Pediatric dentists’ preference on usage of hand iles or rotary iles for pulpectomy of primary molars-A retrospective study

Akshaya K*1, Vignesh Ravindran1, Senthil Murugan Pandurangan2 1Department of Pediatric and Preventive Dentistry, Saveetha Dental College & Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India 2Department of Oral and Maxillofacial surgery, Saveetha Dental college & Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India


INTRODUCTION
One of the foremost important concerns in pediatric dentistry is a loss of necrotic primary molars resulting in space loss. Clinical success occurs when the tooth is painless, irm, non-mobile, and with no signs of in lammation or infection. Radiographically, lesions should be resolved within six months, and no pathologic root resorption should be observed. (Thomas, 2010). The preliminary concept of biomechanical preparation of the root canal system is removing soft and hard tissue, providing space for irrigants, intracanal medicaments and subsequent obturation (Thomas, 2010).Thus, the success of pulpectomy depends on the elimination of irritants by means of cleaning and shaping the root canal (Yang et al., 1996).
Root canal preparation is performed with burs, iles, reamers, sonic instruments or mechanical apparatus, and with nickel-titanium rotary ile systems. Since most hand preparation techniques are timeconsuming and might cause iatrogenic errors (i.e. lodging, zipping, canal transportation and apical blockage), much attention has been directed toward preparation techniques with Ni-Ti rotary instruments (Walton and Torabinejad, 2002). Rotary instrumentation in curved molar root canals of permanent teeth had been shown to be time-ef icient, with increased patient comfort and lower risk of a lare-up (Zarrabi et al., 2006;Bhagwat and Mehta, 2013). Nickel-Titanium iles don't need precurvature because of their elastic memory; they're motoractivated and should prepare the root canal with high speed (Kosa et al., 1999;Coleman et al., 1995). Despite the advantages of rotary instrumentation and studies performed on primary molars, there aren't any clear guidelines or instructions for the suitable preparation technique of these teeth. Barr et al. used Nickel-Titanium Pro ile ® 0.04 taper rotary instruments for primary root canal preparation and concluded that the use of Nickel-titanium rotary iles for root canal preparation in primary teeth was cost-effective and rapid, resulting in a consistent uniform and predictable obturation. Panchal et al., in 2019, stated that the Pediatric rotary iles Kedo-S had better obturation quality in minimum instrumentation time (Panchal et al., 2019).Also, Nair et al. assessed the postoperative pain after pulpectomy with different iles systems and concluded that the least post-operative pain was found in Mtwo group followed by Kedo-S group and K-ile group (Nair et al., 2018).
However, most of the primary molar root canals are ribbon-shaped. Little is known about the preference of the dentists on the usage of rotary and hand iles among pediatric patients (Mohammed et al., 2017).Thus the aim of the current study Is to qualitatively and quantitatively analyse the preference of pediatric dentists at Saveetha dental college in using rotary and hand iling techniques during pulpectomy procedures in primary molars.

MATERIALS AND METHODS
This was a retrospective study conducted under a university setting.
This study had advantages of easy access to the software, large data availability yet also had disadvantages of smaller sample size and geographic limitation. In the current study, the data of patients who visited the Department of Pediatric and Preventive Dentistry from June 2019 to April 2020 were retrieved from the dental records. Sample size n = 1733. All the case sheets included in the study were approved and veri ied by an external reviewer to avoid errors while recording. Also, Cross-veri ication of data was done with photographs and direct communication with dentists. Pediatric patients of all age groups (from 2 to 12 years) genders (both male and females) with pulpectomy procedures done in primary molars were included in the current study while other pediatric patients without pulpectomy procedures and pulpectomy procedures are done in other primary teeth were excluded from the study. This study has internal validity and no external validity. Data for the study was retrieved. Collected data were tabulated in the excel sheet. This data was then imported to SPSS by IBM after coding. Parametric and non-parametric correlations were done. Following which graphs were made. Nonparametric tests were done by clicking onto legacy dialogue, the chi-square test was run and P-value was determined to verify the signi icance of each of the variables considered and the results were interpreted and analysed statistically.

