Study On Time-Efficiency And Debris Extrusion Of Reciproc Single-File Reciprocationg Ni-Ti System

Canal preparation is one of processes in root canal treatment (RCT). Debridement, instrumentation and irrigation are three main steps in the procession of canal preparation. The outcomes, efficiency and safety of RCT majorly depend on the instruments used in therapy. Reciproc system by VDW is a novel sing-file Ni-Ti system that applies the reciprocating movement for canal preparation. Applying reciprocating movement, the operator can finish one root canal preparation by only one instrument, without changing file during the process.Objective:The aim of this study is comparing the timing efficiency, the weight of extrusive debris though the apex, and the occurrence of instrument fracture of Reciproc system and conventional used Mtwo system while using them for curved root canal preparation, to make assessment to the new Reciproc system and give discuss to choose appropriate instrument in clinical practice.Method:36intact and well-developed mesial-buccal root canals in extracted molar teeth were collected^serially numbered and evenly divided into two groups:Reciproc Group(Group R) and Mtwo Group(Group M). Each of the root canals had a25°or more curvature determined by Schneider’s Method. The teeth were treated in0.5%thymol solution for two days, stored in3%Hydrogen peroxide for a week, and then preserved in0.9%physiological saline. The pulp were exposured and removed by regular ways. The working length(WL) and curvature of each canal were measurated by X-ray and then recorded. Using Reciproc and Mtwo to prepare canals in each group in the standard operation specification according to the instructions. The root canals were irrigated by3%hydrogen dioxide solution and5.25%sodium hypochlorite solution alternately. The operation time, the occurrence of instrument fracture were recorded. The extrusive debris were collected by self-made container according to standard installation introduced by Myers GL and Montgomery S and weighed.Result:Among two groups, Group R markedly took much less time for preparation comparing to Group M(P<0.05) under the condition of similar canal anatomy. The weights of extrusive debris from Group R and Group M showed no significant differences (P>0.05). During the study, no instrument fracture occurred with Group R, while one15/05file and one20/06file broken in Group M.Conclusion:When applied in curved canals, Reciproc is more time-saving than Mtwo. The extrusion debris of Reciproc and Mtwo shows no significant differences. Reciproc has less incident of instrument fracture than Mtwo under same using times.