Bloodborne pathogen (BBP) is broadly defined as a biologic entity that is transmitted through blood, which causes disease. Health care workers (HCWs), including dentists and auxiliary staff, are at heightened-risk of exposure to these infectious microorganisms. Percutaneous and or transmucosal injuries are the primary mode of transmission for BBP in the workplace. The most common BBPs of the highest concern in dentistry are hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV). ^,,, Universal precautions by the Occupational Safety and Health Administration have reduced BBP exposures over the last several decades. This article aims to review emerging BBPs and modes of transmission that could occur in a clinical dental practice. Through rigorous infection control practices and education, clinicians can robustly break the chain of transmission, thereby safeguarding themselves, auxiliaries, medical waste handlers, patients, and those accompanying. The purview of this article is not that of a scoping review or a systematic review, but is that of a narrative review.

The term “blood-borne” is derived from the old English words “blōd” and “beran,” which mean “carried by the blood”. The word “pathogen” is derived from the Greek words “pathos” and “genēs,” implying “disease-causing”. Communicable diseases (CDs), on the contrary, are defined as “diseases caused by pathogenic microorganisms, such as bacteria, viruses, parasites, or fungi; the diseases can be spread, directly or indirectly, from one person to another.” Bloodborne diseases (BBD) are a subset of CD, when specific pathogens from an infected individual (source), through a medium (blood or any other blood-contaminated secretions and media), gain a point of entry (percutaneous, mucocutaneous, or parenteral) into the healthy person’s (recipient) bloodstream.

Pandemics that sent chills down a physician’s spine included but were not limited to, the Bubonic Plague, the Spanish Flu, the HIV/Acquired immunodeficiency syndrome (AIDS) pandemic, and the COVID-19 pandemic ( Fig. 1 ). Epidemics and pandemics have significantly altered the face of the health care industry including dentistry. Infection control guidelines were limited to a mere verbal transfer of knowledge, until the rise of HBV transmissions in dentistry.

A timeline of the pandemics and epidemics. ^,

Increased prevalence of HIV, HBV, and HCV among HCWs is common due to risk of transmission from contaminated blood and body fluids. The Joint United Nations Programme on HIV/AIDS reported 40 million HIV cases in 2023. According to the World Health Organization (WHO), the global prevalence of HBV and HCV in 2022 was estimated to be 250 million chronic cases and half a billion, respectively.

In dentistry, specialities, namely Oral and Maxillofacial Surgery and Periodontics, reported the highest incidences of blood-borne transmissions. Frequent injuries were also reported during fracture reductions, electrocautery, and various procedures involving the use of high-speed instruments. Subgingival scaling utilizing ultrasonic instruments with concomitant use of high-volume evacuator have been shown to minimize blood-contaminated aerosols in Periodontics. ^, Among general dentists, most injuries reported were due to accidental glove perforation by dental burs, implant drills, improper needle recapping techniques, and other sharp instruments. ^,

Most percutaneous injuries in dental schools are during local anesthetic administration. ^,, The global estimate of needlestick injury (NSI) prevalence among dental students is approximately 40%. This is primarily due to the lack of 2 factors, clinical experience and chairside assistance. ^, Additional factors included poor knowledge regarding the proper management of NSI, as well as prophylaxis protocol. ^, Trends related to occupational exposures in dental schools globally are depicted in Fig. 2 . Generally, there is a high incidence of occupational exposures amongst dental students and interns mainly via percutaneous injuries (see Fig. 2 A), ^,,,,,,,,,, as well as low reporting rates (see Fig. 2 B). ^,,,,,,, The underreporting can be attributed to fear of stigmatization, as well as the implications of such a report ; on the other hand, other studies have reported that students who did not report the incident had little to no perception of risk or thought of the injury as minor. ^, The vast majority of students were fully vaccinated against HBV (see Fig. 2 C); ^,,,,, however, not all were tested for antibody titers. ^, Awareness of what constitutes an exposure to BBPs and the definition is generally below optimum as illustrated in Fig. 2 D. ^,,,

Mapping world trends in dental schools. ( A ) Incidence of exposure to bloodborne pathogens ( B ) Percentage of exposure reported ( C ) Rate of complete immunization against BBPs ( D ) Awareness regarding post-exposure prophylaxis and management. (Map lines delineate study areas and do not necessarily depict accepted national boundaries.)

