Apical extrusion of intracanal bacteria following use of two engine-driven instrumentation techniques

COMPARATIVE EVALUATION OF THE EFFECT OF DIFFERENT ROTARY INSTRUMENT SYSTEMS ON THE AMOUNT OF APICALLY EXTRUDED DEBRIS

Objectives: The purpose of our study is to examine in vitro the amount of debris extrusion from the apical after root canal preparation with different rotary instruments. Materials and Methods: In present study, 60 single root single-canal lower premolar human teeth were used. The teeth were randomly selected and divided into 4 main groups (n=15). Root canals are shaped by using 2Shape, One Curve and XP-3DEndo Shaper working in rotational motion and WaveOne Gold working reciprocal motion. Later, the weight of each eppendorf tube was weighed on a precision scale and the amount of debris extrusion from the apical was determined with 10ˉ4 precision by subtracting the empty weight of the tube. Since the parametric test assumptions were fulfilled in the evaluation of the data obtained regarding the amount of debris extrusion from the apical of file systems by loading them into the SPSS 22.0 program, One-Way Variance analysis was used and the level of error was taken as 0.05. Results: When the amount of debris extrusion from the apical is ordered from high to low, it was seen that there are 2Shape, One Curve, XP-Endo Shaper, WaveOne Gold. However, the difference between study groups was not statistically significant (p> 0.05). Conclusions: Considering the results obtained in terms of debris extrusion from the apical about the new generation files with different metallurgy, kinematics, structural features, designs and different configurations that we used ın present study, it was seen that these systems would not show any difference in terms of the effect of debris on the success of endodontic treatment.

A critical appraisal of research methods and experimental models for studies on root canal preparation

It is the aim of this review to present a critical overview and summary on the contemporary possibilities, limitations and challenges of research related to root canal preparation. Frequently used research tools and contemporary research designs will be presented and discussed critically focussing on shortcomings and benefits with special regard to clinical relevance and scientific evidence. A plethora of experimental set-ups for assessing the shaping of root canals have been described in the endodontic literature using a considerable number of techniques and instruments. Nevertheless, it can be stated that scientific evidence demonstrating the clinical impact of many investigated topics is questionable or even missing. Instead of technical, radiographic and geometrical parameters, further research should focus on biological aspects and clinical evidence of the impact of root canal preparation on the outcome of root canal treatment.

Efficacy of different irrigation activation systems on bacterial extrusion

The purpose of this study was to evaluate the quantity of extruded bacteria following with EndoVac, EDDY, EndoActivator (EA) and standard needle irrigation (SNI). Ninety teeth with a single root and canal were included in this study. Fifteen teeth were selected as the negative control group to confirm sterilization. Seventy-five teeth were contaminated with Enterococcus faecalis (E. faecalis) for 4 weeks. Teeth were prepared and divided into five groups (n:15): EndoVac, EDDY, EA, SNI and positive control groups. The extruded bacteria were cultured for bacterial quantification. The counts of extruded bacteria were lower in the EndoVac group compared to the EDDY group (P˂ 0.05). The counts of extrusion bacteria were not different in EA and SNI groups compared to EDDY and EndoVac groups (P > 0.05). Within the limits of this study, EndoVac was found to be more reliable irrigation systems than EDDY in terms of the bacterial extrusion.

Comparative evaluation of apical bacterial extrusion following root canal instrumentation using different endodontic file systems: An in vitro study

Aim:

This study aims to evaluate the amount of apical extrusion of bacteria during root canal instrumentation using K3XF, Protaper Gold, Edge taper platinum, and Hyflex CM Rotary systems.

Materials and Methods:

Sixty freshly extracted maxillary incisors teeth collected in saline. Access cavity prepared and canals were made free of bacterial and pulp. The teeth were mounted on the bacteria collecting apparatus. Root canals were contaminated with the Fusobacterium Nucleatum (ATCC25586) and dried at 37°C for 24 h. In Group 1 (Control group): No instrumentation was done and biomechanical preparation done in all other groups with Group 2: Hand K-files, Group 3: Protaper gold, Group 4: K3XF, Group 5: Edge taper platinum, and Group 6: Hyflex CM rotary file systems. Then, the extrude was collected, and it is incubated in Mueller-Hinton agar for 24 h and the number of colony forming units were counted and statistical comparison was done using Kruskal–Wallis test and Mann–Whitney U test.

