Applications of CAD/CAM Technology for Craniofacial Implants Placement and Manufacturing of Auricular Prostheses-Systematic Review.

This systematic review was aimed at gathering the clinical and technical applications of CAD/CAM technology for craniofacial implant placement and processing of auricular prostheses based on clinical cases. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, an electronic data search was performed. Human clinical studies utilizing digital planning, designing, and printing systems for craniofacial implant placement and processing of auricular prostheses for prosthetic rehabilitation of auricular defects were included. Following a data search, a total of 36 clinical human studies were included, which were digitally planned and executed through various virtual software to rehabilitate auricular defects. Preoperative data were collected mainly through computed tomography scans (CT scans) (55 cases); meanwhile, the most common laser scanners were the 3dMDface System (3dMD LLC, Atlanta, Georgia, USA) (6 cases) and the 3 Shape scanner (3 Shape, Copenhagen, Denmark) (6 cases). The most common digital design software are Mimics Software (Mimics Innovation Suite, Materialize, Leuven, Belgium) (18 cases), Freeform software (Freeform, NC, USA) (13 cases), and 3 Shape software (3 Shape, Copenhagen, Denmark) (12 cases). Surgical templates were designed and utilized in 35 cases to place 88 craniofacial implants in auricular defect areas. The most common craniofacial implants were Vistafix craniofacial implants (Entific Medical Systems, Goteborg, Sweden) in 22 cases. A surgical navigation system was used to place 20 craniofacial implants in the mastoid bone. Digital applications of CAD/CAM technology include, but are not limited to, study models, mirrored replicas of intact ears, molds, retentive attachments, customized implants, substructures, and silicone prostheses. The included studies demonstrated a predictable clinical outcome, reduced the patient's visits, and completed the prosthetic rehabilitation in reasonable time and at reasonable cost. However, equipment costs and trained technical staff were highlighted as possible limitations to the use of CAD/CAM systems.

Effect of the Advanced Cranial and Craniofacial Implant Fabrication on Their Degradation Affinity.

Biodegradable craniofacial and cranial implants are a new aspect in terms of reducing potential complications, especially in the long term after surgery. They are also an important contribution in the field of surgical reconstructions for children, for whom it is important to restore natural bone in a relatively short time, due to the continuous growth of bones. The aim of this study was to verify the impact of the technology on biodegradability and to estimate the risk of inappropriate implant resorption time, which is an important aspect necessary to select prototypes of implants for in vivo testing. Prototypes of implants were made using two technologies: 3D printing using a PLDLA: poly(L-co-D,L lactide) (PLDLA) filament containing hydroxyapatite nanoparticles, and injection using PLDLA. After the radiation sterilization process, they were subjected to in vitro degradation under accelerated conditions. As part of this study, the in vitro degradation of newly developed biodegradable implant technologies was assessed in accordance with the guidelines of European standards. It was found that the implant manufacturing process had a significant impact on the degradation time under simulated conditions in various media. Implants made using the injection technique were characterized by lower susceptibility to degradation media compared to the 3D-printed implant under accelerated conditions.

Half sphere and single clip-bar retained implant supported silicone auricular prosthesis.

Implant supported auricular prosthesis can be retained by several mechanical means, one of them being the Hader bar and clip system. Conventionally two or more rider clips are used. This technique describes a modified Hader bar design to maintain retention while eliminating the requirement of a second clip, significantly bringing down cost.

Outcome of implants placed to retain craniofacial prostheses - A retrospective cohort study with a follow-up of up to 30 years.

