Correlation of imaging and clinical features in the assessment of mandibular invasion of oral carcinomas.

The detection in the mandible of early local spreading of adjacent primary malignancies poses a difficult problem. A survey of 60 patients suspected of carcinomatous mandibular infiltration was undertaken, and the most important clinical and imaging data were studied. Tumor localization and bone scintigraphy proved to offer the most important predictive power. A decision tree and a logistic regression model which determines a score function combining these characteristics were designed. This decision tree improves the sensitivity and specificity of the preoperative assessment and provides the surgeon with an algorithm for the accurate estimation of early mandibular invasion.

CT assessment of orbital volume in late post-traumatic enophthalmos.

The potential of CT to facilitate preoperative planning of reconstructive maxillofacial surgery by orbital volume quantification was analysed in 11 patients with traumatic enophthalmos as a late sequela of zygomatic fractures. We carried out biplanar CT examination of the orbits, and calculated total orbital and fat volumes for the healthy and enophthalmic sides. Displacement of the orbital floor and lateral wall was present in 11 and 7 cases respectively. Indentation of the medial wall was noted in 9 cases. Quantitative evaluation of the orbital cavity revealed a significant increase (P < 0.0188) in total volume on the enophthalmic side, the difference between the two sides ranging from 9.2% to 36.4%, mean 17.9%. The degree of enophthalmos, measured radiologically as 2.5-5 mm, correlated with the increase in orbital cavity volume (P = 0.000076). Enophthalmos was 2.5-3 mm in 7 cases (63.6%) and 3.5-5 mm in 4 (36.4%). This corresponded with a mean increase in orbital volume of 3.4 ml (12.3%) and 7.1 ml (27.8%) respectively. Fat atrophy was not an aetiological factor in the production of post-traumatic enophthalmos.

A new method for assessing the temporomandibular joint quantitatively by dental scan.

The objective of this study was to assess the applicability of a multiplanar reformatting program (dental scan) for delineation and quantitative evaluation of the temporomandibular joint (TMJ) in the sagittal and coronal planes using the data of axial computed tomography. The resulting images were compared with standardized linear tomograms and direct sagittal and frontal computed tomography. Standardized linear tomograms and computed tomography of the TMJ in axial, frontal and sagittal planes were obtained in 11 patients. The axial computed tomography slices were then reconstructed in oblique frontal and sagittal planes according to the horizontal condylar angle of the TMJ by dental scan software. For each patient and each of the three imaging methods, 14 measurements were undertaken and 24 qualitative characterizations were assessed. Axial computed tomograms in combination with their corresponding coronal and sagittal reconstructions were more accurate than conventional tomograms. Direct coronal and sagittal scans gave the most detailed images, but required additional radiation dose, time and cost. Reconstructions of axial computed tomography slices of the TMJ using the dental scan software show several advantages over linear tomograms. They allow qualitative as well as quantitative evaluation of the TMJ.

[Mandibular fractures due to implant management--incidence, mechanism of injury and therapeutic characteristics]. / Unterkieferfrakturen infolge Implantatversorgung--Inzidenz, Verletzungsmechanismen und therapeutische Besonderheiten.

We report of 5 of 337 patients (1.48%), in whom a fracture of the edentulous atrophied mandible occurred after dental implants had been inserted. In 79 patients a sandwich osteotomy (anterior and/or lateral mandible) had been carried out together with the insertion of implants. The reason for a fracture was infection in 3 patients and weakening of the atrophied mandible by the additional osteotomies in 2 patients. One of the latter two was seen intraoperatively and fixed immediately using miniplates. The other occurred about 4 weeks postoperatively and was not discovered until callus had been developed. Consequently only 4 of the 5 patients were treated by osteosynthesis. In two patients no implants were lost. The application of bone morphogenetic protein (BMP) helped to avoid the loss of implants because it accelerated ossification of the fracture and the integration of the implants.