Journal of Orofacial Sciences

: 2020  |  Volume : 12  |  Issue : 1  |  Page : 30--34

Comparison Between Three Rotary Files on Quality of Obturation and Instrumentation Time in Primary Teeth − A Double Blinded Randomized Controlled Trial

Sofiya Juliet, Ganesh Jeevanandan, Lavanya Govindaraju, Vignesh Ravindran, Erulappan Muthuganapathy Subramanian 
 Department of Pediatric and Preventive Dentistry, Saveetha Dental College & Hospitals, Saveetha Institute of Medical and Technical Sciences, Velappanchavadi, Chennai, Tamil Nadu, India

Correspondence Address:
Dr. Ganesh Jeevanandan
Department of Pediatric and Preventive Dentistry, Saveetha Dental College, Saveetha Institute of Medical And Technical Science, Kuthambakkam, Chennai, Tamil Nadu


Introduction: There are many available Nickel Titanium (Ni-Ti) rotary systems that are used for canal cleaning and shaping of the permanent teeth. The new emerging concept in pediatric dentistry is the use of rotary files for canal instrumentation in primary teeth. In literature, there are no clinical studies comparing three different rotary systems in primary teeth. The aim of this study was to compare and evaluate the quality of obturation and instrumentation time using three rotary file systems in primary mandibular molars. Materials and Methods: A total of 45 primary mandibular molars were included in the study and were randomly allotted to one of the three groups. Group 1: ProTaper files; Group 2 Kedo-S files and Group 3: RaCe files. Standardized digital radiographs were taken to the assess quality of obturation as underfill, optimal fill and overfill. Statistical analysis was done using SPSS software version 17.0. An intergroup comparison of the quality of obturation and instrumentation time was done using Chi-square test and ANOVA with the level of significance set at 0.05. Results: No significant difference was observed in the quality of obturation among the three groups (P = 0.661). However, a statistically significant was noted in the instrumentation time among the groups (P < 0.05). In Kedo-S files group 80% of the teeth were optimally filled followed by 60% in ProTaper files and 46.67 % in RaCe files group. The instrumentation time was least in RaCe files 31.67 secs followed by ProTaper files 45.93 secs and Kedo-S (78.53 secs). Conclusion: No significant difference was noted with respect to quality of obturation using S2 ProTaper files, Kedo-S files and RaCe files in primary teeth. There was a significant difference in instrumentation time among the three groups with least working time with RaCe files.

How to cite this article:
Juliet S, Jeevanandan G, Govindaraju L, Ravindran V, Subramanian EM. Comparison Between Three Rotary Files on Quality of Obturation and Instrumentation Time in Primary Teeth − A Double Blinded Randomized Controlled Trial.J Orofac Sci 2020;12:30-34

How to cite this URL:
Juliet S, Jeevanandan G, Govindaraju L, Ravindran V, Subramanian EM. Comparison Between Three Rotary Files on Quality of Obturation and Instrumentation Time in Primary Teeth − A Double Blinded Randomized Controlled Trial. J Orofac Sci [serial online] 2020 [cited 2020 Aug 8 ];12:30-34
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Dental caries is defined as an infectious microbial disease of the teeth that results in localized dissolution and destruction of the calcified tissues.[1] Initial caries seen on the tooth surface are white spot lesions which are reversible, followed by brownish discoloration and can lead to cavitation. This untreated dentinal caries can progress to the pulp, causing inflammation of pulp leading to pulpitis. This inflammation that is produced within the rigid confined pulp chamber will produce severe persistent pain leading to necrosis of the pulp tissue.[2] The destruction of the tooth structure due to caries involves almost the entire crown, leaving behind root with limited or no crown portion resulting in extraction of the tooth. [3] The major concerns in pediatric dentistry is the loss of the primary molar leading to space loss. The alternative for managing symptomatic decayed primary teeth is pulp therapy.

Pulpectomy is the procedure that is done to restore the primary teeth and serve as a natural space maintainer. This can be carried out in both single and multi-rooted teeth with signs of furcal involvement. [4] Among the pediatric dentists, endodontic management of primary teeth has become the major treatment procedure. [5] The hand instrumentation done with endodontic broaches and hand files remains the conventional technique for root canal preparation in primary teeth and is time consuming. [6] The major concern of hand instrumentation in deciduous teeth is the increased preparation time leading to limited cooperation of the children. The complexities seen in the root canal morphology of deciduous teeth require improvement in the endodontic instruments to prevent unfavorable complications, like ledges, perforations and transportation during canal preparation. [7]

