Apical extrusion of debris and irrigants using two hand and three engine-driven instrumentation techniques

Comparison of sodium hypochlorite extrusion by five irrigation systems using an artificial root socket model and a quantitative chemical method

OBJECTIVES

This is to compare the volumes of irrigant apically extruded by five irrigation systems in an artificial socket model simulating clinical conditions.

MATERIALS AND METHODS

Twenty extracted human single-rooted teeth were enlarged to size 40/04 and then embedded in silicone impression material. The root canal space was irrigated with nominal 3% sodium hypochlorite (NaOCl) using standard needle irrigation (SNI) with a 30-gauge notched needle, EndoActivator (EA), XP Endo Finisher (XP Endo), EndoVac (EV), and photon-induced photoacoustic streaming (PIPS). Extruded NaOCl was collected, reacted with taurine to form taurine-monochloramine, and absorbance of taurine-monochloramine was measured at 252 nm using a spectrophotometer. The five irrigation systems were compared with repeated measures ANOVA and pairwise comparisons.

RESULTS

The EV group had very low extrusion (mean ± SD = 0.12 ± 0.2 μL) and differed significantly from the other four groups (P ≤ 0.001). Larger volumes of irrigant were extruded in the other irrigation groups. There were no significant differences in the extruded volumes among the SNI (7.4 ± 3.4 μL), EA (7.0 ± 6.1 μL), and XP Endo (7.8 ± 4.1 μL) groups (P = 1). The PIPS group had the highest mean extruded volume (12.9 ± 6.8 μL) and differed significantly from SNI (P = 0.030), EV (P < 0.0005), and EA (P = 0.02), but not XP Endo (P = 0.154).

CONCLUSION

Under the in vitro conditions of this study, irrigant extrusion appears unavoidable unless negative pressure irrigation such as EV is used. PIPS extrudes more irrigant than other systems, while SNI, EA, and XP Endo extrude similar volumes of irrigant.

CLINICAL RELEVANCE

The findings help clinicians select the optimal irrigation system to avoid irrigant extrusion.

Apical extrusion of debris during the preparation of oval root canals: a comparative study between a full-sequence SAF system and a rotary file system supplemented by XP-endo finisher file

OBJECTIVES

The purpose of this study was to assess the amount of apically extruded debris during the preparation of oval canals with either a rotary file system supplemented by the XP-endo Finisher file or a full-sequence self-adjusting file (SAF) system.

MATERIALS AND METHODS

Sixty mandibular incisors were randomly assigned to two groups: group A: stage 1-glide path preparation with Pre-SAF instruments. Stage 2-cleaning and shaping with SAF. Group B: stage 1-glide path preparation with ProGlider file. Stage 2-cleaning and shaping with ProTaper Next system. Stage 3-Final cleaning with XP-endo Finisher file. The debris extruded during each of the stages was collected, and the debris weights were compared between the groups and between the stages within the groups using t tests with a significance level set at P < 0.05.

RESULTS

The complete procedure for group B resulted in significantly more extruded debris compared to group A. There was no significant difference between the stages in group A, while there was a significant difference between stage 2 and stages 1 and 3 in group B, but no significant difference between stages 1 and 3.

CONCLUSIONS

Both instrumentation protocols resulted in extruded debris. Rotary file followed by XP-endo Finisher file extruded significantly more debris than a full-sequence SAF system. Each stage, in either procedure, had its own contribution to the extrusion of debris.

CLINICAL RELEVANCE

Final preparation with XP-endo Finisher file contributes to the total amount of extruded debris, but the clinical relevance of the relative difference in the amount of apically extruded debris remains unclear.

Apical Extrusion of Debris and Irrigants Using Different Irrigation Needles

This study evaluated the influence of irrigation tip, root canal curvature and final apical diameter on periapical debris and irrigant extrusion during root canal instrumentation. After being classified as mildly or moderately curved, the mesiobuccal root canals of 90 human molars were instrumented. The teeth were allocated into three groups according to the used needle type: a flat open-end needle (Group 1), a side-vented needle (Group 2) or a double side-vented needle (Group 3). The amount of extruded material after instrumentation was calculated for each group. The differences in irrigant and debris extrusion between the experimental groups were analyzed with the Mann-Whitney U test. Irrigation tips and final instrument diameter differences were analyzed with the Kruskal-Wallis test. Multiple groups were compared using the Mann-Whitney U-test with a Bonferroni correction at α=0.05. The amount of extruded material from the double side-vented needle was significantly less than the open-ended flat needle (p=0.008), but there was no difference compared to the side-vented needle (p=0.929). The results showed no effect of root curvature and final apical diameter on the amount of irrigant and debris extrusion (p>0.05). The double side-vented needles generated the least material extrusion to the periapical tissues. Irrigation needle type had the greatest influence on periapical irrigant and debris extrusion and the double side-vented needles may be safely used during endodontic therapy.