Results:

Hand K-files extruded more bacteria when compared to other four rotary systems, K3XF file system extruded least number of bacteria.

Conclusion:

All instrumentation techniques extruded intracanal bacteria apically. However, engine-driven nickel-titanium instruments extruded less bacteria than the manual technique. The K3XF rotary file system comparatively extruded less bacteria than other rotary file systems.

The effect of blue thermal treatment on endodontic instruments and apical debris extrusion during retreatment procedures

AIM

To determine the effect of blue thermal treatment on Reciproc (VDW, Munich, Germany) endodontic instruments and the amount of apically extruded debris during retreatment procedures.

METHODOLOGY

Thirty extracted mandibular molar teeth having mesial roots with a degree of curvature less than 20° and having an initial apical size equivalent to a size 10 K-file were selected. The mesial roots of the teeth were removed from the cementoenamel junction to obtain a 15-mm root length. The mesiobuccal canals were prepared to size F2 using the ProTaper Universal system (Dentsply Sirona, Ballaigues, Switzerland), filled with gutta-percha and 2Seal (VDW) using the lateral compaction technique and then randomly divided into two groups (n = 15). The root fillings were removed with one of the following instruments using a crown-down preparation technique: M-Wire Reciproc or Reciproc Blue (both VDW). Apically extruded debris was collected in pre-weighed Eppendorf tubes. The Eppendorf tubes were then stored in an incubator at 70 °C for five days to evaporate the distilled water. The data were analysed using the Mann-Whitney U test (P = 0.05).

RESULTS

Reciproc Blue (1.42 ± 0.4491 mg) extruded significantly less debris apically than M-Wire Reciproc (2.56 ± 1.0232 mg) (P < 0.05).

CONCLUSIONS

Blue thermal treatment of Reciproc instruments was associated with less debris extrusion during retreatment procedures.

Quantitative analysis of apically extruded bacteria following preparation of curved canals with three systems

This study compared the amount of apically extruded bacteria following preparation of curved root canals using two continuously rotating multifile and one reciprocating single-file systems. Mesiobuccal canals from maxillary molars were contaminated with Enterococcus faecalis and divided into three groups according to the instrumentation system: Reciproc (R25 instrument, 25/.08), BT-RaCe (10/.06, 35/.00 and 35/.04), and Mtwo (25/.06, 30/.05 and 35/.04). Apically extruded material was collected by a customized apparatus with 1.5% agarose gel covering the root apex to simulate the periradicular tissues. The extruded material was extracted from the gel and subjected to bacteriological culture for bacterial quantification. The three systems showed a high frequency of bacterial extrusion (>70%). There were no statistically significant differences in the counts of extruded bacteria between groups (P > 0.05). The incidence and amount of apical bacterial extrusion were similar between the three systems. The customized apparatus was effective in collecting apically extruded bacteria.

Quantitative Assessment of apically Extruded Bacteria using different Instrumentation Techniques and Preparation Taper

BACKGROUND

Cleaning and shaping of the pulp canal is one of the most important steps of endodontic therapy. Serious complications occur by the apical extrusion of bacteria during the instrumentation procedures. Both crown-down (CD) and full-length linear motion (FM) techniques are routinely used as a component of taper rotary instrument procedures for achievement of thorough cleaning and shaping of the pulp canal space. Hence, we aimed for this study to assess the change in the amount of apically extruded bacteria using CD and FM instrumentation techniques produced by differences in taper between the instruments used during biomechanical preparation of root canals.

MATERIALS AND METHODS

The present study included assessments of 132 extracted maxillary central incisor teeth. To achieve a uniform teeth length of 21 mm, the height of the tooth crown was reduced for preserving the coronal portion of teeth. A modified glass vial model was constructed for the estimation of amount of bacterial extrusion through the apical region. For filling of each pulp canal specimen, 20 mL of Enterococcus faecalis suspension was used followed by the use of a number 10 K-file for carrying the bacteria down the lengths of pulp canals. All the contaminated teeth specimens were divided into six study groups with groups I to III containing specimens prepared in the CD manner, while groups IV to VI contained specimens prepared in the FM manner. Six teeth were taken as negative control with three specimens with each technique, and another six specimens were taken as positive controls. Cultivable bacterial counts were determined by evaluating 100 mL saline solution from each vial followed by its inoculation on blood agar. All the colony-forming unit (CFU) values were log-transformed (base 10), and the results were analyzed by Statistical Package for the Social Sciences software.