Studies reveal that more than 30 species can be transmitted by blood from source to recipient. Patients infected by BBDs are potential transmission sources. Clinicians must implement practice protocols in order to ensure safety. A summary of the possible pathogens transmitted by blood and its by-products is given in Table 1 . ^{,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,}

Dentists are at a significantly higher risk of acquiring blood-borne infections, commonly due to percutaneous injuries. These pathogens can also be transmitted through sexual contact, needle sharing, NSIs, maternal transmission during pregnancy, birth, or breastfeeding. ^, Exposure to other potentially infectious materials, body fluids, such as semen, vaginal secretions, saliva, and specific serous fluids; whether visibly tainted or transparent, has the capacity to transmit these pathogens, leading to infectious diseases. Several factors contribute to the risk of transmission in a dental setting ( Fig. 3 ). ^,

Factors contributing toward increased risk of transmission.

Within health care environments, transmission typically arises from but is not limited to percutaneous injury, inadvertent puncture, bites, cuts, abrasions, or mucocutaneous contact with fluids from an infected patient ( Fig. 4 ). In an operative setting, sharp instruments used, such as burs, matrix bands, explorers, and curettes, contribute to the majority of the sharp injuries.

Various modes of transmission in dental setting. OPIM, other potentially infectious material.

Sharps with engineered sharps injury protection or safety-engineered devices encompass a wide variety of tools with various mechanisms, both passive and active, that are designed to shield operators and staff from injuries. These devices have demonstrated significant results in reducing such injuries, particularly ones with passive activation mechanisms that activate automatically during use. ^,,, Instruments, such as retractable needles, blunted suture needles, and self-sheathing syringes, have been shown to reduce NSIs when paired with adequate training programs. ^,, Other ancillary measures aiding in prevention include, but are not limited to, the utilization of magnets, modified suturing and recapping techniques, ^, and modified personal protection equipment (PPE) textiles. ^, It must be noted that these additional materials and modifications may demand considerable training and cost. ^,,,

Many educational programs have been established to promote safer practices. In a relatively recent study, virtual reality (VR) has been employed in training sessions. Using VR, a game of right and wrong choices regarding infection control precautions was designed, and has proven effective in decreasing the incidence of sharp injuries. Moreover, the majority of the trainees describe reduced anxiety levels regarding NSIs and the preventive measures required. Another significant facet of these programs is the sensitization of trainees to the perceived threat of occupational exposure to BBPs. This principle is explained by the Health Belief Model, which suggests that for individuals to adopt preventive behaviors, they must first recognize their vulnerability to a risk (perceived susceptibility), comprehend the potential physical and psychologic consequences (perceived severity), and decide to take action if they believe the benefits outweigh any obstacles. When incorporated into educational programs, this model has been effective in raising awareness about NSIs among HCWs by strengthening their perception of health risks and the importance of preventive measures. ^, Fig. 9 gives a summary of infection prevention guidelines for HCWs.

Infection prevention guidelines for healthcare worker.

Stringent infection control measures in clinical dental practices remains paramount as HCWs navigate the inherent risks associated with BBPs. While longstanding adherence to universal precautions has significantly mitigated exposure risks, the emergence of new pathogens necessitates a proactive and adaptive approach to infection control. A variety of preventative measures and techniques have been proposed, but it is beyond the purview of this review. It is recommended that educational training programs involve hands-on training on the proper usage, handling and disposal of safety devices to ensure safer practices. Moreover, this should go in tandem with adherence to current infection control protocols and post-exposure management guidelines.