The rotary instrumentation has been showing increasing results in a safer, faster and better quality of canal preparation. The use of rotary systems by a pediatric dentist insists a thorough training as it reduces the tactile sense of the operator. The use of Nickel Titanium (NiTi) rotary files in primary tooth were first described by Barr et al.[8] The use of NiTi rotary files in root canal preparation for permanent teeth is efficient and effective. [9],[10],[11] The rotary NiTi systems that were used in the permanent teeth have been used for canal debridement and shaping in primary teeth. There are more than 60 NiTi rotary systems available for permanent teeth in the market, which includes ProTaper and RaCe. ProTaper files have become the most commonly used rotary files for effective cleaning and shaping of the root canals in permanent teeth. Consequently, the development of newer rotary instruments is essential to obtain better performance in cleaning and shaping of the root canal in primary teeth. [12] Kedo-S is the file that was customized exclusively for the canal instrumentation of primary tooth with a total length of 16mm. The Kedo-S paediatric rotary files have a variable taper aiding in easy coronal enlargement and safer apical preparation. [13] Race file is unique; it has been designed in a manner to achieve the required apical sizes. The major goal of Race instrument is to achieve apical preparation sizes that are scientifically proven to effectively disinfect the canal. [14]

Hence, the aim of this present study was to clinically evaluate and compare the quality of obturation and instrumentation time using three rotary file systems in primary molars.

 Materials and Methods

This double-blinded randomized controlled trial was conducted in the Department of Pediatric and Preventive dentistry in a private dental college. Ethical approval for this study (SRB/MDS/PEDO/16-17/2) was provided by the Ethical Committee of Saveetha Research Board of Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India, on 19 December 2016. Informed consent was obtained from children’s parents or guardians before participation in the study. Participant’s confidentiality was assured with an identity number and the records were maintained only by the researcher.

A total of 45 children between the age group of 5–8 years requiring pulpectomy in any one of the primary mandibular molars were included in the study. The selected tooth was randomly allotted to one of the three groups where instrumentation was done using: Group 1: ProTaper; Group 2: Kedo-S; Group 3: RaCe. Computer‑generated randomization was used for the allotment of the participants [Figure 1]. The sample size was calculated using a previous study (in vivo) with 95% power using G Power analysis.[15] The children included in the study was based on the following criteria: (a) decayed mandibular primary molars with pulpal involvement and without sinus tract, (b) root apices should closed without both internal and external pathologic / physiologic root resorption, (c) presence of adequate tooth structure for full coronal restoration with Stainless Steel crown. In case if more than one tooth met the eligibility criteria, the tooth number was written down on a paper, folded and placed in an envelope. The child was asked to select one, that tooth was included in the study. Children with limited or lacking cooperative ability, children with any systemic diseases and special health‑care need children were excluded from the study.{Figure 1}

All the dental procedures for the children included in the study were done by a single operator. A full mouth examination was done and intraoral periapical radiographs of the teeth indicated for pulpectomy was taken prior to the initiation of the dental procedure. Once the treatment was planned, 2% lignocaine with 1:200,000 adrenaline was used for local anesthesia (LOX* 2% ADRENALINE, Neon Laboratories limited, India). Every tooth involved in the study for pulpectomy were isolated using rubber dam (GDC Marketing, India).

Using a high‑speed hand-piece and 330 pear shaper bur (Mani, India), clinically visible caries were removed. Complete de-roofing was done. Coronal pulp was amputated using a spoon excavator. The patency of the root canals was obtained using a No. 10 size K‑file. The working length was determined and was kept 1 mm short of the apex. The canal preparation was done till the working length using an X‑Smart motor. (Dentsply India Pvt. Ltd., Delhi, India):Group 1: Only S2 ProTaper file was used till the full working length.Group 2: Kedo-S file D1, E1 was used. D1 file has a tip diameter of 0.25 mm with a variable taper to be used in molars with narrow canals (preferably the mesio-buccal and mesio-lingual canals). E1 file has a tip diameter of 0.30 mm to be used in wider molar canals (preferably for the distal canal).Group 3: Only RaCe file 0.25 tip (4% taper) was used till the full working length.

The instrumentation time was recorded (in seconds) by an assistant using a stopwatch only during the use of rotary systems for the preparation of the canal. The canals were then irrigated with 1 mL of 3% NaOCl followed by saline. Sterile paper points were used to dry the canals. The obturation was done using Metapex, a combination of calcium hydroxide and iodoform paste (Metapex, Meta Biomed Co., Ltd., Korea). The material was gently pushed using cotton pellets. The quality of obturation was assessed by taking a postoperative radiograph. It was assessed by another pediatric dentist who was blinded to the type of instrumentation used for the canal preparation. Intra examiner reliability test for radiographic evaluation was carried out in an independent manner by means of Kappa test (0.90–excellent). The obturation quality was graded as Underfilled (canals with obturating material more than 2 mm short of the apex), Optimal (obturating material at or within 1 mm short of the apex), Overfilled (canals with obturating material beyond the apex) as given by Coll and Sadrian.[16] The tooth was restored with glass ionomer cement (Shofu, Shofuinc. Japan) followed by placement of stainless-steel crowns either on the same day or in the next appointment.

The statistical analysis was done using SPSS software version 17.0. (Chicago, SPSS Inc). Chi‑square test was used for intergroup comparison of quality of obturation among the groups. ANOVA and Post hoc Tukey test were used for the compare the instrumentation time.


