| Abstract|| |
Introduction: The role of microorganism and their products in the initiation, propagation, and persistence of periradicular periodontitis has been established. One of the major goals of the treatment of infected root canals of teeth with apical periodontitis is to promote maximal reduction in the intracanal bacterial populations. Engine-driven nickel-titanium instruments possess the latest generation of root canal instruments. The possible benefit of rotary instrumentation over other instrumentation techniques regarding cleaning and disinfecting effects would be irrigant warming and/or turbulence caused by the mechanical rotation of instruments. Furthermore, reciprocating instrument has been introduced for root canal preparation. It has been shown that instruments subjected to reciprocation have increased resistance to fatigue and longer usual life when combined with instruments used in continuous rotation motion. The reciprocating system uses single-file instrumentation technique which can shape and clean the canal in a shorter period and together with the lesser amount of antimicrobial agent.
Objective: The objective of this study is to compare and evaluate the microbial reduction of rotary and reciprocating systems on microbial reduction.
Search Strategy: A search was performed in Electronic databases (i.e., PubMed, Cochrane library, Science direct, Lilac, Sigle) using following search terms alone and in combination by means of PubMed search builder from January 1985 to December 2017.
Selection Criteria: Studies were selected if they met the following criteria: In vivo studies comparing rotary and reciprocating system in asymptomatic apical periodontitis patients.
Main Results: The results showed that the reciprocating system exerted an almost similar antibacterial effect when compared with the rotary system.
Conclusion: The present systematic review does not provide concrete evidence to show increased antibacterial efficacy of reciprocating system as compared to the rotary system. Furthermore, clinical trials are required to evaluate the efficacy of various instrumentation systems in reducing bacteria from the root canal system.
Keywords: Apical periodontitis; microbial reduction; reciprocating files; rotary files
|How to cite this article:|
Siddique R, Nivedhitha MS. Effectiveness of rotary and reciprocating systems on microbial reduction: A systematic review. J Conserv Dent 2019;22:114-22
|How to cite this URL:|
Siddique R, Nivedhitha MS. Effectiveness of rotary and reciprocating systems on microbial reduction: A systematic review. J Conserv Dent [serial online] 2019 [cited 2019 Jul 17];22:114-22. Available from: http://www.jcd.org.in/text.asp?2019/22/2/114/257587
| Introduction|| |
Apical periodontitis is a disease caused by bacterial infection of the root canal system which can be controlled by proper endodontic treatment., Removing pulp tissue remnants, microorganism, and microbial toxin from root canal system is necessary for the success of root canal treatment. The main goal of root canal treatment is to reduce the amount of bacteria and their by-products which contributes to the perpetuation of apical periodontitis.,, Lipopolysaccharides are most important by-products present on the outer layer of Gram-negative bacterial species.,, Root canals can be cleaned by instrumentation along with irrigants and intracanal medicaments. To make canal preparation easier, several mechanical devices and techniques were introduced to further improve the effectiveness of instrumentation. The devices may be classified as either manual or machine-assisted for root canal instrumentation. Machine-assisted endodontic instruments help in easier and faster instrumentation. A machine-assisted technique includes automated root canal preparation, sonic and ultrasonic preparation, laser systems, and non-instrumental techniques.
Stainless steel instruments been used in previous years have showed more chances of canal transportation. They have become dispensable with the introduction of the more flexible nickel-titanium (NiTi) instruments. With the introduction of M-wire or control memory wire improved the instruments (easier, faster and better root canal shaping, greater resistance to fracture).
