Microcomputed tomographic evaluation of 6 NiTi files on the pericervical dentin and the smallest dentin thickness zones in mesial root canals of mandibular molars: an in vitro study

OBJECTIVE

The aim of this study was to evaluate six files on the pericervical dentin (PCD) and the smallest dentin thickness zones (SDTZ) in mesial root canals of mandibular molars.

MATERIALS AND METHODS

Sixty mandibular molars with two mesial canals and Vertucci configuration were aleatory allocated in 6 experimental groups of 10 molars and 20 root canals. Specimens were scanned before instrumentation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WaveOne Gold (WG), group 2 with Reciproc Blue (RB), group 3 with TRUShape (TS), group 4 with XP-endo Shaper (XP), group 5 with iRace (IR), and group 6 with TruNatomy (TN). After instrumentation, the molars were scanned again and the images recorded were reconstructed with the NRecon v.1.7 (Bruker micro-CT) and analyzed with CTAn v.1.20.8 software (Bruker micro-CT) quantifying the changes produced in the surface, volume, structure thickness, SMI, and centroids at the Pericervical Dentin area of the root canals (PCD) located from the root canal orifices at the floor of the pulp chamber to 4 mm in the apical direction, and the changes in the Smallest Dentin Thickness Zones (SDTZ) located (from the furcation to 4 mm and 7 mm in the apical direction. The data obtained were compared using Wilcoxon and ANOVA with a 5% significance level.

RESULTS

XP and TN were similar in all the parameters (P >.05) at the PCD, but TN showed significant differences from WG, RB, TS, and IR (P <.05), while XP showed significant differences from WG (P <.05) in volume, surface, and structure thickness. Regarding the changes in the SDTZ, the amount of dentin removed was similar between the groups in both canals at the middle 1/3, at the cervical 1/3 for MB canals, and in ML canals for RB, TS, XP, IR, and TN (P>.05). The action of WG was significantly different from that of XP and TN in the cervical 1/3 of the ML canal (P <.05).

CONCLUSIONS

XP and TN rotatory files with small taper and volume maintained better with minor changes at the PCD and SDTZ, while WG reciprocation file produced the largest change. All the files were maintained centered at the PCD, and their performances were safe with a minimal thickness higher 0.5 mm at the SDTZ, and without risk of perforation.

TRIAL REGISTRATION

No clinical trials were indicated in this study.

CLINICAL RELEVANCE

The choice of endodontic files is a relevant factor in the conservative performance of root canal treatments.

Assessment of minimally invasive file systems on resistance to fracture using traditional and contracted access cavity designs in the maxillary first and second molars

Objective

The objective of the study was to evaluate the effect of access cavity design on fracture resistance of the extracted maxillary first and second molars prepared with three minimally invasive files.

Materials and Methods

One hundred and twelve extracted human maxillary molars were selected for the study and divided randomly into three groups according to different minimally invasive files used (self-adjusting files [SAF], XP-endo Shaper [XP], and 4 V-Taper 2H [VT]) and one control group (CG). All experimental groups were subdivided into two subgroups, i.e., conservative access cavity (CAC) and traditional access cavity (TAC). All the canals in different experimental groups were enlarged up to apical size 30. The data were analyzed using the analysis of variance and Post hoc Tukey tests (P < 0.05).

Results

The highest mean fracture resistance of teeth with CAC was of the CG (1399.957), followed by teeth with CAC instrumented by SAF (1378.314) and XP-endo Shaper (1202.929). The least value was of the V-Taper file system (937.157). Furthermore, the highest mean fracture resistance value of teeth with TAC was of the CG (1143.171), followed by teeth with TAC instrumented by SAF (1150.607) and then XP-endo Shaper (998.150). The least value was of the V Taper file system (757.050).

Conclusion

Conservative endodontic access (CAC) in the maxillary molars had shown significantly increased fracture resistance over TAC. SAF showed the maximum fracture resistance, while V-Taper files showed the least fracture resistance among the experimental groups compared.

Comparison of Postoperative Pain After the Utilization of Different File Systems in Single Visit Endodontics

Purpose

This prospective single-blind, parallel-group, randomized clinical trial was aimed to compare the effect of three different rotary instrumentation systems ProTaper Next (PTN), Self-Adjusting File (SAF) and XP-endo Shaper (XPS) on postoperative pain and analgesic intakes.

