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3 Tips for Selecting the Right Dental Cement Plus, a Bonus Checklist for Bonding Zirconia

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Today’s cement manufacturers have access to more and better resources than ever before. Plus, the continuous evolution of restorative materials has created a need for different cements, which can result in a lot of confusion about what cement is best.

While some dentists are loyal to one cement and use it for almost every procedure, there is an argument to be made for having multiple on hand. Sometimes cement types may share a few similar benefits, but that doesn’t mean both are the same or perfect for every indication. Not all cases are the same, so dentists have to ask themselves; “Is my go-to cement really best for this indication, or is there a better option in this case?”

There’s no one-size-fits-all solution for cementation, so familiarizing yourself with multiple cements could make a world of clinical difference in your practice. Here are a few tips to help you implement a simple cement selection system…

Introduction

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TIP #1: Know your options

Dentists must carefully consider what type of cement is most suitable for each individual case depending on the material being bonded. Assuming you already use a dedicated veneer cement, three additional types of cements to consider having in your arsenal are adhesive and self-adhesive resin cements, and a resin-modified glass ionomer cement.

In the past, adhesive resin cements were significantly more technique-sensitive than self-adhesive resin cements, but today’s materials have narrowed this gap. These advancements allow dentists to choose a cement based on the indication and desired bond strength.

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Adhesive Resin Cements Adhesive resin cements provide the highest strength of all three, in part due to the multiple component system that requires a separate adhesive.

Use when: Retention is a concern and the highest bond strength possible is needed: CAD/CAM glass ceramic restorations/veneers Inlays/onlays, short crown preparations Bonding to small surface areas including Maryland and inlay bridges Moisture control is achievable Excellent esthetics is an end goal

Self-Adhesive Resin Cements

Use when: Cementing zirconia Ease of use is key, but good performance and bond strength are still needed Cementing fiber posts

Self-adhesive resin cements can save a lot of time by eliminating the need for additional steps, while still providing high strength.

Resin-Modified Glass Ionomer

Use when: Cementing porcelain-fused-to-metal (PFM) or metal Prep retention is adequate When Fluoride release is needed: Pediatric crown placement Orthodontic bands Geriatrics crown placement Cementing implant abutments It’s difficult to control moisture during placement

The strength of RMGI cements is typically lower than resin cements, but the fluoride release has made these cements a practitioner favorite for use with caries-prone patients.

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TIP #2: Consider the situation at hand

There are many components that factor into perfect cement selection, including the patient’s habits, health, status of the gingival tissue and moisture control. While there are a lot of things to think about, two factors typically stand out as the most prominent for consideration:

1. Restorative material strength2. Prep retention capabilities

As restorative material strength and prep retention increase, required cement strength decreases. For example, if you have a prep with good retention and are using a PFM crown, you would be in good shape to use an RMGI cement. However, if your prep is less retentive and you’re using a glass ceramic crown, you may need to use an adhesive resin cement to ensure the strength of the restoration.

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TIP #3: Go beyond bond strength

We make decisions in our lives based on MANY different inputs. For instance, in choosing a car, we make the assumption that it’s going to get us from point A to point B – those are table stakes! Once we get past the obvious need, we begin thinking about the details. Is it made by a reliable manufacturer? What is the layout of the interior, and is it designed well so every feature is easy to use? Does it come with heated seats and built-in Apple Play™? Similarly, there are multiple inputs to consider when choosing a dental cement. (Reminder: There is no one cement that can do it all!) Bond strength is the laser-focus for many dentists regarding cements, because failure is associated with loss of the restoration – again, this is table stakes! However, there are several other factors to consider when deciding on what cement becomes your go-to.

Besides bond strength, what should you be looking for and where do you start?

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Consider how long a manufacturer has been in the market. Do they produce other trusted products? What is their level of understanding of clinical dentistry and will you be supported?

1. Buy the product and the company

This is where looking at the science is critical. How well researched is the cement you’re using? Does it have a strong, and ideally, long-term clinical history?

2. Reliability and long-term stability

Simple techniques usually rule the day in dentistry. Complexity increases the chance of introducing error, contaminants, and moisture – all things that can affect the overall outcome. Adhesive resin cements can offer the highest mechanical properties available, but if the technique is not followed correctly, you could end up with post-operative sensitivity or debonding. Conversely, a conventional RMGI cement is very simple to use but has mechanical and esthetic limitations. What technique is required for each cement? When does it make sense to forego a complicated technique for something more straightforward?

