3D planning of ear prosthesis and navigated flapless surgery for craniofacial implants: A pilot study.

New 3D digital technologies can be applied to implant-supported ear prostheses to restore anatomical structures damaged by cancer, dysplasia, or trauma. However, several factors influence the accuracy of implant positioning using a cranial template. This pilot study describes an innovative navigated flapless surgery for craniofacial implants, prosthetically guided by 3D planning of the ear prosthesis. Laser surface scanning of the face allowed for mapping of the healthy ear onto the defect site, and projection of the volume and position of the final prosthesis. The projected ear volume was superimposed on the skull bone image obtained by cone-beam computed tomography (CBCT), performed with the navigation system marker plate positioned in the patient's mouth. The craniofacial implants were fitted optimally to the ear prosthesis. After system calibration, real-time navigated implant placement based on the virtual planning was performed with minimally invasive flapless surgery under local anesthesia. After 3 months of healing, digital impressions of the implants were made, and the digital manufacturing workflow was completed to manufacture the ear prosthesis anchored to the craniofacial implants. The proposed digital method facilitated implant positioning during flapless surgery, improving the ear prosthesis manufacturing process and reducing operation time, patient morbidity, and related costs. This protocol avoids the need for a reference tool fixed in the cranial bone, as is usually required for maxillofacial surgery, and confirmed that surgical navigation is useful for guiding the insertion of craniofacial implants during flapless surgery.

Influence of preparation design and spacing parameters on the risk of chipping of crowns made with Cerec Bluecam before cementation.

PURPOSE: To evaluate the influence of the preparation design and spacing parameters on the risk of chipping of crowns made by CEREC Bluecam before cementation. METHODS: A knife-edge preparation and a chamfer preparation were made on upper premolars. The teeth were scanned and two Co-Cr alloy replicas were made. Fifteen full crowns were manufactured for four groups using CEREC. The groups differed in type of preparation (knife-edge (KE) or chamfer (CHA)) and spacing parameters: spacer (0 or 150µm), marginal adhesive gap (10 or 50 or 150µm) and margin thickness (0 or 300µm). The four groups were: CHA 150 (spacer)- 50 (marginal adhesive gap)- 0 (margin thickness), KE 150-50-0, KE 150-50-300 and KE 150-150-300. The crowns were loaded before cementation by using an Instron machine to simulate the masticatory load applied during a trial. Differences in means were compared using two-way ANOVA and a post-hoc test (Tukey Test). The level of significance was set at P=0.05. RESULTS: The fracture values, ordered from least to most resistant, were: KE 150-50-300 group, CHA 150-50-0 group, KE 150-50-0 group and KE 150-150-300 group. Two-way ANOVA revealed statistically significant differences between pairs of means (p<0.05). Tukey's test showed that restorations of the KE 150-150-300 group can withstand a load significantly higher than that of other groups (p<0.01). In this group, the failures were mostly minor chippings, while the other groups had mostly major chippings and fractures. CONCLUSIONS: Marginal adhesive gap can affect the trial of a full crown.

Customized hybrid biomimetic hydroxyapatite scaffold for bone tissue regeneration.

Three-dimension (3D) scaffolds for bone tissue regeneration were produced combining three different phases: nanometric hydroxyapatite (HA) was synthesized by precipitation method and the crystals nucleation took place directly within collagen fibrils following a biologically inspired mineralization process; polycaprolactone was employed to give the material a 3D structure. The chemico-physical analysis carried out to test the material's properties and composition revealed a high similarity in composition and morphology with biologically mineralized collagen fibrils and a scaffold degradation pattern suitable for physiological processes. The micro- computerized tomography (micro-CT) showed 53.53% porosity and a 97.86% mean interconnected pores. Computer-aided design and computer-aided manufacturing (CAD-CAM) technology was used for molding the scaffold's volume (design/shape) and for guiding the surgical procedure (cutting guides). The custom made scaffolds were implanted in sheep mandible using prototyped surgical guides and customized bone plates. After three months healing, scanning electron microscopy (SEM) analysis of the explanted scaffold revealed a massive cell seeding of the scaffold, with cell infiltration within the scaffold's interconnected pores. The micro-CT of the explanted construct showed a good match between the scaffold and the adjacent host's bone, to shield the implant primary stability. Histology confirmed cell penetration and widely documented neoangiogenesis within the entire scaffold's volume. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 723-734, 2017.

Mandibular reconstruction using fibula free flap harvested using a customised cutting guide: how we do it.

Free fibula flap is routinely used for mandibular reconstructions. For contouring the flap, multiple osteotomies should be shaped to reproduce the native mandibular contour. The bone segments should be fixed using a reconstructive plate. This plate is usually manually bent by the surgeon during surgery. This method is efficient, but during reconstruction it is complicated to reproduce the complex 3D conformation of the mandible and recreate a normal morphology with a mandibular profile as similar as possible to the original; any aberration in its structural alignment may lead to aesthetic and function alterations due to malocclusion or temporomandibular disorders. In order to achieve better morphological and functional outcomes, we have performed a customised flap harvest using cutting guides. This study demonstrates how we have performed customised mandibular reconstruction using CAD-CAM fibular cutting guides in 20 patients undergoing oncological segmental resection.