In vitro Comparison of Apical Debris Extrusion Using Rotary and Reciprocating Systems in Severely Curved Root Canals

Introduction:

The aim of this in vitro study was to compare the amount of apically extruded debris after root canal preparation using rotary and reciprocating systems in severely curved root canals.

Methods and Materials:

Thirty six extracted human mandibular first molars with 25-35^° curvature in their mesiobuccal (MB) canal (according to Schneider’s method) were cleaned and shaped with ProTaper and WaveOne systems. The extruded debris was collected and their net weight was calculated. To compare the efficiency of the two systems, the operation time was also measured. The data were analyzed with t-test.

Results:

The amount of extruded debris in WaveOne group was significantly greater in comparison with ProTaper group (26%). The operating time for ProTaper was however, significantly longer than WaveOne.

Conclusion:

Both root preparation systems caused some degree of debris extrusion through the apical foramen. However, this amount was greater in WaveOne instruments.

Less extrusion debris during the retreatment of curved canals using twisted files with higher rotational speeds: an ex vivo study

BACKGROUND

Debris extrusion from the apical foramen can be problematic in severely curved canals. This study aimed to assess the use of Twisted Files (TF) at different rotational speeds during retreatment, compared with manual technique using Triple-Flex Files (TFF).

METHODS

Forty-eight mesiobuccal root canals were randomized to four groups (n = 12 per group). In groups A, B, and C, gutta-percha was removed using TF at 500, 1000, and 1500 rpm, respectively, while it was removed using TFF in group D. Apical debris was collected in a pre-weighed centrifuge tube. The weight of dry debris was assessed by comparing the pre- and post-instrumentation weight for each group.

RESULTS

Instrumentation in group D (0.69 ± 0.04 mg) extruded significantly more debris than any of the TF groups (A: 0.54 ± 0.05 mg; B: 0.48 ± 0.04 mg; C: 0.42 ± 0.03 mg; all P < 0.001). In addition, increasing the rotational speed of TF decreased the amount of extruded debris (A vs. B: P = 0.006; B vs. C: P < 0.001; A vs. C: P < 0.001).

CONCLUSIONS

TF at 1500 rpm produced less apical extrusion debris than other TF operating speeds and TFF.

Comparative evaluation of apically extruded debris during root canal instrumentation using two Ni-Ti single file rotary systems: An in vitro study

BACKGROUND

Apical extrusion of debris during instrumentation is detrimental to the patient.

AIM

The aim of this study was to evaluate the apical extrusion of debris during root canal instrumentation using two single file rotary Ni-Ti systems.

MATERIALS AND METHODS

Thirty freshly extracted mandibular premolars with straight roots were sterilized and divided into two groups instrumented using: One Shape rotary Ni-Ti system with Endoflare orifice shaper (Group 1) and Neo-Niti rotary Ni-Ti system with C1 orifice shaper (Group 2). Preweighed Eppendorf tubes fitted for each tooth before instrumentation. During instrumentation, 1 mL of distilled water with a 30-gauge needle was used to irrigate after every instrument. Tips of the tooth were irrigated with 2 ml distilled water after removal from Eppendorf tubes. The total volume of irrigant in each group was the same 8 ml. All tubes were incubated at 68°C for 15 days and subsequently weighed. The difference between pre- and post-debris weights was calculated, and statistical analysis was performed using independent t-test and level of significance was set at 0.05.

RESULTS

The difference between pre- and post-weights was significantly greater for the One Shape system.

CONCLUSIONS

The Neolix Niti single file was associated with less extrusion compared to One Shape single file system.

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.

