|Year : 2022 | Volume
| Issue : 2 | Page : 80-85
Quantitative evaluation of apically extruded debris during root canal preparation with reciprocating single file system, continuous rotary multiple file system and manual technique: An in vitro study
Pratima Mohana1, Dax Abraham2, Alka Gurawa2, Alpa Gupta2, Parul Chauhan2, Arundeep Singh2, Sucheta Jala2
1 Former Post Graduate Student, Department of Conservative Dentistry and Endodontics, Manav Rachna Dental College, Faridabad, Haryana, India
2 Department of Conservative Dentistry and Endodontics, Manav Rachna Dental College, Faridabad, Haryana, India
|Date of Submission||05-Sep-2021|
|Date of Decision||07-Dec-2021|
|Date of Acceptance||17-Jan-2022|
|Date of Web Publication||01-Jul-2022|
Dr. Alka Gurawa
Department of Conservative Dentistry and Endodontics, Manav Rachna Dental College, Faridabad, Haryana
Source of Support: None, Conflict of Interest: None
Aim: The aim of the study is to evaluate and compare the quantity of apical debris extrusion from the root canals during biomechanical preparation by various rotary (reciprocating, Protaper Next [PTN] continuous) and manual hand filing system and by means of Crown-Down and Step Back techniques.
Materials and Methods: Eighty mature, human mandibular premolars with single canals were randomly divided into four groups of twenty teeth each. Each group was instrumented using one of the four instrumentation systems: Group A: WaveOne, Group B: PTN, Group C: Hand file with Crown Down, Group D: Hand file with Step Back. Extruded debris was collected in preweighed Eppendorf tubes and the extruded irrigant was evaporated. The weight of the dry extruded debris was established by comparing the pre and post-instrumentation weight of Eppendorf tubes for each group.
Results: Mean comparison of groups in different instrumentation by ANOVA presented that hand file with Step-Back technique is showed maximum amount of apical extrusion debris and continuous rotary file system showed the minimum amount of extrusion debris (P < 0.001).
Conclusions: The current ex vivo study demonstrated reciprocating single file WaveOne and continuous rotary multiple file system lead to significantly less debris extrusion than manual hand file techniques. Reciprocating single file WaveOne extruded more debris than continuous rotary PTN multiple file system. More amount of debris was extruded in the group with Step-Back hand filing than Crown-Down technique.
Keywords: Apical extrusion, Crown-Down technique, debris, Protaper next, rotary Ni-Ti instruments, Step-Back technique, WaveOne reciprocating file system
|How to cite this article:|
Mohana P, Abraham D, Gurawa A, Gupta A, Chauhan P, Singh A, Jala S. Quantitative evaluation of apically extruded debris during root canal preparation with reciprocating single file system, continuous rotary multiple file system and manual technique: An in vitro study. Endodontology 2022;34:80-5
|How to cite this URL:|
Mohana P, Abraham D, Gurawa A, Gupta A, Chauhan P, Singh A, Jala S. Quantitative evaluation of apically extruded debris during root canal preparation with reciprocating single file system, continuous rotary multiple file system and manual technique: An in vitro study. Endodontology [serial online] 2022 [cited 2022 Sep 27];34:80-5. Available from: https://www.endodontologyonweb.org/text.asp?2022/34/2/80/349568
| Introduction|| |
Postoperative and inter-appointment flare-ups are undesirable occurrences that can take place due to mechanical and chemical factors that include the over instrumentation, extrusion of medications, filling materials, or irrigants beyond the apical foramen. Chemomechanical preparation is one of the crucial requirements of root canal therapy which includes the utilization of intracanal irrigants to facilitate adequate cleaning and disinfection within the root canal system and allows removal of all organic debris and microorganisms. The extrusion of infective material from the root canal system during instrumentation was first time confirmed by Chapman et al. Vande Visse and Brilliant conducted a study to evaluate the difference in the quantity of apically extruded debris in root canals with or without irrigation and came to a conclusion that irrigation was a procedure that expedites periapical extrusion of intracanal debris whereas no collectible debris was found with instrumentation without irrigants., This extrusion of debris can hasten an inflammation in the periapical area and results in hampered healing, postoperative complications, such as flare-ups or short-/long-term failure. However, irrigation is a determining factor of chemomechanical preparation, and eliminating it from the protocol may cause the failure of root canal treatment. So instead of removing irrigation from root canal treatment, a modification in instrumentation technique is a more legitimate option to reduce apical extrusion debris.
