ABFO Bitemark Methodology Guidelines

            Methods to Preserve Bitemark Evidence

            Methods of Comparing Bitemark Evidence

    ABFO Standards for Bitemark Analytical Methods

    ABFO Bitemark Analysis Guidelines

    ABFO Bitemark Terminology Guidelines

            Terms Used to Describe and Interpret Bitemarks

            Ordinate Ranking of Terms: Certainty That Injury is a Bitemark

            Ordinate Ranking of Terms: Certainty of Link Between Dentition and Bitemark

    ABFO Standards Regarding Bitemark Terminology

    ABFO Bitemark Forensic Report Writing Guidelines   

In 1993, the ABFO Bitemark Workshop #2 Committee distributed a questionnaire on Bitemark methodology. About half of our members responded to the Bitemark Methodology survey reviewed at the three day Bitemark Workshop in San Antonio on February 12-14, 1994. The methods used by those that responded to collect and analyze Bitemark evidence were presented. This project is an update of the efforts begun in the 1984 Bitemark workshop. This set of guidelines is not intended to invalidate the document generated as a result of the 1984 workshop.

Please read Bitemark Methodology with the following perspective:

There is a need for forensic dentists to agree on basic methodology used in bitemark cases so as to maximize the quality, completeness and validity of the collection and analysis of bitemark evidence. It is not expected that this document is ideal to all forensic dentists. However, it represents majority opinions and has the highest level of acceptance to the largest number of odontologists. All Diplomates (and other forensic odontologists) will have to make some compromises if the science of forensic odontology is to achieve the higher objective of universally agreeable methodology. There is no intention for the ABFO to mandate methods but instead to provide a list of generally accepted valid methods for this point in the development of our science. This document is not meant to stifle the development of new valid techniques that meet the criteria of the scientific method. There is every intention for the ABFO, as a credible body of experts, to present a clear and unified message as to what its members use and accept as valid methods for the collection and analysis of bitemark evidence. This document will present methods that have been agreed upon and approved as valid preservation and analysis procedures. In keeping with the commitment not to stifle the development of new methods, individuals should continue to develop new and possibly better techniques. These new techniques should be backed up by the use of accepted techniques and should satisfy the basic concepts of the scientific method.

1. Bite Site Evidence

General Considerations - It should be recognized that often the Forensic Odontologist is not involved in the initial examination and collection of the Bitemark evidence. This does not necessarily preclude the ability of the Forensic Odontologist to render a valid opinion. The below listed methods are not meant to be an all encompassing list of preservation methods; however, it does list those methods that are used by the Diplomates of the ABFO. The use of other methods of documenting the Bitemark evidence should be in addition to these techniques.

    A. Saliva Swabs of Bite Site

• Saliva swabbings of the bite site should be obtained whenever possible. Obviously, certain circumstances may preclude the collection of this evidence. If the region had been washed prior to the opportunity to swab this procedure would not be possible. If swabbing the area would damage or alter the pattern, it should either not be done or accomplished only after all other preservation methods have been employed.

• It is acceptable to use either cotton tip applicators or cigarette paper to gather this evi- dence. Other appropriate mediums may be used to collect this information.

• Control swabbings should be taken from other regions or portions of the object or in- dividual that was bitten.

    B. Photographic Documentation of the Bite Site

• The bite site should be photographed using conventional photography and following the guidelines as described in the ABFO Bitemark Analysis Guidelines.

• The actual photographic procedures should be performed by the forensic dentist or under the odontologist's direction to insure accurate and complete documentation of the bite site.

• Color print or slide film and black and white film should be used whenever possible.

• Color or specialty filters may be used to record the bite site in addition to unfiltered photographs.

• Alternative methods of illumination may be used.

• Video/ digital imaging may be used in addition to conventional photography.

• A tripod, focusing rail, bellows or other devices may be utilized.

        1. Lighting

• Off angle lighting using a point flash is the most common form of lighting and should be utilized whenever possible.

