Tooth Microcracks Comparison Of Continuous Rotating And Reciprocating Rotary Files During Root Canal Biomechanical Preparation: In-Vitro Study
Continuous rotation; Dentinal defects; Dental materials; Dentinal microcracks; Endodontic instrumentation; Nickel-titanium instruments; Prosthodontic prognosis; Root canal preparation; Reciprocating motion Vertical root fracture.
AuthorsABSTRACTNewly developed nickel-titanium alloy (NiTi) instruments enable the instrument to be used with remarkable flexibility in root canals, such that the instrument can safely prepare curved root canals without the need to straighten them. There are two kinds of motion systems used when NiTi rotary instruments are applied: continuous rotating and reciprocating. In the process of biomechanical preparation, high stress concentrations inside the apical dentin create microcracks or craze lines when tools come into contact with the dentin wall surface. The study aimed to observe the effect and differences between continuously rotating and reciprocating rotary instruments on the incidence of microcrack formation on the dentin surface of tooth root canals. Thirty-two extracted mandibular and maxillary first premolar teeth were collected and divided into two groups (n=16) as per the instrumentation protocol: group I: Continuous rotating (Protaper Universal file) and group II: Reciprocating (Wave One file). Each group was subsequently instrumented with the standardized working length assigned file system. The samples were collected to be tested following instrumentation and cut to identify the microcracks under 18-24x magnification under the microscope. Pearson ChiSquare test was used to statistically analyze the data. There is no statistically significant difference in the microcrack levels for both groups, which have p = 0.110 > 0.05. The rate of microcrack in the continuous rotating and reciprocating groups was not significantly different. Most incidence of the microcracks was experienced in the apical part (9mm) in both the continuous rotating and reciprocating groups, as opposed to the coronal (3mm) and middle (6mm) parts.
INTRODUCTIONThe goals of root canal treatment are to preserve the oral cavity tooth's appearance and functionality, to get rid of bacteria and their byproducts from the root canal system, manage pain, control sepsis and abnormalities in the pulp and surrounding periapical tissue, and use the surrounding tissue to heal the damaged tooth and return it to a healthy state.1-2 The "endodontic triad" is a three-phase root canal treatment that includes biomechanical treatment (cleaning and shaping), sterilization (irrigation and disinfection), and root canal filling.1-3 Chemo mechanical root canal preparation, the process of eliminating bacteria from the root canal using mechanical instruments and antibacterial irrigation.1- 4 In the mid-1800s, the first endodontic file was made, which was a standard stainless steel K-File, the kind used mostly in dental clinics, that was manually operated.5 Subsequently, in 1963, W.F.Buehler, a metallurgist at the Naval Ordnance Laboratory in Silver Springs, Maryland, USA, discovered “nitinol”, an abbreviation for nickel (56%), titanium (44%), and Naval Ordnance • • • • • • • • • • • • • • • EJPRD ejprd.org - Published by Riset Publishing Services LLC.
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