Novel Deproteinized Natural Rubber Latex Adhesive Used in Extraoral Maxillofacial Prostheses

This study aimed to develop an adhesive for silicone maxillofacial prostheses and compared the properties with the Daro adhesive hydrobond (Factor II, Inc, Lakeside, AZ, USA). Two adhesives were developed from non-vulcanized natural rubber-based adhesives (Adhesive A) and deproteinized natural rubber latex (DNRL) products (Adhesive B) and stored at 4 °C. The Control group was the commercial Daro adhesive hydrobond (Factor II, Inc, Lakeside, AZ, USA). The physical properties (appearance, viscosity, spreadability, color, and pH) of the adhesives were measured and every week for 12 weeks after storing at 4 °C. The adhesives were characterized under scanning electron microscopy. Mechanical testing done were peel bond strength and biocompatibility testing was done using MTT assay. Physical, surface, and mechanical properties were compared with the commercial adhesive. Data analysis was done using SPSS version 24. Both adhesives were physically and chemically stable at temperature 4 °C and had suitable peel bond strength adhesives as the commercial adhesive. Hence, the adhesives can be used to adhere to the maxillofacial silicone prostheses.

Affinity of Staphylococcus aureus for prostheses colonization compared to other bacteria. An in vitro study

Staphylococcus aureus biofilms have been recognized as a leading cause of multiple infections, including implant-associated infections and chronic wounds. We evaluated the colonization capacity of two distinct textured prostheses by different bacterial strains. Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Proteus mirabilis and Enterococcus faecalis were evaluated. Initially, the hydrophobicity and biofilm formation capacity were determined. Subsequently, 20 fragments of vascular prosthesis and 20 silicone prostheses were embedded in suspensions with the microorganisms and incubated. The prostheses were then sown in culture medium and incubated for 48 hours. Petri dishes were photographed and analyzed by fractal dimension. The Kruskal-Wallis test and the Dunn test were applied for the analysis of biofilm formation. To compare the mean intensity for the type of bacteria and the type of prosthesis, a general linear model was applied. Staphylococcus aureus was the bacterium with the highest colonization density in both prostheses (p = 0.0001). E. coli showed strong adherence in the biofilm formation capacity test (p = 0.0001), however, it did not colonize either prosthesis. We demonstrated that Staphylococcus aureus has a greater affinity for vascular and silicone prostheses than other bacteria.

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.

The choise of an extraoral implant with a total facial defect

Subject. Despite upgrading of methods of surgical recovery of total face defects it’s hard to achieve esthetic results. Thanks to implementation of extra-oral implants and production of individual silicone prostheses of external ear, orbit, nose and their compilations it became possible to achieve high esthetic results and firm prosthesis fixation. In the article there is an algorithm showing the choices of extra-oral implants at total face defects keeping in mind the origin of the defect (innate, acquired posttraumatic, postresection) local beam-therapy, which is carried out during the illness and the expected lifetime of the patient. The goal of the research is working out an algorithm of application various implants for innate or acquired total face defects. Methodology. The experience of various extra-oral implants that were used for 50 patients with total defects of external ear, orbit, nose and compilation of those defects was analyzed. Results. The analysis showed that with beamed orbit (total radiation dose higher than 46gr) the implant’s success was 92.5%(25 implants). 2 times implants did not receive osseointegration and during the step of placing the healing cap were removed. With patients with the defect of external ear the frequency of successful osseointegration was 96.2%. 2 times due to cicatricial deformity of skin and periosteal coverage in the zone of defect acquired during thermic burn implants were not integrated. 1 time during the application of covered osseofixated magnet implant in orbit of a 10 year old child a decubital gangrene was formed. Conclusions. Application of extra-oral implants of various types for total face defects proved to its clinical efficiency by differentiated approach considering individual anatomical conditions, cause of the defect and the expected lifetime of the patient.

Effect of different types of disinfection solution and aging on the hardness and colour stability of maxillofacial silicone elastomers

Introduction: Understanding the effect of aging and different disinfecting agents on the physical properties of pigmented maxillofacial silicones may help eliminate the current uncertainty as to the best follow-up suggestions for the patients treated with silicone prostheses. Methods: One hundred fifty specimens (14 × 2 mm) were evaluated for colour and 75 specimens (30 × 10 mm) for hardness (total, 225 specimens). Five specimens were used for hardness testing in each disinfecting solution while 10 silicone specimens were used for colour evaluation. The samples were separated into 5 groups and the initial hardness and colour evaluations were performed and placed in disinfectant solution (neutral soap, effervescent tablet, 0.2% chlorhexidine, 4% chlorhexidine, sodium hypochlorite). A second set of colour and hardness measurements was taken after 48 hours of disinfection and 1,008 hours of artificial aging in a QUV-accelerated weathering tester. Two-way and 1-way analysis of variance with Tukey tests and paired t-test were used for statistical analysis (α = 0.05). Results: Before artificial aging, the hardness value of the red pigment group was found to be significantly lower than that of the brown pigment group. After aging, the lowest Shore A value was seen in the neutral soap group, while the highest was seen in the effervescent tablet. Conclusions: Based on the results of this study, chlorohexidine 0.2% was found to be most suitable agent for disinfection of the prostheses. Washing with neutral soap caused loss of pigment from the surface of the silicones. Sodium hypochlorite was found to have a colour-fading effect on silicone specimens.

An engineering-based approach for design and fabrication of a customized nasal prosthesis

Background and aim: Facial defects (from neoplasms, trauma, etc.) can be functionally and emotionally devastating. A non-invasive treatment for these defects is the application of external prostheses. Conventionally, these prostheses are fabricated by an anaplastologist through a manual procedure, which is an expensive and time-consuming approach. Current advances in computational and engineering tools report an improvement in design and manufacturing of silicone prostheses. This demand motivated this study that aims to develop a methodology for fabricating customized nasal prostheses. Technique: In this study, an 80-year-old woman with a total defect of the nose is considered as case-study. The proposed methodology entails six tasks: (a) data acquisition, (b) three-dimensional reconstruction, (c) prosthesis design, (d) moulds fabrication, (e) prosthesis manufacturing and (f) final fittings. Discussion: The presented approach showed encouraging outcomes since it saves time, reduces costs and allows the achievement of prosthesis with the minimum contact and discomfort to the patient, disclosing excellent aesthetic and functional results. Clinical relevance Custom-made nasal prostheses with minimum contact and discomfort for the patient can be achieved using an engineering approach based on digital technologies and additive manufacturing that is cost-effective and less time-consuming than the manual procedure.