A Tall Order: Navigating Restorative Materials and Dental Cement Selection

Regular or Decaf. It used to be so easy. For those adventurous types, there was always the option for cream and sugar, too. Today? Dozens of options to choose from – Espresso, Macchiato, Cappucino, Americano – tall, short, light, dark, caf, decaf, fat, non-fat. You get the picture. Has this improved the coffee drinking experience? Judging by the lines at the local houses-of-Joe I’d say people are enjoying the options; however, that doesn’t necessarily mean it’s an easier process for ordering that daily waker upper, and I’d argue the odds are lower that you’ll get exactly what you want without the occasional mistake.

This has certain parallels to selecting and working with crown and bridge materials, as new offerings – and the results you can get with them – can be enjoyable, yet processing the changing materials rules can be frustrating, as well.

I think the IQ on material and dental cement selection is falling because the number of choices has exploded in recent years and isn’t stopping. My Dad is also a practicing dentist and he has talked about what it was like 15 years ago when your choice was either PFM, gold or maybe a pressable. Your cement was an RMGI or full resin. That’s it. The actual materials had their downsides, but there wasn’t much mystery around the technique – you knew how to work with them.

And how about now? PFM, gold, pressable, porcelain, glass ceramic, zirconia, hybrid? Silanated, etched, aluminum oxide blasted? RMGI, self-adhesive, universal, resin, bonded resin?

From a materials perspective, we have a lot better options than we’ve ever had before, but with those options comes a lot more complexity. When that happens your chances of making a mistake go up. And, I will admit, it’s difficult for someone who WANTS to do it to stay fresh on products and their rules. What about those who aren’t materials geeks? It can be a struggle.

Yes, everything isn’t as simple as black or cream & sugar, regular or decaf, but dentists do seem to enjoy the options and they are getting more comfortable with the parameters required for their favorite materials.

In the current state of how I’m practicing, I would say most of my molars and 2nd bicuspids are getting full-contour zirconia restorations. I like full-contour zirconia. I like the idea of it being able to be thin and not an aggressive prep. In the posterior, you’re fighting the battle between adequate clearance and wall height, and I’d rather have more wall height. Zirconia’s strength is appreciated. If possible, I would prefer to lute these with an RMGI cement than bond them in with a cement, provided I have adequate wall height to my prep. If I feel pretty good about the amount of tooth structure, I would rather lute than bond. To me, bonding is more technique sensitive and a little messier.

However, on the social eight, I tend to use a lithium disilicate and bonded resin cement.

There is a difference in the inherent strength of the restorative materials we use. For example, we know the strength difference between zirconia and glass ceramic restorations. As the material strength decreases, the need to choose a stronger, bonded cement increases. This is why so many dentists choose to use a bonded resin cement with lithium disilicate – to add strength to the material. On the other hand, zirconia is a very strong material and doesn’t require the cement to provide the strength. In these cases you can opt for a less technique-sensitive luting of the restoration with an RMGI or self-adhesive resin cement.

So, how can you wade through the materials options and find the best material/dental cement pairing? Start with some basic questions:

1. Any relevant medical history for the patient?
2. What are the esthetic/strength requirements of the restoration based on its location in the mouth?

As you decide on the restorative material:

1. Will you have a retentive prep?
   a) At least 3-4 mm of wall height
   b) Parallel walls
2. If non-retentive, can you keep a dry field/isolation?

Your answers to these questions, as well as any unique factors in the clinical situation, will determine what direction you go for material and cement pairing. Keep in mind that proper selection of these materials needs to then be followed by proper use of said materials. As you explore options searching for your preferred approach, never make assumptions that one material will act like another. Always read the instructions for use carefully before trying any new product.

And if you decide to try a new coffee drink at your favorite local stop, it can be very enjoyable, but don’t be surprised if it’s more complex than you ever imagined.