Retention systems for extraoral maxillofacial prosthetic implants: a critical review

Estimation of differences and reapplication effect of peel bond strength between silicone-based and water-based adhesives

STATEMENT OF PROBLEM

Retention is essential for maxillofacial prosthesis. Adhesives are commonly used for retention because of their simplicity, availability, and cost-effectiveness. Studies that have estimated the differences in bond strength between the types of adhesives and the impact of reapplication are sparse.

PURPOSE

The purpose of this observational clinical study was to estimate the peel bond strength and reapplication effects of water-based and silicone-based adhesives at 0, 24, and 48 hours.

MATERIAL AND METHODS

A total of 46 participants were enrolled, with 23 participants in each adhesive test group-water-based and silicone-based adhesive. Silicone elastomeric strips were attached to the ventral aspect of the participants' forearm 5 cm away from the radial styloid prominence. The strength of each adhesive group was tested at 0 hours, and its reapplication effects were evaluated at 24 and 48 hours. The peel bond strength was estimated by using a universal testing machine, and the data were recorded in N/m and statistically analyzed by the independent Student t test and Spearman rho correlation coefficient tests (α=.05).

RESULTS

The mean ±standard deviation of peel bond strength at 0 hours for silicone-based adhesive (111.5 ±2.5 N/m) was higher than that for water-based adhesive (99.9 ±3.9 N/m) (P<.001). On reapplication, the silicone-based adhesive had a higher peel bond strength (113.5 ±2.8 N/m) than the water-based adhesive (105.2 ±3.0 N/m) (P<.001). The results were statistically significant between the 2 groups at different time intervals (P=.04).

CONCLUSIONS

The mean peel bond strength of the silicone-based adhesive was higher than that of the water-based adhesive. The reapplication of adhesives improved the bond strength in both the groups.

Polymers in 3D printing of external maxillofacial prostheses and in their retention systems

Maxillofacial defects, arising from trauma, oncological disease or congenital abnormalities, detrimentally affect daily life. Prosthetic repair offers the aesthetic and functional reconstruction with the help of materials mimicking natural tissues. 3D polymer printing enables the design of patient-specific prostheses with high structural complexity, as well as rapid and low-cost fabrication on-demand. However, 3D printing for prosthetics is still in the early stage of development and faces various challenges for widespread use. This is because the most suitable polymers for maxillofacial restoration are soft materials that do not have the required printability, mechanical strength of the printed parts, as well as functionality. This review focuses on the challenges and opportunities of 3D printing techniques for production of polymer maxillofacial prostheses using computer-aided design and modeling software. Review discusses the widely used polymers, as well as their blends and composites, which meet the most important assessment criteria, such as the physicochemical, biological, aesthetic properties and processability in 3D printing. In addition, strategies for improving the polymer properties, such as their printability, mechanical strength, and their ability to print multimaterial and architectural structures are highlighted. The current state of the prosthetic retention system is presented with a focus on actively used polymer adhesives and the recently implemented prosthesis-supporting osseointegrated implants, with an emphasis on their creation from 3D-printed polymers. The successful prosthetics is discussed in terms of the specificity of polymer materials at the restoration site. The approaches and technological prospects are also explored through the examples of the nasal, auricle and ocular prostheses, ranging from prototypes to end-use products.

Fabrication of Implant-Supported Auricular Prosthesis Using Artificial Intelligence

The absence of any organ of the facial region causes an asymmetrical appearance. This asymmetrical appearance can cause social dilemmas for the patient. The maxillofacial technician, the prosthodontist, and the patient must work closely together to fabricate an epithesis. On the implants, a superstructure is first constructed. Most of it is made up of rings and a bar that joins the implants. The firm acrylic resin base of the epithesis is equipped with clips that serve as the epithesis's retention mechanism. The actual epithesis is made of silicone rubber. The epithesis has to be shaped and colored with extreme caution. An appropriate substitute is an auricular prosthesis that is implant-retained. Microtia, deformity, malformation, and loss of the external ear, either partially or completely, can result from a variety of inherited genetic conditions. To evaluate the symmetry of both ears, artificial intelligence (AI) software is used. An Instagram lens Gridset by crystalwavesxx was used to correct and verify the bilateral symmetry of the patient. This case report primarily focuses on the fabrication of implant-supported auricular prostheses using AI.

