Odontology & Mass Disasters

--------------------------------------------------------------------------------

Mass disasters represent a significant challenge for dental personnel who are frequently called upon to provide identifications. Recently-published materials have highlighted the need to prepare such groups for the disaster challenge and report inadequacies in existing preparation methods with an emphasis on team integration, organisation and the psychological and emotional effects of such work. Many studies have retrospectively reported errors that have been made in disaster situations, but few have addressed the issues proactively. In an effort to provide a prepared team of dental members, a mock disaster exercise (Operation: DENT-ID) is conducted annually in Vancouver, Canada. This study analysed the effectiveness of this exercise in relation to team organisation, assessment of preparedness and the emotional and psychological issues. An index of preparedness was developed and described. This index, in the form of a questionnaire, can be given to participants in mock disasters to assess the effectiveness of such exercises. While the focus of this paper is on the assessment of dental personnel, the indices and methods used can be applied to any group working within the disaster team. Results indicate that the increase in preparedness as a result of the exercise was highly significant. This paper was written by David Webb, Iain Pretty and David Sweet.


--------------------------------------------------------------------------------

Home Page

--------------------------------------------------------------------------------


Introduction

Mass disasters represent one of the most challenging aspects of forensic dentistry. Many experts have called for mass disaster dental response teams to be prepared for the disaster challenge (1, 2). Authors report inadequacies in existing preparation methods with an emphasis on team integration, organisation, and the psychological and emotional effects of such work (3). Many studies have retrospectively reported errors that have been made in disaster situations, but few have addressed the issues proactively (3-8). This study addresses this hiatus in the literature. In order to provide a prepared team of dental members, a mock disaster exercise (Operation: DENT-ID) is conducted annually in Vancouver, Canada. This study analysed the effectiveness of this exercise in relation to team organisation, assessment of preparedness and the emotional and psychological issues.

Operation: DENT-ID

The training exercise was conducted over a one and one half day period, in association with the British Columbia Coroners Service and BC-FORT. The first afternoon was devoted to a lecture delivered by a guest speaker who had previously been involved in a mass disaster dental identification team. The following morning a mock mass disaster exercise was carried out. This was followed in the afternnon by extensive discussion and feedback. Twenty-nine dental personnel, each with varying degrees of disaster and identification experience, participated in the most recent exercise (April 1999). The group was split into three teams: antemortem, postmortem and comparison. Each team was organised by a team leader and a secondary leader. The team leaders, organisers and participants of the event are members of a provincial dental mass disaster response team.

The exercise simulated an airplane crash that required the identification of 10 individuals. Preserved human remains and antemortem dental records were available. Each of the teams processed their material as per a real disaster. Success was determined by the number of individuals identified at the end of the exercise. Each team was allocated a separate workspace and this was protected to ensure that "crossing the floor" (members of one group ‘crossing’ into the work space of another) was minimised. The role of each team was clearly defined.

The antemortem team was responsible for transcribing dental records received from dental practitioners on to standardised forms. The inherent problems of incomplete records, different tooth numbering systems and difficult-to-decipher notes were simulated. The postmortem team was responsible for the dental examination and charting of the found remains. Postmortem radiographs of the remains had been produced prior to the exercise and members of this group charted on to standardised forms. The production of postmortem radiographs was not included as part of the exercise as a portable x-ray unit was not available. Fragmented remains were included to replicate the condition of bodies likely to be encountered in a real disaster. The comparison team received the antemortem and postmortem standardised forms from the respective groups. Using laptop computers and the computer application WinID (Version 2; James McGivney, www.winid.com) possible matches were established and then the team compared the actual records to produce final conclusions. The use of computers to identify a relatively small number of remains was incorporated into the exercise to ensure that comparison team members were familiar with the operation of the system should its use be indicated in a larger disaster. Interaction between the groups was kept to a minimum and aspects of security and prevention of record "contamination" were all considered.

It was clear that the participation of all members in the afternoon feedback session was a crucial component of the exercise. Team leaders reported satisfaction with their team's performance and the success of the exercise.



