Efficacy of Reciprocating Instruments in the Removal of Bioceramic and Epoxy Resin-Based Sealers: Micro-CT Analysis

The objective of this study was to evaluate the efficacy of reciprocating instruments in the removal of bioceramic and epoxy resin-based sealers using micro-CT analysis. Root canals of 40 extracted human teeth were instrumented with a size R25 Reciproc instrument. Specimens were randomly divided into two groups (n = 20) according to the root canal filling material. In the first group, root canals were obturated with AH Plus sealer and Reciproc R25 gutta-percha. In the second group, a combination of bioceramic gutta-percha (TotalFill BC) and bioceramic sealer (TotalFill BC) was used. After one week, the retreatment of all specimens was performed using Reciproc instruments. To analyze the differences in the filling remnants, specimens were scanned in a micro-CT device after obturation and after the retreatment procedure. Statistical analysis was performed using the Mann–Whitney U test (p < 0.05). A combination of bioceramic sealer and bioceramic gutta-percha was more effectively removed from canals using a reciprocating instrument, with a filling remnants volume of 4.01 ± 3.13 mm3, in comparison to the combination of epoxy resin-based sealer and gutta-percha (6.96 ± 2.70 mm3) (p < 0.05). A reciprocating instrument was more effective in removing bioceramic sealers than epoxy resin-based sealers, although none of the root canal filling materials were completely removed from the root canals.

Evaluation of the cutting ability of two reciprocating instruments (WaveOne Gold e W-file)

Instrumentation is a fundamental step in endodontic treatment to promote proper cleaning and shaping of the canal. The objective of this study was to compare the cutting capacity of two reciprocal nickel-titanium systems in simulated canal blocks. Sixty acrylic blocks were used, divided into two groups of reciprocal files (WaveOne Gold - WOG and W-File - WF), each with 30 blocks and divided into 3 groups (n=10) representing the first, second and third uses: WOG1, WOG2, WOG3, WF1, WF2, and WF3, respectively. Ink was injected into the simulated channels, which were covered with laminated paper to avoid affecting the instrumentation. For irrigation, 5mL of saline was used at each instrument change. At the end of instrumentation, the blocks were photographed and analyzed in a computer program to compare the results before and after instrumentation. In the statistical analysis, the tests S Shapiro-Wilk, T for independent samples and Mann Whitney were performed. Under the experimental conditions in which this study was conducted, it is concluded that there were no significant differences in apical transport after the third application. However, the instruments of the W-File group had more conservative preparations with a better centralization capacity compared to the instruments of the WaveOne Gold group, which caused preparations with a larger diameter.

Scope of Preparation of Oval and Long-Oval Root Canals: A Review of the Literature

Successful endodontic treatment depends on cleaning and disinfecting the root canals, in order to provide conditions for three-dimensional filling, which should prevent root canal reinfection. However, anatomical complexities pose a challenge during endodontic treatment. The present study was a literature review carried out in the following databases: PubMed, SciELO, and MEDLINE, which were searched for articles published from 2017 to 2021. Micro-CT studies published in English, which analysed the capacity for preparation of oval and long-oval root canals, were included. The following keywords were used: “oval-shaped canals,” “long-oval-shaped canals,” “endodontics,” and “micro-CT.” The aim of this study was to carry out a literature review of micro-CT studies on the scope of the capacity for preparation performed in oval and long-oval root canals with rotary and reciprocating instruments.

Cutting efficiency of ProDesign R, Reciproc Blue and WaveOne Gold reciprocating instruments

This study aimed to evaluate, in vitro, the cutting efficiency and time spent for instrumentation of three different heat-treated reciprocating systems in simulated straight canals. Forty-five acrylic blocks with a straight simulated root canal with 21 millimeters in length were initially weighed (P1). After weighing the blocks were divided into three groups (n = 15) and each group prepared with the following systems: ProDesign R 25.06 (Bassi/Easy, Belo Horizonte, Brazil), Reciproc Blue25.08 (VDW, Munich, Germany) and Wave one Gold (Dentsply Sirona, Ballaigues, Switzerland). The time spent for the total preparation of each block was recorded. After instrumentation, they were subjected to final weighing (P2). The difference between P1 and P2 determined the amount of material removed (cutting efficiency) by each mechanized system. The statistical analysis was performed by the ANOVA test of each of the variables, for multiple comparisons of means the turkey test was used. As for preparation time, it can be seen that ProDesign R showed a longer preparation time (P <0.5) compared to Reciproc Blue and Wave one Gold. Regarding cutting efficiency, there was no statistical difference between the groups (P> 0.5). In straight simulated canals, the type of reciprocating instrument influences the time for instrumentation; however, it shows similar cutting efficiency.