Retention systems used in maxillofacial prostheses: A review.

Defects in the face area caused by trauma, accident, tumor or congenital defects are treated with special facial prostheses. Besides esthetics, the most common problem with these prostheses is the retention of prostheses. In the present article review, the methods used for the retention of prostheses from past to present were researched, and the advantages of adhesives and implants, which are the most commonly used current methods, were evaluated. Current techniques, new materials, treatment options, and implementation procedures are described. The success of maxillofacial prostheses in meeting the expectations of patients and dentist doctors is increasing day by day with the development of adhesive material science, the emergence of technical knowledge, and the development of implant technology. Increasing the retention provides both ease of use and acceptance by the patient. Therefore, the chosen method for retention has great importance in the long-term prognosis of the prosthesis.

Dual-mobility cups in revision acetabular reconstructions: Short-term outcomes in high-risk patients for instability.

OBJECTIVE: The aim of this study was to evaluate the performance of dual-mobility (DM) cup systems for revision total hip arthroplasty (rTHA) in patients who had high risk for instability. METHODS: We prospectively followed up 34 hips of 30 patients (27 females, 3 males; mean age: 66.1 (range: 33 to 89) years) who underwent rTHA with DM cups for aseptic loosening in 23 hips, infection treatment as second or single stage in nine hips, and instability in two hips. Clinical functions of the patients were evaluated using the Harris Hip Score (HHS), and radiological migration or loosening of the DM cups were recorded. The survival of the components was calculated with the Kaplan-Meier survival analysis and failure was defined as any dislocation of the polyethylene (PE) insert, intraprosthetic dislocation (IPD), aseptic loosening of any component or total hip system revision due to any reason. RESULTS: The mean duration of follow-up was 3.52 (range: 2.05 to 6.26) years. There was one dislocation of PE insert (2.9%), which was treated with closed reduction. There were two (5.8%) re-revisions for cemented DM cup due to migration. There was one PE insert and head change due to subacute infection. The mean HHS increased from 42.8 ± 6.7 (range: 34 to 60) points preoperatively to 87.3 ± 5.8 (range: 75 to 98) points postoperatively. The cumulative survival rate of the DM cup system was 91.2% (95% CI: 81.6-100%) with any revision, 94.1% (95% CI: 86.2-100%) with aseptic loosening and %97.1 (%95 CI: 91.4-100%) with dislocation as the end point at 3.5 years. CONCLUSION: Dual-mobility cups may provide good stability and represent a good option for revision acetabular reconstruction in patients who have high risk for instability. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Feasibility and safety of duodenal covered self-expandable metallic stent fixation: an experimental study.

BACKGROUND AND AIMS: Migration of duodenal covered self-expandable metallic stents (C-SEMS) is the main cause of stent dysfunction in patients with malignant gastric outlet obstruction. However, the ideal method to prevent migration has not been clarified. We aimed to evaluate the feasibility and safety of duodenal C-SEMS fixation in this experimental study. METHODS: We used the over-the-scope clip (OTSC), suture, and clip methods to fix duodenal C-SEMS and evaluated the gripping force of each device and invasion depth based on pathological findings. RESULTS: The OTSC and suturing systems had a significantly higher mean gripping force compared with the clipping system (OTSC vs. clip: 13.2 vs. 1.0 Newtons [N], P < 0.001; suture vs. clip: 8.5 vs. 1.0 N, P < 0.001). OTSC compression was stronger compared with suturing (OTSC vs. suture: 13.2 vs. 8.5 N, P = 0.006). The submucosal layer, but not the muscle layer, was compressed more widely and deeply by OTSC compared with clips based on pathological findings by hematoxylin and eosin staining. CONCLUSION: Both OTSC and suturing methods used for duodenal C-SEMS fixation were feasible compared with the clipping method. The pathological evaluation of invasion depth indicated that OTSC may be safe even for preventive use. This study suggested that these methods can be applied clinically for duodenal C-SEMS fixation.

High Correlation Between Achieved and Expected Distraction Using Magnetically Controlled Growth Rods (MCGR) With Rib to Pelvis Fixation in Pediatric Spine Deformity.

