Comparison of serial films can provide the practitioner with invaluable information, allowing an assessment of the progression or arrest of approximal carious lesions, and of the level of alveolar bone. Meaningful comparisons are difficult however, if different angles and distances in relation to the film, object and focus are used for each exposure; the standardization of these variables by the use of film-holding and beam-aiming devices is therefore advantageous. The evolution of the various designs is reviewed. The development of the separate elements of the devices is considered: film holders, bite blocks, beam-aiming attachments, and additional collimators. These instruments have been used for many applications ranging from routine radiography to clinical research, and differ markedly in their complexity and practicability. The use of film-holding beam-aiming devices provides greater reproducibility in serial examinations, and allows the collection of valuable longitudinal information regarding caries and periodontal disease. In addition, such devices allow a reduction in the dose of radiation received by the patient, an improvement in image quality, and a more efficient technique. Therefore, their use is strongly advocated.