Table of Contents  
Year : 2020  |  Volume : 12  |  Issue : 1  |  Page : 3-8

Disinfection Trends of Dental X-ray Machines in North American Dental Schools

University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, USA

Date of Submission11-Mar-2020
Date of Acceptance02-Apr-2020
Date of Web Publication12-Jun-2020

Correspondence Address:
Mel Mupparapu
University of Pennsylvania School of Dental Medicine, 240 S 40th Street, Philadelphia, PA 19104
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jofs.jofs_39_20

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Introduction: This study evaluates the trends in the disinfection of the dental X-ray machines in North American dental schools. The methods of disinfection were compared to the Centers for Disease Control (CDC) guidelines. Materials and Methods: A survey posed the question of whether plastic barrier wrap, bag, disinfecting wipes, or a combination were used for infection control of the tube head. Additional information was gathered from the dental schools’ infection policy guides and clinic manuals available online. Results: Of the forty-two Canadian and US dental schools surveyed, 24% used disinfectant wipes, 19% used bags, 19% used plastic surface barriers, and 38% used a combination. Conclusion: The majority of schools used a combination of the three methods, and all institutions abided by the CDC guidelines. As bags are more cumbersome to use with a rectangular collimator, wipes and barriers are arguably better methods to disinfect the X-ray tube head.

Keywords: Centers for Disease Control (CDC), dental disinfectants, infection control, X-ray

How to cite this article:
Mupparapu M, Lo AD. Disinfection Trends of Dental X-ray Machines in North American Dental Schools. J Orofac Sci 2020;12:3-8

How to cite this URL:
Mupparapu M, Lo AD. Disinfection Trends of Dental X-ray Machines in North American Dental Schools. J Orofac Sci [serial online] 2020 [cited 2023 Jun 8];12:3-8. Available from:

  Introduction Top

Disinfection, or the “process that eliminates many or all pathogenic microorganisms, except bacterial spores”,[1] is a universal method used to clean environmental surfaces in dental clinics. The purpose of disinfection is to prevent the transmission of pathogens between patients, dentists, and workers to ensure a safe environment is maintained. While sterilization, or the process that “[renders] a product free of all forms of viable microorganisms”,[1] is another way to prevent the transmission of diseases, it is mainly used for dental instruments. Disinfection is used for environmental surfaces such as the surface of X-ray tube heads.[1] Without adequate disinfection and sterilization, outbreaks can occur, which jeopardizes the well-being of patients.

According to the CDC, disinfectants used in dental clinics can be categorized into three concentration levels: high, medium, and low. High-level disinfectants kill all microorganisms other than bacterial spores; intermediate level disinfectants are Environmental Protection Agency (EPA)-registered with a tuberculocidal claim1. As per the CDC, “Intermediate-level disinfectants might be cidal for mycobacteria, vegetative bacteria, most viruses, and most fungi but do not necessarily kill bacterial spores.” Low-level disinfectants are (EPA)-registered with a HIV and HBV claim;[1],[2] as per the CDC, they “can kill most vegetative bacteria, some fungi and some viruses”.[1] Only the intermediate and low-level disinfectants can be used for environmental surface disinfection, as the high-level disinfectants are used on items such as semi-critical patient care items.[1]

The subject of this survey, the X-ray tube head, is an integral part of the dental X-ray machine, used to obtain radiographs of the patient’s teeth and jaws.[3] According to the CDC, this item is considered a noncritical patient care item, which means it may come into contact with the skin, but not mucous membranes.[4] Since X-ray tubehead is at a low risk for the transmission of infections it does not require sterilization techniques that use heat and steam, but instead can rely on the less vigorous forms of disinfection such as wipes and surfaces barriers. But if proper attention is not paid to the disinfection protocols, patient safety is at risk. According to a study,[5] X-ray equipment and accessories carried a considerable risk of harboring nosocomial bacteria mainly due to poor disinfection protocols by radiology staff. This can put patients at a significant health hazard.[5]

Based on a study conducted in 1989,[6] 87% of North American dental schools successfully disinfected the X-ray tube head. Dental schools at that time mostly used film-based radiography and A/C X-ray machines. The authors also surveyed overall disinfection practices among US and Canadian dental schools. They reported a lower compliance rate (44%) with the disinfection of the control panels that were largely installed within the operatories (as opposed to outside of the X-ray operatories). Today, dental schools have universally adopted digital radiography. There are stringent CDC and OSHA guidelines and fines in place if not in compliance.

Since dental schools design their individualized infection control protocols (based on CDC guidelines) there may be variation in policies. The purpose of this study was to determine the most widely-used methods of disinfection of the X-ray tube head in dental schools across North America. Specifically, the methods investigated included the use of disinfecting wipes, plastic wrap such as adhesive plastic barrier, bags, or combination of the former to disinfect or protect the tube head. The trends of the methods were compared to the CDC recommended guidelines for environmental surface disinfection.

