Comparison of Time Required by D-RaCe, R-Endo and Mtwo Instruments for Retreatment: An in vitro Study

Time Required for Root Canal Retreatment Using Continuous Rotation, Reciprocation, and Optimum Torque Reverse Motions: An In-Vitro Study

Objective This study aims to evaluate the time required for canal preparation using three different movement kinematics during retreatment: continuous rotational motion, reciprocating motion, and optimum torque reverse (OTR) motion. Materials and methods The sample comprised 45 single-canal mandibular first premolars. The crowns were sectioned to standardize the root length to 16 mm. The root canals were prepared using the AF Gold mechanical preparation system (25/06). The roots were obturated using the lateral condensation technique and kept at 100% humidity at 37°C for seven days. The sample was randomly divided based on the movement pattern used during retreatment into three groups (N = 15): group 1 is continuous rotational motion using the ProTaper Universal Retreatment system; group 2 is reciprocating motion using the WaveOne Gold system; and group 3 is OTR motion using the ProTaper Universal Retreatment system. The retreatment time was measured in seconds by summing two times: T1 (time to reach the apex) and T2 (time to achieve adequate cleaning). The data were statistically analyzed using a one-way ANOVA with a significance level of α = 0.05. Results The results showed that the time required for canal preparation during retreatment with WaveOne Gold files using reciprocating motion was significantly longer than the time needed with ProTaper Universal Retreatment files using continuous rotary motion or OTR motion (P < 0.05). Conclusions The use of OTR motion did not affect the canal preparation time when used with files designed for continuous rotary motion retreatment. The use of WaveOne Gold files for canal preparation during retreatment was associated with a longer working time than ProTaper Universal Retreatment files.

In Vitro Cone Beam CT Analysis of the Efficacy of Three Supplementary Steps In the Removal of Obturation Material in Endodontic Retreatment

OBJECTIVES

To evaluate and compare the efficacy of XP-endo Finisher R (FKG Dentaire, Le Locle, Neuchatel, Switzerland), EDDY (VDW Dental, Munich, Germany), and passive ultrasonic irrigation (PUI) as supplementary steps following the D-RaCe retreatment file system (FKG Dentaire) in the removal of root canal obturation material using cone beam CT.

MATERIALS AND METHODS

A total of 45 two-rooted permanent maxillary first premolars were selected. Following access preparation, cleaning, and shaping with Hero Shaper (Micro Mega, Besançon, BFC, France) rotary file up to 25/04%, thermoplasticized obturation was performed with TotalFill BC sealer (FKG Dentaire) and gutta-percha. The specimens were subjected to routine retreatment using the D-RaCe retreatment file system. Cone beam computed tomography (CBCT) and volumetric analysis were performed before and after this procedure. The samples were divided into group A (XP-endo Finisher R: n=15), group B (EDDY: n=15), and group C (PUI: n=15). Finally, a third CBCT was taken and a volumetric analysis was done. Statistical analysis was done using SPSS Statistics version 26.0 (IBM Corp., Armonk, NY, USA).

RESULTS

The lowest mean residual volume of obturation material was seen with XP-endo Finisher R (1.6 mm3), followed by PUI (1.7 mm3). The EDDY showed the least efficiency in complete debridement of the root canals (3.6 mm3). This difference in values was statistically significant.

CONCLUSION

The XP-endo Finisher R and PUI showed superior performance than EDDY in the removal of remaining obturation material from the root canal system after retreatment with the D-RaCe retreatment file system. However, none of the systems were able to completely remove the root canal obturation materials.

Retreatment of XP-endo Shaper and R-Endo files in curved root canals

OBJECTIVES

To compare the retreatment efficiency of XP-endo Shaper and R-Endo files in curved root canals using ImageJ software.

METHODS

Forty extracted mandibular first molars with curved mesial canals (25°-35°) were chosen. Access cavities, preparation and obturation of root canals were performed. Roots were randomly distributed into two groups corresponding to the retreatment files used. Group 1 retreated with XP-endo Shaper file, and group 2 retreated with R-Endo files. Each root was sectioned and photographed. ImageJ software was used to estimate the percentage of residual filling material that existed on the three root canal segments. Mann-Whitney U and the Kruskal-Wallis tests were used to compare the percentages of residual filling material between the teeth segments (P < .05).

RESULTS

The R-Endo group showed a significantly higher median percentage of residual filling material than the XP-endo Shaper group. In both groups, the coronal segments had the highest median of the residual filling material, followed by the middle and apical segments.

CONCLUSION

XP-endo Shaper is significantly more effective than R-Endo in removing root canal filling materials in the coronal, middle, and apical segments.

Comparison of full rotation and reciprocating movements in regaining apical patency during endodontic retreatment

BACKGROUND

This study aimed to compare the continuous rotation and reciprocating movements of rotary files in achieving apical patency in root canal retreatment.

MATERIALS AND METHODS

This in vitro, experimental study evaluated 64 extracted mandibular molars. The teeth were prepared up to F3 with ProTaper Universal and obturated using lateral compaction technique. The teeth were divided into four groups (n = 16) based on the mesiobuccal canal curvature (Schneider's method) and type of rotational movement. Groups 1 and 2 included straight canal teeth retreated with WaveOne Gold and ProTaper Universal Retreatment system, respectively. Groups 3 and 4 included teeth with moderately curved root canals retreated with WaveOne Gold and ProTaper Universal, respectively. Apical patency was ensured by observing the tip of a hand K-file at the apical foramen. Data were analyzed using the Fisher's exact test. P < 0.05 was considered statistically significant.

RESULTS

Apical patency was successfully achieved in all 16 teeth in group 1 (100%) and 15 teeth in group 2 (93.75%). No significant difference was noted between continuous rotation and reciprocating movements in straight canals (P = 1.00). Apical patency was successfully achieved in 15 teeth in group 3 (93.75%) and 12 teeth in group 4 (75%). No significant difference was noted between continuous rotation and reciprocating movements in moderately curved canals either (P = 0.333).

CONCLUSION

Both continuous rotation and reciprocating movements are equally effective in achieving apical patency in straight or moderately curved mesiobuccal canal of mandibular molars.