Know Your Porcelain Bond: A Guide to the New Resin Cements

I recently wrote a post about the new ceramics that have exploded onto the market.  I felt overwhelmed by the options and was confused about what I should incorporate into my practice.  If I was confused about porcelains, I had no idea what was waiting for me when I began to investigate resin cements.

If you’re doing a full coverage, all ceramic crown, then you can certainly use traditional cements (zinc phosphate and zinc polycarboxylate) without committing any major crime that would make your former prosthodontic professor wag an angry finger at you.


But if you do that, you’re missing out on an opportunity to take advantage of adhesive dentistry.  Many porcelains have a glassy matrix that can be etched.  If it can be etched, it can be bonded.

Let’s look again at my classification of porcelains:


Alumina and zirconia do not have any glass in them, so etching is challenging or impossible.  There are some products on the market that claim they can bond to zirconia, but the jury is still out.

Let’s look at my chart of adhesive cements and sort it all out.


Total-Etch: You prepare the tooth surface with phosphoric acid, then apply prime and bond.  The pros are it offers the best bond, especially to enamel.  The cons are that it can carry the highest rate of post-operative sensitivity.

Examples include: Variolink II, RelyX Veneer, Duo-Link

Self-Etch Primer: You prepare the tooth with a solution that has etch and prime in it.  Lower bond strengths but also less post-operative sensitivity.

Examples include: Multilink Automix, Panavia F 2.0

Self-Adhesive: You prepare the tooth with nothing.  Etch, prime and bond are all in the cement itself.  Lowest bond strengths but theoretically the best at reducing post-operative sensitivity.

Resin-Modified Glass Ionomer: You prepare the tooth with nothing, Etch, prime and bond are all in the cement itself.  The chemistry is different from self-adhesive cements and you usually have the bonus of fluoride release from the cement.

Examples include: FujiCEM, RelyX Luting Plus

So when do you use which cement?

If you’re placing a full coverage, all ceramic crown, you can use all of the above.  There may be a benefit to RMGI since it is the most tolerant of moisture and can handle subgingival preparations the best.

If you’re placing a porcelain inlay/onlay, I recommend a self-etch primer.  It offers the best bond for the least incidence of post-operative sensitivity.

If you’re placing a porcelain veneer, I recommend a total-etch bond.  Veneers benefit by having the strongest bond.  Also the incidence of post-operative sensitivity is low because veneer preps should rarely extend too far past the dentin-enamel junction.

The other significant factor to consider is whether the cement you are using is self-cure, light-cure, or dual-cure.  More opaque porcelain like zirconia or any porcelain thicker than 2 millimeters should not be cemented with light-cured products since the curing light can’t penetrate to the cement as effectively.

 

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11 Comments

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  4. Dr. Prosth says:

    I noticed that you said that RMGI is fine to use with all porcelain crowns. Are you worried about delayed expansion due to water imbibement of the cement (due to HEMA)? Gordon Christianson wrote an article on how he placed RMGI into a glass tube and put it into water. After some time the glass tube broke. I worry about both all porcelain crowns (not including alumina/zirconia substructure) fracturing or similarly roots cracking due to post cementation. BTW I like your website and I think you have very valid points about these ceramic and cement biomaterials.

    • Chris says:

      Hmm… that’s a very interesting point. I haven’t heard about this phenomenon but it makes sense. Personally I don’t use RMGI cements so I can’t say that I’ve seen this happen or not happen. Thanks for sharing!

  5. chris lee says:

    hi, i am in australia, trying to do zirconia maryland bridges for aesthetic reasons – ie to prevent the metal shining through.
    The only one i’ve done so far has debonded due to the cement (relyx unicem) not adhering to the Zirconia.
    any pointers?
    i have heard of this new technique which the labs use of spraying the Zirconia wings with normal feldspathic porcelain which can then be bonded to.
    what do the Yanks do??
    ta
    chris

    • Chris says:

      Hello Chris! I was fortunate to be invited to lecture in Australia last year. You have a beautiful country and I can’t wait to go back!
      There is an increasing number of cosmetic dentistry experts who are advocating all-ceramic Maryland bridges in the anterior. I agree that this can be a great way to go.
      I would strongly recommend you switch to lithium disilicate (e.max) instead of zirconia. Yes, zirconia is stronger, but e.max is plenty strong. More importantly, e.max has a glass matrix which means it can be etched and silanated. Using a self etch resin cement (like Multilink Automix) will give you a nice bond between the tooth and the restoration, especially in enamel.
      Bondindg to zirconia is controversial. There are studies that show sand-blasting and various chemical treatments can improve retention, but I’m still skeptical. And my guess is that whatever bond you can get to zirconia won’t be as strong as the bond to lithium disilicate.
      Cheers,
      Chris

  6. Anand Shah says:

    Any thought on using self-etching prime n bond with Variolink II. It is listed under total-etch. However, previous dentist in my office was using Variolink II with self-etching prime n bond and reported almost no post-op sensitivity. Does that reduce the bond strength considerably? What do you think?

    • Chris says:

      It can be done that way, but I don’t recommend it. Variolink II is meant for bonding veneers to enamel and dentin (but mostly enamel). It offers very strong bond strength which is needed for veneers, but only if it is used with a total-etch bonding system. Using a self-etch system will decrease the post-op sensitivity but it will decrease the bond strength as well. If he is using his protocol for full-coverage crowns then it probably doesn’t matter as much since there is greater surface area for retention and bonding than there would be for veneers.

  7. Mahmoud Ibrahim says:

    Hello
    Thanks for a great post. I’m about to venture into the world of emax and was interested in this point. I was weighing up whether to use FujiCem (RMGI) or Nexus (dual cure) and I would really like to know what you would recommend?
    Thanks for all the great posts.
    Regards
    Mahmoud Ibrahim

    • Chris says:

      Both are adhesive resin cements, meaning the etch/prime/bond is all contained in the cement. That should work fine for a full coverage restoration or an inlay. Personally, I like to use a self-etch resin such as Multilink Automix. There’s a much stronger bond but still a low chance of post-op sensitivity.

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