Fracture resistance of dental nickel-titanium rotary instruments with novel surface treatment: Thin film metallic glass coating

BACKGROUND/PURPOSE

Dental nickel-titanium (NiTi) rotary instruments are widely used in endodontic therapy because they are efficient with a higher success rate. However, an unpredictable fracture of instruments may happen due to the surface characteristics of imperfection (or irregularity). This study assessed whether a novel surface treatment could increase fatigue fracture resistance of dental NiTi rotary instruments.

METHODS

A 200- or 500-nm thick Ti-zirconium-boron (Ti-Zr-B) thin film metallic glass was deposited on ProTaper Universal F2 files using a physical vapor deposition process. The characteristics of coating were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. In cyclic fatigue tests, the files were performed in a simulated root canal (radius=5 mm, angulation=60°) under a rotating speed of 300rpm. The fatigue fractured cross sections of the files were analyzed with their fractographic performances through scanning electron microscopy images.

RESULTS

The amorphous structure of the Ti-Zr-B coating was confirmed by transmission electron microscopy and X-ray diffractometry. The surface of treated files presented smooth morphologies without grinding irregularity. For the 200- and 500-nm surface treatment groups, the coated files exhibited higher resistance of cyclic fatigue than untreated files. In fractographic analysis, treated files showed significantly larger crack-initiation zone; however, no significant differences in the areas of fatigue propagation and catastrophic fracture were found compared to untreated files.

CONCLUSION

The novel surface treatment of Ti-Zr-B thin film metallic glass on dental NiTi rotary files can effectively improve the fatigue fracture resistance by offering a smooth coated surface with amorphous microstructure.

Cyclic fatigue behavior of nickel-titanium dental rotary files in clinical simulated root canals

BACKGROUND/PURPOSE

Dental rotary instruments can be applied in multiple conditions of canals, but unpredictable fatigue fracture may happen. This study evaluated the fatigue lives of two batches of nickel-titanium (NiTi) dental rotary files operating in clinically simulated root canals.

METHODS

Single-step cyclic fatigue tests were carried out to assess the performance of two batches of NiTi files (ProTaper and ProFile) in nine combinations of simulated canals (cylinder radii 5 mm, 7.5 mm, and 10 mm, and insertion angles 20°, 40°, and 60°). Two-step cyclic fatigue tests were carried out in simulated root canals with the same radius by using the following two sets of insertion angles: (20°, 40°), (20°, 60°), (40°, 20°), and (60°, 20°). Fracture surfaces were observed by scanning electron microscopy.

RESULTS

The single-step cyclic fatigue results showed that cyclic fatigue lives of the files decreased with increasing insertion angles or decreasing cylinder radius. The ProFile #25 .04 file was more fatigue resistant than the ProTaper F2 file. In two-step cyclic fatigue tests, the total fatigue lives were usually more than 100% when the files operated at a lower strain and then at a higher strain. By scanning electron microscopy, a larger area of fatigue striation corresponded to a longer fatigue life.

CONCLUSION

Cyclic fatigue life can be influenced by the strains and geometries of files. The fatigue life was prolonged when the files operated at a lower strain and then at a higher strain. However, the fatigue life was shortened if the loading sequence was reversed.

Comparison of apical debris extrusion of two rotary systems and one reciprocating system

BACKGROUND

Postoperative inflammation and endodontic failure occur due to apical extrusion of debris.

AIM

To evaluate the amount of apically extruded debris after preparation of straight root canals in extracted human teeth using three rotary systems.

MATERIALS AND METHODS

Sixty single-rooted human teeth with single root canal and apical foramen were selected and randomly divided into three experimental groups (n = 20) according to the rotary system used: Group 1 - ProTaper, Group 2 - Revo-S, Group 3 - WaveOne. Apical enlargement was done up to size 40/0.06 for Groups 1 and 2 and 40/0.08 for Group 3. For debris collection, each tooth was held in a preweighed Eppendorf tube fixed inside a glass vial through rubber plug. After instrumentation, each tooth was separated from the Eppendorf tube and the debris adhering to the root surface was collected by washing the root with 1 mL of bi-distilled water and incubated at 70°C for 5 days. The dry weight of extruded debris was weighed in an electronic balance.

STATISTICAL ANALYSIS

The mean weights of extruded debris were statistically analyzed using GraphPad prism version 6 and the intergroup comparison was done using unpaired t-test.

RESULTS

There was a statistically significant difference in the mean debris score among all the three groups - ProTaper (0.00065 g), Revo-S (0.00045 g) and WaveOne (0.00089 g).