• A light source perpendicular to the bite site can be utilized in addition to off angle lighting; however, care should be taken to prevent light reflection from obliterating mark details in photograph due to "wash out" due to light reflection.

• A light source parallel to the bite site can be utilized in addition to off angle lighting.

• A ring flash, natural light and/or overhead diffuse lighting can be utilized to off angle lighting.

         2. Scale

• An ABFO No. 2 scale should be utilized whenever possible.

• The placement of the scale should follow the guidelines as established in the ABFO Bitemark Analysis Guidelines.

    C. Impressions of Bite Site

        1. Victim's Dental Impressions

• When the bite site is accessible to the victim's dentition impressions of the victim's teeth should be obtained.

• Would be useful if victim had bitten the assailant.

        2. Impressions of the Bite Site

• Impressions of the bite site should be taken when indicated according to the ABFO Bitemark Analysis Guidelines.

• A backing material should be used to maintain the contour of the impression site.

    D. Tissue Specimens

        1. General Considerations

• The bite site should be preserved when indicated following proper stabilization prior to removal.

• The resection of the tissue should follow all other evidence collecting procedures.

        2. Tissue Fixative

• 10% Formalin is a common fixative used.

    A. Dental Records

• Whenever possible the dental records of the individual should be obtained in accordance with the ABFO Bitemark Analysis Guidelines.

    B. Photographic Documentation of the Dentition

• Photographs of the dentition should be taken by the forensic dentist or by the odontologist's direction.

• A scale such as the ABFO No. 2 scale should be utilized when using a scale in these photographs.

• Video or digital imaging can be used to document the dentition when utilized in addition to conventional photography.

• Tripods and/or focusing rails can be used at the discretion of the photographer.

• Extraoral Photographs

• A frontal full face view and a view with the teeth in centric should be taken.

• Intraoral Photographs

• Maxillary and Mandibular occlusal views of the dentition should be taken whenever possible.

• Lateral views of the dentition may be taken.

    C. Clinical Examination

        1. Extraoral Considerations

• Maximum vertical opening and any deviations should be noted whenever possible.

• Evidence of surgery, trauma and/or facial asymmetry should be noted.

• TMJ function may be checked in addition to the previous observations.

• Muscle tone and balance may also be checked in addition to the previous observations.

        2. Intraoral Considerations

• Missing and misaligned of teeth should be noted.

• Broken and restored teeth should be noted.

• The periodontal condition and tooth mobility should be noted whenever possible.

• Previous dental charts should be reviewed if available.

• Occlusal disharmonies should be noted whenever possible.

• The tongue size and function may be noted in addition to the previous observations.

• The bite classification may be noted in addition to the previous observations.

    D. Dental Impressions

• Dental impressions, following the ABFO Bitemark Analysis Guidelines, should be taken by the forensic dentist or by the odontologist's direction.

• Bite exemplars should be obtained in addition to the dental impressions.

    E. Saliva Samples

• Saliva swabbings should be obtained if appropriate.

A 1994 survey of Diplomates of the American Board of Forensic Odontology indicated that they presently use the following analytic methods in the comparison of Bitemark evidence.

1. Generation of Overlays

    A. Acetate tracing directly from models of the suspect.

    B. Acetate tracing indirect from photocopy of model with scale.

    C. X-ray film overlay created from radiopaque material applied to the wax bite.

    D. Alternative methods

• Life-sized photos of model printed on acetate film.

• Greater than life-sized photos of models on acetate.

    A. Wax exemplars (aluwax, baseplate wax, etc.)

    B. Styrofoam

    C. Volunteer's skin

    D. Alternative Methods

• Fruits

• Clay

    A. Acetate Tracings to life-size photos of wound

    B. Working study model of teeth to life-size photo of wound

    C. Working study model to impression of wound or to actual victim

    D. Acetate overlays of teeth compared to greater than life-size photo of wound:

• Five times life-size

• Three times life-size

• Two times life-size

• Transillumination of tissue

• Computer enhancement and/or digitization of mark and/or teeth

• Stereomicroscopy and/or macroscopy

• Scanning Electron Microscopy

• Videotape

• Caliper utilization for measurement

1. All Diplomates of the American Board of Forensic Odontology are responsible for being familiar with the most common analytical methods reported in this study.

