RADIOGRAPHIC INTERPRETATION

Interpretation: Step by step analytical process that provides an exact idea of the clinical problem and helps to achieve the final diagnosis of any particular lesion.

I-Essential requirements for interpretation 1- Optimum viewing conditions 2- Understanding the nature and limitations of the black, white and grey radiographic image. 3- Knowledge of what the radiographs used in dentistry should look like, so a critical assessment of individual film quality can be made. 4-Detailed knowledge of the range of radiographic appearances of normal anatomical structures. 5- Detailed knowledge of the radiographic appearances of the pathological conditions affecting the head and neck. 6- A systematic approach to viewing the entire radiograph and to viewing and describing specific lesions. 7- Access to previous films for comparison.

1- Optimum viewing conditions • An even, uniform, bright light viewing screen (preferably of variable intensity to allow viewing . of films of different densities) .• A quiet, darkened viewing room • The area around the radiograph should be masked by a dark surround so that light passes only through the film. • Use of a magnifying glass to allow fine detail to be seen more clearly on intraoral films. • The radiographs should be dry.

Steps of interpretation Localization. Observation. General consideration. Interpretation. Correlation.

Localization: Localized or generalized. Position in the jaw. Single or multiple. Size.

Observation: All shadows, other than the localized shadows of the normal landmarks must be observed. For example: shadows in crowns, cervical area, roots, restorations, size of root canals, periodontal membrane space, periapical area, alveolar crest, foreign bodies, integrity of bone.

General consideration: A radiograph shows only 2 dimensions of a 3 dimensional object (width and height but not the depth) Cervical burnout: usually appears as cervical Radiolucency and misinterpreted by caries; this occurs due to less density and more penetration of rays. Pulp exposure: never to be determined from radiograph but only the proximity to the pulp.

Interpretation: Teeth Studying the features of teeth and bone: Study the whole tooth,(crown, root, enamel, pulp), number of teeth and finally supporting structures, (Periodontal membrane space, lamina dura , alveolar crest).

Bone: Changes in bone may include: 1- Changes in density. 2- Changes in the margin. 3- Changes inside the lesion. 4- Effect on surrounding tissues. 5- Changes in structure.

Correlation: The final step is to correlate all of the radiographic features to reach a radiographic differential diagnosis. Then to draw a final diagnosis, we have to correlate other data as case history, clinical examination, and other diagnostic aids with the radiographic differential diagnosis

Image analysis Identify normal anatomic landmarks. Knowledge of normal v/s abnormal. Attention to all regions on the film systematically. Three visual circuits.

First visual circuit: intraoral images Periapical before bitewing images Right maxilla to left; left mandible to right One anatomic structure at a time:Ex: posterior maxilla-maxillary sinus,tuberosity,zygomatic process Normal anatomy: Ex: bones, canals, foramina. Check for symmetry.

Use a systematic process Go back to the first quadrant and look at the trabecular pattern. Is it: Normal Symmetrical when compared to the contralateral side Sparse Dense In the direction of anatomical stress Altered

Second visual circuit Examination of bone: Height of alveolar bone Crest relative to teeth Loss of height-more than 1.5 mm-periodontal disease Lamina dura + PDL space + tooth roots Carcinoma-erosion of alveolar crest+ ill defined borders.

Third visual circuit Examination of dentition & associated structures Number, Sequence, appearance, root structure Crowns –defective enamel, caries Intreproximal areas & restorations Pulp chambers-size, content Bone-radioluscent/radioopaque lesions