Pre-surgical implant planning at first maxillary molar region using conventional tomography, reformatted cross-sectional, true coronal, and modified coronal spiral computed tomography

Accurate estimation of bone height and width of the intended implant site is highly important to obtain reference measurements that can he used during surgery. It determines the depth and width necessary for surgical drilling, and also the bone height that has to be surgically reduced until a level is reached where the hone width is sufficient for implant placement. Fifteen patients undergoing pre- implant radiographic assessment of maxillary first molar ridge area in relation to the floor of the maxillary antrum. They were being the subject of this study, Conventional cross-sectional tomography; reformatted cross-sectional spiral CT scanning: modified coronal CT images and true coronal CT images were being peformed to all patients. No statistical significant difference was observed between the 4 studied modalities in both bone height and width except there was statistical significant difference between true coronal CT bone width measurements and the other three imaging modalities

Intra- and inter-observers agreement in tracing of submentovertex as a prerequisite for corrected lateral tomography of TMJ

TMJ is a complex articulation that shows great variability from one individual to another and also within each individual, indicating that the normal range of the condyle morphology. angulation, and position are fairly large. Tomography is a better tool for condyle/fossa relationship assessment, the technique overcome the problem of superimposition of anatomic structures hindered, allow accurate and repeatable visualization of TMJ pathology. Before started corrected lateral tomographic examination of the TMJ, submento-vertex cephalometric projection had been taken for determination of the horizontal condylar axis using hypocycloidal multi slice tomography with Comm CAT multidirectional tomograpltic machine. Twenty patients of both sexes with different ages were selected, Measurements of the horizontal condylar angle and the condylar head length were taken from each scanned SMV image, 3 times with one month interval by the same observer, during each tracing; data from the previous scan were obscured. Then tracings of the SMV images were done by 4 observers independently. There was a significant difference in the linear measurements of the condyle head in some of intra-observer and inter-observers measurements in both right and left condyles. Also there was a significant difference in the horizontal condylar angle in intra-observer measurements 7° on the right condylar angle and 8° on the left condylar angle as well as in the inter-observer measurements 8° on the right side and 10° on left side. In addition, there was no significant difference and strong confidence correlation in-between intra-observer and inter-observer measurements except only one of the inter-observer showed a significant difference, also a great reliability and small angle variation in intra-observers measurements compared to inter-observers measurements. Moreover there were some similarities between the intra-observer and inter- observers data, including poor reliability of the condylar poles and poor reliability of the horizontal condylar angles