According to Hulsmann et al. (2005), Oltramare (1892) was first to give reference to rotary instrumentation, who used fine needles with rectangular cross sections that could be attached to a dental handpiece. The endodontic handpiece was first introduced by Rollins (1899) for root canal instrumentation that was used with specially designed needles at 100 rpm (Milas 1987). The use of stainless-steel instruments was limited after the introduction of NiTi endodontic hand instruments by Walia et al. (1988) thereby avoided canal transportation. Recently, Diemer et al. 2013 have introduced a new type of rotary motion called asymmetrical rotary motion. Asymmetrical rotary motion (waves of motion traveling along the active part of the file) includes off-centered cross-section which is produced by design features of the file, that is not related to endodontic motors. The new systems come into practice as asymmetrical motion were Revo-S (Micro-Mega, Besancon, France), followed by ProTaper Next (DENTSPLY Tulsa Dental Specialties), new generation OneShape (Micro-Mega) and TRUShape 3D Conforming Files (DENTSPLY Tulsa Dental Specialties).
Endodontic instruments were initially manufactured using carbon steel. Their strength and quality vastly increased with the introduction of stainless steel. In the late 1980s, Ni–Ti alloy took a major change in endodontic Instruments. Ni–Ti alloy confers two distinct advantages: superelasticity and high resistance to cyclic fatigue. The crown-down technique is the key factor contributing to the backbone of Ni–Ti rotary instrumentation, which involves three phases as follows: coronal access, coronal-middle preparation, and apical preparation. Before commencement of large rotary files used to enlarge the canal short of the apex before smaller and smaller files are introduced until full working length can be achieved. The apical third has been enlarged to the desired size using larger files. Most other techniques that are used with continuous rotation system are simply variations of the crown-down.
Variety of different endodontic filing systems is available on the dental materials market today. Most of these tapered files which follow ISO standards are compatible with the crown-down instrumentation technique. Some of them include Profile, Vortex, GT, EndoSequence, K3, HERO, Twisted File, and Hy-Flex. The ProTaper Universal system has unique where its taper varies over the course of its long axis. Dr. Cliff Ruddle, Dr. John West, and Dr. Pierre Machtou developed the system in the mid-1990s. It comprises 7 files: 2 shaping files and 5 finishing files. Each Protaper Universal file is capable of working to full length. A wider diameter of the shaping files takes care of coronal-middle preparation phase and the desired apical size determines the number of finishing files in the sequence that are used.
The ProTaper Next has introduced into the market with expectations of better canal shaping and removal of bacteria from root canal walls. It has rectangular cross-section unlike ProTaper universal (convex triangular) cross-section which is off-centered. The axis of rotation of ProTaper universal is different than its center of mass and ProTaper universal limits the amount of surface area in contact between the file and canal wall. Protaper Next includes five files and is designed to attain full apical preparation with fewer Instruments while producing slightly less tapered sizes. The files, X1–X5, have apical Sizes of 0.17 mm, 0.25 mm, 0.30 mm, 0.40 mm, and 0.50 mm and tapers of 0.04 mm, 0.06 mm, 0.07 mm, 0.06 mm, and 0.06 mm, respectively. In comparison to ProTaper Universal, ProTaper Next files have been found to possess significantly enhanced performance with respect to cyclic fatigue resistance and in minimizing extruded debris, microcrack induction, and canal transportation.
Various endodontic reciprocating handpieces have been developed (Prichard 2012) after reciprocation was first introduced in 1964 with the Giromatic system (Micro-Mega). The Giromatic system, Endo-Gripper (Moyco Union Broach, Montgomeryville, PA, USA), Intra-Endo 3 LD (KaVo, Biberach, Germany) and Dynatrak (DENTSPLY DeTrey, Konstanz, Germany) which seems to operate with equal angles of 90° clockwise (CW) and counter CW (CCW) motion. Since Giromatic system produced greater procedural errors than hand filing, it lost popularity gradually.
The M4 (SybronEndo, Orange, CA, USA), Endo-Eze (Ultradent Products Inc., South Jordan, UT, USA) and Endo-Express SafeSider (Essential Dental Systems, South Hackensack, NJ, USA) systems are recent files which use reciprocating handpieces that utilize 30° angles of CW and CCW rotation. These handpieces enable the formation of an endodontic glide path using small stainless steel hand files.
