1,720,979 research outputs found
Glypican-based drug releasing titania implants to regulate BMP2 bioactivity as a potential approach for craniosynostosis therapy
No full textResearch Article Special Topic: Two-Dimensional Biomaterials in Regenerative MedicineAbstract not availableManpreet Bariana, Prem Dwivedi, Sarbin Ranjitkar, John A. Kaidonis, Dusan Losic, Peter J. Anderso
Prevention of tooth erosion and sensitivity in wine tasters
No full textSarbin Ranjitkar, Roger Smales and Dimitra Lekka
An anthropological perspective: Another dimension to modern dental wear concepts
Get PDFExtent: 6p.For many years, research on tooth wear by dental academics has been diametrically opposite to that of anthropological research, with each discipline having a different understanding as to the nature of the wear processes. Dental focus revolved around preventive and restorative considerations while the anthropological focus was a biological understanding related to human evolution, diet, environment, form, and function and included all the craniofacial structures. Introducing the anthropological perspective into modern dentistry gives an insight into the “bigger picture” of the nature and extent of tooth wear. By combining anthropological evidence with clinical knowledge and experience, it is most likely to provide the best-informed and biologically based approach to the management of tooth wear in modern societies.John A. Kaidonis, Sarbin Ranjitkar, Dimitra Lekkas, and Grant C. Townsen
'Mineral maintenance' of dental structures in caries and erosive tooth wear: an holistic model
No full textit 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 occured. It is hypothesised that dietry acids acted as one of the selected 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 protec the teeth against dietry 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 icreased the risk of oral diseases, such as dental caries and erosive wear, that are prevalent in many of today's societies.John Kaidonis, Sarbin Ranjitkar and Grant Townsen
Three-dimensional profilometric assessment of early enamel erosion simulating gastric regurgitation
No full textAbstract not availableChelsea Mann, Sarbin Ranjitkar, Dimitra Lekkas, Colin Hall, John A. Kaidonis, Grant C. Townsend, Alan H. Broo
A system for the acquisition and analysis of three-dimensional data describing dental morphology
Get PDFCopyright © 2004 Dental Anthropology AssociationAccurate, reproducible three-dimensional (3D) data provide an important contribution to our ability to describe, compare and understand dental morphology but the existing technology is often expensive or has technical limitations. Recently available, inexpensive 3D profilometers interfaced with standard personal computers offer the potential to overcome some of these problems. This technical note describes a system that uses a 3D profilometer and purpose written software to analyse changes in dental morphology resulting from tooth wear. The validity of the derived data was determined by comparing data derived from scans of objects of known dimensions with calculated volumes. These differences were less than 10% from objects that were difficult to scan because of their geometry and were commonly less than 5%. The reproductibility, expressed as intra- and inter-observer coefficients of variation, was less than 1%. The potential applications of systems of this type are outlined.Pingzhou Liu, Sarbin Ranjitkar, John A. Kaidonis, Grant C. Townsend, and Lindsay C. Richardshttp://anthropology.osu.edu/DAA/dentalanthropologyjournal.ht
Tooth wear development in the Australian Aboriginal dentition from Yuendumu: a longitudinal study
Get PDFThe analysis of dental wear, at both the microscopic and macroscopic scale, is one of the most widely used tools in archeology and anthropology to reconstruct the diet and lifestyle of past human populations. Biomechanical studies have indicated that tooth wear helps to dissipate the mechanical load over the crown surface, thus reducing the risk of tooth fracture. To date, there are only a few studies that have examined functional tooth wear variation in modern humans. Here we propose to study masticatory efficiency through the use of the Occlusal Fingerprint Analysis method, a well-developed digital approach that allows the reconstruction of the occlusal dynamics occurring during mastication. The aim of this study is to provide the first longitudinal quantitative data of molar and premolar macrowear patterns within a functional context. We examined the mixed and permanent dentition of one Australian Aboriginal child (from ages 8 to 17) from Yuendumu, using high-resolution surface scans of dental casts including both upper and lower arches. Our results suggest that the occlusal macrowear patterns of this individual did not significantly change through time. Occlusal contact parameters such as functional area, inclination and direction remain relatively unaltered throughout childhood and adolescence, indicating little change in the masticatory function of this individual. The functional tooth wear pattern in this individual did not change longitudinally indicating the degree of masticatory efficiency has most probably remained unaltered.Jinyoung Lee, Sarah Fung, Robin Yong, Sarbin Ranjitkar, John Kaidonis, Alistair R. Evans, Luca Fiorenz
