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Collection and Preservation of Postmortem Dental Evidence

    1. The Remains - Examination Procedures

    2. Photography

    3. Jaw Resection

    4. Techniques for Dissection/Resection

    5. The Postmortem Dental Record

Sources for Antemortem Data

 

Comparison of Antemortem and Postmortem Evidence

 

Categories and Terminology for Body Identification

 

 

 

ABFO Body Identification Guidelines

 

History

 

The necessity for guidelines and standards in the forensic sciences should be obvious. The American Board of Forensic Odontology (ABFO) adopted Guidelines for Bite Mark Analysis on February 21, 1984. The committee on Body Identification Guidelines have prepared a similar document for body identification.

Forensic dentistry has provided accurate identifications in mass disasters and in routine cases over the past years, but there have been cases where misidentifications have occurred. The objective of these guidelines is to provide guidance to the forensic dentist and are dedicated to the concept of greater accuracy in forensic dentistry.

The Body Identification Guidelines have received general acceptance by diplomates of the ABFO, following a preliminary draft by the committee. It is understood, however, that some diplomates may follow alternative techniques that may be equally effective. It is not the purpose of these guidelines to invalidate other methods, but rather to describe methods that a majority of investigators employ.

 

Collection and Preservation of Postmortem Dental Evidence

 

The postmortem dental examination is conducted by the authority and under the direction of the coroner/medical examiner or his designee, typically a forensic pathologist. Thus, the protocol for the collection of postmortem dental evidence, particularly decisions to incise the facial tissues for access or resect the jaws, is subject to approval by the regional coroner/medical examiner. The actual procedures to be followed in a dental identification case depend in large part on the condition of the remains (as well as other circumstances of the case).

 

1. Examination Procedures

 

    Visually Identifiable Body

        Photographs.

        Radiographs.

        Dental Charting.

        Dental Impressions, as applicable.

        Resection by Infra-mandibular Dissection.

    Decomposed/Incinerated Body

        Photographs.

        Radiographs.

        Dental Charting.

        Resection and Preservation of Jaw Specimens, if indicated.

    Skeletonized Remains

        Photographs.

        Radiographs.

        Dental Charting.

        Preservation of Jaw Specimens, if indicated.

 

2. Photography

 

Photographic documentation of dental evidence can provide objective data which is often more graphic than the written chart. Photographs (with an accompanying scale) should be taken before and after appropriate cleansing. The ABFO right angle ruler is recommended. The photographs should be clearly labeled with the case number/name and date. All relevant photographic information should be documented.

 

Recommended Equipment

Single lens reflex 35 mm. camera (The Lester Dine instant closeup camera, model IV, has been useful in mass disaster evidence documentation). Bellow system and/or lenses for closeup photography. Electronic flash (preferably point flash or ring light system).

Cheek retractors.

Intraoral front-surface mirrors.

Film

Color film (slide and/or print format).

Black and white film, as required.

Polaroid film may be of help in special circumstances.

Views

Full face, lips retracted.

Closeup view of anterior teeth.

Lateral views of teeth in slightly open position, and in occlusion.

Occlusal views, upper and lower teeth.

Special views, as required.

 

3. Jaw Resection

 

Facial dissection and/or jaw resection, which may be necessary for full access to dental structures, is done only with approval of the coroner/medical examiner. Ordinarily, the circumstances dictating decisions to resect are applicable as follows:

 

Viewable Bodies; Restricted opening due to rigor may require:

Intraoral incision of masticatory muscles, with or without fracture of the condyles.

Breaking the rigor with bilateral leverage on the jaws in the retro molar regions.

Waiting until the rigor subsides.

Infra-mandibular dissection with or without mandibular resection.

 

Removal of the larynx and tongue at autopsy may facilitate the visual examination of the teeth and placement of intraoral films. Again, the removal of these tissues should only be performed after the autopsy and with permission of the pathologist. These tissues should either be retained by the pathologist or replaced with the body.

 

Decomposed, Incinerated, or Fragmented Bodies :

Jaw resection in such cases facilitates dental charting and radiographic examination. Careful dissection of the incinerated head, in particular, is required to preserve fragile tooth structure and jaws in situ. Radiographs should be made prior to manipulation of badly burned fragments (mechanical or chemical), stabilization of such tissue should be instituted where necessary.

 

Skeletonized Remains: 

Once the skull and mandible are readily separated from the remainder of the skeleton, resection of the maxilla is not required.

 

Preservation of Evidence: 

Jaw resection may be indicated in cases in which:

Body parts are to be transferred, with proper authorization, to other facilities for additional examination and testing.

A homicide victim is to be cremated.

 

4. Techniques for Dissection/Resection

 

Selected techniques are described below. Other methods may be employed when indicated.

