Standardization of a cone beam computed tomography machine in evaluating bone density: a novel approach.

BACKGROUND: Advent of cone beam computed tomography (CBCT) in dentistry has brought us to a new era of precise imaging. Radiographic evaluation of a CBCT image is more informational when compared to CT. The density measurements in CBCT images are based on greyscale values, which are more accurate in CT and these values are inconsistent across various CBCT machines. Hence, we aim at standardizing a single CBCT scanner to evaluate or determine tissue density from the greyscale values. METHODS: A total of 8 halves of undamaged, dry goat mandibles are included in the study. Scans of the bone are obtained using the KODAK CBCT unit and the PHILLIPS CT machine respectively. Densities are evaluated at 96 points on both the CT scans and the CBCT scans, respectively, using the Radiant Dicom viewer. The obtained data is entered into the excel spreadsheet and subjected to statistical analysis. RESULTS: The greyscale values are obtained from each of the CBCT scans. Hounsfield units are calculated from CT images coinciding with the same points on CBCT scans. The collected data is subjected to linear regression analysis and an equation is derived to determine Hounsfield units (calculated HU units) from greyscale values of CBCT images. We found no significant difference between the mean original HU units and the mean calculated HU units, thus making the equation reliable for calculating HU units from CBCT greyscale values. CONCLUSIONS: Our results conclude that the technique was effective in calculating the Original density of tissues using grey standards of CBCT scans.

Acromelia-oligodontia syndrome.

This case report describes a patient with ankyloglossia, oligodontia, unilateral hypoplasia of the zygoma and mandible, along with bilateral distal reduction anomalies of his limbs without long bone abnormalities. This may represent a mild variant of oromandibular limb hypogenesis syndrome, expanding the phenotypic spectrum, or a previously unrecognized malformation syndrome.

Idiosyncratic Presentation of Cemento-Osseous Dysplasia - An in Depth Analysis Using Cone Beam Computed Tomography.

Bone dysplasias comprise of a condition where the normal bone is replaced with fibrous tissue. Periapical Cemento-Osseous Dysplasia (PCOD) is a benign fibro-osseous condition where bone tissue is supplanted with fibrous tissue and cementum-like material. This condition affects mostly mandibular anterior region and rarely occurs in the maxilla. PCOD is seen above 30 years of age and has slight female predilection. Generally the teeth related to such lesions appear to be vital and are usually asymptomatic. These lesions are mostly seen during routine radiographic examination whose presentation may vary from complete radiolucency to dense radiopacity. The advent of Cone Beam Computed Tomography (CBCT) has brought a massive change in the field of dentistry which has become an important tool for diagnosis. Hence we hereby present an unusual case of cemento-osseous dysplasia in an unfamiliar location with an atypical presentation. The shape of the pathology was completely idiosyncratic and different from an orthodox lesion of COD, as the lesion was observed to grow out of the palatal surface with a prominent palatal expansion. This case highlights the importance of CBCT in radiographic diagnosis and in evaluating the characteristics of such lesion, which present with high diagnostic dilemma.