The kinematics, the number of files employed, cutting efficiency, and the cross-section of the files have all been shown to affect apical extrusion of the debris, suggesting the need for further investigating these commonly used techniques.,, With continuous evolution and advancement in the endodontic field, acceptance of rotary instrumentation has increased but hand files remain central to endodontic practice. The Hand files allow the clinician to manually “feel” the unseen dimension of the canal anatomy beyond the illustration of radiographs. Overall, K-files are the universal hand files that are commonly used. There is a continuous expansion from hand files to various modern-day rotary systems. Grouping of these files from 1st to 5th generation by Dr. Clifford J Ruddle based on passive and active cutting made it easier for the clinician to judiciously use various rotary systems.,
Protaper Next (PTN), the 5th generation files have been designed such that the center of mass and/or the center of rotation are offset. Whereas the new WaveOne NiTi file system from Dentsply Maillefer is a single-use, single-file system to shape the root canal completely from start to finish.
However, the phenomenon of apical extrusion is an undesirable side effect of shaping procedure that leads to inflammation, postoperative pain, and delayed peri-radicular healing as discussed above. Attempts are made to reduce the extrusion with the invent of various instrument systems. Hence, it is worth quantifying debris extruded with various instrumentation techniques. Therefore, the present study intends to focus on the quantitative evaluation of apically extruded debris during chemomechanical preparation with the rotary sequence of continuous and reciprocating systems against the Hand K-file with the Crown-Down and Step-Back techniques. The null hypothesis of the study is that there will be no significant difference in the weights of debris extrusion among rotary and manual instrumentation groups used in the study.
| Materials and Methods|| |
Eighty freshly extracted human mandibular premolars meeting the inclusion criteria were collected. This study was conducted in the Department of Conservative Dentistry and Endodontics, Manav Rachna Dental College in collaboration with the Department of Microbiology, Manav Rachna Dental College. Ethical approval was taken from the Institution's Ethics Committee.
- Teeth with mature apex
- Teeth with single root and single canal
- Teeth with single apical foramen.
- Carious or endodontically treated teeth
- Teeth with canal calcifications and open apices
- Teeth with internal/external resorption
- Teeth with dilacerated root.
Eighty freshly extracted human mandibular premolars, meeting the inclusion criteria, were collected. Soft-tissue remnants and calculus on the external root surface were removed with an ultrasonic scaler tip. The presence of single straight root canals and mature root formation was confirmed by radiographs in the buccolingual and mesiodistal direction of all teeth. Teeth were examined under a dental operating microscope to verify the presence of a single apical foramen. Thereafter teeth were stored in normal saline until use.,, Access cavities were prepared with high-speed #2 round diamond bur with constant water spray., Apical patency of all root canals was confirmed with the #10 K file. The buccal cusp of each tooth was grounded flat to standardize tooth length at 20.00 mm., Working length (WL) was determined using a #15 K file which was introduced into the root canal until it is observed at the apical foramen. Endodontic WL was then determined by deducting 1 mm from the initial length.
The teeth/samples were randomly divided into 4 groups based on the file system used for biomechanical preparation/cleaning and shaping
Empty Eppendorf tube weight was measured. The measurement for each tube was calculated after averaging three consecutive weights. A hole in the stopper of each tube was created by placing a hot instrument and the tooth to be instrumented was forced into the stopper up to the level of cementoenamel junction and was secured to prevent the leakage of coronal extruded debris and irrigant. An Eppendorf tube along with the tooth was placed in a glass vial. The operator view was shielded from seeing the root apex during the instrumentation procedure by a dental dam. A needle was placed alongside the stoppers to balance the internal and external air pressures.
Myers and Montgomery's method of debris collection was used to evaluate the debris extruded during the cleaning and shaping of root canals. This collection method contains a glass vial with a stopper. The stopper has a hole through which the tooth to be instrumented is secured and to equalize internal and external pressure, a 25 gauge needle is placed into the stopper. This glass vial collects the extruded debris which is again placed in a glass flask. Two important things that are to be remembered are, first the assembly should be secured to prevent any movement. Second, a shield with a rubber dam should be formed around the flask so that the operator performing the procedure is not able to see the root, he or she is working on. The methodology also includes weighing the collecting tubes before and after instrumentation with precise microbalance and calculating the net weight difference.
Group A: WaveOne
A large WaveOne file (WO, 40/.08, Dentsply Maillefer) was used in a WaveOne electric motor (Dentsply Maillefer) in reciprocating, slow in-and-out pecking motion according to manufacturer's instructions. After the use of 3–4 pecks up and down movement, the file was withdrawn from the canal; flutes of the file are cleaned with moist gauze and inspected before re-insertion. After every 3 pecks, the canal is irrigated with distilled water and an aspirator is used to suction overflowed irrigating solution from the tooth crown. Once the instrument negotiated the full WL and reciprocated freely the file, and the tooth from the stoppers of the Eppendorf tube was removed.
