Journal of Indian Society of Pedodontics and Preventive Dentistry
Journal of Indian Society of Pedodontics and Preventive Dentistry
                                                   Official journal of the Indian Society of Pedodontics and Preventive Dentistry                           
Year : 2014  |  Volume : 32  |  Issue : 4  |  Page : 311--316

Comparison of instrumentation time and cleaning efficacy of manual instrumentation, rotary systems and reciprocating systems in primary teeth: An in vitro study


Farhin Katge, Devendra Patil, Manohar Poojari, Jitesh Pimpale, Abhinav Shitoot, Bhavesh Rusawat 
 Department of Pedodontics and Preventive Dentistry, Terna Dental College, Navi Mumbai, Maharashtra, India

Correspondence Address:
Farhin Katge
Department of Pedodontics and Preventive Dentistry, Terna Dental College, Sector 22, Plot No. 12, Nerul (W), Navi Mumbai - 400 706, Maharashtra
India

Abstract

Background: Paediatric Endodontics is an important clinical procedure commonly used to manage pulpally involved or non-vital teeth in children. One of the important steps in root canal preparation in deciduous teeth is the removal of organic debris. Aim: The aim of this study was to compare instrumentation time and cleaning efficacy of manual instrumentation, rotary systems and reciprocating systems in the preparation of primary molar root canals. Materials and Methods: India ink was injected into 120 root canals of maxillary and mandibular primary molars. The teeth were randomly divided into three experimental groups, Group one K-file (n = 30), group two ProTaper (n = 30), group three WaveOne (n = 30) and one control group (n = 30). The root canals were prepared using one of the three file system followed by clearing the teeth with different demineralizing solutions. The results were statistically evaluated using Kruskal-Wallis tests. Results: The file systems were compared at coronal, middle and apical level. In the coronal third, WaveOne showed more ink removal and the difference found was highly significant (P < 0.0001). In the middle third of the root canal, WaveOne performed better than ProTaper and K-file (P < 0.005). At the apical level, there was no statistical difference between the three systems. Conclusion: The reciprocating and the rotary systems showed better cleaning efficacy when compared to manual instrumentation especially, in coronal and middle one third.



How to cite this article:
Katge F, Patil D, Poojari M, Pimpale J, Shitoot A, Rusawat B. Comparison of instrumentation time and cleaning efficacy of manual instrumentation, rotary systems and reciprocating systems in primary teeth: An in vitro study .J Indian Soc Pedod Prev Dent 2014;32:311-316


How to cite this URL:
Katge F, Patil D, Poojari M, Pimpale J, Shitoot A, Rusawat B. Comparison of instrumentation time and cleaning efficacy of manual instrumentation, rotary systems and reciprocating systems in primary teeth: An in vitro study . J Indian Soc Pedod Prev Dent [serial online] 2014 [cited 2019 Aug 19 ];32:311-316
Available from: http://www.jisppd.com/text.asp?2014/32/4/311/140957


Full Text

 Introduction



The main purpose of instrumentation in pulpectomy procedures of primary teeth is the removal of organic debris. [1],[2] Success of the root canal treatment depends on the method and the quality of instrumentation, irrigation, disinfection and three-dimensional (3D) obturation of the root canal. [3]

Conventional endodontic treatment technique for primary teeth remains hand instrumentation. This is time-consuming and often causes fatigue to the operator and child. [4],[5] The introduction of nickel titanium (NiTi) rotary instrumentation has made Endodontics in permanent teeth easier and faster than manual instrumentation, resulting in consistent and predictable root canal shaping. [6] Similar principles of canal debridement and dentin shaping using NiTi can be applied to primary teeth. Rotary instruments were introduced to Pediatric Endodontics by Barr et al., [7] in 2000.

Use of the rotary instrumentation technique transforms the root canal to a more conical shape and thus enhances the quality of obturation. [8] The design and flexibility of NiTi alloy instruments allow the files to preserve the original anatomy of curved canals especially in primary teeth and reduce procedural errors. Disadvantages of NiTi rotary files are the high cost of NiTi rotary systems and the need for training to learn the technique. [7],[9]

The new WaveOne NiTi single-file system has been introduced by Dentsply Maillefer (Ballaigues, Switzerland) in 2011. The system is designed to be used with a dedicated reciprocating motion motor. It consists of three single-use files: Small (ISO 21 tip and 0.06 taper) for fine canals, primary (ISO 25 tip and 0.08 taper) for the majority of the canals, and large (ISO 40 and 0.08 tapers) for large canals. The files are manufactured with MWire (Dentsply Tulsa Dental Specialties) NiTi alloy. [10] The aim of this study was to compare instrumentation time and cleaning efficacy of manual instrumentation, rotary systems and reciprocating systems in the preparation of primary molar root canals.

