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Background 3D printing (3DP) photosensitive resins are commonly used to produce patient-specific solutions in the fields of medicine and dentistry. These resins are toxic in their liquid state. To ensure that all resin has solidified and parts are safe for use, post-processing must be carried out after printing. Parts are first washed in IPA, allowed to dry, and then post-cured under ultra-violet light (UV), and sometimes heat. As 3DP is commonly utilised for its ability to create custom and rapid solutions, it is expected that a different geometry will be produced almost every time. Currently, post-processing guidance is supplied specific to a material, with the caveat that post-curing times should be extended for larger or complex parts. The aim of this study was to assess the effect of extending post-curing times for photosensitive resin printed parts. Method Two commercially available vat-polymerisation 3DP systems were used to print hollow 60mm diameter spheres. Two opaque white, two opaque black, and two translucent amber resins were used. The spheres were filled with liquid resin, then UV post-cured at intervals of 100, 200, 300, 400 and 500% of the recommended guidance. The spheres were sectioned along the centreline and radial measurements taken of the cured depth. Results The results showed that both translucent amber materials cured to full depth at the 100% interval, whereas none of the white or black opaque materials cured to full depth, even at 500% of the recommended guidance. Conclusions This suggests opacity has a considerable effect on the depth of cure in photosensitive resins, and that the use of opaque resins increases the possibility of uncured resin remaining inside parts.

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BackgroundThree-dimensional printing (3DP) enables the production of highly customised, cost-efficient devices in a relatively short time, which can be particularly valuable to clinicians treating patients with palliative care intent who are in need of timely and effective solutions in the management of their patients’ specific needs, including the relief of distressing symptoms.MethodFour online databases were searched for articles published by December 2020 that described studies using 3DP in palliative care. The fields of application, and the relevant clinical and technological data were extracted and analysed.ResultsThirty studies were reviewed, describing 36 medical devices, including anatomical models, endoluminal stents, navigation guides, obturators, epitheses, endoprostheses and others. Two-thirds of the studies were published after the year 2017. The main reason for using 3DP was the difficulty of producing customised devices with traditional methods. Eleven papers described proof-of-concept studies that did not involve human testing. For those devices that were tested on patients, favourable clinical outcomes were reported in general, and treatment with the use of 3DP was deemed superior to conventional clinical approaches. The most commonly employed 3DP technologies were fused filament fabrication with acrylonitrile butadiene styrene and stereolithography or material jetting with various types of photopolymer resin.ConclusionRecently, there has been a considerable increase in the application of 3DP to produce medical devices and bespoke solutions in the delivery of treatments with palliative care intent. 3DP was found successful in overcoming difficulties with conventional approaches and in treating medical conditions requiring highly customised solutions.