Purpose Restorative materials and techniques have improved the clinical success of a variety of restorative procedures. Despite these new improvements, microleakage remains one of the leading causes of restoration failure and may lead to postoperative sensitivity, enamel microcracks, marginal staining, discoloration, recurrent caries, and deformation of teeth. This study evaluated microleakages of five recent resin composites in class V cavities. Materials and Methods Standardized class V cavities were prepared on the labial surfaces of one hundred extracted intact and noncarious human permanent premolar teeth. The cavities were divided into five groups (n=20) according to the resin composite material. Groups: A1, A2, A3, A4 and A5 were restored with Omnichroma, Spectrum, Mosaic, Tetric N-Ceram and Harmonize, respectively. The teeth were stained with methylene blue and then sectioned, and the extent of dye penetration was examined under a stereomicroscope and scanning electron microscope (SEM) to evaluate microleakage. One-way ANOVA test was used to statistically analyze the data. Statistical Package for Social Sciences Computer Software (SPSS) version 15.0 was used. Results Dye penetration was observed at the tooth-restoration interface in all the studied samples, with varying degrees of penetration. At the cervical margins of the cavities, no statistically significant difference in the microleakage scores was observed (P=0.16). At the cavity floor, no statistically significant difference in microleakage scores was observed (P=0.74). Omnichroma resin composite had the highest microleakage results. Conclusion Nanohybrid resin composites showed less microleakage than other resin composites. Among all the groups, Omnichroma showed the highest microleakage at the cavity floor and at the cervical areas. Clinical Significance In light of our findings, nanohybrid resin composites appear to be capable of reducing microleakage, and the results reported herein must be verified by additional clinical trials.

AIM: This study was conducted to evaluate the effect of different remineralizing agents on micro-shear bond strength (SBS) of nanohybrid composite resin to dentin. METHODS: Thirty-six human molars were divided into four main equal groups (nine teeth each) according to the type of remineralizing agent used; nanohydroxyapatite, sodium fluoride, fluorohydroxyapatite, and control without remineralizing agent. Each group was divided into three equal subgroups (three teeth each) according to the storage time; 1 day, 1 month, and 3 months. Specially fabricated cylindrical plastic mold was made, and teeth were embedded vertically in the mold to the level of cementoenamel junction of the tooth leaving the occlusal surface projecting above the surface of the mold. Cylindrical fissure carbide bur was used in teeth preparation. Teeth were trimmed perpendicular to the long axes of them. Demineralizing agents (Nano hydroxyapatite, sodium fluoride, and fluorohydroxyapatite) were applied then adhesive system applied then composite resin was applied using five sections of a pediatric intravenous tube to act as molds for composite specimen then the specimens stored in artificial saliva at 37°C for different storage times in an incubator. The micro-SBS was assessed using universal testing machine. Then, the mode of failure for each group was determined using stereomicroscope device. Then, the obtained data were tabulated and statistically analyzed. One-way ANOVA was used to compare between more than two non-related samples. The significance level was set at p ≤ 0.05. Statistical analysis was performed with IBM SPSS Statistics. RESULTS: There was statistically significant difference between the four studied groups regarding bond strength at different storage times. Fluorohydroxyapatite had the highest bond strength mean values followed by nanohydroxyapatite, while the lowest value was the sodium fluoride group. CONCLUSION: Fluorohydroxyapatite and nanohydroxyapatite had a positive effect on micro-SBS to dentin, but sodium fluoride had a negative effect. The storage time increase had a positive effect on the micro-SBS of dentin with fluorohydroxyapatite and nanohydroxyapatite, also it had adverse effect on the dentin bond strength with sodium fluoride and control groups.

IntroductionMicroleakage is one of the important contributing factors in the failure of resin restorations. The aim of this study was to determine the effect of the location of the gingival margin (enamel, dentin, or cementum) on nanohybrid composite resin on the microleakage of Class II posterior restoration.MethodsThis was an in vitro study done at Al-Farabi College of Dentistry and Nursing in Jeddah (Saudi Arabia). Eighty-one previously extracted human molars were taken from clinics at Al-Farabi College and divided into three main groups (27 each) according to the location of the gingival margin. Group 1: the location of the gingival margin was in the enamel. Group 2: at the cemento-enamel junction. Group 3: in the cementum. Each main group was divided into three subgroups (9 each) according to storage time. Subgroup A: storage time was 24 hours. Subgroup B: storage time was one month. Subgroup C: storage time was three months. Class II cavity was prepared in one proximal surface for each molar following the general principles of cavity preparation. All samples were restored by nanohybridresin composite (TetricEvoCeram). The specimens were stored in distilled water at 37°C and a humidity of 100% in an incubator for one day, one month, and three months, respectively, according to the subgroups. After sealing, the samples were stained with 2.5% methylene blue dye. Each sample was examined microscopically by a stereomicroscope using a computerized image analyzing system. Statistical analysis was done by two-way ANOVA test comparing dye penetration mean values (μm).ResultsThe value of dye penetration increased remarkably from enamel, Cemento-enamel junction [CEJ] to cementum, and this was statistically significant (p < 0.001).ConclusionNone of the materials tested was able to completely eliminate marginal microleakage at different gingival margins. The least dye penetration was detected at the enamel gingival margin followed by CEJ and then cementum. The least microleakage was observed at the gingival margin located in the enamel.

