An In Vivo Evaluation of Postoperative Pain after Root Canal Instrumentation Using Manual K-files and Kedo-S Rotary files in Primary Molars

ABSTRACT

Aim:

To determine postoperative pain after root canal instrumentation using manual K-file and rotary Kedo-S files in primary molars.

Material and Method:

Thirty-six primary mandibular molars from 4- to 8-year-old children requiring pulpectomy were randomly split into two groups of 18 teeth each, that is, manual file K-file (Group I) and Kedo-S rotary file (Group II). Children’s pre- and postoperative pain was assessed using a four-point scale at different time intervals.

Results:

From the result of the present study, it was observed that the Kedo-S group showed significantly less pain after 24, 48, and 72 h.

Conclusion:

It was concluded from the present research that patients enrolled in the Kedo-s group experienced less pain.

INTRODUCTION

Pulpectomy is still the initial line of treatment for primary teeth with pulpal disease. The purpose of the procedure is to protect the afflicted periapical tissue and save the teeth until their long-term replacements can erupt. The primary objective of root canal instrumentation should be to remove infectious dentine, necrotic pulpal tissue, and debris to get rid of infectious microorganisms. Both the materials used and the concepts underlying equipment procedures have been the subject of extensive research in the development of pediatric endodontics.[1]

The main elements that affect pulpectomy success are instrumentation of the root canals, irrigation, cleaning, and obturation. Root canal shape and cleaning maintain the root canal’s structural integrity while eradicating bacteria and removing infected pulp chamber content. Even though hand filing is the preferred technique of instrumenting primary root canals, it has some drawbacks, including longer canal preparation times, unequal root canal space preparation, and other iatrogenic mistakes.[2]

To surmount these limitations, the use of Ni-Ti instruments was recommended. For thirty years, permanent teeth have been treated successfully with rotary instruments. They are faster, more flexible, and more shape memory than stainless steel files, and this leads to better cleaning results with shorter chair side times. Barr and associates first used the NiTi file system in pediatric endodontics in the year 2000.[3]

Dr. Ganesh Jeevanandan introduced “Kedo-S” pediatric rotary file system in 2016. It is one of these rare pediatric rotary instrumentation systems. Having an overall length of 16 mm and a functional length of 12 mm, it is made up of three NiTi files (D1, E1, and U1). According to reports, the taper on these files is variably variable. D1 file has a tip diameter of 0.25 mm and used in primary molars with narrow canals. E1 is designed for broader molar canals and has a tip diameter of 0.30 mm. Primary incisor teeth can employ U1, which has a tip diameter of 0.40.[4]

More studies are recognizing the importance of reducing postoperative discomfort in pediatric endodontics employing motorized instruments and particular pediatric rotary files. Hence, the objective of the present investigation was to determine postoperative pain after root canal instrumentation using manual K-file and rotary Kedo-S files in primary molars.

MATERIAL AND METHOD

To compare the effectiveness of manual K-files and Kedo-S rotary files for pulp canal therapy in primary molars, an in vivo clinical trial was designed. Totally, 36 primary mandibular molars from children aged between 4 and 8 years requiring pulpectomy were assigned. Subjects with scores of 3 or 4 on the Frankel’s behavior rating scale, no anatomical defects, no analgesic use within 12 h, no history of systemic conditions, and having two-thirds of the roots with minimal root angulation were all taken into consideration for the study. Children with special healthcare needs, children with Frankel’s behavior rating scales 1 and 2, sinus tract, acute alveolar abscess with pus discharge, non-restorable tooth, root caries, cracked teeth, physiologic mobility, pulpal pathology, root canal calcification, severe root angulation, root length less than two-thirds, and teeth with pulp necrosis were among the conditions that were excluded from the present trail. All 36 primary mandibular molars from included children were randomly assigned in into two groups of 18 teeth each in manual file K-file (Group I) and Kedo-S rotary file (Group II).

After the complete clinical and radiographic assessment, the tooth was anesthetized by means of 2% lignocaine hydrochloride (Lox*2%, Neon Laboratories Ltd) with 1:200,000 adrenaline. After achieving profound anesthesia, the tooth was isolated by rubber dam, subsequently caries removal and access were gained.

Initially, canals were negotiated by size #10 K-file to determine the patency of the canal following to that working length was established using a radiographic technique.

For Group I (N = 18), teeth were instrumented utilizing the balanced force technique and k-files (Mani files, Japan) up to #35 size.

In group II (N = 18), in rotary Kedo-S file group the patency of the canal was achieved with a taper No. 15 size followed by No. 20 size stainless steel K-file used in the quarter-pull turn method. The mesiolingual and mesiobuccal root canals were instrumented using a D1 rotary Kedo-S file system (Reeganz Dental Care Pvt. Ltd.), and the distal canal was instrumented using E1 rotary Kedo-S file system as per manufacture instruction.

