Metallic biomaterials are engineered systems designed to provide internal support to biological tissues and they are being used largely in joint replacements, dental implants, orthopaedic fixations and stents. Higher biomaterial usage is associated with an increased incidence of implant-related complications due to poor implant integration, inflammation, mechanical instability, necrosis and infections, and associated prolonged patient care, pain and loss of function. In this review, we will briefly explore major representatives of metallic biomaterials along with the key existing and emerging strategies for surface and bulk modification used to improve biointegration, mechanical strength and flexibility of biometals, and discuss their compatibility with the concept of 3D printing.

Metallic Biomaterials: Current Challenges and Opportunities.

The focus in the field of biomedical engineering has shifted in recent years to biodegradable polymers and, in particular, polyesters. Dozens of polyester-based medical devices are commercially available, and every year more are introduced to the market. The mechanical performance and wide range of biodegradation properties of this class of polymers allow for high degrees of selectivity for targeted clinical applications. Recent research endeavors to expand the application of polymers have been driven by a need to target the general hydrophobic nature of polyesters and their limited cell motif sites. This review provides a comprehensive investigation into advanced strategies to modify polyesters and their clinical potential for future biomedical applications.

Biomedical Applications of Biodegradable Polyesters.

Three-dimensional (3D) printing enables the production of anatomically matched and patient-specific devices and constructs with high tunability and complexity. It also allows on-demand fabrication with high productivity in a cost-effective manner. As a result, 3D printing has become a leading manufacturing technique in healthcare and medicine for a wide range of applications including dentistry, tissue engineering and regenerative medicine, engineered tissue models, medical devices, anatomical models and drug formulation. Today, 3D printing is widely adopted by the healthcare industry and academia. It provides commercially available medical products and a platform for emerging research areas including tissue and organ printing. In this review, our goal is to discuss the current and emerging applications of 3D printing in medicine. A brief summary on additive manufacturing technologies and available printable materials is also given. The technological and regulatory barriers that are slowing down the full implementation of 3D printing in the medical field are also discussed.

https://iopscience.iop.org/article/10.1088/1758-5090/aa7279/pdf

Current and emerging applications of 3D printing in medicine.

https://espace.library.uq.edu.au/view/UQ:276b006/UQ276b006_OA.pdf

The influence of alloying and fabrication techniques on the mechanical properties, biodegradability and biocompatibility of zinc: A comprehensive review.

Since the advent of additive manufacturing, known commonly as 3D printing, this technology has revolutionized the biofabrication landscape and driven numerous pivotal advancements in tissue engineering and regenerative medicine. Many 3D printing methods were developed in short course after Charles Hull first introduced the power of stereolithography to the world. However, materials development was not met with the same enthusiasm and remained the bottleneck in the field for some time. Only in the past decade has there been deliberate development to expand the materials toolbox for 3D printing applications to meet the true potential of 3D printing technologies. Herein, we review the development of biomaterials suited for light-based 3D printing modalities with an emphasis on bioprinting applications. We discuss the chemical mechanisms that govern photopolymerization and highlight the application of natural, synthetic, and composite biomaterials as 3D printed hydrogels. Because the quality of a 3D printed construct is highly dependent on both the material properties and processing technique, we included a final section on the theoretical and practical aspects behind light-based 3D printing as well as ways to employ that knowledge to troubleshoot and standardize the optimization of printing parameters.

Photopolymerizable Biomaterials and Light-Based 3D Printing Strategies for Biomedical Applications.

Appropriate selection of the implant biomaterial is a key factor for long term success of implants. The biologic environment does not accept completely any material so to optimize biologic performance, implants should be selected to reduce the negative biologic response while maintaining adequate function. Every clinician should always gain a thorough knowledge about the different biomaterials used for the dental implants. This article makes an effort to summarize various dental bio-materials which were used in the past and as well as the latest material used now.

Implant biomaterials: A comprehensive review.

