Page 143 - Craniomaxillofacial Implant Surgery - Jeroen P.J. Dings

SUMMARY
Chapter 1 of this thesis provides a general introduction on different approaches to reconstruction of CMF defects. The evolution of endosseous implants in the last decennia results in an effective and safe anchorage tool for craniomaxillofacial (CMF) prostheses. The success of osseointegrated CMF implants in effectively anchoring CMF prostheses and, thereby, rehabilitating patients with extensive soft- and hard tissue defects has been widely confirmed in literature. Still, a number of technical and medical topics remain controversial. The general aim of the research described in this thesis was to assess the accuracy of preoperative planning, the subsequent placement, and the clinical outcomes of CMF implants, including the survival rate and patient-reported outcomes. In addition, prosthetic rehabilitation was compared with autologous reconstruction in restoring CMF defects.
Accurate estimation of the available bone dimensions is crucial for preoperative implant planning. Two imaging techniques are commonly used for pre-operative planning of CMF implants: multi-slice computed tomography (MSCT) or multi-detector computed tomography (MDCT) and, more recently, cone-beam computed tomography (CBCT). Unfortunately, literature is scarce on measurement accuracy of bony dimensions at craniofacial locations using CBCT and MDCT. Accuracy of implant treatment planning is dependent on performance differences among these imaging systems with regard to radiation dose, acquisition technique, reconstruction parameters, spatial resolution and perceived image quality. The aim of the study described in Chapter 2 was to determine the accuracy of linear measurements on three-dimensional (3D-) cross- sectional images of different CMF regions obtained with CBCT and MDCT and the possible influence of brightness and contrast settings on the registered accuracy.
In total, five dry human cadaver skulls were used. For orientation, cuts were made with 8 a circular bone saw at the ideal implant positions in the nasal-, orbital- and temporal
regions prior to acquisition of X-Ray data. Subsequently, CBCT and MDCT images
were ordered. Hereafter, clinical measurements with a digital caliper were executed
by three independent observers. After the cross-sectional planes were located on the 3D-rendered reconstructions of the CBCT and MDCT images, linear measurements were carried out on the outer bony dimensions at the level of the bony reference holes. Two standard contrast settings of two different planning software programs were used when performing linear measurements on the radiographic images. Measurement
Summary in English and Dutch
141