AIM: This study evaluated the impact of two remineralizing agents containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and tricalcium phosphate (TCP) on white spot lesions. MATERIALS AND METHODS: A total of 90 freshly extracted upper premolars were divided in three equal groups (30 each): Group A: Control group, Group B: Varnish containing CPP-ACP, and Group C: Varnish containing TCP. The teeth were subjected to Diagnodent test after inducing white spot lesions to assess any surface changes present on the teeth. The readings were repeated post-demineralization and post-remineralization. RESULTS: Statistically significant difference was present in the mean values between the tested groups. CPP-ACP group recorded higher mean value at demineralization when compared to TCP group. Statistically significant difference (p < 0.00`01) was present between the baseline and the demineralization values. CPP-ACP group presented higher remineralization results when compared to TCP group. T-test proved a significant difference between the tested groups. CONCLUSION: CPP-ACP containing varnish had higher remineralizing effect when compared to TCP containing varnish. CLINICAL SIGNIFICANCE: Recently, the focus of restorative dentistry has been directed toward a conservative approach. Prevention and non-restorative treatment of initial enamel caries is the main concern. Remineralization procedures are the most preferred way of regeneration of lost tooth structure.

AIM: This study investigated the effect of different finishing and polishing systems on surface roughness of two types of universal nanohybrid composite resins. MATERIALS AND METHODS: A total number of 40 samples will be prepared to form two main equal groups of specimens (n = 20), according to the composite resin materials. Two universal nanohybrid resin composites were used in this study. First group (A1) is a universal nanohybrid composite resin (Mosaic) and the second group (A2) is a universal nanohybrid composite resin (Harmonize). Each group was subdivided equally into four equal subgroups (n = 5), according to the used finishing and polishing systems. Mold was made to prepare the specimens with a central hole of 4 mm in diameter and 4 mm in thickness. Light curing tip was placed touching the glass slab for 20 s then the cured specimens were removed from the mold and the specimens immediately and immersed in distilled water at 37°C for 24 h. Surface roughness (Ra) was measured using light sectioning vision system. SEM was done to support the results. RESULTS: The results showed that the lowest (Ra) values were recorded by the specimens under Myler strip followed by Polishing Discs treated specimens followed by Diacomp Plus specimens and the highest (Ra) values were recorded by white polishing stone specimens and regardless to finishing or polishing, it was found that mosaic resin composites group recorded statistically significant (p < 0.05) lower roughness mean value than Harmonize resin composites group. p ≤ 0.05 is statistically significant in all tests. CONCLUSION: Achieving long-lasting esthetics in resin composites restorations needs special attention for obtaining optimal resin polymerization and a perfect surface finish using the appropriate finishing and polishing system.

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Background This study evaluated the effect of different bonding techniques on marginal adaptation of Harmonize composite resin at different storage times. Methods Hundred twenty upper premolars were divided into two main groups (n = 60) according to the type of the adhesive system used (self-etch adhesive system or total etch adhesive system). Each group was further divided into three subgroups (20 teeth each) according to the storage times into one day, three months and six months. Standardized Class II cavities were prepared and restored with Harmonize composite incrementally. Teeth were stored in distilled water at room temperature. After each storage time, teeth were sectioned buccolingually into two halves and examined under digital stereomicroscope for the purpose of gap formation detection and scanning electron microscope examination was done to evaluate resin-dentin interfaces. The recorded values were tabulated and statistically analyzed. Regression model using three-way Analysis of Variance (ANOVA) was used for testing significance of the effect of adhesive system, storage period and their interactions on the mean gap area. Tukey’s post-hoc test was used for pair-wise comparisons between the groups when ANOVA test is significant. The significance level was set at P ≤ 0.05. Results Self-etch adhesive system showed statistically significant higher mean gap area than Total-etch adhesive system at the occlusal and cervical margins. Six months period showed the statistically significant highest mean gap area. There was no statistically significant difference between 1 day and 3 months periods; both showed the statistically significant lowest mean gap area values respectively at the occlusal and cervical margins. Conclusions Total-etch adhesive system enhances the marginal adaptation when compared to self-etch adhesive system and the storage period of composite resin in water has adverse effect on the marginal adaptation to all groups with time.

Aim of the study: This study evaluated the impact of two remineralizing agents containing casein phosphopeptideamorphous calcium phosphate (CPPACP), and Tricalcium phosphate (TCP) on white spot lesions. Materials and Methods: A total of ninety freshly extracted upper premolars were divided in three equal groups (30 each). Group A: Control group. Group B: Varnish containing CPP–ACP. Group C: Varnish containing TCP. The teeth were subjected to Diagnodent test after inducing white spot lesions to assess any surface changes present on the teeth. The readings were repeated post demineralization and post-remineralization. Results: Statistically significant difference was present in the mean values between the tested groups. CPP-ACP group recorded higher mean value at demineralization when compared to TCP group. Statistically significant difference (p < 0.0001) was present between the baseline and the demineralization values. CPP-ACP group presented higher remineralization results when compared to TCP group. T-test proved a significant difference between the tested groups. Conclusion: CPP-ACP containing varnish had higher remineralizing effect when compared to TCP containing varnish. Clinical Significance: Recently, the focus of restorative dentistry has been directed toward a conservative approach. Prevention and non-restorative treatment of initial enamel caries is the main concern. Remineralization procedures are the most preferred way of regeneration of lost tooth structure.