2. All Diplomates of the American Board of Forensic Odontology should utilize appropriate analytical methods in their analysis of the evidence.

3. A list of all the evidence analyzed and the specific analytical procedures should be included in the body of the final report. All available evidence associated with the Bitemark must be reviewed prior to rendering an expert opinion.

4. Any new analytical methods not listed in the previously described list of analytical methods should be thoroughly explained in the body of the report. New analytical methods should be scientifically sound and duplicated by other forensic experts. New analytical methods should, if possible, be "backed up" with the use of one or more of the accepted techniques listed in these guidelines.

History

These guidelines are the result of a collective effort of the participants of the bitemark workshop of the American Board of Forensic Odontology assembled in Anaheim, California, February 18th through 20th, 1984. These guidelines are considered dynamic, not static, and will be modified as significant developments evolve. Careful use of these guidelines in any bitemark analysis will enhance the quality of the investigation and conclusion.

Description of Bitemark

Both in the case of a living victim or deceased individual, the odontologist should determine and record certain vital information.

    1. Demographics

• Name of victim

• Case Number

• Date of examination

• Referring agency

• Person to contact

• Age of victim

• Race of victim

• Sex of victim

• Name of examiner(s)

    2. Location of Bitemark

• Describe anatomical location

• Describe surface contour: flat, curved or irregular

• Describe tissue characteristics

            A. Underlying structure: bone, cartilage, muscle, fat

            B. Skin: relatively fixed or mobile

    3. Shape

• The shape of the bitemark should be described; e.g. essentially round, ovoid, crescent, irregular, etc.

    4. Color

• The color should be noted; e.g. red, purple, etc.

    5. Size

• Vertical and horizontal dimensions of the bitemark should be noted, preferably in the metric system.

    6. Type of Injury

• Petechial hemorrhage

• Contusion (ecchymosis)

• Abrasion

• Laceration

• Incision

• Avulsion

• Artifact

    7. Other Information

• It should be also be noted whether the skin surface is indented or smooth.

• At some point, the odontologist will evaluate the evidence to determine such things as position of maxillary and mandibular arches, location and position of individual teeth, intradental characteristics, etc. This may or many not be possible at the time of initial examination and will be covered below.

Collection of Evidence From Victim

It is assumed that evidence gathering from bitemark victims will be done with authorization from the appropriate authorities.

It should first be determined whether the bitemark has been affected by washing, contamination, lividity, embalming, decomposition, change of position, etc.

1. Photography

A variety of types of photographic equipment and films may be used as described below.

• Orientation and closeup photographs should be taken.

• Photographic resolution should be of high quality.

• If color film is used, accuracy of color balance should be assured.

• Photographs of the mark should be taken with and without a scale in place.

• When the scale is used, it should be on the same plane and adjacent to the bitemark. It presently appears desirable to include a circular reference in addition to a linear scale.

• The most critical photographs should be taken in a manner that will eliminate distortion.

• In the case of a living victim, it may be beneficial to obtain serial photographs of the bitemark.

2. Salivary Swabbing

• Whenever possible, salivary trace evidence should be collected according to recommenda- tions of the testing laboratory.

3. Impressions

• Impressions should be taken of the surface of the bitemark whenever it appears that this may provide useful information.

• The impression materials used should meet American Dental Association specifications and should be identified by name in the report.

• Suitable support should be provided for the impression material to accurately reproduce body contour.

• The material used to produce the case should accurately represent the area of impression and should be prepared according to the manufacturer’s instructions.

4. Tissue Samples

• Tissue specimens of the bitemark should be retained whenever it appears this may provide useful information.