 Materials and Methods



Approval for this study was taken from the Institutional Review Board of the institution. Eighty-four extracted primary teeth were collected. The sample teeth were virgin without any prior treatment done on them. The exact reasons for tooth extraction were unknown to the researchers, but it was assumed that they were extracted because of caries, periodontal problems, and preventive orthodontic treatment. The inclusion criteria were: Extracted teeth with no external or internal pathological root resorption, absence of perforation in the internal or external furcation area, moderate root angulation and two-thirds of intact root. The exclusion criteria were the presence of pathological root resorption, presence of perforation in the furcation area, severe root angulation and root length less than two third. 120 root canals from 84 teeth were selected for the study.

All teeth were stored in distilled water at room temperature. They were then immersed in 3% sodium hypochlorite (Amdent, India) for one week for disinfection, and then stored in distilled water until they were used for the study. Digital radiographs were taken in a lab for selection of the root canals prior to the instrumentation of root canal. [11] Standard coronal access was achieved with BR 31 diamond round bur (Mani, Japan) and Endo Z (Denstsply Maillefer, Ballaigues, Switzerland) at high speed, under cooling with distilled water. All specimens were then rinsed with saline. The root canals were filled with India ink using a 30 gauge needle syringe. The teeth were left in wet conditions at room temperature for 48 hours. [1]

Thirty root canals were randomly divided in three experimental groups and one control group. All root canals were prepared by the same operator. Group one specimens were instrumented with stainless steel K-files (Denstply Maillefer, Ballaigues, Switzerland). In group two, ProTaper files (Denstply Maillefer, Ballaigues, Switzerland) and in group three, WaveOne system (Denstply Maillefer, Ballaigues, Switzerland) were used for instrumentation. [1] In group four, (30 canals) which was the control group, no instrumentation was done. The actual root canal length was determined visually by inserting an ISO size 10 hand K-file (Dentsply Maillefer, Ballaigues, Switzerland) into the canal until the file tip could be seen at the apical foramen. The working length was calculated by subtracting one millimetre from actual root canal length. [12]

In group one, all 30 root canals were instrumented manually with K-files (Denstply Maillefer, Ballaigues, Switzerland) with the step-back technique up to file ISO size 30. [1] In group two, all 30 root canals were cleaned with the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) in a crown-down technique with two instruments in the following sequence: SX was inserted into the canal to about three millimetre beyond the root canal orifice and S2 file was inserted till the working length. [5] In group three, all 30 root canals were prepared using WaveOne Small file (6% taper) using the crown-down technique. The instrumentation time in each root canal was measured by a chronometer. [13]

In all three experimental groups the canals were flushed with 5 ml normal saline and dried with absorbent paper points. The pulp chamber was then filled with temporary cement (Coltosol, Coltene/Whaledent AG, Switzerland) and apical ends were sealed with sticky wax. The instrumented teeth were then stored in wet conditions.

For evaluation of cleaning efficacy, the teeth were placed separately in 7% hydrochloric acid and the acid solutions were changed daily until the tooth was completely decalcified. The teeth were then washed under running water and dehydrated in a series of ethyl alcohol concentrations: 70% alcohol for 16 hours (changed after eight hours) followed by 80% alcohol for eight hours, 95% alcohol for eight hours, and 100% alcohol for 8 hours. After dehydration, the teeth were cleared in methyl salicylate for 6 hours. [1],[14]

The cleared teeth were examined under a stereomicroscope (SMZ-143 series, Motic Company) at 10X magnification. [11],[13],[15] The scoring was done by an independent blinded examiner. They were scored according to the amount of India ink remaining in the coronal, middle, and apical thirds of the canal on a scale of 0-3 [3],[5],[14] [Figure 1].{Figure 1}

0 -

Total clearing in which the whole canal was completely clean.

1 - Almost complete ink removal.

2 - Partial ink removal.

3 - No ink removal.

The scores thus obtained were tabulated and statistically analyzed by Kruskal-Wallis test using MedCalc Statistical Software version 12.7.2 (MedCalc Software bvba, Ostend, Belgium). The significance of values of time taken for instrumentation with manual, reciprocation and rotary techniques was done with Student's t-test.

 Results



Comparison between the control group and the three experimental groups revealed that files in the three experimental groups were able to remove the ink. The cleaning efficacy of both ProTaper and WaveOne was better than the K-file at the coronal third of the root canal. Amongst experimental groups, at the coronal level WaveOne showed more ink removal and the difference found was highly significant (P < 0.0001).

In the middle third of the root canal, WaveOne performed better than ProTaper and K-file. The difference in their cleaning ability was found to be statistically significant (P < 0.005). In the apical third of the root canal, K-file performed better than other file systems, but the difference was not found to be statistically significant (P = 0.059). When the composite score of all three levels were evaluated, WaveOne was better than the ProTaper and K-file [Table 1] and [Table 2].{Table 1}{Table 2}

The mean value of time spent for instrumentation of canal by the K-file was 6.22 minutes, ProTaper was 3.78 minutes and WaveOne was 2.37 minutes. WaveOne was found to take significantly (P < 0.0001) less time than ProTaper and K-file [Table 3].{Table 3}

 Discussion



Rotary biomechanical preparation of deciduous teeth was first described by Barr et al. [7] There are no clear guidelines for the instrumentation of primary teeth root canals with rotary files. Kuo et al.,[5] found that with the modified protocol, ProTaper Ni-Ti rotary files can be safely and efficiently used for root canal preparation in primary molars. They used a combination of one manual file and two ProTaper instruments (SX and S2). Hence the same technique was followed in our study.