Mesenchymal stem cells and platelet gel improve bone deposition within CAD-CAM custom-made ceramic HA scaffolds for condyle substitution.

PURPOSE: This study evaluated the efficacy of a regenerative approach using mesenchymal stem cells (MSCs) and CAD-CAM customized pure and porous hydroxyapatite (HA) scaffolds to replace the temporomandibular joint (TMJ) condyle. METHODS: Pure HA scaffolds with a 70% total porosity volume were prototyped using CAD-CAM technology to replace the two temporomandibular condyles (left and right) of the same animal. MSCs were derived from the aspirated iliac crest bone marrow, and platelets were obtained from the venous blood of the sheep. Custom-made surgical guides were created by direct metal laser sintering and were used to export the virtual planning of the bone cut lines into the surgical environment. Sheep were sacrificed 4 months postoperatively. The HA scaffolds were explanted, histological specimens were prepared, and histomorphometric analysis was performed. RESULTS: Analysis of the porosity reduction for apposition of newly formed bone showed a statistically significant difference in bone formation between condyles loaded with MSC and condyles without (P < 0.05). The bone ingrowth (BI) relative values of split-mouth comparison (right versus left side) showed a significant difference between condyles with and without MSCs (P < 0.05). Analysis of the test and control sides in the same animal using a split-mouth study design was performed; the condyle with MSCs showed greater bone formation. CONCLUSION: The split-mouth design confirmed an increment of bone regeneration into the HA scaffold of up to 797% upon application of MSCs.

CAD-CAM prosthetically guided bone regeneration using preformed titanium mesh for the reconstruction of atrophic maxillary arches.

The protocol presented here is intended to minimise the intervention in bone reconstruction surgery when severe atrophy or deformity is present in the maxillary arches. A patient underwent augmentation of an atrophic maxillary arch using titanium mesh and particulate autogenous plus bovine demineralised bone. After computed tomography data elaboration, computer-aided design and computer-aided machining were used to plan the augmentation of bone volume to improve the implant position needed to support the final dental prosthesis. The augmented maxilla was rapidly prototyped in plastic, and the titanium mesh was tested on this model before the surgical intervention. Then, the preformed titanium mesh was implanted in the maxillary arch with bone grafting. The bone was augmented relative to the position of the implants for the definitive fixed implant-supported rehabilitation. The protocol presented here is a viable, reproducible way to determine the correct bone augmentation for the final implant-supported prosthetic rehabilitation.

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.

Direct metal laser sintering (DMLS) of a customized titanium mesh for prosthetically guided bone regeneration of atrophic maxillary arches.

This study describes a protocol for the direct manufacturing of a customized titanium mesh using CAD-CAM procedures and rapid prototyping to augment maxillary bone and minimize surgery when severe atrophy or post-oncological deformities are present. Titanium mesh and particulate autogenous plus bovine demineralised bone were planned for patient rehabilitation. Bone augmentation planning was performed using the pre-op CT data set in relation to the prosthetic demands, minimizing the bone volume to augment at the minimum necessary for implants. The containment mesh design was used to prototype the 0.6 mm thickness customized titanium mesh, by direct metal laser sintering. The levels of regenerated bone were calculated using the post-op CT data set, through comparison with the pre-op CT data set. The mean vertical height difference of the crestal bone was 2.57 mm, while the mean buccal-palatal dimension of thickness difference was 3.41 mm. All planned implants were positioned after an 8 month healing period using two-step implant surgery, and finally restored with a partial fixed prosthesis. We present a viable and reproducible method to determine the correct bone augmentation prior to implant placement and CAD-CAM to produce a customized direct laser-sintered titanium mesh that can be used for bone regeneration.

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.

CAD-CAM construction of a provisional nasal prosthesis after ablative tumour surgery of the nose: a pilot case report.

The computer-aided design of a nasal prosthesis based on pre-operative virtual laser scanning of the affected site was virtually adapted to the post-operative laser-scanned surface. The designed volume of the nose was rapidly prototyped and used to fabricate a provisional prosthesis and a computed tomography diagnostic template to check the available premaxilla bone for implants. The mould for the nasal prosthesis was prototyped using a computer-aided design and manufacturing (CAD-CAM) procedure. In addition, the mesiostructure of an eyeglasses-supported provisional prosthesis was also designed and prototyped using CAD-CAM procedures.

CAD-CAM construction of an auricular template for craniofacial implant positioning: a novel approach to diagnosis.