Patients and Methods

A total of 159 molars diagnosed with symptomatic irreversible pulpitis were randomly divided into three study groups according to the instrumentation techniques: PTN (n = 54), SAF (n = 52), and XPS (n = 53). The preoperative pain scores were taken before the onset of treatment in the groups. After a single appointment for root canal treatment, the patients were asked to rate the level of their pain according to the Visual Analog Scale (VAS) of 100 mm at 6, 24, 48, and 72-hour post-treatment intervals. Ibuprofen was prescribed to be taken while experiencing pain; patients were requested to note the number of pills consumed at intervals after treatment.

Results

The patients in SAF and XPS groups had lower mean VAS scores than the PTN group at 24-, 48-, and 72-hour intervals (p < 0.05). The most common analgesic intake was optimally seen in the PTN group at a 6-hour interval. All shaping procedures caused postoperative pain, whose intensity decreased with time.

Conclusion

The SAF and XPS groups had a lesser intensity of pain as well as minimum analgesic intakes as compared to the PTN group. All instrumentation systems moderately caused pain, and the PTN group experienced the highest pain among others.

Biofilm elimination from infected root canals using four different single files

INTRODUCTION

Enterococcus faecalis (E. faecalis) is the most commonly isolated bacterium from infected root canals. It is found in the form of a biofilm, which makes it more resistant to antimicrobials, and requires optimal chemomechanical strategies to maximize root canal disinfection.

AIM

To evaluate the efficacy of 4 different endodontic file systems against E. faecalis biofilm growth in root canals using colony-forming units per milliliter (CFU/mL) and scanning electron microscope (SEM).

METHODS

Eighty-five extracted human mandibular premolars with straight root canals and apical diameters not larger than the #15 K-file were randomly selected. After performing a pilot study (n = 15) to determine the ideal incubation period for E. faecalis biofilm development, sixty-five root canals were infected with E. faecalis, incubated for 3 weeks, and then mechanically prepared using one of four single files (XP-endo Shaper, Hyflex EDM, One Curve, and Fanta. AFTM F One) (n = 15). Five infected root canals were excluded for the positive control. Five non-contaminated root canals were included for the negative control. Samples were collected using sterile paper points pre- and post-instrumentation to determine the bacterial load (CFU/mL). Root canals from each group were topographically evaluated at the coronal, middle, and apical segments using scanning electron microscope (SEM). Bacterial reduction data were estimated and statistically analyzed by Kruskal-Wallis and Mann-Whitney U tests (post hoc test) (P ≤ .05).

RESULTS

XP-endo Shaper, Hyflex DEM, and One Curve significantly could eradicate E. faecalis biofilms in infected root canals with no significant difference among them compared to Fanta. AF™ F One.

CONCLUSION

None of the systems were capable of completely eliminating biofilms. XP-endo Shaper, Hyflex EDM, and One Curve mechanically eliminated E. faecalis biofilms compared to Fanta. AF™ F One from infected root canals.

Postoperative Pain after Use of the WaveOne Gold and XP-endo Shaper Systems: A Randomized Clinical Trial

INTRODUCTION

The present study aimed to clinically compare the incidence of postoperative pain after endodontic treatment of posterior teeth using the WaveOne Gold (WOG; Dentsply Sirona, Ballaigues, Switzerland) and XP-endo Shaper (XPES; FKG Dentaire, La Chaux-de-Fonds, Switzerland) systems.

METHODS

In a single-blind randomized clinical trial, 148 vital teeth with an indication for conventional endodontic therapy for prosthetic purposes were treated by 5 specialists following a preestablished protocol. All participants were unaware of the treatment they received. The teeth were randomly divided into 2 groups (n = 74) according to the instrumentation system used (the WOG group and XPES group). The treatments were performed in a single session. The participants were asked to rate the intensity of postoperative pain on a visual analog scale (no pain, mild pain, moderate pain, and severe pain) after 24, 48, and 72 hours and 7 days.

RESULTS

The incidence of postoperative pain was higher in the XPES group after 24, 48, and 72 hours compared with those in the WOG group (P < .05). Two participants in the WOG group experienced severe postoperative pain after 24 hours. None of the participants in either group reported pain after 7 days (P > .05, Mann-Whitney test).

CONCLUSIONS

Postoperative pain is expected after preparation of the root canal system with the WOG and XPES systems tested, but it only persists for a short period. Although more common after the use of the XPES system, the pain was classified as mild at all time points.