  Materials and Methods Top

This study obtained the University IRB exemption wide protocol # 833013 as a non-human subject research. In order to investigate the methods that the dental schools used to disinfect the X-ray tube head, multiple approaches were used. An informal survey was sent to dental schools across North America through email and telephone calls. Information was also gathered from the official infection policy guides or clinic manuals provided online. This voluntary survey posed the question of whether the dental school used bags, plastic barriers such as surface adhesives, disinfecting wipes, or combination methods [Figure 1] to disinfect the X-ray tube head. After receiving the surveys back from the Schools that responded and incorporating the information that was gathered online, descriptive statistical analysis was performed.
Figure 1 A standard dental operatory showing (arrows) the various areas that need either a barrier protection or a wipe-discard-wipe (two times) technique to comply with CDC disinfection guidelines.

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  Results Top

Forty-two dental schools from across the US (36) and Canada (6) either responded to the survey concerning their respective school’s method of disinfecting X-ray tube heads or had the pertaining information in their infection control policy manuals or clinic manuals online. Of the dental schools surveyed, 24% used disinfectant wipes only, 19% used bags only, 19% used plastic barriers only, and 38% used a combination of the three methods for infection control of the X-ray tube head including the collimator.

Out of 66 US dental schools, information was gathered from 36 schools (55%). The summary of results is noted in [Figure 2]. Out of 10 Canadian schools, information was gathered from 6 schools (60%). The summary of results is noted in [Figure 3].
Figure 2 Showing the distribution of methods of disinfection employed for X-ray tube heads in the U.S. dental schools.

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Figure 3 Showing the distribution of methods of disinfection for X-ray tube heads in Canadian dental schools.

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The total percentage distributions are summarized in [Figure 4]. Based on our data, one hundred percent of the dental schools surveyed for this research adhered to the CDC guidelines.
Figure 4 Showing the comparative percentage distribution of the methods of disinfection of X-ray tube heads among US and Canadian dental schools compared to the total number of North American dental schools.

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  Discussion Top

According to the CDC, X-ray tube heads are considered noncritical patient care items and should be protected from cross-contamination and properly disinfected. In particular, the guidelines determine that the X-ray tube heads should have “surface barriers” that are defined as “clear plastic wrap, bags, sheets”.[7] In order for barriers to successfully protect the environmental surfaces and follow CDC guidelines, they must be “impervious to moisture” and “removed and discarded between patients.[7] If barriers are not used as a protective measure, then the affected items should be “cleaned and then disinfected after each use”[4] using an “EPA-registered hospital disinfectant of low- (i.e., HIV and HBV claim) to intermediate-level (i.e., tuberculocidal claim) activity.[4] EPA-registered products for intermediate-level disinfection could include products that are chlorine-containing, and low-level disinfectants include quaternary ammonium compounds.[8]

The purpose of this study was to evaluate the trends of disinfection of the X-ray tube head across North America as well as determine whether the dental schools adhered to the CDC recommended guidelines. As seen from the results of the study, of the 42 dental schools that provided a survey response, the majority of the schools, 38%, used a combination of the methods to disinfect the dental X-ray tube heads − either plastic wraps or bags primarily, and wipes as an additional measure. The use of this combination could be the most effective if during the patient encounter the X-ray tube head and the barrier become visibly soiled. In this instance, taking off the barrier and disinfecting it with wipes before replacing the barrier would prevent cross contamination.[7]

Although all the surface barriers are considered viable items to protect X-ray tube heads from cross-contamination, in the survey the adhesive backed surface barriers and bags were separated into two categories as they, along with wipes, offer different advantages in terms of safety and overall convenience.

Among all disinfection methods, plastic surface barriers (stickies) appeared to be the most economical based on the market data. Unlike tube head sleeves, which would be used exclusively for protecting the tube head from any contamination, plastic surface barriers and wipes have more diverse functions. The plastic surface barriers can be used to protect items such as the control panel, switches and handles, and wipes can be used to disinfectant other noncritical surfaces such as counters and sinks. Overall, this makes the platic surface barriers and wipes better options when compared to the tube head sleeves.

To guarantee that safety is prioritized in dental clinics, one must ensure that chemicals used to disinfect items are appropriately used. Since bags and plastic barriers do not pose significant health risks (they do not contain chemicals), the main health safety issue concerns the use of wipes to disinfect surfaces. Disinfection fogging (sprays) is no longer recommended due to its adverse health effects.[9]