The new era of NiTi alloys regained popularity of reciprocating systems and endodontic torque control motors. Roane et al. described a balanced force technique for curved canals and included unequal CW and CCW motions with hand file. The concept of single-file reciprocation was introduced by Yared which was based on a balanced-force technique and used the ProTaper F2 instrument (DENTSPLY Tulsa Dental Specialties) (a flute-designed instrument with cross-sectional geometry that aids in the cutting of the dentine in the CW direction) with unequal CW and CCW rotational motion (144° CW and 72° CCW). This development points to the fact that the instruments required five rotations to complete a full 360° rotation. At the same time, due to this motion, the elastic limit of the instrument was not exceeded.
The manufacturers introduced single-file reciprocating systems including WaveOne (DENTSPLY Tulsa Dental Specialties) and Reciproc (VDW, Munich, Germany) based on developments in motions. In case if instruments have CCW cutting direction, it would cut when the CCW movement was greater than the CW movement. However, all of the instruments are designed for cutting in the CW direction except for reciprocating instruments. There are more chances of instrument will neither cut nor penetrate into the canal if one tries to use CW cutting instruments with the reciprocating motors where CCW motion is greater than CW motion.
In the majority of cases, a single file is sufficient to complete root canal preparation in single-or multiple root canal systems. The files work in a reverse “balanced force” cutting motion which is driven by a preprogrammed motor (X-Smart Plus motor fitted with 6:1 reducing hand piece) (DENTSPLY/Maillefer) that is capable of turning the files in a back and forth “reciprocating” motion instead of a rotary motion, The CCW movement of 150 degrees is capable of advancing the instrument apically as the dentine on the root canal wall is engaged and cut. This is followed by 30° CW movement thereby ensures that the instrument disengages before excessive torsional stress is transferred onto the metal alloy and before the instrument can bind (taper lock) into the root canal. CCW rotation allows the instrument to advance apically into the root canal.
Reciprocating endodontic motors can be open or closed motors, where open motors ([ATR Vision; ATR, Pistoia, Italy], [iEndo Dual; Acteon, Merignac, France], [SAF pro System; ReDent-Nova, Ra'nana, Israel]) allows modification of angles and speed, whereas closed motors ([WaveOne], [Reciproc], [Elements motor; SybronEndo], [ATR Technika; ATR]) were not allowed such modifications.
Reciprocating systems provides greater comfort for both patient and professional as it reduces working time, making it four times faster than the traditional rotary file system. Its a matter of debate regarding the ability of single-file system to shape and clean the canal in shorter period and together with the lesser amount of antimicrobial agent when compared with multiple file rotary system. According to Alves FR et al. 2012, single-file reciprocating instrumentation technique showed similar intracanal bacterial reduction when compared with rotary instrumentation if the irrigant volume and the time of irrigation are similar.
The aim of this systematic review was to assess the microbial reduction of rotary and reciprocating systems in asymptomatic apical periodontitis patients.
Does the reciprocating system bring about significant removal of microbes from root canal space compared to rotary systems?
There is no significant difference between the anti-bacterial effectiveness of rotary and reciprocating system in microbial reduction.
There is a significant difference between the anti-bacterial effectiveness of the rotary and reciprocating system in microbial reduction.
The PICO question can be framed as follows:
- Population - patients with asymptomatic apical periodontitis
- Intervention – reciprocating system
- Comparison – rotary system
- Outcome – microbial reduction.
| Materials and Methods|| |
The present systematic review was carried out following approval of Institutional Review Board (SRB/MDS/ENDO/17-18/0025).
Detailed search strategies were developed for the database searched for identification of studies included or considered for this review.
- Cochrane Library (CENTRAL)
- Science Direct
There were no language restrictions.
The following journals were hand searched:
- International Endodontic Journal
- Journal of Endodontics.
Criteria for considering studies for this review:
Types of participants:
Teeth with asymptomatic apical periodontitis
Types of interventions:
Comparison– Rotary systems.