Statement of the problem: Occasional chipping of porcelain in porcelain fused to metal restorations remains a problem till now. Inappropriately controlled firing temperature is considered to be one of the potential causes of this failure. The aim of this study was to evaluate the micro structural properties of metal-ceramic interface of porcelain fused to metal (PFM) restorations at different firing temperatures. o Material and methods: Porcelain was fused to a base metal al loy at 5 dif ferent firing temperatures between 930-990C. The micro structural observations of the porcelain-metal interface were made using X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy and micro hardness studies. Clinical Implication: Size and number of pores present in the porcelain metal interface increased on increasing or decreasing temperature from the optimum firing value, which could lead to long term porcelain chipping or fracture. o Results: Less number of pores with smaller diameter were found in the sample fired at 975C. Micro hardness values also decreased with increasing variation from the recommended firing temperature. Several oxides (CrO , NiO and AlO ) and inter 2 3 2 3 metallic compounds (CrSi, AlNi) were formed at the porcelain metal interaction zone. 2 3 Conclusions: Presence of large size or number of pores in the metal ceramic interaction zone caused by incorrect firing temperatures may trigger crack propagation along the interface, causing eventual failure of porcelain fused to metal restorations.

Effect of Firing Temperatures on Interface of Porcelain Fused to Metal Restorations: An In Vitro Study

doi: 10.1111/j.1741-2358.2011.00519.x



Management of a post-radiotherapy xerostomic patient – a case report



Objective:  The objective of the study was to fabricate complete denture with palatal reservoir filled with artificial saliva for a post radiotherapy edentulous patient.



Background:  Xerostomia is a subjective complaint rather than a disease. It is caused by irradiation, medication, Sjogren's syndrome & neurological factors such as stress. Radiotherapeutic treatment of head and neck cancer patients often causes long term dysfunction involving their salivary function, swallowing capabilities & taste. All three of these domains are affected by radiation- induced damage to the salivary glands. This in turn results in poor retention of complete denture, frequent trauma to alveolar ridge & other oral infections. All these events drastically affects quality of life of ageing patients.



Material and Method:  A complete denture in heat cure acrylic resin was fabricated in which a palatal reservoir was made on the palatal side.



Results:  Problems arising due to xerostomia were reduced to a great extent.



Conclusion:  Prosthodontic management of Xerostomic patient include several techniques. This paper presents a case report of post radiotherapy edentulous patient in which complete denture with palatal reservoir filled with artificial saliva was fabricated.

Management of a post-radiotherapy xerostomic patient – a case report

Parkinson’s disease is an idiopathic disorder of the central nervous system, characterized by resting tremors, muscular rigidity, slow and decreased movements. Oral rehabilitation of these patients requires special care, especially in those cases where the patient’s socioeconomic status is not good and patient cannot come several times for fabrication of a complete denture. This clinical report presents a case of a Parkinson’s patient who was completely rehabilitated in 3 appointments using special techniques. Border molding, final impression and jaw relation procedures were done in one appointment by using a custom tray with detachable handles and occlusal rims.

Oral rehabilitation of a Parkinson's patient: A case report.

Objective: Porcelain chipping from porcelain fused to metal restoration has been Achilles heel till date. There has been advent of newer ceramics in past but but none of them has been a panacea for Porcelain fracture. An optimal firing is thus essential for the clinical success of the porcelain-fused to metal restoration. The aim of the present study was to evaluate ceramo-metal interface at different firing temperature using XRD and SEM-EDS analysis. Clinical implication of the study was to predict the optimal firing temperature at which porcelain should be fused with metal in order to possibly prevent the occasional failure of the porcelain fused to metal restorations. Materials and Methods: To meet the above-mentioned goal, porcelain was fused to metal at different firing temperatures (930-990°C) in vacuum. The microstructural observations of interface between porcelain and metal were evaluated using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. Results: Based on the experimental investigation of the interaction zone of porcelain fused to metal samples, it was observed that as the firing temperature was increased, the pores became less in number as well as the size of the pores decreased at the porcelain/metal interface upto 975°C but increased in size at 990°C. The least number of pores with least diameter were found in samples fired at 975°C. Several oxides like Cr 2 O 3 , NiO, and Al 2 O 3 and intermetallic compounds (CrSi 2 , AlNi 3 ) were also formed in the interaction zone. Conclusions : It is suggested that the presence of pores may trigger the crack propagation along the interface, causing the failure of the porcelain fused to metal restoration during masticatory action.

Yashpal Singh

Papers

Implant biomaterials: A comprehensive review.

Effect of Firing Temperatures on Interface of Porcelain Fused to Metal Restorations: An In Vitro Study

Management of a post-radiotherapy xerostomic patient – a case report

Oral rehabilitation of a Parkinson's patient: A case report.

X-Ray diffraction and scanning electron microscopy-energy dispersive spectroscopic analysis of ceramõmetal interface at different firing temperatures.