Background. Endodontic sealers are essential for sealing gutta-percha to the dentin walls. They help to ensure that the canal remains free of microorganisms which might lead to infection. In order to perform their intended function, the sealers should properly adhere to the dentin walls and remain insoluble when set in the canal. Objectives. The purpose of this study was to evaluate the bond strength and solubility of a novel polydimethylsiloxane-gutta-percha calcium silicate-containing root canal sealer (GuttaFlow ® bioseal) and compare it with the zinc oxide and eugenol sealer (Zical ®). Material and methods. The endodontic sealers used in this study were GuttaFlow bioseal and Zical. The bond strength was assessed using push-out bond strength test in 3 root segments: coronal, middle and apical. The solubility was tested according to the American National Standards Institute / American Dental Association (ANSI/ADA) specification No. 57 at 3 different time intervals: 1, 7 and 14 days. Results. The push-out bond strength in all root segments was significantly higher in Zical compared to GuttaFlow bioseal. The solubility was significantly higher on day 1 and 7 in Zical compared to GuttaFlow bioseal, and on day 14, the difference between them was not significant. Conclusions. Within the limitations of this study, the endodontic sealer GuttaFlow bioseal showed low bond strength values compared to Zical. The solubility of the set GuttaFlow bioseal and Zical were both within the recommended ANSI/ADA levels.

Aim: this study aimed to compare the sealing ability of two types of commercially available calcium silicate bioceramic based root canal sealers and a resin based root canal sealer. Methods: Twenty one single-rooted teeth were used, samples (n= 21) were randomly divided into three groups according to the sealer used (group A; ADSEAL, group B; Wellroot, group C; Ceraseal). Roots were then cleaved longitudinally in the labiolingual direction; all samples were then sectioned at three, six, and nine mm from the root tip. The penetration of sealers into the dentinal tubules was examined at 1000x with a scanning electron microscope. Data were tested for normality using Shapiro Wilk test. ANOVA test was used for analyzing normally distributed data followed by Bonferroni post hoc test for pair-wise comparison. Significance level p≤0.001. Results: groups B and C showed better sealing ability than group A in all the three sections. The coronal section showed higher sealing ability than the middle section followed by the apical section in the three tested groups. Conclusion: it can be concluded that both calcium silicate-based sealers had better sealing ability and higher bond strength than the resin epoxy- based sealer.

Background: Despite improvements and advances in materials and methods, root canal treatment is not always satisfactory. After completing the obturation procedures, retreatment might be mandatory in cases of reinfection or inappropriately cleaned root canal. Retreatment strategy involves elimination of the obturating material, and then the whole mechanical and filling procedures are repeated again. Thus, root canal sealers removal shouldn’t represent an obstacle. Objective: The current study aimed is to investigate and observe the cleanliness of root canal walls that were previously obturated with two types of calcium silicate bioceramic sealers compared to a resin sealer. Materials and Methods: 21 single-rooted premolars were utilized. After complete removal of the obturating materials using Protaper retreatment universal system, the roots were cut by the use of a hammer and a chisel, then the middle third of the retreated canals were observed under a scanning electron microscope at magnification 1000x, the amount of clear, opened dentinal tubules was compared. Results: Among the three investigated sealers, ADSEAL showed the largest number of clear dentinal tubules while, a fewer open dentinal tubule were observed with Well Root and Ceraseal. Conclusions: None of the investigated sealers could be totally removed from root canal walls. However, the quantity of remnants of root filling material with well root and ceraseal were significantly more, compared to ADSEAL.

Background;The smear layer is considered an obstacle limiting the penetration of adhesive types of cement into the dentinal tubules, thus adversely affecting the bond strength of the fiber posts. Objective;The purpose of this study was to assess the effect of ultra-sonic activation on the bond strength of fiber posts, cemented with self-adhesive cement to the root dentin.Methods; A total of 18 recently extracted single rooted premolars were selected. The root canals were prepared using ProTaper rotary, samples were obturated with Protaper universal gutta percha points. Post space was prepared using gates glidden drills, specimens were randomly divided into two groups of n=9 according to the irrigation application techniques; Group 1: conventional syringe, Group 2: ultra-sonic activation. Posts were cemented using Rely X Unicem2, bond strength was determined by pull out test.Results; A statistically significant higher mean value was recorded in Group 2 compared to Group 1.Conclusions; Ultrasonic activation can aid the irrigation with 2.6% NaOCl followed by 17% EDTA in smear layer removal, contributing in a triad way of cleaning of the root canal system and thus promoting the bond strength of fiber posts.