Effects of Sodium Hypochlorite Irrigation on Dentine Hardness

• Main Authors: Shahbaz Ahmed, Fazal-ur- Rehman Qazi, Yawar Ali Abidi
• Format: Article
• Language: English
• Published: Dow University of Health Sciences 2010-09-01
• Series: Journal of the Dow University of Health Sciences
• Subjects: dentine; hardness; vickers hardness number
• Online Access: http://www.jduhs.com/index.php/jduhs/article/view/176

Introduction: An endodontic treatment consists of removing all contents of the root canal system during the shaping phase.Irrigation is presently the best method for the removal of tissue remnants and dentine debris during instrumentation. Irrigationsolutions also provide gross debridement, lubrication, and destruction of microbes and dissolution of tissues. The aim of this studywas to investigate the effect of the two different concentrations of sodium hypochlorite (5.25% and 2.25%) on hardness of dentin. Materials and Methods: Forty eight single rooted extracted human teeth were selected, and preserved in sterile water. Crownsof the teeth were sectioned from the roots at the cemento-enamel junction using a diamond bur in a high-speed hand-piece.Cleaning and shaping of the roots using K-files was commenced. Canals were irrigated with 1 ml of sterile water after eachfile used. After that each root was placed in the brass holder of a diamond wheel saw and transversely sectioned into cervical,middle and apical sections, each of 3 mm thickness. The apical surface of the root sections were covered with an adhesivetape to seal the canal entrance and then placed upside down (i.e. with the coronal surface lowermost) on a sticky sheet in apolypropylene ring frame. Self-cure acrylic was mixed to a thin consistency and poured into the frame until the root sectionwas covered. Each acrylic disc was then polished using sand paper of decreasing abrasivity until a smooth surface was achieved,and then dried. Hardness testing was carried out using a Wallace Hardness Tester. After measurement of the initial hardness,specimens were randomly allocated into two groups, each of 24 roots and treated in two different concentrations of irrigationsolutions (5.25% and 2.25%). Final hardness was measured and compared. Results: Data obtained from the test was analysed using SPSS (Version 15.0, SPSS Inc., USA). Descriptive analysis wasexecuted in form of mean ± standard deviation for Hardness of each group. Paired “t†test was used to evaluate the significanceof difference in the dentine hardness within the groups. The level of significance was set at 0.05. Analysis showed that therewas a significant decrease (p=0.00) in the hardness of dentine after treatment with 2.25% and 5.25% sodium hypochloriteconcentrations. The level of significance was set at 0.05. Conclusion: Irrigation with 2.25% and 5.25% concentrations of sodium hypochlorite resulted in a statistically significantdecrease in hardness of root dentine both for the whole root and at coronal, mid and apical levels at 1mm depth.