Evidence of pulp disease in the inlayed teeth of the
ancient Mayans: a micro-CT study
M. A. Versiani1, J. D. Pécora1, M. D. Sousa-Neto1
1
Department of Restorative Dentistry, Faculty of Dentistry, University of São Paulo, Avenida
do Café s/n, Ribeirão Preto, São Paulo, Brazil, CEP 14040-904
Aims
Root canals and their associated pulp chamber are the physical hollows within a tooth
that are naturally inhabited by nerve tissue, blood vessels and other cellular entities, named
pulp tissue. 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. Calcification is
considered as the hardening of decaying of dead soft tissue represented by calcified nodules
or amorphous deposits in the pulp, and the internal resorption as a condition when the
dentine and pulpal walls begin to resorb centrally within the root canal1.
An old and fascinating human practice, body ornamentation can be achieved through
a variety of means including clothing, piercings, tattooing, and scarification, among others.
Another such method, artificial dental modification, is found in many areas of the world but is
perhaps best known in Mesoamerica. The Mayas were a peaceful 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. In their dental
practiced, teeth were filed into points, ground into rectangles and drilled with small holes to
permit the insertion of small round pieces of stone in over a hundred different patterns2. 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
tooth enamel. Then, the inlay was cemented into place. The stone inlay was ground to fit the
cavity so precisely and the plant adhesive was so powerful that many have remained in the
teeth for thousands of years2,3. Although many studies involve description and classification
of artificially modified teeth, few examine the consequences of this modification. Previous Xray and scanning electron microscopy analysis have shown that most of the time the holes
reached the dentine and even the pulp cavity2,4-6. However, to date no study demonstrated
the three-dimensional relationship between the tooth inlay and the pulp cavity in Mayan's
teeth.
The aims of the present study were to evaluate qualitatively the relationship between
the inlay and the pulp cavity, and its influence within the pulp canal space, in ancient Mayan's
teeth, using microcomputed tomography technique.
Method
Six well-preserved Mayan's teeth from Guatemala with approximately 1600 years old,
donated by a private collector, presenting alteration of the labial surface of the crown with
inlays of jade or hematite, classified as types E1 (one stone at the labial surface) and E2 (two
stones at the labial surface)7 were selected for this study. SkyScan 1074 (SkyScan, Kontich,
Belgium) high-resolution micro-CT scanner was used to scan the teeth. The system
consisted of a sealed air-cooled X-ray tube, 20-50 kV / 40W / 800 µA, with a precision object
manipulator with two translations and one rotation direction. The system also included a 14bit CCD-camera based on a 1.3 Megapixel (1304 x 1024 pixels) CCD-sensor. Each tooth
was vertically positioned on a metal holder in the center of the specimen stage and scanned
(50 kV, 800 µA) with a pixel size of 22.5 µm, rotational step of 0.70 degree, rotational angle
of 180 degrees, and a 3.1-second exposure time, using a 1-mm-thick aluminum filter. With
the NRecon version 1.6.3 (Skyscan) software, images obtained from the scan were
reconstructed to show 2-dimensional (2D) slices of the inner structure of the teeth. Finally,
the CTan version 1.11 and CTVol version 2.1 (Skyscan) softwares were used for the 3dimensional (3D) volumetric visualization and qualitative analysis of the canal space
assessed by an expert observer.
Results
The filing of the all analyzed teeth was of type E1 (Figures 1 to 5) except the lateral
upper incisor that was type E2 (Figure 6). It is interesting to note that teeth with a thicker
enamel layer, as canines and premolar (Figures 1 to 3), did not present significant alteration
in the canal space, as pulp tissue was not injured. The interior anatomy of the root canal
space and dentine are clearly visible in these teeth. On the other hand, the central and lateral
incisors (Figures 4 to 6) showed that the cavities created to insert the inlay stones perforated
the pulp chamber, resulting in an irreversible inflammatory reaction of pulp tissue leading to a
massive internal resorption (Figures 4 and 5) and calcification of the pulp tissue (Figure 6).
