The current state of facial prosthetics – A multicenter analysis

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.

Perception of orbital epitheses evaluated with eye tracker

PURPOSE

Orbital epitheses replace a missing eyeball and surrounding soft tissue. Perception of epithesis in public gaze and the attention areas on the face are of interest. This study aimed to examine the differences in perception of orbital epitheses by prosthodontists, dentistry students, and laypeople with an objective evaluation tool that utilized eye-tracking technology.

MATERIALS AND METHODS

Twenty-four frontal facial images of 12 patients who had orbital epitheses were viewed by 81 observers (prosthodontists, dentistry students, laypeople) in random order for 5 seconds each. Gaze data were analyzed. Kruskal-Wallis H test with Bonferroni correction was used to compare parameters in groups and areas of interest.

RESULTS

First fixation duration at the mouth for symmetrical images were 0.30, 0.28, and 0.25 seconds for prosthodontists, students, and laypeople, respectively. Fixation duration at the mouth for the laypeople (0.27 second) was shorter than students (0.29 second) and prosthodontists (0.31 second) at symmetrical images. Time to the first fixation to epithesis, nose, and eye was significantly lower than the forehead and mouth for all groups. Fixation count at epithesis was 6.36 for prosthodontists, 5.64 for students, and 5.34 for laypeople.

CONCLUSION

Eyes were of most significant interest for all observer groups in symmetrical images. Individuals dealing with dentistry, especially prosthodontists, paid more attention to the mouth region along with the eyes in symmetrical images, considering fixation duration and fixation count. Attention directed to epithesis by all groups was verified with objective and measurable criteria. Prosthodontists' attention to epithesis and mouth was evident considering the four parameters measured.

Effect of Superhydrophobic Coating and Nanofiller Loading on Facial Elastomer Physical Properties

Facial prosthetics are currently constructed of materials that are far from optimal; superior materials with a “skin-like” feel are required. In this study, the property changes brought about by the consecutive additions of hydrophobic- and uncoated nano-SiO2 to polydimethylsiloxane (PDMS) are assessed, and the alterations are compared with those observed for conventional submicron SiO2-filled materials. In sequence, 0%, 0.5%, 5%, 10%, and 15% by weight of each filler type were successively added to vinyl-terminated PDMS. Tensile, tear, Durometer hardness, translucency, and viscoelastic properties were assessed, and hardness and translucency were further measured after 3000 h of outdoor weathering. The results showed that 15% coated nano- SiO2-filled PDMS materials given the highest tensile strength, elastic modulus, storage modulus, loss modulus, tear strength, and durometer hardness (p < 0.05), whereas 15% submicron coated SiO2-filled materials displayed the highest failure strain and translucency parameter (p < 0.05). Only 10%- and 15%-filled submicron SiO2 PDMS materials were altered by outdoor weathering; nevertheless, the increases were assessed to be too small to be clinically perceptible. As increased filler levels provided protection against solar radiation, heat, and moisture, only unfilled and 0.5%-filled PDMS formulations discolored from weathering. 15%-filled superhydrophobic-coated nano- SiO2-filled PDMS was found to produce the strongest, most tear-resistant, and least translucent materials, but it also produced materials with limited stretchability and high hardness, which were regarded to be downsides for creating a “skin-like” feel.

Oculofacial Prosthetic Rehabilitation Complemented With Temporary Fillers and Neurotoxin

