Enamel matrix derivative Enamel matrix derivative In dentistry, enamel matrix derivative (EMD) is an extract of porcine fetal tooth material used to biomimetically stimulate the soft and hard tissues surrounding teeth to regrow (in a process known as regeneration) following tissue destruction. There are three hard tissues that comprise human teeth: enamel, dentin and cementum. The majority of the tooth structure is formed from dentin, and the enamel serves as the superficial layer of the crown while the cementum serves to cover the root. In the mid-1990s, however, it was discovered that a very thin layer of enamel actually exists between the dentin
Sociology of human consciousness presumed evolutionary advantages of human reflectivity must be qualified or viewed as conditional. In sum, recent research, building on the work of George Herbert Mead, suggests that a sociological and social psychological perspective can be a point of departure with which to define and analyze certain forms of human consciousness, or more precisely, one class of consciousness phenomena, namely verbalized reflectivity: monitoring, discussing, judging and re-orienting and re-organizing self; representing and analyzing what characterizes the self, what self perceives, judges, could do, should do (or should not do)). The "hard problem" of consciousness can be approached fruitfully by beginning with