Statement of Problem: Composite reins have recently become popular for posterior teeth restorations.Gap formation and subsequent microleakage are of the complications resulting from such restorations.One of the techniques to overcome polymerization shrinkage of composite resins is sandwich technique (application of GLASS IONOMER as a base beneath the composite resin). Since polymerization patterns in two types of composite resins (LIGHT CURE and self CURE) differ from each other, various effects on the bond strength between GLASS IONOMER and dentin are expected.Purpose: The aim of this in vitro study was to evaluate the effects of self- CURE and LIGHT- CURE composite resins in sandwich technique on the bond strength of LIGHT CURE GLASS IONOMER and dentin.Materials and Methods: 40 extracted human premolars were selected and divided into four groups:Group 1: LIGHT CURE GLASS IONOMER of 1mm thickness was placed on dentin.Group 2: 1mm thickness of LIGHT CURE GLASS IONOMER plus a mass of self CURE composite resin of 2mm thickness were placed.Group 3: 1mm thickness of LIGHT CURE GLASS IONOMER plus LIGHT CURE composite resin as two separate 1mm layer were placed.Group 4: 1mm thickness of LIGHT CURE GLASS IONOMER with 37% phosphoric acid etching followed by two separate layers of LIGHT CURE composite resin of 1mm thickness were placed.SEM was used to determine gap size at GI- dentin and GI- composite interfaces. The findings were analyzed by ANOVA and t-student tests.Results: Groups 1 and 2 showed no gap at GI-dentin interface and also cracks were not observed in all these specimens. In group 3, there was gap between LIGHT CURE GI and LIGHT CURE composite resin and cracks were seen in GI, too. Group 4 showed gap at both interfaces and more cracks were seen in GI. Groups 1 and 2 showed the least gap formation and group 4 showed the most. Statistically significant difference was found between groups 3, 4 and group 1 (control), 2.Conclusion: Base on this study, the application of self-CURE composite resin on LIGHT CURE GI showed no gap and crack formation on GI-dentin and GI-composite interfaces and GI itself. However, LIGHT CURE composite resins and GLASS IONOMER etching aggregated crack and gap formation.

Statement of Problem: Candidiasis is the most common fungal infection in the human oral cavity. 85% of this infection is caused by Candida albicans. Although there is considerable information about the adhesion of Candida albicans to the epithelial cells and prosthetic materials, there are very few studies in regard to the adhesion of Candida albicans to various restorative dental materials.Purpose: This study aimed to compare the adhesion of Candida albicans to three restorative materials, amalgam, LIGHT CURE composite and GLASS IONOMER.Materials and Method: In this experimental study, 54 specimens of amalgam, LIGHT CURE composite and GLASS IONOMER (18 specimens from each group) were transferred to tubes containing suspensions of Candida albicans (1× 106 cell/ml). After 40, 80 and 120 minutes, the specimens of restorative materials were suspended in tubes containing 1ml of saline solution and then 100 microlitre of this suspension were plated in Sabouraud Dextrouse Agar. After 48 hours of incubation, the number of candida colonies was counted. Finally, the data were analyzed using kruskal wallis and Mann-Whitney tests.Results: In the composites and amalgams specimens, the adhesion of Candida albicans increased with time and this difference was statistically significant (p<0.05). In GLASS IONOMER specimens, no statistically significant difference was observed in different periods of time. The highest value of adhesion was related to composite at 120 minutes and the lowest was observed on an amalgam specimens at 40 minutes.Conclusion: The results of this study show that GLASS IONOMER is an appropriate choice as a dental restorative material especially in patients who are susceptible to candidiasis infections.