RESULTS AND DISCUSSION
From the statistical analysis done using SPSS by IBM, it can be well documented that the preference of pediatric dentists was higher in using rotary instrumentation technique for pulpectomy of primary molars (85.7%) than hand iling. P-value is 0.00 (less than 0.05) and is statistically signi icant ( Figure 1). The commonest age group for which the rotary instrumentation technique was preferred the most was between 2 to 5 years (67%). P-value is 0.00 (less than 0.05) and shows statistical signi icance ( Figure 2). Rotary instrumentation technique was preferred the most among male pediatric patients (57.2%) than female patients (42.9) with P-value greater than 0.05 showing statistical insigni icance. This insigni icance can be attributed to smaller sample size and unbiased data considered ( Figure 3). Also, Rotary instrumentation technique was preferred the most while performing pulpectomy in mandibular molars(67.1%) followed primary maxillary molars (32.2%), with P value less than 0.05 showing statistical signi icance (Figure 4).
With regard to the type of instrumentation technique, higher preference was towards rotary instrumentation systems for pulpectomy of primary molars (85.7%). P-value is less than 0.05 and shows statistical signi icance. It is thus suggestive of better properties of rotary iles over hand iling systems. This study is in concordance with the study conducted by Govindaraju et al., in 2017, who stated that 50% of practitioners used Rotary instrumentation technique for a root canal in pri-   mary teeth (Govindaraju et al., 2017c). Similar results were shown by sageena George et al., in 2016(George et al., 2016 and Negar mokhtari et al. in 2017 (Mokhtari et al., 2017). The highest Preference towards rotary iling systems can be attributed to its better properties over hand iling. Nickel-titanium iles for root canal preparations are cost-effective, faster, gives consistently uniform and predictable illings (George et al., 2016;Packiri, 2017).
In pediatric dentistry, the duration of the treatment is essential in decreasing the anxiety among children. Shorter duration Increases trust, decreases anxiety, thus rendering optimal treatment protocol. One of the previous studies has reported decreased chairside time with rotary instrumentation than with hand Instruments (Sharma et al., 2019).Lavanya Govindaraju et al. in 2017 stated that the use of rotary instrumentation in primary teeth results in a marked reduction in the instrumentation time and improves the quality of obturation (Govindaraju et al., 2017b). Similar indings have also been reported by other studies both In vivo and In vitro. Rotary Instrumentation reduces dexterity, thereby increasing the ef iciency of the operator (George et al., 2016). This will be the possible reason for reduced instrumentation time. This Rotary system uses a progressively increasing taper. The previous study has reported restricted apical preparation and higher cervical enlargement with progressive taper than a constantly ixed taper (Bergmans et al., 2003). This will be the rationale for better obturation quality with the progressive taper rotary iles as compared to ixed taper hand iles (Jeevanandan and Govindaraju, 2018). One more reason for better obturation quality with rotary iles as compared with mechanical hand iles are often because of the employment of Nickel-titanium material, which increases the pliability of iles (Govindaraju et al., 2017a). This aids in a better adaptation of iles to root canal curvature, instead of increased transportation and zipping as in Hand iling (Tan and Messer, 2002). Another factor which may provide better preparation with rotary iles is that the wider enlargement and more conical preparation (Govindaraju, 2017).
Preference of Rotary based on age was higher among pediatric patients of age 2-5 years (67%) followed by 6-12 years (32 %). This was in accordance with the study conducted by B.O. Poopala et al. in 2018(Popoola et al., 2018. The reason could be attributed to features of the Rotary Instrumentation technique. Rotary is less time consuming thus enhances better cooperation and diminished tiredness in pediatric patients (Jeevanandan, 2017). In the primary dentition, dental caries was found to be the commonest reason for endodontic treatment with a peak age range of 6-9 years (Subramanyam, 2018). This inding is similar to those reported in previous studies where at the time of presentation of the carious lesion, it would require advanced endodontic interventions (Ukeje et al., 2000). The study Deepa Gurunadhan et al., in 2016 proved the presence of elevated dental neglect score among the parents who resided in the suburban environment, whose educational quali ication was minimum and who have not availed any dental service for >3 years. A higher DMFT and debris index scores were seen in the higher dental neglect group (Gurunathan and Shanmugaavel, 2016).
Rotary instrumentation techniques were highly preferred among male pediatric patients (57.2%) than female patients ( 42.9%). This study result was similar with the study conducted by B.O. Poopala et al., in 2018. He concluded that among those who had endodontic treatment, 51% were males while 49% of them were female patients (Popoola et al., 2018). More male patients had endodontic treatment on account of trauma (Ravikumar et al., 2017) while female patients had endodontic treatment on account of caries. This disparity may be due to the fact that Male children are more physically active hence are highly susceptible to fall and other forms of injuries while female children are more prone to dental caries due to excessive snacking on a cariogenic diet, genetic predisposition associated with AMELX gene (Kaiser and East, 1940). Fluoride ions replace hydroxyl groups in the formation of the apatite crystal lattice resulting in a stronger, luoridated tooth mineral ( luorapatite) which is more resistant to demineralisation hence helps in controlling caries (Somasundaram et al., 2015;Ramakrishnan and Bhukri, 2018).
Rotary Instrumentation technique was highly preferred during pulpectomy procedures of mandibular molars (67.1%) than primary maxillary molars (32.2%). This result was in accordance with a study conducted by Ahmetoglu et al., in 2015(Ahmetoglu et al., 2015 which suggested that rotary was highly used in primary molars (93%). Rotary iling is signi icantly used in primary molars due to unpredictable canals and canal morphology, curved roots and ribbon-shaped root morphology (Christabel, 2015). Rahman. S. S in 2012, stated that more mandibular primary teeth had endodontic treatment relative to the maxillary teeth. This is often in agreement with other studies. This susceptibility of the mandibular teeth to caries could also be related to the relative ease of food lodgement and plaque accumulation in the mandibular posterior region (Rahman et al., 2010). Thus, as a dental clinical practitioner, it is vital to bring awareness among pediatric patients and parents about the importance of proper brushing techniques and maintenance of good oral hygiene . (Govindaraju and Gurunathan, 2017) With the current study as a platform, better instrumentation technique can be identi ied and will enable dentists to gain a thorough knowledge on the pros and cons of different instrumentation techniques for pulpectomy of primary molars. Limitations of this study include Geographic limitation as predominantly South Indian population were only considered and was a Unicentric study with few Incomplete and unclear data. The Future scope of this study will yield a better and more accurate result when different ethnic populations are considered.

CONCLUSIONS
Within the limitation of the present study, Pulpectomy was highly done in Male pediatric patients primarily among the age group of 2-5 years. With regard to the preference of instrumentation technique for pulpectomy of primary molars, Rotary iles were highly preferred by pedodontists, predominantly in male patients among the age group of 2 to 5 years primarily in mandibular molars. Thus, as a clinician, it is important to determine a better instrumentation technique for pulpectomy procedures in primary molars, taking into consideration all the in luencing factors.