Before collecting evidence from the suspect, the odontologist should ascertain that the necessary search warrant, court order or legal consent has been obtained, and should make a copy of this document part of his records. The court document or consent should be adequate to permit collection of the evidence listed below:

1. History

Obtain history of any dental treatment subsequent to, or in proximity to, the date of bitemark.

2. Photography

Whenever possible, good quality extraoral photographs should be taken, both full face and profile. Intraoral photographs preferably would include frontal view, two lateral views, occlusal view of each arch, and any additional photographs that may provide useful information. It is also useful to photograph the maximum interincisal opening with scale in place. If inanimate materials, such as foodstuffs, are used for test bites the results should be preserved photographically.

3. Extraoral Examination

The extraoral examination should include observation and recording of significant soft and hard tissue factors that may influence biting dynamics, such as temporomandibular joint status, facial asymmetry, muscle tone and balance. Measurement of maximal opening of the mouth should be taken, noting any deviations in opening or closing, as well as any significant occlusal disharmonies. The presence of facial scars or evidence of surgery should be noted, as well as the presence of facial hair.

4. Intraoral Examination

• In cases in which saliva evidence has been taken from the victim, saliva evidence should also be taken from the suspect in accordance with the specifications of the testing laboratory.

• The tongue should be examined in reference to size and function. Any abnormality such as ankyloglossia should be noted.

• The periodontal condition should be observed with particular reference to mobility and areas of inflammation or hypertrophy. Also, if anterior teeth are missing or badly broken down it should be determined how long these conditions have existed.

• It is recommended that, when feasible, a dental chart of the suspect’s teeth be prepared, in order to encourage thorough study of the dentition.

5. Impressions

Whenever feasible, at least two impressions should be taken of each arch, using materials that meet appropriate American Dental Association specifications and are prepared according to the manufacturer’s recommendations, using accepted dental impression techniques. The interocclusal relationship should be recorded.

6. Sample Bites

Whenever feasible, sample bites should be made into an appropriate material, simulating the type of bite under study.

7. Study Casts

• Master casts should be prepared using American Dental Association approved Type II stone prepared according to manufacturer’s specifications, using accepted dental techniques.

• Additional casts may be fabricated in appropriate materials for special studies. When additional models are required, they should be duplicated from master casts using accepted duplication procedures. Labeling should make it clear which master cast was utilized to produce a duplicate.

• The teeth and adjacent soft tissue areas of the master casts should not be altered by carving, trimming, marking or other alterations.

In 1993, the ABFO Bitemark Workshop #2 Committee distributed a questionnaire on Bitemark terminology. About half of our members responded and provided the basis of the Bitemark Terminology survey reviewed at the three day Bitemark Workshop in San Antonio on February 12-14, 1994. Suggestions for modifications were made at that time and these were incorporated into the finished work-product which was accepted by the Diplomates of the ABFO on February 13, 1995, in Seattle, Washington.

Rationale

Please read Bitemark Terminology with the following perspective:

There is a need for forensic dentists to agree on language and terminology used in bitemark cases so as to avoid miscommunicating facts and opinions to attorneys, judges, juries and other dentists. It is not expected that this document is perfectly ideal to all forensic dentists. However, it represents majority opinions and has the highest level of acceptance to the largest number of odontologists. Please consider that major substantive changes at this time would probably make the document less representative of the group’s wishes. All Diplomates (and other forensic odontologists) will have to make some compromises if the science of forensic odontology is to achieve the higher objective of universally agreeable communication.

There is no intention for the ABFO to mandate language as it is used within the body of a report or in testimony when responding to specific or hypothetical questions. There is no intention to preclude the use of terms so long as they ethically and accurately communicate an odontologist’s analysis and opinion.

There is every intention for the ABFO, as a credible body of experts, to present a clear and unified message as to what its members mean when they state a conclusion. This document will present language that has been agreed upon and approved for communicating bitemark opinions.

In keeping with the commitment not to stifle language, this document will not formally define terms but will merely give their connotation, indicate parameters of meaning and present acceptable synonyms and alternatives.