ABSTRACT

Surgical treatment of head and neck cancer causes severe tissue loss, therefore, deformities and psychosocial consequences. In cases involving orbit exenteration, satisfactory reconstruction can only be achieved with prosthetic replacement, despite successful reconstructive plastic surgery. Extraoral implants, 3D scanning, and prototyping technologies have contributed to increase satisfactory aesthetic results of oculofacial prosthesis. However, to achieve prosthetic rehabilitation refinement, patients' biological tissues have been treated with injectable cosmetic adjuncts methods as complements to results. This study aimed to describe the use of botulinum toxin type A, hyaluronic acid, and calcium hydroxyapatite previously to oculofacial prostheses manufacturing, in 5 oncologic patients of a rehabilitation unit. Outcomes produced by additional cosmetic methods on tissues, prostheses planning, and overall facial rehabilitation were observed and registered by photographs. Botulinum toxin type A, hyaluronic acid, and calcium hydroxyapatite has shown to be useful in improving asymmetries, volumizing surgical depressions and dissembling atrophic scars. Presenting an additional resource to improve overall results, enabling the manufacturing of smaller, thinner, and better-fitting oculofacial prostheses. Limitations as chronic infection and necrosis episodes, related to filler injection into previously irradiated sites, were described. The temporary effect of the materials used generates a need for reapplications but increases the safety of such procedures and enables patients' cancer treatment follow-up.

Accuracy of capturing nasal, orbital, and auricular defects with extra- and intraoral optical scanners and smartphone: An in vitro study

OBJECTIVES

This in vitro study compares the scanning accuracy of various stationary and portable as well as extra- and intraoral devices for capturing oncological defects.

METHODS

A 3D-printed model of a nasal, orbital, and auricular defect, as well as one of an intact auricle, were digitalized (n = 7 per device) with a stationary optical scanner (Pritiface), a portable extraoral optical scanner (Artec Space Spider), two intraoral scanners (Trios 4 and Primescan), and a smartphone (iPhone 11 Pro). For the reference data, the defect models were digitalized using a laboratory scanner (D2000). For quantitative analysis, the root mean square error value for trueness and precision and mean deviations in millimeters were obtained for each defect type. The data were statistically analyzed using two-way ANOVA and Tukey multiple comparison test. For qualitative analysis, a colorimetric map was generated to display the deviation within the defect area and adjacent tissue.

RESULTS

Statistically significant interactions were found in the trueness and precision for defect and scanner type.

CONCLUSION

The Primescan and Artec Space Spider scanners showed the highest accuracy for most defect types. Primescan and Trios 4 failed to capture the orbital defect. The iPhone 11 Pro showed clinically acceptable trueness but inferior precision.

CLINICAL SIGNIFICANCE

The scanning devices may demonstrate varying accuracy, depending on the defect type. A portable extraoral optical scanner is an universal tool for the digitization of oncological defects. Alternatively, an intraoral scanner may be employed in maxillofacial prosthetics with some restrictions. Utilizing a smartphone in maxillofacial rehabilitation should be considered with caution, because it provides inconsistent accuracy.

[Optimized fitting of a midface implant to anchor a magnetic nasal prosthesis using 3D printing]

Hintergrund

Plattenbasierte Ankersysteme zur fazialen Epithesenversorgung bieten gegenüber extraoralen Einzeltitanimplantaten Vorteile hinsichtlich einer flexibleren Wahl knöcherner Verankerungspunkte und höherer Stabilität. Nachteile werden in einer aufwendigen individuellen intraoperativen Anpassung der Plattensysteme am meist schlecht zugänglichen Knochen deutlich. Wir stellen eine Methode vor, diese Nachteile zu überwinden und die Vorteile plattenbasierter Systeme stärker auszuspielen.

Methodik

Das knöcherne Mittegesicht eines Patienten mit erfolgter Rhinektomie bei Karzinom des Naseneingangs wurde anhand der präoperativen Computertomographie als virtuelles 3‑D-Modell rekonstruiert. Die verwendete Open-Source-Software (3-D-Sclicer) ermöglichte die einfache und schnelle Rekonstruktion sowie Anpassung zum Druck des 3‑D-Modells mittels transparenten Kunststoffs (MED610; stratasys Ltd., MN, USA).

Ergebnisse

Die als Epithesenanker verwendete Titan-Brückenplatte (MEDICON) konnte am 3‑D-Druck des Mittelgesichts äußerst präzise vorangepasst werden. Wichtige anatomische Strukturen wurden geschont und die Verschraubungspunkte entsprechend der gegebenen Knochendicke gewählt. Die Implantation der vorangepassten Titanplatte erfolgte komplikationslos ohne weitere intraoperative Anpassungen.

