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Assessment of growth factors with three different platelet preparations namely platelet rich fibrin, platelet rich plasma and lyophilized platelet-An invitro study Abstract Enhancing wound healing with patients own blood, particularly the platelet preparations have gained more popularity recently. These platelets excrete large amount of growth factors and cytokines that are associated with the healing process and regeneration. Even though these platelet concentrates are widely used in various forms, the mechanism behind that remains unclear. Therefore, this study aims at investigating the levels of growth factors in three different platelet preparations namely platelet rich plasma (PRP), platelet rich fibrin (PRF) and lyophilized platelets. Materials and Methods Autologous blood for preparing the platelet preparations was obtained from healthy donors aged between 25 to 35 years. The samples were then divided into three experimental groups. The preparation of PRP was done with the addition of anticoagulant and the PRF is prepared without adding it. The platelet counts in the blood were analyzed and the growth factors were quantitatively measured using ELISA reader. The statistical analysis was performed by using the Chi square test. Results In the quantitative analysis of growth factors LPL showed significant increase of the liberation of growth factors compared to PRP and PRF. Conclusions With the various recent advances in technologies for preparing these platelet concentrates this can be widely used in clinical practice more accurate in the future.

Aim and objective The present study aimed to assess the formation of microcracks in root dentin post-instrumentation with nickel–titanium (NiTi) hand and rotary file system. Materials and methods Totally, 80 freshly extracted mandibular premolar teeth with single roots were chosen for this study. Access opening was performed and #10 K-file was used to attain patency of canal. All specimens were divided into four groups (each group having 20 specimens), i.e., Group I: Unprepared, Group II: NiTi hand K-files, Group III: Self-adjusting file, and Group IV: XP-Shaper single file. Complete irrigation of all the canals was performed after instrumentation. All roots were cut horizontally at three levels [apical third (3 mm), middle third (6 mm), and cervical third (9 mm)] from the apex with diamond disc. A stereomicroscope was used to view the sections under 20× magnification. Results Self-adjusting file showed least number of defects with a percentage of 75% followed by XP-Shaper and NiTi hand K-files with a values of 65 and 60%, respectively. Use of hand K-files resulted in greater number of incomplete cracks (30%) and use of XP-Shaper demonstrated greater number of craze lines (15%). A statistically significant difference was found between the experimental groups in the formation of dentinal defects of root at apical third (3 mm) (p < 0.031) and middle third (6 mm) (p < 0.001), whereas the sections at cervical third (9 mm) did not show any statistically significant difference (p > 0.312). Conclusion The present study concluded that the self-adjusting file system gives promising better results in cleaning ability with minimal incidence of radicular dentin microcracks than XP-Shaper and NiTi hand K-files system. Clinical significance The root dentin may unavoidably get damaged during instrumentation resulting in the formation of dentinal cracks and tiny complicated fractures, thus leading to endodontic failures. Various factors cause dentinal cracks, but the flexibility of file due to heat treatment, kinematics of the file, and the basic architecture of the file are the most significant ones. Self-adjusting file system represented satisfactory results with minimal microcracks defects. How to cite this article Kumar A, Kaul S, Kuriakose F, et al. Evaluation of Radicular Dentin Microcracks Formation after Instrumentation with NiTi Hand and Rotary File System: A Stereomicroscopic Study. J Contemp Dent Pract 2020;21(11):1233–1237.

Aim: The aim of the study was to assess the reaction of different final irrigants to the bond strength of root dentin exposed to chloroform. Materials and Methods: Fifty extracted maxillary central incisors were selected. Working length was determined, and canal was instrumented with ProTaper rotary system (Dentsply Maillefer) till F4 file. The specimens were then divided into five groups ( n = 10). Group 1: not disclosed to any root canal solvent, Group 2: disclosed to chloroform for 5 min, Group 3: chloroform for 5 min followed by absolute alcohol, Group 4: chloroform for 5 min followed by chlorhexidine (CHX), And Group 5 – chloroform for 5 min followed by saline. The canals were obturated with F4 gutta-percha cones with AH Plus sealer. The samples will be sectioned horizontally into 1 ± 0.1 mm thick slices. The push-out bond strength was performed in a universal testing machine. Results were statistically analyzed by one-way analysis of variance. Results: There existed a significant difference between the mean push-out bond strength of different groups. Irrigation with chloroform negatively affected the bonding between root canal sealer and root dentine. Absolute alcohol significantly improved the bond strength values. Conclusion: Exposure with chloroform during the retreatment will decrease the bonding between sealer (AH Plus) and root dentine. The use of absolute alcohol as a final irrigant improved the bonding between sealer and dentin. CHX and saline showed no improvement in bond strength.