Types of outcome measures:
Types of studies:
In vivo studies.
The following studies were excluded,
- In vitro studies
- Animal studies
- Ex vivo studies
| Results|| |
The search identified 520 publications, out of which 17 duplicate articles and 481 articles were excluded after the title search. Full articles were obtained for 8 studies and evaluated. After reading the abstract and full-text article, 5 of these were excluded. Therefore, a total of three publications fulfilled all criteria for inclusion. [Table 1] shows the search methodology. Some of the characteristics of excluded articles are given in [Table 2]. [Figure 1] shows the PRISMA flow diagram and general information of the selected articles are given in [Table 3].
|Table 3: General information of variables of interest and interpretation|
Click here to view
| Discussion|| |
The results of this systematic review confirm that more evidence-based research in this area is needed and that there have been limited randomized controlled clinical trials in this area. With the limited information currently available, the best current available clinical evidence suggests that both rotary and reciprocating files exerted almost similar antibacterial effectiveness.
It has been proved that bacteriological conditions of root canal before obturation may influence the long-term prognosis of teeth, with significantly better results with negative cultures. Clinical studies should be carried out to correlate culture-independent molecular data with treatment outcome. It is clearly well-known fact that maximum bacterial elimination is required for long-term prognosis. Studies comparing the long-term outcome after treatment with these instruments should be prompted as they have a long life in the market.
Bacterial reduction in root canals was found significant when compared Reciproc R40 and BioRaCe under the same irrigation protocol. In another study, significant count reductions of Enterococcus faecalis WaveOne and Reciproc were used. Investigators compared three different systems namely Reciproc R25, SAF, and TF systems to check for bacterial reduction in mesial roots of mandibular molars. Results showed that the ability of all systems to promote significant bacterial reduction despite the detection of positive cultures which may be due to the complexity of mesial root canal systems. A clinical study showed that both reciprocating files and rotary full sequence system showed similar effectiveness in reducing endotoxins and cultivable bacteria, but they were not able to completely disinfect all root canal systems analyzed. These results show that the mechanical action of endodontic files on dentin together with adequate exposure to NaOCl irrigation is more effective for disinfection than the number of files used.
Many studies have proved that single-file reciprocating systems and full-sequence rotary systems have similar effect on microbial reduction (Siqueira et al. 2013, Marinho et al. 2015, Martinho et al. 2014, Neves et al.2016).,,,, Marinho et al. (2015) showed that Reciproc, Mtwo, ProTaper, and Race (FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments produced highly significant reductions of the bacterial load, but no significant differences in endotoxin levels were found. However, there are limited data concerning the effect of pure reciprocating motion on bacterial reduction.
Reciproc and BioRaCe have showed significant bacterial reductions despite some number of bacteria were still detected by qPCR in 55% and 50% of the canals. This is in agreement with few studies that used different instrumentation techniques and NaOCl irrigation.,, This bacterial count may still be sufficient to maintain the disease. Bacteria may remain in root canal system due to canal morphology such as isthmi, lateral canals, and apical ramifications which may not be reached by instruments and irrigants., This can be avoided by enlarging canal enough to incorporate bacterial walls in the final preparation. Most of the instrument systems are available in predetermined size series which creates a problem in removing canal bacteria, whereas self-adjusting file system follow root canal morphology, thereby helps in bacterial elimination.
Single-file techniques have been used from start to finish because of its convenience rather than clinically proven effectiveness.,,, Systems with greater number of instruments along with the higher frequency of irrigation during biomechanical preparation reduce microorganisms and endotoxins more likely than single-file system. According to Kakehashi et al., the presence of bacteria is the main cause of the development of periodontal infection and apical periodontitis. The aim of chemo-mechanical root canal preparation is to eradicate residual vital and non-vital pulp tissue and reduce the number of pathogenic organisms. Mechanical instrumentation can disrupt the bacterial biofilm and has the potential to reduce the presence of bacteria in the main root canal. The rotary systems, ProTaper Universal and Mtwo have been shown to provide adequate geometry and substantial bacterial reduction in the root canal.