PURPOSE: Magnetically controlled implant systems have been established to treat severe progressive spinal deformity in children. The purpose of this study was to evaluate (1) the ratio between achieved and expected distraction length, (2) the complication rate and its risk factors as well as (3) the correlation of the distraction length and the length of the spine. METHODS: A total of 40 patients with an average follow-up of 34 (14 to 57) months were prospectively included in the study. Children underwent lengthening procedures every three months. The ratio between the distraction lengths was determined by comparing the measured distraction length of the rod on radiographs with the distraction length displayed on the external remote controller for the magnetically controlled growing rod (MCGR). Age, weight, height, and complications were repeatedly recorded. RESULTS: The analysis of 746 procedures showed the actual distraction to be 94.4% of the expected one. No difference between implants on the concave and convex spinal side was observed. The overall complication rate was 4.6% mainly because of failure of the implant or lack of implant extension, which was directly related to an increased BMI. There was also a strong correlation between achieved implant distraction length and gain in spinal length. CONCLUSIONS: Our study demonstrates a high ratio (0.94) between achieved and expected distraction length of magnetically controlled spinal rods. The complication rate was low (4.6%) and correlated to a high BMI. The correlation between the achieved implant distraction length and spinal length indicates the efficiency of the MCGR therapy. LEVEL OF EVIDENCE: Therapeutic Level IV.

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.

Magnet-Retained Orbital Prosthesis Using a Dental Implant.

The loss of an eye and the associated facial disharmony has major physical, psychological, and social consequences for patients undergoing orbital exenteration. A magnet-retained prosthesis with an implant has various advantages over both adhesive and spectacle-retained prostheses for reconstruction of the exenterated orbit.The author demonstrates one representative patient with our orbital reconstruction patients with magnetic implants, which will be applied to various maxillofacial prosthesis strategies in the near future.

A systematic comparison of bar-clips versus magnets.

STATEMENT OF PROBLEM: Currently, which type of suprastructure is preferred when fabricating implant-retained craniofacial prostheses is unknown. PURPOSE: The purpose of this systematic review was to identify the best retention system (bar-clips versus magnets) for implant-retained craniofacial prostheses. MATERIAL AND METHODS: This systematic review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A systematic search of Medline/PubMed and Web of Science databases for clinical trials was conducted on implant-retained craniofacial prostheses published between 2005 and 2015. English-language studies that directly compared different types of retention systems or presented information on implant survival, periimplant soft tissue reactions, and prosthetic complications were included. Nonclinical studies were excluded to eliminate bias. RESULTS: A total to 173 studies were identified, of which 10 satisfied the inclusion criteria. In total, 492 participants were included in these studies. Four selected studies displayed detailed information with regard to the number of implant failures according to the retention system. As reported, 29 (18.2%) of 159 implants with magnets failed, whereas 25 (31.6%) of 79 implants with bars failed. Overall auricular superstructures showed the highest survival (99.08%). In addition, 55.4% of all participants in the selected studies showed grade 0 of periimplant soft tissue reactions. CONCLUSIONS: A systematic search for clinical studies resulted in few studies with a short-term follow-up and small number of participants. The limited data collected indicated that magnets show fewer complications than bar superstructures; however, no hard conclusions could be drawn. Further research, preferably in the form of clinical trials, is needed to validate these findings.

Radiologic detectability of the cochlear implant electrode fixation clip using cone beam computed tomography.

INTRODUCTION: With the aim of preventing migration of cochlear implantation electrodes in the postoperative course, an electrode fixation clip has been developed. It is characterized by two clips of double U-geometry. The bone fixation clip will be clamped on the bony incus bridge, and the electrode fixation clip is clamped to the electrode lead. Although made of titanium, the detectability in radiologic imaging appears limited. MATERIALS AND METHODS: Six patients, who received a cochlear implant between August 2014 and March 2015, were retrospectively analyzed for the detectability of the Med-El Electrode Fixation Clip in postoperative cone beam CT scans. For these patients, we randomly extracted appropriate control group patients without implanted clips (matched pairs). One instructed neuro-radiologist blindly evaluated postoperative radiographs on a visual, descriptive basis of both groups with the main outcome measure of clip detectability. RESULTS: In total, images of 12 patients were evaluated. In five of the six (83%) study group patients, the clip was detected radiologically correct. One patient (17%) was appointed as false negative. All patients (100%) without a clip were correctly identified. DISCUSSION: The electrode fixation clip can be identified, despite its small size, using cone beam CT. Sensitivity and specificity are high. This aspect assumes importance especially in postoperative monitoring, e.g. in cases of revision surgery. Thus, this study contributes to the overall safety in cochlear implant surgery.

Prosthetic Rehabilitation of a Complex Maxillofacial Defect as an Alternative to Surgical Reconstruction: A Case History Report.

Free tissue transfers are used to restore maxillofacial resected tissues during tumor ablative surgery. The maxillofacial prosthodontist remains an integral member of the therapeutic team, since conventional retained facial prostheses are in certain cases the most practical, trouble-free, cost-efficient, and successful means of rehabilitation.