CONCLUSION

Revo-S system was associated with significantly less debris extrusion compared with ProTaper or WaveOne.

Postoperative endodontic pain of three different instrumentation techniques in asymptomatic necrotic mandibular molars with periapical lesion: a prospective, randomized, double-blind clinical trial

OBJECTIVES

The purpose of this prospective, randomized, double-blind study was to compare postoperative pain of root canal treatment in patients with asymptomatic mandibular molar teeth with necrotic pulp and periapical lesion using three different instrumentation techniques: hand, multi-file rotary (ProTaper Universal), and reciprocating single-file (Wave-One) instrumentation techniques.

MATERIALS AND METHODS

Ninety-six patients who fulfilled specific inclusion criteria were assigned to three groups according to the root canal instrumentation technique used: Hand (G1), ProTaper Universal (G2), and Wave-One (G3). One-visit root canal treatment was carried out, and the severity of the postoperative pain was assessed by the Heft-Parker visual analogue scale 6, 12, 18, 24, 48, and 72 h after treatment. Data were analyzed by Kruskal-Wallis, χ ², Cochrane Q, one-way ANOVA, and Spearman's correlation analyses (α = 0.05).

RESULTS

The patients in group 3 reported significantly lower postoperative pain levels at 6, 12, and 18 h compared with the patients in the two other groups (P < .05). In addition, the patients in group 2 reported significantly lower postoperative pain levels at 6 and 12 h compared with the patients in group 1 (P < .05). There were no significant differences in postoperative pain between the three groups at other time intervals (P > .05). The analgesic consumption was significantly higher in group 1 (P < .05), but no difference was seen between the two other groups (P > .05).

CLINICAL RELEVANCE

Postoperative pain was significantly lower in patients undergoing root canal instrumentation with the Wave-One file compared with the ProTaper Universal and hand files.

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.

Evaluation of Apically Extruded Debris and Irrigant Produced by Different Nickel-Titanium Instrument Systems in Primary Teeth

AIM

The purpose of this study was to determine the amount of extruded debris and irrigant associated with different single-file systems and one multiple-file system.

MATERIALS AND METHODS

Forty-five newly extracted single rooted primary canine teeth were used in this study. The root canals were instrumented using the reciprocating single-file system, the single-file rotary system and the multiple-file rotary system. A 10(-6) precision micro-balance was used to calculate the amount of extruded debris and irrigant. The incubation period was set as 15 days at 37°C to obtain dry debris. The preparation time for instrumentation was also recorded. The data were statistically analyzed by Manova and Bonferroni adjustment.

RESULTS

Considering the apically extruded debris, while there was statistically significant difference between Reciproc and OneShape groups (p < 0.05), no statistically significant difference was found among the other groups (p > 0.05). In terms of irrigation solution, although significant difference was obtained between the Reciproc and other two groups (p < 0.05), no statistically significant difference was obtained between the two rotary instruments (p > 0.05). Instrumentation was significantly faster using Reciproc than with all other instrument (p < 0.05).

CONCLUSION

All systems caused apical debris and irrigant extrusion. Full-sequences rotary instrumentation systems may be preferable for preparation primary teeth.

CLINICAL SIGNIFICANCE

This is the first study carrying out to compare both apical debris and irrigation solution extrusion with reciprocal and rotary single-file systems with other preparation systems in primary teeth.

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 large apical preparations by full-sequence rotary and single-file reciprocating systems

AIM

To evaluate the amount of apically extruded debris produced by ProTaper Universal (PTU), ProTaper Next (PTN), WaveOne (WO) and Reciproc (R) systems after large apical preparations.

METHODOLOGY

Sixty mandibular premolars with a single canal were selected and randomly assigned into 4 groups (n = 15) according to the system used for root canal preparation: PTU, PTN, WO and R groups. Canal preparations were performed up to size 40 in each group. Distilled water was used as an irrigant, and the apically extruded debris from each tooth was collected in pre-weighted glass vials and dried. The average weight of debris was assessed using a microbalance, and the data were analysed statistically using one-way analysis of variance and the post hoc Tukey multiple comparison test (α = 0.05).

RESULTS

The PTU system was associated with significantly more debris than the other systems (P < 0.05). No significant differences were found between PTN, WO and R systems (P > 0.05).

CONCLUSIONS

All systems were associated with apical debris extrusion when canals were prepared to a large apical size. The PTU system was associated with more debris extrusion.

