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ABSTRACT Asian populations show many variations in root canal morphology of permanent mandibular first molar. This in vitro study was done at Dr Ishrat ul Ibad Khan Institute of Oral Health Sciences and NED University Karachi, Pakistan to explore the number of roots and root canals, their configurations, occurrence of isthmi and apical deltas in mandibular permanent first molar teeth in Pakistani population. One hundred and twenty three mandibular first permanent molars were collected and exposed to clearing technique. The teeth were then viewed in a stereomicroscope under 7.5 x magnifications. The canal configurations were characterized using Vertucci's categorization of canal configuration. Although two roots were found in all teeth under study, 65.8% exhibited three root canals, 34.2% had four root canals. The most prevalent canal arrangements found in mesial roots were Vertucci's type (IV) 70.7% and in distal roots Vertucci's type (I) 65.8% respectively.
Key Words: Mandibular first molar, root canal morphology, canal configuration, mandibular first molar morphology.
INTRODUCTION The goal of endodontic treatment is thorough mechanical and chemical debridement of the entire pulp cavity in addition to the attainment of hermetic seal along the entire root canal system.1,2 Therefore it is essential for the clinician to have adequate knowledge of root canal anatomy and morphologic variations in order to reduce the probability of treatment failure.3 It is now well accepted that mandibular first molar exhibits a number of anatomical variations not only in number of roots but also in canal morphology.2,4 Anatomically permanent mandibular first molar typically displays a mesial and a distal root with two mesial and one distal canal. Other studies describe high prevalence of two canals in distal root in different population.5,6,7 Variations in morphology of canals and number of roots appear to have a genetic predisposition in addition to environmental influence.8 Hence a clinician should also be well aware of racially prevalent morphology.
The significant variant in mandibular first permanent molar is the existence of supernumerary root that can be found distolingually. This structure was first discovered by Carabelli then named as Radix Entomolaris, and is generally smaller than the distobuccal and mesial root. Moreover, it may be partially fused with other roots or separated.10 The morphology of mesial root allows intercanal communications and isthmi11 a narrow connection...