Can bisphosphonates reduce new bone production?

I might start by going to the top of this page to the search box and search bisphosphonates. It will give you a list with a very brief indicator of the topic that is being discussed.

Biphosphonates are not bone-builders. They are more for preventing bone loss.

Bisphosphonates slow bone resorption and do not aid in increasing bone density. So they might prevent a fracture but don’t build bone.

joeger, yes.
bisphosphonates don't clad your bone evenly. The medication is attracted to areas where bone units are working together to break down bone and build it up. The drug attaches to bone in a mottled way. It stops the bisphosphonates from breaking down bone by by cell death when osteocyte tries to resorb the bisphosphonate. Stopping the breakdown, stops the osteocytes from laying down new bone. You continue to remodel bone where there is no bisphosphonate attached. But the process is slowed down. So you add some bone and that increases bone mineral density but at a lower rate. You also gain density from the bone that is preserved under the bisphosphonate.
One caution is that as your bone becomes more avascular after delayed replacement it appears more dense on dexa.
Some of our drugs Prolia and Reclast stop the cells that breakdown bone and stimulate the cells that build bone. So they add bone on top of damaged bone.
If any of this is unclear, I'm happy to clarify.

@gently Prolia is a monoclonal antibody that prevents the formation of osteoclasts which break bone down. Reclast is a bisphosphonate that inactivates existing osteoclasts.