dye. After rinsing and drying, teeth were sectioned longitudinally and examined for dye penetration. Kruskal-Wallis and Mann Whitney U tests were used to analyze the data.Results: All experimented materials showed increasing leakage from the 1st day to the 4th week. Zonalin showed more leakage than Coltosol and Cavizol at each time interval (P<0.05), but there was no significant difference between Coltosol and Cavizol.Conclusion: Coltosol and Cavizol are suitable temporary materials for up to 1 week.

Introduction: This in vitro study aims to evaluate the coronal and apical sealing ability of gutta-percha (GP) root filling used with either mineral trioxide aggregate (MTA), new endodontic cement (NEC) or AH26 as filler/sealers.Materials and Methods: Forty eight single-rooted extracted teeth were selected, decoronated and then instrumented. Samples were randomly divided into three experimental (n=12) and two control groups (n=6). In group 1, root canals were filled using lateral condensation technique (L); while single cone technique (S) was used for groups 2 and 3. AH26, MTA and NEC were the root canal sealer/fillers in groups 1, 2 and 3, respectively. Samples were immersed in 1% methylene-blue dye and then independently centrifuged apically and coronally. The roots were split longitudinally and linear extent of dye penetration was measured with a stereomicroscope from apical and coronal directions. Data were analyzed using One-way ANOVA and T-test.Results: No statistical differences in mean apical dye penetration between groups LGP/AH26, SGP/MTA and SGP/NEC were found; SGP/NEC group showed significantly less coronal dye penetration (P<0.001).Conclusion: Considering the limitations of this in vitro study, it was concluded that the simple single cone technique with NEC can provide favorable coronal and apical seal.

Introduction: Coronal microleakage may significantly reduce the prognosis of endodontic treatment. Temporary restorative materials have a crucial role in preventing the infection of root canals between and after endodontic treatment. This in vitro study was designed to evaluate the coronal microleakage of three temporary restorative materials used in endodontics: Coltosol, Cavisol and Cina.Materials and Methods: Seventy-five human premolars and molars were selected for this in vitro study. Access cavities were prepared and amalgam placed on the orifices of canals; the occlusal surfaces were then reduced by 4mm for the temporary restoration. The teeth were divided into three experimental groups of 23 teeth and two control groups of 3 teeth. The access cavities in each group were sealed using one of the test materials and thermal cycling was applied (5-55°C for 150 cycles). Surfaces were then covered with nail polish and wax; the teeth were immersed in 2% methylene blue dye for 7 days. The teeth were rinsed, dried, and sectioned mesiodistally and evaluated under a stereomicroscope for microleakage. Data was analyzed using Kruskal-Wallis and Mann U Whitney tests.Results: The lowest microleakage value was observed in Cavisol and Coltosol groups and the highest in Cina group (P<0.001). There was no statistical difference between Cavisol and Coltosol.Conclusion: Coltosol and Cavisol have appropriate sealing properties as temporary restorations, but the sealing ability of Cina was questionable.

Introduction: The purpose of this in-vitro study was to investigate the influence of the remaining calcium hydroxide (CH) as an intracanal dressing on the apical sealing ability of three endodontic sealers.Materials and Methods: Sixty-six single and straight canals of recently extracted human permanent maxillary central incisors were used. All canals were prepared and sixty of them were randomly divided into two groups with (group 1) and without (group 2) CH medication.Each of these groups was divided into three experimental groups using AH26 (group a), Dorifill (group b), and Apexit (group c). Six remained teeth were divided into positive and negative groups of three each. Root canals were filled with gutta-percha and AH26 (groups 1a, 2a), Dorifill (groups 1b, 2b) and Apexit (groups 1c, 2c) using lateral condensation technique. The apical third of the roots were placed in Pelikan ink for one week. Linear dye penetration was recorded using a stereomicroscope and a digital caliper. Data were compared with analysis of variance (ANOYA).Results: Observed leakage in groups which were filled with Apexit sealer was significantly different (P<0.002). There was no significant difference among groups which were filled with Dorifill and AH26.Conclusion: Calcium hydroxide did not influence the apical sealing ability of AH26 and Dorifill, while it did improve the apical sealing ability of Apexit sealer.

Statement of the Problem: Similar to conventional amalgam, high-copper amalgam alloy may also undergo corrosion, but it takes longer time for the resulting products to reduce microleakage by sealing the micro-gap at the tooth/amalgam interface.Purpose: The aim of this study was to evaluate the effect of self-etch adhesives with different pH levels on the interfacial corrosion behavior of high-copper amalgam restoration and its induction potential for self-sealing ability of the micro-gap in the early hours after setting by means of Electro-Chemical Tests (ECTs).Materials and Method: Thirty cylindrical cavities of 4.5mm x 4.7mm were prepared on intact bicuspids. The samples were divided into five main groups of application of Adhesive Resin (AR)/ liner/ None (No), on the cavity floor. The first main group was left without an AR/ liner (No). In the other main groups, the types of AR/ liner used were I-Bond (IB), Clearfil S3 (S3), Single Bond (SB) and Varnish (V). Each main group (n=6) was divided into two subgroups (n=3) according to the types of the amalgams used, either admixed ANA 2000 (ANA) or spherical Tytin (Tyt). The ECTs, Open Circuit Potential (OCP), and the Linear Polarization Resistance (LPR) for each sample were performed and measured 48 hours after the completion of the samples.Results: The Tyt-No and Tyt-IB samples showed the highest and lowest OCP values espectively. In LPR tests, the Rp values of ANA-V and Tyt-V were the highest (lowest corrosion rate) and contrarily, the ANA-IB and Tyt-IB samples, with the lowest pH levels, represented the lowest Rp values (highest corrosion rates).Conclusion: Some self-etch adhesives may increase interfacial corrosion potential and self-sealing ability of high-copper amalgams.