Again, thanks for questioning the explanation I received.
Not easy, but I did find something that explains it a bit. Here's the reference:
Anitua, E., et al, "PRGF exerts a cytoprotective role in zoledronic acid-treated oral cells," Clinical Oral Investigations, April 2016 (abstract)First, that "special bone" is called alveolar bone. It is the bone with a socket that the tooth sticks to.
Here is the smoking gun paragraph:
"The in vitro results presented herein show that ZA exerts a dose-dependent cytotoxic effect on proliferation and survival of human primary gingival fibroblasts and alveolar osteoblasts (Figs. 1 and 3). The ability of ZA to inhibit cell growth and to promote cell death has already been described."The graph shows the degree of apoptosis (cell death). It shows increasing bone death over the course of nine levels of exposure, meaning it is dose dependent as stated above. So the comment that the special bones die on the first treatment does not appear accurate. That does not mean we're in the clear. Read on.
"BPs are stored in the bone and slowly released to the immediate microenvironment thus affecting local gingival fibroblasts [1,23,25], which might involve that bone exposure to ZA concentrations is several-fold higher than the ones receiving gingival fibroblasts."So, the Zometa is absorbed into the bone and slowly released. One question leads to another. How long does it take to dissipate?
I did a quick search. One source said that the bone half-life of Zometa is 360 days. Let's call it a year. Another source said ten years. I doubt anyone sat around for ten years. So it may be an questionable extrapolation.
The way I read it is: Zometa inhibits regeneration of alveolar bone in a dose dependent way. It can take between one and ten years for the affect to decrease 50%. Or two to twenty years for the affect to decrease 75%.
My take-away: If I take Zometa monthly for a year, my risk for ONJ is not going away anytime soon. And that is OK. I'd rather live longer and deal with the inconvenience of taking good care of my teeth and gums and maybe dealing with occasional ONJ.
Personally, I had just one dose of each Zometa and Aredia. The result was acute phase reaction both times and a trip to ER. Fortunately my bone lesions partially healed after the autologous stem cell transplant. Maybe a new treatment will be available by the time of relapse for me.
If you have the time, read the full article. Maybe you'll have a different interpretation. I'd be glad to be wrong and find that the ONJ risk is much less.
