Coronavirus contamination in dental clinics. New systems and operating devices

OBJECTIVES Sanitary emergency of SARS-CoV-2 is radically changing all the procedures in dental clinics. A great number of health-care work­ers resulted affected by Coronavi­rus. Dentists work closely face-to-face with the patients and this con­dition greatly increases the risk for Coronavirus infection. Normal den­tal procedures create a tremen­dous hazard and play a number of risks for contaminations with pa­tient’s saliva and exhaled particles. All patients may be asymptomatic but Coronavirus-positive and may represent a great risk for virus diffu­sion in the dental room and among the personnel and/or other patients. The principal problem in dental of­fice is constituted by the presence of aerosols and spray droplets created by high-speed water-cooled hand­piece, ultrasonic instrument, ultra­sonic scalers and dental air-water spray guns. The second important problem is connected with the long face-to-face of the operators (den­tist and assistants) with patients. The airborne fluctuating particles – composed by saliva, mucus, blood, dentin-enamel debris, smear layer, fragments of resto­rations – can remain floating for a long time in the aerosol tide and are diffused by air vortexes creat­ed by high-speed hand-piece. MATERIALS AND METHODS The study identified different type of droplets and airborne produced by dental-unit chair (DUC) instruments. These droplets and airborne parti­cles are produced by DUC instru­ments and may be immediately in­fected by patient mucus and saliva – and in theory plaque and blood – and diffused around as fluctuating particles. These particles present a diameter from 200 to 2 microns and may remain in air for long time (minutes and hours) and settle in all the surface around DUC. They usu­ally present a ballistic trajectory and may be deviated by turbulences and operator movements. Operator masks, glasses, gown etc. are all exposed surfaces that may be fast contaminated. Also boxes, floor and devices in the dental room may be covered by a layer of droplets. Several new devices and new op­erative techniques were recently developed to try to reduce the spray diffusion and to limit the risk for operator contamination. A new designed device is constituted by a double rubber-dam arch with a sliding suction pipe able to uptake spray produced in the mouth and by the nose. The device and other types of lip oral cannulas consis­tently reduce the spray diffusion. Other additional innovative proce­dures for operators are represent­ed by the use of specific water­proof sprayhood to prevent any droplets contact with masks (FFP2/FFP3) and eyes and by Tynek suites to cover all operator’s body. Finally, all DUC and room disinfection procedures must be evaluated to prevent (and to re­move) droplets and particles de­posits from the surfaces. Additional tailored procedures must be standardized, such as the use of FFP2/3, mounthrinses, dis­infection of DUC circuits etc. CONCLUSIONS There is the need for all dental of­fices and dental Clinics to rapidly modify all the clinical procedures in attempt to reduce airborne and spray droplets. The close contact of the operators with patient’s nose and mouth and the potential pres­ence of virus into mucus and saliva create a tremendous hazard due to the production of DUC spray. Again, there is a need for Universi­ties, Dental Clinics and Hospitals to protect students, workers and patients with new tailored opera­tive procedures. CLINICAL SIGNIFICANCE In this position paper, it is support the concept that we need major and rapid reorganization of dental office procedures. The main concept is to restrict the generation of dental spray and use adequate procedures to prevent diffusion in dental offices. New tailored operative procedures are proposed after the evaluation of high risks for airborne and dental spray droplets production and con­tamination dynamic routes. The use of powerful novel suction cannula designed for fast spray/saliva drop­lets aspiration and the use of inno­vative sprayhoods and body suites for dental-care worker protections are important procedures to prevent virus transmission in dental office. Additional procedures may be stan­dardized to remove droplets from all room surface.