Bite mark vs. Bitemark

The noun bite mark (two words) is used more frequently in the literature than bitemark (one word) and was preferred 3:1 in the ABFO survey. Dr. S. Miles Standish presented a cogent rationale for the single term, bitemark, as the preferred grammatical form. A professor of English at the University of Louisville concluded that, because language is a living thing, either term is acceptable. Bitemark implies a type of mark whereas bitemark connotes an entity unto itself and recognizable as such. Bitemark would be considered the more progressive term, signifying that odontologists have a sufficient body of work and evolved in similar fashion. Dr. Standish also adds that, when used as a compound adjective, bite mark is hyphenated as in Bitemark analysis. After evaluating all these opinions, it is the feeling of the ABFO that the meaning of the word in any of its forms is clear and there is no need for the ABFO to endorse a particular form.

Component Injuries Seen in Bitemarks

Abrasions (scrapes), contusions (bruises), lacerations (tears), ecchymosis, petechiae, avulsion, indentations (depressions), erythema (redness) and punctures might be seen in bitemarks. Their meaning and strict definitions are found in medical dictionaries and forensic medical texts and should not be altered. An incision is a cut made by a sharp instrument and, although mentioned in the Bitemark literature, it is not an appropriate term to describe the lacerations made by incisors.

The term latent injury or wound was preferred over occult or trace wound when referring to an injury which is not visible but can be brought out by special techniques.

A Characteristic (as it pertains to bitemarks)

A characteristic, as applied to a bitemark, is a distinguishing feature, trait or pattern within the mark. Characteristics are two types, class characteristics and individual characteristics.

Class characteristic: a feature, trait or pattern preferentially seen in, or reflective of, a given group. For example, the finding of linear or rectangular contusions at the midline of a Bitemark arch is a class characteristic of human incisor teeth. "Incisors" represent the class in this case. The value of identifying class characteristics is that, when seen, they enable us to identify the group from which they originate. For instance, the class characteristics of incisors (rectangles) differentiates them from canines (circles or triangles). If we define the class characteristics of human bites, we can differentiate them from animal bites. Via class characteristics, we differentiate the adult from the child bite or mandibular from maxillary arch. The original term "class characteristic" was applied to toolmarks and its definition has been modified to make it more applicable to bitemarks.

Individual characteristic: a feature, trait or pattern that represents an individual variation rather than an expected finding within a defined group. An example of this is a rotated tooth. The value of individual characteristics is that they differentiate between individuals and help identify the perpetrator. The number, specificity and accurate reproduction of these individual characteristics determine the confidence level that a particular suspect made the bitemark.

Bitemark:

• A physical alteration in a medium caused by the contact of teeth.

• A representative pattern left in an object or tissue by the dental structures of an animal or human.

Cutaneous Human Bitemark:

• An injury in skin caused by contacting teeth (with or without the lips or tongue) which shows the representational pattern of the oral structures.

[COMMENT: These represent succinct, workable definitions. They lack 100% precision because they exclude the rare cases of denture markings and tooth contact marks without biting action. However, a definition that encompasses all possible tooth/mouth-to-medium contacts would be too cumbersome for practical application.]

A circular or oval (doughnut) (ring-shaped) patterned injury consisting of two opposing (facing) symmetrical, U-shaped arches separated at their bases by open spaces. Following the periphery of the arches are a series of individual abrasions, contusions and/or lacerations reflecting the size, shape, arrangement and distribution of the class characteristics of the contacting surfaces of the human dentition.

Variations of the Prototypical Bitemark

Variations include additions, subtractions and distortions.

    1. Additional features:

• Central Ecchymosis (central contusion) - when found, these are caused by two possible phenomena:

            A) positive pressure from the closing of teeth with disruption of small vessels.

            B) negative pressure caused by suction and tongue thrusting.