OBJECTIVES: To retrospectively assess the treatment outcomes of endosseous implants placed to retain craniofacial prostheses. MATERIAL AND METHODS: Patients with craniofacial defects resulting from congenital disease, trauma, or oncologic treatment had implant retained prostheses placed in the mastoid, orbital, or nasal region and then assessed over a period of up to 30 years. Implant survival rates were calculated with the Kaplan-Meier method. Clinical assessments consisted of scoring skin reactions under the prosthesis and the peri-implant skin reactions. Possible risk factors for implant loss were identified. Patient satisfaction was evaluated using a 10-point VAS-scale. RESULTS: A total of 525 implants placed in 201 patients were included. The median follow up was 71 months (IQR 28-174 months). Implants placed in the mastoid and nasal region showed the highest overall implant survival rates (10-year implant survival rates of 93.7% and 92.5%, respectively), while the orbital implants had the lowest overall survival rate (84.2%). Radiotherapy was a significant risk factor for implant loss (HR 3.14, p < 0.001). No differences in implant loss were found between pre- and post-operative radiotherapy (p = 0.89). Soft tissue problems were not frequently encountered, and the patients were highly satisfied with their implant-retained prosthesis. CONCLUSION: Implants used to retain craniofacial prostheses have high survival and patient satisfaction rates and can thus be considered as a predictable treatment option. Radiation is the most important risk factor for implant loss.

9-Year Follow-Up on Maxillofacial Implant-Supported Framework Designed to Accommodate Childhood Growth.

This clinical report focuses on the challenges and solutions for a child subjected to craniofacial trauma from a wild hyena biting off his nose and anterior maxilla. Unique considerations in prosthodontics and biomedical engineering were required based on future craniofacial growth and development of the child. The physical requirement of a maximum retentive prosthesis for an active, athletic child required unique engineering designs and executions. The sequence of treatment and prosthesis fabrication are detailed. The patient has been followed for 9 years without physiologic complications and only minor prosthodontic complications.

Systematic Review of Clinical Applications of CAD/CAM Technology for Craniofacial Implants Placement and Manufacturing of Orbital Prostheses.

This systematic review was aimed at gathering technical and clinical applications of CAD/CAM technology for the preoperative planning of craniofacial implants placement, designing of molds and substructures and fabrication of orbital prostheses. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, an electronic search was executed. Human studies that utilized digital planning systems for the prosthetic rehabilitation of orbital defects were included. A total of 16 studies of 30 clinical cases, which were virtually planned through various digital planning and designing software, were included. The most common preoperative data required for digital planning were CT scans in 15 cases, the 3DSS-STD-II scanning system in 5 cases, an Artec Color 3D scanner in 3 cases and a NextEngine Desktop 3D laser scanner in 2 cases. Meanwhile, the digital designing software were Ease Orbital Implant Planning EOIPlan software in eight cases, Geomagic software in eight cases, Simplant software in four cases and Artec Studio 12 Professional in three cases. Surgical templates were fabricated for 12 cases to place 41 craniofacial implants in the orbital defect area. An image-guided surgical navigation system was utilized for the placement of five orbital implants in two cases. Digital designing and printing systems were reported for the preoperative planning of craniofacial implants placement, designing of molds and substructures and fabrication of orbital prostheses. The studies concluded that the digital planning, designing and fabrication of orbital prostheses reduce the clinical and laboratory times, reduces patient visits and provide a satisfactory outcome; however, technical skills and equipment costs are posing limitations on the use of these digital systems.

Craniofacial implants in a failed autologous reconstruction of microtia: a case report.

Plastic surgical reconstruction is considered to be the gold standard for the repair of microtia as the results are permanent and constructed from the patient's own tissue; however, the multiple surgeries required and the difficulty in attaining adequate cosmetic results often result in patients choosing a prosthesis as a long-term rehabilitation. Advances in osseointegration in the craniofacial region have improved the outcomes with auricular prosthetics by providing a reliable method of attachment of the prosthesis and increasing patient acceptance. A case presentation illustrates the results of both treatment modalities and examines the outcomes on the same patient.

Systematic Review of Clinical Applications of CAD/CAM Technology for Craniofacial Implants Placement and Manufacturing of Nasal Prostheses.

