Injectable and biodegradable piezoelectric hydrogel for osteoarthritis treatment.

Osteoarthritis affects millions of people worldwide but current treatments using analgesics or anti-inflammatory drugs only alleviate symptoms of this disease. Here, we present an injectable, biodegradable piezoelectric hydrogel, made of short electrospun poly-L-lactic acid nanofibers embedded inside a collagen matrix, which can be injected into the joints and self-produce localized electrical cues under ultrasound activation to drive cartilage healing. In vitro, data shows that the piezoelectric hydrogel with ultrasound can enhance cell migration and induce stem cells to secrete TGF-ß1, which promotes chondrogenesis. In vivo, the rabbits with osteochondral critical-size defects receiving the ultrasound-activated piezoelectric hydrogel show increased subchondral bone formation, improved hyaline-cartilage structure, and good mechanical properties, close to healthy native cartilage. This piezoelectric hydrogel is not only useful for cartilage healing but also potentially applicable to other tissue regeneration, offering a significant impact on the field of regenerative tissue engineering.

Alveolar Ridge Augmentation with a Novel Combination of 3D-Printed Scaffolds and Adipose-Derived Mesenchymal Stem Cells-A Pilot Study in Pigs.

Alveolar ridge augmentation is an important dental procedure to increase the volume of bone tissue in the alveolar ridge before the installation of a dental implant. To meet the high demand for bone grafts for alveolar ridge augmentation and to overcome the limitations of autogenous bone, allografts, and xenografts, researchers are developing bone grafts from synthetic materials using novel fabrication techniques such as 3D printing. To improve the clinical performance of synthetic bone grafts, stem cells with osteogenic differentiation capability can be loaded into the grafts. In this pilot study, we propose a novel bone graft which combines a 3D-printed polycaprolactone-tricalcium phosphate (PCL-TCP) scaffold with adipose-derived mesenchymal stem cells (AD-MSCs) that can be harvested, processed and implanted within the alveolar ridge augmentation surgery. We evaluated the novel bone graft in a porcine lateral alveolar defect model. Radiographic analysis revealed that the addition of AD-MSCs to the PCL-TCP scaffold improved the bone volume in the defect from 18.6% to 28.7% after 3 months of healing. Histological analysis showed the presence of AD-MSCs in the PCL-TCP scaffold led to better formation of new bone and less likelihood of fibrous encapsulation of the scaffold. Our pilot study demonstrated that the loading of AD-MSCs improved the bone regeneration capability of PCL-TCP scaffolds, and our novel bone graft is suitable for alveolar ridge augmentation.

Clinical Applications of Artificial Intelligence and Machine Learning in Children with Cleft Lip and Palate-A Systematic Review.

OBJECTIVE: The objective of this systematic review was (a) to explore the current clinical applications of AI/ML (Artificial intelligence and Machine learning) techniques in diagnosis and treatment prediction in children with CLP (Cleft lip and palate), (b) to create a qualitative summary of results of the studies retrieved. MATERIALS AND METHODS: An electronic search was carried out using databases such as PubMed, Scopus, and the Web of Science Core Collection. Two reviewers searched the databases separately and concurrently. The initial search was conducted on 6 July 2021. The publishing period was unrestricted; however, the search was limited to articles involving human participants and published in English. Combinations of Medical Subject Headings (MeSH) phrases and free text terms were used as search keywords in each database. The following data was taken from the methods and results sections of the selected papers: The amount of AI training datasets utilized to train the intelligent system, as well as their conditional properties; Unilateral CLP, Bilateral CLP, Unilateral Cleft lip and alveolus, Unilateral cleft lip, Hypernasality, Dental characteristics, and sagittal jaw relationship in children with CLP are among the problems studied. RESULTS: Based on the predefined search strings with accompanying database keywords, a total of 44 articles were found in Scopus, PubMed, and Web of Science search results. After reading the full articles, 12 papers were included for systematic analysis. CONCLUSIONS: Artificial intelligence provides an advanced technology that can be employed in AI-enabled computerized programming software for accurate landmark detection, rapid digital cephalometric analysis, clinical decision-making, and treatment prediction. In children with corrected unilateral cleft lip and palate, ML can help detect cephalometric predictors of future need for orthognathic surgery.

In vitro cytotoxicity and osteogenic potential of quaternary Mg-2Zn-1Ca/X-Mn alloys for craniofacial reconstruction.

