Eighteen-month clinical performance of preheated nanoceramic resin-based composites in Class I occlusal cavities: A randomized clinical trial.

Aims: This study aimed to evaluate the effect of preheated nanoceramic resin-based composite (RBC) (Ceram-X-Mono) placed in Class I occlusal cavities over a period of 18 months. Settings and Design: This study involves split-mouth design, randomized controlled clinical trial (RCT). Materials and Methods: One operator restored 60 Class I occlusal cavities in 24 patients. Preheating of nanoceramic RBC to 60°C for 10 min was performed before insertion of the material into 30 prepared cavities, whereas 30 restorations in the nonpreheated group were placed according to the manufacturer's instructions. Two observers evaluated the restorations using Federation Dentaire Internationale (FDI) criteria at baseline, 6, 12, and 18 months. Statistical Analysis: Kappa index, Friedman and Wilcoxon matched pair test, and Krushal-Wallis and Mann-Whitney tests were used for statistical analysis. Results: 100% retention rates were seen in both the groups. In nonpreheated group, significant difference was observed for surface staining (P = 0.0001), color stability (P = 0.0277), anatomic form (P = 0.0431), and marginal adaptation (P = 0.0051), whereas in preheated group, significant increase in surface staining (P = 0.0051) was recorded. There was a statistically significant difference observed between the preheated and nonpreheated groups at different time periods for the tested clinical parameters. Conclusion: Within the limitations of this RCT of 18 months, preheated nanoceramic RBC restorations showed better clinical performance compared to nonpreheated group.

Effect of Fluoride Recharge on the Microleakage of Fluoride-Releasing Restorative Materials: An Ex Vivo Confocal Laser Scanning Microscopy Study.

Context: Success or failure of a restoration depends on its ability to bond to the tooth structure, to reduce microleakage, and to inhibit secondary caries. Fluoride-releasing materials have the inherent potential to release fluoride and are also capable of recharging themselves with topical agents. Aim: The aim of this study was to compare and evaluate the effect of fluoride recharge on microleakage of different restorative materials. Materials and Methods: Eighty extracted teeth were collected and split mesiodistally into 160 specimens. Class V cavities were prepared on buccal and lingual surfaces. Specimens were divided into four groups of 40 each based on the restorative material. Group I: Glass ionomer; Group II: Resin composite; Group III: Giomer; and Group IV: Alkasite. The restored teeth were stored in artificial saliva. Each group was divided into four subgroups for fluoride recharge and subsequent confocal laser scanning microscopy (CLSM) examination: (A) no fluoride recharge and CLSM examination after 24 h, (B) no fluoride recharge and CLSM examination after 3 weeks, (C) fluoride recharge once at third week followed by CLSM examination at 6 weeks, and (D) fluoride recharge twice at third week and sixth week followed by CLSM examination at 9 weeks. Statistical Analysis: Kruskal-Wallis and Mann-Whitney U tests were performed to analyze the obtained data. Results: A significant difference in microleakage was noted among resin composite and other groups except Cention-N, whereas no significant difference was noted pre- and post-fluoride recharge. Conclusion: Increased microleakage was noted post-fluoride recharge, although statistically not significant.

Effect of ultrasonic activation of photosensitizer dye temoporfin (Foscan) on antimicrobial photodynamic therapy: An ex vivo study.

AIM: The aim of this study is to evaluate the effectiveness of ultrasonic activation of photosensitizer (PS) drug Foscan in the elimination of endodontic pathogen from root canal system. MATERIALS AND METHODS: The minimal bactericidal concentration of "Foscan" was determined using disc diffusion and broth dilution method. Forty-eight extracted single-rooted premolars with periapical pathology were used for the study. After access opening, the first microbial sample was taken. The teeth were then randomly divided into four groups: Group 1: Chemomechanical debridement (CMD), Group 2: CMD and passive ultrasonic irrigation (CMD + PUI), Group 3: CMD and antimicrobial photodynamic therapy (aPDT), and Group 4: CMD and aPDT with activation by ultrasonics. After antimicrobial protocols, the second microbiological sample was collected. The samples were analyzed by multiplex polymerase chain reaction for the effectiveness of four antimicrobial protocols on Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, and Treponema denticola. STATISTICAL ANALYSIS USED: Wilcoxon signed-rank test and Mann-Whitney U-test with the significant level P < 0.05, using IBM SPSS statistics 20 version software. RESULTS: Foscan at concentration of 3.125 µg/ml was chosen for antimicrobial analysis. The prevalence of T. denticola, F. nucleatum, P. gingivalis, and P. intermedia was 79.17%, 70.84%, 70.83%, and 58.33%, respectively. Group 4 showed highest bacterial reduction of 99.51%, followed by Group 1 which showed bacterial reduction of 97.35%. CONCLUSIONS: Foscan can be used as an effective PS dye at low concentration with minimal tendency for tooth discoloration. Ultrasonic activation of PS dye facilitated better diffusion into dentinal tubules and biofilm obtaining greater bacterial reduction.

A Stereomicroscopic Evaluation of Dentinal Cracks at Different Instrumentation Lengths by Using Different Rotary Files (ProTaper Universal, ProTaper Next, and HyFlex CM): An Ex Vivo Study.

Introduction. The aim of the present study was to evaluate the dentinal cracks after root canal preparation with rotary files: Gates Glidden, ProTaper Universal, ProTaper Next, and HyFlex CM at different instrumentation lengths. Methodology. Sixty-five mandibular premolars were mounted in the acrylic tube with simulated periodontal ligaments and the apex was exposed. The root canals were instrumented with different rotary files, namely, ProTaper Universal, ProTaper Next, and HyFlex CM, to the major apical foramen (AF), short AF, and beyond AF. The root apex was stained with 1% methylene blue dye and digital images of apical surface of every tooth were taken and development of dentinal defects was determined by using stereomicroscope. Multinomial logistic regression test was performed to identify influencing factors. Results. Instrumentation with rotary files terminated 2 mm short AF and did not cause any cracks. Significantly less cracks were seen when instrumentation with rotary files terminated 1 mm short apical foramen when compared with the instrumentation terminated at or beyond apical foramen (p < 0.05). Conclusion. ProTaper Universal rotary files caused more dentinal cracks than ProTaper Next and HyFlex CM. Instrumentation short AF reduced the risk of dentinal defects.