A Hemispherical Contact Model for Simplifying 3D Occlusal Surfaces

Statement of problem Currently, dental articulators can recreate mandibular movements and occlusal contacts. However, whether virtual articulators can also provide information about occluding dental surfaces, functional movements, and the mandibular condyles is unclear. Purpose The purpose of this in vitro study was to evaluate the occluding surfaces on dental casts obtained from a patient and approximate them to a hemispherical contact model. Both models were tested by digitizing the Dentatus ARL dental articulator. Material and methods A combination of photogrammetry and structure from motion methods were used to scan a Dentatus ARL articulator and representative dental casts. Using computer-aided engineering and finite element analysis, contact points and action vectors to the forces on occluding surfaces and condyles were obtained for cast and hemispherical models. This experiment was performed using centric occlusion and 3 different condylar inclinations. The Kruskal-Wallis 1-way analysis of variance on ranks test was used to allow all pairwise comparisons between condylar inclination and mechanical action vector values in each location (α=.05). Results Action vectors from the cast model and each location of the hemispherical model were calculated to show the mechanical consequences and the similarity among models. Overall, no significant differences were observed for action vectors (A20 versus A40 versus A60) at each location (dental cast/hemisphere, right condylar, and left condylar) in the analysis of dental casts and the hemisphere model (.382≤P≤.999). Conclusions This study provided graphical information that may assist the dental professional in determining which occlusal contacts should be modified to attain condylar and balanced centric occlusion

Digitalización y visualización 3D de cerámica arqueológica

[ES] El sistema de documentación y registro del material arqueológico ha experimentado un notable desarrollo gracias a la aplicación de nuevas tecnologías. Estas innovaciones han resultado bastante útiles en el campo de la documentación, análisis y visualización del material arqueológico. En este artículo se expone una metodología de trabajo para la realización de modelos 3D de cerámica arqueológica. Esta metodología se encuadra dentro del proyecto CATA (Cerámica Arqueológica a Torno de Andalucía), cuyo principal objetivo es la realización de una colección de referencia de formas cerámicas completas documentadas en intervenciones arqueológicas de Andalucía. Dicha colección de referencia contiene información concerniente no sólo al proceso de fabricación, la descripción del tratamiento de superficie, o el contexto de hallazgo de la pieza, sino que también se pueden visualizar modelos 3D, permitiendo un mejor conocimiento de la pieza.[EN] The documentation system of the archaeological material has development in the last years thanks to the application of new technologies. These innovations have been quite useful in the field of the documentation, analysis and visualization of the archaeological artefacts.In this article a methodology for the achievement of 3D model of archaeological pottery is exposed. This methodology fits within the CATA project (Archaeological Wheel Pottery of Andalusia in its acronyms in Spanish). The main objective of the project is the implementation of a database which is accessible by Internet, containing assorted information about pottery vessels and fragments found in Andalusia in different periods. This reference collection contains information concerning not only the manufacture process, the description of the surface treatment, or the context of finding of the ceramics, but also 3D models that allows a better knowledge of the vessel.El desarrollo de todo este trabajo ha sido posible gracias a la concesión por parte de la Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía del Proyecto de Excelencia HUM 890 Corpus Virtual de Cerámica Arqueológica.Martínez Carrillo, A.; Ruiz Rodríguez, A.; Rubio Paramio, MÁ. (2010). Digitalización y visualización 3D de cerámica arqueológica. Virtual Archaeology Review. 1(2):133-136. https://doi.org/10.4995/var.2010.4715OJS13313612BERMÚDEZ RODRÍGUEZ, Francisco et al. (2000): Intervención virtual en el patrimonio arquitectónico. Las termas romanas de Sant Boi de Llobregat (Barcelona). Actas del XII Congreso INGEGRAF. Valladolid. Junio 2000.IMMLER, Christian (1997): El gran libro de 3D Studio Max. Marcombo. Barcelona.KARASIK, A.; SMILANSKY, U. (2006): Computation of the Capacity of Pottery Vessels Based on Drawn Profiles, Excavations at Tel Beth Shean 1989-1996, vol. I, Mazar A. (ed.), Jerusalem (Israel).LAUDON, K.C.; LAUDON, J.P. (1996): Management Information Systems, Organization and Technology (B.4) Prentice-Hall, Inc., New Jersey (United States).LOUISE, M.S. , DUNBAR, P.B. (1995): Accurately Estimation Vessel Volume from Profile Illustrations, American Atiquity 60/2, pp. 319-334. http://dx.doi.org/10.2307/282143MAGALLÓN LACARTA, J.A. (1999): Generación por ordenador de modelos tridimensionales correspondientes a distintas etapas de la catedral de la Seo. Actas del XI Congreso INGEGRAF. Logroño-Pamplona.MILLER, Phillip et al. (1996-1997): Inside 3D Studio Max.. New Riders Publishing, cop. Indianapolis.RUBIO PARAMIO, M.A. et al. (2002): "Baños Árabes del Palacio de Villardompardo (Jaén). Estudio gráfico-cronológico y diseño de una herramienta multimedia para su promoción". XII Congreso INGEGRAF. Santander

A New Method for Quantifying the Asymmetry of Biological Elements by Means of a Photogrammetric Technique Using a Parametric Computer-Aided Design System

In the area of zoology, it is of great interest to determine the degree of asymmetry existing in the different animal structures in order to establish it as a variable (biomarker). In this study, a new methodology is proposed for obtaining this variable ‘Asymmetry Index’. Forty-eight Iberian red deer antlers (Cervus elaphus hispanicus) from hunting reserves in the province of Jaen (Spain) have been used. The degree of asymmetry of their antlers between homologous points considered in the two right and left sides of each antler was obtained. The methodology is applied within a parametric Computer-Aided Design system from the photogrammetric restitution of the antler from two photographs. The procedure compares the degree of asymmetry in which the points of each of the right and left sides of the antler are found by means of lengths and angles with respect to an established reference plane based on the geometry of the specimen’s skull. As a result of the study, it has been observed that the Asymmetry Index obtained is lower in those specimens that have a high score in their hunting valuation, so it is considered that this factor can be taken into account as an objective and quantifiable indicator (biomarker)