Forensics and diagnostics in orthodontics and maxillofacial surgery

An EVAN Intensive Training course

Toulouse, France,

25th and 26th February 2009

The Department of Biological Anthropology in the University of Toulouse, Paul

Sabatier (UNTO) is a research team in the Faculty of Medicine which is associated with

the Natural History Museum of Toulouse. The Department plays an active role in the

training programs in medicine (3600 students in the first year of medical school) and in

biology (300 students per year).

The department comprises medical doctors and scientists specialising in forensics, genetics,

odontology and palaeoanthropology The department is embedded in a variety of

collaboration in France (e.g., LIRMM in Montpellier, Natural History Museum in Paris) and

overseas (e.g., Transvaal Museum, South Africa) and develops new computer-assisted

methods to analyze skeletal morphology, development for palaeoanthropology, maxillo-facial

surgery, orthodontics, forensics.

This EVAN Intensive Training Course (ITC) will consist of two brief research

reports, and two practical sessions focusing on practical and technical

aspects for the improvement of methods for age assessment and sex

determination from human skeletal remains, from medical computed

tomography (CT) scanners, Cone Beam CT scanners and micro-CT scanners.

Educational object ives:

Participants will be trained in the use of new CT scanners and new methods

for pediatric skeletal age estimation and for sex determination. Research

reports and practical sessions will focus on:

- The use of fully automatic methods for the geometrical analysis and

comparisons of 3D skeletal structures;

- The use and advantages of Cone Beam CT scanners;

- The use of news skeletal collections available in the Forensic

Anthropology Research Centre (South Africa) and in the Institut

d’Anatomie Normale de Strasbourg (France).

Appl ication and registration fees

The total tuition fees for the ITC are 160 euros (€). This covers the classes, a

conference by Professor Michel Brunet, the discoverer of “Toumaï” (25th,

evening), a visit of the newly opened Museum of Natural History in Toulouse

(25th, after lunch), two lunches (25th and 26th of February) and one dinner

(26th), excluding accommodation.

The closing date for applications has been set for 30th January 2009. Interested

candidates are strongly advised to submit their applications by e mail to

braga@cict.fr, as soon as possible, because of the limited number of places

available. Late applications will be considered as far as possible, depending on

the number of places left and the availability of accommodation.

Only application with a payment of application fee of 160 € will be take into

account (Bank: BPOC FONSEGRIVES; ASS INSTITUT PICOT; IBAN: FR76 1780

7000 1901 9195 0749 936; Account #: 01919507499).

Research Report 1

Identification Skeletal Collections, February, 25th, 9:30 - 12:00

Venue: FACULTE DE MEDICINE DE PURPAN - 37 Alles Jules Guesde, Toulouse

Current research: Forensic Anthropology Research Centre (South Africa)

M. Steyn, Department of Anatomy, University of Pretoria

South Africa has a long and proud history of research in Physical Anthropology, and has

excellent, well documented modern skeletal collections that can be used for study. These

collections are still growing, thus reducing problems with secular trends that can influence the

results of studies on older collections. While most research in the past has used basic,

standard anthropological methodology, newer and more advanced techniques have found its

way into our research. Current projects involve, amongst others, the use of geometric

morphometrics to study sexual dimorphism and ontogeny (e.g, development of the scapula,

growth of faces). However, we have participated only in two-dimensional analyses, which

need to be expanded to include 3-D capability. Bone histological analyses have included age

estimation and differentiation between human and animal bones, but micro-CT scanning

provides exciting new opportunities for age determination of, for example, bone trabeculae. A

recent advancement include one PhD project in which bite force transmission in prognathic

and non-prognathic skulls will be compared by means of finite element analysis. We are also

looking towards improving methodology used in skull-photo superimposition by using threedimensional

surface scanned images of the skull, in order to help sort out problems with

aligning photographs and skulls. It is difficult for any one researcher to keep up with all

possible modern techniques that become available, thus paving the way for future more

intense collaboration between skeletal biologists and various other experts such as engineers

and mathematicians.

Current collaborat ion with the Inst itut d’ Ana t omi e Norma le d e St ra s bour g

(France)

J. Braga, Department of Biological Anthropology, University of Toulouse

The human skeletal collection in the Institut d’Anatomie Normale de Strasbourg consists

entirely of young individuals who passed away in the late 19° and early 20° centuries. A few

institutions in Europe have as large a collection of human skeletal remains with such well

known age and sex data. The Department of Biological Anthropology in Toulouse has started a

research collaboration with the Institut d’Anatomie Normale de Strasbourg. This current

collaboration will be presented.

