Franco Persiani

CAD/CAM guided secondary mandibular reconstruction of a discontinuity defect after ablative cancer surgery

A surgical guide is projected to aid the repositioning of the mandibular segments in their original locations, and a reconstruction bone plate is provided to support the fibula free flap. Computer-aided mandibular reconstruction involves three steps: virtual surgical planning, CAD/CAM and rapid-prototyping procedures for the design and manufacture of the customised surgical device and surgery. The duration of the reconstructive phase (<1.5 h intraoperative time) was reduced in comparison with traditional secondary mandibular reconstruction. The bone plate permitted the maximal restoration of the original facial and mandibular contours and the more precise positioning of the residual mandibular ramus in comparison with conventional procedures. No complication was noted during the mean follow-up period of 12 months. The protocol presented in this paper offers some benefits: 1) The virtual environment permitted ideal preoperative planning of mandibular segment repositioning in secondary reconstruction; 2) Intraoperative time was not consumed by approximate and repeated bone plate modelling; 3) Using CT data obtained before primary surgery, the reconstruction bone plate was designed using the original external cortical bone as a template to reproduce the ideal mandibular contour; 4) Prototyped resin models of the bone defect allowed the surgeon to train preoperatively by simulating the surgery.

A CAD/CAM-prototyped anatomical condylar prosthesis connected to a custom-made bone plate to support a fibula free flap

This paper describes a new protocol for mandibular reconstruction. Computer-aided design/computer-aided manufacturing (CAD/CAM) technology was used to manufacture custom-made cutting guides for tumor ablation and reconstructive plates to support fibula free flaps. CT scan data from a patient with an odontogenic keratocyst on the left mandibular ramus were elaborated to produce a virtual surgical plan of mandibular osteotomy in safe tissue for complete ramus resection. The CAD/CAM procedure was used to construct a customized surgical device composed of a cutting guide and a titanium reconstructive bone plate. The cutting guide allowed the surgeon to precisely transfer the virtual planned osteotomy into the surgical environment. The bone plate, including a custom-made anatomical condylar prosthesis, was designed using the outer surface of the healthy side of the mandible to obtain an ideal contour and avoid the bone deformities present on the side affected by the tumor. Operation time was reduced in the demolition and reconstruction phases. Functional and aesthetic outcomes allowed patients to immediately recover their usual appearance and functionality. This new protocol for mandibular reconstruction using CAD/CAM to construct custom-made guides and plates may represent a viable way to reproduce the patient’s anatomical contour, give the surgeon better procedural control, and reduce operation time.

CICLoPE—a response to the need for high Reynolds number experiments

The invention is directed to a process for the preparation of a catalyst component for the polymerization of an olefin by:a) contacting metallic magnesium with an organic halide RX, where R is an organic group containing up to 20 carbon atoms and X is a halide, whereupon the dissolved reaction product I is separated from the solid residual products and whereafter,b) an alkoxy group or aryloxy group containing silane compound is added to the obtained reaction product I, whereupon the precipitate formed is purified to obtain reaction product II,c) which reaction product II is subsequently contacted with TiCl4 and the resulting product is purified to obtain the catalyst component.The invention is characterized in that in step b) the silane compound and reaction product I are introduced simultaneously to a mixing device.

3D restitution, restoration and prototyping of a medieval damaged skull

Purpose – The purpose of this paper is to describe the method of virtually and physically reconstructing the missing part of a badly damaged medieval skull by means of reverse engineering, computer‐aided design (CAD) and rapid prototyping (RP) techniques.Design/methodology/approach – Laser scanning data were used to create the 3D model of the damaged skull. Starting from this digital model, a virtual reconstruction of the missing part of the skull, based on the ideal symmetry with respect to the mid‐sagittal plane, was achieved in a CAD environment. Finally, the custom‐designed model was directly fabricated by means of the RP process.Findings – The result shows that the designed missing part of the skull fits very well with the existing skeletal remains. The final physical assembly of the prototyped element on the damaged skull was tested, restoring it to its whole original shape.Research limitations/implications – The entire process was time‐consuming and may be applied just to the most representative sk...

Computer-aided design and manufacturing construction of a surgical template for craniofacial implant positioning to support a definitive nasal prosthesis.

AIM To design a surgical template to guide the insertion of craniofacial implants for nasal prosthesis retention. MATERIALS AND METHODS The planning of the implant position was obtained using software for virtual surgery; the positions were transferred to a free-form computer-aided design modeling software and used to design the surgical guides. A rapid prototyping system was used to 3D-print a three-part template: a helmet to support the others, a starting guide to mark the skin before flap elevation, and a surgical guide for bone drilling. An accuracy evaluation between the planned and the placed final position of each implant was carried out by measuring the inclination of the axis of the implant (angular deviation) and the position of the apex of the implant (deviation at apex). RESULTS The implant in the glabella differed in angulation by 7.78°, while the two implants in the premaxilla differed by 1.86 and 4.55°, respectively. The deviation values at the apex of the implants with respect to the planned position were 1.17 mm for the implant in the glabella and 2.81 and 3.39 mm, respectively, for those implanted in the maxilla. CONCLUSIONS The protocol presented in this article may represent a viable way to position craniofacial implants for supporting nasal prostheses.

