Dan C. Colosi

Significant reduction in dental cone beam computed tomography (CBCT) eye dose through the use of leaded glasses.

OBJECTIVE In light of the increased recognition of the potential for lens opacification after low-dose radiation exposures, we investigated the effect of leaded eyeglasses worn during dental cone-beam computerized tomography (CBCT) procedures on the radiation absorbed dose to the eye and suggest simple methods to reduce risk of radiation cataract development. STUDY DESIGN Dose measurements were conducted with the use of 3 anthropomorphic phantoms: male (Alderson radiation therapy phantom), female (CIRS), and juvenile male (CIRS). All exposures were performed on the same dental CBCT machine (Imtec, Ardmore, OK) using 2 different scanning techniques but with identical machine parameters (120 kVp, 3.8 mA, 7.8 s). Scans were performed with and without leaded glasses and repeated 3 times. All measurements were recorded using calibrated thermoluminescent dosimeters and optical luminescent dosimetry. RESULTS Leaded glasses worn by adult and pediatric patients during CBCT scans may reduce radiation dose to the lens of the eye by as much as 67% (from 0.135 ± 0.004 mGy to 0.044 ± 0.002 mGy in pediatric patients). CONCLUSIONS Leaded glasses do not appear to have a deleterious effect on the image quality in the area of clinical significance for dental imaging.

Generation of Intra-oral-like Images from Cone Beam Computed Tomography Volumes for Dental Forensic Image Comparison†

Identification of unknown individuals using dental comparison is well established in the forensic setting. The identification technique can be time and resource consuming if many individuals need to be identified at once. Medical CT (MDCT) for dental profiling has had limited success, mostly due to artifact from metal‐containing dental restorations and implants. Description: The authors describe a CBCT reformatting technique that creates images, which closely approximate conventional dental images. Method: Using a i‐CAT Platinum CBCT unit and standard issue i‐CAT Vision software, a protocol is developed to reproducibly and reliably reformat CBCT volumes. The reformatted images are presented with conventional digital images from the same anatomic area for comparison. Conclusion: The authors conclude that images derived from CBCT volumes following this protocol are similar enough to conventional dental radiographs to allow for dental forensic comparison/identification and that CBCT offers a superior option over MDCT for this purpose.

Optimising radiographic bitewing examination to adult and juvenile patients through the use of anthropomorphic phantoms.

Four anthropomorphic phantoms (an adult male, an adult female, a 10-y-old child and a 5-y-old child) were exposed to bitewing radiographs at film and digital settings using both rectangular and round collimation. Optically stimulated dosemeters were used. For children, average organ doses were <40 µGy and the organs with the highest doses were the salivary glands, parotid, oral mucosa, skin and extrathoracic airway. For adults, average organ doses were <200 µGy. Highest adult doses were to the salivary glands, oral mucosa and skin. Effective doses ranged from 1.5 to 1.8 µSv for children and from 2.6 to 3.6 µSv for adults when optimised technique factors were employed, including digital receptors, rectangular collimation, size-appropriate exposure times and proper clinical judgment. Optimised doses were a fraction of the natural daily background exposure. Therefore, predictions of hypothetical cancer incidence or detriment in patient populations exposed to such low doses are highly speculative and should be discouraged.

Pilot study: digital subtraction radiography as a tool to assess alveolar bone changes in periodontitis patients under treatment with subantimicrobial doses of doxycycline.

BACKGROUND Subtle changes in marginal alveolar bone level can be demonstrated using digital subtraction of sequential radiographs. OBJECTIVE We aimed to evaluate the practical application of geometrically corrected digital subtraction in a clinical study of alveolar bone response to a drug previously shown to inhibit alveolar bone loss. STUDY DESIGN Selected periapical radiographs were acquired with projective standardization of patients with clinical marginal alveolar bone loss. Subsequently, patients received a 6-month regimen of subantimicrobial doxycycline or placebo. Standardized radiographs of the same alveolar regions were acquired after 3 and 6 months, and baseline radiographs were subtracted from these images. RESULTS Blinded digital subtraction analysis indicated various levels of marginal bone gain in 3 of the 6 patients in the experimental group, whereas in 3 of the 5 placebo patients the method showed bone loss. CONCLUSION These results suggest that geometrically corrected digital subtraction possibly agrees with clinical predictors of bone loss severity.