RESULTS

A significantly lower quantity of CFU values was observed during CD instrumentation procedures with 0.02 files in comparison with all other study groups. However, while comparing both the instrumentation procedures when different taper files, other than 0.02 taper, were used for biomechanical preparation of root canal, nonsignificant results were obtained.

CONCLUSION

With 0.02 taper preparations, significantly less amount of extrusion of bacteria is associated when done with CD technique.

CLINICAL SIGNIFICANCE

No change in the amount of apical extrusion of bacteria will be seen by changing the type of instrumentation procedures. Amount of bacteria extruded can be minimized using 0.02 taper. Key words: Bacteria, Instrumentation, Taper.

Apical extrusion of Enterococcus faecalis in different canal geometries during the use of nickel titanium systems with different motion types

Background/purpose

Extrusion of intracanal bacteria leads to treatment failures. Compare the apical extrusion of intracanal bacteria (Enterococcus faecalis) during canal preparation with three different instrumentation techniques [RECIPROC, One Shape (OS), and Twisted-File Adaptive (TFA)] with different motion types.

Materials and methods

Ninety teeth with different canal morphologies were divided into three main groups, each including 30 teeth (10 mandibular incisors, 10 mandibular premolars, and 10 curved roots). Roots were resected until 13-mm working length was obtained and fixed to glass vials filled with brain-heart infusion broth. Each canal was filled with E. faecalis suspension. The three main groups were further grouped into three subgroups. Each group was further subgrouped into three, with each subgroup including 10 roots from each type of teeth (10 incisors/subgroup, 10 premolars/subgroup, and 10 curved canals/subgroup). These subgroups were prepared with one of RECIPROC, OS, or TFA. Bacterial colonies extruded into each vial were incubated in brain-heart infusion agar at 37°C for 5 days and counted using a colony counter as the number of colony-forming units per milliliter. Statistical analyses were performed using one-way analysis of variance, post hoc Tukey honest significant difference, and Kruskal-Wallis tests.

Results

Apically extruded bacteria were not statistically different from each other (P > 0.05). The amount of apically extruded bacteria was statistically similar for both different instruments in the same type of tooth (P > 0.05) and same instrument in different types of teeth (P > 0.05).

Conclusion

Neither the motion type of instrument nor the canal morphology affected the degree of bacterial extrusion.

CBCT Assessment of Root Dentine Removal by Gates-Glidden Drills and Two Engine-Driven Root Preparation Systems

Introduction:

The aim of this study was to compare the dentine removing efficacy of Gates-Glidden drills with hand files, ProTaper and OneShape single-instrument system using cone-beam computed tomography (CBCT).

Methods and Materials:

A total of 39 extracted bifurcated maxillary first premolars were divided into 3 groups (n=13) and were prepared using either Gates-Glidden drills and hand instruments, ProTaper and OneShape systems. Pre- and post-instrumentation CBCT images were obtained. The dentin thickness of canals was measured at furcation, and 1 and 2 mm from the furcation area in buccal, palatal, mesial and distal walls. Data were analyzed using one-way ANOVA test. Tukey’s post hoc tests were used for two-by-two comparisons.

Results:

Gates-Glidden drills with hand files removed significantly more (P<0.001) dentine than the engine-driven systems in all canal walls (buccal, palatal, mesial and distal). There were no significant differences between OneShape and ProTaper rotary systems (P>0.05).

Conclusion:

The total cervical dentine removal during canal instrumentation was significantly less with engine-driven file systems compared to Gates-Glidden drills. There were no significant differences between residual dentine thicknesses left between the various canal walls.

Evaluation of Apically Extruded Debris using Two Niti Systems Associated with Two İrrigation Techniques in Primary Teeth

PURPOSE

The aim of this study was to compare the effects of 2 NiTi file systems [Twisted File Adaptive (TFA) and Reciproc (RP)] and 2 irrigation techniques [Conventional needle irrigation (CNI) and Laser activated irrigation (LAI)] on the amount of apically extruded debris in primary maxillary molars.

