Some time an estimated 7,500 to 9,000 years ago, early man is suspected of using flint tips to drill into the enamel of teeth.  Several skulls were found in Pakistan  which appear to have molars drilled with flints, as reported in Nature in 2006.  More recently though, a 6,500 year old tooth has been found in Slovenia  with what is now regarded as the earliest (to date) dental filling material: beeswax.  The early Neolithic inhabitants where the tooth was found engaged in farming, and used bees and wax.  Many times primitive remedies find modern uses.  Modern dentists use beeswax too, but not as a filling material!