Radiation dose in dental radiology.

The aim of this study was to compare radiation exposure in panoramic radiography (PR), dental CT, and digital volume tomography (DVT). An anthropomorphic Alderson-Rando phantom and two anatomical head phantoms with thermoluminescent dosimeters fixed at appropriate locations were exposed as in a dental examination. In PR and DVT, standard parameters were used while variables in CT included mA, pitch, and rotation time. Image noise was assessed in dental CT and DVT. Radiation doses to the skin and internal organs within the primary beam and resulting from scatter radiation were measured and expressed as maximum doses in mGy. For PR, DVT, and CT, these maximum doses were 0.65, 4.2, and 23 mGy. In dose-reduced CT protocols, radiation doses ranged from 10.9 to 6.1 mGy. Effective doses calculated on this basis showed values below 0.1 mSv for PR, DVT, and dose-reduced CT. Image noise was similar in DVT and low-dose CT. As radiation exposure and image noise of DVT is similar to low-dose CT, this imaging technique cannot be recommended as a general alternative to replace PR in dental radiology.

Increase in gingival inflammation under academic stress.

Several correlational questionnaire studies have observed a positive relationship between psychological stress and periodontal diseases. This paper analyses the effects of academic stress on periodontal health in a prospective quasi-experimental design. 26 medical students participating in a major exam and the same number of medical students not participating in any exam throughout the study period volunteered for the study. Bleeding on probing was assessed 4 weeks prior to the exam period (baseline) and at the last day of the exam. Severe deterioration in gingival health from baseline to the last exam day were observed more frequently in exam students than in controls (p=0.014). 6 exam students but only 1 control person developed a severe gingivitis at at least one formerly healthy tooth throughout the study period. These results further support the hypothesis that psychological stress is a significant risk factor for periodontal inflammation. Future studies should examine factors mediating this relationship.