Tooth brushing one they feel comfortable with, determine what is affordable for them and will be more likely to regularly brush with. Toothbrushes are offered with varying textures of bristles, and come in many different forms and sizes. Most dentists recommend using a toothbrush labelled "soft", since firmer bristled toothbrushes can damage tooth enamel and irritate gums as indicated by the American Dental Association. Toothbrushes are often made from synthetic fibers, although natural toothbrushes are also known in many parts of the world. Those with dentures may also brush their teeth with traditional tooth brushes, specially made denture brushes or denture cleaners.
Development of the nervous system intellectual disability. The mammalian central nervous system (CNS) is derived from the ectoderm—the outermost tissue layer—of the embryo. In the third week of human development the neuroectoderm appears and forms the neural plate along the dorsal side of the embryo. The neural plate is the source of the majority of neurons and glial cells of the CNS. A groove forms along the long axis of the neural plate and, by week four of development, the neural plate wraps in on itself to give rise to the neural tube, which is filled with cerebrospinal fluid (CSF). As the embryo develops, the