STUDY DESIGN

Sixty extracted primary maxillary molars were randomly divided into 4 groups. The mesio-buccal roots of teeth in 4 groups were instrumented using TFA with LAI, RP with LAI, TFA with CNI and RP with CNI respectively. Debris extruded during instrumentation was collected into Eppendorf tubes and amounts were determined. The data were analyzed using two-way ANOVA test at 0.05 level of significance.

RESULTS

The results indicated all instrumentation and irrigation systems caused a measurable apical extrusion of debris. However, no statistically significant difference in debris extrusion was observed between irrigation techniques or instrumentation systems (P > 0.05). The total amount of debris extruded apically by LAI was greater than that by CNI.

CONCLUSIONS

All instrumentation and irrigation techniques caused debris extrusion. However, the optimal laser activation time and power settings should be investigated to ensure minimal extrusion of debris and irrigant due to cavitation and pressure during LAI in root canal treatment.

Effect of three different rotary instrumentation systems on postinstrumentation pain: A randomized clinical trial

Background:

Endodontic instrumentation is liable to cause some postinstrumentation pain (PIP). Rotary endodontic instruments differ in their design, metallurgy, surface treatment, etc.

Aim:

This randomized clinical trial aimed to assess the incidence of PIP after root canal instrumentation with three different rotary endodontic systems which differ in their design, namely, ProTaper, Mtwo, and K3.

Materials and Methods:

A total of 150 patients between the ages of 25 and 50 were chosen for the study. Teeth with asymptomatic irreversible pulpitis due to carious exposure were selected. The patients received local anesthesia by inferior alveolar nerve block. After preparing the access cavity, root canal instrumentation was done with one of the three instruments (n = 50) and closed dressing was given. PIP was assessed every 12 h for 5 days, and tenderness to percussion was analyzed at the end of 1, 3, and 7 days.

Statistical Analysis:

Mann–Whitney U-test to determine significant differences at P < 0.01.

Results:

The PIP and tenderness were less in Mtwo group when compared to ProTaper and K3 groups up to 84 h and 72 h respectively and statistically significant (P < 0.05). There was no statistically significant difference between ProTaper and K3 both in PIP and tenderness.

Conclusion:

Rotary endodontic instrumentation causes some degree of PIP and tenderness to percussion. Among the instruments used, Mtwo causes less PIP and tenderness when compared to ProTaper and K3, and there was no difference between ProTaper and K3.

Clinical Relevance:

PIP is highly subjective and may vary among different subjects. The apical (3 mm) taper of ProTaper was 0.08 followed by a smaller taper, whereas, the other two files were of a constant 0.06 taper, which means there could have been a greater apical extrusion and therefore more PIP. Despite, the mean of the age was similar, there could have been a difference in the size of the canal and therefore a difference in apical extrusion and PIP.

Apical Extrusion of Intracanal Bacteria following use of Two Engine-driven Instrumentation Techniques: An in vitro Study

AIM

The aim of the present study was to compare in vitro the amount of debris extruded apically from extracted teeth, using Twisted files and ProTaper rotary during two different instrumentation systems.

MATERIALS AND METHODS

Forty-five human single-rooted mandibular premolar teeth were randomly divided into three groups and contaminated with Enterococcus faecalis. The teeth in experimental groups were instrumented until reaching the working length with ProTaper rotary instruments and Twisted files with XSmart and XSmart Dual groups. Debris extruded from the apical foramen was collected into glass vials and the amount of bacteria was calculated. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests, with p = 0.05 as the level for statistical significance.

RESULTS

The XSmart Dual group extruded comparatively lesser bacteria compared to the XSmart group. Lesser amount of bacterial extrusion was seen when Twisted files were used compared to the ProTaper files (p < 0.05).

CONCLUSION

Under the circumstances of this in vitro study, it can be concluded that all instrumentation techniques produced measurable apical extrusion of debris. So, it is upon the practitioner to decide which system best fits their individual needs and their level of skill and experience that will provide the best possible endodontic care for our patients.

CLINICAL SIGNIFICANCE

The newer instrument designs, including noncutting tips, different cross sections, radial lands, and variable tapers, are better for the clinicians to improve working safety, to reduce the working time, and to create a greater flare within the preparations.

