An Observational Study on the Materials and Techniques Commonly Adopted by Pediatric Dentists for Single Visit Pulpectomy

The outcome of an endodontically treated primary tooth is affected not only by the biomechanical root preparation and disinfecting solutions, but also by the biocompatibility and resorbing properties of the obturating materials used through techniques that provide adequate fill and adherence of the material. The aim of the study is to recognise the most preferred obturating material and technique used by pediatric dentists for single visit pulpectomy. A total of 2496 pulpectomy procedures were obtained by reviewing case sheets and were analysed using descriptive statistics on SPSS Software. Among 2496 procedures, 96.6% utilised Metapex as the obturating material and 77.5% employed condensation technique for obturation. Metapex was the most common obturating material used and condensation technique was the preferred technique by which primary root canals were filled by pediatric dentists for single visit pulpectomy.


INTRODUCTION
Early childhood caries (ECC) is still one of the prevailing chronic diseases affecting children around the globe. ECC not only affects a child's oral health but also their overall general well being and can also be in luenced by parents' attitude. (Naidu et al., 2016;Gurunathan and Shanmugaavel, 2016) Early Childhood caries may be de ined as the presence of one or more decayed (cavitated or non cavitated lesions), missing(due to caries) or illed tooth sur-faces in any primary teeth in a child 71 months of age or younger. Initiation and progression of caries is altered by immunological defense mechanism present in saliva. Recently, saliva has been used as a biomarker for the detection of free radicals and subsequent caries formation. (Subramanyam et al., 2018) Root canal therapy was advocated around 1932 and its aim is to preserve deciduous teeth where pulpal tissue is affected by caries due to microbes or pathology (Packiri, 2017), trauma (Ravikumar et al., 2017) or other causes (Christabel, 2015) in a functional state until they are replaced by permanent teeth. For primary teeth which demonstrates chronic in lammation or necrosis beyond coronal pulp, pulpectomy is the preferred treatment. (Jeevanandan, 2017). Cleaning and shaping of the root canal is an important step in pulpectomy. (Govindaraju et al., 2017b) With the introduction of rotary endodontics, the overall instrumentation time for pulpectomy has reduced, increased quality of obturation with a bene icial consequence of improved child behaviour. (Govindaraju et al., 2017c,a;Jeevanan-dan and Govindaraju, 2018) Hence, the primary teeth act as natural space maintainers, (Nair et al., 2018) capable of normal masticatory functions and esthetics, preserve the arch length, prevent aberrant tongue habits and speech alterations. (Panchal et al., 2019) However, the complex root morphology of deciduous teeth makes it dif icult to achieve suf icient disinfection by endodontic therapy utilising chemo-mechanical instrumentation. (Govindaraju et al., 2017b) The optimal requirements of a root illing materials are: It should not be soluble and must not cause irritation to the pulpal tissues, should have resorbable property equivalent to physiologic root resorption, be radiopaque and should not set to a hard mass which could de lect an erupting succedaneous tooth. Until now, in spite of numerous investigations involving novel combinations of obturating materials, none have been acquired to exhibit the requisite properties of an ideal agent. The success rate is de ined by a luid tight seal of the obturating material as well as that of the inal restoration to prevent reinfection. Maintenance post-procedure can also be essentiated through the usage of luoride in the form of drinking water (Somasundaram et al., 2015) and toothpastes (Ramakrishnan and Bhukri, 2018) and by adequately following oral hygiene instructions. (Govindaraju, 2017) Zinc oxide eugenol has been used as a root illing material as early as the 1930's and is considered as the gold standard. However, owing to its many drawbacks in regard to its antimicrobial and resorbing properties, alternative materials containing iodoform, calcium hydroxide or a combination of both have been investigated. Iodoform, despite its non-esthetic property, provides suf icient disinfectant action. (Mortazavi and Mesbahi, 2004) In combination with calcium hydroxide, is responsible for superior antimicrobial effects. Endo las, a novel material, has the advantage of resorbing only the extruded apical material and does not undergo hollow tube effect overcoming one of the major detrimental effects of calcium hydroxide.
The different obturation techniques of illing the canals includes conventional manual condensation by pluggers, disposable syringe technique, pressure syringes, navitips, lentulospirals etc. Previous literature quotes that disposable syringe is a simple method which amply ills the canal space. The lentulospiral is an easy and effective tool. It is of two types, namely manual lentulo spiral or mounted on a micromotor handpiece. However, the compact illing has much reliance on adherence of the material to the walls. So far, no obturation techniques have been found ideal for obturation of root canals in primary teeth.
The aim of this study is to infer the most preferred obturating material and technique used by pediatric dentists of a private dental college so as to achieve adequate root illing for a single visit pulpectomy.