Cytotoxicity of any biomedical material needs to be investigated for successful application within the human tissues. In this study, manganese in low amounts of 0.3, 0.5 and 0.7 (wt.%) was added to Mg2Zn1Ca alloy using Disintegrated Melt Deposition (DMD) followed by hot extrusion and the extruded alloys were tested for in vitro cytocompatibility using cell viability assays (CCK-8, LDH enzyme release assay, cell cytoskeleton and cell morphology) and in vitro osteogenic potential was evaluated using ALP, Alizarin Red and RT-PCR assays. Addition of manganese improved the cell viability and osteogenic potential in variable concentrations. The Mg2Zn1Ca /0.3 Mn and Mg2Zn1Ca /0.5 Mn alloys showed increased cell viability percentage compared to Mg2Zn1Ca alloys. The cytotoxicity percentage at the end of 24 h culture for Mg2Zn1Ca /0.3 Mn alloys showed lesser cytotoxicity percentage (~ 8%) when compared to the Mg2Zn1Ca /0.5 Mn (~ 13%) and Mg2Zn1Ca /0.7 Mn (~ 16%) samples. All the alloys showed good initial cell attachment, osteogenic potential and cell spreading. The results of this study validates great potential of Mg2Zn1Ca alloys with manganese addition and exhibited great potential for to be used as temporary implant materials in craniofacial reconstruction.

Compositional Tailoring of Mg-2Zn-1Ca Alloy Using Manganese to Enhance Compression Response and In-Vitro Degradation.

The present study investigates Mg-2Zn-1Ca/XMn alloys as biodegradable implants for orthopedic fracture fixation applications. The effect of the presence and progressive addition of manganese (X = 0.3, 0.5, and 0.7 wt.%) on the degradation, and post-corrosion compressive response were investigated. Results suggest that the addition of manganese at 0.5 wt.% improved the corrosion resistance of Mg-2Zn-1Ca alloys. The pH values stabilized for the 0.5Mn-containing alloy and displayed a lower corrosion rate when compared to other Mg-2Zn-1Ca/Mn alloys. Mg-2Zn-1Ca showed a progressive reduction in the compressive strength properties at the end of day 21 whereas Mg-2Zn-1Ca/0.3Mn and Mg-2Zn-1Ca/0.5Mn samples showed a decrease until day 14 and stabilized around the same strength range after day 21. The ability of Mg-2Zn-1Ca/0.5Mn alloy to develop a network of protective hydroxide and phosphate layers has resulted in the corrosion control of the alloy. Mg-2Zn-1Ca/0.7Mn displays segregation of Mn particles at the grain boundaries resulting in decreased corrosion protection. The mechanism behind the corrosion protection of Mg-2Zn-1Ca alloys was discussed.

Development and Validation of Oral Health Knowledge, Attitude and Behavior Questionnaire among Indian Adults.

Background and objectives: The Indian population faces numerous challenges to attain better oral hygiene due to a lack of oral health literacy. For the past 10 years, the prevalence of dental-related conditions in India has become a considerable problem in every state of India. A health-education-based oral health promotion strategy will be an ideal choice for the Indian population instead of endorsing conventional oral health promotion. The use of unsuitable tools to measure may lead to misleading and vague findings that might result in a flawed plan for cessation programs and deceitful effectiveness. Therefore, the research aimed to develop and validate an instrument that can assess the oral health knowledge, attitude and behavior (KAB) of adults in India. Materials and Methods: This study was carried among adults in India, who live in Chennai, Tamil Nadu. A questionnaire was fabricated and then validated using content, face, as well as construct. The knowledge domain was validated using item response theory analysis (IRT), whereas exploratory factor analysis (EFA) was used to validate the behavior domain and attitude. Results: Four principal sections, i.e., knowledge, attitude, demography and behavior, were used to fabricate a questionnaire following validation. Following analysis of item response theory on the knowledge domain, all analyzed items in the domain were within the ideal range of difficulty and discrimination. The Kaiser-Meyer-Olkin measure of sampling adequacy was 0.65 for the attitude and 0.66 for the behavior domain. A Bartlett's test of sphericity was conducted and demonstrated that outcomes for both domains were highly significant (p < 0.001). The factor analysis resulted in three factors with a total of eight items in the attitude domain and three factors with a total of seven items in the behavior domain depicting satisfactory factor loading (>0.3). Across the three factors, i.e., knowledge, attitude and behavior, internal consistency reliability was tested using Cronbach's alpha, and the values obtained were 0.67, 0.87, 0.67, and 0.88, respectively. Conclusions: The findings of this study that assessed validity and reliability showed that the developed questionnaire had an acceptable psychometric property for measuring oral health KAB among adults in India.

