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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牙科局麻药可控射流注射

目标：对牙科手术的恐惧是有效牙科护理的常见障碍。一种克服牙科焦虑症的有前途的技术是无针喷射注射，它涉及以高速喷射的形式输送局部麻醉剂，无需针即可穿透口腔粘膜。先前的努力使用了设计用于透皮递送的响亮、不受控制的注射器，但未能在牙科实践中取得显着的应用。方法：在这项工作中，我们展示并验证了一种由静音电机驱动的可控喷射注射装置，用于输送牙科局部麻醉剂。注射器在其远端包括一个新颖的管状附件，它允许在整个口腔内舒适地进行输送。分析了使用该附件导致的预期压力损失。该分析预测，半径为 0.53 mm 的 75 mm 长管状附件将导致可忽略不计的压力损失。为了验证在人体组织中的递送，该注射系统被用于对两具 Thiel 防腐处理的人类尸体的口中进行 18 次注射。这些注射使用锥形束计算机断层扫描 (CBCT) 进行可视化。结果：原型喷射器的台式测试验证了沿附件的预期压力损失。CBCT 扫描表明，流体已成功输送到每个注射部位的所需位置，靠近牙齿的根尖。结论：这些结果验证了这种新型无针注射器的性能，展示了其作为减少牙科焦虑的工具的潜力。为了验证在人体组织中的递送，该注射系统被用于对两具 Thiel 防腐处理的人类尸体的口中进行 18 次注射。这些注射使用锥形束计算机断层扫描 (CBCT) 进行可视化。结果：原型喷射器的台式测试验证了沿附件的预期压力损失。CBCT 扫描表明，流体已成功输送到每个注射部位的所需位置，靠近牙齿的根尖。结论：这些结果验证了这种新型无针注射器的性能，展示了其作为减少牙科焦虑的工具的潜力。为了验证在人体组织中的递送，该注射系统被用于对两具 Thiel 防腐处理的人类尸体的口中进行 18 次注射。这些注射使用锥形束计算机断层扫描 (CBCT) 进行可视化。结果：原型喷射器的台式测试验证了沿附件的预期压力损失。CBCT 扫描表明，流体已成功输送到每个注射部位的所需位置，靠近牙齿的根尖。结论：这些结果验证了这种新型无针注射器的性能，展示了其作为减少牙科焦虑的工具的潜力。这些注射使用锥形束计算机断层扫描 (CBCT) 进行可视化。结果：原型喷射器的台式测试验证了沿附件的预期压力损失。CBCT 扫描表明，流体已成功输送到每个注射部位的所需位置，靠近牙齿的根尖。结论：这些结果验证了这种新型无针注射器的性能，展示了其作为减少牙科焦虑的工具的潜力。这些注射使用锥形束计算机断层扫描 (CBCT) 进行可视化。结果：原型喷射器的台式测试验证了沿附件的预期压力损失。CBCT 扫描表明，流体已成功输送到每个注射部位的所需位置，靠近牙齿的根尖。结论：这些结果验证了这种新型无针注射器的性能，展示了其作为减少牙科焦虑的工具的潜力。临床和转化影响声明 — 我们的可控射流注射装置克服了先前尝试无针注射牙科局部麻醉剂的关键限制。这可以大大减少有效牙科护理的障碍。