Apical extrusion of intracanal biofilm using ProTaper Gold, WaveOne Gold,Twisted File Adaptive, OneShape New Generation and K3XF

Objective:

To evaluate the bacterial extrusion during instrumentation with different nickel titanium (NiTi) engine-driven instruments.

Methods:

Ninety extracted single-canal human mandibular incisor teeth were inoculated with Enterococcus faecalis to obtain biofilm formation and were randomly divided to 6 groups (n=15). One group served as the control and was not instrumented; the other groups were prepared with ProTaper Gold (PTG; Dentsply Maillefer, Ballaigues, Switzerland), WaveOne Gold (WOG; Dentsply Maillefer), Twisted File Adaptive (TFA; SybronEndo, Orange, CA, USA), One Shape New Generation (OSNG; MicroMega, Besancon, France), and K3XF (SybronEndo) instruments. Bacteria extruded beyond the apical foramen were quantified in colony-forming units per milliliter. The number of colony-forming units in the remaining biofilm was determined for each sample. Data were analyzed using the one-way analysis of variance (ANOVA) and Tukey post-hoc tests.

Results:

All NiTi instruments resulted in different quantities of bacterial extrusion. The TFA group caused most bacterial extrusion (P<0.05). The PTG and WOG groups caused less bacterial extrusion than the OSNG and K3XF groups (P<0.05), but there was no statistically significant difference between the PTG and WOG groups (P>0.05).

Conclusion:

PTG and WOG are preferable system in terms of successful endodontic treatments. The amount of bacterial extrusion is associated with the metallurgy and design of the instrument used.

Reciproc versus Twisted file for root canal filling removal: assessment of apically extruded debris

PURPOSE

The aim of this study was to evaluate the amount of apically extruded debris during endodontic retreatment with different file systems.

MATERIALS AND METHODS

Sixty extracted human mandibular premolar teeth were used in this study. Root canals of the teeth were instrumented and filled before being randomly assigned to three groups. Guttapercha was removed using the Reciproc system, the Twisted File system (TF), and Hedström-files (H-file). Apically extruded debris was collected and dried in pre-weighed Eppendorf tubes. The amount of extruded debris was assessed with an electronic balance. Data were statistically analyzed using one-way ANOVA, Kruskal-Wallis, and Mann-Whitney U tests.

RESULTS

The Reciproc and TF systems extruded significantly less debris than the H-file (p<0.05). However, no significant difference was found between the Reciproc and TF systems.

CONCLUSION

All tested file systems caused apical extrusion of debris. Both the rotary file (TF) and the reciprocating single-file (Reciproc) systems were associated with less apical extrusion compared with the H-file.

In Vitro Comparison of Apically Extruded Debris during Root Canal Preparation of Mandibular Premolars with Manual and Rotary Instruments

Background and aims. During root canal preparation, debris extruded beyond the apical foramen may result in periapical inflammation and postoperative pain. To date no root canal preparation method has been developed that extrudes no periapical debris. The purpose of this study was to identify a system leading to minimal extrusion of debris from the apical foramen. The study was conducted to comparatively evaluate the amount of apical extrusion of debris during root canal preparation using hand ProTaper and GT rotary and RaCe rotary instruments using crown-down technique.

Materials and methods. Ninety freshly extracted human single-rooted mandibular premolars were equally assigned to three groups (n=30). The root canals were instrumented using hand ProTaper, GT rotary and RaCe rotary systems. Debris and irrigant extruded from the apical foramen were collected into vials. The mean weight of the remaining debris was calculated for each group and subjected to statistical analysis.

Results. ANOVA was used to compare the mean dry weights of the debris extruded in the three groups, followedby post hoc Tukey tests for multiple comparisons the between groups. Highly significant differences were found in the amount of debris extruded among all the groups (P<0.001). The ProTaper group exhibited the highest mean debris weight (0.8293±0.05433 mg) and the RaCe system exhibited the lowest mean debris weight (0.1280±0.01606 mg).

Conclusion. All the systems tested resulted in apical extrusion of debris. However, the hand ProTaper files extruded a significantly higher amount of debris than GT and RaCe systems.