Group B: ProTaper next
In this group, the PTN file system was used using an endomotor to prepare canals according to the manufacturer's guidelines for sequence. After every use of the instrument, the canal was rinsed with distilled water along with aspiration for suction of flowing irrigating solution where #10 K file was used to confirm canal patency. This procedure was continued until the X1 file reached the WL. The same procedure was performed with X2, X3, and X4 files.
Group C: Hand file Crown-Down technique
Coronal enlargement was performed with #2, #3, #4 gates glidden (GG) drills. Canal preparation was commenced with the #55 K file till the middle third of the canal. As resistance for #55 was felt, the next smaller sized instrument #50, followed by #45 and #40 were inserted to the measured endodontic WL. After every use of the instrument, the canal was rinsed with distilled water along with aspiration for suction of flowing irrigating solution where #10 K file was used to confirm canal patency. Thus, the apical preparation was completed with the #40 K file.
Group D: Hand file Step-Back technique
Step-Back preparation was carried out according to Mullaney as Phase I, Phase II (Phase IIA, Phase IIB). The instrument was advanced in watch winding motion and continued until the file was loose in the position followed by the next larger #15 K file in the same manner. Each file was used in push-pull motion with apical enlargement up to #40/0.02. After instrumentation with each file, the canal was rinsed with distilled water along with aspiration for suction of flowing irrigating solution where #10 K file was used to confirm canal patency. Then, for Step-Back preparation; the #45 K file was set 1 mm short of WL. The progressive filing from #45 K file to 55 K file each at a length 1 mm shorter than the previous file. A GG drill starting with smaller size #2 was gradually increased to #3, #4 extended to mid area of the canal, as the beginning of phase II A. Phase II B-returned to #40 H file to smooth all around the walls was used in vertical push-pull strokes.
To standardize the volume of irrigant, total 8 ml (5 ml + 3 ml) of distilled water was used throughout the procedure irrespective to type of file system. Once instrumentation was finished in all groups, the root surface of each tooth was washed into the tube to collect the debris adhering to the root surface with 1 mL of distilled water., The tubes with debris and the irrigant were placed in the incubator for 37°C for 10 days before weighing the dry weight. After the incubation period of 10 days, the dry weight of the tubes was then weighed to calculate the difference in net weights. All the tubes were weighed 3 times and after subtracting the initial weight from the last weight measured, the net weight of the extruded debris was determined. These net weights were then sent for statistical analysis.
After tabulation of all the data, statistical tests were performed using the Statistical software IBM SPSS statistics 18.0 (IBM Corporation, Armonk, NY, USA). Mean values were compared between two groups with the help of a t-test. If the significance value (P value) is <0.05, then we can say that there is a significant difference between the mean value of two groups at 95% confidence level (significant) and if the P < 0.01 in that case, the significance level will be 99% confidence interval (highly significant), otherwise (P > 0.05) mean difference is considered as non-significant.
| Results|| |
The comparison between rotary and hand instrumentation techniques resulted that rotary instrumentation system (0.24 mg) showed significantly lesser amount of debris than hand instrumentation technique (0.76 mg) (P < 0.001) [Table 1]. Among the two rotary instrumentation techniques, the PTN file system (0.11 mg) showed significantly less amount of debris than the WaveOne file system (0.37 mg) with the mean difference of 0.26 ± 0.01 [Table 2]. Whereas, when two hand instrumentation techniques were compared, less amount of extrusion debris was present with the Crown-Down technique (0.62 mg) than Step-Back technique (0.9 mg) with the mean difference of 0.28 ± 0.01 [Table 3].
The result of the mean comparison of groups in different instrumentation by ANOVA presented that hand file with Step-Back technique showed maximum amount of apical extrusion debris and continuous rotary file system showed the minimum amount of extrusion debris [Table 4].
|Table 4: Mean comparison of groups in different instrumentation by ANOVA|
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| Discussion|| |
The root canal instrumentation is intended to provide a biological environment that is contributive, both to healing as well as to establish a canal shape that is acceptable to sealing. However, all instrumentation techniques have been proven to support apical extrusion of debris to varying degrees (Al-Omari and Dummer 1995). There are two types of factors that could affect the extrusion of debris; natural factors and mechanical factors. Natural factors include anatomy of the apical constriction, quantity, and momentum of flow of the irrigation in the root canal, and position of the tooth in the jaw.,, Whereas, mechanical factors include the final apical size of the instrument, instrumentation technique, design of instrumentation. Some other factors also affect the amount of debris like needle type, insertion depth of the needle, root curvature, preparation endpoint, and microhardness of dentin. Research has concluded that open-tip needles extrude significantly more debris than closed-tip needles.,, The extrusion of the irrigator decreases when taken away from the WL. It was further added that root canal curvature did not have a significant effect on apical extrusion., Myers and Montgomery clearly showed that preparation endpoint at a WL, 1 mm short of canal length, contributed to significantly lesser debris extrusion.
