Background and Objective: Periapical radiography is extensively utilized in dental practice, resulting in considerable radiation exposure to the eyes. However, relevant studies remain limited. This study aims to compare the absorbed dose to the eye lens between the bisecting-angle and paralleling techniques in maxillary periapical radiography.
Methods: In this cross-sectional study, a total of 32 periapical radiographs were acquired from the maxilla—16 utilizing the paralleling technique (PA-Tech) and 16 using the bisecting-angle technique (BI-Tech). Radiographic exposures were performed on right and left sides across four regions: central and lateral incisors, canine, premolars, and molars. To measure the radiation dose delivered to the eye, thermoluminescent dosimeters (TLDs) were placed at the eye lens level of two dental phantoms. After the radiographic procedures, the TLDs were carefully read, and the measured dose values were statistically compared between the two techniques.
Findings: The mean absorbed dose to the eye lens on the irradiated side was greater for the paralleling technique (0.560±0.324 mGy) than for the bisecting-angle technique (0.434±0.386 mGy). On the non-irradiated side, a similar pattern was observed, with the paralleling technique yielding a higher mean dose (0.038±0.022 mGy) compared to the bisecting-angle technique (0.031±0.011 mGy). Nevertheless, these differences did not reach statistical significance on either side. When comparing exposed versus non-exposed sides in each technique, the absorbed dose to the eye lens was found to be significantly greater on the exposed side for both techniques (p<0.001).
Conclusion: The present findings suggest that the bisecting-angle technique may be preferred over the paralleling technique for periapical radiography of the central incisor and canine regions, as it is associated with a lower radiation dose to the patient's eyes.