Hi,
My name is Richard and I am from New Zealand. I have several ideas on how to make this work.
I work as a software development team leader by day and have nifty tricks, currently I see at least 3 ways to get SMS working in Australia.
You will appreciate that OpenDental in the US uses CallFire which is a pay-per-use service, it will be no different once I get it working for Australian numbers - you will be looking at a fee of about 5c per SMS message.
Look forward to tackling this interesting challenge for you.
Regards,
Richard