Analysis of workplace injuries in a dental school environment

Australian Dental Journal 1997;42:(2):109-13 Analysis of workplace injuries in a dental school environment R. I. McDonald* L. J. Walsh N. W. Savage Abstract Workplace injuries at the University of Queensland Dental School during the period 1992-1994 were assessed to determine their incidence, and the associated indirect costs, causal factors, and appropriate preventive strategies. Overall, dental chairside assistants experienced a higher incidence of injuries than students both on a per worker and per time basis. Of the injuries with a low risk of cross-infection, burns and scalds from sterilizing equipment, and eye injuries in laboratories were the most common. This emphasizes the importance of wearing appropriate protective equipment in areas outside the treatment zone, and the need for signage and education. Common causes of sharps injuries were burs left in handpieces, two-handed needle recapping, and cleaning of probes in the sterilizing room. Changes to techniques and equipment would prevent such incidents. A range of factors which contribute to the calculation of indirect costs following injuries in the dental workplace are identified. Key words: I n j u r y, workplace safety, sharps, accident p r e v e n t i o n. (Received for publication July 1996. Accepted August 1996.) Introduction Numerous workplace hazards are found in dental practice. Historically, interest has been centred on hazardous chemicals; however, in the past decade, infection control and ergonomics have receive d increased attention. When wo r k - r e l ated injuri e s occur in dental practice, those which invo l ve exposure of staff to patient material tend to cause considerable anxiety. Many dental staff perceive a *Recipient of a Student Scholarship from the Australian Dental Research Fund (now Foundation) Inc. Dental School, The University of Queensland. high risk of contracting serious diseases in this manner, resulting in significant job-related stress. 1 Such high-risk (HR) injuries are sustained by both dental students and experienced dentists, with more than 50 per cent of individuals in each group sustaining a HR injury in a given 12-month period. 2,3 Because of their serious consequences, 4-8 the followup and prevention of these HR incidents is addressed in some detail in national infection control guidelines. 9 Without diminishing in any way the seriousness of HR incidents in the dental workplace, it should be recognized that other injuries which do not carry a risk for acquiring an infectious disease from patients (so-called non-infectious risk (NIR) injuries) can pose a threat to both the health and livelihood of dental staff. These NIR injuries have largely been neglected by the profession in terms of research into their incidence, causes, and prevention. Accidents such as burns and scalds from autoclaves and eye injuries from acrylic and other particulate matter sustained in the laboratory environment are not uncommon, yet may be seen as unavoidable or of low importance. This conflicts with basic principles of health and safety management, which emphasize hazard identification and risk management, and identify the responsibility of the employer to provide a safe place and safe systems of work. While the prevailing focus of health and safety concerns in dentistry has been in the area of infection control, 10 there is a range of other significant concerns and these are now beginning to be addressed. 11 To date there has been no comprehensive analysis of the types of both HR and NIR injuries which occur in contemporary dental practice in Australia. Such data are important for developing both policies and practices in this area and for identifying needs for education and training. While the direct (consumables) cost of infection control measures is well recognized by the dental profession, there are no published data on the indirect costs related to the Australian Dental Journal 1997;42:2. 109

