By 1966 all fifty states had passed legislation regulating ...



The CSI Effect: Redefining Dentistry’s Role in Forensic Sciences

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Theresa S.Gonzales, DMD, MS and Duane R. Schafer, DDS, MS

“Wherever he steps, whatever he touches, whatever he leaves, even unconsciously, will serve as silent evidence against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen that he deposits or collects – all these and more bear mute witness against him. This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong; it cannot perjure itself; it cannot be wholly absent. Only its interpretation can err. Only human failure to find it, study and understand it can diminish its value.”

— Paul L. Kirk, PhD

“Father of Criminalistics”

Dr. Paul Kirk’s comments regarding the role of forensic science and evidence collection in law enforcement are the stuff of which popular television docudramas like CSI -- Miami are made. Each week millions of Americans tune in to this popular show in what appears to be nothing more than an national infatuation with a “21st-century whodunit" complete with the requisite scientific validation. This glorification of the use of scientific principles to assist in crime solving has produced what some legal analysts refer to as the “CSI Effect”. “As television educated America about the role of forensic evidence in the law enforcement/justice system, the legal community found itself adapting as juries began finding reasonable doubt when the State did not produce “sufficient” forensic evidence.  ‘The CSI Effect’ placed the legal community under a new burden of helping jury members distinguish the fictional aspects of television from reality.  Additionally, expert witnesses must now explore new ways of presenting testimony that captivates the jury’s desire to be not only entertained, but also convinced that law enforcement properly collected evidence and that crime scene technicians properly performed all of the relevant types of forensic analyses”.[i]

Our cultural fascination with the forensic sciences has allowed the public to potentially overestimate the dental as well as the medical professional’s capabilities and capacities with respect to our precise role in law enforcement. That role will be considered in detail in the pages that follow. Forensic odontology (often referred to as forensic dentistry) is but one of the many disciplines of forensic science and it is the one branch that requires unique dental expertise. The word forensics is derived from Latin word forensis and it literally means “public or forum”. A second meaning of the word is associated with “debate or argument". Generally, forensic odontology may be defined as that branch of forensic science that deals with the proper handling, examination and evaluation of dental evidence that is presented in the interest of justice.[ii] This article examines the role of dentistry and the dental health care team in the forensic arena. Forensic odontologists generally define their responsibilities along four main areas of concentration:

1) identification of human remains

2) recognition and responsible reporting of abuse

3) age determination

4) assessment of bite mark injuries

Each of these areas will be addressed in some detail in an effort to delineate the general scope of the practice of forensic odontology and applications of dental expertise to the forensic sciences.

Dental Identification:

The most common role of the forensic odontologist is the identification of human remains. It usually involves deaths with legal ramifications or multiple deaths in a mass disaster. It is hardly a new phenomenon. While earlier cases have been written about in France, the first documentation of a forensic identification utilizing dental evidence in the United States dates back to the late 1770’s. During the Battle of Bunker Hill, Major General Joseph Warren, a physician by trade, was struck in the back of the head with a musket-ball and fell dead instantly upon the hot and dusty field. The story goes that the general had been one of the very last to leave the redoubt. He had retreated about sixty yards to provide assistance to a wounded soldier when he was recognized by a British officer, who snatched a musket from a fellow soldier and shot him. His body was thrown in a ditch by the enemy and buried with others. When the British finally retreated from New England, the common grave site was discovered and his remains were identified by Paul Revere who recognized a prosthetic tooth he had made for Warren. Major General Warren was disinterred and honorably buried.[iii]

Today, the forensic odontologist will typically work as a consultant to the Medical Examiner or Coroner office. The authority to participate in the medicolegal investigation is granted by civil authority and covered under US Public Law 93-288 of the US Code. The importance of correct determination of a victim’s identity cannot be understated. Without a positive identification, prosecution of homicide cases, settlement of estates, collection of life insurance, and even remarriage of the surviving spouse may be impossible or at least delayed. Equally important is the end of grieving and coming to closure for the survivors associated with the remains.

There are many methods used in arriving at a positive identification for a set of remains. Some are considered presumptive and help build a case for a body’s identity, while others are definitive and will stand alone in the court of law. Among the findings that are considered presumptive are personal effects such as jewelry or clothing, tattoos, and visual identifications. These are scientifically unreliable, but can provide useful clues leading to identification. Visual identifications are fraught with potential error due to the emotional stress and subjective assessment of the family member or acquaintance. Numerous cases documenting misidentification based on visual identification alone, even of one’s own family member, fill the tabloids usually making front page headlines. In addition, remains burned beyond recognition, beheaded due to trauma or explosion, or the result of intentional disfiguring by a perpetrator during a crime, may make visual identification impossible. Dental identification, along with fingerprint analysis, and nuclear DNA testing are instruments or identification methods that have proven to be reliable for medicolegal purposes. Each of these three methods has their advantages and disadvantages.