The aim of this systematic review was to gather the clinical and laboratory applications of CAD/CAM technology for preoperative planning, designing of an attachment system, and manufacturing of nasal prostheses. According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, an electronic search was carried out. Only human clinical studies involving digital planning for the rehabilitation of facial defects were included. A total of 21 studies were included with 23 patients, which were virtually planned through different planning software. The most common preoperative data for digital planning were CT scans in nine cases, CBCT in six cases, and laser scans in six cases. The reported planning softwares were Mimics in six cases, Geomagic Studio software in six cases, ZBrush in four cases, and Freeform plus software in four cases. Ten surgical templates were designed and printed to place 36 implants after digital planning, while post-operative assessment was done in two cases to check the accuracy of planned implants. Digital 3D planning software was reported for presurgical planning and craniofacial implants placement, fabrication of molds, designing of implants, designing of retentive attachments, and printing of silicone prostheses. Digital technology has been claimed to reduce the clinical and laboratory time; however, the equipment cost is still one of the limitations.

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.

Prosthetic rehabilitation of the geriatric oncologic rhinectomy patient utilizing a craniofacial implant-retained nasal prosthesis.

This clinical report describes the expeditious treatment of a geriatric patient with squamous cell carcinoma of the nose treated with total rhinectomy, craniofacial implant placement, and a nasal prosthesis.

Implant prognosis in irradiated versus non-irradiated nasal, orbital and auricular sites.

The purpose of this systematic review was to evaluate implant survival in irradiated nasal, auricular, orbital sites and to compare them with non-irradiated respective sites. Four electronic databases and seven related journals were searched until December and March 2018, respectively. A total of 7892 articles were identified, 18 of which were included in this review; one non-randomized clinical trial, two prospective cohort, eight retrospective cohort and seven cross-sectional studies. Using the ROBIN-I Cochrane tool for risk assessment, 13 studies were judged at serious, one at moderate and four at critical risk of bias. Thirteen were included in 18 meta-analyses, the results of which showed a significant difference between irradiated and non-irradiated sites, favouring non-irradiated with risk ratio (RR) = 0.93, 95% confidence interval (CI) 0.89-0.97, P=0.001. Comparisons among nasal, auricular and orbital sites revealed no significant differences, whether in irradiated or non-irradiated patients at P<0.05. Hence, it was concluded that, within the limitations of this review, survival of craniofacial implants is negatively affected by radiotherapy, especially in orbital sites. Level of evidence is moderate. Therefore, further prospective cohort studies with calculated sample sizes, restricted or properly managed confounders and no deviations from intended interventions might produce different results.

Bilateral auricular reconstruction with osseointegrated implant-retained prostheses. Optimization of aesthetic outcomes using virtual planning.

Auricular reconstruction in microtia patients is challenging, particularly in bilateral cases. The use of osseointegrated implants is a safe and effective way to retain the auricular prostheses. With the help of virtual planning we can produce more predictable results with better aesthetic outcomes. We present a case of an 8-year-old bilateral microtia patient who underwent auricular reconstruction with implant-retained prostheses, using virtual planning. Using stereolithographic models and surgical guides was also very helpful to achieve excellent results.

Silicon nitride enhances osteoprogenitor cell growth and differentiation via increased surface energy and formation of amide and nanocrystalline HA for craniofacial reconstruction.

The bioactive silicon nitride (Si3N4) has been FDA cleared for use as spinal intervertebral arthrodesis devices. Because its surface properties promote bone ongrowth and ingrowth, it also has the potential to benefit craniofacial reconstruction. Thus, the aim of this work was to determine whether the surface properties of Si3N4 could enhance the osteoblast cell growth, differentiation and nucleation of hydroxyapatite (HA) crystals compared to conventional implant materials such as titanium (Ti) and polyether ether ketone (PEEK). X-ray absorbance near-edge structure analysis (XANES) indicated the presence of Si-Si, Si-O and Si-N bonding. Surface wettability studies confirmed that Si3N4 exhibits the lowest contact angle and highest surface energy. Cell culture studies showed that osteoblast growth was enhanced on Si3N4 after 1 day and up to 7 days. Si3N4 surface induced highest surface coverage and thickness of nanocrystalline HA (211) and (203) in cell-free in vitro studies after 7 days of culture. Raman spectroscopy analysis confirmed the presence of surface functional groups consisting of phosphate and carbonate species. Interestingly, Si3N4 surface showed amide and hydroxyproline groups, the precursors to collagen, which were not observed on Ti and PEEK surfaces. Furthermore, Si3N4 surface indicated high expression of RUNX2, enhanced cell differentiation and dense collagenous ECM after 30 days of the in vitro study. The present study concluded that Si3N4 surface enhances osteoprogenitor cell adhesion, growth, RUNX2 expression and ECM formation via the coupled effects of higher surface energy and the presence of amide and nanocrystalline HA functional groups.