A total of 45 children were included, out of which 26 girls and 19 boys participated in the study. The participant’s demographic details of all the groups is tabulated [Table 1]. With respect to the Instrumentation time among the groups, in Group 1 the mean instrumentation time was 45.93 secs, in Group 2 the mean instrumentation time was 78.53 sec and in Group 3 the mean instrumentation time was 31.67 secs. Comparison of instrumentation time was done using ANOVA test and a statistically significant difference was noted between the three groups [Table 2]. Post hoc Tukey analysis confirmed that there was a significant reduced instrumentation time between the three rotary systems (P < 0.001) [Table 3].{Table 1}{Table 2}{Table 3}

In relation to the quality of obturation, a better quality of obturation was seen in KedoS group followed by ProTaper and then RaCe rotary file system. However, no statistical difference in the quality of obturation was noted [Table 4].{Table 4}


This study was a randomized clinical trial comparing three different rotary systems for root canal instrumentation in primary teeth. The objective of root canal treatment is to disinfect the root canal and completely seal the debrided canal.[17] In primary teeth with infected pulpal tissue pulpectomy is the preferred treatment of choice over extraction to preserve function and esthetics.[18],[19],[20] The use of rotary instruments has shown to be faster and to produce well-filled canals and uniform results.[6],[8],[21],[22] The reduction in instrumentation time directly correlates with lesser chair time, which in turn causes a positive impact on child’s cooperation. It has been suggested that rotary instrumentation have a greater apical enlargement capacity, reduces apical transportation and improves root canal shape over traditional hand filling. [23]

Barr et al gave the merits and demerits about the use of rotary files in primary teeth. These authors consider that the use of rotary technique was more effective way to debride the uneven walls of primary root canals and to provide a dense fill.[8] Silva et al.[6] did not find any difference in the cleaning capacity between rotary system and manual instrumentation techniques and concluded that there was reduction in the instrumentation time on using the rotary technique. A study by Crespo et al[24] demonstrated that, the use of rotary files in deciduous teeth were more efficient in both preparation time and root canal shaping, facilitating a greater quality of obturation of the root canal.

In the present study, based on the quality of obturation, there was no statistically significant difference between the three rotary system groups. However, more number of optimally filled canals was noted in Kedo-S group. The optimal filling of the canals in Kedo-S group is due to the greater coronal enlargement produced by the Kedo-S files that helps the obturating material to flow easily inside the prepared canal space. Also, the apical enlargement produced by the Kedo-S file system was minimal thereby avoiding over preparation and extrusion of the obturating material. At the same time maximum number of overfillings was noted primary teeth instrumented with Race Rotary file. This could be attributed to the length and design of the file as it was originally designed for use in permanent teeth. Race file system is designed with alternate cutting edges and triangular cross section with sharp edges which increases the cutting efficiency of the file which could have resulted in increased number of overfillings in the primary tooth making the file not ideal for use according to the morphology of the primary teeth. In the study done by Abbas Makarem et al.[24] and Tania Ochoa–Romero[25] there was a statistically significant difference in the quality of obturation between the manual and rotary files. No difference in the obturation quality was noticed in the present study as the canal instrumentation was done only with rotary files in all the three groups.

However, a significant difference in the instrumentation time was noted between the three groups. The instrumentation time was found to be less with RaCe file followed by ProTaper file system and the Kedo-S rotary system. Using only ProTaper S2 in the primary molar teeth showed reduction in working time with increase in mean canal volume.[26] This was the reason to use only S2 file in the ProTaper group in the current study. Also use of only Size 20 RaCe file showed reduced working time with moderate mean canal volume in the study done by Jeevanandan.[26] So only size 25 of RaCe file was used in the current study to reduce the working time, as well as the tip matched the tip diameter of the files used in the other study groups. In the previous study done by Govindaraju L et al.[27] comparing two different rotary files with manual instrumentation showed that there was no statistically significant difference in the instrumentation time between the two rotary file systems which is completely contradictory to the results of the present study. This can due to the use of single file only for canal preparation in Group 1 and 3, whereas in Group 2, two files (D1, E1) were used to prepare the different canals in the primary molars for sufficient enlargement and removal of infected tissue. Decreased instrumentation time will emphatically influence the behavior of the child resulting in better quality of treatmentFew limitations are present in the current study. First, only the extent of filling was evaluated and presence of voids were not evaluated because the radiographs obtained for assessment were two-dimensional. Using computed tomography (CT) or micro-computed tomography (Micro CT) would give a three-dimensional view of the obturation quality, which could help in assessing the presence or absence of voids. Direct use of larger instruments without sequential use may lead to instrument separation. So careful assessment of the canal patency should be done prior to use of rotary files.


RaCe rotary file showed a significant reduction in the instrumentation time compared to the other two rotary systems but resulted in overfillings hence making them not suitable for primary teeth. Kedo-S rotary file showed better quality of obturation in the primary teeth but was not significant compared to ProTaper and RaCe files.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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