Objective: Fear of dental procedures is a common barrier to effective dental care. A promising technique to overcome dental anxiety is needle-free jet injection, which involves delivering local anaesthetic as a high-speed jet capable of penetrating the oral mucosa without a needle. Previous efforts have used loud, uncontrolled injectors designed for transdermal delivery that have failed to achieve significant uptake in dental practice. Methods: In this work, we present and validate a controllable jet injection device driven by a silent electric motor for the delivery of dental local anaesthetic. The injector includes a novel tubular attachment at its distal end, which allows the delivery to be performed comfortably throughout the mouth. The expected pressure loss resulting from the use of this attachment is analysed. This analysis predicted that a 75 mm long tubular attachment of 0.53 mm radius would result in negligible pressure loss. To validate delivery in human tissue, the injection system was used to perform 18 injections into the mouths of two Thiel-embalmed human cadavers. These injections were visualised using cone-beam computed tomography (CBCT). Results: Benchtop testing of the prototype injector verified the expected pressure loss along the attachment. The CBCT scans demonstrated that the fluid was successfully delivered to the desired locations, adjacent to the root apex of the teeth, at every injection site. Conclusion: These outcomes validate the performance of this novel needle-free injector, demonstrating its potential as a tool to reduce dental anxiety. Clinical and Translational Impact Statement- Our controllable jet injection device overcomes key limitations associated with previous attempts to deliver dental local anaesthetic needle-free. This could greatly reduce barriers to effective dental care.

中文翻译：

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牙科局部麻醉药的可控射流注射


目的：对牙科手术的恐惧是有效牙科护理的常见障碍。克服牙科焦虑症的一种有前途的技术是无针喷射注射，它涉及以高速喷射的方式提供局部麻醉剂，无需针头即可穿透口腔粘膜。之前的努力使用了专为透皮给药而设计的大声且不受控制的注射器，但未能在牙科实践中获得显着采用。方法：在这项工作中，我们提出并验证了一种由静音电动机驱动的可控射流注射装置，用于输送牙科局部麻醉剂。注射器的远端包括一个新颖的管状附件，可以在整个口腔中舒适地进行输送。分析使用该附件产生的预期压力损失。该分析预测，75 毫米长、半径 0.53 毫米的管状附件将导致可忽略不计的压力损失。为了验证人体组织中的输送，使用注射系统对两具经过泰尔防腐处理的人类尸体的口腔进行了 18 次注射。使用锥形束计算机断层扫描 (CBCT) 对这些注射进行可视化。结果：原型喷油器的台式测试验证了附件沿线的预期压力损失。 CBCT 扫描表明，液体已成功输送到每个注射部位的所需位置，即邻近牙齿根尖的位置。结论：这些结果验证了这种新型无针注射器的性能，证明了其作为减少牙科焦虑工具的潜力。临床和转化影响声明-我们的可控喷射注射装置克服了之前尝试无针牙科局部麻醉的关键限制。 这可以大大减少有效牙科护理的障碍。