Fracture strength of endodontically treated lateral incisors restored with new zirconia reinforced rice husk nanohybrid composite

This study aimed to compare the fracture strength, fracture pattern and type of fracture of endodontically treated maxillary lateral incisors restored with new zirconia reinforced rice husk nanohybrid composite. Eighty mature permanent maxillary lateral incisors from patients age range of 30-60 years with single canal were selected and randomly divided into: Group 1 ? RCT + nanofilled composite (Filtek), Group 2 ? RCT + microhybrid composite (Zmack), Group 3 ? RCT + new nanohybrid composite (Zr-Hybrid) and Group 4 - Intact teeth (control). Standardized mesio-palatal-distal cavity was prepared, and endodontic treatment was carried out using crown-down technique until size 30, tapered 0.04. Obturation was completed using single cone technique with gutta-percha and AH plus sealer. Cavity access was restored with respective composite resins. Next, teeth were stored in incubator for 24 hours and subdivided into aged and unaged subgroups. Teeth in aged subgroups were subjected to 2500 thermal cycles for 5ºC, 37ºC and 55ºC with 30 seconds dwell time and 5 seconds transfer time. After that, root surfaces of teeth were covered with silicone-based material and placed in boxes filled with acrylic until the cemento-enamel-junction (CEJ) level. They were then tested under Universal Testing Machine until fracture occurred. Samples were then viewed under Leica microscope to determine the fracture pattern and type of fracture. Data analyzed using One-way ANOVA complimented by post hoc Tukey HSD and paired sample T test for fracture strength. Fracture pattern and type of fracture were analyzed using Chi-square test. Level of significance was set at p0.05). Besides, Group 3 and Group 4 showed higher rate of favorable fracture pattern, followed by Group 1 and lastly Group 2. Most favorable fracture pattern was noted to exhibit horizontal fracture type (86.36%), whereas most unfavorable fracture pattern exhibited vertical fracture type (77.78%). Endodontically treated teeth restored with new zirconia reinforced rice husk nanohybrid composite (Zr-Hybrid) demonstrated higher fracture strength than commercialized composite resins especially after artificial ageing. Zr-Hybrid showed similar fracture pattern to those of intact teeth with higher rate of horizontal fracture type

Viable approach to manage superficial enamel discoloration

Esthetics is a primary concern amongst young patients and represents a challenge to the dentist. Discolored teeth are frequently seen in the general population. Several techniques have been devised to minimize or completely eliminate tooth discoloration. This case report highlights the successful management of enamel discoloration via modified microabrasion technique followed by in office bleaching

Digital imagery: reality or fakery

“Seeing is believing” as the old adage goes, is no longer relevant to the field of dentistry in contemporary times where technological advances in softwares have facilitated the ulterior manipulation of digital radiographs as well as digital photographic images. This article attempts to highlight the software tools utilized to perpetuate digital image fraud as also the identification techniques and preventive measures to eliminate the same

Assessment of dye penetration at composite – repair interface: Effect of application of bonding agent and comparison of two different bonding systems: An in vitro study

Introduction: Reparability of defects / fractures restricted to the bulk of the composite restoration is a highly desirable property, as being less time consuming and cost effective. This study was aimed to evaluate the microleakage at the composite repair interface following surface treatment and application of the bonding agent and compared the microleakage following application of two different bonding systems at the composite repair interface. Material and Methods: Sixty composite resin specimens (Filtek Z350, 3M Dental Products) aged in distilled water for 1 week, were divided into four groups (n = 15) based on surface treatment and application of bonding agent. All the groups then received new resin applications using same composite resin. The samples were then thermocycled (200 cycles/50C to 550C{±2}) and immersed overnight in aqueous methylene blue dye solution. Single examiner carried out dye penetration analysis using stereomicroscope. Results: Mann-Whitney U-Test (p<0.05) for group one and two showed no significant difference in repair microleakage. Group 3 and 4 showed statistically significant difference when compared with group 1 & 2. However, both group 3 and 4 did not significantly differ in microleakage scores with each other.Conclusion: Irrespective of the type of bonding systems used, surface treatment with 50 micron size aluminum oxide particles followed by application of adhesive system are the essential steps to significantly reduce the microleakage at repair interface

Color Stability of a New Rice Husk Composite in Comparison with Conventional Composites after Exposure to Commonly Consumed Beverages in Malaysia

Objective. To evaluate the color stability of a new organic rice husk nanocomposite as compared to four conventional composites after exposure to commonly consumed beverages in Malaysia. Methods. One hundred and twenty-five disk samples were prepared from a new rice husk-based composite and four other conventional methacrylate-based light-cured composites of shade A2. The samples were immersed in four commonly consumed beverages: coco-based drink, kopi, Chinese tea, and teh tarik for four weeks. The color measurements were carried out every week using the reflectance spectrophotometer according to the CIE L∗a∗b∗ color system. Color changes of samples (ΔE) in each week were calculated. Statistical analysis was carried out by performing a mixed ANOVA and Tukey’s post hoc test in order to analyse the differences in ΔE. Results. The findings revealed a statistically significant difference of ΔE reading (p<0.05) among all composites immersed in all four beverages after four weeks. Rice husk composites exhibited lesser color stability as compared to Ceram.X One Universal (p<0.001) and G-aenial Universal Flo (p<0.001) but showed higher color stability compared to Solare-X (p<0.001) and Neofil (p<0.001). Coffee and Chinese tea had the most significant impact on color changes (p<0.05) observed in all composites over four weeks of study. Conclusion. Rice husk composite showed acceptable color stability. It can be considered as an alternative to conventional composites due to its eco-friendly properties