Confirmatory Factor Analysis of Knowledge, Attitude, and Behaviour Questionnaire towards Oral Health among Indian Adults.

Background: Oral health-related conditions are among the common conditions seen in adults in India. The usage of inappropriate measurement tools that are unvalidated may result in deceptive and imprecise findings that might lead to substandard plans for cessation programs and ineffectiveness. This study was conducted to validate a questionnaire that can assess the factor structure of knowledge, attitude, and behaviour towards oral health among adults in India by confirmatory factor analysis. Methods: Simple random sampling was conducted among adults in India. A total of 260 adults participated in this study. The knowledge, attitude, and behaviour (KAB) questionnaire on oral health was circulated among the adults who were willing to participate in the study after it was explained to them, and the questionnaires were retrieved once they completed. Software R version 3.6 was used to analyse the data of this study. Robust maximum likelihood was utilized for the assessment due to the violation of multivariate normality assumption. For attitude and behaviour domain, a three-factor model was used for measurement model validity and construct validity. Results: The confirmatory factor analysis of the three-factor model for the 26-item KAB questionnaire on oral health gave sufficient goodness-of-fit values and the measurement model exhibited ideal convergent and discriminant validity following model re-specification. The three-factor model was tested to obtain measurement model validity and construct validity for attitude and behaviour domains. The results of this study gave a statistically significant value (p < 0.001), with χ2 (df) values of 39 (7) and 28 (11) for attitude and behaviour domains, respectively. Conclusions: The KAB oral health questionnaire used in this study has a valid measurement model and reliable constructs. It was found to be an ideal tool to measure the KAB towards oral health among adults in India.

Development of rare-earth oxide reinforced magnesium nanocomposites for orthopaedic applications: A mechanical/immersion/biocompatibility perspective.

Magnesium-Zinc based nanocomposites containing cerium oxide nanoparticles were developed in the present work. A systematic study on their microstructure, mechanical properties, in vitro degradation behaviour, and cytotoxicity are presented. It was found that the developed nanocomposites exhibited excellent strength and toughness that are superior to the commercially available magnesium alloys. From corrosion perspective, nanocomposites exhibited reduced pH increase compared to pure Mg with Mg-0.5Zn/0.5CeO2 showing the least corrosion rate. Moreover, the developed nanocomposites exhibited no cytotoxicity to MC3T3-E1 pre-osteoblast cells. Based on the above findings, the feasibility of Mg-Zn/CeO2 nanocomposites for use as orthopaedic implants is systematically discussed. This study provides an insight into the development of new high-performance Mg alloy-rare earth oxide (REO)-based nanocomposites with superior mechanical properties and corrosion resistance while effectively avoiding the possible standing toxic effect of RE elements.

Hollow silica reinforced magnesium nanocomposites with enhanced mechanical and biological properties with computational modeling analysis for mandibular reconstruction.

The present study investigates Mg-SiO2 nanocomposites as biodegradable implants for orthopedic and maxillofacial applications. The effect of presence and progressive addition of hollow silica nanoparticles (0.5, 1, and 1.5) vol.% on the microstructural, mechanical, degradation, and biocompatibility response of pure Mg were investigated. Results suggest that the increased addition of hollow silica nanoparticles resulted in a progressive increase in yield strength and ultimate compressive strength with Mg-1.5 vol.% SiO2 exhibiting superior enhancement. The response of Mg-SiO2 nanocomposites under the influence of Hanks' balanced salt solution revealed that the synthesized composites revealed lower corrosion rates, indicating rapid dynamic passivation when compared with pure Mg. Furthermore, cell adhesion and proliferation of osteoblast cells were noticeably higher than pure Mg with the addition of 1 vol.% SiO2 nanoparticle. The biocompatibility and the in vitro biodegradation of the Mg-SiO2 nanocomposites were influenced by the SiO2 content in pure Mg with Mg-0.5 vol.% SiO2 nanocomposite exhibiting the best corrosion resistance and biocompatibility when compared with other nanocomposites. Enhancement in mechanical, corrosion, and biocompatibility characteristics of Mg-SiO2 nanocomposites developed in this study are also compared with properties of other metallic biomaterials used in alloplastic mandibular reconstruction in a computational model.