 

Facial Dissection:

Bilateral incisions of the face. Beginning at the oral commissures and extending posteriorly to the anterior ramus, permit reflection of the soft tissues for better access.

 

Infra-mandibular Approach:

Bilateral incisions are made across the upper anterior neck and extend to points poster- ior and inferior to the ears. The skin and underlying tissues are then reflected upward over the lower face thereby exposing the mandible.

 

Jaw Resection

Stryker Autopsy Saw Method:

The soft tissue and muscle attachments on the lateral aspect of the mandible are dissected away by incisions which extend through the muco-buccal fold to the lower border of the mandible. Lingual attachments are similarly incised to include the internal pterygoid attachments to medial aspect of the rami and the masseter attachments on the lateral aspect. On the maxilla, facial attachments are incised high on the malar processes and superior to the anterior nasal spine. Stryker saw cuts are made high on the rami to avoid possible impacted third molars. Alternatively, the mandible may also be removed by disarticulation at the temporomandibular joints. Bony cuts on the maxilla are made high on the malar processes and above the anterior nasal spine to avoid the apices of the maxillary teeth. A surgical mallet and chisel inserted in the Stryker saw cuts in the malar processes and above the anterior nasal spine are used to complete the separation of the maxilla.  Remaining soft tissues in the soft palate and fauces are then dissected free.

 

Mallet and Chisel Method:

A mallet and chisel can be used to induce a "Le Fort" Type I fracture of the maxilla. The chisel blows are made below the zygomatic arch, high on the maxillary sinus walls bilaterally. Since it is virtually impossible to fracture the mandibular rami with the mallet and chisel, the mandible can be disarticulated at the temporomandibular joint in such cases.

 

Pruning Shears Method:

An alternative technique for resection of the jaws involves the use of large pruning shears. The small blade of the pruning shears is placed within the nares and forced back into the maxillary sinus. A cut is then made along a plane superior to the apices of the maxillary teeth bilaterally. The mandibular bone cuts are performed by inserting the small blade of the shears high on the lingual aspect of the ramus near the coronoid notch bilaterally.

 

5. The Postmortem Dental Record

 

While most morgues will have the standard autopsy equipment, the forensic odontologist may wish to assemble his own forensic kit to include mouth mirrors, explorers, camera equipment, anatomic dental charts, impression materials, etc. Postmortem dental examinations might utilize anatomic dental charts, photographs, radiographs, models, tape recordings and/or narrative descriptions. The data collected should be comprehensive in scope since antemortem records are commonly not discovered until days, weeks or even years later. Accordingly, the postmortem dental record will include all or most of the items listed.

 

Basic Data

    Case Number

    Date/Time

    Jurisdiction/Authority

    Location

    Tentative ID, if any

 

Body Description, General

    Approximate Age

    Race

    Sex

    Condition

 

Jaw Fragment(s)

    Description

 

6. Dental Examination

 

The universal tooth numbering system should be used. The record should reflect any missing dental structures or jaw fragments as well as those present and available for evaluation. The chart should illustrate as graphically as possible the following:

 

Configuration of all dental restorations (including prostheses), caries, fractures, anoma lies, abrasions, implants, erosions or other features for all teeth.

Materials used in dental restorations and prosthetic devices, when known.

Periodontal conditions, calculus, stain.

Occlusal relationships, malposed teeth; anomalous, congenitally missing and supernumer- ary teeth.

Intraoral photographs should be used to show anatomic details of teeth restorations, periodontium, occlusion, lesions, etc.

 

7. Narrative Description and Nomenclature

 

The anatomic dental chart may be supplemented by a narrative description of the postmortem findings with particular emphasis on unusual or unique conditions. Standardized dental nomen- clature should be used as follows:

 

Universal Numbering System:

The system of numbering teeth used in the United States. The teeth are numbered from 1 to 32. The upper right third molar is #1, the upper central incisors are #8 and #9, the upper left third molar #16, the lower left third molar #17 and the lower right third molar is #32. The universal tooth numbering system plus the actual name of the tooth should be used(e.g. tooth #3, upper right first permanent molar).

 

Dentition Type and Tooth Surfaces

Primary, Permanent and Mixed Dentition.

Mesial, Occlusal, Distal, Facial and Lingual Surfaces.

Prosthetics and other Appliances

Crowns: full, 3/4 or 7/8 coverage restorations. Prostheses: Partial, full, or fixed. 

Orthodontic bands, brackets, space maintainers and retainers.

Mouth guards and night guards.