Method

In order to determine accurately the success of the exercise several methods were employed. Data were collected during the mock scenario and immediately following the conclusion of the exercise. Collection methods included structured questionnaires and semi-structured interviews with key team members and participants. Observation of participants was carried out during the exercise to examine the team dynamics. This study assessed two main points: 1) team work within each of the three teams, and 2) preparedness of the whole group and individuals as assessed by a preparedness index.

Data were collected from the results of the questionnaires and analysed with information obtained from group observations and the semi-structured interviews. The interviews were conducted with the following individuals: a) each of the three team leaders, b) representatives from the Coroners service involved in the Provincial disaster plan and c) the guest speaker who had participated in a disaster involving a plane crash at sea.

Assessment of team work

The three teams were assessed using the Tuckman model for team performance (9). Within this model there are four terms used to describe a team’s development: forming, storming, norming and performing. Table I describes each of these identifiable stages. Figure I shows the questionnaire used to assess the team using this model. Figure 2 shows the preparedness index.

Assessment of preparedness

Preparedness was assessed using a preparedness index designed specifically for this study. Figure 2.

Results

The results of the study are shown in Tables II-IV. Table II contains the results of the team work assesment. It is important to note the closeness of the scores for the forming, norming and performing categories. Table III shows the preparedness score of each participant before and after the exercise. Table IV illustrates the mean differences in mean score for each assessed aspect of preparedness.

The interviews with the team leaders established the leaders' views on team performance and the overall success of the exericise. Interviews with other individuals related to the integration of the dental team into the larger mass disaster response and the realism of the simulated exercise. In total 26 correctly completed questionnaires were received from a total of 29 participants (90%).



Discussion
Team Development

The vast majority of the respondents in the three teams indicated that their teams had “performed” consistent with the expectations of the team leaders (Tuckman's fourth stage). See Table II. Equally, all respondents indicated that their teams were least like the volatile “storming” classification. Despite these apparently encouraging findings, caution must be exercised in relation to the closeness of the forming, norming and performing scores. The suggestion that this indicates no clear team perception is best explained by the ephemeral nature of the team itself (i.e. formed and disbanded during one day). The clearest team perception lay within the postmortem group, followed by the comparison group and then antemortem group. Interestingly, 7 out of 10 respondents within the postmortem group had not attended the previous year’s Operation: DENT-ID exercise and 3 of the 8 members of the comparison group had not. Only 1 out of 8 had not participated in the antemortem group. This result can be explained by the theory of “groupthink” where more cohesive groups (suggested by previous attendance and hence familiarity) are more concerned with achieving consensus than group decision making. Another factor is the unfamiliarity of participants with the antemortem process. Despite these concerns, all three teams demonstrated good group dynamics.




Preparedness

In terms of the efficacy of the exercise, (i.e. did the mock disaster increase the preparedness of the members?) a highly significant result was found. As part of the preparedness indices, 17 questions exploring both logistical and psychological preparedness were posed. As the index was issued before and after the exercise, it is possible to ascertain if participant preparedness changed as a result of attendance. With the exception of one participant, whose preparedness index remained unchanged, all participants indicated that their preparedness was greater after Operation: DENT-ID. See Table III. To test if this difference was statistically significant a paired samples t-test was employed (10). The highly significant result of t = -7.267, df = 25, p<0.001 was obtained. From this result we can conclude that there has been a highly significant increase in preparedness over the one and one half day exercise.

In order to highlight the benefit of this study further, it is important to assess the formative perspective (i.e. provide information on how the mock disaster exercise can be improved). This can be done without complicated statistical analysis, which is a strength of this user-friendly index. In order to identify areas of strength and weakness in the exercise each aspect of preparedness was isolated and compared. These results are shown in Table IV. In order to establish which aspects of preparedness could be improved, individual scores before and after the exercise were compared to see how much the mean scores changed. By doing this, the discrepancy of scores is restricted to a rating scale (i.e. between 1 and 4). By reviewing the data it is possible to elicit those aspects of preparedness that did not change significantly as a result of attending Operation: DENT-ID. The highest level of preparedness is a score of 4. It can be argued that any score of 3 or less should be examined, as this would tend to suggest a weakly-prepared aspect of the exercise.