follow-up of both HR and NIR injuries. Against this background, the present study was undertaken with the objective being to identify the hidden costs that are associated with workplace injuries in dentistry as well as factors which may contribute to accident causation. Materials and methods The study sought to obtain objective data on fa c t o rs relating to workplace injuries via a retrospective assessment of injuries occurring in an institutional setting (the Unive rsity of Queensland Dental School). While it was recognized that the learning situation in such an institution does not correspond exactly with the environment of general dental practice, the approach taken offered a number of significant advantages, namely: 1. A stringent system of incident recording had been established (and monitored) for many ye a rs and thus the data were likely to be reliable. 2. There were standard protocols in place for follow-up of incidents, which allowed estimation of the costs of staff time for reporting, counselling, and investigation. 3. There were accurate data for hours worked and salaries paid for each category of worker across the time period. 4. Data from two other sources, namely a central health and safety unit and the government workers compensation department, could be used to crosscheck individual incidents to ensure that a complete record of all injuries had in fact been obtained. All accident report forms completed at the University of Queensland Dental School for the t h r e e - year period of 1992-1994 were collat e d. Because of the differing protocols for follow-up of HR and NIR injuries, these records had already been segregated into HR and NIR groups. To check for injuries not documented in these records, a check was made of data from the University of Queensland Occupational Health and Safety Unit, and the Wo r k e r s Compensation Board of Queensland. The following factors were noted: the number of incidents reported, the occupation of the victim, the cause of the injury, and the work site where the incident took place. Hidden costs were calculated for each accident based on: 1. The lost time of the injured worker. 2. The time taken by the first aid attendant (a registered nurse). 3. The cost of first aid supplies. 4. The time taken by senior staff involved in health and safety management to prepare and process the accident report form and investigate the incident. For each of these parameters the average time per incident over the period was used. From this figure Table 1. Total reported NIR and HR injuries between 1992 and 1994 the salary costs were determined using the salary scales in force at the time. No salary figure was used for students. Of note, the costs of serological tests undertaken as part of the follow-up of HR injuries were not included, these being essentially borne by the Federal Government via the Medicare system. To identify groups at risk and to monitor safety performance over the time period used in the study, the number of injuries were related to both the number of employees and students, and to a specific time frame. Two standard injury statistics were calculated, namely: 1. Frequency rate: The number of injuries for every one million hours worked. 2. Incidence rate: The number of occurrences of i n j u ry for each one hundred wo r k e rs in that cat e g o ry. Results A total of 46 NIR injuries were reported during the three-year period, and of these 28 involved dental assistants. Of note, undergraduate dental students showed a steady increase in the number of injuries over the period (Table 1). No NIR injuries involved postgraduate students or members of the academic staff. There were 135 HR injuries during the three year period (Table 1). Dental students reported the highest number of accidents (N=72), followed by dental assistants (N=55) and postgraduate students/ supervisors (N=8). Overall, the highest number of HR injuries occurred in 1993. NIR injuries to students 1994 1993 1992 Subtotals Total Students 90 NIR 8 6 4 18 HR 21 27 24 72 Dental assistants 83 NIR 9 13 6 28 HR 18 22 15 55 Postgraduates 8 NIR HR 3 2 3 8 All groups 181 NIR 17 19 10 46 HR 42 51 42 135 NIR signifies no risk of occupationally acquired infection from a patient source. HR signifies high risk of occupationally acquired infection. These were distributed in five categories: burns, handpiece bur injuries in a preclinical laboratory setting, eye injuries, sterile sharps injuries, and falls (Table 2). Burns from bunsen burners and molten wax were the most common injury (N=6), followed by eye injuries (N=5) and wounds from sterile needles and scalpel blades (N=4). Four eye injuries resulted from projectile pieces of acrylic during grinding of prostheses in laboratories. First aid for these injuries 110 Australian Dental Journal 1997;42:2.