 

The FDI Numbering System

Odontologists should be aware of the FDI system of numbering teeth. This system is used through out the developed world. Quadrants are numbered from 1 to 4. The upper right quadrant is 1, upper left 2, lower left 3 and lower right 4. Teeth are numbered from the midline to the posterior. Central incisors are #1, canines #3 and third molars #8. Teeth are represented by a two digit code with the quadrant first and the tooth second. Thus, the upper left first molar is #26.

 

 

8. Dental Impressions

 

Impressions should be considered when bitemarks, rugae patterns or other evidence warrant the procedure.

 

Supplies and Equipment

Appropriate trays, plastic or metal, which can be modified to fit the mouth.

Alginate or other American Dental Association approved dental impression material.

Dental stone is the material of choice for pouring models. Plaster of Paris should not be used.

 

Impressions and Preparation of Models

Two sets of impressions, both maxillary and mandibular, are obtained in the conventional manner.

Models should be trimmed and appropriately labeled with the case number and date.

 

 

 

9. Dental Radiology

 

Postmortem radiographs graphically complement the visual examination/charting of the oral and perioral structures and can provide significant data essential for identification (see section III). In general, radiographs are required in cases where there is no putative ID, antemortem records have not yet been located and/or the jaws can not be retained. Postmortem radiographs must be considered the prime method of identification. A comprehensive postmortem radiographic examination might include all or some of the following views, depending on the circumstances of the case:

 

Intraoral Radiographs

Bitewing and periapical radiographs of anterior and posterior teeth comparable to those taken antemortem. ("Bitewing" views need not be taken in the conventional manner with the teeth in occlusion; rather, periapical film can be used for separate views of the upper and lower teeth, using a horizontal bitewing angulation.)

 

Dental Fragments, Dissociated Teeth

Appropriate radiographs of all dental fragments, dissociated teeth, bone and restorations should be obtained. Occlusal or lateral plate film may be used for objects larger than a periapical film.

 

Edentulous Areas

Periapical radiographs of edentulous arches or areas, especially the third molars, which may be impacted or previously extracted.

Periapical radiographs of sockets of teeth lost postmortem should be taken, since antemortem radiographs of these same teeth may be the only evidence that becomes available.

 

Extraoral Radiographs

Extraoral radiographs (e.g., lateral jaw, maxillary or frontal sinus and panoramic radiographs) are often useful.

 

Disposition of Radiographs

Double pack intraoral film is recommended.

One set of films should be retained by the forensic odontologist for his case  file. The second set may be mounted and forwarded with a written report to the medical examiner/ coroner for the master file.

 

NOTE: All duplicate films should bear right and left notations.

 

 

 

Sources for Antemortem Data

 

Antemortem data may include as dental radiographs, written records, models and photographs. Original radiographs should be obtained if possible. The discovery and collection of antemortem records is ordinarily the responsibility of the investigative agency who has access to missing persons reports at the local, state or national level. However, the forensic odontologist may recognize additional characteristics (e.g., prior orthodontic treatment) which could be helpful in establishing a potential ID. This section lists a variety of resource agencies and/or individuals that might provide assistance in locating records.

 

1. Local Agencies:

Hospitals, Other Health Care Facilities.

Dental Schools.

Health Care Providers.

Employer Dental Insurance Carrier.

Public Aid Insurance Administrator.

 

2. State Agencies:

Contact state or local agencies for dental record assistance.

 

3. Federal Agencies:

 

FBI National Crime Information Center (NCIC)

 

Council on Dental Affairs and the Federal Dental Service

1111 14th Avenue, NW, #1200

Washington, DC 20005

 

Military Records Depository

900 Page Blvd.

St. Louis, MO

 

4. Insurance Carriers

 

 

5. Other Sources

Family/Friends/Coworkers.

Public aid insurance administrator.

Employer dental insurance carrier.

Prior military service.

Prior judicial detention in county.

State or Federal institutions.

Prior hospitalizations (e.g. chest films, skull films).

Oral surgeons in the area.

Veterans administration hospitals.

Any previous areas of residence.

Chiropractic x-rays.

If evidence of ortho treatment, orthodontists in the area.

 

 

Comparison Of Antemortem & Postmortem Evidence

 

This section deals with factors which may be present in both the antemortem and postmortem dental evidence and can be useful for comparison purposes. Most dental identifications are based on restorations, caries, missing teeth and/or prosthetic devices which may be readily documented in the records. It should be noted, however, that the precipitous decrease in caries incidence in recent years will dictate greater reliance on other dental findings in the future. It is emphasized that, given adequate records, a nearly infinite number of objective factors have identification value (see Section IV). Thus, objective findings, particularly those which are unique to the individual, provide the basis for concordance or exclusion.

Concomitantly, apparent discrepancies between the antemortem and postmortem evidence (e.g. errors in recording, dental treatment subsequent to the available antemortem record) must be resolved.

