Impact of Rectangular Collimation on Quality of Intraoral Radiographs: Findings from a Clinical Audit at a Dental Practice.

Background/

Objectives

Rectangular collimation (RC) reduces patient radiation exposure but is uncommonly used due to cone-cut concerns. An audit at a dental practice was conducted to analyze impact of RC on the quality of intraoral radiographs.

Methods

Four X-ray tubes with RC were used. 360 intraoral X-rays were collected, blinded and scored to pre-set qualitative criteria: maximum 14 points for bitewing radiographs (BWs), and 13 for periapical radiographs (PAs). Quality of the X-rays was assessed.

Results

We found that 48.1% were acceptable, 32.5% were unacceptable and only 19.4% were good X-rays. The loss of image quality was unrelated to RC. Three cone-cuts occurred in PAs without RC. The mean scores for PAs performed without or with RC were as follows: 9.3 ± 1.9 points and 9.6 ± 1.9 points, respectively (p = 0.166). The mean scores for BWs performed without or with RC were as follows: 8.0 ± 1.9 points and 7.1 ± 1.9 points, respectively (p < 0.001). All scores declined over time.

Conclusions

This audit highlighted the need for refresher training on film-holder use and the importance of regular maintenance of dental X-ray equipment. Decline in X-ray quality over time was related to wear and tear of X-ray equipment, incorrect image contrast, and technical errors unrelated to RC. No cone-cuts occurred when using RC.