During root canal preparation, the canals were irrigated with one mL of 3% sodium hypochlorite (NaOCl) during instrumentation. Following canal preparation, saline was used to flush out any traces of NaOCl. The canals were dried with sterile absorbent paper points, and the Metapex (Meta Biomed Co. Ltd, S Korea) was used to obturate the canals by inserting the tip inside the canal and filling the canal from the apex to the orifice with the obturating material. Post-obturation restoration was done by glass ionomer cement and subsequent restoration with stainless steel crown. Post-treatment pain assessment at 6, 12, 24, 48, and 72 h was recorded via a telephonic conversation with the parents. Four-point scale was used to assess postoperative pain which was previously used by Topçuoğlu and colleagues [Figure 1].[5] Data were collected, and statistical analysis was performed to compare pain scores of two groups using Student’s t-test.

Figure 1.

Four-point scale

RESULT

The study design includes 36 children, with 18 (50%) boys and 18 (50%) girls. Regarding the baseline variables (age, participant distribution), there were no statistically significant differences between the groups in the study population [Table 1].

Table 1.

Demographic data of study population

Parameters	Group I (K-file)	Group II (Kedo-S)	P
Girls	8	9	>0.05
Boys	10	9	>0.05
Mean age	6.45±0.45	6.30±0.40	>0.05

The intergroup comparison in Table 2 reveals a significant difference between the groups, with post-treatment pain in the K-file group being higher than in the Kedo-S group (p 0.05).

Table 2.

Intergroup evaluation of mean pain score at different time intervals

Time	Groups	Mean Pain Score	t	P
Preoperative	I	2.75±0.22	1.01	>0.05
	II	2.78±0.29
After 6 h	I	2.62±0.28	1.15	>0.05
	II	2.59±0.32
After 12 h	I	2.08±0.21	1.49	>0.05
	II	2.04±0.23
After 24 h	I	1.88±0.32	2.44	<0.05*
	II	1.34±0.33
After 48 h	I	1.26±0.30	2.38	<0.05*
	II	1.01±0.27
After 72 h	I	0.95±0.18	2.45	<0.05*
	II	0.25±0.10

*Significant (P < 0.05)

DISCUSSION

Pulpectomies are performed with the primary and ultimate goal of stopping additional tooth decay and the early loss of primary teeth.[6] For a root canal procedure to be successful, there must be a perfect hermetic seal that prevents bacteria from entering the root canal space. The proper obturation of the root canals and chemo-mechanical preparation remain essential for the clinical effectiveness of pulpectomy.[7] For many years, the root canal instrumentation of deciduous teeth was done manually with K-files. Due to pulp therapy’s ineffectiveness at cleaning the root canals, numerous rotary files were developed and are now widely utilized to create a uniform taper across the root canals.[8]

Evaluation and control of postoperative discomfort are crucial components of root canal therapy since they can affect the child’s ability to behave well. To maintain uniformity, this study only utilized a single-visit pulpectomy.[9,10]

The combination between the host immunological response, infection, and physical damage is a major role in the multifactorial etiology of postoperative pain. Dentinal chips, necrotic debris, bacteria, and irrigation fluid are inexorably driven into the periapical tissues during the chemo-mechanical preparation process.[11] Extrusion of these components into the tissues surrounding the periapex may have unfavorable effects, including the development of inflammation, postoperative discomfort, and a delay in the periapical healing process.[12]

The goal of this in vivo research was to assess post-treatment discomfort subsequently after pulpectomy in primary molars utilizing Kedo-S rotary files and manual K-files. The findings indicate that patients in the hand file group experienced significantly more postoperative pain following pulpectomy than those in the rotary file group.

Ni-Ti rotary files are used in rotary instrumentation, which employs the crown down technique to manage canal preparation in the apical part of the canal and prevent apical ejection of debris.[13] The piston-like motion of using files can be attributed to an increase in debris extrusion while using hand instruments. The present study’s rotary file system includes a variable taper that restricts the canal’s apical preparation while enabling a wider cervical preparation. This element also contributes to the reduced postoperative pain that was observed in the existing study when using a rotary system as opposed to hand instrumentation.[14] Nair M et al. (2018)[15] concluded that less postoperative pain was found in rotary Kedo-S group as opposed to manual K-file group which is in agreement to our study. Similarly, Panchal V et al. (2019)[16] concluded that the Kedo-S file demonstrated considerably less after treatment pain in contrast to K-file and H-file at 6 h and 12 h intervals. However, rotary and hand file groups did not significantly vary at follow-up intervals of 24, 48, or 72 h.

More investigations are required to determine the precise origin of pain, how to measure objective symptoms of pain, and the function of various obturating materials and irrigating solutions.

Clinical significance

Use of the specially designed Kedo-S files for primary tooth root canal preparation lessens the post-treatment discomfort of pediatric patients, which has a more beneficial impact on the behavior of the kids and fosters a positive dental attitude.

Limitation

The absence of a cross-over research design, which would have allowed comparisons of the two groups in a single child, could be seen as a drawback of the current study because it was impossible to implement due to the sample selection’s sensitivity.

CONCLUSION

From the outcome of the current investigation, it can be concluded that after root canal instrumentation of a deciduous molar, the Kedo-S rotary file system caused less postoperative discomfort than manual K-file.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.