The following subsections provide examples of objective findings in the teeth, periodontium, and/or jaws, which may be demonstrable in both antemortem and postmortem records. While the factors listed are by no means comprehensive, they may serve as a checklist and demonstrate the range of objective findings that may be applicable in difficult identification cases.

 

Dental Features Useful in Identification

 

Teeth

Teeth present.

Erupted.

Unerupted/impacted.

Missing teeth.

    Congenitally missing. 

    Lost antemortem. 

    Lost perimortem/postmortem.

Tooth Type

    Permanent.

    Mixed dentition.

    Retained primary teeth.

    Supernumerary teeth.

Tooth Position

    Malpositions: facial/linguoversion, rotations, supra/infra positions, diastemas, other occlusal discrepancies.

Crown Morphology

    Size and shape of crowns.

    Enamel thickness.

    Location of contact points, cemento-enamel junction.

    Racial variations: e.g. shovel-shaped incisors, Carabelli cusp, etc.

Crown Pathology

    Caries.

    Attrition/abrasion/erosion.

    Atypical variations: e.g. peg laterals, fusion/gemination, enamel pearl, multiple cusps.

    Dens in dente.

    Dentigerous cyst.

Root Morphology

    Size, shape, number, dilaceration, divergence of roots.

    Root Pathology

    Root fracture.

    Hypercementosis.

    External root resorption.

    Root hemisections.

Pulp Chamber and Root Canal Morphology

    Size, shape, number.

    Secondary dentin.

    Pulp stones, dystrophic calcification..

    Root canal therapy: e.g. gutta percha, silver points, endo paste and retrofill proce - dures.

    Internal resorption.

    Periapical Pathology.

    Periapical abscess/granuloma/cyst.

    Cementoma.

    Condensing osteitis.

Dental Restorations

    Metallic restorations: amalgams, gold or nonprecious metal crowns/inlays, endo- posts, pins, fixed prostheses, implants.

    Nonmetallic restorations: acrylics, silicates, composites, porcelain, etc.

    Partial and full removal prostheses.

Periodontium

    Gingiva: Morphology/Pathology.

    Contour: gingival recession, focal/ diffuse enlargements, interproximal craters.

    Color: inflammatory changes, physiologic or pathologic pigmentations.

    Plaque and concretions oral hygiene status, stains, calculus.

Periodontal Ligament: Morphology/Pathology

    Thickness.

    Widening (e.g. scleroderma).

    Lateral periodontal cyst.

Alveolar Process and Lamina Dura

    Height/contour/density of crestal bone.

    Thickness of inter-radicular alveolar bone.

    Exostoses, tori.

    Pattern of lamina dura (loss, increased density).

    Periodontal bone loss.

    Trabecular bone pattern osteoporosis, radio-densities.

    Residual root fragments, metallic fragments.

 

Maxilla and Mandible

Maxillary sinuses: Size, shape, retention cyst, antrolith, foreign bodies, oral-antral fistula, relation ship to adjacent teeth.

Anterior nasal spine, incisive canal, median palatal suture, incisive canal: Size, shape, cyst.

Pterygoid hamulus: Size, shape, fracture.

Mandibular canal/mental foramen: Diameter, anomalous (bifurcated), canal, relation ship to adjacent teeth.

Coronoid and condylar process: Size and shape.

Temporomandibular joint:

Size, shape, hypertrophy/atrophy, ankylosis, fracture, arthritic changes.

Other pathologic processes/jaw bones:

Developmental/fissural cysts, hemorrhagic (traumatic) bone cyst, salivary gland depression, reactive/neoplastic lesions, metabolic bone disease, other disorders inducing focal or diffuse radiolucencies or radiopacities, evidence of orthognathic surgery, or prior evidence of trauma (e.g. wire sutures, surgical pins, etc).

 

Categories & Terminology for Body Identification

 

Positive Identification:

The antemortem and postmortem data match in sufficient detail to establish that they are from the same individual. In addition, there are no irreconcilable discrepancies.

 

Possible Identification:

The antemortem and postmortem data have consistent features, but, due to the quality of either the postmortem remains or the antemortem evidence, it is not possible to positively establish dental identification.

 

Insufficient Evidence:

The available information is insufficient to form the basis for a conclusion.

 

Exclusion:

The antemortem and postmortem data are clearly inconsistent. However, it should be understood that identification by exclusion is a valid technique in certain circumstances.

 

NOTE: The forensic dentist is not ordinarily in a position to verify that the antemortem records are correct as to name, date, etc.; therefore, the report should state that the conclusions are based on records which are purported to represent a particular individual.

 

 

 

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Last modified: December 10, 2000