Strength retention, corrosion control and biocompatibility of Mg-Zn-Si/HA nanocomposites.

Owing to the poor load-bearing ability and apparent cytotoxicity of polymeric and ceramic materials, magnesium-based materials can be an ideal substitute for bone repair applications. Magnesium is bioresorbable, unlike other metallic materials like titanium and stainless steel, has excellent biocompatibility, compressive strengths and elastic modulus similar to the natural bone, which circumvents the need for secondary surgery post-implantation in vivo. Against this background, in this study, magnesium-based nanocomposites were developed by using hydroxyapatite bioceramic as a nano reinforcement. Magnesium-based alloys were synthesized using selective alloying elements and hydroxyapatite incorporated nanocomposites were processed using the disintegrated melt deposition technique. The microstructure characterization revealed that the addition of hydroxyapatite resulted in superior grain refinement of the magnesium alloy matrix. The addition of hydroxyapatite improved the yield strength of the alloy matrix and displayed superior strength and ductility retention post corrosion for 21 days, under compression loading. The presence of hydroxyapatite improved the hydrophilicity of the alloy matrix thereby aiding the biocompatibility properties with improved corrosion resistance, level 0 cytotoxicity, and high cell attachment. Hence, the present study strongly suggests that magnesium alloy-based hydroxyapatite nanocomposites can be a suitable candidate for bone repair applications.

Biomechanics of alloplastic mandible reconstruction using biomaterials: The effect of implant design on stress concentration influences choice of material.

INTRODUCTION: Mandibular endoprostheses have been explored extensively as potential methods of alloplastic reconstruction. Studies, however, have demonstrated that for segmental mandibular defects, there are challenges associated with loosening. Another method recently introduced in clinical settings is popular as a design for patient-specific implants for segmental mandibular defect and involves a tray (filled with bone) over the defect with wings on both sides secured with screws. Our aim was to investigate which design better withstands the forces of function since studies have presented favourable results with regard to the wing design. MATERIALS AND METHODS: Two designs, an endoprosthesis with stems and wings were modelled. Finite element analysis was performed, and geometric data obtained from a human-sized mandible. A continuity defect of 20 mm was created digitally at the right mandibular molar region and the modelled segments combined with the endoprosthesis. Boundary conditions were set, and 300-N vertical loads applied in the incisor region. The stress concentrations and displacements were evaluated for the titanium alloy (Group 1-Stem) (Group 2-Wing) and the polycaprolactone (PCL) (Group 3 with stem, Group 4 wing design). RESULTS: For the titanium stem (Group 1), the stress values were in the 557-803 MPa range. The titanium wing (Group 2) design showed markedly reduced stress values in the 20-68 MPa range. The stresses observed for the PCL(Group 3) were in the 66-110 MPa range, and the stress concentration in the PCL wing (Group 4) was observed in the wing and body regions of the scaffolds in the 8-42 MPa range. CONCLUSION: The wing design decreased the areas of stress concentrations significantly compared to an endoprosthesis. PCL alone did not have adequate strength to withstand forces applied even in a design that reduced stress concentrations significantly.

Osteogenic Potential of Graphene in Bone Tissue Engineering Scaffolds.

Scaffolds are physical substrates for cell attachments, proliferation, and differentiation, ultimately leading to tissue regeneration. Current literature validates tissue engineering as an emerging tool for bone regeneration. Three-dimensionally printed natural and synthetic biomaterials have been traditionally used for tissue engineering. In recent times, graphene and its derivatives are potentially employed for constructing bone tissue engineering scaffolds because of their osteogenic and regenerative properties. Graphene is a synthetic atomic layer of graphite with SP2 bonded carbon atoms that are arranged in a honeycomb lattice structure. Graphene can be combined with natural and synthetic biomaterials to enhance the osteogenic potential and mechanical strength of tissue engineering scaffolds. The objective of this review is to focus on the most recent studies that attempted to explore the salient features of graphene and its derivatives. Perhaps, a thorough understanding of the material science can potentiate researchers to use this novel substitute to enhance the osteogenic and biological properties of scaffold materials that are routinely used for bone tissue engineering.