Mechanical properties of tissue adhesives used for retaining extraoral silicone prostheses in maxillofacial defects: A systematic review.

STATEMENT OF PROBLEM: Different tissue adhesives are available for retaining extraoral silicone prostheses in maxillofacial defects. Comparative assessment of their mechanical properties will help the clinician select the right product for a specific clinical situation, but a systematic review is lacking. PURPOSE: The purpose of this systematic review was to analyze the existing data in the literature regarding 5 mechanical properties of tissue adhesives for extraoral silicone prostheses: peel strength, tensile strength, shear strength, torsional strength, and tack. MATERIAL AND METHODS: A manual and electronic search was performed in appropriate databases to identify relevant publications with specific inclusion and exclusion criteria. The retrieved studies were screened for eligibility using the title, abstract, and published full texts. To evaluate the risk of bias, a methodological quality assessment was performed using the Joanna Briggs Institute Critical Appraisal Checklists for Randomized Controlled Trials. A custom data extraction template was used, and the results pooled using descriptive methods. RESULTS: After screening, 15 articles, 5 in vitro studies, and 10 clinical studies were eligible for data extraction. In vitro studies assessed tack and peel bond strength. In contrast, clinical studies assessed peel strength, tensile strength, shear strength, and torsional strength through direct comparisons and in diverse settings. CONCLUSIONS: The assessed studies showed considerable methodological heterogeneity. When silicone-based tissue adhesives (Secure2 Medical Adhesive; Factor II, Hollister Colostomy Adhesive; Hollister Inc, Dow Corning 355 Medical adhesives; Dow Corning Europe Inc) were compared with water-based adhesives (Pros-Aide Adhesive; ADM Tronics Inc, PSA 1; Cosmedica Ltd, Daro adhesive; Factor II, Epithane-3; Daro Products), the silicone-based adhesives showed a higher peel bond strength (PBS), while double-sided medical adhesive tapes showed lower PBS. A few studies evaluated variations in the PBS as being affected by the addition of stone wool fibers, immersion in water, application of skin protective dressings and adhesive removers, application of multiple layers of adhesive, and usage of urethane liner.

Challenges during implant-assisted prosthetic rehabilitation in fibula reconstructed jaws and its management: a scoping review protocol.

Introduction: Oral cancer is the sixth most prevalent cancer type worldwide. Patients are placed in a crippling predicament due to the functional and psychosocial difficulties brought on by the illness and its treatments. Both surgeons and maxillofacial prosthodontists may encounter challenges with reconstruction and therapy following cancer treatment. Over 20 years, the fibula has remained the mainstay of reconstructions for head and neck cancer. Maxillary and mandibular jaws with fibula reconstructions can use fixed or removable prosthetic rehabilitation solutions. The proposed scoping review aims to ascertain the volume and nature of evidence concerning the difficulties and corrective measures in the prosthetic rehabilitation of fibula-reconstructed head and neck cancer cases. The findings will aid in improving the prosthetic treatment care for the affected population. Materials and Methods: The Joanna Briggs Institute (JBI) scoping review protocol will be followed in developing and reporting the scoping review methodology. Methods to identify the relevant literature will involve the systematic search of databases like PubMed, Scopus, Google Scholar, Cochrane Library, and gray literature sources for pertinent articles on the subject. Only papers published in English literature will be considered for the review, and the data collection period is limited to the past 20 years. The screening process will utilize defined inclusion/exclusion criteria for Title/Abstract and Full-text screening by two independent reviewers in covidence, and a third reviewer will resolve any conflicts. The data extracted will include specific details about the participants, concept, population, study methods, challenges encountered during prosthetic rehabilitation, and their management. Inductive thematic analysis and descriptive statistics will be applied where appropriate. The narrative synthesis of the evidence will be accomplished through data extraction in a tabular format, and the results will be presented as a narrative summary.

Effect of Particle Size of Nano-Oxides on Color Stability and Mechanical Properties of Maxillofacial Silicone Elastomers: An In Vitro Study.