Using these criteria the following areas of weakness were identified:
• Participants seem unprepared to leave offices and practices at short notice and for undetermined amounts of time

• Participants felt unaware of the psychological issues surrounding critical incident stress or post-traumatic stress disorder. They were not aware of the value of debriefing in order to address these issues. Participants also indicated that they would be unwilling to discuss the features of the disaster with their close family

• The exercise did not seem to provide sufficient information regarding primary literature pertaining to mass disasters

It is important to note that the preparedness index has not been validated. The index was developed by the authors based upon intuitive measures of preparedness for a mass disaster and the experience of one of the authors (DAW) with respect to psychological methods. Methods of validation for an index such as this are complex. The authors believe that the index represents a realistic measure. Further use of this index will confirm its validity in mass disaster assessment.

In summary the exercise should be regarded as a success. Team work was measured as effective and there was a highly significant increase in the preparedness of the participants as measured by the preparedness index. All interviews indicated a great deal of satisfaction with the exercise and with the abilities of those participating in it. The logistics of the exercise were smooth; a testament to the large volume of work that is required to stage such an exercise. The potential problems of this workload conflicting with dental practice responsibilities was illucidated during the team leaders' interviews.

The study identified areas of weakness that need to be addressed in order to increase the effectiveness of the exercise. One of the most pivotal areas of weakness was that of willingness to leave the workspace and support the identification effort. It can be argued that there is little point in training individuals who are ultimately not able to participate in an actual disaster. It appears that little can be done to address this point. During the exercise the importance of the identification team and the need to be available was emphasised repeatedly. Results of interviews highlighted that dentists were concerned about the financial implications of participating in a mass disaster. This area was addressed in the exercise but may need more reinforcement in the future. Those contemplating a similar program should be aware of this complication. A more radical solution is to select only those individuals who indicate their willingness to be involved prior to the exercise.

The second area of weakness pertained to the psychological issues. The preparedness data, in conjunction with interviews, showed that the participants felt that this area deserved more attention. The subject was covered in the exercise but the issue took second place to the larger implications of the exact duties of teams. Interviews with team leaders illicited differing opinions. One team leader felt that his responsibility was limited to the physical act of dental identifications and that other professionals should be responsible for the assessment of the mental well-being of his team members. Other opinions stated that the well-being of the group was of paramount importance to effective identifications and therefore was within their responsibilities as team leaders. All team leaders stated that more knowledge of the psychological issues would be useful. The issue of speaking to family members was raised specifically by the guest speaker who stated that involving those close around you was essential to ensure harmony both at the morgue and in the family environment. Interestingly, despite this, many of the participants did not feel that this is something that they felt prepared to do.

It is clear that more attention needs to be focused on the psychological aspects of mass disaster preparedness. The presence of actors exhibiting signs of post-traumatic stress disorder within teams and a psychologist trained in this area may help address this. The published literature on this subject is comprehensive and should be made available to the participants (11-19). Reference lists alone do not suffice. Certainly the psychological implications of mass casualty identification must be thoroughly addressed and this may be best achieved in small groups to enable open discussion. Interviews on this subject with participants recognised the value of the guest speaker whose candid and frank descriptions of the trauma of disaster involvement were highly valued.



Conclusions

A mock disaster can be a helpful tool in the training of dentists likely to be called to provide identification services in the event of mass casualties. Assessment of such exercises is essential to enable areas of strength and weakness to be identified and to assure authorities that the dental team is appropriately trained. Anecdotal evidence is helpful, but the use of properly structured questionnaires and interviews will enable accurate assessment. The authors encourage the use of mock disaster scenarios and of the measures provided in this paper to assess such exercises. The area of post-traumatic stress disorder must be carefully addressed, as well as the issue of commitment to the dental response team by the participant, including the financial impact that this may present.



Acknowledgements

The authors gratefully acknowledge Dr. Dave Hodges, Dr. Tom Routledge, Dr. Ian MacLachlan, and Coroners Chico Newell and Robert Stair for their assistance during this study. The authors extend their gratitude to Dr. Alan Hannam, Faculty of Dentistry, University of British Columbia for providing funding for this study. Dr. Iain A Pretty is supported by an educational grant from the Forensic Science Society (UK).