Myers and Montgomery methodology system has received the most attention and was adopted by many studies to quantitatively evaluate the apical debris extrusion.
PTN system files are designed such that the center of mass and/or the center of rotation are offset which generates a traveling mechanical wave of motion along the active portion of a file. This swaggering effect serves to minimize the engagement between the file and dentin. It also can afford more cross-sectional space for enhanced cutting, loading and auguring debris out of a canal compared to a file with a centered mass and axis of rotation. Importantly, an offset file design decreases the probability of laterally compacting debris and blocking root canal system anatomy. The reciprocating working motion consists of a counter-clockwise (cutting direction) and clockwise (release of the instrument), where the angle of cutting direction is greater than the angle of reverse direction.
On comparing the mean debris extruded by WaveOne and PTN, PTN resulted in significantly lesser debris extrusion (mean = 0.11) than WaveOne (mean = 0.37) (P < 0.001). These results are in concurrence with the studies conducted by Koçak et al. (2013), Topçuoğlu et al. (2016), and Pawar et al. (2015). They concluded that teeth prepared with reciprocal groups had significantly greater amounts of extruded debris than the PTN group.,, whereas Ozsu et al. in 2014 concluded that SAF produced the least debris, whereas the difference PTN and WO were not statistically significant. Koçak et al. (2015) attributed that off-set rectangular cross-section, the nonuniform and reduced contact points between PTN file and root canal wall enhances auguring of debris out in coronal direction rather than extruding it apically and reduces the amount of extrusion debris.
Comparisons of debris extruded by two hand instrumentation techniques showed that both the techniques produced a collectible amount of debris. Step-Back technique (mean = 0.90) resulted in significantly higher debris extrusion than Crown-Down method (P < 0.01). The present study concluded that Step-Back technique extruded a higher amount of debris than the Crown-Down technique. This may be explained as the push-pull or filing action or linear action of K-file tends to push more debris apically. This was in accordance with the study by Al-Omari and Dummer in 1995. The results of this study concluded that the maximum amount of debris was noticed in the group with the Step-Back technique and the least amount of debris seen in groups with balanced force and Crown-Down technique. Ruiz-Hubard et al. 1987 and Reddy and Hicks 1998 also concluded that the amount of debris forced apically during the Step-Back technique was significantly greater than the Crown-Down technique.,
Comparing the mean debris extrusion by rotary instrumentation (WaveOne and PTN) to hand instrumentation (Step Back-Crown-Down technique) resulted in significantly less debris extrusion (P < 0.01). Based on the results of the present study, it was concluded that rotary instruments extrude lesser debris than K Files. This was in concurrence with studies by Ferraz et al. in 2001, Zarrabi et al. in 2001, and Madhusudhana et al. in 2010 who compared rotary instruments with Step-Back technique and found out that the amount of extruded debris was greater with Step-Back technique than rotary instruments.,
This may be explained by the fact that the rotary motion of engine-driven instruments avoids compaction of the debris in root canals and tends to direct debris towards the orifice. On the other hand, K files act like a piston in the apical third which is likely to push the debris through the apical foramen. Also, due to lesser taper of the Hand K files, the space available to flush out the debris is less.
Limitations of the study
In vital cases, more resistance to apical extrusion of debris is seen as the periapical and pulpal tissues may help to control the apical and lateral penetration of an irrigating solution but in the present study, the counterfeit of periapical or pulpal tissues is absent. The presence of positive and negative pressure at the apex as well as normal and pathological periapical tissues also affect the results. These results are restricted to mature apices but cannot be applied to teeth with an open apex. As it was not possible to make standardization in terms of root dentin hardness, this factor may be considered as one of the drawbacks of these types of studies. Histological variations may occur between each individual tooth.
| Conclusions|| |
The present study concluded that all the file systems lead to debris extrusion. The current ex vivo study demonstrated reciprocating single file WaveOne and continuous rotary multiple file system leads to significantly less debris extrusion than manual hand file techniques. Reciprocating single file WaveOne extruded more debris than continuous rotary PTN multiple file system. More amount of debris was extruded in the group with Step-Back hand filing than Crown-Down technique. Further studies need to be done to focus on instrumentation technique that reduces apically extruded debris along with the abolishment of bacteria that especially cause endodontic flare-ups.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]