Interdisciplinary prosthetic rehabilitation following bilateral maxillectomy with total upper lip and unilateral zygoma resection: A clinical report

This clinical report describes the design and fabrication of an implant-retained and soft-tissue-supported obturator prosthesis and a magnetic retained midfacial prosthesis for a patient with a midfacial defect following bilateral total maxillectomy, removal of the left zygoma, and excision of the entire upper lip. The patient underwent multiple head and neck surgeries for 4 separate primary oral cancers, 1 recurrence, and 1 pulmonary metastasis. The definitive obturator prosthesis was retained by 1 zygomatic implant with soft-tissue support and retention. The midfacial prosthesis was attached to the obturator prosthesis with magnets, improving appearance and the recovery of significant aspects of the patient's speech and swallowing. Some improvement in mastication was observed.

Fabrication of orbital prosthesis by two different methods in patients with post-COVID-19 rhino-orbital maxillary mucormycosis: A case series

Neoplasms, congenital disorders, fungal infections, and traumatic injuries are the predominant causes of orbital defects. Various retentive mechanisms such as application of adhesive, utilization of mechanical undercuts, and implant-supported attachments are generally used in the maxillofacial prosthesis. In the orbital region, the result of magnet-retained attachments is favorable compared with other mechanisms. Different advantages of the magnet-retained prosthesis are less manual dexterity needed during insertion or removal and better maintenance of hygiene. The skin-implant interface and thick tissues in the maxillofacial region are the critically important points that should be given importance during the planning and placement of implants. Ideally, implant sites for orbital prosthesis are the lateral, infra-, and supraorbital rims of the orbital region. The following case series describes two different methods to rehabilitate patients with an exenterated eye due to mucormycosis by individually designed implant with magnetic attachment and mechanical undercut-retained orbital prosthesis.

A Contemporary Review of the Role of Facial Prostheses in Complex Facial Reconstruction

BACKGROUND

Maxillofacial prostheses provide effective rehabilitation of complex facial defects as alternatives to surgical reconstruction. Although facial prostheses provide aesthetically pleasing reconstructions, multiple barriers exist that prevent their routine clinical use. The accessibility of facial prostheses is limited by the scarce supply of maxillofacial prosthodontists, significant time commitment and number of clinic appointments required of patients during prosthesis fabrication, short lifespan of prostheses, and limited outcomes data.

METHODS

A literature review was completed using PubMed and Embase databases, with search phrases including face and maxillofacial prostheses. Patient cases are included to illustrate the use of facial prostheses to reconstruct complex facial defects.

RESULTS

The clinical use of facial prostheses requires a multidisciplinary team including a reconstructive surgeon, a maxillofacial prosthodontist, and an anaplastologist, if available, to provide patients with aesthetically appropriate facial prostheses. Developing technology including computer-aided design and three-dimensional printing may improve the availability of facial prostheses by eliminating multiple steps during prosthesis fabrication, ultimately decreasing the time required to fabricate a prosthesis. In addition, enhanced materials may improve prosthesis durability. Long-term outcomes data using validated measures is needed to support the continued use of facial prostheses.

CONCLUSIONS

Facial prostheses can be used to reconstruct complex facial defects, and bone-anchored prostheses are associated with high patient satisfaction. Multiple barriers prevent prostheses from being used for facial reconstruction. New technologies to assist the design and fabrication of prostheses, and cost reduction measures, may allow their use in the appropriately selected patient.

Present and future of extraoral maxillofacial prosthodontics: Cancer rehabilitation

Historically, facial prosthetics have successfully rehabilitated individuals with acquired or congenital anatomical deficiencies of the face. This history includes extensive efforts in research and development to explore best practices in materials, methods, and artisanal techniques. Presently, extraoral maxillofacial rehabilitation is managed by a multiprofessional team that has evolved with a broadened scope of knowledge, skills, and responsibility. This includes the mandatory integration of different professional specialists to cover the bio-psycho-social needs of the patient, systemic health and pathology surveillance, and advanced restorative techniques, which may include 3D technologies. In addition, recent digital workflows allow us to optimize this multidisciplinary integration and reduce the active time of both patients and clinicians, as well as improve the cost-efficiency of the care system, promoting its access to both patients and health systems. This paper discusses factors that affect extraoral maxillofacial rehabilitation's present and future opportunities from teamwork consolidation, techniques utilizing technology, and health systems opportunities.

