Which comes first, the mask or the gown?

Dental Elf link


As the profession starts planning its phased return to clinical work in dental practice I thought it would be a good time to look through the updated ‘COVID-19: personal protective equipment use for aerosol generating procedures (AGPs)’ from Public Health England (PHE, 2020), and I became immediately confused as I referred back to my oral surgery training. Which comes first, the mask or the gown? It was quite challenging to find any recent primary research papers on surgical donning protocols so  I have referenced a recent protocol from the NHS Foundation Trust (Newcastle_Hospitals, 2017). The two protocols are presented below (See Table 1.).

Public Health England

donning instructions for AGPs

Newcastle upon Tyne Hospitals standard surgical protocol
1.     Remove jewellery 1.    Remove jewellery
2.     Tie hair back 2.    Tie hair back + disposable surgical cap
3.     Hand hygiene 3.    Respirator/surgical mask
4.     Gown 4.    Eye protection/visor
5.     Respirator 5.    Hand hygiene
6.     Eye protection/visor 6.    Gown
7.     Gloves 7.    Gloves

Table 1. Comparative donning protocols

The protocols diverge after Stage 2 where the standard surgical protocol involves wearing a surgical cap to prevent the possible contamination of the sterile field by falling hair, but also to prevent contamination of the hair during AGP’s/surgery. The protocol then goes, respirator/surgical mask, eye protection, hand hygiene, gown, and finally gloves. This process reduces the risk of cross contamination of the hands, gown, and gloves prior to treatment. The PHE guidance flips the protocol around where the hands are washed, then the gown, respirator, eye protection, and finally gloves are donned. The contentious area is that if the PPE following the PHE protocol needs to be replaced for the next patient there is an increased risk of cross contamination from the clinicians hands as they have now touched the head, face, ears and gown prior to gloving , this could be reduced in the standard surgical protocol. It would appear that the PHE guidelines are possibly based on an American Centre for Disease Control document from 2007(CDC, 2007) regarding ‘isolation precautions for preventing transmission of infectious agents in healthcare settings’ which then evolved into their ‘PPE guidelines for coronavirus disease’ (CDC, 2020). These guidelines were developed for treating patients in isolation wards where the number of actively infected individuals would be close to 100% (WHO, 2020) rendering cross contamination negligible as all the patients already have the disease.

At present there is a high degree of uncertainty over the prevalence of infected/recovered individuals in the population who could attend a dental surgery for treatment, this uncertainty increases the possibility of cross infection via the sessional use of PPE if an asymptomatic patient should attend for treatment. This also holds true if the PPE is going to be changed between AGPs as there is also a risk of cross contamination of the new PPE, wearer, and surgery environment if doffing and re-donning is not performed perfectly. In a study by Phan and co-workers they found that 11% of scrub samples, and 7% of face samples were positive for respiratory virus after doffing (Phan et al., 2019b), and overall 90% of observed doffing was incorrect (Phan et al., 2019a). As a precautionary principle perhaps these small but important changes in the donning of PPE should be considered; mask, visor, hand hygiene, then gown and gloves. The concern here is not about maintaining sterility as in routine surgery but trying to avoid virus transfer to the new PPE while we await more data on the risk posed by AGPs of dental origin to both the patients and the dental team.

Disclaimer:  The article has not been peer-reviewed; it should not replace individual clinical judgement, and the sources cited should be checked. The views expressed in this commentary represent the views of the author and not necessarily those of the host institution. The views are not a substitute for professional advice.


NEWCASTLE_HOSPITALS. 2017. Surgical Scrub, Gown and Glove Procedure [Online]. The Newcastle upon Tyne Hospitals NHS Foundation Trust. Available: http://www.newcastle-hospitals.org.uk/downloads/policies/Infection%20Control/SurgicalScrubGownandGloveProceduresPolicy201706.pdf [Accessed].

PHE.2020. PHE COVID-19 Donning quick guide gown version [Online]. Public Health England. Available: https://www.gov.uk/government/publications/covid-19-personal-protective-equipment-use-for-aerosol-generating-procedures [Accessed].

CDC. 2007. Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings (2007) [Online]. Available: https://www.cdc.gov/infectioncontrol/guidelines/isolation/index.html [Accessed].

CDC.2020. Using Personal Protective Equipment (PPE) [Online]. Available: https://www.cdc.gov/coronavirus/2019-ncov/hcp/using-ppe.html [Accessed].

PHAN, L. T., MAITA, D., MORTIZ, D. C., WEBER, R., FRITZEN-PEDICINI, C., BLEASDALE, S. C., JONES, R. M. & PROGRAM, C. P. E. 2019a. Personal protective equipment doffing practices of healthcare workers. Journal of occupational and environmental hygiene, 16, 575-581.

PHAN, L. T., SWEENEY, D., MAITA, D., MORITZ, D. C., BLEASDALE, S. C., JONES, R. M. & PROGRAM, C. D. C. P. E. 2019b. Respiratory viruses on personal protective equipment and bodies of healthcare workers. Infect Control Hosp Epidemiol, 40, 1356-1360.

