A Method for Prevention of Spread of Novel Coronavirus (COVID-19) in a Dental Clinic

Symptoms of COVID-19

Guan et al.³ conducted a study and found that the incubation period for this disease is 4 days. The symptoms include fever 88.7%, cough 67.8%, nausea and vomiting 5%, and diarrhea 3.8%. The median time from the onset of disease to dyspnea is 8 days.

Diagnosis

The diagnosis of COVID-19 is as given in the flowchart (Fig. 2).

Preventive Measures in Dental Clinic

During the oral examination, the patient is asked to rinse the mouth with an antimicrobial mouth rinse to reduce the microbial load in the oral cavity (Kohn et al.⁴; Marui et al.⁵). The dental procedures that are more likely to induce the chances of coughing should be performed cautiously or avoided (WHO 2020a). The use of a 3-way syringe and airotor handpiece that generates aerosol should be avoided or minimized as much as possible. If it is necessary to perform these procedures with a handpiece and 3-way syringe, the healthcare providers in the room should wear a personal protective kit which includes N95 masks, eye protection, gloves, and gowns compulsory. Air from this room should be exhausted directly to the high-efficiency particulate air filter before recirculation.

According to Vandenberghe et al.⁶ intraoral x-ray radiographic technique which is commonly using in dental imaging can stimulate saliva secretion and coughing. Therefore, it is advisable to perform extraoral dental radiographic techniques such as the use of panoramic radiography and cone-beam computed tomography which are appropriate and are safe alternatives during the outbreak of COVID-19.

During the treatment of dental emergency cases to minimize the release of aerosol or spatter, it is advised to use rubber dams⁷ and high-volume saliva ejectors.

Personal Protective Equipment (PPE)

PPE is equipment or specialized clothing worn by a healthcare worker for protection against a hazard. PPE should be in accordance with the OSHA regulations which are as follows:

• CATEGORY 1—Involve exposure to blood, body fluids, or tissues. The employees in this category are instructed to use appropriate protective measures, e.g., dentist, dental assistant, dental hygienist, lab technician.
• CATEGORY 2—Involve no exposure to blood, body fluids, or tissues; however, unplanned category 1 tasks may occasionally be required. The employees in this category should be provided with appropriate protective measures readily available, e.g., workers who may help clean up the office, handle instruments or impression materials, or send dental materials to the laboratory.
• CATEGORY 3—Involve no exposure to blood, body fluids, or tissues, e.g., receptionist.

Sterilization

Common methods that are employed in office sterilization in dentistry include:

• Autoclaving: Long cycle–121°C for 15 minutes at 15 psi, short cycle–134°C for 3 minutes at 30 psi.
• Instruments sterilized are stainless steel instruments, handpieces, cloth goods, glass slabs, dishes, plastic suction tips.
• Chemiclaves: It consists of the use of a combination of liquid chemicals (with <15% water). The parameters for sterilizing are 131°C for 30 minutes at 20 psi
• Instruments sterilized are hand instruments, handpieces, carbon and diamond burs, orthodontic wires, endodontic instruments.
• Hot air oven 160 to 170°C for 1-hour instruments disinfection.
• Instruments and operatory surfaces can be classified as
  • Critical: Instruments that penetrate tissue or touch bone, e.g., scissors, forceps, elevator, scaler. These must be autoclaved.
  • Semicritical: Instruments that touch mucous membrane but do not penetrate, e.g., mouth mirror probes, tweezers, amalgam carrier. Can be either autoclaved or subjected to high-level disinfection
  • Noncritical: Instruments that contact only intact skin, e.g., spatula, mixing slab, and protective eyewear. These should be subjected to intermediate-level disinfection.

Surfaces to be barriered: This includes light handles of electrical or mechanical controls of the dental unit, and headrest and armrest unit controls of the dental chair. High-speed handpiece couplings and hose, slow speed motor, coupling, and hose. Air/water syringe saliva ejectors, handpiece, and hose. X-ray unit handles and cone bite blocks of the panoramic X-ray unit intraoral digital sensors Radiovisiography equipment .

Dispose of Contaminated Waste Safely

Clinical wastes that are generated in the dental clinic which includes blood-soaked gauges, cotton rolls, extracted teeth, tissue waste, and contaminated sharps such as needles, surgical blades, etc., should be placed in a leak-proof containers or bags that are color-coded or labeled. These containers or bags are tightly sealed and disposed safely as mentioned in (Table 1) to prevent leakage during handling, storage, and transport.

Color Coding and Type of Container

YELLOW (plastic bag) Categories 1, 2, 3, and 6

RED (disinfected container/plastic bag) Categories 3, 6, and 7

BLUE/WHITE (plastic bag, puncture-proof container) Categories 4 and 7

BLACK (plastic bag) Categories 5, 9, and 10 (Table 1)

Infection Control Program for Dental Assistant

The staff must be trained based on following OSHA regulations.

This includes the proper use of universal protection procedures which include PPE, the meaning of color-coding, biohazard symbol, precautions to follow in handling contaminated articles or infectious waste and action required, and who to contact if unplanned and proper work practices and their limitations.