 inorgan constitu human teeth bone examin x-rai emiss spectrographi x-rai emiss spectrographi appli studi element composit human teeth enamel dentin bone materi consist crush teeth enamel dentin powder separ eighteen teeth piec buccal cortic mandibular bone teeth fill materi contain nineteen element main calcium phosphoru sampl tooth materi cl fe zn sr bone contain ni time need semi-quantit analysi compar favour need method 