Table 2. NIR injuries to students and dental assistants Type of injury 1994 1993 1992 Total Burns to skin Students 3 3 6 Assistants 6 4 1 11 Bur penetration Students 2 2 Assistants Eye injury Students 2 2 1 5 Assistants 2 1 1 4 Sharps injury Students 1 3 4 Assistants 1 4 2 7 Falls and collisions Students 1 1 Assistants 2 2 4 Chemical fumes Students Assistants 2 2 included continuous irrigation using an eye wash solution. Fortunately, no permanent eye damage occurred. As expected, the majority of the injuries (14 out of 18) occurred in laboratories, while three occurred in clinics and one in a passageway. N I R i n j u ries to dental assistants B u rns were by far the most common injury (N=11), and these occurred during loading or unloading of autoclave s. None of the incidents involved recently developed jacketed insulated autoclaves. One burns incident was quite serious and because of complications, this resulted in extended time off work for the individual involved. HR injuries to students The most common injury of this type resulted from reaching across a bracket table to pick up an instrument, and scratching an arm or hand on a bur in a handpiece located in its holder (N=28). Needle stick injuries were the next most common (N=22), and the majority of these occurred when attempting to resheath the needle using a two-handed technique, or when disassembling the syringe prior to disposal of the needle. Other causes of HR injuries included: curettes (N=5), ultrasonic scalers (N=3), sickle probes (N=4), and carvers (N=2). There was only a single injury recorded for each of the following identifiable sharps: denture clasps, ligature wire, suture needles, endodontic files, and matrix bands. For postgr a d u ate students and superv i s o rs, injuries were caused by burs in handpieces and ultrasonic scalers (N=2 for each). There was a single injury caused by each of the following: needle sticks, suture needles, and denture clasps. HR injuries to dental assistants The most common cause of a HR injury was a dental probe, which caused a sharps injury either Table 3. Group Hidden costs in NIR injuries 1994 1993 1992 Total $ $ $ $ Students 201 143 80 424 Assistants 223 1653 194 2070 Total 424 1796 274 2494 while cleaning instruments, or when clearing the bracket table at the end of a procedure (N=21). The next most common causes of injury were burs left in handpieces (N=10), and needle sticks during disposal of the needle. Other causes of HR injuries were curettes, carvers, and orthodontic wire (N=2 for each). One injury was caused by each for the following: scalpel blades, denture clasps, endodontic files, wax knives, matrix bands, and gingival margin trimmers. Follow up of all HR injuries involved an assessment of the injury together with first aid, counselling of the individual, and serological testing of the student and patient according to a detailed protocol in place in the institution. In all instances, the events leading to the accident were investigated to identify the improvements in procedure necessary to prevent a recurrence. Appropriate counselling 12 was undertaken prior to any serology being undertaken. Hidden costs The estimated hidden costs for NIR and HR injuries are presented in Tables 3 and 4, respectively. Overall, HR injuries resulted in almost twice the l e vel of indirect (lost salary/lost time) costs compared with NIR injuries. For NIR injuries, the costs for dental assistant injuries were greater than for student injuries, while the converse was true for HR injuries. In the NIR category, there was a substantial cost following a single orthopaedic injury sustained during a fall which resulted in an extended period of sick leave. Frequency rates There were marked differences in the frequency rates (accidents per million hours worked) between students and dental assistants, with a higher frequency rate for assistants during each of the three years for both NIR and HR injuries (Table 5). Across each class of worker, the highest frequency rates occurred in 1993. Incident rates Incidence rates (number of occurrences of injury for each one hundred employees) were higher for Table 4. Group Hidden costs in HR injuries 1994 1993 1992 Total $ $ $ $ Students 602 855 654 2111 Assistants 575 717 511 1803 Postgraduate 129 67 110 306 Total 1306 1639 1275 4220 Australian Dental Journal 1997;42:2. 111