• Linear Abrasions, Contusions or Striations - these represent marks made by either slipping of teeth against skin or by imprinting of the lingual surfaces of teeth. The term drag marks is in common usage to describe the movement between the teeth and the skin while lingual markings is an appropriate term when the anatomy of the lingual surfaces are identified. Other acceptable descriptive terms include radial or sunburst pattern.

• Double Bite - a "bite within a bite" occurring when skin slips after an initial contact of the teeth and then the teeth contact again a second time.

• Weave Patterns of interposed clothing.

• Peripheral Ecchymosis - due to excessive, confluent bruising.

    2. Partial Bitemarks:

• one-arched (half bites).

• one or few teeth.

• unilateral (one-sided) marks - due to incomplete dentition, uneven pressure or skewed bite.

    3. Indistinct/Faded Bitemarks:

• Fused Arches - collective pressure of teeth leaves arched rings without showing individual tooth marks.

• Solid - ring pattern is not apparent because erythema or contusion fills the entire center leaving a filled, discolored, circular mark.

• Closed Arches - the maxillary and mandibular arch are not separate but joined at their edges.

• Latent - seen only with special imaging techniques.

    4. Superimposed or Multiple Bites.

    5. Avulsive Bites.

[COMMENT: This list excludes variations caused by individual characteristics of the biter’s teeth.]

Unique:  This term is variably defined as either one of a kind or rare and unusual. In its most conservative interpretation the following connotations apply:

• of such distinctiveness that no other person could have made an identical pattern.

• to the point of persuasion of individuality.

• attributable to only one individual.

• unequaled .

To those who use a more liberal interpretation the following would apply:

• unusual.

• rare.

[COMMENT: Forensic odontologists should specify their meaning when they use the word unique.]

Distinctive:

• variation from normal, unusual, infrequent.

• not one of a kind but serves to differentiate from most others.

• highly specific, individualized.

• lesser degree of specificity than unique.

[COMMENT: A consensus of odontologists indicated that in the hierarchy of the terminology, "unique" implies greater rarity than "distinctive".]

Terms Indicating Degree of Confidence That an Injury is a Bitemark

Possible Bitemark:  An injury showing a pattern that may or may not be caused by teeth; could e caused by other factors but biting cannot be ruled out.

• criteria: general shape and size are present but distinctive features such as tooth marks are missing, incomplete or distorted or a few marks resembling tooth marks are present but the arch configuration is missing.

Probable Bitemark:  The pattern strongly suggests or supports origin from teeth but could conceivably be caused by something else.

• criteria: pattern shows (some) (basic) (general) characteristics of teeth arranged around arches.

Definite Bitemark:  There is no reasonable doubt that teeth created the pattern; other possibilities were considered and excluded.

• criteria: pattern conclusively illustrates (classic features) (all the characteristics) (typical class characteristics) of dental arches and human teeth in proper arrangement so that it is recognizable as an impression of the human dentition.

[COMMENT: These terms are opinions, representing 3 zones of confidence and do not convey a statistical or mathematical measurement of precision. A lesser quality bitemark can be elevated to definite if multiple bitemarks are present or if amylase is positive.]

Ordinate Ranking                                            Connotation

of Terms

COMMENT: The above ranked terms are to define the injury itself as opposed to the terms used to describe the degree of certainty that a particular set of teeth caused the wound. Please refer to the "Terms to indicate the Link Between Bitemark and the Suspect(s)" for acceptable terms used to describe the comparison opinion.

Point, Concordant Point, Area of Comparison, Match, Consistent

    Point:

• a singular unit or feature available for comparison or evaluation

• an area attributable to a tooth

• a way of counting features

[COMMENT: This term is used as a convenience in reports to address specific components of the bitemark which are being compared to teeth. A point doesn’t imply any degree of specificity and not a characteristic.]

    Concordant Point:

• point seen in both the bitemark and the suspect(s') exemplars.

• corresponding feature.

• comparable element.

• unit of similarity.

• matching point.

    Area of Comparison:

• a dynamic or specific region to be compared.

