Oral Presentation performed at the SkyScan User Meeting 2011 in Leuven, Belgium.

1. Thank you very much. It is an honor to be here with you today. I would like to thank
SkyScan for this invitation and to the University of São Paulo in the person of Prof.
Manoel for the oportunity to be here.
1

2. An old and fascinating human practice, body ornamentation can be achieved through
a variety of means including clothing, piercings, tattooing, scarification, dental
modification, among others.
2

3. Artificial dental modification is found in many areas of the world ….
3

4. ….but is best known in the ancient civilization of Mesoamerica. The Mayas were a
people with a highly developed culture who inhabited the Yucatan Peninsula. The
nation's history began about 2500 B.C., but the culture flourished from about 300
A.D. to about 900 A.D.
4

5. In their dental practiced, teeth were drilled with small holes to permit the insertion of
round pieces of stone.
5

6. The filing procedure was employed using a hard tube that was spun between the
hands or in a rope drill, with a slurry of powdered quartz in water as an abrasive, to
cut a hole through the enamel of the tooth.
6

7. Then, the inlay was cemented into place.
7

8. Although many studies involve description and classification of artificially modified
teeth, few examine the consequences of this modification.
8

9. The aim of this study was to evaluate three-dimensionally the anatomical relationship
between the cavity prepared to hold the inlay stone and the pulp chamber in six well-
preserved Maya's teeth found in an archaeological site in Guatemala, with
approximately 1600-year-old.
9

10. Each specimen was vertically positioned on a metal holder in the center of the stage
and scanned in a desktop X-ray microfocus CT scanner SkyScan 1174v2 using the
following parameters:
10

11. Images of each specimen were reconstructed from apex to the coronal level with
NRecon software which provided axial cross sections of the inner structure of the
samples in approximately 450 slices.
11

12. Ctan and CTVol software were used for the three-dimensional visualization and
qualitative analysis of the external and internal anatomy of the teeth
12

13. A tooth is basically made up of two parts: the crown and the root. Different tissues
make up each tooth: the enamel, the dentin, that supports the enamel, and the pulp
that is a soft tissue located within a tooth, in a place called pulp cavity that is divided
into root canal and pulp chamber.
13

14. In a situation that a tooth is considered so threatened and infection of the root canal
space is considered inevitable, the removal of the pulp tissue is advisable to prevent
such infection that could lead to necrosis, calcification or internal resorption.
14

15. In ancient Mesoamerica civilizations, non-therapeutic dental modification was a
distinguishing mark of high status, of belonging to a tribe or clan, or of beauty. In
Maya's culture, alteration of the crown contour was the most common form of dental
modification, followed by inlays or incrustations. Dental modification was found
predominantly in the anterior teeth. The types of stones used for inlay vary
geographically and temporally but include pyrite, jade, turquoise, jadeite, hematite,
and obsidian
15

16. Despite a complete classification of artificial modifications to human teeth has been
performed by some authors, in the present study it was used the classification system
created by Romero Molina (1970) because it constitutes the Mesoamerican standard
for categorization.
Romero defined seven basic types of dental modifications based on the study of a
collection of 1,212 teeth. Each type was subdivided into at least five variants,
resulting in a total of 59 different types. According to Romero’s classification, the
dental modification of all specimens in the present study was classified as type E1
(one stone on the buccal surface of the crown), except one lateral incisor that was E2
(two stones on the buccal surface of the crown).
16

17. Now, I am going to present you the three-dimensional reconstruction of the Maya’s
teeth. In the canine teeth, the holes made to insert the inlay stone did not reach the
pulp chamber.
17

18. It probably happened because of the thickness of enamel compared to the other
teeth.
18

19. In the premolar tooth only a small perforation of the pulp chamber under the buccal
cusp, without morphological alteration of the intraradicular dentine, was observed.
19

20. Multiple levels of responses and interactions occur in reaction to mechanical injuries
of the dental pulp. Depending on the severity and duration of the insult and the host
response, two distinct hard tissue changes may be induced: resorption or
calcification. In the maxillary incisors, it was observed that the holes clearly
perforated the pulp chamber resulting in a massive internal inflammatory resorption.
20

21. 21

22. and partial calcification of the pulp cavity.
22

23. 23

24. The intentional modifications of human teeth hold anthropological and social
significance. Their study helps to understand past and present human behaviour from
a geographic, cultural, religious, and aesthetic perspective. Micro-computed
tomography analysis of ancient Maya's teeth showed that the holes made to insert
the inlay stone reach the pulp chamber in the maxillary incisors and premolar teeth.
In the incisors, it was observed the development of internal resorption and
calcification. Intraradicular dentine and pulp cavity of canines and premolar teeth
showed no morphological alteration. To our knowledge, this is the first study of
modified Maya’s teeth using micro-computed tomography and opens a perspective
for further research on the understanding of pulpal and/or periradicular pathosis in
ancient civilizations.
24

25. 25