This is a clinical audit to assess the quality of bitewing radiographs taken during dental examinations at Farm Street Dental Practice.
Radiography is a useful tool in aiding in diagnosis of dental diseases. Bitewings are mainly taken for caries diagnosis and also can be used to identify alveolar bone levels. At Farm Street, digital radiography is used to reduce radiation dose to the patients. Furthermore as many patients are of high caries risk, bitewings are taken regularly at the practice. I wanted to analyse the image quality of radiographs as I felt it was an important topic to regularly audit and ensure that radiographs are not repeated and radiation dose to the patient is kept as low as possible. This is in accordance with the European guidelines on radiation protection that the radiation dose to the patient should be as low as reasonably practicable (the ALARP principle).
Guidelines by the National Radiological Board have been produced to help practitioners apply the ALARP principle. Methods of dose reduction include factors related to the X-ray equipment such as filtration, collimation, image receptor, voltage, method of X-ray generation. Also there are patient factors such as patient preparation, and careful positioning and beam aligning devices. Quality assurance programmes and use of selection criteria for different radiographs further ensure the radiation dose is kept to the minimum.
Aims
The aims of the audit were:
- Determine the number of radiographs matched to the set criteria
- Determine the cause of poor radiographs
Data collection
Twenty-five patient records were chosen at random and 50 bitewing radiographs were sampled. The National Radiological Protection Board for quality assurance purposes have a three point image quality scoring system which was used to rate all the radiographs (table 1).
Each radiograph was scored a number one to three in five categories – angulation, contrast, focus, exposure and processing. If any radiograph scored a three in any category, it was given an overall score of three rendering it diagnostically unacceptable. Other radiographs were given an overall average score based on the points from all five categories.
The data were further analysed according to the FGDP guidelines for the radiographic standard (shown in table 2).
- Not less than 70 per cent scoring 1.
- Not more than 20 per cent scoring 2.
- Not more than 10 per cent scoring 3.
The radiographs selected were from patients from August 15, 2012 to September 15, 2012. Patients were chosen at random from all four dentists working at Farm Street Dental Practice.
Analysis
The angulation of the radiographs was less than 70 per cent grade 1 and more than 20 per cent grade 2. This was also the case for focus of the radiographs. Figure 1 shows that overall percentage scores of grades 1-3: Overall, the results satisfy the FGDP standards apart from grade 2 which is marginally over 20 per cent.
Recommendations
To ensure improvements in angulation and focus quality of radiographic films, the problems were identified. First of all some dentists in the practice were not using film holders when taking bitewings and therefore problems in angulation were encountered. The paralleling technique is needed to achieve optimum geometry to prevent overlapping contact points and possible obscuring of carious lesions. With the radiographic film parallel to the teeth and holder and careful aligning of the X-ray beam 90 degrees to the film and holder will ensure no correct angulation and a sharp focus on the film. The local rules on how to operate in the local area including advice on paralleling technique were reinforced to all staff so that they could refer to it while taking the X-ray.
Furthermore staff training and quality assurance checks should be carried out to ensure that all things like correct exposure settings are checked. Also, all staff are to emphasise to patients hold still while taking the X-ray. Also if the patient has gagging problems, deep breathing should be advised to these patients. A re-audit is needed to ensure that these changes have resulted in an improvement in the quality rating of films.
Second audit cycle
Fifty bitewings were taken from patient examinations between two weeks from December 2012 till January 2013. The results are shown in table 3.
There was an improvement from the first audit cycle as the grades of the radiographs in all sections and overall exceeded the FGDP guidelines.
Conclusion
Overall, the radiographic film quality rating at Farm Street Dental Practice was good even in the first audit cycle. The main areas for improvement were better focusing and angulation of radiographs which significantly improved once every dentist was using the paralleling technique with the use of film holders. In the future I hope to do another audit on this subject as quality rating of radiographic films is a vital topic in dentistry to ensure optimum quality assurance. This is to ensure correct diagnosis and low radiation dose to the patient.
References available on request.
1 Excellent No erros
2 Diagnostically acceptable Some errors, but nothing which detracts from the diagnostic
utility of the radiograph
3 Unacceptable Errors wich render the radiograph diagnostically unusable
Table 1.
Excellent Diagnostically Acceptable Unacceptable
Angulation 32 14 4
Contrast 41 9 0
Focus 30 20 0
Exposure 45 5 0
Processing 47 3 0
FGDP standard 70% 20% 10%
Table 2.
Excellent Diagnostically Acceptable Unacceptable
Angulation 45 4 1
Contrast 46 4 0
Focus 43 6 1
Exposure 45 5 0
Processing 44 6 0
FGDP standard 70% 20% 10%
Table 3.
Figure 1.
Figure 2.