Patient satisfaction with different types of craniofacial prostheses

STATEMENT OF PROBLEM

A maxillofacial prosthesis represents an effective method of giving maxillofacial defects a positive esthetic appearance with minimal risk. However, studies of complications among prosthesis wearers are lacking.

PURPOSE

The purpose of this cross-sectional study was to determine levels of patient satisfaction with various maxillofacial prostheses and retention types, as measured through a survey questionnaire package.

MATERIAL AND METHODS

Patients treated at the Sunnybrook Health Sciences Center Craniofacial Prosthetics Unit (CPU) since 2015 were included. They had been treated according to a standardized protocol and answered a survey questionnaire package with the following sections: demographics, frequency of prosthesis usage, and the Toronto Outcome Measure for Craniofacial Prosthetics (TOMCP-27) survey addressing patient satisfaction. To be eligible for this study, patients must have been more than 18 years of age, in possession of a maxillofacial prosthesis, and received treatment at the Sunnybrook Health Sciences Center CPU since 2015.

RESULTS

A total of 157 patients were eligible and contacted, of whom 51 agreed to participate in the survey. The study population was overall extremely satisfied with their maxillofacial prostheses. In 77.8% of the TOMCP-27 questions, the largest group of patients chose the answer demonstrating the highest level of satisfaction. Of all prosthesis types surveyed, patients with auricular prostheses reported the greatest rates of satisfaction, with the entire group having selected answers corresponding to the highest levels of overall satisfaction. However, patients with orbital prostheses were more likely to experience varying degrees of dissatisfaction, with 72% of the highest reported levels of dissatisfaction being from this prosthesis group. In addition, patients with osseointegrated implant-retained prostheses reported higher satisfaction levels with other retention methods, with the bar clasp group outperforming the magnetic coupling retention group.

CONCLUSIONS

Patients experienced an excellent overall rate of satisfaction with their maxillofacial prostheses. Future development should focus on the continued development of osseointegrated methods, improved magnetic coupling, and improved prosthesis technology, especially for orbital prostheses.

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 nine years without physiologic complications and only minor prosthodontic complications. This article is protected by copyright. All rights reserved.

Rehabilitation of a Midfacial Defect Using a Two-Piece Maxillofacial Prosthesis: A Case Report

Maxillofacial defects and their rehabilitation are a major concern in this socially productive era. The rehabilitation of these massive defects in the oral and maxillofacial region poses a challenge to the prosthodontist in terms of selection of material, retentive aids, the adaptive capability of the patient, and cost. This case report describes the management of the midfacial defect involving the orbit, zygoma, maxilla, and their soft tissue counterparts with a removable silicone extraoral compartment and an acrylic intraoral compartment, which are retained with strong cobalt samarium magnets, an elastic loop around the occiput, and spectacles. The maxillofacial prosthesis fabricated for this patient restored the patient’s facial esthetics, speech, dental articulation, lip support, mastication, and anterior maxillary seal.

Rehabilitation of Auricular Defect with Implant-Retained Auricular Prosthesis - A Case Report

Rationale:

Maxillofacial defect is of great concern physically, emotionally, and psychologically for a patient. However, it is an even bigger challenge for a team attempting rehabilitation, as a crucial decision has to be made between surgical approach and/or prosthetic rehabilitation. However, if both are combined, it will result in best of esthetics and function with ease of maintainance, resulting in a sucessful rehabilitation. This case report represents a case of auricular defect rehabilitated with a combination of implants and bar-retained silicone prosthesis.

Patient Concern:

A 38-year-old male patient with right auricular defect reported with the main concern of esthetic rehabilitation of a lost part of the external ear.

Diagnosis:

With through evaluation and examination, a diagnosis of acquired partial auricular defect of the right side secondary to trauma was established.

Treatment:

An implant-retained auricular prosthesis was planned for this case. Surgically, three intraoral implants were placed in the mastoid bone, and after healing, bar framework was fabricated and attached. Finally, silicone prosthesis was fabricated and delivered to the patient.

Outcome:

A successful rehabilitation was carried out in this case using implants and bar attachment for retention of the silicone prosthesis. This prosthesis provided excellent retention and restored the appearance and confidence of the patient.

