Virtual restoration of anatomic jaw relationship to obtain a precise 3D model for total joint prosthesis construction for treatment of TMJ ankylosis with open bite

Temporomandibular joint (TMJ) reconstruction with a TMJ Concepts total joint prosthesis (TMJ Concepts, Ventura, USA) requires a precise 3D model of the jaws in centric occlusion. The authors present a virtual procedure for repositioning the lower jaw in centric occlusion to obtain a precise stereolithographic model for TMJ reconstruction using a custom-made total joint prosthesis in a case of TMJ ankylosis and anterior open bite

Computer Assisted Oral and Maxillofacial Reconstruction

Ablative tumor surgery, orbital and mid face reconstruction as much as skull base surgery requires detailed planning using CT or MRI. Reconstruction is depending on reliable information to choose correct type of grafts and to predict the outcome. This study evaluates the benefit and the indications of computer assisted surgery in the treatment of cranio-maxillofacial surgery.Based on a CT or MRI data set an optical navigation system was used for preoperative planning, intraoperative navigation and postoperative control. Surgery was preoperatively planned and intraoperatively navigated. Preoperatively required soft and hard tissue was measured using the mirrored data set of the unaffected side; size and location of the graft were chosen virtually. Intraoperatively contours of transplanted tissues were navigated to the preoperatively simulated reconstructive result.Computer assisted treatment was successfully completed in all cases (n=107). Preoperatively outlined safety margins could be exactly controlled during tumor resection. Reconstruction was designed and performed precisely as virtually planned. Image guided treatment improves preoperative planning by visualization of the individual anatomy, intended reconstructive outcome and by objectivation the effect of adjuvant therapy. Intraoperative navigation makes tumor and reconstructive surgery more reliable by showing the safety margins, saving vital structures and leading reconstruction to preplanned objectives

The university münster model surgery system for orthognathic surgery. Part II – KD-MMS

<p>Abstract</p> <p>Background</p> <p>Model surgery is an integral part of the planning procedure in orthognathic surgery. Most concepts comprise cutting the dental cast off its socket. The standardized spacer plates of the KD-MMS provide for a non-destructive, reversible and reproducible means of maxillary and/or mandibular plaster cast separation.</p> <p>Methods</p> <p>In the course of development of the system various articulator types were evaluated with regard to their capability to provide a means of realizing the concepts comprised of the KD-MMS. Special attention was dedicated to the ability to perform three-dimensional displacements without cutting of plaster casts. Various utilities were developed to facilitate maxillary displacement in accordance to the planning. Objectives of this development comprised the ability to implement the values established in the course of two-dimensional ceph planning.</p> <p>Results</p> <p>The system - KD-MMS comprises a set of hardware components as well as a defined procedure. Essential hardware components are red spacer and blue mounting plates. The blue mounting plates replace the standard yellow SAM mounting elements. The red spacers provide for a defined leeway of 8 mm for three-dimensional movements. The non-destructive approach of the KD-MMS makes it possible to conduct different model surgeries with the same plaster casts as well as to restore the initial, pre-surgical situation at any time. Thereby, surgical protocol generation and gnathologic splint construction are facilitated.</p> <p>Conclusions</p> <p>The KD-MMS hardware components in conjunction with the defined procedures are capable of increasing efficiency and accuracy of model surgery and splint construction. In cases where different surgical approaches need to be evaluated in the course of model surgery, a significant reduction of chair time may be achieved.</p