Table 5. Frequency rate statistics Occupation 1994 1993 1992 Students NIR injury 98 69 50 HR injury 339 408 402 Assistants NIR injury 309 446 206 HR injury 618 756 515 Data are the number of accidents per one million hours worked. dental assistants than for students by a substantial margin in each of the three years. For the assistants, both NIR and HR incidence rates increased in 1993 then decreased in 1994. In contrast, NIR incidence rates for students showed a steady increase over the period (Table 6), while rates decreased for HR injuries in the student population. Discussion The results of this study provide insight into the pattern of injuries which occur in a dental workplace and their indirect costs. It should be emphasized t h at while the situation in an institutional and teaching environment is not identical to that encountered in general dental practice, many of the factors which contribute to accidents are present in both settings, and thus the pattern of events in accident causation is likely to be comparable. The present findings indicate that both NIR and HR injuries occur frequently, and both invo l ve significant indirect costs because of lost time on the part of the injured staff member and other staff who provide first aid or follow-up care. Moreover, it should be emphasized that a range of indirect costs exist which were not included in the present study because of the institutional setting in which the study was conducted. These may impact significantly on indirect cost calculations in other practice settings. Such cost factors include: the salary of dentists (rather than dental students), lost time for staff to attend an outside medical practice for serological f o l l ow-up after HR injuries, costs of medical c o n s u l t ations and pathology tests, and loss of discounts or rebates from workers compensation schemes (which vary according to the claim history). The financial impact of lowered morale, retraining, staff redeployment and lost productivity cannot be calculated easily but should also be included when assessing indirect costs associated with injuries. Table 6. Incidence rate statistics Occupation 1994 1993 1992 Students NIR injury 6 4 3 HR injury 15 19 18 Assistants NIR injury 35 50 23 HR injury 69 85 58 D ata are the number of occurrences of injury for each 100 employe e s. A key outcome of the systematic study of accident records is the identification of appropri ate preve n t i ve strategies and educational requirements, rather than the allocation of blame. For example, in the present study it appeared that accidents were more likely to occur in the afternoons of the first weeks of the teaching semesters at which time new dental assistants began their training and students returned from vacation. From this it may be inferred that an orientation to the work environment would be a positive step in reducing injuries, through enhanced staff awareness. A more complete approach to accident prevention would address basic equipment and procedural fa c t o rs rather than relying entirely on human factors such as higher awareness or skill or the wearing of protective equipment. For example, gi ven that the most common sharps injury to students resulted from a bur puncture when reaching across a bracket table to pick up an instrument, the placement of handpiece h o l d e rs and the bracket table itself should be addressed, as well as the habit of leaving burs engaged in the handpiece chuck when not in use. Similarly, since most needlestick injuries occurred when attempting to resheath the needle using a twohanded technique, changing to a one-handed b ayonet/scoop recapping technique would be a p p r o p ri ate. For dental assistants, the common occurrence of a sharps injury when cleaning probes by hand is best addressed through an elimination approach, that is, using an ultrasonic cleaner or instrument washer rather than routine hand cleaning. As could reasonably be expected, when these various measures have been introduced a substantial decline in the incidence of these injuries has occurred. Of note in the present study was the finding that dental assistants as a group experienced a much higher incidence of injuries than students despite the fact that the latter outnumber the former by approximately seven to one. As shown by the frequency rates, on the basis of probabilities dental assistants are far more likely than students to sustain both HR and NIR injuries. The relative vulnerability of the assistants is even more apparent when the actual hours of contact time in the clinical or dental laboratory environment are taken into account, as occurs in the calculation of incidence rates. These ranged from 4 to 12 times greater for assistants than for students. The majority of NIR injuries to assistants were burns caused by accidental contact with the rim of the autoclave chamber during loading and unloading. S e veral basic causes of these accidents can be identified: a procedure in which it is necessary to reach inside a hot chamber, a lack of signs on the equipment wa rning of the hazard, and an env i r o n m e n t in which staff are often working under significant time pressures. The majority of these injuries were 112 Australian Dental Journal 1997;42:2.

