Nov 16, 2009 | EUROPE
Scientists in Germany develop hybrid composite for endodontics
LEIPZIG, Germany: Materials used in root canal procedures are not always compatible with each other or do not bond properly with the hard dental tissue. Root filling materials, for example, should not shrink as they harden and be visible in x-rays. On the other hand, materials used to rebuild the tooth should mimic the properties of the tooth itself. Researchers at the Fraunhofer Institute for Silicate Research ISC in Würzburg, Germany, now have said to have developed a new material that can be used for all components applied in root canal treatment.
The material which was developed in collaboration with researchers from VOCO, a German manufacturer of dental restorative materials, is based on organic-inorganic hybrid substances, so-called, ORMOCERs, that are combined with various nano- and microparticles. While standart material shrink by 2-4 per cent, ORMOCERs only shrink by 1.3 per cent as they harden. The can also be adapted to adhere to the different parts of the tooth, the researchers said.
ORMOCERS are already in use for optical functional coatings for glass and ceramic components or easy-to-clean coatings for metals and leather. According to ISC officials, the launch of a final product for dentistry will be in a few years.
ruction of four deciduous and one permanent teeth assessed for linear, surface, and volumetric tissue proportions. a: deciduous upper right central incisor (Ui1, labial view); b: deciduous lower right lateral incisor (Li2, labial view); c: deciduous lower right canine (Lc, labial view); d: deciduous lower right second molar (Lm2, oblique mesio-buccal view); e: permanent lower right first molar (LM1, oblique mesio-buccal view). The volumes of the virtually reconstructed teeth are rendered in transparency and each tooth component (enamel cup, dentine, and pulp chamber) is shown in different colours. Scale bar is 1mm. (DTI/Photo University of Bristol)Jan 8, 2010 | EUROPE
Ancient teeth shed new light on human evolution
BRISTOL, UK: The teeth of a 30,000-year-old child are shedding new light on the evolution of modern humans, thanks to research from the University of Bristol published this week in Proceedings of the National Academy of Sciences.
The teeth are part of the remarkably complete remains of a child excavated in 1998–9 in the Abrigo do Lagar Velho, Portugal. Classified as a modern human with Neanderthal ancestry, the child raises controversial questions about how extensively Neanderthals and modern human groups of African descent interbred when they came into contact in Europe.
The Lagar Velho skeleton. (DTI/Photo University of Bristol)
‘Early modern humans’, whose anatomy is basically similar to that of the human race today, emerged over 50,000 years ago and it has long been the common perception that little has changed in human biology since then. When considering the biology of late archaic humans such as the Neanderthals, it is thus common to compare them with living humans and largely ignore the biology of the early modern humans who were close in time to the Neanderthals.
With this in mind, researchers from France, the US and Portugal, reanalysed the dentition of the Lagar Velho child (all of its deciduous – milk – teeth and almost all of its permanent teeth) to see how they compared to the teeth of Neanderthals, later Pleistocene (12,000-year-old) humans and modern humans.
Employing a technique called micro-tomography, which uses x-rays to create cross-sections of 3D-objects, the researchers investigated the relative stages of formation of the developing teeth and the proportions of crown enamel, dentin and pulp in the teeth. They found that, for a given stage of development of the cheek teeth, the front teeth were relatively delayed in their degree of formation. Moreover, the front teeth had a greater volume of dentin and pulp but proportionally less enamel than the teeth of recent humans. The teeth of the Lagar Velho child thus fit the pattern evident in the preceding Neanderthals, and contrast with the teeth of later Pleistocene (12,000-year-old) humans and living modern humans.
“This new analysis of the Lagar Velho child joins a growing body of information from other early modern human fossils found across Europe (in Mladeč, Czech Republic; Peştera cu Oase and Peştera Muierii, Romania; and Les Rois, France) that shows these ‘early modern humans’ were ‘modern’ without being ‘fully modern’. Human anatomical evolution continued after they lived 30,000 to 40,000 years ago,” co-author Prof. João Zilhão, University of Bristol, commented.
(Edited by Claudia Salwiczek, DTI) Link.....