Apical Extrusion of Debris after Canal Preparation with Hand-Files Used Manually or Installed on Reciprocating Air-Driven Handpiece in Straight and Curved Canals

Introduction:

Apical debris extrusion (DE) subsequent to root canal instrumentation, is one of the most important causes of endodontic flare-ups. The aim of this study was to compare the amount of DE after root canal instrumentation using nickel-titanium (NiTi) hand files with step-back manual technique or installed on reciprocating handpiece.

Methods and Materials:

This study was conducted on mesiobuccal (MB) roots of extracted maxillary first molars (n=20) and roots of mandibular premolars (n=20) that were randomly divided into two groups (n=20) according to the armamentarium used for canal preparation (air-driven reciprocating handpiece or hand instrumentation). In each group, the MB and premolar roots were prepared with the main apical sizes of 35 and 40, respectively. The extruded debris were collected and weighed. Finally, the mean dry weights were compared using ANOVA and t-test, and Tukey’s Multiple Comparisons Procedures were used to determine the significant differences in amounts of DE. The level of significance was set at 0.05.

Results:

Regardless of the type of teeth, the mean values of DE, were significantly lower in the handpiece group (P<0.0001). In addition, significantly lower amounts of DE was observed in premolars in similar group (P<0.001). However, this difference was not significant in MB roots of molars (P=0.20).

Conclusion:

Root canal preparation with reciprocating handpiece can lead to significantly lower debris extrusion than the manual step-back technique. In handpiece-prepared canals, the amount of extruded debris was significantly lower in premolar teeth.

Evaluation of 4 Different Irrigating Systems for Apical Extrusion of Sodium Hypochlorite

INTRODUCTION

The aim of this study was to evaluate NaOCl apical extrusion by using negative apical pressure (EndoVac), sonic agitation (EndoActivator), side-vented needle (Max-i-Probe), and photon induced photoacoustic streaming (PIPS 10 mJ and PIPS 20 mJ) laser irrigation in an in vitro gel model.

METHODS

Extracted mandibular and maxillary central incisors (n = 18) were prepared to size 35/.04 and 55/.04, respectively. Teeth were mounted in transparent containers with clear acrylic and suspended in a color-changing pH-sensitive gel, creating a closed system. By using a crossover design, each tooth was sequentially irrigated by using 6% NaOCl with each device following manufacturers' recommendations. Each tooth served as its own control. Pre-irrigation and post-irrigation buccal and proximal view photographs served to measure the longest distance of extrusion and were analyzed with ImageJ software. Mean results were analyzed by using Kruskal-Wallis and Dunn post hoc test (P < .05).

RESULTS

There were no significant differences between EndoVac, EndoActivator, and the passive extrusion groups. The EndoVac and EndoActivator groups produced significantly less extrusion than PIPS irrigation. Max-i-Probe extrusion results were more variable than those of EndoActivator but had no significant difference. Across all irrigation systems, there were no significant differences with respect to apical preparation size.

CONCLUSIONS

Under the in vitro conditions of this study, no difference was found between the 10 mJ and 20 mJ PIPS laser groups. EndoVac demonstrated significantly less potential for apical extrusion than PIPS and Max-i-Probe, whereas apical preparation size did not significantly affect extrusion of irrigant. The potential for apical extrusion of endodontic irrigants should be a consideration when selecting a system for final irrigation.

The effects of different nickel-titanium instruments on dentinal microcrack formations during root canal preparation

OBJECTIVE

The aim of the present study was to investigate the incidence of dentinal microcracks caused by different preparation techniques.

MATERIALS AND METHODS

120 extracted human mandibular incisor teeth were divided into five experimental groups and one control group (n = 20): Group 1: Hand preparation with balanced force technique up to #25 K-file. Group 2: Preparation with only ProTaper F2 instrument in a reciprocating movement. Group 3: Preparation with Reciproc R25 instrument in a reciprocating movement. Group 4: Preparation with ProTaper instruments up to F2 instrument. Group 5: Preparation with ProTaper Next instruments up to X2 instrument. No procedure was applied to control group. The roots were sectioned horizontally at 3, 6 and 9 mm from the apex and examined. Absence or presence of dentinal microcracks was noted.

RESULTS

The Chi-square test was performed to compare the appearance of cracked roots between all groups. There were no significant differences among the groups (P > 0.05).