PURPOSE: To evaluate the physical and mechanical properties of maxillofacial silicone elastomers following the incorporation of a specific particle size and concentration of nano-titanium dioxide (TiO2) and nano-zinc oxide (ZnO). MATERIALS AND METHODS: Nano-TiO2 and nano-ZnO of 20-nm and 40-nm particle sizes and in 1% and 2% concentrations were chosen. Silicone elastomer samples were prepared according to the manufacturer's recommendations. The nano-oxides were incorporated via hand spatulation. The samples were subsequently tested for hardness and color stability and were then subjected to aging in an aging chamber for 1,008 hours, following which they were again evaluated for hardness, color stability, and surface roughness. RESULTS: A significant change was noted in the physical and mechanical properties post-aging in all the groups. The samples with nano-TiO2 of 40-nm particle size/2% concentration had the highest hardness, while color stability and surface roughness were higher in samples with nano-TiO2 of 20-nm particle size/1% and 2% concentrations, respectively. CONCLUSION: It can be concluded that 20-nm nano-TiO2 particles best maintain the ideal properties of maxillofacial silicone elastomers and can potentially be used as alternative opacifiers when mixed with A-2186 maxillofacial silicone elastomers.

Evaluation of osseointegration of staged or simultaneously placed dental implants with nanocomposite fibrous scaffolds in rabbit mandibular defect.

Implant-supported dental prosthesis in patients with edentulism or those with reconstructed bone have long survival rate, but the success depends largely on the quality and quantity of the available bone at the recipient site. The usage of autograft is the gold standard treatment for vertical bone augmentation, but it has many limitations. In this study, we have developed a nanocomposite fibrous scaffold [silica coated nanoHA-gelatin reinforced with electrospun poly(L-lactic acid) (PLLA) nanoyarns] and evaluated its efficacy to promote osseointegration in rabbit mandibular defect in comparison to the scaffold without fibers and commercial nanoHA-collagen graft. For this, critical sized bilateral defect (10 mm length, 3 mm depth and 3 mm width) was created in rabbit mandible and dental implantation was done in two manners. In strategy 1, Ti dental implant was placed along with the scaffold and in strategy 2, the scaffold was implanted for 3 months to facilitate new bone formation followed by Ti dental implantation. In strategy 2, the fibrous scaffold could promote new bone formation and osseointegration in rabbit mandibular defect when compared to the scaffolds without fibers and commercial graft, but strategy 1 was not successful. These findings demonstrated that nanocomposite fibrous scaffold is a promising biomaterial to promote new bone formation and osseointegration in mandibular defect.

Comparison of Masticatory and Swallowing Functional Outcomes in Surgically and Prosthetically Rehabilitated Maxillectomy Patients.

PURPOSE: This study compared masticatory and swallowing functional outcomes in maxillectomy patients who underwent surgical and prosthetic rehabilitation or prosthetic rehabilitation only following surgical resection. MATERIALS AND METHODS: This comparative cross-sectional study involved 20 maxillectomy patients and compared their masticatory and swallowing functions following combined surgical and prosthodontic management vs an exclusively prosthodontic approach. Masticatory performance was measured by an originally modified sieve method using hydrocolloid material, and video fluoroscopic examination was employed for swallowing assessments. RESULTS: Masticatory performance was significantly better in the patient group treated with flaps and removable denture prostheses compared to patients treated with obturator prosthesis alone. Swallowing outcomes were comparable in both groups. CONCLUSION: Flap reconstruction followed by an obturator prosthesis seems to be a preferable option when planning for functional rehabilitation in maxillectomy patients. Further research is needed to substantiate the functional outcomes noted in this study.

The effect on the flexural strength, flexural modulus and compressive strength of fibre reinforced acrylic with that of plain unfilled acrylic resin - an in vitro study.

AIM: The aim of this in vitro study was to compare the flexural strength, the flexural modulus and compressive strength of the acrylic polymer reinforced with glass, carbon, polyethylene and Kevlar fibres with that of plain unfilled resin. MATERIALS AND METHODS: A total of 50 specimens were prepared and divided into 10 specimens each under 5 groups namely group 1- control group without any fibres, group 2 - carbon fibres, group 3- glass fibres, group 4 - polyethylene, group 5- Kevlar. Universal testing machine (Tinius olsen, USA) was used for the testing of these specimens. Out of each group, 5 specimens were randomly selected and testing was done for flexural strength using a three point deflection test and three point bending test for compressive strength and the modulus was plotted using a graphical method. Statistical analysis was done using statistical software. RESULTS: The respective mean values for samples in regard to their flexural strength for PMMA plain, PMMA+ glass fibre, PMMA+ carbon, PMMA+ polyethylene and PMMA+ Kevlar were 90.64, 100.79, 102.58, 94.13 and 96.43 respectively. Scheffes post hoc test clearly indicated that only mean flexural strength values of PMMA + Carbon, has the highest mean value. One-way ANOVA revealed a non-significant difference among the groups in regard to their compressive strength. CONCLUSION: The study concludes that carbon fibre reinforced samples has the greatest flexural strength and greatest flexural modulus, however the compressive strength remains unchanged.