Figure 1: Right upper canine. 3D reconstruction in a frontal and lateral
views of the external (a, b) and internal (c, d) anatomy of the teeth and the
pulp canal space (e, f). Transversal (g, h) and axial (i, j, k) cut showing
pulp canal space and dentine without evidence of disease [green arrow:
dental inlay (hematite)].
Figure 2: Right upper first premolar. 3D reconstruction in a frontal and
lateral views of the external (a, b) and internal (c, d) anatomy of the teeth
and the pulp canal space (e, f). Transversal (g, h) and axial (i, j, k) cut
showing pulp canal space and dentine without evidence of disease [green
arrow: dental inlay (jade)].
Figure 3: Right upper canine. 3D reconstruction in a frontal and lateral
views of the external (a, b) and internal (c, d) anatomy of the teeth and the
pulp canal space (e, f). Transversal (g, h) and axial (i, j, k) cut showing
pulp canal space and dentine without evidence of disease [green arrow:
dental inlay (jade)].
Figure 4: Left upper central incisor. 3D reconstruction in a frontal and
lateral views of the external (a, b) and internal (c, d) anatomy of the teeth
and the pulp canal space (e, f). Transversal (g, h) and axial (i, j, k) cut
showing pulp canal space and dentine with evidence of disease [red
arrow: internal resorption; green arrow: dental inlay (hematite)].
Figure 5: Left upper central incisor. 3D reconstruction in a frontal and
lateral views of the external (a, b) and internal (c, d) anatomy of the teeth
and the pulp canal space (e, f). Transversal (g, h) and axial (i, j, k) cut
showing pulp canal space and dentine with evidence of disease [red
arrow: internal resorption; green arrow: dental inlay (hematite)].
Figure 6: Right upper lateral incisor. 3D reconstruction in a frontal and
lateral views of the external (a, b) and internal (c, d) anatomy of the teeth
and the pulp canal space (e, f). Transversal (g, h) and axial (i, j, k) cut
showing pulp canal space and dentine with evidence of disease [red
arrow: calcification; green arrow: dental inlay (jade)].
Conclusion
Considering the limitations of the present study, micro-CT analysis of ancient Mayan's
teeth allowed to observe tridimensionally the anatomical relationship between the bottom of
the artificial cavity prepared to hold an inlay, and the pulp chamber, evidencing a perforation
of a depth of approximately 1.5 mm deep, with parallel walls and a convexly shaped basis
only in the incisors. In these teeth, the pulpal response was readily detectable with the
presence of internal resorption and calcification.
References:
1. Hargreaves KM, Cohen S, "Cohen's Pathways of the Pulp", Mosby Elsevier, 2010.
2. Whittington SL, Reed DM, "Bones of the Maya: Studies of Ancient Skeletons",
University of Alabama Press, 2006.
3. Romero-Vargas S, Ruiz-Sandoval JL, Sotomayor-González A, Revuelta-Gutiérrez R,
Celis-López MA, Gómez-Amador JL, García-González U, López-Serna R, GarcíaNavarro V, Mendez-Rosito D, Correa-Correa V, Gómez-Llata S, "A look at Mayan
artificial cranial deformation practices: morphological and cultural aspects",
Neurosurg Focus, 6, E2, 2010.
4. Gwinnett AJ, Gorelick L, "Inlayed teeth of ancient Mayans: a tribological study using
the SEM", Scan Electron Microsc, 2, 575-80, 1979.
5. McKillop HI, "The ancient Maya: new perspectives", ABC-CLIO, 2004.
6. González EL, Pérez BP, Sánchez JA, Acinas MM, "Dental aesthetics as an
expression of culture and ritual", Brit Dent J, 2, 77-80, 2010.
7. Romero J, "Dental Mutilation, Trephination, and Cranial Deformation", University of
Texas Press, 1970.