I think there is confusion between Prolia - a 6 monthly injection and Zolendronic acid delivered by iv. Personally I wouldn’t accept the latter as is a bisphosphonate.
With Prolia it exits the body totally after 6 months enabling dental work to be done safely between injections.Bisphosphonates stay in the body continuously and many dentists are reluctant to help you if you need an extraction or root canal because of the risk of osteonecrosis of the jaw.
Have a look at the Australian Osteoporosis website and ask plenty of questions of medical staff.I urge caution and talk to your oncologist maybe even a specialist in the field of osteoporosis not your GP.
Re costs of Prolia .If you’ve been diagnosed with osteoporosis and are either over 70 or had had an osteoporotic fracture ( not sure if that includes toes) the cost is around $38, if not it is around $275.Prolia also is acknowledged as reducing bc recurrence risk.
Regardless of the choice you make have a thorough dental check before starting either and ensure all dental work is up to date.