PHE. 2020. PHE COVID-19 Donning quick guide gown version [Online]. Public Health England. Available: https://www.gov.uk/government/publications/covid-19-personal-protective-equipment-use-for-aerosol-generating-procedures [Accessed].

WHO 2020. Rational use of personal protective equipment for coronavirus disease (COVID-19): interim guidance, 27 February 2020. World Health Organization.

EAO 22nd Scientific Meeting Dublin

The European Association for Osseointegration meeting opened on Wednesday evening in Dublin, Ireland . The conference theme being ‘Preparing for the Future of Implant Dentistry’.

Famine Ship - Jeanie Johnston Dublin
Famine Ship – Jeanie Johnston Dublin

On the Thursday morning we started with a presentation about the importance of maintaining the bone supporting the teeth and gums after extraction. In a normal extraction we lose 50% of the supporting bone within 4 months. This volume of bone loss can make it difficult to restore the missing tooth later both functionally and aesthetically. Bone loss can however be reduced to about 20% with the immediate use of bone substitutes placed in the extraction socket at the time of extraction making speeding up healing and  future restoration of the space more predictable.

The afternoons title was ‘Treatment planning for success-how to get in right.’ and was presented by Dr Mark Pinsky a dentist who is also a commercial airline pilot. The theme revolved around the adoption of airline style checklists to reduce errors in surgery. As a side note we have been using these checklists in the practice for the past two years already and find them extremely useful as treatments and patients medical histories get more complex.


Friday morning we discussed the increasing problem of infection round dental implants and whether it was an infection or just the body trying to reject the implant, the conclusion was that more research needed to be done into this area but both factors were to a degree responsable.

The afternoon covered treating patients with long-term loss of upper back teeth from a quite minimalist approach to major surgery for cancer patients.

By far the most interesting series of lectures was on saturday morning titled ‘Implants in the Aging population’. In a lot of Western countries there are more over 65 year olds than 5 year olds and we discussed the problem of how to manage dental health in the age group 80-100. In fact the population of 100 year olds will increased by 400% in the next 25 years. The biggest problems were dental health, retaining unhealthy teeth into old age and long-term chronic illness. Though this subject is not a political vote winner we do need to acknowledge its existence and positively take charge of the challenges it presents. One strategy was the use of a single implant to stabilise a lower denture which over 10 years has dramatically improved patients quality of life at a significantly reduced cost and level of intervention.I have always found the Saturday morning lectures to be the most thought-provoking and applicable to the real world of dental health.

Trinity College Library - Dublin
Trinity College Library – Dublin


2nd Ziess Dental Symposium London

Carl Zeiss bietet Fortbildungsprogramm für Zahnärzte und Dental-Spezialisten an Carl Zeiss Offers Advanced Training Program for Dentists and Dental Specialists

Yesterday I attended the second dental symposium on surgical microscopy hosted by Zeiss. I think these symposia are great as they bring together some of the most skilled dental surgeons in the world to talk on the advances in micro-surgery. Its quite simple, the better you can see what you are doing the better you can do the surgery.

The first speaker was Prof. Krejci on the ‘Geneva Concept’. In summary decay and gum disease is a highly infectious incurable chronic disease and we acquire the bacteria responsible for it at birth. Therefore since we can’t cure it we need to focus on prevention and conservation of damaged tissues. To quote “There is no such thing as a permanent restoration, they are all temporary until the last one”. The easiest and most cost-effective treatment is early intervention and the use of adhesive materials such as resins and composites. With the use of microscopy we can preserve tooth tissue because it’s so much easier to see small defects and cavities in the teeth and precisely repair them.

Dr Rino Burkhardt’s subject was ‘Minimally invasive periodontal surgery and its effects on wound healing’. In essence success depends on maintaining the microscopic blood supply to promote rapid healing and was best achieved by adopting the skills from the other surgical disciplines such as eye and microvascular surgery.

Dr Domenico Massironi (one of my personal heroes) gave a beautiful presentation on the use of surgical microscopes in aesthetic dentistry. Only with improved vision can we truly assess the quality of our work and achieve the precision that our patients deserve. Check out his video (its only in Italian but that does not matter watch it anyway)

In the afternoon followed three excellent lectures by Prof. Gilberto Debelian, Dr Tony Struttman and Dr Tomas Lang on root fillings, retreating failed root fillings and micro-invasive dentistry. If a tooth can be reasonably saved there are huge advantages to the patient than losing it and hoping that an implant will perform any where as well.This may not have been so 15 years ago but microscopy now allows us to literally look down the root of a tooth which was impossible before then. It’s hard to out engineer nature.

The final presentation was from Oscar von Stetten on using the microscope to document our treatment and communicate what we see down the microscope to colleagues and patients. If our patients truly understand what we as clinicians are trying to achieve the better the treatment outcomes. Below is a picture of a cracked back tooth which helped the patient understand why it hurt every time they bit on it.