Leonardo Ciocca

Translucency of zirconia copings made with different CAD/CAM systems.

STATEMENT OF PROBLEM Zirconia cores are reported to be less translucent than glass, lithium disilicate, or alumina cores. This could affect the esthetic appearance and the clinical choices made when using zirconia-based restorations. PURPOSE The purpose of this in vitro study was to evaluate the translucency of zirconia copings for single crowns fabricated using different CAD/CAM systems, using lithium disilicate glass ceramic as a control. MATERIAL AND METHODS Using impressions made from a stainless steel complete-crown master die, 9 stone cast replicas were fabricated, numbered, and distributed into 8 ceramic ZrO(2) CAD/CAM system groups (Lava Frame 0.3 and 0.5, IPS e.max ZirCAD, VITA YZ, Procera AllZircon, Digizon, DC Zircon, and Cercon Base) and to a lithium disilicate glass-ceramic control group (IPS e.max Press) using a simple computer-generated randomization method. From each die, the manufacturers authorized milling centers supplied 5 copings per group without applying any dying technique to the ceramic base material. The copings were prepared to allow for a 40-mum cement layer and were of different thicknesses according to system specifications. Translucency was measured by the direct transmission method with a digital photoradiometer mounted in a dark chamber. The light source was a 150-W halogen lamp beam. Measurements were repeated 3 times for each specimen. Data obtained were analyzed using 1-way ANOVA and the Bonferroni multiple comparison test (alpha=.05). RESULTS Among ZrO(2) copings, Lava (0.3 mm and 0.5 mm thick) showed the highest (P<.05) values of translucency measured as light flow units (3.572 + or - 018 x 10(3) lx and 3.181 + or - 0.13 x 10(3) lx, respectively). These values represent 71.7% and 63.9%, respectively, of the glass-ceramic control group (4.98 x 10(3) lx). CONCLUSIONS All ZrO(2) copings demonstrated different levels of light transmission, with the 2 Lava specimens showing the highest values. Translucency of zirconia copings was significantly lower (P=.001) than that of the lithium disilicate glass-ceramic control.

CAD/CAM and rapid prototyped scaffold construction for bone regenerative medicine and surgical transfer of virtual planning: A pilot study

We developed a model to test new bone constructs to replace spare skeletal segments originating from new generation scaffolds for bone marrow-derived mesenchymal stem cells. Using computed tomography (CT) data, scaffolds were defined using computer-aided design/computer-aided manufacturing (CAD/CAM) for rapid prototyping by three-dimensional (3D) printing. A bone defect was created in pig mandible ramus by condyle resection for CT and CAD/CAM elaboration of bone volume for cutting and scaffold restoration. The protocol produced a perfect-fitting bone substitute model for rapid prototyped hydroxyapatite (HA) scaffolds. A surgical guide system was developed to accurately reproduce virtually planned bone sectioning procedures in animal models to obtain a perfect fit during surgery.

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.

CAD/CAM ear model and virtual construction of the mold

This article describes a technique to make an implant-retained maxillofacial prosthesis using CAD/CAM technology and a rapid prototyping machine. The primary advantage of this technique is virtual 3-dimensional integration of the defective surface with the mirrored and digitalized normal ear. Making an impression of the defective side is not necessary, because only the position of the implants must be recorded to develop the bar for the retention of the prosthesis. This procedure allows positioning of the ear straight onto the computer screen, eliminating the diagnostic waxing, and the fabrication of the stone mold is not necessary because of the rapid prototyping process.

Prosthetically guided maxillofacial surgery: evaluation of the accuracy of a surgical guide and custom-made bone plate in oncology patients after mandibular reconstruction.