Fingerprinting is a rapid computer aided, database driven science that can provide a positive identification, however it requires antemortem records and is limited by the destruction or decomposition of the body’s tissues. DNA analysis, while scientifically irrefutable is very technique sensitive and may not work in all situations. High heat, UV light and chemicals can make the recovery of genetic code impossible. Antemortem and postmortem dental evidence comparison is a rapid source for providing a positive identification that is completely unaffected by decomposition and often resistant to destruction. Enamel has been shown to withstand temperatures up to 16000 Fahrenheit and the orofacial musculature provides a significant protection even in cases of high velocity trauma. An additional advantage is the high statistical probability that can be established based on the unique individual characteristics assigned to the thirty-two teeth in the adult dentition. The only real disadvantage, like all the other methods, is the need for an antemortem reference. In reality, the strength of any identification is validated when all three methods are complementary.

Forensic identification by dental means is a team approach. The division of labor is normally split into three areas of concentration; postmortem examination and charting, antemortem record reconstruction, and evidence comparison. While numerous computer programs exist that will provide a reliable cross-referencing of data collected during the dental examinations and record reconstruction, a team comprised of at least two individuals is always recommended to provide confirmation of all findings.

Postmortem examination is an evidence gathering exercise requiring extreme diligence. Accessibility to the oral cavity is the first issue that needs to be addressed and the method used to obtain entrance is partly dependent on whether the remains are deemed to be viewable or non-viewable by the mortuary staff. In remains that are viewable, firm bilateral message of the facial musculature is often sufficient to break the body’s rigor and allow sufficient entry into the oral cavity to place a dental x-ray film or digital sensor. In cases where the opening is still limited, mechanical leverage may be required and resultant damage of the dentition is a concern. An easy but somewhat time consuming approach is to, after initial masseter muscle message, place two wooden tongue depressors in between the dentition on one side of the arch. Then continue to insert (often with the help of a mallet) additional tongue depressors between the original tongue blades. This method is very reliable and protects the dentition from damage. Once access is obtained a series of radiographs should be taken of all teeth and tooth-bearing areas in an effort to capture the dental evidence present as a graphic image and to aid in the documentation of a postmortem dental charting. Cleaning of the teeth and tooth-surfaces can be an aid to the dental radiologist and during the postmortem exam. Hydrogen peroxide applied by a soft bristle toothbrush will provide both chemical and mechanical cleaning action. One word of caution is to be gentle when manipulating or stretching the commissures of the lip, as a tear in this area is often difficult for the mortuary staff to moulage to the satisfaction of the surviving family members.

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Preparation of non-viewable remains for postmortem examination often requires surgical intervention to gain access to the dentition. Soft tissue access can be gained by full thickness longitudinal surgical incision starting at an access point through the maxillary philtrum and midline of the lower lip and continuing to the posterior along the depth of the buccal vestibules. Additional access to the ascending portion of the ramus is gained by continuing these incisions posteriorally and cutting through the mandible with a Stryker or other osteotomy-type saw. Once the opening is sufficient, radiographs and the postmortem dental exam can proceed in much the same way viewable remains are handled. Care should be taken with teeth that have been carbonized due to exposure to extreme heat; however gentle brushing with hydrogen peroxide, even in severe cases can uncover valuable dental clues.

The postmortem dental charting should be performed as a team with an examiner and a scribe. Once the entire dentition is charted the individuals should change roles and verify their findings. This is the best time to discuss variances in evidence interpretation. Common disputes include tooth numbering, actual tooth surfaces covered by a dental restoration, and pre- and post-traumatic injuries to the teeth. A remarks section is available on most forms to allow for comments regarding unique dental characteristics that would not be captured by a standard symbol. This is also a great time to take digital or conventional photographs of unique dental anatomy that may not be adequately captured on x-ray or pictures of the anterior jaw relationship that may be matched against family photos as these can prove invaluable.

The work of the antemortem reconstruction team begins with the fabrication of a believed-to-be list. This list could be as short as a single name or contain hundreds of possible victims when associated with a natural mass disaster, airplane crash or terrorist attack. In any situation a search for and/or eventual request for antemortem dental records ensues. The dental record is a legal document and is considered reliable evidentiary material if subpoenaed. All subjective and objective information concerning the patient contained within the record is considered in the reconstruction process. Upon receipt the team must merge the dental evidence captured on any dental radiographs with information garnered through the careful culling of the dental treatment record for written entries of work performed. The team must first validate the tooth numbering system used by the dentist and decipher any codes or abbreviations he or she may have employed in writing the operative reports. Problems can also exist with radiographs as one has to pay close attention to the correct orientation, especially on duplicate radiographs as the “raised dot” does not transfer. This antemortem detail can be an extremely tedious task and one where the team approach is critical.

