Table 1.

Update of the main differences in cross-infection prevention in the case of traditional technology vs. CAD/CAM technology in dentistry during COVID-19 pandemic [6].

	Need for	Rationale	Traditional Technology	CAD/CAM Technology	Reference
1	Use of all, adequate and certified PPEs (gloves, surgical mask or FFP2 grade mask, shield, gown, cap, impervious body suit) during impression taking	Avoid microbial and SARS-CoV-2 transmission even in vaccinated DHCWs	Yes	Yes	[32,34,45]
2	Follow standard and transmission-based prevention	Some patients are highly susceptible to SARS-CoV-2 infection. No data on the risk of SARS-CoV-2 transmission during dental practice. Low/medium occupational risk from preliminary data.	Yes	Yes	[32,34,45]
3	Attention to OML, chronic sialadenitis, xerostomia, other oral viral infections	Earlier salivary SARS-CoV-2 than lung lesions. Screening of oxygen saturation (cut off < 93%) by non-invasive pulse oximeter.			[23,24,25,26,27,28,29,30,31,35,36,79]
4	Impression material mixing	Time-consuming procedure. Contaminated glovesand transient microbiota on hands.	Yes	No	[6]
5	Attention during impression	After recovery from COVID-19: the respiratory functional recovery (dyspnoea) could be slow and partial. Abdominal breathing (21%).	++++	Easier procedure	[13,30,31,71]
6	Use of sterile steel or plastic impression tray	As the average survival time ofcoronavirus on plastic or steel surfaces is approximately 48–72 h.	Yes	No	[106,107,108]
7	Time for impression procedure	Reduce physical distancing.	++++	++
8	Good oral hygiene for patients	Reduced oral bioburden.	++++	++	[7,8,12,14,15,16,19,22,35]
9	Pre-procedural mouth rinses (PPMRs) with antimicrobial product	No published evidence regarding their clinical efficacy in reducing SARS-CoV-2 viral load or in preventing transmission. Expected contamination in aerosols and splatter generated during dental procedures and impression contamination.	Yes	Yes	[33,35,45]
10	Laser before impression Proper ventilation Appropriate suction units with in-line filters MIFUs followed for cleaning and disinfection/sterilization of laser, laser pen, and tip	Reduced aerosol and environmental contamination to accommodate for odours, tissue debris, and laser plume suitable for the capture of debris being removed to avoid transmission.	Yes, often for better impression	Yes, not often because of scanner technology	[99]
11	The use of intraoral scanner	Avoid contaminated impression. Patient discomfort, and avoid droplet splatter and aerosol by sneezing and coughing, etc.	Yes, limited with impression scanner	Yes, very often all digital procedures	[6]
12	Impression treatment: early Clean off gross debris and saliva, secured in a plastic leak-proof bag, and sprayed with, or submerged in, a low-level disinfectant following MIFU	Avoid air and environmental contamination. SARS-CoV-2 is a labile infective agent. Spike protein conformation could be influenced by disinfectant pH.	Yes, possible consequence of dimensional stability, impression accuracy, and disinfectant activity	Not needed	[6,105]
13	Dental laboratory prescription Work order	Contaminated paper by SARS-CoV-2, other microbials, blood.	Yes	No, because of e-work order
14	Clean, package, and decontaminate (if possible sterilise) personalised medical devices before sending for repair or maintenance	To reduce infectious bioburden.	Yes	Yes	[105,110]
15	Use single-use shipping materials (e.g., plastic bags with zip-lock bag and client id) Then packing of the impression without hand contact	To avoid infectious bioburden.	Yes, always for impression and medical devices	Yes, limited only for medical devices	[90,105]
16	Casts with synthetic materials	Not deformable. Disinfection easier.	Not possible or advantageous	Yes
17	Proper disinfection of all items prior to dispensing or placing in a client’s mouth	Avoid environment, oral, hand infective agents, and work toxic residues.	Yes	Yes	[90,105]
18	Item transport from laboratory in a C/P pouch labelled with the indication “cleaned” plus in a clean, puncture-resistant container for transport	Avoid hand environmental contamination. Avoid infectious agent transmission, including SARS-CoV-2.	Yes	Yes	[105]
19	DUWL maintenance and control of microbial contamination of city water used for dental care following MIFU	Maintain water quality according to national regulation. Reduce air contamination.	Yes, including quality for alginate impression	Yes, but not important for digital impression	[32,45]
20	Ventilation system and air conditioning system	Maintain fresh air or medical grade air. Some patients affected by chronic diseases are particularly susceptible to COVID-19.	Yes	Yes	[32,45]
21	Position of the work station (PC and scanner) for digital impression: near the fresh air flux in relation to air movement in a clean-to-less-clean flow direction;	Limited clinical contact surface contamination.		Yes	As rationally recommended following other instruments [32,45]
22	Routine cleaning and decontamination of the scanner tip, ward, and system, and all other clinical contact surfaces touched during analogic and digital impression	Surface decontamination using registered hospital-grade disinfectants and against SARS-CoV-2; EPA List N.	Yes, for impression material dispenser	Yes	[50,51,52,53,54,55,56,112]
23	Single-use, transparent, and medical-grade barriers	Reduce contamination and decontamination work.	Yes	Yes, important for the scanner tips	[32,45]
24	Scanner tip sterilization	Inactivation of SARS-CoV-2 by steam in class B small autoclave.		Yes	[19,20,21,22,23,24,25,104]
25	Suction lines and HVE	Limited air and clinical contact surface contamination.	Yes	Yes	[32,45]