Take-away Lessons:

Rehabilitation of the auricular defect can be carried out with surgical approach, which involves multiple surgeries, and still, the results may not be esthetically favorable. Prosthetic rehabilitation is an option, but retention is generally a hindrance. However, implant-retained prosthesis has really paved a way for rehabilitation of the maxillofacial defect esthetically and more reliably. Cone-beam computerized tomography (CT) can be used for planning and evaluation instead of CT, which will save the patient from a lot of radiation exposure. Hence, in the maxillofacial defect, attempts should be made to explore the option of implant-retained prosthesis.

Two-piece oral facial prothesis retained with magnets for a complex maxillary facial defect: A clinical report

Total flap failure is a devastating complication in head and neck reconstruction. This clinical report describes the rehabilitation of an extensive maxillectomy defect communicating with the midface by using a 2-piece magnet-retained orofacial prosthesis fabricated in heat-processed acrylic resin. The innovative design and choice of material allowed early rehabilitation of a patient receiving palliative care at a resource-constrained tertiary care oncology center. Prosthetic treatment served to reduce the period of hospitalization and helped the patient to resocialize.

An implant-retained auricular prosthesis complicated by a modified temporal bone resection

A patient underwent a modified temporal bone resection and total auriculectomy to remove a sebaceous carcinoma arising from the tragus of the right auricle that extended into the external auditory meatus. Because the tumor extended into the temporal bone, the osseous sites originally selected for immediate placement of the craniofacial implants were resected and no longer available. Subsequently, after an appropriate period of healing, implants were placed into the residual temporal bone, considerably more superior and posterior to the external auditory meatus such that they emerged through hair-bearing skin. The purpose of this report was to describe the fabrication of an implant-retained auricular prosthesis with implants in suboptimal positions. Challenges included optimization of the stability and retention of the prosthesis, effectively managing the prosthetic space without compromising the esthetic outcome, providing adequate hygiene access for the implant connecting bar, and maintaining the health of the peri-implant tissues when the implant emerged through hair-bearing skin.

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.

Implant-Retained Nasal Prosthesis with Bar and Clip for a Patient with Total Rhinectomy: A Clinical Report

The present clinical report describes the fabrication of an implant -retained prosthesis with bar and clip retention for a patient with total rhinectomy due to basal cell carcinoma (BCC). The nasal prosthesis was retained on the face by a reverse Y-shaped bar with horizontal and vertical extensions, resulting in favorable retention and function.

Current concepts and novel techniques in the prosthodontic management of head and neck cancer patients

'The face is the mirror of the mind', so said St Jerome. Patients affected by head and neck cancer have to deal not only with the effects of the disease but also with the effects of the treatment for the disease. This is one cancer which is literally and figuratively 'in your face'! And it is a disease which is difficult to hide. This article attempts to summarise head and neck cancer and its treatment modalities as well as the effects of treatment and the defects it creates. It will also attempt to explore and elaborate on the novel prosthodontic management techniques in advanced jaw reconstruction and extraoral anatomical defects. The concept of functional assessment and rehabilitation in head and neck cancer patient management will also be briefly explained.

Bar-clip versus magnet-retained auricular prostheses: A prospective clinical study with a 3-year follow-up

STATEMENT OF PROBLEM

Implant-retained auricular prostheses, on a bar-clip or with a magnetic retention system, are considered successful treatment for missing ears. However, which of these 2 retention systems is preferred by patients is unknown.

PURPOSE

The purpose of this clinical study was to assess which retention system is mostly preferred by patients wearing implant-retained auricular prostheses: bar-clip retention or magnetic retention.

MATERIAL AND METHODS

All consecutive patients visiting the clinic between March 2014 and November 2014 for a routine follow-up of their implant-retained auricular prostheses on a bar-clip retention system were asked to enroll in this descriptive study comparing patient preference for the retention system: bar-clip versus magnets. Participants were asked to complete a questionnaire to obtain patient satisfaction scores regarding their auricular prosthesis before and 3 months after changing to a magnetic-retained auricular prosthesis. After 3 months, participants were asked to state their preference for either their previous bar-clip system or the new magnetic system. If they did not prefer the magnetic system, participants were able to return to their previous bar-clip system. The study follow-ups were performed at 6, 12, 24, and 36 months. Again, patient satisfaction was scored with the aid of the same questionnaire, and prosthetic care and aftercare were also assessed.

