Psychologists suggest that to cure cruelty

According to the results of the research carried out in Finland,

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   holding the brush like a pen reduces the harm done to the gums
   
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   most people are not aware of the proper way to brush their teeth
   
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   people feel great happiness when their teeth are well-cared for
   
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   people in general are quite careless about their teeth
   

Nearly five thousand years after a Chinese Empress discovered, quite by chance, how to unwind the fine thread of the cocoon of a silkworm, a Frenchman, experimenting with the crushed leaves of the mulberry tree on which the silkworm feeds found out how to produce a fine silk-like fiber which we now call artificial silk. His discovery stimulated other scientists to search for new fibers, and it was not long before several more were produced, but all of them had as their starting-point some natural organic material, such as cellulose, casein, etc. It is only fairly recently that man has succeeded in synthesizing new fibers from inorganic materials. Everyone has heard of nylon, and scarcely one of us can say he doesn't use something made from this product every day. But nylon was the first of an ever-lengthening list of new synthetic fibers. Now hardly a year passes without some new fiber making its appearance and some unfamiliar name finding its way into our everyday speech.

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