An intra-oral drug delivery system design for painless, long-term and continuous drug release

Abstract

To supplement traditional intravenous injections and other drug delivery pathways, we propose an intra-oral implant system that can allow relatively non-invasive procedures for a drug loading pathway into human blood throughout the maxillary spongy bone. Due to lack of periodontal ligaments and the pulp structure, continuous and steady drug release throughout dental implants may minimize pain, and have therapeutic applications for patients who frequently undergo invasive procedures for conditions such as diabetes mellitus (DM). First we design the intra-oral drug delivery system (DDS) modules based on dental implant fixtures. After the fixture is implanted into the maxilla, the drug is loaded into the DDS structures which are replaceable for drug reloading, replacement or further sterilization. Two different DDS modules are investigated: mechanical and piezoelectric. The mechanical DDS module embedded in the prosthetic abutment combines rotation and screw-driven feeding for drug delivery may achieve quantitative release with an accuracy up to 10μl. On the other hand, the piezoelectric DDS module can output stable volumes over at least 10min with a maximum flow rate of 2.5ml/min, which is adequate for clinical applications. We also use finite element simulations to evaluate the bearing stress around the dental fixture, and the drug flux line during drug release. The bearing stress during drug release is less than 1MPa, which is about 1/10 of the occlusal force. Furthermore, in animal experiments, it is found that insulin release through this DDS module may decrease blood sugar value within 5min, which is as fast as traditional intra-venous injections, and last for 20min. However, more evaluations and improvements are still needed to establish clinical practice and standard procedures, including the development of wireless control techniques and neat module integration.