Two auricular epithesis surgical cases retained by a custom titanium implant: result at four years.

INTRODUCTION: This article aims at describing the four-year outcome of a surgical procedure implanting a patient specific epithesis system in two patients. TECHNICAL NOTE: After virtual 3D reconstruction of the anatomy and mirroring of the healthy ear, the position of the three Locator® attachments were optimized in the software to embed them as accurately as possible in the planned episthesis antihelix. The personalized plate bearing the three Locator® implants was then manufactured. Ten osteosynthesis screws were placed around the abutments to ensure bone anchorage. Post-operative antibiotic therapy was prescribed for the duration of ten days. The episthesis was placed two months post-operatively. The follow-up for each patient was 65 and 57 months respectively with no complications to report. CONCLUSION: 3D planning assists the surgeon and eliminates several constraints related to the placement of bone implants. It assists the surgical procedure and improves both the aesthetics and functional result of the surgery.

Long-term outcomes of craniofacial implants for the restoration of facial defects.

The aim of this study was to evaluate the long-term survival of craniofacial implants and prostheses and to identify factors associated with failure in a cohort of patients. A 25-year retrospective analysis was conducted at Royal Melbourne Hospital. Data included demographic characteristics, age, site and cause of the deformity, and number and survival of implants. Odds ratios were calculated and event-to-time Kaplan-Meier analyses performed. One hundred and ten patients were included (341 implants); their mean age was 46.2 years. The overall implant survival rate was 79.5% (mean follow-up 10.6 years). Temporal implants had the highest success rate (97.0%), followed by nasal implants (87.5%) and orbital implants (63.3%); differences were statistically significant (P<0.0001 and P=0.033, respectively). Kaplan-Meier analyses to determine long-term implant and prosthesis survival found temporal implants had the highest prosthetic (P<0.0001) and implant survival (P<0.0001). Patients with congenital deformities demonstrated the highest success rate. Radiotherapy was found to increase the risk of implant failure (P=0.02). Craniofacial implant-retained prostheses are a reliable and effective option for the restoration of facial defects, with good long-term success rates. Orbital implants and those placed post oncological surgery have a higher failure rate.

Refabrication of an implant-retained auricular prosthesis using clip attachment pickup technique.

Increased patient acceptance and widespread use have led to a greater demand for refabrication of existing maxillofacial prostheses exhibiting wear and tear. Refabricating an osseointegrated implant-retained silicone auricular prosthesis on the existing Hader bar is a challenging task if it is performed without removing it. Therefore, an attachment level impression method is utilized for the refabrication of a new prosthesis on an existing Hader bar framework without removing it from the patient's defect. This case report discusses a modification of the Mahidol University technique. This modification provides a simple, speedy, and convenient method through which the relation between the metal framework and attachments could be obtained precisely. This precision allowed for easy fabrication of the acrylic housing, which in turn results in better adaptation of the auricular prosthesis to the patient's face. Therefore, this technique offers advantages to both the prosthetist in fabrication and the patient in facilitating him continue to wear his existing implant-retained prosthesis during refabrication process.

Retention systems for extraoral maxillofacial prosthetic implants: a critical review.

