Influence of reuse and cervical preflaring on the fracture strength of reciprocating instruments

Abstract

Objective:This study sought to assess the influence of cervical preflaring and reuse after resterilization, on fracture strength and plastic deformation and/or surface cracking in reciprocating nickel–titanium [NiTi] endodontic instruments after root canal instrumentation of extracted human teeth.Materials and Methods:Forty engine-driven reciprocating NiTi instruments (20 Reciproc® [RC], VDW; 20 WaveOne® [WO], Dentsply) were used in root canal instrumentation of extracted human molars. A total of 485 human upper molars with similar anatomical features were selected and randomly distributed across four groups according to the instrumentation procedures performed (G1 and G3: RC; G2 and G4: WO). Reciprocating instruments were used as per manufacturer instructions. In groups G3 and G4, cervical preflaring was performed prior to instrumentation. After each use of each instrument, sterilization was repeated and scanning electron microscope (SEM) images were obtained to check for plastic deformations and/or cracks on instrument surfaces. Each instrument was used repeatedly until fracture occurred.Results:Regardless of flaring, RC files exhibited greater fracture strength than WO instruments (P <0.01) with and without preflaring. Cervical preflaring significantly reduced the risk of instrument fracture (P <0.01). No plastic deformations were observed before fracturing. However, cracks were found on WO instruments shortly after their first use. RC and WO instruments resisted fracturing after autoclave sterilization.Conclusions:Cervical preflaring allowed a significant increase in the number of times RC and WO files could be reused safely.

Effects of resterilization and storage time on sterility of paper/plastic pouches

“…Most studies regarding resterilization focus on medical/dental instruments themselves, not on the packaging. [ 10 11 ] Even though packaging material is also an important factor in sterility maintenance.…”

Comparison of Canal Transportation and Centering Ability of ProGlider and WaveOne Gold Glider in Curved Canals

“…Pre-enlargement provided by the glide path allows the root canal preparation instruments to work with less torsional stress, reducing the risk of instrument fracture. 1,[3][4][5][6][7][8][9] Although not statistically significant, the highest mean transportation values have been observed when the glide path is not prepared before the final canal instrumentation. 1 Therefore, the performance of the file system might be enhanced by preparation of a glide path before the final shaping.…”

“…Pre-enlargement provided by the glide path allows the root canal preparation instruments to work with less torsional stress, reducing the risk of instrument fracture. 1 3 4 5 6 7 8 9 …”

Undergraduate Students’ Acceptance of a Reciprocating One-File System for Endodontic Treatment

“… 3 Furthermore, the fact that the tested system allows a preparation without glide path 1 2 might have eased the use especially for the less trained clinician, even though in the students’ education, a glide path was always created interalia due to the increased fracture strength. 18 As a future recommendation, a comparison between rotating and reciprocating systems among students would be surely of interest. Despite the limitations of a survey assessment study, our results show that Reciproc blue is a safe and well-accepted system even for less-experienced users.…”