A recent invitro study compared the influence of the reciprocating single-file technique with conventional rotary instrumentation on the microbial reduction in infected root canals. In their study, they have used WaveOne, Reciproc, ProTaper Universal, Mtwo, and manual instrumentation. The results demonstrated that the bacterial count was significantly reduced after instrumentation in all groups. However, there were no significant differences in the bacterial count reductions effected by the reciprocating, rotary, and manual techniques. The study concluded that reciprocating systems resulted in similar bacterial reductions to those obtained with rotary systems or with the manual instrumentation technique. Similar observations were made by Nabeshima et al. in 2014.
The purpose of this review is to evaluate the antibacterial efficacy of the rotary and reciprocating system in microbial reduction. Three clinical studies fulfilled the criteria for being included in this review (Monica A. S. Neves et al. 2016, DaianaCavalli et al. 2017, Frederico C. Martinho et al., 2014).
A total number of 137 participants were included in this review. Out of 137 participants, 73 subjects received reciprocating instrumentation and 64 participants received rotary instrumentation. Age group of the participants was 16–85 years.
These three randomized controlled clinical trials, all canals were completely instrumented in a single visit. Bacterial load in root canal samples of teeth were checked before (S1) and after (S2) chemo mechanical instrumentation using reciprocating single instrument or a continuously rotating multi-instrument series.
Mostly systematic reviews will perform meta-analysis, which involves the statistical pooling of data from individual studies when the studies are similar. A meta-analysis can yield a more precise overall estimate of the treatment effect. However, meta-analysis may not be appropriate in many situations. Due to the heterogeneity among the studies such as difference in the composite types, sample sizes and follow-up periods, we could not perform a meta-analysis to summarize the data of included studies. Hence, only descriptive evaluation of data has been provided.
Report on quality of evidence looked upon
All 3 studies included in this review have a level of evidence 3(OCEBM, 2011). Thus, the level of evidence is moderate. Risk of bias of 3 studies (Monica A. S. Neves et al. 2016, DaianaCavalli et al. 2017, Frederico C. Martinho et al. 2014) had a high risk of bias. The risk of bias summary and graph [Figure 2] and [Figure 3] were generated using Review Manager 5 software (RevMan 5).
From this systematic review, it can be concluded that microorganism is more likely to be reduced when systems with a greater number of instruments are used.
Implications for practice
Single-file reciprocating systems was found almost similar microbial reduction when compared with rotary systems.
Implications for research
Since the number of randomized controlled clinical trials included in this review is limited, more clinical trials are required to prove the efficacy of various instrumentation systems.
Report of outlier data
No outlier data obtained.
| Summary|| |
The aim of this systematic review was to evaluate the effectiveness of rotary and reciprocating systems in removing bacteria from root canal space. An electronic search was carried out on PUBMED database for the articles which could be used for evaluating the effectiveness of reciprocating system in removing bacteria from root canal when compared with rotary systems.
Article search were selected based up on the pre-stated inclusion and exclusion criteria. A total of three articles were included in this systematic review for detailed evaluation.
The microbial reduction of rotary and reciprocating systems was the primary variable of interest.
Based on the result of this systematic review, we can conclude that single-file reciprocating system exerted almost similar microbial reduction when compared with rotary systems.
| Conclusion|| |
The present systematic review does not provide concrete evidence to show increased antibacterial efficacy of reciprocating system as compared to rotary system. Three articles included in this review have shown a high risk of bias. Further, it also recommends more clinical studies to be done comparing different rotary and reciprocating systems on microbial reduction.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Dr. Malli Sureshbabu Nivedhitha
Department of Conservative Dentistry and Endodontics, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, 162, Poonamallee High Road, Chennai - 600 077, Tamil Nadu
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]