A Comparison of Apical Bacterial Extrusion in Manual, ProTaper Rotary, and One Shape Rotary Instrumentation Techniques

INTRODUCTION

Apical extrusion of irrigants and debris is an inherent limitation associated with cleaning and shaping of root canals and has been studied extensively because of its clinical relevance as a cause of flare-ups. Many factors affect the amount of extruded intracanal materials. The purpose of this study was to assess the bacterial extrusion by using manual, multiple-file continuous rotary system (ProTaper) and single-file continuous rotary system (One Shape).

METHODS

Forty-two human mandibular premolars were inoculated with Enterococcus faecalis by using a bacterial extrusion model. The teeth were divided into 3 experimental groups (n = 12) and 1 control group (n = 6). The root canals of experimental groups were instrumented according to the manufacturers' instructions by using manual technique, ProTaper rotary system, or One Shape rotary system. Sterilized saline was used as an irrigant, and bacterial extrusion was quantified as colony-forming units/milliliter. The results obtained were statistically analyzed by using one-way analysis of variance for intergroup comparison and post hoc Tukey test for pair-wise comparison. The level for accepting statistical significance was set at P < .05.

RESULTS

All the instrumentation techniques resulted in bacterial extrusion, with manual step-back technique exhibiting significantly more bacterial extrusion than the engine-driven systems. Of the 2 engine-driven systems, ProTaper rotary extruded significantly more bacteria than One Shape rotary system (P < .05).

CONCLUSIONS

The engine-driven nickel-titanium systems were associated with less apical extrusion. The instrument design may play a role in amount of extrusion.

Comparison of apical and coronal extrusions using reciprocating and rotary instrumentation systems

Background

The aim of this study was to compare the apical and coronal extrusions by using two reciprocating and two rotary instrumentation systems.

Methods

Eighty extracted human single-rooted anterior teeth were randomly assigned to four groups. Four different root canal instrumentation systems were used according to the manufacturers instructions, including two reciprocating single-file systems, Reciproc and WaveOne, and two full-sequence rotary BLX and ProTaper instruments. Debris collected from the coronal by the instruments and apical extrusions were quantified respectively. After drying the collections, the mean weight of debris collected from apical and coronal extrusions was assessed using an electronic balance and analyzed using the Kruskal–Wallis H and Mann–Whitney U tests.

Results

Statistically significant differences in the apical extrusion were observed among the four groups. Reciproc and WaveOne instruments produced significantly less debris than BLX and ProTaper instruments (P < 0.05).

Conclusions

All of the systems produced apical extrusion of debris. However, reciprocating single-file systems produced less apical extrusion than full-sequence rotary systems. No relationship was observed between apical and coronal extrusions.

Comparison of apically extruded debris after root canal instrumentation using Reciproc(®) instruments with various kinematics

AIM

To assess the amount of apically extruded debris using Reciproc(®) instruments with different kinematics (150° counter clockwise [CCW]-30° clockwise [CW], 270° CCW-30° CW, 360° CCW-30° CW and continuous rotation).

METHODOLOGY

Forty-eight maxillary central incisors were selected and assigned to four root canal shaping groups as follows (n = 12): 150° CCW-30° CW, 270° CCW-30° CW, 360° CCW-30° CW and continuous rotation. Reciproc R25 and R50(®) instruments were used in all groups. Apically extruded debris was collected and dried in preweighed Eppendorf tubes. The weight of extruded debris was assessed with an electronic balance. The data were analysed with one way analysis of variance and LSD post hoc tests (P = 0.05).

RESULTS

The 150° CCW-30° CW and 270° CCW-30° CW reciprocating motions extruded significantly less debris than continuous rotation (P < 0.05). However, no significant differences were found between the 360° CCW and 30° CW reciprocating motion and the continuous rotation (P > 0.05).

CONCLUSIONS

All instrument movements were associated with apically extruded debris. However, the 150° CCW-30° CW and 270° CCW-30° CW reciprocating motions were associated with less extrusion than continuous rotation.

The effect of single-file reciprocating systems on Substance P and Calcitonin gene-related peptide expression in human periodontal ligament

AIM

To quantify the effect of two single-file reciprocating root canal preparation systems on Substance P (SP) and Calcitonin gene-related peptide (CGRP) expression in healthy human periodontal ligament (PDL).