CONCLUSIONS

In conclusion, except the hand file and control group, all experimental groups showed microcrack formations.

Assessment of apically extruded debris and irrigant produced by different nickel-titanium instrument systems

The aim of this study was to evaluate the preparation time and the amounts of apically extruded debris and irrigant using different nickel-titanium instrumentation systems. Forty-five extracted single-rooted mandibular premolar teeth were selected and divided into three groups. The root canals were instrumented according to the manufacturers' instructions, using a reciprocating single-file system, a single-file rotary system and a multiple-file rotary system. Bidistilled water was used as the irrigant solution. The apically extruded debris and irrigant were collected into preweighed Eppendorf tubes. The amounts of extruded debris and irrigant were assessed with a precision micro-balance. The Eppendorf tubes were incubated at 37°C for 15 days. After the incubation period, they were weighed again to assess the debris extrusion. The time required to prepare the canals was also recorded. The results were statistically analyzed using MANOVA and Bonferroni's adjustment. Considering the apically extruded debris and irrigant, there were no statistically significant differences among the groups (p > 0.05). The Reciproc group produced the highest debris (0.000632 ± 0.000162 gr) and irrigant (0.844587 ± 0.437814 ml) extrusion values. While the least extruded debris was observed with OneShape (0,000431 ± 0,000171 gr), the least extruded irrigant was observed with ProTaper system (0.564147 ± 0.370596 ml). Instrumentation was faster using the Reciproc than the other two instruments (70.27 ± 13.38 s) (p < 0.05). All of the instrumentation systems used in this study produced apical debris and irrigant extrusion. The reciprocating single-file system tended to produce more debris and irrigant extrusion, compared with the rotary systems. Considering the preparation time, the single-file systems appeared to be advantageous due to their working time.

Comparative evaluation of apically extruded debris during root canal preparation using ProTaper™, Hyflex™ and Waveone™ rotary systems

BACKGROUND AND AIMS

Extrusion of any debris during endodontic treatment may potentially cause post-operative complications such as flare-ups. The purpose of this in vitro study was to assess the amount of apically extruded debris during the root canal preparation using rotary and reciprocating nickel-titanium instrumentation systems.

MATERIALS AND METHODS

In this study, 60 human mandibular first premolars were randomly assigned to 3 groups (n = 20 teeth/group). The root canals were instrumented according to the manufacturers' instructions using the Reciprocating single-file system WaveOne™ (Dentsply Maillefer, Ballaigues, Switzerland) and full-sequence rotary Hyflex CM™ (Coltene Whaledent, Allstetten, Switzerland) and ProTaper™ (Dentsply Maillefer, Ballaigues, Switzerland) instruments. The canals were then irrigated using bidistilled water. The debris that was extruded apically was collected in preweighed eppendorf tubes and assessed with an electronic balance and compared.

STATISTICAL ANALYSIS USED

The debris extrusion was compared and statistically analyzed using analysis of variance and the post hoc Student-Newman-Keuls test.

RESULTS

The WaveOne™ and ProTaper™ rotary instruments produced significantly more debris compared with Hyflex CM™ rotary instruments (P < 0.05).

CONCLUSIONS

Under the conditions of this study, all systems that were used resulted in extrusion of apical debris. Full-sequence rotary instrumentation was associated with less debris extrusion compared with the use of reciprocating single-file systems.

Quantitative evaluation of apical extrusion of debris and irrigants using four rotary instrumentation systems: an in vitro study

CLINICAL SIGNIFICANCE

The apical extrusion of infected debris may have the potential to disrupt the balance between microbial aggression and host defense, resulting in incidents of acute inflammation. During preparation, irrigants and debris, such as bacteria, dentin filings and necrotic tissue may be extruded into the periradicular region leading to periapical inflammation and postoperative flare ups. Using an instrumentation technique that minimizes apical extrusion would be beneficial to both the practitioner and patient. The purpose of the study was to evaluate the weight of debris and volume of irrigant extruded apically from extracted teeth in vitro after endodontic instrumentation using four different rotary root canal instrumentation systems.

MATERIALS AND METHODS

Four groups of each 20 extracted mandibular premolars were instrumented using one of the four systems: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland)), Hero-shaper (MicroMega, Besancon, France), RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and K3 (SybronEndo, West Collins, CA). Debris and irrigant extruded from the apical foramen during instrumentation were collected in preweighed test tubes. Volume of irrigant extruded was noted. The containers were stored in incubator at 70° for two days to evaporate the moisture. Weight of dry debris was noted.