RESULTS

Of 20 eligible patients, 17 participants (12 men, 5 women) enrolled in the study. The mean score for patient satisfaction for the bar-clip system at the start of the study was high (8 ±1.62). After 3 months, 2 participants wanted to return to their previous bar-clip system, followed by 1 more at the 6-month evaluation and 2 more at the 1-year evaluation. After 3 years, 9 of 16 participants (57%) preferred the magnetic-retained auricular prosthesis. During the 3 years of follow-up, aftercare was considered minor for both the bar-clip and the magnetic system. No participants developed peri-implantitis. All participants indicated that cleaning and placing the magnetic-retained auricular prosthesis was easier than the bar-clip system.

CONCLUSIONS

The majority of the participants (59%) in this study, especially the elderly participants, preferred the magnetic retention system. When compared with the bar-clip system, no additional aftercare was needed.

Classification, History, and Future Prospects of Maxillofacial Prosthesis

This review presents a classification system for maxillofacial prostheses, while explaining its types. It also aims to describe their origin and development, currently available materials, and techniques, predicts the future requirements, and subsequently discusses its avenues for improvement as a restorative modality. A literature search of the PubMed/Medline database was performed. Articles that discussed the history, types, materials, fabrication techniques, clinical implications, and future expectations related to maxillofacial prostheses and reconstruction were included. Fifty-nine articles were included in this review. Maxillofacial prostheses were classified as restorative or complementary with subclassifications based on the prostheses finality. The origin of maxillofacial prostheses is unclear; however, fabrication techniques and materials have undergone several changes throughout history. Currently, silicones and acrylic resins are the most commonly used materials to fabricate customized prostheses. Maxillofacial prostheses not only restore several types of orofacial defects but also improve the patients' quality of life. Although the current clinical scenario concerning the field of maxillofacial prostheses is promising, improvements in material quality and techniques for maxillofacial prostheses may be expected in the future, to produce better results in the treatment of patients.

Complex functional and epithetic rehabilitation after ablation of recurrent retroauricular basal cell carcinoma - a case study

The reconstruction of extended defects of the concha poses a complex challenge for plastic surgeons. In cases of subtotal ablation, an alternative method designed especially for elderly oncological patients consists of epithetic rehabilitation. However, inserting an implant-retained concha epithesis proves challenging in patients with antecedents of deep resections involving the mastoid process. In the present case study, we report on the long-term treatment course (2009-2017) of a 79-year-old male patient suffering from a recurrent basal cell carcinoma of the retroauricular region. Following tumor resection, along with lateral mastoidectomy, reconstruction, and adjuvant radiotherapy, functional and esthetic deficits primarily due to peripheral facial nerve palsy were successfully managed using a multistep procedure. The procedure was completed by inserting an implant-retained concha epithesis, resulting in improved quality of life. Due to prior lateral mastoidectomy, ultra-short implants (4 mm) were inserted, partially at atypical positions. For maintaining healthy periimplant soft tissue, aftercare comprised cold plasma treatment. This oncologic case demonstrates the therapeutic necessity of using a broad spectrum of reconstructive procedures, along with their limitations, in a critical anatomic region. Specific features include the presentation of a workflow using ultra-short implants in a compromised mastoid region. Surgeons should consider alternative implant positions in the event of any compromised mastoid process. A particular emphasis has been put on meticulous aftercare to preserve healthy periimplant soft tissues.

Osseointegrated Implants and Prosthetic Reconstruction Following Skull Base Surgery

Rehabilitation following ablative skull base surgery remains a challenging task, given the complexity of the anatomical region, despite the recent advances in reconstructive surgery. Remnant defects following resection of skull base tumors are often not amenable to primary closure. As such, numerous techniques have been described for reconstruction, including local rotational muscle flaps, pedicled flaps with skin paddle, or even free tissue transfer. However, not all patients are appropriate surgical candidates and therefore may instead benefit from nonsurgical options for functional and aesthetic restoration. Osseointegrated implants and biocompatible prostheses provide a viable alternative for such a patient population. The purpose of this review serves to highlight current options for prosthetic rehabilitation of skull base defects and describe their indications, advantages, and disadvantages.