Micro-computed Tomographic Assessment and Comparative Study of the Shaping Ability of 6 Nickel-Titanium Files: An In Vitro Study

INTRODUCTION

This research studies and compares the shaping ability of WaveOne Gold (WG; Dentsply Tulsa Dental Specialties, Tulsa, OK), the Reciproc Blue (RB; VDW, Munich, Germany), TRUShape (TS, Dentsply Tulsa Dental Specialties), XP-endo Shaper (XP; FKG, La Chaux-de-Fonds, Switzerland), iRace (IR, FKG), and TruNatomy (TN; Dentsply Sirona, Ballaigues, Switzerland) in the preparation of moderately curved canals and using micro-computed tomographic technology.

METHODS

Sixty lower molars with 2 mesial canals were randomly distributed into 6 groups of 10 molars and 20 canals per group (n = 20). Specimens were scanned before and after preparation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WG, group 2 with RB, group 3 with TS, group 4 with XP, group 5 with IR, and group 6 with TN. After instrumentation, researchers quantified the changes produced in the canal geometry in terms of surface, volume, structure thickness, surface convexity index, structure model index, percentage of surface touched, and centroids. Wilcoxon and analysis of variance tests were performed to compare the values before and after preparation and the differences between groups. The significance level was established at 5%.

RESULTS

There were no significant differences between WG and RB (P > .05) and between TN and XP (P > .05). TN had significant differences with WG, RB, TS, and IR (P < .05). All the files produced similar apical transportation (P > .05).

CONCLUSIONS

WG and RB and TN and XP had similar shaping effectivity. TS and WG touched the highest percentages of canal surfaces (81% and 73%, respectively) but produced the biggest changes in the canal anatomy. TN and XP better kept the canal anatomy, but TN touched the lowest percentage of canal surface (50%). All the files used were able to clean and to shape moderately curved canals with minimal apical transportation.

Influence of rotational speed and glide path on cyclic fatigue resistance of XP-endo shaper

Aim

The aim of this study was to evaluate the effect of the different rotational speeds and creating a glide path on cyclic fatigue resistance of XP-endo Shaper® (XPS) (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) at intracanal temperature.

Materials and Methods

Ninety-six XPS files were divided into 6 groups [directly used at 1000 rpm (G1) or 3000 rpm (G4), with glide path at 1000 rpm (G2) or 3000 rpm (G4), without glide path at 1000 rpm (G3) and 3000 rpm (G6)]. All the instruments were rotated in a stainless-steel artificial canal with a 75° angle of curvature, 7.5 mm radius of curvature, and 1.3 mm inner diameter until the fracture occurred. The number of cycles to failure (NCF) and the length of the fractured (LF) segments were evaluated. Weibull analysis, one-way ANOVA, and Tukey multiple comparison tests were performed with the significance level set at 0.05.

Results

NCF of 3000 rpm groups was statistically higher than that of 1000 rpm groups (P < 0.05). And time to fracture was found statistically higher in 1000 rpm as compared to 3000 rpm. The mean LF of the instruments was statistically insignificant (P > 0.05). There was no statistical difference within the groups subjected at 1000 rpm and 3000 rpm files used with or without a glide path (P > 0.05).

Conclusion

Within the limitations of this in vitro study, it was determined that XPS can be used safely even at 3000 rpm speed with or without glide path.

Cone-Beam Computed Tomographic Analysis of Shaping Ability of XP-endo Shaper and ProTaper Next in Large Root Canals

INTRODUCTION

The aim of this study was to evaluate and compare the shaping abilities of the XPS (XP-endo Shaper) and PTN (ProTaper Next) systems by using cone-beam computed tomography on apical, middle, and coronal thirds of the pre-created large canals with different apical sizes.

METHODS

Seventy-two teeth with single canal were divided into 3 groups, and then large root canals were created with apical diameter #30 (Group 1), #35 (Group 2), or #40 (Group 3) by using hand files. Each group was again divided into 2 experimental groups, and root canals were instrumented with either XPS or PTN. Canals were scanned before and after instrumentation by using cone-beam computed tomography scanner to evaluate mesiodistal transportation, buccolingual transportation, centering ratio, percent increased prepared area (PA) (mm²), and percent increased prepared outline (PO) (mm) at 2, 5, and 8 mm from the apex. Data were statistically analyzed, and the significance level was set at P < .05.

RESULTS

There were no statistically significant differences in PA, PO, and centering ratio values between instruments in size 30 and size 35. The mean increases in PA and PO (P < .021) were statistically higher with XPS in size 40. PTN had statistically higher buccolingual transportation in size 30 and size 35. XPS had lower mesiodistal transportation values in all 3 apical sizes.

CONCLUSIONS

PTN system is able to remove the dentin even in cases of increased apical diameter. However, XPS has less canal transportation and better centering ability compared with PTN.