• a complex or pattern made up of a conglomerate of several points or a group of features.

    Match:

• nonspecific term indicating some degree of concordance between a single feature, combi nation of features or a whole case.

• an expression of similarity without stating degree of probability or specificity.

[COMMENT: This term "match" or "positive match" should not be used as a definitive expression of an opinion in a Bitemark case. The statement "It is a positive match" or "It is my opinion that the bitemark matches the suspect’s teeth" will likely be interpreted by juries as tantamount to specific perpetrator identification when all the odontologist might mean is that a poorly-defined or nonspecific bitemark was generally similar to the suspect’s teeth, as it might to a large percentage of the population.]

    Consistent (compatible) With:

• synonymous to" match", a similarity is present but specificity is unstated.

[COMMENT: If used to represent the odontologist’s conclusion, the term "consistent with" should be explained in the report or testimony as indicating similarity but implying no degree of specificity to the match. This is necessitated by the fact that our survey showed that this term varied in meaning among odontologists to indicate everything from " possible" to "absolute certainty"; its message is unreliable. However, when used as proposed, it is an acceptable term for those odontologists who are reluctant to suggest culpability of a suspect.]

Possible Biter:

• could have done it; may or may not have.

• teeth like the suspect’s could be expected to create a mark like the one examined but so could other dentitions.

Criteria: there is a nonspecific similarity or a similarity of class characteristics; match points are general and/or few, and there are no incompatible inconsistencies that would serve to exclude.

[COMMENT: This term is approximately synonymous with "consistent with" but has a more universally understandable meaning.]

Probable Biter:

• suspect most likely made the bite; most people in the population could not leave such a mark.

Criteria: bitemark shows some degree of specificity to the individual suspect’s teeth by virtue of a sufficient number of concordant points including some corresponding individual characteristics. There is an absence of any unexplainable discrepancies.

Reasonable Medical Certainty:

• highest order of certainty that suspect made the bite.

• the investigator is confident that the suspect made the mark.

• perpetrator is identified for all practical and reasonable purposes by the bitemark.

• any expert with similar training and experience, evaluating the same evidence should come to the same conclusion of certainty.

• any other opinion would be unreasonable.

Criteria: there is a concordance of sufficient distinctive, individual characteristics to confer (virtual) uniqueness within the population under consideration. There is absence of any unexplainable discrepancies.

[COMMENT: The term reasonable medical certainty conveys the connotation of virtual certainty or beyond reasonable doubt. The term deliberately avoids the message of unconditional certainty only in deference to the scientific maxim that one can never be absolutely positive unless everyone in the world was examined or the expert was an eye witness. The Board considers that a statement of absolute certainty such as "indeed, without a doubt", is unprovable and reckless. Reasonable medical certainty represents the highest order of confidence in a comparison. It is, however, acceptable to state that there is "no doubt in my mind" or "in my opinion, the suspect is the biter" when such statements are prompted in testimony.]

        Terms                                                                 Connotation

[COMMENT: Using numbers and percentages to represent opinions is inappropriate unless a specific statistical analysis on a case has been done.]

The following list of Bitemark Terminology Standards have been accepted by the American Board of Forensic Odontology.

1. Terms assuring unconditional identification of a perpetrator, without doubt, on the basis of an epidermal bitemark and an open population is not sanctioned as a final conclusion.

2. Terms used in a different manner from the recommended guidelines should be explained in the body of a report or in testimony.

3. Certain terms have been used in a nonuniform manner by odontologists. To prevent miscommunication, the following terms, if used as a conclusion in a report or in testimony, should be explained:

• match; positive match.

• consistent with.

• compatible with.

• unique.

4. The following terms should not be used to describe bitemarks:

• suck mark (20% of diplomates still use this antiquated term).

• incised wound.

