An effort to standardize dental data records, including the results of dental treatments, is attracting attention as an effective method to help quickly identify bodies of victims in major disasters, in the wake of the Great East Japan Earthquake.
Because massive casualties are forecast in the event of the anticipated Nankai Trough earthquake, the government aims to establish a uniform national format for the records.
The standardization could also be utilized if Japanese fall victim to terrorist attacks or disasters overseas.
An adult has 32 permanent teeth. The proposed standard would convert the condition of each tooth into numerical data or codes using uniform rules and encode the information digitally.
This card, containing dental information used in Niigata Prefecture, shows various items, such as treatment methods, in easy-to-understand terms for experts.
For example, a tooth without cavity could be recorded as “1,” a filled tooth as “2,” a crowned tooth as “3” and a missing tooth as “4.”
The Yomiuri Shimbun last month asked Prof. Takafumi Aoki of Tohoku University to run search software using the proposed standardization method. Aoki was involved in confirming the identities of bodies after the Great East Japan Earthquake.
Aoki, an information engineering professor, demonstrated how the condition of teeth from a dead body could be input into a computer with 32 digits.
Aoki entered a series of numbers, “433134...,” and clicked the search command button. The computer cross-checked the data with dental records gathered from 1,000 living people that had been registered in the system’s database.
The software ranked the registered dental patterns in the database from No. 1 to 1,000, based on the extent of matching.
Aoki said, “The larger the number of unidentified victims, the more effective the system will be.”
In the worst-hit earthquake areas it was very difficult to identify bodies with few clues to their identities.
Dental data became a key focus as an effective method for confirming identities, because teeth change very little, even with the passage of time.
However, it was difficult to collect dental treatment records that could serve as base data of the victims while they were alive. The fact that local dental clinics had used differing formats to record dental information compounded this difficulty.
Recalling the experience, a local dentist said, “Making a random cross-check one by one just wasn’t realistic.”
The stress from the hard work took its toll on many dentists who felt physically and mentally ill.
This is what inspired a team of researchers led by Aoki to develop specialized software for this purpose two months after the disaster.
According to the Miyagi prefectural police, the search software narrowed down searches from around 500 unidentified victims to a much smaller number of possible matches. Police were able to combine the results from the dental software scan with results of DNA analysis and other techniques to accelerate the process.
After the disaster, Aoki’s team received inquiries from local governments in areas forecast to be hit hard by the envisaged Nankai Trough earthquake, including Shizuoka and Kochi prefectures. Tohoku University has distributed more than 100 sets of the software.
The Health, Labor and Welfare Ministry also became involved in the standardization plan, conducting experiments in Niigata Prefecture until March.
In the experiments, the accuracy of the scans was improved by increasing the number of options for describing the condition of teeth, and computer-score sheets were introduced to record the data.
The experiments treated data from 1,763 people as dental records from victims, removing the data for half of their teeth, as though those teeth had been destroyed or lost after death. The results gave the highest ranking to the correct records 87.5 percent of the time. The accuracy rate for the top 18 results was 99 percent.
The health ministry praised these results, with one official saying the system was able to “narrow down the results to correctly identify [a 'victim'] with great accuracy.”
The ministry plans to create a uniform nationwide format for the data so the system can be employed wherever a disaster occurs.
Hisako Saito, an associate professor of forensic medicine at Chiba University who is knowledgeable about methods used to identify people overseas, said the proposed method “will be useful to identify Japanese victims of disasters overseas.”
The health ministry will consider the possibility of linking the standardized data with similar databases in other countries in experiments planned later this fiscal year.
The government is interested in the disaster victim identification system used by Interpol. That system includes data on treatment using a code consisting of three letters.
Data organized using the Interpol method could be used as a global common language for this purpose.
Finland adopted such measures after some of its nationals went missing in the earthquake off Sumatra in 2004. Data standardized using Finland’s methods were converted to the Internet standard. By cross-checking the data with bodies found in the disaster-hit areas, authorities were able to identify 112 victims.
Citing these precedents, Saito said, “Japan should act quickly to standardize data across the nation.”
Many experts in the field point out that the standardization method will also be useful to identify foreign nationals who die in Japan.
Because the number of inbound foreign visitors is certain to rise as the 2020 Tokyo Olympics and Paralympics approach, it is possible that the proposed system will be put to use for a wider range of purposes.
Privacy concerns become roadblock to dental ID
Many experts believe that unless record-keeping is integrated into an envisioned government standardization plan, identifying victims in large-scale disasters will remain difficult.
Dental records are important for swiftly identifying disaster victims, but many dental clinics and records were destroyed in the Great East Japan Earthquake and ensuing tsunami in March 2011.
This prompted calls for a database where such records can be stored, but government ministries and agencies are cautious about establishing such a database.
The major bottleneck lies in the issue of privacy. The government is concerned that people will regard their dental records as privileged information.
Though the government has been proceeding with a project to standardize its record-keeping by gaining people's agreement, it is difficult to secure individuals’ consent in preparing the database.
A senior police official, who is in charge of identifying disaster victims, said, “The Health, Labor and Welfare Ministry should manage patients’ information gathered while they are alive.”
However, some health ministry officials said their job is to ensure people remain healthy, not collect data that could be used to identify dead people.
According to a 2012 government forecast, a massive earthquake in the Nankai Trough would, in the worst case, kill 320,000 people in Tokyo and 29 other prefectures.
“In preparation for the next large-scale disaster, we should discuss the standardization and creation of a dental database in an integrated manner, and swiftly introduce it,” said Prof. Toshinobu Komuro of Nihon University, who specializes in forensic medicine. He is a member of a ministry panel discussing how to standardize dental identification.
Wednesday 16 April 2014
http://the-japan-news.com/news/article/0001191496
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