Aim: The aim of this case report is to present clinical and advanced radiographic features of an unusual impacted tooth in the floor of mouth. Case Report: A 37-year-old female patient presented to our department with history of swelling that was localized in right floor of mouth. Clinically it was noticed that her all permanent teeth in the right quadrant were present. So, we first underwent for her occlusal radiography in relation to the offending region where tooth like structure was found lying horizontally with complete presentation of crown and root part. Then, we underwent for an advanced three-dimensional radiographic technique of CBCT, with the purpose of detailed assessment of tooth like structure. After complete assessment patient was advised for the removal of tooth and hence was referred to the Department of Oral Surgery to relieve the pain and the patient was followed up periodically. Discussion: In cases of having a suspicious diagnosis of bony hard lesion in floor of mandible like sialoliths, mandibular tori, impacted tooth : periapical, orthopantomography or occlusal radiographs can be indicated to detect it. But the only drawback with these conventional techniques is that they being the 2-dimensional are not sufficient for determining of the exact localization and the relation with adjacent structures and extent cannot be determined. Thereby, Cone beam computed tomography that is a three-dimensional tool is proven more successful in defining the localization as in our case of retained deciduous impacted teeth. Conclusion: In the diagnostic assessment of such cases cone beam computed tomography has high scope in better outcome results in managing the patients.