Evaluating the Spread of Aerosols During Crown Preparation: An In-Vitro Study

Abstract

Background: The severe acute respiratory syndrome (SARS-CoV-2 or COVID-19) brought in an unanticipated dire situation and affected dental practice significantly. Due to the nature of profession, suspension of treatment was imperative as transmission was obscure. Patients did not display evident symptoms and therefore the threat between the dental team and patients was collective. There was a lack of apparent adherence to public health protocols which led to an astronomical number of cases, prolonged period of isolation, oral care neglect and finally decrease in quality of life. However, the current challenging situation ensured better approach and management of patients to optimize standards of care through understanding transmission, reducing spread and enhancing all modalities of treatment. The aim of this study was to explore and evaluate aerosol generation and spread by developing an established laboratory dependent approach strictly simulating prosthodontic aerosol generating procedures.

Materials and method: Restorative crown preparation on the upper right central incisor (#11) and upper right first molar (#16) was performed on a dental manikin in a simulated laboratory. Citric acid (10%) was injected into the waterline and litmus paper was used to demarcate the contaminated regions in the surrounding (30cm distance), the dentist’s faceshield and chest and the simulated assistant’s chest. The chromatic color change (blue to red) was analyzed through Fiji-ImageJ software to evaluate the color intensity (pixels) of aerosol generation.

Results: Contamination was detected at each allocated site. The maximum contaminated mean(SD) surface area was seen at 30cm behind the manikin’s head for both tooth #11 and #16, 157.64(±0.68) pixels and 122.49(±2.89) respectively. Very low contamination levels were detected at the operator’s face-shield for both tooth #11 and #16, 73.35(±0.78) and 65.14(±1.25) respectively. Reduced aerosol splatter was detected as contamination decreased with use of extra oral suction, demonstrating positive results. EOS resulted an average percentage decrease of 20.6% and 19.2% respectively with highest percentage decrease at the operator’s chest.

Conclusions: Aerosol generating procedures such as restorative crown preparation impose high risk of exposure, and with the basis of our findings, mitigation options such as the extraoral suction and personal protective equipment support in reducing spread and chance of transmission.