Objective The aim of this review was to provide an insight about the factors affecting the properties of glass ionomer cements and provides a review regarding studies that are related to modification of glass ionomer cements to improve their properties, particularly on physical‐mechanical and antimicrobial activity. Methods PubMed and Science Direct were searched for papers published between the years 1974 and 2018. The search was restricted to articles written in English related to modification of glass ionomer cements. Only articles published in peer‐reviewed journals were included. The search included literature reviews, in vitro, and in vivo studies. Articles written in other languages, without available abstracts and those related to other field were excluded. About 198 peer‐review articles in the English language were reviewed. Conclusion Based on the finding, most of the modification has improved physical‐mechanical properties of glass ionomer cements. Recently, researchers have attempted to improve their antimicrobial properties. However, the attempts were reported to compromise the physical‐mechanical properties of modified glass ionomer cements. Clinical significance As the modification of glass ionomer cement with different material improved the physical‐mechanical and antimicrobial properties, it could be used as restorative material for wider application in dentistry.

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Objectives This study aimed to compare the polymerization shrinkage and degree of conversion of new zirconia-reinforced rice husk nanohybrid composite with commercialized microhybrid and nanofilled composites. Materials and Methods Overall, 180 samples were used for polymerization shrinkage (buoyancy and optical methods) and degree of conversion tests in which they were divided into Group 1, nanofilled composite (Filtek-Z350- XT; 3M ESPE, St Paul, MN 55144-1000, USA), Group 2, microhybrid composite (Zmack-Comp), and Group 3, nanohybrid composite (Zr-Hybrid). Polymerization shrinkage test was performed using buoyancy and optical methods. For buoyancy method, samples were weighed in air and water to calculate the shrinkage value, whereas, for optical method, images of nonpolymerized samples were captured under a digital microscope and recaptured again after light-cured to calculate the percentage of shrinkage. Degree of conversion was tested using Fourier-transform infrared spectroscopy spectrometer. Statistical Analysis Data were analyzed using one-way analysis of variance complemented by post hoc Dunnett’s T3 test for polymerization shrinkage and Tukey’s honestly significant difference test for degree of conversion. Level of significance was set at p < 0.05. Results Group 3 demonstrated similar polymerization shrinkage with Group 1, but lower shrinkage (p < 0.05) than Group 2 based on buoyancy method. However, optical method (p < 0.05) showed that Group 3 had the lowest shrinkage, followed by Group 1 and lastly Group 2. Besides, Group 3 showed a significantly higher degree of conversion (p < 0.05) than Group 1 and comparable conversion value with Group 2. Conclusions Zirconia-reinforced rice husk nanohybrid composite showed excellent shrinkage and conversion values, hence can be considered as an alternative to commercially available composite resins.

Introduction. While there are many root morphology classification systems with their own distinct advantages, there are many shortcomings that come along with each system. Objectives. The aim of this review was to compare the various root and root canal morphology classifications, their advantages, limitations, and clinical and research implications. Data Sources and Selection. An extensive literature search was conducted on PubMed and Scopus to identify the published data on root and root canal classification systems published until 1 May 2020 using keywords, root canal classification system, classification systems for root canals, and root morphology. The related literature was reviewed and then summarized. Data Synthesis. Several studies have analysed and detailed root and root canal classifications and further added new subsystems, works of Weine et al. (1969) and Vertucci et al. (1974). Besides, Sert and Bayirli (2004) added supplementary types to Vertucci’s classification system. A new classification was most recently introduced by Ahmed et al. (2017) involving the use of codes for tooth numbering, number of roots, and canal configuration. Conclusions. Weine et al. classified only single-rooted teeth, without considering multirooted teeth and complex configurations. Vertucci’s classification included complex configurations, with Sert and Bayirli adding further complex supplemental types. Ahmed et al.’s classification simplifies classifying root and canal morphology while overcoming the limitations of several previous classification systems making it beneficial for implementation in dental schools.

An untreated root canal infection usually stimulates the development of a radicular cyst. Nonsurgical root canal procedures and periapical surgery followed by placement of bone substitute will promote the healing process of the bony defect.