RESUMEN
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