We describe the techniques available for retention of implant-supported prostheses: bar-clips, O-rings, and magnets. We present reported preferences and, although this is limited by the heterogeneity of methods used and patients studied, we hope we have identified the best retention systems for maxillofacial prosthetic implants. If practitioners know the advantages and disadvantages of each system, they can choose the most natural and comfortable prosthesis. We searched the PubMed and Scopus databases, and restricted our search to papers published 2001-13. MeSH terms used were Maxillofacial prosthesis and Craniofacial prosthesis OR Craniofacial prostheses. We found a total of 2630 papers, and after duplicates had been removed we analysed the rest and found 25 papers for review. Of these, 12 were excluded because they were case reports or non-systematic reviews. Of the remaining 13, 10 described group analyses and seemed appropriate to find practitioner's choices, as cited in the abstract (n=1611 prostheses). Three papers did not mention the type of prosthetic connection used, so were excluded. The most popular choices for different conditions were analysed, though the sites and retention systems were not specified in all 10 papers. The bar-clip system was the most used in auricular (6/10 papers) and nasal prostheses (4/10). For the orbital region, 6/10 favoured magnets. Non-osseointegrated mechanical or adhesive retention techniques are the least expensive and have no contraindications. When osseointegrated implants are possible, each facial region has a favoured system. The choice of system is influenced by two factors: standard practice and the abilities of the maxillofacial surgeon and maxillofacial prosthetist.

Craniofacial implants at a single centre 2005-2015: retrospective review of 451 implants.

Craniofacial endosseous implants are regularly used to support prostheses in the rehabilitation of complex defects, but reported success rates vary. To review our own clinical practice over 10 years, and particularly to examine the impact of radiotherapy and the timing of placement on the survival of implants, we retrospectively audited the records for all patients who had endosseous implants for prosthetic rehabilitation in our unit between 2005 and 2015. We reviewed 167 records, which gave 451 implants, of which, 222 (49%) were auricular, 98 (22%) nasal, and 131 (29%) orbital. Most were placed after ablative operations for cutaneous malignancy (n=103 patients, 62%). The failure rate of implants placed in bone that was irradiated either before or after placement was significantly higher than that of those placed in non-irradiated bone (univariate analysis: 11% compared with 2%, p<0.001: Kaplan-Meier survival analysis: p<0.001). The timing of placement in relation to radiotherapy (before compared with after) seemed to have no impact on success (p=0.96). Our findings are in keeping with previous reports, and the principal observation is that radiotherapy adversely affects success. We work closely with our maxillofacial prosthetists and place implants at the time of ablation. Our findings seem to support this practice regardless of whether or not the patient will later require adjuvant radiotherapy.

3D-Printing Technologies for Craniofacial Rehabilitation, Reconstruction, and Regeneration.

The treatment of craniofacial defects can present many challenges due to the variety of tissue-specific requirements and the complexity of anatomical structures in that region. 3D-printing technologies provide clinicians, engineers and scientists with the ability to create patient-specific solutions for craniofacial defects. Currently, there are three key strategies that utilize these technologies to restore both appearance and function to patients: rehabilitation, reconstruction and regeneration. In rehabilitation, 3D-printing can be used to create prostheses to replace or cover damaged tissues. Reconstruction, through plastic surgery, can also leverage 3D-printing technologies to create custom cutting guides, fixation devices, practice models and implanted medical devices to improve patient outcomes. Regeneration of tissue attempts to replace defects with biological materials. 3D-printing can be used to create either scaffolds or living, cellular constructs to signal tissue-forming cells to regenerate defect regions. By integrating these three approaches, 3D-printing technologies afford the opportunity to develop personalized treatment plans and design-driven manufacturing solutions to improve aesthetic and functional outcomes for patients with craniofacial defects.

Dimensional evaluation of patient-specific 3D printing using calcium phosphate cement for craniofacial bone reconstruction.

The 3D printing process is highlighted nowadays as a possibility to generate individual parts with complex geometries. Moreover, the development of 3D printing hardware, software and parameters permits the manufacture of parts that can be not only used as prototypes, but are also made from materials that are suitable for implantation. In this way, this study investigates the process involved in the production of patient-specific craniofacial implants using calcium phosphate cement, and its dimensional accuracy. The implants were previously generated in a computer-aided design environment based on the patient's tomographic data. The fabrication of the implants was carried out in a commercial 3D powder printing system using alfa-tricalcium phosphate powder and an aqueous solution of Na2HPO4 as a binder. The fit of the 3D printed implants was measured by three-dimensional laser scanning and by checking the right adjustment to the patient's anatomical biomodel. The printed parts presented a good degree of fitting and accuracy.