If your income is below a certain threshold, you may be eligible to get a health care concession card from the Centrelink. You can then take this concession card to the nearest government dental clinic. They will provide you the required dental treatment there or they may provide a $600 emergency voucher for toothache etc or $1500 general voucher for other dental works.

Please note there may be a waiting time of 2 months to 8 months for $1500 voucher.