Comparison Between Manual and Rotatory Instrumentation Pulpectomy Treatments in Primary Mandibular Molars

Introduction

Dental caries is a prevalent chronic disease, affecting 60-90% of school-age children in industrialized countries; although in the last four decades the prevalence and severity of caries lesions have decreased, it is still a frequent disease for this age group. The American Dental Association (ADA) classifies dental caries by clinical presentation as initial, moderate, and severe; furthermore, the ADA classifies the disease using the international caries detection and diagnosis system (ICDAS II; International Caries Detection and Assessment System II) and by a radiographic presentation of the proximal faces based on the E0-E2, D1-D3 notation system. Within the non-vital pulp treatments, pulpectomy is indicated in temporary teeth; pulpectomy is a conventional endodontic treatment for teeth with exposed, infected, and/or necrotic tissue to eliminate pulp and periradicular infection.

In a recent systematic review that compared three different strategies for the management of deep caries lesions (i.e. complete caries removal, selective caries removal, and step caries removal), Aïem and colleagues (2020) report an increased restoration failure risk when selective removal is used compared to complete removal of caries. In a study where French dentists were surveyed on the management of deep caries lesions in primary dentition, the majority of respondents mentioned performing deep caries removal in a single step. Endodontic procedures in the pediatric population can assist to keep temporary teeth until exfoliation, which is a key principle of pediatric dentistry. Vital pulp and non-vital pulp treatments are employed in the treatment of severe lesions and deep caries; meanwhile, pulpectomy is a treatment largely used in the primary dentition. In pulp therapy, a pulpotomy is performed by removing the pulp from the chamber, while in a pulpectomy, all the tissue from both the chamber and the root canals is removed.

There are two parameters used to determine root canal treatment success: 1) the morphology and shaping of the canal; and 2) the duct cleanliness or the adequate level of disinfection provided by the type and quantity of intra-canal irrigation (e.g. chlorhexidine, sodium hypochlorite, citric acid, profuse irrigation). A pulpectomy is the technique of choice for primary dentition in deep carious lesions with pulp necrosis since pulpectomy has a higher success rate than pulpotomy. While the time for access to the root canal is less with the use of rotary instrumentation systems compared to a manual technique, manual techniques have the same efficacy as rotary systems in root canal cleaning procedures. Rotary systems have greater clinical success compared to manual techniques, in addition to having advantages in instrumentation time, canal shaping, reduction in working time, better cooperation and less patient fatigue, improvement in the conicity of the root canal, and promoting a higher quality of obturation. In a recent meta-analysis, Manchanda and colleagues (2020) conclude that rotary instrumentation has similar clinical and radiographic success rates to manual techniques in primary dentition; additionally, rotatory techniques show lower levels of postoperative pain and less instrumentation time. In the only study in the Mexican population that compared a rotary system (i.e. K3) against a manual technique (i.e. K-file) it was found that the instrumentation and obturation time was shorter, being a promising technique in children.

Given the limited comparative literature about rotatory techniques used in pulpectomy treatment, it is necessary to conduct clinical trials that compare both manual and rotatory techniques in first dentition treatment. So far, studies have been carried out comparing rotary systems designed for adults in the pediatric population. Recently, interest to validate and implement safe and effective protocols for the management of rotary systems in primary dentition has emerged in pediatric dentistry. Below is a protocol designed to investigate the advantages and disadvantages associated with the use of rotary systems designed for our population of interest.