A novel approach to the diagnosis of bone available for craniofacial implant positioning is discussed in a case that required ear ablation for tumor removal. A mirrored volume of the healthy ear was rapidly prototyped for a clinical trial in an appropriate position relative to the patient's face. Three ideal positions for the implant were chosen in the inner of the volume of the mirrored ear. The same positions were transferred to a diagnostic template that was rapidly prototyped with a positioning arm extending to the zygomatic arch. Computed tomography (CT) revealed errors in the planning of the implant position and, as a clinical consequence, an implant site was excluded from surgical planning. A virtual elaboration for maxillofacial implant positioning was used to define the correct implant site in relation to the available bone, and two craniofacial implants were correctly positioned in the temporal bone.

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.

Gingival hyperplasia around implants in the maxilla and jaw reconstructed by fibula free flap.

A recurring problem during prosthetic rehabilitation following reconstruction by means of a vascularized fibula flap, after ablation of tumors affecting the facial skeleton, is the hyperplastic granulomatous reactive tissue that forms around the prosthetic abutments of the implant. The features of this phenomenon seem to be directly related to the characteristics of the peri-implant tissue and to the material from which the prosthetic abutments are manufactured. Two main ways of avoiding this are proposed. 1) Skin grafts around implants seem to inhibit the overgrowth of granulomatous tissue. 2) Acrylic provisionals should be avoided and substituted with complete metal-ceramic restoration.

Maxillofacial rehabilitation after rhinectomy using two different treatment options: clinical reports.

The aim of these clinical reports was to describe two different approaches to prosthetic rehabilitation after facial disfigurement because of a total rhinectomy. A man with a total rhinectomy was scheduled for craniofacial implants in the nasal residual defect. Three oral implants were used instead of craniofacial ones. A conventional framework was designed to connect the prosthesis to the implant abutments in the anterior nasal floor, and a custom-made ball attachment was positioned in the glabella abutment. A woman with a free rectum abdomis flap covering the defect of the middle face was scheduled for a nasal prosthesis. A titanium framework with a novel connection between the eyeglasses and the prosthesis was manufactured. The two clinical reports presented in this article illustrate favourable clinical treatment outcomes in the rehabilitation of disfigurement.

The prosthetically guided osteodistraction of the mandible in the microvascular bone reconstruction after cancer surgery.

The rehabilitation of the mandible after ablation cancer surgery is a challenge. Furthermore, osteodistraction in the microvascular fibula flap makes it difficult to predict adequate bone lengthening. The aim of this article is to evaluate a protocol used to manufacture templates for measuring osteodistraction, in terms of force vectors and definitive height. An accurate prosthetic wax-up with guide pins measuring the quantity of bone lengthening must be performed to manufacture the template. This device may be used to establish the end of the osteo-distraction in respect to the vertical dimension of the definitive occlusion.

Home care maintenance protocol for ear prostheses.

Hygienic home care maintenance for patients who have received a maxillofacial prosthesis is very important in order to secure a long-term success of a facial rehabilitation. Craniofacial implant therapy requires a specific protocol to care for the peri-implant tissues and material used for the prosthesis. This article presents the maintenance and care protocol for proper follow-up management of a maxillofacial ear prosthesis. Home care methods for the prosthesis hygiene are described, including: the insertion and the disconnection of the ear prosthesis, hygiene of the bar abutments before and after postdefinitive connection to the craniofacial fixtures, washing of the device, professional follow-up.

Residual facial disfigurement after the ablative surgery of a lachrymal gland carcinoma: a clinical report of the prosthetic rehabilitation.

Facial disfigurement after ablative surgery of a massive adeno-carcinoma of the lachrymal gland is described. A rehabilitation with a maxillofacial prosthesis was proposed to restore the aesthetic appearance of the patient without inserting craniofacial implants. Retention of a maxillofacial prosthesis, that is not anchored to implants, depends on the use of adhesives or on mechanical devices like glasses. This clinic report describes a residual anatomic defect which allowed for the double choice of wearing the facial prosthesis both with or without glasses. A retentive backside of the prosthesis was developed to engage the facial defect undercuts, which enhanced retention when the patient used the skin glue without glasses. A unique foam silicone was utilized to reduce the weight of the prosthesis and to permit its retention only by skin adhesive.

[New aesthetic results with auricular prosthesis: two case reports]. / Nuovi risultati estetici con epitesi auricolari. Due casi clinici.

The extrinsic and intrinsic coloration of maxillo-facial silicone elastomers has always been a challenge for the clinician in order to obtain a perfect, durable integration with the surrounding skin tissues. This preliminary report describes the method for obtaining good aestethetic results for maxillo-facial prosthesis. This study shows the aesthetic results of a new silicone for the laboratory technique of creating color of the basis for a maxillo-facial prosthesis, with a good matching with human skin. The technique is useful for the direct extrinsic coloration of the surface onto the skin of the patient by means of the RTV version of the same silicone. The technological properties of this material also make it easy to reproduce the emerging profile of the prosthesis from the human skin, avoiding anaesthetic overcounturings. The 12 month follow-up shows excellent and stable aesthetic results, which are not influenced by home care procedures and by the weathering effect on color and on physical properties.