implants0112

I 49implants1_2012 Using a combination of guillotine-based experi- ments and cutting-edge computer modelling, re- searchersattheUniversityofBristolhaveexplored the most efficient ways for teeth to cut food.Their resultsdemonstratehowpreciselytheshapeofan animal’s teeth is optimised to suit the type of food it eats.There is massive variety in tooth shapes in the natural world, from long, serrated teeth in Tyrannosaurusrextotriangularteethinsharksand ourowncomplexmolars.Teethcanenableanimals to crush, chop, grind or even cut food into pieces small enough to swallow. Such cutting instru- ments, however, are not restricted to toothed ani- mals.Bird beaks,insect mouth parts and even the roughened tongue of snails can also be used to breakdownfood.Nevertheless,howteethareable to cut and break down food has not been exten- sively examined.Now,two researchers at the Uni- versity of Bristol’s School of Earth Sci- ences have investigated this prob- lem. In their study, research fellow Dr Philip Anderson and lecturer Dr Emily Rayfield used a unique double-bladed guillotine and measured the force needed by differenttoothshapestocompress food materials. Finite-element analysis, a computational engi- neering technique, was then used to mimic these experiments and meas- ure different variables, such as the total en- ergyrequired.Theresearchersfoundthatdifferent shaped bladed teeth are optimised for different types of food. “Theactualhardnessortoughnessofthefooditem has a strong effect on what type of tooth shape is most efficient for cutting it,” Anderson said. “We looked specifically at V-shaped bladed edges, which are similar to tooth shapes found in some sharks and the cheek teeth of many carnivorous mammals, and found that the angle of the V could be optimised for different foods.”According toAn- derson, this sort of analysis is only possible with a computermodel,whichtheresearcherscreatedto mimicthephysicalexperiments.Withthevalidated model,they were able to alter aspects of the tooth shape until they found a specific shape that used the least energy. “These re- sults might seem rather obvious,”said Rayfield, “because we know tooth shape is adapted to diet. But we were surprised at the precise- ness and predictability of the fit of tooth shape to dietary item.” The researchers hope this new integrated methodology will create a new framework for exploring the evolutionary history of dentalshapeandhowitrelatestodiet.Theirstudy, “Virtual experiments, physical validation: Dental morphology at the intersection of experiment and theory”, was published ahead of print on 7 March in the Journal of the Royal Society Interface. Reference:DTI Most efficient way explored Researchers investigate efficiency of bladed tooth shape Researchers from Linköping University in Sweden havesuccessfullytestedanewdrugcoatingonhu- mansthatallowstitaniumimplantstoadheretothe bone better and more rapidly. The findings could benefit patients with difficulty chewing following dental treatment. Millions of people have bad teeth replaced with dentalimplants,whichareembeddedintothejaw- bone and provide retention for artificial teeth.After the procedure, many patients are unable to chew food.Usingthecurrenttechnology,itmaytakefour to six months before the bone surrounding the im- plant has healed and is strong enough for the pa- tient to begin to benefit from surgery. Thenewcoatingconsistsofananometre-thinlayer of protein that adheres to the metal surface. At- tachedtotheproteinisadrugbelongingtotheclass of bisphosphonates, usually used to treat osteo- porosis. Now,forthefirsttime,thismethodhasbeentested onhumans.Thestudyinvolved16patients.Eachof them received two implants—one ordinary im- plant and a similar surface-treated implant as de- scribed above. Neither the patient nor the dental surgeon knew which was which.After six months, it was noted that for 15 of the 16 patients the sur- face-treatedscrewwasmarkedlymuchbetteres- tablished.Already after two months,X-ray images showedpositivechangesinthetissuesurrounding the surface-treated implants.According to the re- searchers,no complications occurred. “It is the first time ever anyone has succeeded in reinforcing the bone around an implant with lo- calised medication,” said study leader Per Aspen- berg, Professor of Orthopaedics, who devised the method of using bisphosphonates in this way.The study was published online in the Bone journal. Reference:DTI Study shows success New coating accelerates fixation of dental implants