Synthesis of Light Curable Degradable Materials for on Demand Manufacturing of Maxillofacial Implants

头部和颈部的重建通常是创伤的结果，如道路交通事故或疾病，特别是头部和颈部癌症（一种高度侵袭性的癌症，也是男性中第四常见的癌症）。它也是少数几种患病率增加的癌症类型之一，在过去十年中增加了25%），这可能导致生理功能的显著丧失以及毁容，这可能导致广泛的慢性长期心理问题。用于重建的方法可以包括骨移植物，包括大量同种异体移植物和合成物，以及利用复杂的金属基板和螺钉系统。根据重建所需的组织范围，骨移植可能涉及主要的收获和随后的重新植入，例如整个肋骨。很明显，当前的技术和方法还有很大的改进空间。增材制造或3D打印已经成熟，与传统制造方法相比具有许多优势。其中一个主要的好处是，它允许生产一次性组件，从而容易地生产定制的植入物。大多数打印方法使用基于粉末的方法和融合技术，如激光烧结来生产最终器械。这些融合方法是有用的，因为与基于挤出的方法相比，它们允许加工更广泛的材料。使用化学固化系统可能是一种选择，但这需要在挤出之前进行预混合，这会引入其自身的复杂性以及引发剂的毒性问题。然而，3D打印仍处于植入设备完全采用的早期阶段，因为它仍然有一些技术障碍需要克服：（1）可以以合理的空间分辨率打印、可降解并且可以命令固化/固化的可用材料的范围非常有限，以及（2）目前正在研究用于熔融沉积建模的许多材料，在英国，很少有小组专注于开发用于增材制造的全新材料。我们正在寻求的一个选择是开发许多不同的光固化聚合物系统，并从第一原则进行设计，即定义需求，然后设计单体。我们部门的工作已经产生了一系列高度创新的，反应性和生物活性的可降解复合材料，可以通过光固化途径聚合。这提供了优于当前系统的显著优点，因为它可以无菌地供应并且准备以盒格式打印，从而允许按需打印无菌且准备植入的装置。在该领域中要记住的其他因素之一是，虽然在增材制造领域中存在对高度精确制造的显著推动，（近净形）器械，对于颌面部使用，这不是一个驱动因素，因为将通过CT和/或MRI数据集定义待植入的器械，其固有分辨率限值约为0.5- 1 mm，在我们提出的制造系统的能力范围内。

Reconstruction of the head and neck region is usually the result of trauma such as road traffic accidents or disease, in particular head and neck cancer (a highly aggressive cancer and also the 4th most prevalent in males. It also is one of the few cancer types that is increasing in prevalence with a 25% increase in the last decade) and this can result in significant loss of physiological function as well as disfigurement, which can lead to a wide range of chronic, long-term psychological problems. Methods for reconstruction can include bone grafts including significant volume allografts and synthetics as well as utilisation of complex metal based plate and screw systems. Bone grafting, depending on the extent of tissue needed for reconstruction can involve major harvesting and subsequent reimplantation of for example whole ribs. It is clear there is huge scope to improve on current technologies and methodologies.Additive manufacturing or 3D printing has come of age and offers many advantages over more traditional manufacturing methods. One of the major benefits is that it allows the production of one-off components to be produced and thus lends itself readily to the production of custom fit implants. Most of the print methods use powder based methods and fusion techniques such as laser sintering to produce the final device. These fusion methods are useful as they allow a wider range of materials to be processed compared to extrusion-based methods. Utilisation of chemical cure systems might be an option but this would require premixing prior to extrusion which introduces its own complexity, as well as toxicity issues with initiators. However, 3D printing is still in the early stages of being fully adopted for implant device use as it still has some technical hurdles to overcome: (1) there is a very limited range of materials available that can be printed at a reasonable spatial resolution, are degradable and can be command set/cured and (2) many of the materials currently being investigated for fused deposition modelling, can suffer from particle debris that can be loosely adherent to the printed implant device post printing.There are very few groups in the UK focusing on the development of radically new materials for additive manufacturing. One option we are pursuing is to develop a number of different polymer systems that are light curable and designing from first principals, i.e. defining the needs and then designing the monomer. Work within our department has produced a range of highly innovative, reactive and bioactive degradable composite materials that can be polymerised via a light cure route. This offers significant advantages over current systems in that it can be supplied sterile and ready to print in a cartridge format allowing on demand printing of the device, sterile and ready to implant. One of the other factors to be borne in mind in this area is that whilst there is a significant push in the field of additive manufacturing for highly accurate (near nett shape) devices, for maxillofacial use this is not a driver, as the device to be implanted will be defined via CT and/or MRI datasets which have an inherent resolution limit of around 0.5-1mm, well within the capabilities of the manufacturing system we propose.