Can a Fiber Post Be Cemented with Conventional Glass Ionomer?
A colleague asked me:
“Can you cement a fiber post with glass ionomer too?”
I replied, “Of course you can. You can do whatever you like! 😂”
He then explained that, at their clinic, they had previously cemented fiber posts without resin cement, using only glass ionomer. He had now been offered a supply of fiber posts, if he needed them, to use with that same glass ionomer.
He asked, “Does having the post there make any difference? Wouldn’t it be better to use a cast post instead?”
I asked him, “What do you think a post is for?”
He said, “Better core retention and cervical reinforcement?”
I said, “Exactly, better core retention. But I don’t think a fiber post with conventional cement and frictional retention would perform adequately.”
But after reviewing the papers, I changed my mind
After that conversation, I decided to see what the scientific evidence says about cementing fiber posts with conventional glass ionomer.
I found four relevant papers and read their abstracts. The findings were contrary to my initial expectation.
In some laboratory studies, conventional glass ionomer provided adequate retention for fiber posts, and in some Push-out tests its results were comparable to or better than those of certain resin cements. However, the studies did not all produce the same results: in another study, post retention with the glass ionomer cement tested was reported to be considerably lower.
Another interesting finding was that hygroscopic expansion of glass ionomer, meaning an increase in volume caused by water absorption, may contribute to greater frictional retention of the post.
My initial view that a fiber post with conventional cement and frictional retention could not perform adequately was therefore too categorical. At least the laboratory findings do not support that judgment.
Of course, this does not establish the long-term clinical success of this approach or its superiority over resin cements.
My aim in this review was to check whether my own answer was correct, so I read only the abstracts rather than the full texts. If the question is only about fiber post retention within the canal, my initial answer was wrong. However, examining other potential problems with this approach is beyond the scope of this discussion, and this conclusion is not a clinical recommendation to use glass ionomer for cementing fiber posts.
References
The discussion above is based on the abstracts of the following papers, rather than a review of their full texts.
- Pereira et al., 2013 — Push-out bond strengths of different dental cements used to cement glass fiber posts.
https://pubmed.ncbi.nlm.nih.gov/23929375/ - Amaral et al., 2009 — An in vitro comparison of different cementation strategies on the pull-out strength of a glass fiber post.
https://pubmed.ncbi.nlm.nih.gov/19678450/The glass ionomer cement tested in this study was resin-modified.
- Effect of hygroscopic expansion on the push-out resistance of glass ionomer-based cements used for the luting of glass fiber posts.
https://pubmed.ncbi.nlm.nih.gov/16728245/ - Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements.
https://pubmed.ncbi.nlm.nih.gov/25004052/Full text, provided only for reader access:
https://pmc.ncbi.nlm.nih.gov/articles/PMC4245750/