5. All boarded forensic odontologists are responsible for being familiar with the standards set forth in this document.

General Comments

The following outline lists recommended components of a forensic report regarding a bitemark analysis. This is a continuation of previous guidelines established by the ABFO and follows a natural progression of events as we have existing terminology guidelines and standards already established. It is the hope that these report-writing guidelines will establish a uniform way of using the terminology guidelines/standards to present expert opinions in a logical, complete and defendable manner.

This report protocol is fairly standard for forensic reports. The introduction is fairly standard and would include when and who was the initial contact and what we were requested to do.

The next section is an inventory of the evidence that is available for analysis. There are two Section II’s and the odontologist would use the one that is appropriate. The only difference between the two is that if the odontologist collects the evidence then a description of the evidence collection procedures should be included in the report. If the odontologist does not collect the material then a simple inventory would suffice. It is the responsibility of the person that collected the information to demonstrate that the evidence was collected properly and met the current ABFO guidelines and standards. If items listed here are not available or were not obtained, the reason for their omission should be noted.

The remaining sections are self-explanatory. The ABFO Bitemark Terminology Guidelines and Standards should be followed in all written communications regarding the evidence, analysis and opinions. This will eliminate a lot of confusion and misunderstanding concerning the expert’s opinions.

The order in which the information is presented is important in laying a sound foundation for the stated opinion. The analysis of the injury should include the expert’s opinion concerning the degree of certainty that it is a bitemark. Following this is a description of the dentition that will be used for the comparison. Details of the comparison procedures should follow the description of the dentition. Finally, the expert’s opinion as to the degree of certainty that there is a link (or non-link) between the dentition and the bitemark should be stated clearly and follow the recommended terminology as noted in the ABFO Bitemark Terminology Guidelines.

With the proliferation of desktop publishing type of word processors it is extremely effective to include appropriate annotated images in the body of the text. This is a very effective way of expressing opinions. As with the other guidelines that have been established by the ABFO, these guidelines are not static and will be changed as new techniques and advances are made in the field of Forensic Odontology.

The Diplomates of the American Board of Forensic Odontology, Inc. approved these Guidelines, on February 15, 1999.

Suggested Components of a Forensic Odontology Report Re: Bitemarks

I. Introduction

    a. When and Who contacted you requesting services.

II. Inventory of Evidence Received (if not involved directly with the evidence collection).

    a. Injury Evidence

        1. # and type of photographs

        2. # and type of impressions

        3. # and type of casts

        4. Description of tissue Samples and how they were preserved and packaged

    b. Dentition Evidence

        1. Description of intra- and extra-oral examination

        2. # and type of photographs

        3. # and type of wax bites/impressions

        4. # and type of impressions

        5. # and type of casts

OR

II. Evidence Collection Procedures (if involved directly with the evidence collection)

a. Description of evidence collection procedures in chronological order. (both for injury and dentition)

b. Itemized list of the types and quantity of evidence collected. (the same as listed above.)

III. Analysis of Injury Evidence

a. Description of the injury using ABFO Bitemark Terminology Guidelines.

b. Appropriate embedded annotated images.

c. Description of the quality of the evidence. (photographic distortion? etc.)(If Appropriate)

d. Description of analytical procedures used to analyze the injury. (trans., microscopy, etc.)

e. Opinions as to the degree of certainty that the injury is a bitemark (using guidelines and standards) and justification for this degree of certainty.

IV. Analysis of Dentition

a. Description of the dentition(s) being compared to the injury.

b. Appropriate embedded annotated images.

c. Description of the evidence taken of the dentition. (If Appropriate)

d. Description of procedures used to prepare evidence for comparison to the bitemark. (exemplars, etc.)

e. Define Dental Numbering System used in the report. (If Appropriate)

V. Comparison Procedures

a. Description of the procedures utilized to compare the dentition to the bitemark using the   ABFO Bitemark Methodology Guidelines and Standards.

VI. Opinions

a. Description of the degree of certainty for link between the dentition and the bitemark using the ABFO Bitemark Terminology Guidelines and Standards with justification for this degree of certainty.

b. Appropriate embedded annotated images.