References

1. Morlang WM. Dentistry's vital role in disaster preparedness. J Calif Dent Assoc 1996;24(5):63-6.

2. Clark DH. An analysis of the value of forensic odontology in ten mass disasters. Int Dent J 1994;44(3):241-50.

3. Brannon RB, Kessler HP. Problems in mass disaster dental identification: a retrospective review. J Forensic Sci 1999;44(1):123-7.

4. Clark DH. The British experience in mass disaster dental identification. United Kingdom disasters. A historical review. Acta Med Leg Soc 1990;40:159-65.

5. Carpenter JP. Dental identification of plane crash victims. J N C Dent Soc 1968;51(1):9-12.

6. Harmeling BL, Schuh E, Humphreys HS. Dental identification of bodies in a major disaster. S C Dent J 1968;26(7):4-11.

7. Solheim T, van den Bos A. International disaster identification report. Investigative and dental aspects. Am J Forensic Med Pathol 1982;3(1):63-7.

8. Bell GL. Forensic odontology and mass disasters. N Y State Dent J 1989;55(3):25-7.

9. Tuckman B. Developmental sequence in small groups. Psych Bull 1965;63:384-99.

10. Bulman JS, Osborn JF. Statistics in dentistry. 1989, London: BDJ Books. Pages 34-9

11. Ursano RJ, Fullerton CS, Vance K, Kao TC. Post-traumatic stress disorder and identification in disaster workers. Am J Psychiatry 1999;156(3):353-9.

12. Turnbull G. Post-traumatic stress disorder. J R Soc Med 1999;92(3):152-3.

13. Simon RI. Chronic post-traumatic stress disorder: a review and checklist of factors influencing prognosis.
Harv Rev Psychiatry 1999;6(6):304-12.

14. Watts JR. Detecting people with PTSD following a disaster. Med J Aust 1994;160(5):312.

15. Laor N, Wolmer L, Wiener Z, Sharon O, Weizman R, Toren P, Ron S. Image vividness as a psychophysiological regulator in Post-traumatic stress disorder. J Clin Exp Neuropsychol 1999;21(1):39-48.

16. Guerin EJ. Air disaster and post-traumatic stress disorder. Am J Psychiatry 1999;156(8):1290-1.

17. Schutzwohl M, Maercker A. Effects of varying diagnostic criteria for post-traumatic stress disorder are endorsing the concept of partial PTSD. J Traum Str 1999;12(1):155-65

18. Butler DJ, Moffic HS, Turkal NW. Post-traumatic stress reactions following motor vehicle accidents. Am Fam Physician 1999;60(2):524-31.

19. Breslau N, Chilcoat HD, Kessler RC, Davis GC. Previous exposure to trauma and PTSD effects of subsequent trauma: results from the Detroit Area Survey of Trauma. Am J Psychiatry 1999;156(6):902-7.

Flesh Eating Beetles

FLESH-EATING BEETLES

Ugh!! Bugs!! Why are we talking about beetles? Because the Forensics Lab uses dermestid beetles to "skeletonize" birds and mammals.


"Skeletonize" means to clean the bones of birds and mammals. The Lab does this for two reasons: for bones that are submitted as evidence, and for bones that will become part of the Lab's standards collection. This standards collection is used by the scientists as reference material to identify the bones that are submitted to the Lab as evidence in wildlife law enforcement investigations.


What do Dermestids Eat?

Dermestids, or flesh-eating beetles (family Dermestidae) are akin to carpet beetles — they will infest and eat any dried organic matter: old books, furs, taxidermied mounts, woolens, carpets, artifacts of wood or feathers, etc. Therefore, the colony at the Lab is separated from other materials that they could destroy.


The beetles close-up. Credit: USFWS
How Are the Beetles Contained?