METHODOLOGY

Forty PDL samples were obtained from healthy premolars where extraction was indicated for orthodontic reasons. Prior to extraction, 20 of these premolars were divided equally in two groups, and then, root canals were prepared using one of two different single-file systems: WaveOne and Reciproc. Ten premolars were prepared with hand files and served as a positive control group. The remaining 10 premolars where extracted without treatment and served as a negative control group. All PDL samples were processed, and SP and CGRP were measured by radioimmunoassay.

RESULTS

Greater SP and CGRP expression were found in the hand instrumentation group (1.220 pmol SP and 0.084 pmol CGRP per mg of PDL), followed by the WaveOne group (0.908 pmol SP and 0.046 pmol CGRP per mg of PDL) and the Reciproc group (0.511 pmol SP and 0.022 pmol CGRP per mg of PDL). The lower SP and CGRP values were associated with the intact control group (0.453 pmol SP and 0.018 pmol CGRP per mg of PDL). The Kruskal-Wallis test revealed significant differences between groups (P < 0.001). Post hoc Tukey HSD tests revealed significant differences in SP and CGRP expression between intact teeth in the control group and all the other groups (P < 0.001) except with the Reciproc group (P = 0.165 and P = 0.42 for SP and CGRP, respectively). Hand instrumentation was associated with significant differences with all the other groups (P < 0.001). Differences between the WaveOne and Reciproc groups were also significant (P < 0.001).

CONCLUSION

Substance P and CGRP expression in PDL cells increased when teeth were prepared with WaveOne as well as with hand instrumentation. Reciproc maintained SP and CGRP levels in line with the negative control group.

Comparative evaluation of apical extrusion of bacteria using hand and rotary systems : An in vitro study

Aim:

To evaluate the bacteria extruded apically during root canal preparation using two hand and rotary instrumentation techniques.

Materials and Methods:

Eighty freshly extracted mandibular premolars were mounted in bacteria collection apparatus. Root canals were contaminated with the pure culture of Enterococcus fecalis (ATCC 29212) and dried at 37°C for 24 h. Bacteria extruded were collected, incubated in brain heart infusion agar for 24 h at 36°C and the colony forming units (CFU) were counted.

Statistical Analysis:

The mean number of colony forming units were calculated by One-way ANOVA and comparison between the groups made by multiple comparison (Dunnet D) test.

Results:

The step-back technique extruded highest number of bacteria in comparison to other hand and rotary Ni–Ti systems.

Conclusion:

Under the limitation of this study all hand and rotary instrumentation techniques extruded bacteria. Among all the instrumentation techniques step-back technique extruded more number of bacteria and K-3 system the least. Further in vivo research in this direction could provide more insight into the biologic factors associated and focus on bacterial species that essentially play a major role in post instrumentation flare-ups.

The effect of three different rotary instrumentation systems on substance P and calcitonin gene-related peptide expression in human periodontal ligament

INTRODUCTION

The purpose of this study was to quantify the effect of three different rotary root canal preparation systems on substance P and calcitonin gene-related peptide expression in healthy human periodontal ligament.

METHODS

Fifty periodontal ligament samples were obtained from healthy premolars in which extraction was indicated for orthodontic reasons. Before extraction, 40 of these premolars were equally divided into four groups, and root canals were prepared using four different systems: the ProTaper Universal rotary system, the RaCe rotary system, the Mtwo rotary system, and the hand instrumentation technique. The remaining 10 healthy premolars that were extracted without treatment served as a negative control group. All periodontal ligament samples were processed, and SP and CGRP were measured by radioimmunoassay.

RESULTS

Greater SP and CGRP expression were found in the ProTaper Universal group followed by the hand instrumentation group, the RaCe, and the Mtwo groups. The lower SP and CGRP values were for the negative control group. The Kruskal-Wallis test showed statistically significant differences between groups (p < 0.0001). Post hoc Least Significant Difference (LSD) tests showed statistically significant differences in SP and CGRP expression between the negative control group and all the other groups except the Mtwo group. Hand instrumentation also showed statistically significant differences with all the other groups, except the ProTaper Universal group. Differences between the three rotary systems were also statistically significant.

CONCLUSION

SP and CGRP expression in periodontal ligament increases when teeth are prepared with ProTaper Universal and RaCe rotary instrumentation systems as well as with hand instrumentation. Mtwo maintains SP and CGRP levels.