STATISTICAL ANALYSIS

Data was analyzed using Kruskall-Wallis and Mann-Whitney U test at a significance of 0.001.

RESULTS

The results indicated that all of the instrumentation systems tested caused measurable apical extrusion of debris and irrigants. Higher extrusion was observed with Protaper system which was statistically significant with Hero-Shaper, RaCe and K3 systems. There were no statistical differences between Hero-shaper, K3 and RaCe systems (p < 0.05).

CONCLUSION

All instrumentation techniques apically extruded debris and irrigant. However, Hero-shaper, K3 and RaCe systems produced less extruded debris and irrigant than the Protaper system.

Effect of Patency File on Transportation and Curve Straightening in Canal Preparation with ProTaper System

The aim of this ex vivo study was to evaluate the effect of using a patency file on apical transportation and curve straightening during canal instrumentation with the ProTaper rotary system. Seventy permanent mandibular first molars with mesiobuccal canals, measuring 18-23 mm in length and with a 25-40° curvature (according to the Schneider method), were selected. The working lengths were determined and the teeth were mounted and divided into two experimental groups: (A) prepared by the ProTaper system without using a patency file (n = 35) and (B) prepared by the ProTaper system using a patency file (n = 35). Radiographs taken before and after the preparation were imported into Photoshop software and the apical transportation, and curve straightening were measured. Data were analyzed using independent t-test. Partial correlation analysis was performed to evaluate the relationship between the initial curvature, transportation, and curve straightening (α = 0.05). Using a patency file during canal preparation significantly decreased both apical transportation and curve straightening (P < 0.001). There were significant relationships between the angle of curvature, transportation and curve straightening in pairs (P < 0.001). Apical patency is recommended during root canal preparation with the ProTaper rotary system.

An in vitro comparison of cyclic fatigue resistance of ProTaper universal and GT series X files

Objective: The aim of this study was to compare the cyclic fatigue resistance of two nickel-titanium (NiTi) endodontic instruments from ProTaper and GT series X files. Study Design: Cyclic fatigue test was realized with instruments from ProTaper: F1 and F3 (Denstply Maillefer, Ballaigues, Switzerland) and GT-X: 20.06 and 30.08 (Dentsply Tulsa Dental, Tulsa, Oklahoma, United States of America). A total of 320 instruments were rotated in 4 curved artificial canals with different angles and radius of curvature. The time and cycles to failure were calculated. The data was compared using a Mann-Whitney, Kruskall-Wallis, and Kolmogorov-Smirnov tests, with a significance level of p<0.05. Results: GT-X files rotated for a significantly longer period of time before separation occurred, thus GT-X files where more resistant to the cyclic fatigue compared with ProTaper. Conclusion: GT-X files have a greater resistance to cyclic fatigue, this fact can be caused by the use of the Ni-Ti alloy “M-Wire”.

Key words:Endodontics, GT-X files, ProTaper files, cyclic fatigue.

Apically extruded debris and irrigant with two Ni-Ti systems and hand files when removing root fillings: a laboratory study

AIM

To compare the amount of apically extruded debris and irrigant produced by two Ni-Ti instruments and hand files when removing root fillings, and to compare two experimental models.

METHODOLOGY

Sixty single straight root canals in human mandibular premolars were prepared with K-files and filled with gutta-percha and AH Plus sealer. The teeth were randomly divided into three groups of 20 for removal of the root filling material with Reciproc files (Group 1, RP), Mtwo retreatment files (Group 2, MR) or hand files (Group 3, H). Each group was then equally divided into experimental subgroups: A, with 1.5% agar gel model (AG); B, with empty tube model (ET). Apically extruded debris and irrigant was quantified by subtracting the initial weight of the test apparatus without a tooth from its weight after the root canal retreatment. Comparative analysis of the amount of apically extruded debris and irrigant for each of the instruments and the experimental models was performed. Time for gutta-percha removal was recorded. Data were statistically analysed using one-way analysis of variance.

