Assessment for the placement of dental implant is done by-

Cone Beam Computed Tomography (CBCT) is the current gold-standard imaging modality for pre-implant assessment because it provides accurate, three-dimensional evaluation of alveolar bone height, width, density, and the precise location of vital anatomical structures (inferior alveolar canal, maxillary sinus floor, mental foramen), all with a lower radiation dose than conventional medical CT. A two-dimensional OPG (panoramic radiograph) is useful for initial screening but cannot provide the buccolingual/cross-sectional bone width information essential for accurate implant planning, and MRI is not routinely used for bone assessment in implant planning.

Reference: Misch CE. Contemporary Implant Dentistry, 3rd ed. – Diagnostic Imaging for Dental Implants.