Background and Aims: Micro leakage is a criterion proposed for assessing the success of any restorative material. Complete seal is difficult especially for dentin margins compared to enamel margins. The aim of this study was to assess the micro leakage at the enamel and dentin margins of class V cavities restored by two GIs and two self-etch adhesive systems.Materials and Methods: This study was done on forty third molars. Class V cavities (3´2´2mm) were prepared on the buccal and lingual surfaces of teeth using high speed handpiece with 0.8 mm diamond fissure burr. The occlusal margins of the cavities in the enamel and gingival margins were placed 1 mm below the CEJ. The teeth were divided into 4 groups and the bondings were CUREd for 20 sec and the teeth were restored. The specimens were kept in distilled water at the temperature of 37°C for 24 hrs. The teeth were thermo cycled and cut in buccolingual direction using diamond disc under water. The dye penetration was evaluated using a stereomicroscope and the leakage was scored. The scores were compared using Kruskal-Wallis test while the paired comparisons were done using Bonferroni correction. P≤0.05 was regarded as significant results.Results: Micro leakage scores were similar at the occlusal and gingival walls of all test groups. At the gingival walls, the least micro leakage scores were observed. “Fuji IX + SE bond” group showed significant differences with the “Fuji IX + G bond” and “Nano GLASS + G bond” groups (P£0.05). At the occlusal walls, the least scores were observed in the “Fuji IX+SE bond” specimens which were significantly different from the other groups (P£0.05).Conclusion: Self-CURE GLASS IONOMERs yielded less micro leakage scores compared to the different types of LIGHT-CUREs due to the less polymerization shrinkage.

Introduction: Cervical root resorption is one of the most important complications of intra coronal bleaching. A way of preventing this type of resorption is using a coronal barrier under the bleaching materials. The aim of this study was to compare the sealing ability of GLASS IONOMER cement and Pro Root Mineral Trioxide Aggregate (MTA) as a coronal barrier in intra coronal bleaching.Materials & Methods: In this study, 40 single-root maxillary anterior teeth were endodontically prepared and divided into two experimental groups (n=15) and two positive and negative control groups (n=5). In the experimental groups, gutta percha was removed up to 3 mm below the cemento enamel junction (CEJ).RMGI and MTA were placed over gutta percha up to the level of CEJ. After a 24-hour incubation period, the bleaching agent (a mixture of sodium perborate and 30% hydrogen peroxide) was placed in the access cavities. The bleaching agents were replaced every 3 days over 9 days. Then, the access cavity was filled with 2% methylene blue for 48 hours. All samples were longitudinally sectioned and the dye penetration range was evaluated using a stereomicroscope. Data were statistically analyzed using Kruskal-Wallis and Mann–Whitney tests (a=0.05).Results: Leakage mean indicated that there was a significant difference between these two groups and leakage was less in ProRoot than GLASS IONOMER.Conclusion: It seems that the MTA can provide a better coronal seal during the bleaching.

Background: Minimally invasive techniques should be employed to maintain pulp vitality without affecting physiological tooth resorption for pediatric patients. This study aims to evaluate clinical and radiographic success of LIGHT CURE calcium silicate and resin‑, modified GLASS IONOMER (RMGI) as indirect pulp‑, capping agent in primary molars in children between 5 and 9 years. Materials and Methods: In this randomized clinical trial study, 40 primary molars with the International Caries Detection and Assessment System criteria 4–, 6 score were divided randomly into two groups after computerized randomization method. After caries excavation by minimally invasive dentistry principle, affected dentin was lined by either LIGHT CURE calcium silicate (Group I) or RMGI (Group II) liner followed by composite restoration. Clinical success was determined with the absence of symptoms and bitewing radiographs were taken at baseline, 3, and 6 months’,interval to measure increase in dentin increment using ImageJ software. Statistical analysis for intergroup comparison was done using Paired t‑, test, and Independent t‑, test was used for intragroup comparison. The level of statistical significance was set at P < 0. 05. Results: Change in dentin increment seen from baseline to 6 months in Group I was 0. 19 mm and in Group II was 0. 20 mm (P = 0. 924). Intragroup increment was statistically significant during all follow‑, up intervals for both the groups (Group I –,P ≤,0. 001, Group II –,P = 0. 009). For baseline remaining dentin thickness >1. 5 mm, statistically significant increase was observed in the dentin increment at 3 months’,interval between both the groups. Conclusion: Both TheraCal LC and Vitrebond show acceptable clinical and radiographic results when used in primary molars as indirect pulp treatment agents. Both the liners are equivalent to each other in terms of feasibility and cost‑, effectiveness but TheraCal LC can be preferred due to better handling and avoiding the manipulation step thereby reducing treatment time.

