## 4 Discussion  
The COVID-19 crisis has strained patients, health professionals, and systems worldwide. Given the uncertainties and fluid pandemic situation, policymakers have often implemented strict measures to protect professionals and the general population from the disease, thereby compromising access to treatments and jeopardizing the processes and finances of healthcare systems and businesses [14]. The international community acknowledges that other pandemic scenarios will emerge in the future [24], and it is important to develop guidelines and tools that can protect the population and maintain business continuity amidst any evolving crisis. This is particularly important for dentistry since the saliva and aerosols generated during its procedures may carry different infectious agents that can impact the health of dentists, clinical staff, and patients alike [5; 6; 7; 8; 12; 13]. The hypothesis was accepted, as the D-DART was able to prevent the spread of contaminated aerosols from reaching the face shield and dental chair light. The purpose of the D-DART is to contain and extract aerosols during dental procedures. Hence, it was designed as a clear adjustable tented shield held together by 3D-printed fiber-reinforced nylon hinges that provides folding capabilities for sterilization and storage. The D-DART can be installed by a single operator who adjusts the C-clamps with self-adjusting pads that allow the design to fit dental chairs of different sizes. High-speed air-turbine and ultrasonic scalers are devices able to generate aerosol during ordinary dental procedures. Recently, dental air water spray (3-in-1: air, water, and air + water) has been shown to generate aerosols [25]. The clinician's full-face shield becomes heavily contaminated during aerosol-generating procedures [25; 26]. Several studies have shown this phenomenon using bacterial cultures that do not consider non-bacterial sources of contamination. Herein, we have employed the adenosine triphosphate (ATP) assay, which can also quantify ATP, a key molecule in the metabolism of both mammalian and bacterial cells. ATP quantification has been suggested as a monitoring protocol to determine the extent of contamination generated during aerosol-generating procedures in dental clinics [27]. Our results have shown a significant 10-fold increase in ATP value on the face shield after the dental procedure. Notably, the D-DART was able to prevent such contamination, and the contamination levels of the face shield before and after the treatment were statistically similar (Figure 2 and Table 1). Figure 3: Patient feedback. No major discomfort was reported by most patients treated with the D-DART. Notably, the air contamination increases with the procedure length, spreading from 1 to 4 m away from the patient's mouth and remaining suspended for 20 to 90 min after a procedure has finished [25,28,29]. Hence, the D-DART design includes an extraction valve that can be connected to one of the suction units in the dental chair, and this allows for the safe removal of contaminated air from the tent, directing it to the scavenging system. This extraction valve prevented the environmental spread, as there were virtually no changes in RLU quantification from samples obtained from the dental chair light before and after the treatment (Figure 2 and Table 1). Several administrative and engineering controls have been developed to prevent the spread of microorganisms via aerosols and to protect clinical staff [30]. Although the solutions tried often show acceptable levels of contamination containment, we were unable to determine the patient's opinions and feelings about being treated with such designs. Hence, we have interviewed all the patients that participated in our research to obtain user feedback that will guide design optimization. Overall, patients did not report any major discomfort or concern related to the treatment with the D-DART (Figure 3).