Background: The aim of the present study was to evaluate the accuracy of prosthetically guided maxillofacial surgery in reconstructing the mandible with a free vascularized flap using custom-made bone plates and a surgical guide to cut the mandible and fibula. Methods: The surgical protocol was applied in a study group of seven consecutive mandibular-reconstructed patients who were compared with a control group treated using the standard preplating technique on stereolithographic models (indirect computer-aided design/computer-aided manufacturing method). The precision of both surgical techniques (prosthetically guided maxillofacial surgery and indirect computer-aided design/computer-aided manufacturing procedure) was evaluated by comparing preoperative and postoperative computed tomographic data and assessment of specific landmarks. Results: With regard to midline deviation, no significant difference was documented between the test and control groups. With regard to mandibular angle shift, only one left angle shift on the lateral plane showed a statistically significant difference between the groups. With regard to angular deviation of the body axis, the data showed a significant difference in the arch deviation. All patients in the control group registered greater than 8 degrees of deviation, determining a facial contracture of the external profile at the lower margin of the mandible. With regard to condylar position, the postoperative condylar position was better in the test group than in the control group, although no significant difference was detected. Conclusions: The new protocol for mandibular reconstruction using computer-aided design/computer-aided manufacturing prosthetically guided maxillofacial surgery to construct custom-made guides and plates may represent a viable method of reproducing the patient’s anatomical contour, giving the surgeon better procedural control and reducing procedure time. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

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.

Accuracy of fibular sectioning and insertion into a rapid-prototyped bone plate, for mandibular reconstruction using CAD-CAM technology.

Modern techniques of mandibular reconstruction, such as CAD-CAM technology and rapid prototyping, offer new means by which reconstructive surgery can be planned to optimise aesthetic outcomes and prosthetic rehabilitation. The high degree of accuracy afforded by these approaches is principally attributable to high-precision fibular sectioning and insertion of the bone into a customised bone plate. CAD-CAM mandibular reconstruction procedures using vascularised bone free-flap transfers were performed on 10 patients with benign or malignant neoplasms. Five were not treated with the aid of CAD-CAM technology, and served as the control group. Five were scheduled for maxillofacial surgery using surgical cutting guides and customised bone plates. A generalised linear model for linear measures was used to compare the accuracy of reconstruction between the two groups. A difference, even though not significant, in the lateral shift of the mesial and distal positions of the fibular units was evident between groups. CAD-CAM-generated fibular surgical guides afford improved accuracy when used to restore native anatomy, especially in the context of mandibular arch restoration, and both operating room time and related costs are reduced during fibular sectioning.

The CAD–CAM technique for mandibular reconstruction: An 18 patients oncological case-series

BACKGROUND Modern techniques for mandibular reconstruction, such as CAD-CAM, offer new solutions for planning of reconstructive surgery in relation to the aesthetic outcome and the prosthetic rehabilitation. METHODS CAD-CAM reconstruction procedures using vascularised bone free-flap transfers and surgical guides to cut the mandible and fibula were performed in 18 cases of neoplasms. The planned surgery was used to design and manufacture customised surgical devices. RESULTS The mean follow-up was 12 months. All patients, except one, are alive without disease at the time of writing. Reconstructive microvascular flap survival was 100%. No major or minor microvascular complication occurred. No donor site complication was observed. CONCLUSIONS CAD-CAM technology is a very useful way to obtain the native morphology of the mandible, especially when both bi-dimensional and tri-dimensional defects occur. The reconstruction protocol presented offers several benefits and few disadvantages, which are discussed in the article.

Immediate facial rehabilitation in cancer patients using CAD–CAM and rapid prototyping technology: a pilot study

PurposeThis study describes the workflow in a procedure to create a provisional facial prosthesis for cancer patients using digital and rapid prototyping technologies without the need for supporting craniofacial implants.Materials and methodsAn integrated workflow procedure aimed at the construction of provisional silicone prosthesis was used to rehabilitate a facial disfigurement in a patient who had undergone ablative surgery of the midface. A laser scan of the defect was obtained, and a digital model of the patient′s face was constructed using virtual mirroring of the healthy side and referencing the “Nose Digital Library.”ResultsThe missing volume of the face was reconstructed, and a rapid-prototyped mold was devised to process the silicone prosthesis. A provisional eyeglasses-supported prosthesis designed with a CAD/CAM-projected titanium substructure was connected using the micro-components of implant prosthetic devices.ConclusionsThe workflow described herein offers a viable procedure for quickly restoring facial defects by means of provisional prosthetic rehabilitation.

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.