THE EFFECT OF ROOT CANAL PREPARATION BY THREE DIFFERENT NITI FILE SYSTEMS ON DEVELOPMENT OF DENTINAL MICRO CRACKS.

Abstract

Cleaning and shaping with NiTi files has been shown to be associated with an increased incidence of dentinal micro cracks. There is no definitive perspective on whether small dentinal cracks can lead to root fracture. The present study was taken with the aim of evaluating root micro cracks caused by the different NiTi rotary systems such as ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland) ProTaper Next, Wave One Gold and Diaket. Hundred human premolars extracted teeth for orthodontic reasons were divided into five groups of 20 each. Samples in each of the groups were instrumented with the given files and one group was left as control.  Roots were sectioned horizontally at 2 mm, 4 mm, and 6 mm from the apex. Images of each section were captured at 20X magnification using a digital camera attached to stereomicroscope. Only two distinct categories were established as ‘‘no defect’’ and ‘‘defect’’. The incidence of dentinal defects between the groups was analysed by using the Pearson Chi-Square test at a significance level of P < .001. Results of this study shoe that differences have been found between NiTi rotary systems with regard to induction of dentinal micro cracks and also in relation to the specific third of the root (apical, middle or coronal) affected. Protaper Universal has been found to cause maximum dentinal micro cracks with maximum at apical third of roots. Wave One Gold causes very less micro cracks in dentin.
Keywords: NiTi, Dentsply Maillefer, Ballaigues