Multiple idiopathic cervical root resorption was found most frequently associated with younger females. This condition appeared to be of unknown aetiology and uncertain natural history.

The effective dose from computed tomography of the maxillofacial complex has been estimated and used for an assessment of risk. For each scan sequence 64 TLDs were placed in 27 selected sites in the upper portion of a tissue-equivalent human phantom to record the equivalent dose in radiosensitive organs/tissues. Equivalent doses ranged from 0.11 mSv (bone marrow, maxillary scan) to 20 mSv (salivary glands, mandibular scan). By the use of a calculation that included the salivary glands as part of the remainder, two contiguous 1 cm axial slices of the maxilla were found to result in an effective dose of 0.1 mSv, and four contiguous 1 cm axial slices of the mandible in an effective dose of 0.76 mSv. Effective doses of this magnitude represent a probability of stochastic effects of the order of 8 X 10(-6) and 56 X 10(-6) respectively.

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There are no data relating complex film tomography with effective dose that may be used to estimate the relative risk associated with dental implant diagnostics. The purpose of this study was to calculate the effective dose and estimate risk from the use of the Scanora multimodal imaging system. With the use of a tissue equivalent human phantom and thermoluminescent dosimetry, panoramic radiography was found to result in an effective dose of 26 microSv, while complex film tomography resulted in an effective dose of< 1 microSv to 30 microSv depending on the anatomical location of the imaging plane and the collimation option. An effective dose of this magnitude for panoramic radiography was estimated to represent a probability for stochastic effects on the order of 1.9 x 10(-6). Similarly, the effective dose associated with film tomography may be estimated to be equal to a probability for stochastic effects in the range of << 1 x 10(-6) to 2.2 x 10(-6).