By: Dr. David Rice
Dental cement – with all our indirect material options today-understanding the decision tree from cast gold, to PFM, to Glass Ceramics, Zirconia, and everything in between is key.
Saying that, yes we use dental cement in other spaces too-temporary restorative, endodontic sealers, and orthodontics bracket attachment to name a few
For this article, we will restrict our conversation to definitive, restorative cement solutions.
If you’d like to learn more about any of the others or you’d like to ask questions on cases you have-please feel free to message me at firstname.lastname@example.org or DM me @igniteDDS on Instagram.
I am always happy to share more.
Choosing Which Dental Cement Is Best
Step 1. Have the Patient’s Ideal End in Mind
Begin with the patient’s ideal end in mind:
- How beautiful does their indirect restoration need to be?
- How strong does it need to be?
- Do I have design freedom-aka-veneer versus inlay versus onlay versus crown?
Patients need to fully understand that a 10/10 in beauty will inherently compromise strength to some degree. Meaning the prettiest materials we have in dentistry, although stronger than we historically had, are still weaker than their less-than-pretty counterparts. As you’ll see later, this is important to note when it comes to dental cement selection.
Let’s play that out. Feldspathic, Leucite, some Lithium Silicates, and a short list of Zirconia are pretty-and at times- can be too weak to lute. Meaning, when we have a patient who wants to be on the cover of a magazine-wants a 10/10 and we choose one of the weaker ceramics, our dental cement needs to live in the bonding family of dental cements.
*Please re-read that list.
Not all Lithium Silicates and Zirconia are as strong as you think. It does not make those choices poor choices. It does make it necessary for us to think about our material thickness which in turn can change our prep design-aka-our next category as well as-how strong and how much control we have with our design freedom.
This is especially important in the anterior segment where patients most often want maximum beauty. Again, not a bad thing, just a thing we need to step back-contemplate-and share what that means to them in our material selection and process.
Another key. If your practice is like mine, you have delicate patients who’ve had curious dentistry that somehow, someway just seems to last. Win! You’ve also had patients who look at a superhuman restoration a mile away and somehow break it.
Thankfully for us, most are somewhere in the middle and most of the time we have signs and symptoms we can learn of pre-treatment-like excess wear-abfraction-recession-sensitivity-chips and breaks etc-that tip us off.
As we stated in how beautiful, inherently weak materials need to be bonded. What I’ll add here is inherently strong materials like Lithium Disilicate (I still prefer to bond this FYI), many Zirconia, PFM, and Cast Gold are very lutable.
Our problem lies in the patients who want 10/10 beauty and need 10/10 strength. That leads us to category three.
The more conservative we are in our preparation design-aka-the less space and more non-retentive we are-the more we need to bond. All veneers-inlays and most onlays (ceramic) need to be cemented in an adhesive manner.
The more aggressive our preparation-3/4 to full crowns with plenty of clearance-remembering how beautiful and how strong play a role-the more you and I can lute.
Step 2. Luting vs. Bonding
I need to think about my dental cement options for luting vs bonding.
We’re going to keep this one simple. Today’s most popular luting agent is the resin-modified glass ionomer (RMGI). It’s fast-effective-reliable-and most major manufacturers do a solid job delivering one.
For posterity’s sake-you can also choose a Glass Ionomer Cement and I’m sure a few of you reading this still have that drawer with some old-school Zinc Phoshate.
What is very important to note is luting requires two factors. You must have inherent restorative material strength and you must have inherent retention form in your preparation design. If you unplug either one of those you will see premature failure in many patients.
When you’re working with weaker materials and/or ultra-conservative preparations and you need maximum beauty-think bonding and think resin dental cements.
We’re going to keep it high-level today and break this thought process into two buckets.
Bucket 1: You have minimal to no enamel.
When this is your clinical situation and you want/need to bond-you have options. You can work with a self-adhesive resin cement or you can work with a resin cement that requires an external etchant. For me-that choice is driven by my ability to isolate and my patient’s ability to sit still for a few extra minutes.
*Like RMGI’s above-we have plenty of excellent options in dentistry today.
Bucket 2: You have plenty of available enamel.
When this is your clinical scenario-total adhesion is your success path-aka-working with a system that allows for an external etchant + your resin cement wins. There is incredible data to support this modality. Again-isolation is key and again great news. Most of the top manufacturers have an excellent option for us.
Step 3. Light vs Dual Cure
When bonding-do I light vs dual cure?
Last and not least-when I know I’m going to bond with resin cement and the total adhesive process-I need to think about when to dual cure and when to light cure only. The high view is the simple view. When I can predictably get my light source to the tooth-dental cement-restoration interface-I can choose either.
A few factors play into this:
- First: How thick is my material? If I’m > 1.5 mm- I’m dual curing and not taking a chance.
- Second: How translucent is my material? If I’m using a material that has opacity in any way-I’m dual curing and not taking the chance.
- Third: How much time do I need? This is my veneer insertion example. I know I’ll be using at least a relatively translucent material if not very translucent. I know I’m typically 0.6mm or less. I know I’d like as much time as I can have to make sure I have ideal seating and orientation-therefore-whenever possible I am light curing only.
Which Dental Cement Should You Use?
In conclusion-dental cements can be confusing.
We have multiple reasons and multiple categories within categories that factor in.
Beginning with the end in mind and working backward will help you choose the best option for your patient and the case at hand.
Photo by Andrea Piacquadio