DOSIMETRY AND DIAGNOSTIC ACCURACY OF INTRAORAL AND EXTRAORAL BITEWINGS IN DETECTING APPROXIMAL CARIES

Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology

Background

Traditionally, interproximal caries has been diagnosed radiographically by intraoral bitewing radiographs. Although this has been the conventional practice, the challenge of accommodating the film/ image receptor in the mouth, especially in patients with a gag reflex, has affected image acquisition and quality. A new method of acquiring bitewings with an extraoral approach has been recently introduced but the quality and diagnostic efficacy along with the radiation dosage of these techniques have not been well studied.

Objective(s)

The aim of this study was to evaluate the diagnostic accuracy of intraoral and extraoral bitewings (IOBs and EOBs) in their ability to detect proximal caries and to compare the effective doses from both techniques.

Study Design

Human teeth with or without proximal caries were used in this study. Carious lesions were created with different degrees of decalcification on 60 teeth (120 surfaces). These teeth were then placed into sockets of dry human skulls. Intraoral bitewings were acquired using a Kavo LM/CM109 wall-mounted X-ray tube with exposure parameters of 70 KVp, 7 mA, and 0.125 second. Extraoral bitewings were acquired with a Planmeca Promax at 74 kVp,7 mA, and 7.5 seconds. Two radiologists and a general dentist scored the radiographs using standardized software (MiPACS) and display monitors. Dose measurements were done on an anthropometric RANDO phantom. OSLdot dosimeters were used at 24 sites for radiation dose measurements. Fifteen exposures were performed for each dosimeter, and absorbed dose was calculated as an average of the15 exposures using the International Commission on Radiological Protection (ICRP, 2007) tissue weighting factors.

Results

For the diagnosis of interproximal caries, extraoral bitewings showed a sensitivity of 92.3% and specificity of 93.4%, whereas intraoral bitewings showed sensitivity of 94.5% and specificity of 96.8%, Interim dosimetry analysis showed that the doses for IOBs and EOBs were comparable but were slightly different for intraoral membranes.

Discussion/Conclusions

EOBs showed comparable results to IOBs in the detection of approximal caries and had similar effective doses.
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