Histopathological Study of Periapical Inflammation Following Preparation of the Root Canal with Conventional and Profile Rotary Instrumentation in Teeth of Cats

Statement of Problem: Various factors are involved in causing inflammation following root canal treatment. Controlling these factors may relieve the related pain. One of these factors is extrusion of debris beyond the apex. Although debris extrusion happens in all instrumentation techniques, researchers have declared that in coronal flaring technique,there is minimum debris extrusion.Purpose: The purpose of this study was to evaluate and compare the inflammation of periapical area following root canal therapy, using conventional and profile rotary instrumentation in cats' teeth, from a histopathological point of view.Materials and Methods: This experimental study conducted on thirty Persian one year old cats. Three groups of samples were chosen and treated with different methods. First group were prepared by step-back instrumentation technique using stainless steel Ktypefiles. Second group were prepared by crown down technique using Ni-Ti files.Third group were prepared using profile GT rotary system at 150-rpm speed. Animals were subjected to vital perfusion at 8, 24 & 48 hour intervals after instrumentation. The canine teeth were separated from the jaw along with some of the supporting structures.Then decalcification and laboratory processing were carried out and samples were evaluated histologically. Collected data were analyzed using Kruskal-Wallis test.Results: The results showed that in vital teeth with no evidence of periapical pathosis,the inflammation following various instrumentation methods was not statistically different.Conclusion: In vital teeth, the periapical inflammation following various methods of instrumentation is not statistically different

Histologic evaluation of repair of mechanical furcal perforations in dog premolars, using gray MTA, white MTA & Portland cement

Background and Aim: Furcal perforation has a great impact on prognosis of endodontic treatments, requiring immediate and proper intervention. Gray MTA is applied as material of choice in repairing perforations. The aim of this study was to evaluate the repair of mechanical furcal perforations, histologically using white MTA and Portland cement and compare them with gray MTA. Materials and Methods: In this experimental study, second to fourth mandibular and maxillary premolar teeth of five dogs received endodontic treatment, then the furcation area of the teeth were perforated and repaired as follow: gray MTA in group1, white MTA in group 2, Portland cement in group 3 and cotton pellet in group 4 (control). Animals were controlled for 4 months and sacrificed using an over dosage of sodium thiopental intravenous injection and perfusion of 10% formaldehyde. Chi-square and Fisher exact tests were used to compare hard tissue formation between groups and between each two groups, respectively. Non-parametric Kruskall Wallis and Dunn procedure were also used to compare degree of inflammation among groups and between each two groups, respectively. Results: Gray MTA had more favorable results (90.9% hard tissue formation and only 9.1% severe inflammation) but the difference between gray MTA, white MTA and Portland cement was not statistically significant. Conclusion: The difference between gray MTA, white MTA and Portland cement groups was not statistically significant for degree of inflammation and hard tissue formation. In conclusion both white MTA and Portland cement can be used instead of gray MTA to repair perforations in accordance to esthetic considerations