Once postmortem and antemortem dental chartings are completed they are turned over to a comparison team whose goal is to establish points of concordance in sufficient number to arrive at a positive identification. There is no magic number as to how many points of concordance are necessary to make a positive identification as each case must be evaluated individually. To highlight this point, a single tooth match of a dental restoration captured on both antemortem and postmortem radiographs has proven to be sufficient in the courts to establish identity. However, when relying on charting comparisons alone, a minimum of twelve points of concordance with no mismatches is recommended.

The American Board of Forensic Odontology recommends 4 levels or degrees of certainty when arriving at an identification:

• POSITIVE IDENTIFICATION: Absolute scientific certainty

• POSSIBLE: Reasonable scientific certainty

• INSUFFICIENT: Insufficient information to make an identification

• EXCLUSION: Discordant information makes identification with absolute scientific certainty an impossibility

A final report documenting your findings along with your level of certainty is the last requirement. As with each step in this scientific process a review of the findings and co-signature should accompany this legal document.

Recognition and Responsible Reporting of Abuse

Maltreatment of children by their parents and /or primary caregivers has been with us for a long time. Family violence can be traced back to biblical times. Extreme parental punitiveness has been recognized a serious problem that demands intervention only relatively recently. While several court cases in the United States in the 19th-century dramatized the plight of abused children (largely through the actions of the Society for the Prevention of Cruelty to Animals- SPCA) and established legal and social precedents for intervention on behalf of maltreated children, widespread public recognition of child abuse did not occur until 1962. That year Dr.Henry Kempe published a landmark article entitled the “battered child syndrome” and drew national attention to the plight of abused children. Perhaps, no single publication has had such a profound effect on the welfare of children. Since that time, we have implemented a variety of concepts and laws to combat this societal problem. By 1966 all fifty states had passed legislation regulating child abuse, all of which mandated reporting. By 1986, every state but one required reporting of neglect, and forty-one states made explicit reference to reporting of emotional or psychological abuse. Initially, mandated reporting was limited to health care providers but this was eventually extended to include teachers, nurses, counselors, and the general public.

Child abuse as a social concept continues to evolve as children's rights are recognized by society. How we define “abuse” has a great impact upon our recognition of it. Child abuse is defined as the non-accidental, physical, emotional or sexual trauma; exploitation; or neglect that is endured by a child younger than 18 years of age while under the care of a responsible person, such as a parent, sibling, teacher or other person acting in loco parentis.[iv] There are approximately 3 million cases of child abuse reported annually in the United States. Two thousand to four thousand of the cases will result in death. As a practical point several nationally publicized child abuse/ child homicide cases have occurred in Texas over the past several years. The United States has high rates of reported childhood homicide and higher teenage suicide rates than most industrialized countries of the world. Childhood homicide rates have more than doubled over the past 25 years, and there is no indication that this trend is abating. Since, so many cases of abuse culminate in a fatality, it is important to recognize the clinical indicators of abuse.

Oral aspects of child neglect and abuse are well-known to the dental health care team. The Prevent Abuse and Neglect through Dental Awareness (PANDA) coalitions have trained thousands of dentists and auxiliaries in the recognition and reporting of such injuries. Craniofacial injuries occur in more than 50% of the cases of child abuse. Often these are unexplained injuries that are inappropriately reported by the caregiver or the presentation is inconsistent with the history provided. Other characteristics of orofacial injury in child abuse relates to the multiplicity and repetitive nature of the injuries. These injuries often appear in various stages of resolution. The face and the oral cavity in particular are frequent targets of abuse. Easy access to the child's head as well as the oral cavity’s role in communication and nutrition make it particularly susceptible to abuse. Not surprisingly, the oral cavity is a frequent site of sexual abuse in children and oral gonorrhea in prepubertal children is pathognomonic of sexual abuse. Abusive trauma to the face and mouth include all the following:

• Laceration of the labial or lingual frenum- resulting from either being forcefully struck or forced feeding.

• Repeated fractures or avulsions of the anterior teeth.

• Facial bone and nasal fractures.

• Bilateral contusions of the commissures of the lips.