METHODOLOGY
The observational study was conducted in the Department of Pediatric and Preventive Dentistry, during the period of June 2019 to March 2020. The ethical approval for this study was obtained from the Institutional Ethical Committee. The data collection was based on treatment procedures performed by the postgraduate students of the Pediatric Dentistry Department.
The inclusion criteria involves pulpectomies performed by the pediatric dentists in children aged 2-10 years old with the diagnosis of irreversible pulpitis. Procedures performed by undergraduates, those pulp therapies other than pulpectomy and procedures performed on special children and those with medical history were excluded from the study. The obturating materials used in this study for pulpectomy procedures were Zinc oxide eugenol, Metapex and Endo las.
Data required for the study was obtained by reviewing 86,000 patient case sheets. Of which, records pertaining to children aged 2-10 years and those undergoing pulpectomy procedures were speci ically analysed to extract data for this study. The obturating materials used for primary teeth pulpectomy were Metapex, Zinc oxide eugenol and Endo las in two techniques namely, condensation and pressure syringe. This collective data was imported into Statistical Package for Social Sciences Software (SPSS) for data analysis. A total of 2496 pulpectomy procedures were included. Any incomplete data was excluded. The internal and external validity of the study is high by generalising the results to the Chennai city population. The obtained data was analysed using descriptive statistics on SPSS Software by IBM and the results were represented graphically.

