Anatomic Variation 1 Dental Pulp Cavity 1 Female 1 Humans 1 Imaging, Three-Dimensional 1 In vitro study 1 Male 1 Maxilla 1 Maxillary first molars Microcomputed tomography (micro-CT) 1 Molar 1 Prevalence 1 Radiography, Dental 1 Root Canal Therapy 1 Root canal orifices 1 Saudi Arabia 1 X-Ray Microtomography 1 adult 1 anatomical variation 1 anatomy and histology 1 article 1 controlled study 1 dental pulp cavity 1 dentist 1 diagnostic imaging 1 endodontic procedure 1 epidemiology 1 female 1 human 1 major clinical study 1