• Soft and hard palate ecchymosis/petechiae

Since many abusive appearing injuries can also occur accidentally, a detailed history of the event should be sought. Parents attempting to conceal abuse often provide discrepant histories as to the nature of the presentation. Anytime a discrepant history is given by a parent or caregiver abuse must be suspected. Delay in obtaining medical and dental care, although not pathognomonic for abuse, should arouse suspicion. A past medical history of other unexplained or inadequately explained injuries should mandate a thorough review of other emergency department and inpatient medical records. There are however, some clinical findings that are virtually pathognomonic of abuse including patterned loop marks, adult human bite marks, immersion burns and metaphyseal bone fractures often labeled as “bucket handle fractures”. Non-organic failure to thrive is characteristic of parental deprivation/child neglect.[v]

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Each week, there are reports in the local and national news of children who are injured or murdered by adults charged with their well being. Often these sensationalized stories are met with public outrage and force us to grapple with the question of why some parents intentionally harm their children. No doubt, parenting is a demanding, challenging, and often physically exhausting job that taxes even the most capable person. For example, when a maternal or paternal characteristic such as poor impulse control is coupled with a toddler whose developmental goal is independence, the risk for abuse is great. Children represent our most valuable resource. Studies have shown that abuse occurs at all socioeconomic levels and when it comes to damage, there is no real difference between physical, sexual and/or emotional abuse. All that distinguishes one from the other is the abuser’s choice of weapons. In 2001, a report released from Prevent Child Abuse America estimated that the United States spends $258 million each day as a direct or indirect result of the abuse and neglect of our nation's children. Since conservative estimates were used, the actual annual cost could be higher than its estimate of $94 billion per year. This estimate includes the costs associated with intervening to help and treating the medical and emotional problems suffered by abused and neglected children, as well as the cost associated with the long-term consequences of abuse and neglect to both the individual and society at large.

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Mandated reporters are bound legally and ethically to have their reporting threshold activated when they have a “reason to suspect” that abuse has been committed. State reporting laws do not require mandated reporters to be convinced that child abuse or neglect has transpired in order to make the report. Physicians, dentists and other mandated reporters are required to submit a report if they have “ reasonable cause to suspect”, “ cause to suspect” or “ cause to believe”, that a child has been abused or maltreated. Mandated reporters are protected from civil and criminal liability for unsubstantiated reports if the reports were “made in good faith”. The etiology of child abuse is complex and the profile of the abuser or is varied. In spite of these limitations, we need to consider abuse as a symptom of family dysfunction. If a parent feels as though he or she has abusive tendencies, they should be encouraged to voluntarily seek help from community advocacy programs. Educational programs to promote positive parenting are extremely beneficial to society at large.

Abuse represents a spectrum of behavior. It is repetitive in nature and fatal abuse is often preceded by minor manifestations of maltreatment, which might be overlooked by physicians, dentists, teachers, social workers and others who are in frequent contact with the child. The sad truth is that child abuse kills more children in the United States each year than do accidental falls, drowning, choking on food, suffocation and fires in the home combined. Children should never die because of our inability to confront the possibility of abuse. Healthcare providers must identify children at risk, educate the families we serve and report suspected cases of abuse and neglect to the appropriate authorities. Our lack of understanding of the complex etiology of child abuse does not absolve our collective responsibility to protect those individuals at risk. As Dr. Henry Kempe so eloquently stated almost 34 years ago, “It is just not possible to worry about all of the children all of the time. There lies the frustration and total inaction as well. For each of us there must be only one child at a time …”[vi]

To raise awareness about the impact of child maltreatment and its prevention, the blue ribbon campaign is held each year during the month of April, Child Abuse Prevention Month. Throughout the month, the community is encouraged to wear a blue ribbon to symbolize their commitment to protect children and end child abuse and neglect. Anyone in the United States may make an anonymous report of abuse, neglect or sexual abuse by reporting it to the emergency services by dialing 911 or calling the local police department. Abuse and neglect may only be reported at the state or local level, not to the U.S. government. Most states have a toll-free hotline staffed by trained call screeners. When contacted, they will either open the case for investigation or log the report. Depending on available resources and the department's legal mandate, one report may not be sufficient to open a case, but a detailed report about a potentially serious case, or multiple reports (by different reporters), may suffice. At that point, someone from a legally designated agency will investigate the report. The investigators may determine there is no evidence of maltreatment, that there is evidence enough to offer support to the family in the home, or that there is evidence enough to remove the child from the home. The National Child Abuse Hotline (1-800-4-A-Child) is another resource for citizens wishing to report abuse. Hotline counselors provide local reporting information and will stay on the phone while a three-way call is placed to local authorities. In Texas cases of suspected abuse can by made by calling the state hotline @ (800-252-5400) or by accessing the following website: .[vii] The following reporting protocol is specific for the State of Texas.