For the geometrical analysis and comparisons of 3D skeletal structures, some

researchers have proposed to use directly 3D feature curves which give much

more information than sparse points. However, it can be difficult to define

manually these curves and the result remains user-dependent. So, some

researchers in computer science have developed methods to extract

automatically such kind of curves (often called “crest” or “ridge” lines) from a

3D image and they have used them to analyse the shape of a bone or a tooth.

They have also showed that crest lines are very close from anatomical lines

which are extracted under the supervision of an expert. We present the latest

algorithms to compute fully automatically crest lines and we apply them on

several anatomical structures (tooth, skull, endocranium) of a database of CTScan

and microCT-Scan. We show how these lines emphasize the bony or dental

structures and can subsequently be applied to the problems of age and/or sex

determination.

Participants will also be shown how to align automatically two surfaces

(polygonal models) with the minimal distance between them and without any

prior choice on its topology, i.e. without any selection of a specific landmark

which may influence the results.

Practical Session 2

Cone beam CT scanners versus Medical CT scanners, February 26th, 9:30 - 12:00

Venue: FACULTE DE CHIRURGIE DENTAIRE, 118 Route de Narbonne, Toulouse

[Main Instructor : Dr Delphine

MARET (Dentist) and Dr

Jacques TREIL (Radiologist)

Department of Biological

Anthropology, University of

Toulouse

The compact size and relatively low radiation dosage of the Cone Beam Computed

Tomography scanner makes it ideally suited for imaging the craniofacial region, including

dental structures. With the increasing accessibility of Cone Beam CT imaging, this modality is

emerging as an important new imaging standard for the diagnostic assessments of the bony

and dental components of the face. In contrast to the classical CT scanner, the cone beam CT

scanner does not image slices, instead its cone shaped beam illuminates a complete volume at

once.

The Cone Beam CT combines the advantages (among others) of producing true isotropic

voxels at a significantly higher spatial resolution (i.e. smaller voxels) than medical CT

scannesr, of being very easy to operate and to maintain (little technician training is required),

of a radiation dose is considerably less than with a medical CT.

Volumetric measurements taken on dental tissues with a Cone Beam CT and a micro-CT will

be presented. Perspectives will be discussed.

Research Report 2

Identification Age and Sex, February 26th, 15:00 - 17:30

Venue: FACULTE DE MEDICINE DE PURPAN - 37 Alles Jules Guesde, Toulouse

Pediatric skeletal age using the skull

J. Braga, Department of Biological Anthropology, University of Toulouse

The purpose of this investigation is, first, to increase the variety of age-related

structures theoretically available for pediatric skeletal age estimation and,

second, to devise a method that can be applicable from early postnatal age to the

end of adolescence with a satisfactory accuracy independent of age. With the aid

of cross-validations, the centroïd size of the facial skeleton can be used an agerelated

variable without any loss of accuracy with increased age, contrary to

most of the methods of pediatric age estimation. However, this study was done by

using simply 3D landmarks. This new research focuses on size and shape changes

on the facial skeleton with the use of polygonal models rather than landmarks or

semi-landmarks. The following questions will be addressed: (i) where and when

do we observe on the facial skeleton the most significant changes in size and

shape? (ii) how can we devise a method for age estimation from these

observations in order to be reliable, precise for both early and late juveniles?

Averaging the sexual dimorphism of the 3D architecture of the

pelvis

M Faruch, N Telmon; F Dedouit, J. Braga, Department of Biological Anthropology,

University of Toulouse

This research proposes to apply new tools for the analysis of sexual variations of

the pelvic bone in human populations. The best methods for sex determination

from adult skeletal remains involve measurements and visual inspection of the

pelvic bone that presents a number of well-known, gender-related morphological

differences. However, the major problems for sex determination are that the

pelvic bone might be incomplete, or might belong to adolescent individuals.

Moreover, there is still a controversy about some anatomical definitions of

landmarks and the applicability of the same method by different observers. The

purpose of this investigation is to devise an automatic method for sex

determination from the analysis of 3D polygonal models of the pelvic bone. Can

we find comparable, common trends, by using skeletal samples representing

human populations of different geographic origins.

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