Efficacy of Aerosol Reduction Measures for Dental Aerosol Generating Procedures.

Aerosol particles generated by dental procedures could facilitate the transmission of infectious diseases and contain carcinogen particles. Such particles can penetrate common surgical masks and reach the lungs, leading to increased risk for dental care professionals. However, the risk of inhaling contaminated aerosol and the effectiveness of aerosol reduction measures in dental offices remain unclear. The present study aimed to quantify aerosols produced by drilling and scaling procedures and to evaluate present recommendations for aerosol reduction. The concentration of aerosol particles released from the mock scaling and drilling procedures on dental mannequin were measured using a TSI Optical Particle Sizer (OPS 3330) during 15-min sessions carried out in a single-patient examination room. Using a drilling procedure as the aerosol source, the aerosol reduction performance of two types of high-volume evacuators (HVEs) and a commercial off-the-shelf air purifier was evaluated in a simulated clinical setting. Using either HVEs or the air purifier individually reduced the aerosol accumulated over the course of a 15-minutes drilling procedure at a reduction rate of 94.8 to 97.6%. Using both measures simultaneously raised the reduction rate to 99.6%. The results show that existing HVEs can effectively reduce aerosol concentration generated by a drilling procedure and can be further improved by using an air purifier. Following current regulatory guidelines can ensure a low risk of inhaling contaminated aerosol for dentists, assistants, and patients.

Needle-free Mental Incisive Nerve Block:In vitro, Cadaveric, and Pilot Clinical Studies.

The present study aimed to optimize Needle-Free Liquid Jet Injection (NFLJI) for Mental Incisive Nerve Blocks (MINB) and evaluate its clinical safety and feasibility. A MINB protocol was developed and optimized by series of NFLJI experiments in soft tissue phantoms and cadavers, then validated in two pilot Randomized Controlled Trials (RCT). The NFLJI penetration depth was found to be directly proportional to the supply pressure and volume. High-pressure NFLJIs (620 kPa or above) created maximum force and total work significantly greater than needle injections. Low-pressure NFLJIs (413 kPa), however, produced results similar to those of needle injections. Additionally, high-pressure NFLJIs created jet impingement pressure and maximum jet penetration pressure higher than low-pressure NFLJIs. Pilot RCTs revealed that high-pressure NFLJI caused a high risk of discomfort (60%) and paresthesia (20%); meanwhile, low-pressure NFLJI was less likely to cause complications (0%). The preliminary success rates of MINB from cadavers using NFLJIs and needles were 83.3% and 87.5%. In comparison, those from RCTs are 60% and 70%, respectively. To conclude, NFLJI supply pressure can be adjusted to achieve effective MINB with minimal complications. Furthermore, the cadaver study and pilot RCTs confirmed the feasibility for further non-inferiority RCT.

Needle-free injection: Dental infiltration anesthesia.

This study aimed to develop an optimal Needle-Free Liquid Jet Injection (NFLJI) technique for dental infiltration anesthesia and evaluate its clinical safety and feasibility. The fluid dynamics of NFLJI in the dentoalveolar region were investigated using soft tissue phantoms supported by rigid glass. NFLJIs were performed at different incident angles and recorded using a high-speed camera. Accordingly, an optimal NFLJI for infiltration anesthesia was developed and validated on cadavers, then assessed in two pilot Randomized Controlled Trials (RCT): one for validating the safety of optimal NFLJI technique, the other for evaluating its feasibility and safety. High-speed videos showed that perpendicular NFLJIs induced significantly more regurgitation than oblique NFLJIs, which was confirmed in cadavers. Clinical trials revealed that perpendicular NFLJIs induced a high risk of bleeding (83.3%) and laceration (83.3%), whereas oblique NFLJIs induced a low risk of bleeding (33.3%) and laceration (16.7%). Moreover, the preliminary success rates of oblique NFLJIs and needle injections were both 83.3%. The recruitment took 3-5 weeks with a rate of 100%. Oblique NFLJIs could be a promising approach for dental infiltration anesthesia, causing minimal drug regurgitation with a relatively low risk of complication. The pilot RCTs confirmed the feasibility for conducting a non-inferiority RCT.