Improving the spatial orientation of human teeth using a virtual 3D approach

Since teeth are resistant to decomposition processes, they provide important and at times unique sources of information about fossil humans. Fortunately, dental remains reflect significant evolutionary changes. These changes make a very important and often exclusive contribution to the definition of new taxa or the attribution of fossil specimens to existing taxa. The traditional approach to dental morphometric analyses usually focuses on the recording of several measures of the tooth with calipers, especially the two basic crown diameters (buccolingual and mesiodistal). However, since these measures do not adequately represent the complex morphology of the tooth, 2D images and 3D digital models of dental morphology have been used. For both types of analysis, the possibility of correctly comparing homologous teeth depends on the adoption of a common orientation system. The lack of such a system makes it difficult to compare the results of different studies. Here we describe a new method for orienting teeth specifically devised for the upper and lower first molar (M1). Samples of unworn maxillary (n=15) and mandibular (n=15) first molars of modern humans were scanned with a Roland Picza 3D digitizer. The 3D virtual models were used to compare our new orientation method with those proposed in the literature. The new orientation system, which meets a geometric criterion, is based on three points identified on the cervical line and ensures acceptable repeatability of the spatial positioning and orientation independent of the shape and wear of the first molar under investigation. This orientation system is a first step toward the creation of a virtual set of hominid and fossil human first molars, which will allow us to make comparisons via a sophisticated and noninvasive approach. This pilot study also provides guidelines to extend the new methodology to the other types of teeth.

New protocol for construction of eyeglasses-supported provisional nasal prosthesis using CAD/CAM techniques.

A new protocol for making an immediate provisional eyeglasses-supported nasal prosthesis is presented that uses laser scanning, computer-aided design/computer-aided manufacturing procedures, and rapid prototyping techniques, reducing time and costs while increasing the quality of the final product. With this protocol, the eyeglasses were digitized, and the relative position of the nasal prosthesis was planned and evaluated in a virtual environment without any try-in appointment. This innovative method saves time, reduces costs, and restores the patients aesthetic appearance after a disfiguration caused by ablation of the nasal pyramid better than conventional restoration methods. Moreover, the digital model of the designed nasal epithesis can be used to develop a definitive prosthesis anchored to osseointegrated craniofacial implants.

A first implementation of an advanced 3d interface to control and supervise uav (uninhabited aerial vehicles) missions

Recent analyses on the uninhabited aerial vehicle (UAV) accidents revealed that several kinds of human-system control problems occur in current UAV missions. Therefore, a design of the manmachine interface that allows for an efficient and effective interaction between the operator and the remote vehicle becomes one of the challenges in the development of more reliable UAVs. This paper presents a first implementation of an advanced interface for UAV ground control station based on a touch screen, a 3D virtual display, and an audio feedback message generator. The touch screen is used to send high level commands to the vehicle, the 3D virtual display provides a stereoscopic and augmented visualization of the complex scenario in which the vehicle operates, and the audio feedback message generator informs the operator about any change in operational scenario. The hardware/software architecture of the interface also includes a planning algorithm and a generic vehicle model. The interface has been tested by simulating several UAV missions. The results have shown that the interface requires an adequate level of workload to command the vehicle and allows the operator to build a good level of awareness of the state of the vehicle under his or her control, as well as of the environment in which it operates.

Design and Manufacturing of Ear Prosthesis by Means of Rapid Prototyping Technology

In this paper, the complete procedure to design and construct reusable moulds for implant-based ear prosthesis and manufacture substructures by means of a computer aided design—computer aided manufacturing (CAD—CAM) procedure and rapid prototyping (RP) technology is presented. The scan of the healthy ear, the virtual superimposition of its mirrored image on to the defective side, and the rapid manufacturing of the substructure and of the mould eliminate several steps of traditional procedures (wax, stone, try-in). Moreover, the precise design and customization of the substructure is presented, with the original and engineered shape for the retention of the silicone. The time and cost saving results of this protocol are presented together with a discussion of the main design features that make the prosthesis a stable and reproducible system to improve rehabilitation of patients with auricular defects or absence.

Design and evaluation of a four-dimensional interface for air traffic control

Abstract The increasing complexity of the air traffic system is pushing towards the development of innovative and more automated tools conceived to manage it. In this scenario, an important role is played by HCI (human—computer interfaces) used by air traffic controllers and operators to visualize and interact with air traffic data. Currently, information about three-dimensional (3D) scenery is displayed with a two-dimensional representation. This paper presents the design, development, and evaluation of an innovative interface for air traffic control (ATC) based on a four-dimensional (4D) (3D space+time) visualization display. The proposed interface allows the operator to perceive all the information, including meteorological conditions, that is useful for TWR/APP (ToWeR/APProach) control in a unique 4D synthetic reconstruction of the airport area. Particular attention is dedicated to the fourth variable, time, which is a fundamental parameter in ATC. A simple and fast trajectory prediction algorithm has been implemented in order to provide the operator with an effective ‘user assistance’ tool in conflict detection activities. The interface has been evaluated by performing test simulations and surveys were used to collect results and useful advice for its future development.