Introduction: Dento-alveolar trauma to the maxillary incisors 
often requires combined clinical and radiographical follow-up. 
The number of radiographs can add up substantially in particular 
cases, which subsequently results in a higher patient’s absorbed 
radiation dose. As a consequence from the X-ray beam’s downward 
angulation, the thyroid gland potentially receives a substantial 
amount of radiation, both from the primary beam as from the 
scattered radiation. 
Aim: Assess the absorbed radiation dose by the patient’s 
thyroid gland by means of Personal Computer X-ray Monte Carlo 
calculations (PCXMC® 2.0 software), taking into account voltage, 
milli-Ampères, exposure time, vertical projection angle, beam 
collimation and age of the patient. 
Results: The use of a longer focus-to-skin distance and a 
rectangular collimator resulted in a significant lower radiation dose 
to the thyroid gland. The latter was irrespective of the patient’s age. 
The dose to the thyroid gland was significantly higher in younger 
subjects. The impact of the vertical projection angle was not similar 
for all age categories Conclusion: The dose to the thyroid gland seems to be mostly 
affected by the size of radiated surface, the focus-to-skin distance 
and the milli-Ampère exposure time product. The study assessed 
only the absorbed radiation dose by the thyroid gland under different 
radiographic exposures, mimicking real clinical circumstances and 
did not did not assess image quality. Therefore the results should be 
interpreted with care. 
Keywords: Dento-alveolar trauma; Radiographs; PCXMC®; 
Children; Thyroid glands radiation.