Dental radiograph quality

Key Points

• The taking and processing of panoramic radiographs is associated with many possible faults which affect diagnostic quality.

• In the series of radiographs studied, approximately one in every three was non-diagnostic.

• Careful attention to positioning patients correctly and to ensuring a good standard of processing would lead to a marked reduction in poor quality radiographs.

• However, as type and number of faults vary considerably between dentists, individual analysis of each dentist's quality problems may be more effective than 'blanket' recommendations on quality improvements.

Abstract

Objective

To assess the quality of panoramic radiographs in a sample of general dental practices, to determine the relative frequency of errors and to identify those errors directly responsible for diagnostically inadequate images.

Materials and methods

Examination of 1,813 panoramic radiographs obtained from 41 general dental practitioners and recording of faults. The study was carried out in 1998. Radiographs were judged as being 'excellent', 'diagnostically acceptable' or 'unacceptable'.

Results

Only 0.8% of films were 'excellent', 66.2% were 'diagnostically acceptable' and 33% were 'unacceptable'. The most common faults which directly contributed to failure of the radiographs were antero-posterior positioning errors, low density and low contrast.

Conclusions

The quality of panoramic radiographs was considerably lower than standards recently set for primary dental care. The quality of panoramic radiography could be improved by careful attention to radiographic technique and processing.

Main

The quality of panoramic radiographs in a sample of general dental practices Rushton V. E., Horner K., and Worthington H. V. Br Dent J 1999; 186: 630–633

Comment

All persons involved in the taking of dental radiographs should now be continually assessing the subjective quality of their radiographs, and we should be moving toward a situation where external audit of quality assurance is in place by the year 2001.¹ A clear, practical guide to applying quality ratings to processed radiographs is provided in the NRPB Guidelines which were published in 1994. The need to aim for quality radiography is fundamental as the basis for sound interpretation of radiographic changes due to disease, especially as radiographs may be the gold standard for accurate diagnosis, for example in the use of bitewings for caries assessment. Clearly radiographs which are deemed to be unacceptable are of virtually no value, and merely add to the patient's radiation dose, and ultimately to the overall population dose. The Guidelines give targets of not less than 70% excellent films, not greater than 20% diagnostically acceptable, and not greater than 10% unacceptable.

This article has investigated the quality of panoramic films taken in general dental practice in England and Wales, and demonstrated a worrying level of unacceptable films (33%). One of the concerns highlighted by this paper is raised by the authors who comment in their discussion 'It would seem unlikely that dentists who perceive their own radiographic quality as poor would be eager to expose their deficiencies to others'. There is no indication that the dentists were invited to comment on the quality of the images, as assessed by themselves, and it would be interesting to include this aspect if a similar study is carried out elsewhere.

Continuing education courses and articles in journals can be used to help raise standards, but without an awareness that a deficiency exists, it is likely that those most in need of improvement will fail to take notice. High standards are taught at undergraduate level — at what stage thereafter do they start to decline? We need to find out in order to plan appropriate remedial education.

There is another point that requires to be addressed, and further study is certainly indicated. Are the targets of 'not less than 70%' for excellent films realistic and achievable? Should we consider revisiting these proportions and, whilst there should be no let-up on the not greater than 10% unacceptable as a target, perhaps modify the proportions of diagnostically acceptable and excellent films, as the authors suggest. One approach would be to say that at least 90% of all films should be diagnostically acceptable, with dentists and radiographers aiming to continually improve the proportion of this figure that can be considered to be excellent.