Statewide Abuse, Neglect and Exploitation Reporting System

This reporting system is provided for your convenience to report instances of abuse or neglect that do not require an emergency response. An emergency is a situation where a child or elderly/disabled person appears to face an immediate risk of abuse or neglect that could result in death or serious harm.

Call your local law enforcement agency or 911 if the situation is an emergency.

If this is an emergency and you are deaf and equipped with TTY, you may call Relay Texas by dialing 711 or 1-800-735-2989. The caller uses a TTY to type conversations to a relay agent who then reads the typed conversation to a hearing person. The relay agent transmits the hearing person's spoken words by typing them back to the TTY user. Statewide Intake's phone number is 1-800-252-5400.

Call Statewide Intake at 1-800-252-5400 if

• the situation you are reporting is an emergency;

• you prefer to remain anonymous;

• you have insufficient data to complete the required information on the report; or

• you do not want e-mail confirmation of your report.

I have read the notice above and I believe that the instance of abuse or neglect I have to report is NOT an emergency.

NOTE: Clicking on the above link will download the appropriate forms for reporting and the report can be submitted online.

Physical abuse as well as neglect of elders should also be recognized and responsibly reported to the appropriate authorities. In Texas, during 2004, Adult Protective Services completed 61,342 investigations of abuse, neglect, or exploitation involving vulnerable adults. Of these, 44,694 were confirmed. A vulnerable adult is defined as a person who is being mistreated or is in danger of mistreatment and who, due to age and/or disability, is unable to protect himself or herself. The Adult Protective Services agency — a component of human service agencies in most states — is typically responsible for investigating reports of domestic elder abuse and providing families with help and guidance. Visit the National Center on Elder Abuse ()[viii] for data, fact sheets, and other information on elder abuse, neglect, and exploitation in the United States. Listed below are the toll free numbers for reporting vulnerable adult abuse.

• Elder Abuse: Domestic/Community

1-800-252-5400 or (512) 834-3784

• Nursing Home Abuse/Long Term Care

1-800-458-9858

• Abuse in Hospitals, Psychiatric Hospitals, and Other Medical Facilities

1-888-973-0222

• Abuse of Persons Receiving Mental Health/Mental Retardation Services

1-800-647-7418

• Domestic Violence Hotline

1-800-799-SAFE or 1-800-799-7233

Age Determination

Forensic odontology and forensic anthropology work in concert for verification of age. Interest in determining age of living persons, notably for adolescents for whom no birth records are available, has a long history. In ancient Rome, adolescents were considered fit for military service as soon as their second molars had fully emerged. A historical precedent for the use of tooth development as an indicator of chronologic age has been handed down from 19th century England. English legislation at the time stipulated that children under age seven were not punishable for crimes they committed – how Dickensian (Oliver Twist). In present day applications, age calculation is necessary for determining the age at the time of death in order to narrow the search for unknown persons but it can be useful among the living to differentiate the juvenile from the adult status in criminal law cases. Dental Development is arguably the most accurate index for age determination from before birth until the early teens.[ix] In most American jurisdictions at age 18, a juvenile becomes an adult and the legal implications change dramatically. Moreover, it may be necessary for chronological age estimation in relation to school attendance, social benefits, employment and marriage. Age is determined by studying a number of skeletal features, principally the skull, teeth and centers of ossification. Forensic anthropologists using a number of validated anthropomorphic measurement tables have established normative values for age determination using the pubic symphysis, articular surface morphology, dental attrition, epiphyseal closure, and bone growth and development in specific populations.[x] Determination of dental age-using stages of tooth development to gauge an individual's degree of maturity is one of a few biologic methods for monitoring physiologic development, and the dentition arguably is the only system available from prior to birth to early childhood. Dental development provides some of the best evidence for determining the age of death in children. The most widely used standard is one familiar to dentists: the Schour and Massler/Ubelaker chart.[xi] A version of it is available from the American Dental Association.

Primary Teeth Eruption Chart [xii]

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Permanent Teeth Eruption Chart [xiii]

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The Sequence of the Formation of the Human Dentition (Schour and Massler, 1941) [xiv]

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The age of this subadult patient can be estimated by comparison of this panoramic radiograph with the Schour and Massler eruption sequence chart displayed above. (The known chronological age of this child was 8 years 3 months.)