Background and purpose: In orthodontic brackets, unlike restorative materials or porcelain, the shear bond strength of the adhesives used is important because the oblique forces from food or objects or the tension of the adhesive food affect the brackets. This study aimed at measuring and comparing shear bond strength and adhesive remnant index of LIGHT CURE composite, no mix (self-CURE) composite, and no bond composite (GC Orthoconnect). Materials and methods: A total of 27 non-carious and sound human premolar teeth were used. The samples were divided into three groups, including LIGHT CURE composite, self-CURE composite, and no bond composite (GC Orthoconnect). After bonding and thermocycling process, the metal brackets (American Orthodontics) were then debonded using universal testing machine. Adhesive remnant index (ARI) score was assessed. Results: The highest and lowest SBS mean values were seen in self-CURE group (18. 0402±, 5. 71665) and LIGHT CURE group (7. 7890±, 3. 98995), respectively. There were significant differences in SBS values between all groups except between the no bond group and the self-CURE group (P= 0. 18, P>0. 05). The highest ARI scores were 0 in the self-CURE group and 3 in the no bond group and the LIGHT CURE group. Conclusion: The no bond composite provided acceptable overall shear bond strength and compared to LIGHT CURE composite showed higher shear bond strength and lower bond failure.

Background and Aim: Nonmetallic tooth- colored posts adhere to canal walls by dentin bonding agents and resin cements. Better retention and proper distribution of stress result from enough and proper bonding. The purpose of this study was to evaluate bond strength of D.T. LIGHT - post with two different resin cements (selfCURE & dual-CURE) and to investigate the effect of irrigating solutions applied in root canal on bond strength of the resin cements and D.T.LIGHT- post to root canal wall.Materials and Methods: In this experimental study 40 single root teeth (maxillary canine & central) were selected and stored in 0.1% thymol solution for one week and transferred to distilled water. The teeth were decoronated 2mm above CEJ. The canal space was mechanically enlarged using k-files (up to # 70). The teeth were randomly divided into two groups. The first group was irrigated with 2.6% NaOCl, and the second was irrigated with normal saline. After drying, the teeth were filled with gutta percha cones using lateral condensing method. After two weeks the post space was prepared and D.T.LIGHT- post was inserted in each subgroup using self or dual-CURE cements according to manufacturer's instructions. After thermocycling, the apical part was cut 1cm below CEJ. The remained length was divided into 9 equal sequential sections. Each section was submitted to shear push-out test in universal testing machine. Statistical analysis of the bond strength data was performed using ANOVA and post hoc tests with p<0.05 as the level of significance. All failed specimens were examined under stereomicroscope. Degrees of conversion (DC) of the cements were determined by FTIR.Results: Significant difference in bond strength values were found among sites (P=0.001) and cements (P=0.03). With increasing in depth, bond strength decreased. The mean bond strength value in dual-CURE resin cement was higher than self-CURE cement. The irrigating solutions caused no significant difference in bond strength (P=0.46). DC% had significant difference in various depths.Conclusion: According to the results of this investigation, bond strength of dual-CURE cement is higher than self-CURE one in D.T LIGHT- post because of post's translucency. 2.6% sodium hypochlorite does not affect the bond strength.

Introduction: The purpose of this in vitro study was to compare the microleakge rate of class V compoGLASS-F and Fuji II LC restorations.Materials & Methods: Sixty class V cavity preparations with occlusal margins in enamel and gingival margins in cementum were prepared on the buccal and lingual surfaces of 30 extracted human premolar teeth. The teeth were divided randomly into 2 treatment groups. Group 1 was restored with Fuji II LC and group 2 with compoGLASS-F. After treatment, the samples were stored in tap water for 24 hours, then thermocycled, stained with dye, and finally scored for microleakge. The Mann-Whitney analysis of variance was done for data analysis (a=0.05). Results: The Fuji II LC had a higher degree of microleakge in occlusal and occlusal plus axial walls compared with compoGLASS (P=0.000). Where as, compoGLASS had microleakag in gingival and gingival plus axial walls (P=0.0003).Conclusion: The results revealed that Fuji II LC had less microleakage in the gingival margin in which enamel does not exist. Where as microleakage of compoGLASS restorations was significantly less than Fuji II LC in the occlusal wall where enamel exists.