3 results
10 - “Mineral Maintenance” of dental structures in caries and erosive tooth wear: an holistic model
-
- By John Kaidonis, The University of Adelaide, Australia, Sarbin Ranjitkar, The University of Adelaide, Australia, Grant Townsend, The University of Adelaide, Australia
- Edited by Grant Townsend, University of Adelaide, Eisaku Kanazawa, Nihon University, Japan, Hiroshi Takayama, Keio University, Japan
-
- Book:
- New Directions in Dental Anthropology
- Published by:
- The University of Adelaide Press
- Published online:
- 05 May 2013
- Print publication:
- 01 June 2012, pp 115-122
-
- Chapter
- Export citation
-
Summary
ABSTRACT
It is argued that dental structures within the oral environment have evolved with an ability to resist dissolution when exposed to acidic conditions, and to promote remineralisation after damage has occurred. It is hypothesised that dietary acids acted as one of the selective forces in the evolution of the oral environment. It appears that a balance was achieved in hunter-gatherer populations, with the composition and action of saliva, and associated oral biofilms, evolving to protect the teeth against dietary acids. However, in the relatively short period of time since the development of farming and especially with the adoption of modern cultural practices, changes in diet have overwhelmed the oral environment, creating an imbalance. In general, the vast increase in consumption of acidic foods and drinks has decreased the protective mechanisms of saliva. Similarly, the increased consumption of sugar has changed the ecology of oral biofilms, leading to and maintaining a lower oral pH. A combination of these factors has tipped the balance towards demineralisation and increased the risk of oral diseases, such as dental caries and erosive wear, that are so prevalent in many of today's societies.
INTRODUCTION
The Paleolithic, stone age or hunter-gatherer way of life, covers a period of over 2.5 million years of hominin evolution, culminating with the appearance of modern Homo sapiens over 200,000 years ago. This period demonstrates the most basic technological developments including the use of the most primitive stone tools (Toth and Schick, 2007).
11 - Emerging techniques for the analysis of tooth wear
-
- By Sarbin Ranjitkar, The University of Adelaide, Australia, John Kaidonis, The University of Adelaide, Australia, Colin Hall, The University of Adelaide, Australia, Victor Marino, The University of Adelaide, Australia, Lindsay Richards, The University of Adelaide, Australia, Grant Townsend, The University of Adelaide, Australia
- Edited by Grant Townsend, University of Adelaide, Eisaku Kanazawa, Nihon University, Japan, Hiroshi Takayama, Keio University, Japan
-
- Book:
- New Directions in Dental Anthropology
- Published by:
- The University of Adelaide Press
- Published online:
- 05 May 2013
- Print publication:
- 01 June 2012, pp 123-138
-
- Chapter
- Export citation
-
Summary
ABSTRACT
Changing patterns of tooth wear have been used extensively to obtain information about the lifestyle and culture of pre-historic and modern humans. The assessment of tooth wear in previous anthropological studies has been largely based on quantitative analysis of wear indices and qualitative analysis of micrographs. Wear indices are simple to use and can be sensitive tools, but there is a lack of international standardization in their use. Micrographic assessment of pits and scratch marks on the worn surfaces of teeth can assist in dietary reconstruction of humans, but this approach has low reliability and high observer error. This review will provide an update on a new wear index and novel nano-techniques that hold promise for improving the analysis of tooth wear. Recently, a new wear index, termed the Basic Erosive Wear Examination index, has been proposed as a standardized universal tool for diagnosing erosive tooth wear. However, its value seems to be limited when assessing the dentitions of populations, in whom tooth wear occurs predominantly by attrition and abrasion. Optical techniques involving scanning confocal microscopy combined with fractal analysis can provide an objective assessment of the worn surface. Other nanotechnology-based methods, such as nanohardness measurements, nano-computed tomography and mass spectrometry, can be also useful in physical and chemical characterization of both sound and worn teeth, but these techniques are limited to use in vitro. A combined assessment of the worn dentition using all of these techniques promises to provide the best holistic approach to analyse tooth wear.
6 - Dental crown and arch size in Europeans and Australian Aboriginals
-
- By Atika Ashar, The University of Adelaide, Australia, Toby Hughes, The University of Adelaide, Australia, Helen James, The University of Adelaide, Australia, John Kaidonis, The University of Adelaide, Australia, Fadhli Khamis, Universiti Sains Malaysia, Health Campus 16150 Kubang Kerian, Kelantan, Malaysia, Grant Townsend, The University of Adelaide, Australia
- Edited by Grant Townsend, University of Adelaide, Eisaku Kanazawa, Nihon University, Japan, Hiroshi Takayama, Keio University, Japan
-
- Book:
- New Directions in Dental Anthropology
- Published by:
- The University of Adelaide Press
- Published online:
- 05 May 2013
- Print publication:
- 01 June 2012, pp 65-80
-
- Chapter
- Export citation
-
Summary
ABSTRACT
Various methods have been used to measure human dental crown and arch size as a means of examining population affinities and differences. Traditionally, this has been done using hand-held calipers, however, new technology such as two dimensional and three dimensional imaging now provide alternatives for researchers. Here, we report the findings of a study to validate two new imaging techniques (2D and 3D) and to quantify differences in the dentitions of several human populations for whom dental records are available. 2D photographic imaging using a digital SLR (Canon Inc, Tokyo, Japan), and 3D laser scanning with an Optix 400S 3D laser scanner (3D DigitalCorp, Connecticut, USA) were utilized. Measurements of dental crown variables, including mesiodistal and buccolingual dimensions and interarch widths, were explored statistically. Data extracted using both 2D and 3D techniques were compared to assess the precision and accuracy of the two methods. Both 2D and 3D techniques displayed high levels of precision and accuracy, and highlighted statistically significant differences in dental crown size and arch size within and between the study populations. The methods developed offer considerable promise for the field of forensic odontology, including distinguishing individuals within populations on the basis of their dentitions.
INTRODUCTION
Many dental anthropologists have focused on non-metric traits to characterise major population groups (Hanihara, 1967; Scott and Turner, 1997), and various ‘dental complexes’ have been identified, including Mongoloid, Caucasoid, Negroid and Australoid (Turner, 1990; Townsend et al., 1990; Mayhall et al., 1999). In conjunction with non-metric traits, there have also been numerous metric studies of the dentitions of human populations (Hanihara, 1998; Falk and Corruccini, 1982; Kieser, 1991; Hanihara and Ishida, 2005). Based on these studies, populations have been grouped as microdontic, mesodontic, and megadontic (Hanihara and Ishida, 2005). Some researchers have claimed that non-metric qualitative characteristics are more useful than continuously variable quantitative characteristics in grouping people according to their geographic location and affinities (Lasker and Lee, 1957; Hanihara, 2008). Measurements of dental crown size and arch size, however, provide greater objectivity than scoring of traits. A combination of metric and non-metric features is likely to provide the most comprehensive and discriminatory description of human dentitions.