The Lab grows its colony of beetles in a large, custom-made plexiglas box with a tight- fitting screen lid. There are several chambers within this box to separate different types of bones. Cotton batting lines the bottom of the container, to give the larvae a burrowable substrate in which to pupate and to wick away any spilled water to help avoid fungal growth. Small bowls of water are placed within the container to raise the humidity and as a source of water for the beetles. Additional cotton or poly fill batting is put in each bowl to keep the beetles from drowning.

The bugs like it warm, moist and dark. To raise the humidity, the colony is covered with paper towels that are moistened daily. An additional benefit of covering the colony with moist paper towels is to simulate the skin of an animal, so that the colony lives in conditions that mimic its natural environment.

For extra protection, there is a perimeter ring of borax around the colony to help contain them. The borax scratches the beetles exoskeleton, and they quickly die.

Life Cycle

Let's look at their life cycle. It all begins when the adults lay eggs. The eggs hatch either in meat or close to it. These hatchlings are called larvae. The larvae go through at least six different molting stages or instars. After the last instar, the larvae become pupae and they burrow holes in the batting to pupate. They hatch as adults and thus begin the cycle all over again.

The Process of Skeletonizing

Before a carcass is put into the colony, it is frozen for 72 hours to prevent other insects from infecting the colony. And again, when the bugs' work is complete, everything that is left of the carcass is frozen to prevent any beetles from escaping and eating something else in the Lab.


Beetles skeletonizing a carcass. Credit: USFWS
Once a carcass has been given to the colony, it usually takes about a week to be skeletonized if the colony is active. What determines the activity level of the colony is how much food they have been receiving. The more food, the more active the colony will be.

When a carcass is put into the beetle bin, it must be closely monitored. The first thing that the beetles eat is the flesh. But, if left in with the colony, the beetles will continue on to the keratin (hair, nails and hoofs or horns) which can destroy the specimen. Once the bones are removed from the colony, they are frozen and then soaked in either soapy water or in ammonia water to retard mold. They are then air or sun dried thoroughly before being labeled and stored.


Beetles eating flesh. Credit: USFWS
The colony is used to process bones for both the standards collection and for evidence. When evidence is in the bug chamber, it is kept under lock and key, and only the Lab scientist that is working on that case has the keys. In this case, that scientist would be the one who does the daily tending of the colony. The Forensic Laboratory receives evidence about once a month that needs to be skeletonized. Examples of evidence that might need to be skeletonized are when 1) an elk pelvis needs to be identified as either male or female; 2) the trunk of a duck, with no head or feet and few feathers, needs to be identified as either a Teal or a Mallard; 3) a bear paw with skin and rotten meat needs to identified as either a grizzly or a black bear. In all of these cases, the scientist would compare the skeletonized bones of the evidence with the standards collection to make these identifications.

Who Else Has Beetle Colonies?

The Forensic Lab is not the only agency that has a dermestid beetle colony. Most museums maintain them. In addition, some schools with natural history departments and some zoos with educational departments will have a beetle colony.

The Lab's beetle colony was begun in 1989 and patterned after an existing colony at the Smithsonian Museum. Through the years, the Lab's colony has been used to spawn five or six new colonies at different facilities throughout the United States.

Incredibal Forensic Story

INCREDIBLE STORIES

"Royal Wool" of the Tibetan Antelope

The Forensics Lab, like any other crime lab, deals with many cases that we consider routine. For our analysts, identifying elk meat by its DNA, or a golden eagle feather by its appearance, or lifting a fingerprint from a gunstock, are all in a day’s work. But every year or two, we also face entirely novel challenges that require us to develop new techniques or new clues for species identification. One such challenge involved the exotic fabric called “shahtoosh.”



The hair of the Tibetan Antelope is so fine that a shawl of this fabric can be pulled through a man’s ring; thus, they are sometimes called “ring shawls.” Credit: USFWS


Shahtoosh is woven from the warm, dense underfur of the Tibetan antelope, or chiru (Pantholops hodgsonii). This graceful antelope inhabits one of the most forbidding environments on earth, the high, wind-swept Tibetan plateau. In the bitterly cold winters, chiru grow a wooly coat, which is shed in the spring. For generations, Himalayan weavers have gathered clumps of this shed wool — the finest produced by any mammal — and woven it into incredibly light-weight fabric shawls that were reserved for the use of royalty. Thus, the fabric was called shahtoosh, which means “royal wool.” Protected by the remoteness of their range, and by their speed and sharp eyes, Tibetan antelope populations were safe from human threats.



