Background Currently, the demands for restorations have increased considerably; thus, improvements and modifications have been made in dental composite technologies especially using materials that have been claimed to improve color stability. Objective This study aimed to determine the effect of various solutions on the color stability of different restorative materials in vitro study. Methods This study used three types of esthetic restorative materials. The samples comprised 45 discs, including 15 micro-hybrids, 15 nano-hybrids, and 15 glass ionomers). These discs were immersed in various beverages an hour a day for one month at room temperature. The color stability was measured using a spectrophotometer before/after immersion (days 7 and 30). Results We realized a significant difference in color change with Coca-Cola and tea-milk solution after seven days and 30 days (p < 0.05). However, no significant difference was found in the samples immersed in DM after seven days and 30 days (p > 0.05). The highest value of lightness (∆L) and stainability (∆a) was seen in micro-hybrid after 30 days of immersion in tea-milk solution (− 12.16 ± 1.74 and 11.4 ± 3.82, respectively), while most samples had a positive ∆b value. Conclusion After one month, the tea-milk solution affected the color stability of all used restorative materials. In addition, micro-hybrid had higher color stability than nano-hybrid and glass ionomer.

Background A thorough understanding of the original root and canal anatomy is a critical technical prerequisite for performing cleaning and shaping treatments. Therefore, this research aimed to characterize maxillary first premolar teeth' root morphology and canal architecture. Methods One hundred forty-two extracted human adult maxillary first premolar teeth have been retrieved. The extracted teeth were thoroughly cleaned and irrigated to eliminate any remaining debris or blood. They were then preserved in formalin solution until they were eligible for screening. To begin, a visual examination was employed to ascertain the number of roots and their geometry in each sample. Then, utilizing digital radiography in two plains, mesiodistal and distomesial, to further determine those parameters. Finally, a sectioning technique had been used to have the samples cut mesiodistally into slices to validate the internal root canal architecture and identify the number of root canals and their varieties in accordance with Vertucci's categorization system. The canal layout, the pulp chamber, and the root canals were all highlighted (marked) using a fine tip marker in a permanent orange hue to make the canal features more accessible and accurate to visualize. All of the processes were conducted by two highly qualified dentists. The sample size was estimated statistically using the Sealed Envelope program, and the percentage of each configuration was derived in proportion to the overall sample size in order to establish the percentage of each type in each configuration. Results From the 142 teeth examined, 42 (29.57%) had one root, 97 (68.31%) had two roots, and only three premolars (2.12%) had three roots. Concerning canal configurations, 100 teeth (70.43%) had type (IV) canal configuration, followed by 37 teeth (26.05%) had types (V), three teeth (2.12%) had type (VIII), and one tooth (0.70%) for each of type (I) and type (II). Conclusions The anatomical pattern of inspected maxillary first premolars are mainly two rooted and predominantly have a type (IV) canal morphology.

Background Currently, the demands for restorations have increased considerably; thus, improvements and modifications have been made in dental composite technologies especially using materials that have claimed to improve color stability. Objective This study aimed to determine the effect of restorative materials on dental color stability in vitro using various solutions. Methods In this study, the study samples were composed of 45 discs from different restorative materials (15 micro-hybrids, 15 nano-hybrids, and 15 glass ionomers). These discs were immersed in various beverages an hour a day for one month at room temperature. The color stability was measured using a spectrophotometer before/after immersion (days 7 and 30). Results We realized a significant difference in color change with Coca-Cola and tea after 7 days and 30 days (p < 0.05). However, no significant difference in the samples immersed in DM after seven days and 30 days (p > 0.05) was found. The highest value of lightness (∆L), and stainability (∆a) was seen in micro-hybrid after 30 days of immersion in tea solution (-12.16 ± 1.74 and 11.4 ± 3.82, respectively), while most samples had a positive ∆b value. Conclusion The black-tea affected the color stability of all used restorative materials after one month. In addition, micro-hybrid had higher color stability than nano-hybrid and glass ionomer.

Background Potential liner materials include resin modified glass ionomer (RMGI) and flowable liners have been suggested by some studies to inhibit the occlusal and gingival microleakage in Class II composite restorations, which may act as a flexible intermediate layer, relieving the stresses of polymerization shrinkage and subsequently decreasing the microleakage. Objectives The purpose of this study is to determine the microleakage prevention effect of two different liners (Resin- modified glass ionomer and Flowable composite liner) on the occlusal and gingival cavosurface margin of deep class II cavity restorations using glass-ceramic microhybrid composite. Materials and Methods Class II cavities were made on both mesial and distal proximal sides of twenty three extracted permanent molars (n= 45 cavities); the gingival margins were placed (1 mm) apical to the cemento enamel junction, and they were randomly assigned to three groups (n=15 cavities). All the cavities were filled with microhybrid resin composite using centripetal placement technique. In group A, no liner was used under the composite, in group B, RMGI liner was used and in group C, flowable liner was used. The specimens were kept in distilled water for 1 week and then they were thermocycled. In order to evaluate the marginal microleakage, the teeth surfaces were isolated with nail varnish then immersed in a 2% methylene blue dye for 24 hours. The specimens were then carefully sectioned mesially/distally at the center and were studied under a stereomicroscope. Then scoring was done. Results The results of this study show that in all of the groups the microleakage at the gingival margin was more than at the occlusal margin; in group A (p < 0.01), and in group B and C (p > 0.05). At the occlusal margin, group A showed higher microleakage than group B (p < 0.01), and group C (p > 0.05). At the gingival margin, group A also showed higher microleakage than group B and C (p < 0.01). At the occlusal and gingival margins, group B showed less microleakage than group C (p > 0.05). Conclusion The microleakage at the gingival margin was higher than at the occlusal margin in deep class II microhybrid resin composite restorations. More microleakage was seen in the group in which no liner was used. Therefore, it is imperative to use liner under microhybrid composite in deep class II cavity restorations. Resin Modified glass ionomer liner has the ability to reduce occlusal and gingival microleakage more than flowable liner but statistically the difference was not significant. None of the tested liners were able to prevent occlusal and gingival microleakage completely.