Mixing of components from different manufacturers in total hip arthroplasty: prevalence and comparative outcomes.

BACKGROUND AND PURPOSE: There have recently been highly publicized examples of suboptimal outcomes with some newer implant designs used for total hip replacement. This has led to calls for tighter regulation. However, surgeons do not always adhere to the regulations already in place and often use implants from different manufacturers together to replace a hip, which is against the recommendations of the Medicines and Healthcare Products Regulatory Agency (MHRA) and the directions of the manufacturers. PATIENTS AND METHODS: We used data from the National Joint Registry of England and Wales (NJR) to investigate this practice. RESULTS: Mixing of components was common, and we identified over 90,000 cases recorded between 2003 and 2013. In the majority of these cases (48,156), stems and heads from one manufacturer were mixed with polyethylene cemented cups from another manufacturer. When using a cemented stem and a polyethylene cup, mixing of stems from one manufacturer with cups from another was associated with a lower revision rate. At 8 years, the cumulative percentage of revisions was 1.9% (95% CI: 1.7-2.1) in the mixed group as compared to 2.4% (2.3-2.5) in the matched group (p = 0.001). Mixing of heads from one manufacturer with stems from another was associated with a higher revision rate (p < 0.001). In hip replacements with ceramic-on-ceramic or metal-on-metal bearings, mixing of stems, heads, and cups from different manufacturers was associated with similar revision rates (p > 0.05). INTERPRETATION: Mixing of components from different manufacturers is a common practice, despite the fact that it goes against regulatory guidance. However, it is not associated with increased revision rates unless heads and stems from different manufacturers are used together.

Anaplastology in times of facial transplantation: Still a reasonable treatment option?

Optimum functional and aesthetic facial reconstruction is still a challenge in patients who suffer from inborn or acquired facial deformity. It is known that functional and aesthetic impairment can result in significant psychosocial strain, leading to the social isolation of patients who are affected by major facial deformities. Microvascular techniques and increasing experience in facial transplantation certainly contribute to better restorative outcomes. However, these technologies also have some drawbacks, limitations and unsolved problems. Extensive facial defects which include several aesthetic units and dentition can be restored by combining dental prostheses and anaplastology, thus providing an adequate functional and aesthetic outcome in selected patients without the drawbacks of major surgical procedures. Referring to some representative patient cases, it is shown how extreme facial disfigurement after oncological surgery can be palliated by combining intraoral dentures with extraoral facial prostheses using individualized treatment and without the need for major reconstructive surgery.

The current state of facial prosthetics ­ A multicenter analysis.

Even though modern surgical techniques are dominating reconstructive facial procedures, the capability to use facial epitheses for reconstruction is still an important skill for the maxillofacial surgeon. We present an international multicenter analysis to clarify which techniques are used to fixate facial prostheses. We contacted all maxillofacial departments in Germany, Austria, Switzerland and Norway which were registered with the German society for oral and maxillofacial surgery (DGMKG). These centers were asked via electronical mail to provide information on the type of epithesis fixation systems currently in use. The return rate from 58 departments was 43.1% (n = 25). Overall, implant fixation was the preferred fixation system (92%). Plates were the second most common fixation technique (32%). No centers reported the standard use of non-invasive fixation techniques for permanent epithesis fixation. The main retention systems in use were magnets (24/25), other retention systems are used much less often. The current preferred fixation technique for facial epitheses consists of implant-based, magnet-fixated epitheses. For nasal prostheses, a plate-based, magnet-fixated system is often used.

Prosthetic rehabilitation of an extensive midfacial and palatal postsurgical defect with an implant-supported cross arch framework: a clinical report.

When aggressive cancer is surgically treated, the extent of the lesion dictates the amount of tissue excised. The removal of extensive amounts of tissue, including crucial landmarks, complicates prosthesis design. This clinical report details the rehabilitation of a patient who had a total maxillectomy coupled with extensive surgical removal of the midface. With the aid of computer-generated implant placement, a large computer-aided design and computer-aided manufacturing milled titanium framework, a Hader bar, and magnetic keepers, a successful implant retained definitive obturator and facial prosthesis were fabricated that satisfied both esthetic and functional needs.

A surface roughening technique for maxillofacial prostheses.

Giving a natural surface texture to the maxillofacial prostheses is one of the major goals for the maxillofacial prosthodontists. This article describes a technique for application of an antiskid epoxy resin to the surface of the definitive mold before pouring the maxillofacial silicone elastomer. This technique produces evenly distributed and same-size pores that are more similar to the natural appearance of human skin.