RESULTS

Removal of root fillings with two Ni-Ti instruments produced less apically extruded debris and irrigant than hand files in both experimental models (P < 0.05). More apically extruded debris and irrigant was produced with Reciproc files than Mtwo retreatment files using the 1.5% agar gel model (P > 0.05). Significantly more apically extruded debris and irrigant was produced with Reciproc files than Mtwo retreatment files using the empty tube model (P < 0.05). The time required to remove the root fillings followed Reciproc<Mtwo R<hand files (P < 0.05).

CONCLUSIONS

All the instruments produced apically extruded debris and irrigant. The two Ni-Ti instruments produced less apically extruded debris and irrigant than hand files. A 1.5% agar gel can provide resistance to apically extruded debris and irrigant and may represent the clinical situation better than the empty tube model.

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.

Apical extrusion of debris and irrigants using hand and three rotary instrumentation systems − An in vitro study

Introduction:

Sterilization of the root canal is a prime aim of successful endodontics. The cleaning and shaping of the canal is directed as achieving this goal. The extrusion of apical debris has a deleterious effect on the prognosis of root canal treatment. Several instrument designs and instrumentation techniques have been developed to prevent this.

Materials and Methods:

Forty caries free single rooted human mandibular premolar teeth were divided in four groups of ten teeth each. Teeth in each group were instrumented until the working length with rotary ProTaper, K3, Mtwo systems, and hand K-type stainless steel files. Debris and irrigant extruded from the apical foramen were collected into vials and the amounts were quantitatively determined. The data obtained were analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests.

Results:

The results show that all instrumentation techniques produced significant amount of extruded debris and irrigant. The engine-driven nickel-titanium systems showed less apical extrusion of debris and irrigant than manual technique. No statistically significant difference was found between the groups at [P > 0.05]. Maximum apical debris and irrigant extrusion was seen with K-file group and least in the Mtwo group.

Conclusions:

The use of rotary files and techniques to perform instrumentation does show less extrusion of the debris and irrigant from the apex. This can contribute to more successful endodontic therapy.

Influence of apical enlargement in cleaning and extrusion in canals with mild and moderate curvatures

Optical microscopy and morphometric analysis were used in this study to evaluate, in vitro, the cleaning of the apical region in root canals with mild or moderate curvatures subjected to biomechanical preparation with a rotary system, as well as to assess the amount of extruded material to the periapical area. Lateral incisors (n = 32), 16 with curvature angles smaller or equal to 10º (GI) and 16 between 11º and 25º angles (GII) were submitted to Hero 642 rotary instrumentation with different surgical diameters: (A) 30.02 and (B) 45.02. Irrigation was performed at each change of instrument with 5 mL of ultrapure Milli-Q water and the extruded material through the apical foramen was collected. Root cross-sections were subjected to histological analysis by optical microscopy (×40) and the images were evaluated morphometrically using the Image Tool software. Quantification of the extruded material was performed by weighing after liquid evaporation. ANOVA showed no statistically significant differences (p>0.05) among the groups with respect to the procedures used to clean the apical region. Considering the amount of extruded material, the Tukey's HSD showed that canals with mild curvature prepared with the 45.02 surgical diameter showed significantly higher values (p<0.05) that those of the other groups, which were similar between themselves (p>0.05). In conclusion, the effect of cleaning the apical region did not differ in the groups, considering root curvature and the surgical diameter of instruments used for apical preparation. The amount of extruded material was greater in canals with mild curvature that were prepared with the 45.02 surgical instrument diameter.

Comparison of debris extruded apically and working time used by ProTaper Universal rotary and ProTaper retreatment system during gutta-percha removal

Objective

The aim of this study was to evaluate the in vitro action of ProTaper retreatment files and ProTaper Universal in the retreatment of mandibular premolars.

Material and methods

The amount of debris extruded apically was measured and the time to reach the working length and to complete the removal of gutta-percha was observed. Thirty teeth had their canals prepared using ProTaper Universal files and were obturated by the single cone technique. The teeth were then stored at 37ºC in a humid environment for 7 days. During the use of the rotary instruments for root canal filling removal, the apical portions of the teeth were attached to the open end of a resin tube to collect the apically extruded debris.

Results

ProTaper Universal files were significantly faster (p=0.0011) than the ProTaper retreatment files to perform gutta-percha removal, but no significant difference was found between the files regarding the time to reach the working length or the amount of apical extrusion.

Conclusions

ProTaper Universal rotary had better results for endodontic retreatment, and both techniques promote similar apical extrusion of debris.