A comparison of a new dental X-ray film, Agfa Gevaert Dentus M4, with Kodak Ektaspeed and Ultraspeed dental X-ray films.

A new dental X-ray film, Agfa Gevaert Dentus M4, has recently been introduced. Its diagnostic ability for approximal caries and its sensitometric properties were compared with those of Kodak Ultraspeed and Ektaspeed dental X-ray films. Seven general practitioners and six consultants in oral radiology recorded both incipient and manifest approximal caries on radiographs of 100 extracted premolars. ROC-curve technique was used to analyse the results. A significant difference in diagnostic accuracy for both incipient and manifest caries was found between Ektaspeed and Dentus M4, but not between Ektaspeed and Ultraspeed or between Ultraspeed and Dentus M4. Ektaspeed had the highest diagnostic accuracy, 0.79, while Dentus M4 had the lowest, 0.72. No significant differences were found between the different films in their ability to separate sound from cavitated surfaces. The speed and contrast of the three dental X-ray films were measured according to ISO 3665. Dentus M4 film was found to be 1.8 times faster than Ektaspeed and 2.8 times faster than Ultraspeed. Dentus M4 had a lower film contrast than both Ultraspeed and Ektaspeed. Films of the three different types and with about the same expiry date were stored in seven different clinics. One film of each type was developed each month over a 16-month period under standardized conditions. Base plus fog density was measured. The Dentus M4 had a more rapid build up of fog compared to Ultraspeed and Ektaspeed films. We conclude that the new Dentus M4 film has a limited value in the diagnosis of incipient caries.