Official Luthiers Forum!

i think what people are referring to regarding shell dust being dangerous is the silica content, which gets in the lungs, never breaks down(it is glass), and can lead to silicosis and lung cancer. more for something like a quarry worker or concrete cutter to worry about i'd guess; cutting a bit of shell now and then probably isn't deadly
http://www.cbs.state.or.us/osha/pdf/pubs/3301.pdf

In case you didn't notice, Stewmac has (acrylic) pearloid dots and other shapes. The acrylic faux pearl looks pretty good. It's possible to buy the stuff in sheet form too, but I have no idea of availability in Taiwan.

Celluloid fake pearl and abalone has been used for decades. It is possible to buy small sheets of this for pickguards or whatever. (check electric guitar supply places) If you wanted to be a cheapskate, you could punch some dots out of guitar picks, though they'd be thin and at risk for sanding through.

Filling a recess with resin/putty/whatever is never going to look as neat as inlaying a prepared piece. It can work ok for something easy, like a dot, as long as the wood is well sealed.

If you wanted to be a super cheapskate you could buy a sheet of shell looking adhesive stickers. Just trim and stick before finish. Lol