The Tibetan Antelope is protected by both the U.S. Endangered Species Act and at the highest level by the Convention on International Trade in Endangered Species (CITES). Credit: USFWS

All that changed with the Chinese occupation of Tibet, which brought roads and Kalashnikov rifles into the range of the chiru. Suddenly, whole herds could be run down with vehicles and slaughtered. Renowned conservationist George Schaller discovered that Tibetan antelope populations were crashing, and brought world attention to the connection between trade in shahtoosh and the plight of this unique species. The Tibetan antelope is now listed on the U.S. Endangered Species Act (ESA) and protected at the highest level by the Convention on International Trade in Endangered Species (CITES). All international trade in shahtoosh is prohibited. Tibetan antelope cannot be kept alive in captivity, and so the fabric comes only from animals which have been killed. Nevertheless, demand for this luxury fabric remains high, with shahtoosh shawls commanding prices of thousands of dollars apiece.

To enforce the ban on shahtoosh, it is of course necessary to be able to identify the fabric. When wildlife law enforcement seized shipments of shahtoosh shawls, these were invariably claimed to be “pashmina” or “shahmina,” legal fabrics woven from the wool of cashmere goats, often blended with silk. Microscopic comparisons of the fine underfur of the Tibetan antelope and the cashmere goat unfortunately revealed no clear diagnostic differences. The antelope hairs were slightly finer, but this difference was too subtle to be useful in the law enforcement context.



Microscopic examination of the Tibetan antelope guard hair shows a shaft filled with large, rounded cells. Credit: USFWS

At this point, Lab mammalogist and hair identification expert Bonnie Yates had an inspiration. What about the appearance of the outer “guard hairs,” she wondered. Since the fabric itself is woven from the underfur, the guard hairs from the animal’s outer coat were considered to be an undesirable contaminant and were typically ignored by fabric experts. With her biological perspective, Bonnie reasoned that these large guard hairs – always present in small amounts in any wool fabric – might reveal species-diagnostic characters missing in the finer underfur. Microscopic examination quickly proved her hunch to be correct. The shafts of Tibetan antelope guard hairs were completely filled with large, rounded cells. The shaft thus had the appearance of a clear tube filled with tightly-packed pebbles. The shaft of a cashmere goat guard hair, in contrast, was much smaller in diameter and had a dark, solid-appearing core which did not fill the shaft.




Lab mammalogist and hair identification expert Bonnie Yates discovered how to scientifically identify the Tibetan antelope hair. Credit: USFWS

Using these characters, Bonnie was able to prove that suspect shawls indeed contained the wool of the endangered Tibetan antelope, leading to successful prosecution of shahtoosh cases in the U.S., England, and Asia. Bonnie herself has traveled to Thailand to assist the Royal Thai Police in a major shahtoosh case, and to testify at a trial in Hong Kong where over a million dollars worth of shahtoosh shawls had been seized.

This is just one example of how Forensics Lab scientists combine their biological insight with laboratory techniques to expand the frontiers of wildlife forensics.

For detailed information on identifying shahtoosh shawls, please see the Lab publication Identification Guidelines for Shahtoosh and Pashmina (PDF 3,377 KB).

National Wildlife Forensics Lab

Examples of evidence items that are sent to us for examination:

blood samples (ideally, in a fresh or dried condition)
tissue samples (same as above, only include frozen)
whole carcasses (same as the above, except we're rarely that lucky)
bones
teeth
claws
talons
tusks
hair
hides
furs
feathers
leather goods (purses, shoes, boots...)
poisons
pesticides
stomach contents (uh huh)
projectiles (bullets, arrows...)
weapons (rifles, bows, traps....)
Asian medicinals (rhino horn pills, tiger bone juice...)
And pretty much anything else you might imagine that could have come from (or been made from) an animal.

Maggots Eating a Dead Cow

Rotting Human Decomp

Decomp Pig