The status of Spain's dental practice following the European Union directive concerning radiological installations: 11 years on (1996-2007).

Objectives: The aim of this study was to assess the influence of European Union legislation on dental radiology practice in Spain and the reduction in doses administered in dental radiological installations 11 years after its introduction.

Methods: A total of 19 079 official reports on dental surgeries from 16 Spanish autonomous regions published between 1996 and 2007 were studied. We analysed the physical characteristics of the X-ray units, anomalies, film processing, exposure times and mean radiation doses administered in clinical situations.

Results: The dose applied to obtain a radiograph of an upper second molar had decreased by 37% up until 2007, the mean dose being 2.7 mGy, with 81.1% of installations using a dose of less than 4 mGy, with a reference dose for the 3(rd) quartile of 3.6 mGy. Of note was the incorporation of digital systems (50.1%), which are gradually replacing manual processing systems (45.3%). There were significant differences between the systems: direct digital radiology < indirect digital radiology = Insight = Ektaspeed = Ultraspeed (P < 0.001). In installations with digital systems, 6.3% used more than 4 mGy (20.5% with direct radiology and 3.2% with indirect radiology) and 7.4% a dose of less than 0.5 mGy, with a mean dose of 1.8 mGy and a reference dose for the 3(rd) quartile of 2.3 mGy.

Conclusion: There has been a gradual improvement in dental radiology practices; however, the incorporation of digital systems has not resulted in all the benefits hoped for, and mistakes are frequent. Besides the physical parameters that have been established, anatomical and clinical image quality criteria should be established to convince dentists of the real benefits of incorporating quality guarantee procedures in their practices.