sustained by young, relatively inexperienced staff who had just commenced their training. In response to these data, a preventive strategy has been devised which includes education with respect to the hazard and proper techniques, combined with the implem e n t ation of appropri ate personal protective equipment, namely, elbow-length heat-proof gloves. In the 18 months since these measures we r e adopted, only one injury of this type occurred, and in this instance the staff member was not wearing the heat-proof gloves provided. A wor rying statistic which emerged in this study was the high rate of eye injuries sustained by students working in dental laboratories. The value of protective eyewear in a working environment in which large amounts of particulate matter (and larger projectiles) are generated is self evident. Of interest, compliance problems regarding the use of protective eyewear by Australian dentists in the clinical setting have also been identified. 13 This i m p o rtant area should receive much gr e at e r attention in the training of all dental health care workers, and the wearing of protective eyewear should be made compulsory in laboratories as well as clinical t r e atment areas. In addition, all clinical and l a b o r at o ry facilities should have an identifiable eyewash station and one person should be responsible for its maintenance. In terms of accident causation, there is a logical progression of events which eventually results in an accident. The basic causes of accidents are considered to be the root or underlying causes. These include lack of staff training and education and failure to p r ovide proper monitoring or supervision. Su b s t a n d a r d conditions include poorly designed equipment, insufficient warning mechanisms, poor lighting, and slippery surfaces. Substandard practices include a failure to follow accepted practices or to use protective devices. Applying this schema to the accidents investigated in the present study allows the distinction between these various elements to be made. For example, a common event in accident causation was failure to wear appropriate protective equipment (for example, eye injuries in the dental laboratory). This substandard practice results from inadequat e education and training, and lack of supervision. These management factors need to be included when developing strategies for accident prevention, rather than simply concentrating on worker factors as is usually the case. Conclusions This study has demonstrated that both HR and NIR injuries are sustained in a dental practice environment, and these result in significant and easily identified costs. Practice managers should ensure that accident records are assessed retrospective l y from time to time with a view to identifying basic causes as well as substandard conditions and practices, so that appropriate preventive measures can be put in place at both worker and management l e ve l s. Careful adherence to workplace safety protocols must remain an important consideration. Acknowledgements R. I. McDonald was supported by a scholarship from the Australian Dental Research Foundation Inc. The authors thank the Workers Compensation Board of Queensland and the Unive rsity of Queensland Occupational Health and Safety Unit for making available data for use in this study. References 1. Waddell CE, Bennett CL, Davies JL. Differences in the perceptions of HIV risk amongst dental care providers in Western Australian clinics. Aust Dent J 1994;39:233-7. 2. Felix DH, Bird AG, Anderson HG, Gore SM, Brettle RP, Wray D. Recent non-sterile inoculation injuries to dental professionals in the Lothian region of Scotland. Br Dent J 1994;176:180-4. 3. devries B, Cossart YE. Needlestick injury in medical students. Med J Aust 1994;160:398-400. 4. Beekmann SE, Henderson DK. Managing occupational risks in the dental office: HIV and the dental professional. J Am Dent Assoc 1994;125:847-52. 5. Udasin IG, Gochfeld M. Implications of the Occupational Safety and Health Administration s bloodborne pathogen standard for the occupational health professional. J Occup Med 1994;36:548-55. 6. Roy K, Bagg J, Follett EA. Occupational infection with hepatitis C virus in the healthcare setting. Dent Update 1994;21:100-2. 7. Reichart PA. AIDS and hepatitis: a problem for the dental team. Int Dent J 1994;44:49-54. 8. Epstein JB, Sherlock CH. Hepatitis C: rapid progress in medicine and implications for dentistry. J Can Dent Assoc 1994;60:323-9. 9. N ational Health and Medical Research Council/Australian National Council on AIDS. Infection control in the health care setting. Guidelines for the prevention of transmission of infectious diseases. April 1996. Canberra: Australian Gove rn m e n t Publishing Service, 1996:122-9. 10. Walsh LJ, Lange P, Savage NW. Problems encountered with the we a ring of protective gloves in general dental practice. Quintessence Int 1995;26:203-9. 11. Walsh LJ. Health and safety audit program. ADA (Qld) Newsletter 1995;394:18-22. 12. Stewart CM, Jones AC, Bates RE, Boeff D, Migliorati C, Bentrup K. Percutaneous and mucous membrane exposure protocol in a southeastern dental school. Oral Surg Oral Med Oral Pathol 1994;78:401-7. 13. Lange P, Savage NW, Walsh LJ. Utilization of personal protective equipment in general dental practice. Aust Dent J 1996 (in press). Address for correspondence/reprints: Dr L. J. Walsh, Dental School, The University of Queensland, Turbot Street, Brisbane, Queensland 4000, Australia. Australian Dental Journal 1997;42:2. 113