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May-June 2016 | No. 3, Vol. 6 Published in Dubai www.dental-tribune.me Poor dental health may predict reduced ability to leave one’s house ByDTI SENDAI, Japan: Researchers in Japan have investigated the association between poor dental health and be- ing housebound in the elderly, and found that having fewer teeth and no dentures were associated with future risk of being homebound, especially in people aged 65–74. The findings may have important impli- cations for interventions that pro- mote dental health and denture use topreventolderpeoplefrombecom- ingconfinedtotheirhomes. The longitudinal cohort study used data of 2,035 men and 2,355 women aged 65 and over who responded to two postal surveys conducted in 2006 and 2010 and were not home- bound, defined as leaving their home less than once weekly, at base- line.Afterthefour-yearstudyperiod, 324 (7.4 per cent) of the respondents werehousebound. With regard to dental status, the researchers found that, overall, par- ticipantswithfewer teethweretwice as likely to be confined to the house than those with more teeth were. Al- most 10 per cent of the homebound respondentshadfewerthan20teeth and no dentures, about 9 per cent had fewer than 20 teeth and den- tures, and about 4 per cent had 20 or moreteeth. However, such a significant as- sociation between being home- boundanddentalhealthwasnot observed in participants aged 75 andover. According to the researchers, several possible pathways may link dental health and being bound to one’s home. For ex- ample, dental health, including loss of teeth, affects food choice and nu- tritional intake, conversation, and facial attractiveness. Therefore, poor dental health could negatively influ- ence social activities, leading indi- viduals to isolate themselves from others. Being housebound in itself is abarriertoaccesstodentalcare. The researchers concluded that fu- ture intervention studies focused on improving dental health in order to prevent older persons in the Japa- nese population being homebound are required to verify the findings. They suggested that improving the rateofdentureuseamongolderpeo- ple with fewer teeth could reduce their risk of becoming housebound inthefuture. The study, titled “Does poor dental health predict becoming home- bound among older Japanese?”, was published online in 30 April in the BMCOralHealthjournal. Astudyhasfoundthatpoordentalhealthmaybelinkedtofutureriskofbeinghomebound. (Photograph:pixabay/stevepb) Testing toothpastes, toothbrushes Improving dental hygiene products through virtual brushing ByDTUS Designing toothpastes and tooth- brushesisatime-consumingprocess involvingtheproductionandtesting of numerous samples. Using a new type of simulation, various param- eters such as bristle shape and abra- sive particle size can be modified with just a click. This enables manu- facturers to improve the quality of new dental care products and bring themtomarketmorequickly. When we wake up in the morning, there is a fur-like coating on our teeth: this is a biological film that forms overnight. Over time, this can lead to the development of caries — which is why it is critical that we re- movethis“rug”usingatoothbrush. There is a large selection of dental hygiene products on the market, in- cluding brushes whose bristles are rounded, pointed, hard, and soft. There are also brushes with bristles of varying lengths. Until now, to de- termine which ones clean the most thoroughlywhiledoingaslittledam- age to the tooth enamel as possible, manufacturers have had to conduct experiments. This was also the case when selecting the right abrasive particlestobeusedintoothpastes. Various toothpaste formulations had to be mixed and then tested on artificial tooth enamel models — a laborious task. Another drawback to thisapproachisthatthebrush,paste andenamelcanbeanalyzedonlyasa complete system, which means that manufacturers have a difficult time determining which effects observed in these experiments are derived from which of the various param- eters. Helphasarrivedintheformofanew type of simulation developed by re- searchers at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany. “With our pro- cedure, manufacturers of dental hy- giene products can determine the cleaning effectiveness of each indi- vidual parameter in a fast, economi- cal and reliable manner,” says IWM scientist Dr. Christian Nutto. “Unlike in real-world experiments, the indi- vidual parameters in the simulation can be easily modified — be it the size, shape and quantity of abrasive particlesinatoothpaste,orthemate- rialfromwhichtheyaremade,orthe shapeandelasticityofthebristles.” Simulatedtoothbrushing Researchers can increase the scope of the experiments far beyond what is possible in real-world testing, and that makes a noticeable difference in the quality of the products. What effects do the shape and stiffness of the bristles have when brush- ing? How do the different abrasives or toothpaste viscosity affect the enamel, and how do they affect their intended target, the biofilm on the teeth? Simulation testing can deliver reliable answers to questions such as these, and it does so long before the manufacturer ever mixes the tooth- paste. Nutto relies on SimPARTIX® simu- lation software developed at the IWM, which uses the Smoothed Particle Hydrodynamics (SPH) parti- cle simulation method. “We specify characteristics for the abrasive par- ticles such as density, shape and fill factor,” he says. Even parameters for the tooth enamel are included. The virtual toothbrush bristle is then rubbed over the tooth enamel, with the simulation providing data on how the scrubbing particles interact with the elastic bristle. It also calcu- lates cleaning effectiveness, as well as the aggressiveness of the abra- sives against the tooth enamel. Here, the team from the Powder Technol- ogy, Fluid Dynamics group can vary the speed at which the bristles pass across the enamel as well as their pressingforce.TheSimPARTIXteam, together with the Fraunhofer Insti- tute for Algorithms and Scientific Computing SCAI, designed an addi- tional software tool to integrate the particle simulation into standard- izedsimulationprograms. Butdothefindingscorrespondtore- ality? The comparative experiments Simulation of pressure distribution in suspensions of varying viscosities with spherical abrasive particles as a toothbrush bristle rubs against tooth enamel: The more viscous toothpaste suspension leads to greater abrasion on enamel. Fig. 1: Lower viscosity (1 mPas). Fig. 2: Higher viscosity (20 mPas). Left-side im- agesshowpressuredistributioninthesuspension(adeeperredindicateshigh- er pressure). Right-side images show stress input against the tooth enamel by abrasive particles (a deeper red indicates greater abrasion). Images/Provided byFraunhoferIWM Simulation of interaction between a tooth- brush bristle and a suspension with spherical abrasiveparticles. ÿPage2