Schlussfolgerung

Die Voranpassung plattenbasierter Ankersysteme für faziale Epithesen am 3‑D-Druck des Mittelgesichts überwindet deren Nachteile einer aufwendigen ggf. unpräzisen intraoperativen individuellen Anpassung. Diese Methode spielt die Vorteile der besseren Kraftverteilung durch mehr mögliche Verschraubungen, auch in dünnerem Knochen, weiter aus und kann somit Implantatlockerungen vorbeugen. Zudem ermöglicht die Voranpassung am 3‑D-Modell die bessere Identifikation und Schonung wichtiger anatomischer Strukturen und spart Op.-Zeit ein.

DENTAL PATIENT-REPORTED OUTCOMES -- THE PROMISE OF DENTAL IMPLANTS

In general dental practice, the use of implants is focused mostly on prosthodontic issues. That is, the replacement of missing teeth or the support of dental prostheses. However, there are other dental fields using implants such as orthodontics or maxillofacial prosthodontics. A classic way to measure success in implant dentistry is to look how long implants and the corresponding superstructure survive and are in function. Nevertheless, this alone is a very crude parameter. Therefore, biological and technical complications are taken in account additionally. Nonetheless, these objective measures do not well replicate the perception of the patient. That why, subjective measures, reflecting the perception of the patient are recommended to complement objective parameters. If these dental patient-reported outcome measures (dPROMs) are wisely chosen, they offer a wide variety of options. Besides comparing therapeutic effects by using the instruments' summary score only, dPROMs such as the Oral Health Impact Profile (OHIP) provide the opportunity to additionally assess patients` perceptions in the 4 dimensions of oral health-related quality of life. These are functional limitations, pain, esthetic issues as well as psychosocial impairment. Even the 5-item short form of the OHIP captures these dimensions and provides an efficient way to assess patients' perception with low administrative burden. This in turn offers new insights into the patient perspective and therefore helps improving shared decision making.

[Prosthetic rehabilitation in the head and neck region]

Implant-retained craniofacial prostheses (or epitheses) made of silicone are state of the art for prosthetic rehabilitation of facial defects. With the modern extraoral implant systems, prostheses may be securely anchored to the bone regardless of size and location of the defect. Prerequisite for successful implantation is the classical atraumatic surgical technique with avoidance of any thermal trauma to the bone. The treatment intention may be a temporary measure, a rescue procedure after failed (re)construction, or a definitive treatment option. This article gives an overview of the strategies in various facial regions stratified according to the age of the patient and the etiology of the defect. Moreover, prosthetic rehabilitation offers additional options for septal perforations, distorted and leaky tracheostomies, and treatment-resistant tracheoesophageal fistula.

Topographic bone thickness maps to evaluate the intuitive placement of titanium miniplates for nasal prostheses

The aim of this study was to evaluate the intuitive placement of titanium miniplates. The hypothesis was that virtual planning can improve miniplate placement. Twenty patients were included in the study. These patients were fitted with 21 titanium miniplates (16 y-plates, three t-plates, and two u-plates) to retain nasal prostheses between 2005 and 2017. Colour-coded topographic bone thickness maps (TBTMs) were created in fused pre- and postoperative computed tomography. Implants were virtually transposed at the position of highest bone thickness. The bone thickness index (BTI) was calculated as the sum of points assigned at each screw (1 point per millimetre up to 4 mm, and 5 points for greater values) divided by the number of screws. One plate broke after 2.8 years, thus plate survival after 5 years was 91% using the Kaplan-Meier method. The BTI for all 21 plates increased from 3.4 to 4.1 points using virtual transposition (P<0.001). No significant changes were observed in t- and u-plates, but the median BTI increased from 3.1 to 4.1 points (P<0.0005) in 16 y-plates. The change was substantial (≥0.5 points) in 9/16 y-plates. Therefore, the hypothesis that virtual planning improves implant placement was accepted.