RESULTS AND DISCUSSION
A total of 2496 pulpectomy procedures were analysed using Descriptive statistics on SPSS version 23.0 based on the obturating materials and techniques utilised. The study samples included pulpectomy procedures performed on 1460 males (58.5%) and 1036 females (41.5%) [ Figure 1]. 72.2% of the participants belonged to the age group of 2-5 years, whereas 27.8% belonged to 6-10 years of age.[ Figure 2]   Figure 4] The application of Metapex as an obturating material was independent of gender and age group. [ Figures 5  and 6] Chi-square test was performed to associate gender and the obturating material used and to correlate the obturating technique used for Metapex obturation. p < 0.05 was found to be statisti-     cally signi icant. A greater number of root canals were obturated using metapex through condensation technique compared to pressure syringe technique.[ Figure 7] Figure 1 shows, 58.5% of children were males and 41.5% were females. Figure 2 shows, 72.2% belonged to 2-5 years of age and 27.8% belonged to 6-10 years of age. Figure 3 shows, 96.6% preferred Metapex, 1.6% preferred Endo las & 1.9% preferred Zinc oxide eugenol. Figure 4 shows, 77.5% preferred condensation technique, while 22.5% preferred pressure syringe technique. Figure 5 shows, there is an increase of use in Metapex in both gen-ders. Chi-square test was performed. (p-value = 0.025). Figure 6 shows, there is an increase of use in Metapex in all the age groups. Chi-square test was performed. (p-value = 0.13). Figure 7 shows, there is an increase of use in Metapex in condensation technique compared to pressure syringe. Chisquare test was performed. (p-value = 0.01) An indifferent attitude towards treatment of irreversible pulpitis of deciduous teeth can cause damage to the succedaneous tooth such as enamel hypoplasia or hypomineralisation and produce a negative impact on the quality of life of a child (pain, missed school days, dif iculty in mastication). Such teeth must be subjected to either extraction or root canal treatment. Primary teeth with pulpal necrosis are polymicrobial in nature with a dominant activity of anaerobic bacteria residing deeply in dentin and cementum around the periapex. (Pinky et al., 2011) The rationale of pulpectomy includes the removal of irreversibly in lamed pulpal tissue by biomechanical root preparation following of root canals with a suitable material that resorbs at the same rate as the physiologic root resorption and that which can be eliminated if accidentally extruded through the apex. However, micro organisms in the ins and isthmus can remain even after adequate preparation and debridement. Owing to this risk, and the proximity of the succedaneous tooth to the primary root, the obturating material must be biocompatible and antimicrobial. It must be able to neutralise toxic products and prevent canal reinfection to create a favourable environment for healing to take place.
Until 2008, Zinc oxide eugenol was explicitly recommended in clinical guidelines developed by American Academy of Pediatric Dentistry. But Zinc oxide eugenol is not considered ideal as it presents with limited antimicrobial action and it tends to resorb at a rate slower than the roots of deciduous teeth. (Mortazavi and Mesbahi, 2004) It is also known to irritate the periapical tissues, cause necrosis of bone, cementum and alter the path of eruption of the succedaneous tooth when extruded beyond the apex. Later on, based on studies the AAPD guidelines began to cite iodoform based pastes as a suitable alternative to zinc oxide eugenol. (Soleiman, 2015) Iodoform is used either in pure form or is combined with other materials. It is a potent bactericidal, non -irritant, radiopaque, and well suited for a non-shrinking and non-soluble paste. Different combination of iodoform are available: KRI paste (Iodoform, camphor, menthol, para-chlorophenol), Vitapex/Metapex (calcium hydroxide 30.3%, iodoform 40.4%, silicone oil 22.4%, others 6.9 %.), Endo las (Zinc oxide eugenol -56.5%, barium sulfate -1.63%, iodoform -40.6%, calcium hydroxide -1.07%, eugenol, and pentachlorophenol). Calcium hydroxide is considered to have potent antimicrobial action primarily due to liberation of hydroxyl ions and inactivation of enzymes in the bacterial cytoplasmic membrane. It is easily resorbed when inadvertently forced beyond the apex. In this study, zinc oxide eugenol as well as iodoform combination obturating materials were used and among which the most preferred material was sought after.
In our study, a wide age range was selected; 2-5 years old (72.2%) and 6-10 years (27.8%). This was taken to consider a complete primary dentition (2-5 years) and a mixed dentition phase (6-10 years) for obturation. Metapex was the most common material used (96.6%). Metapex are available in preformed syringes which can be directly placed into the canals and the materials are extruded by simple pressure. Pastes containing an oily vehicle promote the lowest solubility and diffusion. Metapex, being an oil based vehicle, has enhanced luidity and permeability, which improves the collateral bene it of root canal illing. It has a slightly faster rate of resorption than that of the deciduous teeth. This resorption may cause voids within the canal leading to the formation of hollow tube defects. (Al-Ostwani et al., 2016) Metapex was more effective than zinc oxide eugenol because it produced a greater decrease in abnormal tooth mobility and pre-existing bone radiolucency. (Mortazavi and Mesbahi, 2004) Metapex had no toxic effect on permanent successors, and was radiopaque. This calcium hydroxide iodoform mixture to be a nearly ideal pulpal illing material for primary teeth. (Basir et al., 2019) Zinc oxide eugenol was preferred less (1.9%) maybe due to its disadvantages such as retaining the illed material and its in luence on the succedaneous teeth (enamel defects on permanent incisors). A study by Sadrian and Coll re lected a mean time of 50 months for zinc oxide eugenol resorption. They advised a ill short of the apex than at/beyond the apex to avoid retention. A recent retrospective study by Bahrololoomi and Zamaninejed concluded that pulpectomy of primary molars using zinc oxide eugenol was one of the most reliable and successful treatments.
A novel material named Endo las was the least utilised in our study (1.6%). The combination has been made to overcome the disadvantages of combining materials. This material is hydrophilic and adheres to root canals. It has a broad spectrum of antibacterial activity and disinfects even accessory canals. It resorbs at the same pace as the physiological resorption of the primary root. The resorption is limited to excess extruded material and it is not depleted intra-radicularly. Endo las has high clinical as well as radiographic success over zinc oxide eugenol.
The common observation technique used was condensation (77.5%) even when Metapex was the common obturating material used. Metapex usually adopts the pressure syringe technique. This may be due to the opinion that condensation is the easier method which does not require additional equipment and the plugger pressure provides adequate low. However, Metapex through a pressure syringe is shown to result in good quality of obturated canals. Condensation technique may be used for zinc oxide eugenol with a ill adequacy of 57%. Endo las may be best employed with lentilospiral and has a ill adequacy of 64.5% In a study by Khubchandani et al, the highest number of voids were seen in canals illed using lentulo spiral (20%). This is contradicting with earlier studies by Torres et al. and Memarpour et al. who found that the lentulo spiral ills the root canals better than syringe technique. Available injection techniques provided by literature have a universal defect, which is the overilling of the obturating material that leads to in lammation and related complications.
However, all the techniques used to ill the root canals tended to form voids according to previous literature. The voids may produce microleakage in the paste leading to microorganism regrowth, reinfection and an increased risk of post-operative symptoms, especially if there are several large voids. Factors that in luence the location and size of the voids include the type, viscosity, and consistency of the paste, the method used to apply the paste, and operator skill and experiences.
The merits of the study are its enormous sample size and it allows the need to procure novel and better materials for pulpectomy for the greater good irrespective of cost and handling characteristics. The limitations of the study include it's restricted geographical location and the usage of available and cost-effective materials. Future studies may aim for a larger sample size involving different geographical locations which would yield satisfactory results.

CONCLUSIONS
Within the limitations of the study, Metapex was the preferred obturating material of choice by paediatric dentists for single visit pulpectomy. However, it was preferred to be used through condensation technique owing to the easy maneuverability of the material obtained through this technique.