Effect of using laser guided indicator on the reduction of technical errors in periapical radiographies prepared by dental students

Successful radiography requires a true imagination of central ray. Some technical errors however happen as a result of maladjustment of central ray. Many dental students who begin to learn radiography do not have a comprehensive imagination of the central ray. Using a laser guided indicator for central ray in such cases may serve as a useful training means for better adjustment of central ray. This in vitro study was carried out at the Department of Radiology, Dental School of Isfahan University of Medical Sciences. A total of eighteen students were divided into two groups of nine. In the first group the periapical technique was taught without laser guided indicator while in the second group laser guided indicator was applied in training the students. All students took X-rays from the phantom. Laser guided indicator is made of two low power red laser diodes and is capable of making two perpendicular rays forming a cross (+) in the center of tube which indicates central ray. Totally 216 X-rays were taken and technical errors and the quality of X-rays were evaluated. The results were analyzed statistically via Mann-Whitney and chi Square tests (α = 0.05). The X-rays taken by students showed significant differences in Cone Cutting (p value = 0.014), Overlapping (p value = 0.018) and Elongation (p value < 0.001) between the two study groups. In the subjective review of X-ray quality, the difference was also significant (p value < 0.001). The use of laser guided indicator as a training aid seems to be practical for easier learning of central ray adjustment and reduction of technical errors in taking X-rays by dental students.