SX file was selected for early coronal enlargement and straight-line access. The cervical constriction in primary molars should be removed to improve the straight-line access which reduces the risk of instrument separation. SX has the greatest range of taper which can be used for the removal of cervical constriction. [16] An S2 file has 0.04 taper and its tip is similar to size 20 K-file, hence it is suitable for use in primary molars. [5]

There are few studies that compare the cleaning ability of manual and rotary instrumentation in primary teeth. The current study compared the cleaning efficacy of manual instrument [K-files], rotary system [ProTaper] and reciprocating system [WaveOne] in the preparation of primary molar root canals.

Our study demonstrated a significant difference in the cleaning ability of rotary and reciprocating systems in coronal third (P < 0.0001) and middle third (P = 0.042) of the primary molar root canal compared to manual instrumentation. Huang QL et al.,[17] Kadhom TH and Al-Hashimi WN [18] showed the similar degree of cleaning efficacy in coronal third and middle third of the root canal. Foschi et al.,[19] also reported that M two and Protaper rotary systems produced a clean canal in the coronal and middle thirds, but were unable to provide the similar cleaning efficacy at apical third level. Our study demonstrates no significant difference in cleaning efficacy between three file systems in the apical third (P = 0.059).

Berutti E et al.,[20] compared WaveOne with ProTaper and demonstrated that WaveOne was better than ProTaper in cleaning efficacy and maintaining the canal anatomy in permanent teeth. Da Forta MF et al.,[21] studied the ProTaper system and concluded that it was efficient at an apical third of the root canal system. Yuo YS and Cho YB [22] compared Reciproc, WaveOne, ProTaper, Profile and K-file and concluded that Reciproc and WaveOne demonstrated better results as compared to other systems.

In our study, K-file showed least ink removal in coronal and middle third of the root canal. 0.02 taper and poor cutting efficacies could be the reasons.

In the current study, rotary system showed better results than the manual instrumentation which can be attributed to convex triangular cross section, of ProTaper instruments that reduce the contact areas between the file and the dentin. The greater cutting efficiency inherent in this design has been safely improved by balancing the pitch and helix angle that prevents the instruments from inadvertently screwing into the canal. With a negative rake angle, the ProTaper system works with an active cutting motion that substantially increases the effectiveness of the system and reduces torsional strain. [23]

With no literature available for the use of WaveOne file system in primary tooth, we followed the manufacturer's instructions for preparation of the root canal. Primary file (0.06 taper) was selected by considering primary molar root canal morphology. WaveOne showed better results which can be attributed to the reciprocating motion, reverse cutting action, modified convex triangular cross section at the tip end and a convex triangular cross section at the coronal end. [24] This design improves the overall flexibility of the instrument. The tips are modified to follow canal curvature accurately. The variable pitch flutes along the length of the instrument improves safety considerably. [20]

The advantages of the reciprocating motion are based on the physics' law of action and reaction applied to root canal instrumentation, which results in a balanced force. [20] To overcome the root curvature, 'balanced forced technique' was proposed by Roane et al.[25] The reciprocating movement minimizes torsional and flexural stresses, increases the canal centering ability, and reduces the taper lock within the number of instrument cycles within the root canal. [20]

Preparation time is dependent on the technique, operators' experience, number and type of instruments used. [26],[27] In the present study, the preparation time included active instrumentation as well as the time required for changing instruments, cleaning the flutes of the instruments and irrigation of the canal. [1],[4],[9],[13] In this study, the manual instrumentation consisted of four instruments to prepare the canal to ISO size of 30 whereas ProTaper system consisted of two instruments and WaveOne was a single file system. There was a significant difference in the mean preparation time between all three file systems (P < 0.0001). WaveOne required significantly less time (2.37 minutes) for preparation of root canals than preparation with ProTaper (3.78 minutes) and K-file (6.22 minutes). These results are in agreement with previous reports given by the Beurklein et al., [27] which was carried out in permanent teeth.

 Conclusion



Rotary (ProTaper) and reciprocating (WaveOne) systems showed significant difference in cleaning ability in the coronal and middle third of the primary molar root canal as compared to manual instrumentation (K-file). All three file systems clean the apical third of the root canal effectively and efficiently yet there was not much difference between the files in cleaning efficacy at the apical third. While considering the coronal and middle third of the root canal, WaveOne's cleaning ability was the best amongst the three file systems. Also, while evaluating the instrumentation time, WaveOne (reciprocating system) took less time than the other two file systems.

The studies available regarding the superiority of any given type of file in cleaning root canals in primary teeth are selectively few; hence further research should be carried out to evaluate the effectiveness of different kinds of rotary and reciprocating systems in primary teeth.

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