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.

Place of 3D printing in facial epithesis

Facial rehabilitation from facial epithets is part of the facial surgeon's therapeutic arsenal. The primary technique requires taking imprints on the patient, which has major drawbacks such as discomfort and difficulties for precisely recording anatomical surfaces. In this paper, we present a technical improvement in the design of facial epithesis, introducing application of a 3D printing technology. By exploiting digital data in DICOM format, it is possible to produce a digital copy of an epithesis. Based on this copy a model can be printed and then used to support the final prosthesis.

Fabrication of an Orbital Prosthesis Combined With Eyebrow Transplantation

Fabrication of an orbital prosthesis is considered as a challenging procedure as compared to the other facial prosthesis due to the presence of inactive eye movements and the need of artificial hair in order to mimic eyelashes and eyebrows. Generally these structures are sewed or bonded in the silicone. However, deformation or hair loss is observed within time. This deformation is visible especially in the eyebrow. This clinical report represents a patient with an implant supported orbital prosthesis. Patient was not satisfied with the nature of her eyebrow that was sewed in the silicone. Therefore, an alternative approach of eyebrow transplantation was used for the patient. The patient expressed her better satisfaction of this definitive prosthesis supported with eyebrow transplantation.

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.

Survival and complications of implants to support craniofacial prosthesis: A systematic review

OBJECTIVE

To assess the survival rate of craniofacial implants (CIs) to support facial prosthesis/epithesis and the prevalence of surgical/biological complications based on previously published studies.

METHODS

An electronic search was undertaken in March/2016. Only studies with a minimum of 5 patients were included. Untransformed proportions of implant failures for different regions were calculated. A meta-analysis evaluated the influence of radiotherapy on the failure rates. A meta-regression was performed considering the follow-up period as covariate.

RESULTS

Seventy publications included 2355 patients and 8184 CIs (545 failures). The probability of a failure was 5.5% for all CIs (95%CI 4.5-6.5, P < 0.001), 1.2% for CIs in the auricular region (95%CI 0.8-1.5, P < 0.001), 12.2% for the nasal region (95%CI 9.0-15.5, P = 0.017), and 12.1% for the orbital region (95%CI 9.3-15.0, P < 0.001). Radiotherapy statistically affected the CIs rates (OR 5.80, 95%CI 3.77-8.92, P < 0.00001). There was no statistically significant influence of the follow-up time on the proportion of implant failures (P = 0.814). Soft tissue adverse reactions were the most common complications.

CONCLUSIONS

Implants placed in the auricular region have a lower probability of failure than those in the nasal and orbital regions. Soft tissue adverse reactions were the most common complications. Radiotherapy significantly affected the CIs failure rates.

Monoscopic photogrammetry to obtain 3D models by a mobile device: a method for making facial prostheses

Purpose

The aim of this study is to present the development of a new technique to obtain 3D models using photogrammetry by a mobile device and free software, as a method for making digital facial impressions of patients with maxillofacial defects for the final purpose of 3D printing of facial prostheses.

Methods

With the use of a mobile device, free software and a photo capture protocol, 2D captures of the anatomy of a patient with a facial defect were transformed into a 3D model. The resultant digital models were evaluated for visual and technical integrity. The technical process and resultant models were described and analyzed for technical and clinical usability.

Results

Generating 3D models to make digital face impressions was possible by the use of photogrammetry with photos taken by a mobile device. The facial anatomy of the patient was reproduced by a *.3dp and a *.stl file with no major irregularities. 3D printing was possible.

Conclusions

An alternative method for capturing facial anatomy is possible using a mobile device for the purpose of obtaining and designing 3D models for facial rehabilitation. Further studies must be realized to compare 3D modeling among different techniques and systems.

Clinical implication

Free software and low cost equipment could be a feasible solution to obtain 3D models for making digital face impressions for maxillofacial prostheses, improving access for clinical centers that do not have high cost technology considered as a prior acquisition.