Extensive phenotyping of the orofacial and dental complex in Crouzon syndrome
No full textObjectives: Fibroblast growth factor receptor 2 (FGFR2) C342Y/+ mutation is a known cause of Crouzon syndrome that is characterised by craniosynostosis and midfacial hypoplasia. Our aim was to conduct extensive phenotyping of the maxillary, mandibular and dental morphology associated with this mutation. Materials and methods: Morphometric data were obtained from 40 mice, representing two genotypes (Crouzon and wild-type) and two sexes (males and females) (n=10 in each group). Dental analysis further categorised the first molars into the two jaws (maxillary and mandibular) (n=20 in each group). Maxillary, mandibular and dental morphology was compared by analysing 23 linear landmark-based dimensions in three-dimensional micro-computed tomography reconstructions. Results: Compared with wild-type, Crouzon (FGFR2C342Y/+) maxillae were significantly shorter in maximum height, anterior and posterior lengths and middle width, but larger in posterior width (p<0.05 for height; p<0.001 for other comparisons). In the Crouzon mandible, the ascending and descending heights, effective and mandibular lengths, and intercoronoid and intercondylar widths were significantly shorter, whereas intergonial width was larger (p<0.01 for intercondylar width; p<0.001 for other comparisons). Crouzon teeth were significantly smaller mesiodistally, but larger in crown height (p<0.001 for each comparison). All Crouzon mice presented with bifid mandibular condyles and a quarter presented with expansive bone lesions in the mandibular incisor alveolus. Conclusions: Our findings of hypoplasia in all three planes in Crouzon maxillae and mandibles, together with the presence of bifid mandibular condyles and expansive bone lesions, may be relevant to maxillofacial surgery and orthodontics. Beyond skeletal effects, the FGFR2C342Y/+ mutation is now implicated in affecting tooth development. This study's skeletal phenomics data also provides baseline data against which the effect of various treatments can now be assessed.Alexander Khominsky, Robin Yong, Sarbin Ranjitkar, Grant Townsend, Peter J. Anderso
Three‐dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations
No full textObjectives: This study aimed to investigate size and shape variation of human premolars between Indigenous Australians and Australians of European ancestry, and to assess whether sex and ancestry could be differentiated between these groups using 3D geometric morphometrics. Materials and Methods: Seventy dental casts from each group, equally subdivided by sex, were scanned using a structured-light scanner. The 3D meshes of upper and lower premolars were processed using geometric morphometric methods. Seventy-two landmarks were recorded for upper premolars and 50 landmarks for lower premolars. For each tooth type, two-way ANOVA was used to assess group differences in centroid size. Shape variations were explored using principal component analysis and visualized using 3D morphing. Two-way Procrustes ANOVA was applied to test group differences for ancestry and sex, and a “leave-one-out” discriminant function was applied to assess group assignment. Results: Centroid size and shape did not display significant difference between the sexes. Centroid size was larger in Indigenous Australians for upper premolars and lower second premolars compared to the Australians of European ancestry. Significant shape variation was noted between the two ancestral groups for upper premolars and the lower first premolar. Correct group assignment of individual teeth to their ancestral groups ranged between 80.0 and 92.8% for upper premolars and 60.0 and 75.7% for lower premolars. Discussion: Our findings provide evidence of significant size and shape variation in human premolars between the two ancestral groups. High classification rates based on shape analysis of upper premolars highlight potential application of geometric morphometrics in anthropological, bioarcheological and forensic contexts.Robin Yong, Sarbin Ranjitkar, Dimitra Lekkas, Demetrios Halazonetis, Alistair Evans, Alan Brook, Grant Townsen
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