In terms of convenience, bags are arguably the least appropriate. The size of the bags can be an issue as they can hinder a person’s ability to take effective radiographic exposures. When the bag is too big, some schools reported tying the bag in a knot to prevent it from causing an extra hindrance. If the X-ray tube head has an adjustable rectangular collimator attached, then the management of bags becomes problematic as the bags will impede both the movement of the rectangular collimator and the placement of the rectangular collimator in close proximity to the Extension Cone paralleling (XCP) aligning instrument. Whether or not the collimator is removable (universal rectangular collimator) or adjustable (manufacturer provided), the plastic bag has to be tied with a rubber band around the collimator. By placing the rubber bands on the plastic bags, more infection control issues are generated. If rectangular collimators are used along with a plastic tube head sleeves, the collimators have to be adjusted for anterior and posterior exposures; a tight sleeve around the collimators makes it harder for those adjustments and hence might have a practical limitation as far as the technique is concerned. Furthermore, the CDC labels the X-ray tube head as a noncritical item as it is not likely to come into contact with a patient’s bodily fluid. In fact, noncritical items have had “virtually no risk… documented for transmission of infectious agents”.[1] It appears that using large, bulky bags seem inconvenient when smaller wipes or plastic adhesive barriers can ultimately provide the same protection. It is essential that dental schools comply with the disinfection procedures outlined by agencies such as CDC and Occupational Safety and Health Administration (OSHA).[10] To achieve compliance, dentists and workers should carefully follow disinfection as well as sterilization methods to ensure the prevention of cross contamination between patients. Although the risk of blood borne pathogens to the tube head specifically is low, as there is rarely skin contact, precautions should still be taken to ensure a safe environment for all persons. Failure to comply with the OSHA regulations such as the safety and health standards can lead to fines of up to US $70,000.[11] Although all the surveyed North American dental schools followed the CDC guidelines, since the guidelines themselves allowed for some variation, the schools were able to adopt one or other forms of disinfection protocol for their dental X-ray machines. It is apparent that the disinfection protocols were tied to the overall infection control protocols and policies of the dental schools, and price of the material used for infection control did not make a difference in their implementation.

  Conclusion Top

The purpose of the survey was to analyze the different types of disinfection used for the X-ray machines and the justification for their uses. Of the three methods which included wipes, adhesive plastic surface barriers, and bags, the results showed that the most widely-used method was consistently using a combination of wipes and barriers. This corresponds with the CDC Guideline that states these tube heads should be protected with a barrier or wiped down using low to medium disinfectant as an alternative.

The CDC guidelines should be strictly followed in all dental practice locations. As the compliance to the CDC rules was high, it is essential that dental schools must continue to adhere to the most recent guidelines set forth and maintain the integrity of the radiographic equipment and prevent cross-contamination. However, the guidelines could be more specific. As discussed before, the X-ray tube head is labelled as a noncritical patient care item, and so using wipes or adhesive plastic barriers should provide adequate protection from the transmission of diseases. Although bags are a viable choice, they can be bulkier and actually hinder the radiographic technique. Bags are also generally less practical, unsightly and pose disposal issues given the other options available with more universal applications. Overall, the X-ray tube head should be properly protected to ensure that there is limited cross contamination between patients, and a safer working environment.


The authors would like to thank all Canadian and American dental schools that participated in this survey.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Rutala WA, Weber DJ. Healthcare infection control advisory committee (HICPAC). Guideline for disinfection and sterilization in healthcare facilities, 2008. Available at: (Accessed June 15, 2017).  Back to cited text no. 1
Mupparapu M, Kothari KRM. Review of surface disinfection protocols in dentistry; a2019 update. Quintessence Int 2019;50:58-65.  Back to cited text no. 2
Mupparapu M, Nadeau C. Oral and maxillofacial imaging. Dent Clin North Am 2016;60:1-37.  Back to cited text no. 3
Centers for Disease Control and Prevention. Summary of Infection Prevention Practices in Dental Settings. Available at: (Accessed June 15, 2017).  Back to cited text no. 4
Ochie K, Ohagwu CC. Contamination of X-ray equipment and accessories with nosocomial bacteria and the effectiveness of common disinfecting agents. 2009 Available at: (Accessed October 6, 2018).  Back to cited text no. 5
Katz JO, Cottone JA, Hardman PK, Taylor TS. Infection control in dental school radiology. J Dent Educ 1989;53:222-5.  Back to cited text no. 6
Kohn WG, Collins AS, Cleveland JL, Harte JA et al. Prevention Guidelines for Infection Control in Dental Health Care Settings, MMWR Recommendations and Reports. 2003. Available at: (Accessed June 15, 2017).  Back to cited text no. 7
CDC, MMWR Recommendations and Reports. Appendix C: Methods and Sterilizing and Disinfecting Patient-Care Items and Environmental Surfaces. 2003. Available at: (Accessed June 17, 2017).  Back to cited text no. 8
Centers for Disease Control. Disinfection and Sterilization. Available at (Accessed April 12, 2019).  Back to cited text no. 9
United States Department of Labor. Occupational Safety and Health Administration. Blood borne pathogens. Available at: (Accessed March 26, 2019).  Back to cited text no. 10
Occupational Safety and Health Administration. Section 17: Penalties. OSH act1970. Available at: (Accessed March 26, 2019).  Back to cited text no. 11


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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