Preservation of primary teeth until their natural exfoliation is a key objective in paediatric dentistry. Primary molars are vital for maintaining arch length, guiding permanent tooth eruption, supporting mastication, and promoting overall oral health. When these teeth are compromised by extensive caries or pulpal pathology, pulpectomy is often the treatment of choice to retain them until natural exfoliation.

Pulpectomy involves the removal of necrotic or irreversibly inflamed pulp tissue, followed by biomechanical preparation, disinfection, and obturation. Among these, biomechanical preparation is crucial for cleaning and shaping the canals and eliminating microbial load. The success of this step is highly influenced by the instrumentation technique used.

Traditionally, stainless steel hand files have been employed for this purpose. While effective, they are time-consuming, technique-sensitive, and often difficult to use in uncooperative paediatric patients due to prolonged chair time. To address these challenges, rotary instrumentation systems which was originally designed for permanent teeth, know have been adapted for use in primary molars. These systems offer advantages such as uniform canal shaping, reduced operator fatigue, and significantly shorter instrumentation time. However, their limited flexibility poses challenges in navigating the narrow, curved canals of primary molars.

Recent innovations like controlled memory (CM) rotary files offer improved flexibility and resistance to cyclic fatigue, allowing safer navigation through complex canal anatomies with less apical debris extrusion. This is particularly important since debris extrusion can lead to post-operative pain, which is a significant factor in a child’s perception of dental treatment.

Despite the increasing adoption of rotary and CM rotary instrumentation in paediatric dentistry, limited clinical trials have directly compared these techniques with conventional hand files in primary molars, particularly focusing on both instrumentation time and post-operative pain. Most available studies are in vitro or observational, underscoring the need for well-designed randomized controlled clinical trials in this area.

This study aims to fill this gap by conducting a randomized controlled clinical trial to evaluate and compare the instrumentation time and post-operative pain associated with hand files, rotary files, and CM rotary files during biomechanical preparation of primary molars in children aged between 8 and 12 years. By assessing both clinical efficiency and patient-centered outcomes, this study seeks to identify the most suitable instrumentation technique for paediatric endodontic practice.

The findings of this study will contribute valuable insights into improving the quality of care, reducing treatment time, enhancing patient comfort, and ultimately supporting better treatment outcomes in paediatric dentistry.