During the period of growth and development, age estimation is usually quite precise; however, with the cessation of growth and eruption of the permanent dentition, assessment of age becomes more difficult, relying principally on evidence of degenerative processes. [xv]Age estimates are based on the age of eruption of the deciduous and permanent dentition. Teeth begin to mineralize from the cusp tips or incisal edge of the crown and increase in length until the root is complete and the apex closes.[xvi] The first deciduous tooth begins to mineralize in the middle trimester and third molar mineralization is complete during or after late adolescence. This method is useful in age estimates of up to about 15 years. The third molar (wisdom tooth) erupts after this time, but is so variable in age of eruption, if it erupts at all, that it is not a very reliable age indicator. The American Board of Forensic Odontology (AFBO) conducted a “third molar study”- to determine the accuracy of estimating chronological age from the developmental status of third molars as viewed radiographically. The study design involved 823 cases. The volunteer subjects were between the ages of 14.1 years and 24.9 years of age. Age assessment was performed by recognized diplomats of the AFBO using the scheme devised by Demirjian and coworkers. The conclusions of their study are summarized below: [xvii]

• The stage of third molar development is an inaccurate predictor of chronologic age.

• At any stage of development, a range of about 8 years is necessary to be certain that 95% of individuals are included in the estimate.

• Third molars develop earlier in males than in females.

• The stage of third molar tooth development varies between maxilla and mandible and between left and right.

• If the third molar crowns are less than half complete (stages A, B, and C) –it is virtually certain that the subject is less than 14 years old.

• If the maxillary third molar root formation is complete with closed apices (stage H) and the subject is male – 85% degree of certainty that he is at least 18 years of age.

• If the maxillary third molar root formation is complete with closed apices (stage H) and the subject is female – 90 % degree of certainty that she is at least 18 years of age.

• If the mandibular third molar root formation is complete with closed apices (Stage H) and the subject is male, one can be about 90% certain that the individual is at least 18 years of age

• If the mandibular third molar root formation is complete with closed apices (Stage H) and the subject is female, one can be about 92% certain that the individual is at least 18 years of age.

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THIRD MOLAR ASSESSMENT Adapted from Mincer, et al, “The ABFO Study of Third Molar Development and Its Use As an Estimator of Chronological Age,” Journal of Forensic Sciences, Vol. 38, No. 2, March 1993, pp. 379-390.

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Using the degree of third molar calcification estimate the age of this Caucasian female. (the known chronological age is 16 years 1 month.

All growth processes slow down over time, so that the parameters become less accurate as the reach their definitive dimensions. After age 25, almost all attempts at established macroscopic methods for age estimation in the human skeleton are problematic. High inter-individual variability results in error margins that may reach 7 years, at best, for ages after skeletal growth is complete. The reliability of using third molar development to determine juvenile versus adult status is controversial and other modes of age determination including anthropological data must be incorporated. In short, the accuracy of current age determination methods (e.g. chronology of dental eruption or fusion of the epiphyses at different skeletal sites) decrease with age and are of limited usefulness beyond the age of skeletal maturity (25yrs).[xviii] Recently, there have been research efforts directed at biochemical assays and analysis of various proteins to further define the aging process in the mature human skeleton.

Assessment of Bitemark Injuries

Bite mark evidence gain national attention in 1978 when this physical evidence connected serial killer Ted Bundy to the murders committed at the Chi Omega sorority house at Tallahassee’s Florida State University. Lisa Levy was dead but on her buttock Ted Bundy had left a piece of evidence which could be used to link him to the crime and put an end to his crime spree which probably began as early as 1973. During Bundy’s reign of terror which spanned from the Pacific-Northwest to Florida more than two dozen girls were brutally beaten, raped and murdered. This was the first case in the legal history of Florida that was prosecuted on bite mark testimony and the first time physical evidence linked Bundy to one of his crimes.[xix] Conversely, in a regrettable miscarriage of justice, bite mark testimony was the only physical evidence that connected Ray Krone to the stabbing death of Phoenix cocktail waitress Kim Alcona. The prosecution’s forensic odontologist convinced the jury of the scientific certainty of the bite mark evidence. Ray Krone always maintained his innocence and he was eventually exonerated when DNA on the victim’s clothing was matched to another individual who was currently incarcerated in the penitentiary on an unrelated sex crime. Ray Krone served ten years in prison in Yuma, Arizona and two of those years were spent on death row before his conviction was overturned. There is no doubt that bite mark evidence is useful physical evidence that is legally accepted and admissible in a court of law. However, great care must be taken in evidence collection and in the expression of scientific certainty regarding bite marks as they are considered hard evidence and are highly persuasive to juries who weigh the evidence.[xx]

Bite injuries are relatively common and are seen in a variety of circumstances including assaults, rape, murder and child abuse. The marks left on the skin may be of evidentiary value in identifying the biter or in eliminating from suspicion those suspected of making the bite mark. Common areas where bite marks may be found include the arms, neck, breasts, trunk, cheeks and legs. Forensic odontologists develop the skill of comparing dental impressions taken from a person's mouth to bite-mark impressions on the skin of a victim. They can also analyze bite marks on food or other inanimate objects in cases where a perpetrator might have bitten something in the victim's home and left it behind at the crime scene.   What experts seek are a sufficient number of points of similarity between the evidence and a suspect to be able to say with a reasonable degree of certainty that this is the perpetrator. The physical characteristics of both the bite mark wound and the suspect's teeth include:

• the distance from canine to canine

• the shape of the mouth arch

• the evidence of a tooth out of alignment

• teeth width and thickness, spacing between teeth

• missing teeth

• the curves of biting edges

• unique dentistry

• wear patterns such as chips or grinding. 

