Panoramic images are most useful clinically for diagnostic problems requiring broad coverage of the jaw. Common examples include evaluation  of trauma including jaw fractures, location of third molars, extensive dental or osseous disease, known or suspected large lesions, tooth development and eruption (especially in the mixed dentition), retained teeth or root tips (in edentulous patients),  temporomandibular joint  (TMJ)  pain,  and developmental anomalies. Panoramic imaging is often used as the initial evaluation image that can provide the required insight or assist in determining the need for other projections. Panoramic images are also useful for patients who do not tolerate intraoral procedures well. The main disadvantage of panoramic radiology is that the image does not display the fine anatomic detail available on intraoral periapical radiographs. Thus, it is not as useful as periapical radiography for detecting small carious lesions, the fine structure of the marginal periodontium, or periapical disease. The proximal surfaces of premolars also typically overlap. The availability of a panoramic radiograph for an adult patient often does not preclude the need for intraoral films for the diagnosis of most commonly encountered dental diseases. When a full-mouth series of radiographs is available for a patient requiring only general dental care, typically little or no additional useful information is gained from a simultaneous panoramic examination. Other problems associated with panoramic radiography include unequal magnification and geometric distortion across the image. Occasionally, the presence of overlapping structures, such as the cervical spine, can hide odontogenic lesions, particularly in the incisor regions. Clinically, important objects may be situated outside the focal trough and may appear distorted or not be seen at all.   Reference: White and Pharoah's Oral Radiology Principles and Interpretation 7th edition page no 166