3. Simplicity

Based on the clinical situation, will the cement you choose need to have a certain level of moisture tolerance? What about flexural and compressive strengths? Are these fully understood across your cement portfolio? What kind of retentive quality does your prep have, and how strong is your chosen restorative material? Reviewing current literature can save you time and effort vs. experimenting in the chair.

4. Mechanical Properties and Moisture Tolerance

What are the esthetic requirements of your restoration? Esthetic restorative materials are, generally, weaker than traditional crown and bridge materials. For instance, glass ceramics provide an esthetic appeal that’s not achievable with stronger materials like PFM or some zirconia. However, you can quickly negate the effects of a beautiful restoration with a cement that shows through more translucent materials. Resin-based cements have excellent shading options and can offer flexibility when esthetics matter most.

5. Esthetics

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In your practice, it may well be that you have a go-to cement for most of your cases. But are there times when your go-to is not the best fit? The reason different cements are available is because they’re made differently for indications with varying requirements.

Having multiple cements on hand may seem like overkill, but it does pay dividends. Every patient is different, and you can give every individual the best treatment possible by taking his or her unique needs into account.

Each cement has different advantages, and updates are frequently made to what’s available in the market. As always, with new materials being steadily introduced to dentistry, continued vigilance in your cementation protocol is vitally important. That being said, having a simplified cement system already in place can streamline the selection process in your practice.

*Note: Up to a veneer thickness of 1.5 mm (non opaque shades). A dual cure cement is recommended for thicker/more opaque veneers.

Cement Selection Matrix

Single Unit Restorations(crown, inlay, onlay, veneer)

Metal/PFM Zirconia Glass Ceramics Composite Material

Retentive Prepe.g. crowns with 3-4 mm axial height

Non Retentive Prep/Small Bonding Surfacee.g. inlay, veneer* or veneer

cementor veneer cement

Conclusion

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Zirconia is growing in popularity, especially as advancements are made to give the material better esthetics. The best option for bonding zirconia is a self-adhesive resin cement like RelyX Unicem 2 because it’s a simple, one-step cement that will provide excellent strength and esthetics.

This checklist will help you make sure you’re getting the most out of your zirconia restoration.

Pre-treat The Restoration Material

Bonus: Checklist for Zirconia Cementation

Abrading a zirconia crown with 30 to 50 micron aluminum oxide prepares and energizes the zirconia surface to optimize adhesion and bonding to functional groups of the cement.

Understand the chemistry

Cleaning after try-in is important so that no contaminants exist on the crown surface that could interfere with the bond and cause the crown to fall off. Use a 5% sodium hypochlorite solution on a cotton pellet to wipe the internal surface of the crown, rinse and air dry.

Take the time to mechanically clean the tooth surface (e.g. a pumice paste). This necessary step helps to remove residual temporary cement, astringents, or anything else that might contaminate the tooth surface. For best bonding results and patient comfort, leave the surface slightly moist (shiny, glistening).

Implement a cleaning protocol

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After seating the restoration with RelyX Unicem 2 cement under light finger pressure, tack cure with an LED curing light for 1-2 seconds and remove excess cement with a scaler while holding the crown in place. Don’t exceed the recommended tack cure time, otherwise cleanup could be difficult. If you tend to over cure, or if you don’t have a light with a tack cure option, there are two alternative methods:

1. Remove the cement immediately in the soft stage with a microbrush/sponge, and cover the edges of the restoration with glycerin gel to prevent oxygen inhibition.

2. Wait about 3 minutes for the cement to gel and remove the cement in one piece.

Set yourself up for successful removal

The restoration itself may be the star of the show, but the cement can make or break it. RelyX Unicem 2 cement has multiple shade options so that you can match the appearance of the overall smile. Chemistry plays a role in esthetics as well; RelyX Unicem 2 cement ensures the color stability and resulting esthetics of zirconia, because the cement’s final, neutral pH reduces water uptake and staining.

Don’t forget about the esthetics

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3M Oral Care2510 Conway AvenueSt. Paul, MN 55144-1000 USA1-800-634-2249

Phone 1-800-634-2249Web 3M.com/dentalcements

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