All of these are examined in detail and than compared, preferably in a blind test in which the odontologist is not aware of which teeth impressions belong to the suspect.  At the very least, the injury pattern itself should be completely analyzed first before looking at the data from the suspect. Most bite marks are found in the following type of violent crimes: (1) the homicide victim involved in sexual activity around the time of death; and (2) the battered-child homicide victim.  Battered children have randomly placed bite marks that are generally diffuse and of poor detail.

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In 1984, the American Board of Forensic Odontology established Guidelines for Bite Mark Analysis in an effort to standardize techniques for recovery, storage, analysis and evaluation of bite mark evidence. These guidelines have been updated at regular intervals to reflect refinements in evidence collection and appropriate applications of prevailing technologies. Since the biting process is dynamic and human skin is a poor recording medium, rigorous scientific discipline must be exercised in bite-mark analysis. The evidentiary value of the physical evidence of this type of patterned injury is directly proportional to the clarity of the bite mark. Poor quality bite marks have negligible evidentiary value in legal proceedings. If salivary amylase can be recovered from the bite mark, then ABO blood group classification and DNA analysis from salivary trace evidence will be attempted. As with all physical evidence, an objective approach to evaluation combined with legitimate expressions of scientific certainty are imperative in an effort to render a valid expert opinion. Bite mark analysis along with the foundational arguments for the individuality of human teeth continue to receive challenges related to the rules of scientific admissibility and reliability with respect to court proceedings. Standardization of techniques and meticulous attention to detail along with continued research in this area should help to minimize the ongoing legal challenges to this physical evidence regarding scientific validity.

How to Get Involved

No doubt, the legal community will continue to rely on the dental profession to provide expertise in civil and criminal proceedings. Regrettably, undergraduate and most graduate dental school curricula do not provide appropriate levels of training in forensic applications of dental science. Education, experience and membership in professional organizations are necessary to ensure that dentists and dentistry remain committed to the scientific basis of the forensic sciences and in order for forensic odontology to continue to meet the standards of judicial review. In order to assist the lower courts in applying Daubert, the Court provided the following list of factors that courts should consider before ruling on the admissibility of scientific evidence:

1. Whether the theory or technique has been reliably tested;

2. Whether the theory or technique has been subject to peer review and publication;

3. What is the known or potential rate of error of the method used; and

4. Whether the theory or method has been generally accepted by the scientific community.

In assessing admissibility under the Daubert standards, courts are seeking a better understanding of the scientific bases of forensic analysis. Courts are increasingly questioning the standards to which the experts rendering the opinion are held. Paralleling the heightened public expectation of forensic science capabilities is the growing national trend to find expert witnesses liable for malpractice. According to Dr. Michael Bowers, “the advent of expert malpractice suits has overcome the common law assumption of judicial immunity, limited immunity or testimonial privilege provided to expert witnesses”.[xxi] Since the expert witness will continue to come under increasing legal scrutiny, it is imperative to render only scientifically validated opinions that can stand up to independent review. Never let your enthusiasm for the case cloud your professional judgment and compromise the “expert” quotient. This field of forensic odontology encompasses many scientific areas which, if used properly, can make invaluable contributions to the resolution of social and legal disputes. If you have an interest in this branch of the forensic sciences, there are a number of ways to get involved. The simplest way is to talk to your local dental society to identify opportunities for participation in your area and potential mentors willing to help you acquire the skills necessary for effective participation. Listed below are a number of resources that you may find useful as you develop or refine your interest in forensic odontology.

Training in Forensic Odontology

Armed Forces Institute of Pathology

202-782-2100

Washington, D.C.



University of Texas - Southwest Symposium on Forensic Dentistry

Health Science Center

San Antonio, TX

210-567-3177



The Council on Dental Practice of the ADA sponsors frequent training programs and

conferences on basic dental forensic topics and techniques. Call the Council at 1-312-

440-2895.

