human 4 mandibular first molar Humans 3 adult 3 cone beam computed tomography 3 female 3 male 3 Adult 2 Article 2 Bicuspid 2 Cone-Beam Computed Tomography 2 Dental Pulp Cavity 2 Female 2 Incisor 2 Male 2 Middle Aged 2 Young Adult 2 anatomy 2 anatomy and histology 2 article 2 comparative study 2 dental pulp cavity 2 incisor 2 major clinical study 2 mandibular second premolar 2 maxillary first premolar 2 middle aged 2 morphology 2 premolar tooth 2 prevalence 2