Fabrication of a new silicone auricular prosthesis without removing the existing metallic framework.

Silicone prostheses require constant repair and refabrication. Auricular prostheses retained with implants have better retention than adhesive-retained prostheses. However, refabrication is complicated if the patient is unwilling to surrender the metallic framework attached to the implants and revert to the use of adhesives. This article describes a technique by which the metal framework of the existing prosthesis need not be removed, thereby improving the patient's quality of life until the new prosthesis is delivered.

Prosthetic reconstruction of a patient with an acquired nasal defect using extraoral implants and a CAD/CAM copy-milled bar.

Traditionally, patients with maxillofacial defects have been challenging to treat. A multitude of challenges associated with maxillofacial prosthetic treatment are not typically seen with patients who need conventional prosthodontic treatment. These types of patients generally require replacement of significant amounts of hard and soft tissues than do conventional prosthodontic patients. Most maxillofacial patients also warrant more emotional support than do conventional prosthodontic patients. Successful maxillofacial prosthetics still need to embrace the traditional goals of prosthodontic treatment: stability, support, retention, and esthetics. It is unlikely that a maxillofacial prosthesis will exactly duplicate the anatomy and function of missing or damaged structures. Although craniofacial implants (CFI's) have lower cumulative survival rates (CSR's) than intraoral endosseous implants, osseointegrated CFI's have proven to be significant adjuncts to improving retention of maxillofacial prostheses. However, CSR's of CFI's have been reported to be lower than CSR's for intraoral endosseous implants. Lately, computer-assisted design and computer-assisted machining (CAD/CAM) has been used in dentistry to facilitate fabrication of implant-supported frameworks. CAD/CAM protocols have numerous advantages over conventional casting techniques, including improved accuracy and biocompatibility, and decreased costs. The purpose of this paper is to review the literature on cumulative survival rates (CSR's) reported for CFI's and to illustrate the treatment of a maxillofacial patient using CFI's and a CAD/CAM copy-milled framework for retention and support of a nasal prosthesis.

Intraoral-extraoral combination prosthesis: improving retention using interconnecting magnets.

Osseointegrated implants have been well documented for retaining an obturator prosthesis as well as a facial prosthesis. However, when the defect extends to both the facial area and the maxilla, it is difficult to rehabilitate those defects to the satisfaction of the patient, especially in cases where implants cannot be placed on both sites. This case report describes the use of magnets to connect two prostheses, thereby increasing retention and patient comfort.

The use of a laser-level paralleling device for the fabrication of a unilateral auricular prosthesis.

This article describes the use of a laser-level paralleling device for the fabrication of a unilateral auricular prosthesis. Traditional methods require use of calipers to obtain orientation of contralateral auricular anatomy, which in turn can be difficult to replicate on the patient. The purpose of this clinical report is to describe a simple means to record unilateral auricular anatomy.

Complete integration of technology for improved reproduction of auricular prostheses.

The accurate reproduction of the form and surface details of missing body structures is an essential part of any successful prosthetic rehabilitation. It helps mask the prosthesis and gives confidence to the patient. This clinical report details the integration of multiple in-house digital technologies of laser scanning, rapid prototyping, and digital color scanning and formulating to improve the shape, texture, orientation, and color of auricular prostheses for 3 patients with missing unilateral ears. A structured light laser scanner was used to digitize the patient's nondefect ear. The digitized data were then manipulated in specialist software and mirrored to reflect the opposing side. A rapid prototyping machine was used to manufacture a 3-dimensional (3D) model of the soft tissue required. This 3D mirrored ear model allowed the accurate reproduction of missing soft tissue. A color spectrometer was used to accurately reproduce the skin tones digitally and physically.

A unique method of retaining orbital prosthesis with attachment systems - a clinical report.

Diminution of the orbital contents post-surgical removal of a malignant tumor can have a severe psychological impact on the patient in terms of function and esthetics. Therefore, esthetic remedy should be planned subsequently, since tumor obliteration precedes cosmetic concern. A convenient option for successful rehabilitation in such patients is a simple, user-friendly, removable orbital prosthesis. Retention of the prosthesis is one of the key factors for the successful rehabilitation. Spectacle frame, conformers, adhesives, osseointegrated implants, magnets or buttons have been used to impart retention to the prosthesis. The use of semi precision attachments in maxillofacial prostheses is limited to the osseointegrated prostheses. This case report describes a conventional spectacle frame technique, to retain the silicone orbital prosthesis using two different types of stud attachments viz., dalla bona and O-ring attachment systems.