[The determination of suitable film-screen cassette combinations for orthodontic x-ray technics]

16 film-screen cassette combinations (FSCC) were compared with regard to their detail sharpness and the radiation dose required. After standard adjustment to a uniform average optical density, the contrast and detail were analysed using a self-constructed microdensitometer. The following results were found; on average there is a 14.5% dose reduction using carbon fiber cassettes compared with aluminium cassettes. FSCC with especially low exposure time are: Cronex 2, fast detail, Du Pont (0.4 sec); Cronex 2, NPU, carbon fiber cassettes (0.5 sec); Curix RP1, NPU, carbon fiber cassettes (0.64 sec). The loss of quality associated with this and measured with the microdensitometer is insignificant for clinical orthodontic purposes. This study concludes that differences in contrast and detail do not justify the use of cassette combinations which require a high dose of radiation.