DMORT



Professional Societies

American Society of Forensic Odontology



The Manual of Forensic Odontology produced by the ASFO is available at the site for

purchase. Member price $53. Non-member price $79.

American Board of Forensic Odontology



The Diplomate’s Manual produced by the ABFO is available at the site for free

downloading.

American Academy of Forensic Science



The opinions expressed here are the private views of the authors; they should not be construed to represent the official position or policy of the United States Army, the United States Navy or the Department of Defense.

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References

[i] Botluk,D. , Mitchell B. Getting a Grip on the 'CSI Effect': The National Clearinghouse for Science, Technology and the Law at Stetson University College of Law,

[ii] Bowers, C. Michael Forensic Dental Evidence. San Diego, CA: Elsevier Academic

Press; 2004. ISBN: 0-1212-1042-1

[iii] Paton, J. The Men Behind the American Revolution: General Joseph Warren

[iv] Herschaft, EE. Forensic Dentistry, Oral and Maxillofacial Pathology, 2nd ed. .Philadelphia, W.B. Saunders Company, 2002.

4 Stmger RG, Bross DC, eds. Clinical Management of Child Abuse and Neglect: A Guide for the Dental Professional. Chicago, IL: Quintessence Publishing Co, Inc; 1984

Ludwig S, Corner AE, EDS. Child Abuse A Medical Reference 2nd ed New York, Churchill Livingston Publishing, 1992.

5 Kempe. CH Silverman, FN., Steele, BF, Droegenmueller, W, Silver, HK. HK. The Battered Child Syndrome. JAMA, 181, 17-24.

6

[v]

[vi]Gustafson G. Age determination on teeth. Journal of the American Dental Association 1950 (41), pp. 45-54.

[vii] Fixott, Richard H., ed. The Dental Clinics of North America, Forensic Odontology, Philadelphia, PA, Volume 45 Number 2 April 2001.

Stimson, Paul G. and Mertz, Curtis A. editors. Forensic Dentistry. New York: CRC

Press; 1997.

[viii] Massler and Schour. The Appositional Life Span of the Enamel and Dentine Forming Cells J Dent Research, 1946, 25, pp145

[ix] (

[x] (

12 Massler and Schour. The Appositional Life Span of the Enamel and Dentine Forming Cells J Dent Research, 1946, 25, pp145

[xi] Johanson G. Age determination from human teeth: A critical evaluation with special consideration of changes after fourteen years of age, Odontologic Revy 1977, 22 (Suppl. 21), 1-126.

14 Moorrees, Fanning, Hunt. Age Variation of Formation of Ten Permanent Teeth

J Dent Research, 1963, 42, No6, pp1490-1502

15 THIRD MOLAR ASSESSMENT Adapted from Mincer, et al, “The ABFO Study of Third Molar Development and Its Use As an Estimator of Chronological Age,” Journal of Forensic Sciences, Vol. 38, No. 2, March 1993, pp. 379-390.

16 Kashyap V.K., Koteswara Rao N.R. A modified Gustafson method of age estimation from teeth. Forensic Science International 1990 (47), 237-247.

17 Asku M N, Gobetti J P. The past and present legal weight of bite marks as evidence. Amer J Forensic Med and Path 1996; 17: 136-140.

18 /killers/bundy.html

19

21 Bowers, CM. Jurisprudence Issues in Forensic Odontology, The Dental Clinics of North America-Forensic Odontology. Volume 45, No.2, W.B. Saunders Company, April 2001, p. 413.

Additional References:

Bowers MC, Bell GL: Manual of Forensic Odontology, ed 3, Ontario, Canada, Manticore Publishers, American Society of Forensic Odontology, 1997.

Fixott, RH. The Dental Clinics of North America (Forensic Odontology), Volume 45, No.2, W.B. Saunders Company, April 2001.

Sweet DJ: Bitemark evidence. In Bowers CM, Bell GL (eds): Manual of Forensic Odontology, ed3. Colorado Springs, CO, ASFO, 1995.

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This pattern of injuries including multiple contusions in various stages of resolution combined with the discrepant history provided by the caregiver is characteristic of abuse.

A delay in seeking medical attention for this child’s ruptured ear drum combined with demonstrable contusions suggests physical abuse. This child was well known to child protective services.

Bite marks should be suspected when ecchymoses, abrasions or lacerations are found in an elliptical or ovoid pattern. This pattern of injury raised serious questions regarding this putative “crib death”. An intercanine distance measuring more than 3.0 cm is suspicious for an adult human bite even though this bite mark had no evidentiary value.

The methodical placement of additional tongue blades can maximize interincisal opening and minimize post mortem orofacial trauma.

Dental Development is arguably the most accurate index for age determination from before birth until the early teens.

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