Advantage of Long Cone Technique: 1. Accuracy: The paralleling technique produces an image that has dimensional accuracy (A profile view of the tooth with buccal and lingual roots projected in their normal respective lengths as buccal and lingual cusps correctly related on the same plane); the image is very representative of the actual tooth. The radiographic image is free of distortion and exhibits maximum details and definition. There is no overlap of related structures (eg. the zygomatic shadow), all shadows of anatomical structures are cast in their proper anatomic position. This accuracy is due to:Increased source film distance. Object and film are parallel to each other. Central ray strikes perpendicular to the long axis of the tooth and film. Though the object film distance is increased, it is compensated by increased source film distance and therefore, there is decreased enlargement. The increased kVp, to reduce exposure time, as the source film distance is increased, helps by reducing secondary and unwanted, short wavelength radiations.2. Simplicity: This technique is simple and easy to learn and use. The film holder with a beam alignment device eliminates the need for all dental surgeons to determine horizontal and vertical angulations and also eliminates chances of dimensional distortion and coning off. 3. Duplication: This technique is easy to standardize and can be accurately duplicated or repeated, when serial radiographs are indicated. As a result, comparison of serial radiographs exposed using this technique have great validity. 4. Facial screens can be used. 5. There is decreased secondary radiation. 6. The radiographs produced give,An excellent bone level assessment. No elongation or foreshortening seen in the periapical region. Interproximal caries is clearly indicated.7. The shadow of the zygomatic bone appears above the apices of the molar teeth. 8. The periodontal bone levels are well represented. 9. The periapical tissues are accurately shown with minimal foreshortening or elongation. 10. The crowns of the teeth are well shown enabling detection of proximal caries. 11. The relative positions of the film packet, teeth and X-ray beam are always maintained, irrespective of the position of the patient’s head. This is useful for handicapped and compromised patients.