SEM of interproximal groove indicative of therapeutic practice

at Pete Klunk Mounds, IllinoisSavannah Leach

Indiana University Bloomington, Department of Anthropology

Acknowledgments

Scanning Electron Microscopy

11-C40-38Introduction

References

Results and ConclusionINTERPROXIMAL GROOVES

Interproximal grooves are smooth and frequently polished indentations found

between adjacent teeth. They are cylindrical in shape and are often characterized

by their sharp margins and parallel striations along its interior running bucco-

lingually. They are most commonly found near the cemento-enamel junction

(CEJ).1,2,3,4, Interproximal grooves have multiple etiologies1,5, which include:

• Picking with a dental probe

• Habitual

• Therapeutic

• Abrasive dietary components being consistently sucked through

the teeth

• Using teeth as tools

• Antemortem chemical erosion

Population based studies have found incidence rates as high as 8.9%.

American Indian populations have recorded incidences as high as 1.6%1. Most of

these grooves are found on the mesial or distal surfaces and are most frequently

found in the maxillary posterior teeth.1,3 Some evidence shows a male bias.3

Turner and Cacciatore found that 9.8% of their samples had interproximal

grooving associated with carious lesions.1 Ubelaker and colleagues found that

92.31% of the 26 American Indian Individuals also display alveolar resorption near

the location of the interproximal groove and 36.56% of the teeth with interproximal

grooves are associate with interproximal caries, with the buccal edge being more

definitively grooved.2

The scanning electron micrographs (SEM) presented here will provide some

insights into the etiology of the interproximal groove of a Middle Woodland

individual from Pete Klunk Mounds in Calhoun County, Illinois.

PETE KLUNK MOUND GROUP

Gregory Perino began excavation on the Pete Klunk Mound Group in the

field season of 1960 and it was completed the following year. Of the three mound

groups in Kampsville, Illinois, Pete Klunk Mound Group is the largest and is

located on the bluff north of town. The mounds, 14 in total, run north-south along

the bluff overlooking the Illinois River. The site is primarily Middle and Late

Woodland components, but there is also a minor Archaic portion, including an

Archaic charnel pit and a small portion of Mound 7.6

Scanning electron microscopy (SEM) works by using electrons, instead of

light, to form an image. A beam of electrons is sent from the top of the microscope

to the sample, located in a vacuum sealed chamber. The electrons hit the sample

and are then ejected and collected by detectors, which change the x-rays and

electrons into a signal that can be turned into a final image. All non-metal materials

are covered in a conductive material to create a clearer image.7

Scanning electron micrographs were obtained with the help of Barry Stein

at the Electron Spectroscopy Center at Indiana University, Bloomington. The molar

was sputter coated with approximately 45 nm of platinum using a Polaron SEM

E5100 Coating Unit. Once sputter coated, the scanning electron micrographs were

captured with a JEOL JSM-5800 LV, which has magnifications ranging from 18x to

300,000x and voltages from 0.3 to 30 kV.

1. Turner, CG and E Cacciatore. 1998. Interproximal Tooth Grooves in Pacific Basin, East Asian and New

World Populations. Anthropological Science. 106: 85-94

2. Ubelaker, DH, RW Phenice, and WM Bass. 1969. Artificial Interproximal Grooving of the Teeth in

American Indians. Am J Phys Anthropo 30:145-150

3. Luckacs, JR and RF Pastor. 1988. Activity-Induced Patterns of Dental Abrasion in Prehistoric Pakistan:

Evidence from Mehrgarh and Harappa. Am J Phys Anthropo 76:377-398

4. Formicola, V. 1991. Interproximal Grooving: Different Appearances, Different Etiologies. Am J Phys

Anthropo 86: 85-87

5. Berryman, HE, DW Owsley and AM Henderson. 1979. Non-carious Interproximal Grooves in Arikara

Indian Dentitions. Am J Phys Anthropo. 50:209-212

6.. Perino, G. 1968. The Pete Klunk Mound Group, Calhoun County, Illinois: The Archaic and Hopewell

Occupations. In: Hopewell and Woodland Site Archaeology in Illinois. Bulletin 6. Illinois

Archaeological Survey, Urbana. pp. 9-124

7. Purdue University. 2014. Radiological and Environmental Management: Scanning Electron Microscope.

Retrieved: 3/5/2015. http://www.purdue.edu/ehps/rem/rs/sem.htm

8. Stein, Barry. Personal Communication. IU Electron Microscopy Center

I would like to thank Berry Stein and the Electron Microscopy Center at Indiana

University Bloomington for assisting me with sputter coating and imaging. I would also

like to thank Della Cook for advice and feedback. Thank you to Lita Sacks, Paige Wojcik

and Olof Olafardottir for poster advice.

Buccal

Oc

clu

sa

l

Lingual

11-C40-3811-C40-38 is an older adult male (>50 years old) from Mound 11. Mound 11

is part of the Middle Woodland component of the site and is situated at the highest

point of the crest. This individual was extended in a subfloor burial found on the

outside of the mound.6 The interproximal groove is located on the distal side of the

2nd right maxillary molar along the CEJ. There is a caries located on the lingual

edge of the groove in the cervical region. The groove is approximately 2.5 mm

wide at the center and approximately 5 mm long. There is only a slight indentation

on the third right maxillary molar, which could not be successfully photographed.

The only dental pathology outside of this interproximal groove is the

associated caries on the effected tooth and some minor bone resorption. No other

individuals in the Middle Woodland component of the site have similar grooves.

Future Research

o The interproximal groove shows expected characteristics described in

previous work

o Macroscopic inspection shows the groove has a curvilinear

outline, which suggests the insertion of a cylindrical object

o Sharp edges can be seen in both the macroscopic examination

and in the SEM. The SEM appears lighter around these sharp

edges due to the Edge Effect (Micrograph B)

o The Edge Effect is a result of many secondary

electrons being emitted through the uneven surface8

o The interproximal groove is located at the CEJ

o The most frequently documented location of interproximal

grooves is on maxillary posterior teeth, as seen here1

o The SEM shows parallel striations along the interior of the groove

(as indicated by the red arrows; Micrograph C and D)

o Suggest abrasion and not chemical erosion as the

causative process5

o These striations run bucco-lingually

o The non-perpendicular angle of insertion suggests the use of a

non flexible tool during life

o The best explanation for this groove is the dental probe hypothesis

o No other members of this Middle Woodland population have

interproximal grooves

o Not likely the result of abrasive diet alone

o Not likely from tool use (such as from processing

sinew)

o Habitual or Therapeutic?

o The location of the interproximal caries at the lingual

edge of the groove suggests therapeutic probing

(Macroscopic Images and Micrograph A)

o The caries would have likely caused

regular pain

o Massaging the area and surrounding

gingiva with a tool may have helped to

alleviate some of this discomfort

The next steps in this project include:

• Use experimental archaeology to determine material used as the

dental probe

• Investigate the individuals from other components of the Pete Klunk

Mound group

• Investigate other surrounding mound groups of Kampsville, Illinois

A B

C D