Technical Advice

When perfection is in the details, it pays to be particular. The best restorations and dental prosthetics usually occur when both the dentist and the lab each have full details on the anticipated result and case outcome. That’s why creating clear, precise and complete instructions is absolutely critical to success. When you begin planning your case, providing your lab with the most thorough case details is the most important advice we can offer for achieving the perfect case outcome.

As anterior restoration options are improving, patient expectations are heightening too. With more lighter and whiter choices available, patients are requesting more perfection in the color of their restorations. The conventional PFM feather-edge margin has been the gold standard for decades. However, we have been advising our customers to routinely prescribe all upper anteriors be fabricated with porcelain butt margins. This eliminates the possibility of grayness (margin line) in the gingival area. Shoulder preparations are required for this type of restoration; however, the margin’s aesthetics are vastly improved for a reasonable cost.

Try not to stretch yourself too thin. The increase in the availability of cosmetic materials has left us to believe that we can now fabricate ultra-thin veneer type restorations using a ceramic reinforced substructure while still maintaining translucency and esthetics. This is only possible if all conditions are optimal. It is important to note that these restorations still require a minimum of 1.2 mm reduction to consistently achieve good aesthetics. What happens when you don’t? Let’s look at some examples:

• A Procera® core with less than 1 mm reduction will not produce good aesthetics.
• A Cercon® core with less than 1 mm reduction will not produce good aesthetics.
• A Lava® core with less than 1 mm reduction will not produce good aesthetics.
• Other re-enforced substructure materials will not produce good aesthetics.

Even though ultra-thin restorations are metal-free, the color and translucency will still require sufficient reduction and will physically mask the support materials. The best advice we can offer for the ultra-thin restoration is to prescribe an all-ceramic material (Empress I, IPS Empress II, Finesse All-Ceramic or other similar products). These products require bonding, but can provide the aesthetics needed for the thinnest of restorations.

There’s no better time for a good impression than the first time. We understand the difficulty in setting up another appointment, re-anesthetizing the patient and taking a new impression, but occasionally, we have to request another attempt so we can fabricate the perfect restoration for your patient.

The key is to create the best possible impression the first time. The impression is the foundation for a successful restoration and selecting the right tray for your case is critical. The single most important advice is to provide clear and precise impressions with all necessary details. The best impressions are usually obtained by using a heavy body with wash technique or by creating a custom tray. Here are the most common techniques:

1. The most common type we see is a triple tray technique. However, additional care must be taken when using the triple tray due to the impression material’s tendency to flow outward rather than inward (like the hydraulic forces created by using a custom tray). This can result in missed details and areas that pull away. Want a quick fix? Try this – sufficiently filling the tray and massaging the cheek prior to the full set can usually eliminate the difficulties associated with this hydraulic outward “flow.”
2. The custom tray technique provides the dentist the most consistent results thanks to the hydraulic forces created by the inward compression of the materials. This pressure drives the material into the impression details needed for ideal results. Helpful hint – after the initial seating, pressure must be released to allow the impression materials to relax prior to the complete set, otherwise “snapback” can result and the prosthesis could be smaller and tighter than necessary.
3. The wash technique is also popular because it eliminates the need for a custom tray. However, this method is even more susceptible to “snapback” than the custom tray. Avoid “snapback” with this technique by first using a #4 round bur to drill through the heavy body and create a “snapback” vent prior to taking the wash. This allows the light wash materials to relax prior to the complete set.

Wondering which tray and material is best for your case? Consult a DDS Lab technician.

We’re perfectionists when it comes to fit, which is why we provide an adjustment service that is quick and accurate for our customers. This service can include the following: adding contacts, occlusion adjustment, shade modifications and more. You can avoid adjustment returns and the need for extra chair time by verifying that the patient’s temporaries fit well without applying pressure to the adjacent or opposing dentition. We adjust many cases that are perfect on the models; however, the final outcome for the patient requires adjustments anyway. Our best advice is to carefully inspect your temporaries for accuracy. Avoiding the conditions below will also help prevent difficulties when seating crowns.

• Temporaries with tight contacts. They will equal open contacts when the crown is seated.
• Temporaries with loose contacts. They will equal tight contacts when the crown is seated.
• Temporaries with high occlusion. They will equal moved, shifted teeth, soreness, etc.
• Temporaries with low occlusion. They will equal high occlusion when the crown is seated.

Let’s face it. Shading is a subjective process. Explaining translucencies and colors to another individual is difficult, even with tools and shade guides. While a shade tab tells us to approximate the “hue,” the “chroma” and the “value,” it does not tell us about blending or other subtle differences. A picture is always helpful because it allows us to determine the blending — plus many other attributes of the existing dentition. So our advice is to include a picture whenever possible. Just send us a hard copy or transmit one electronically. When taking these pictures, always include a white piece of paper in the photo. This allows us to better overcome color discrepancies and color correct the photo — making it a whole lot easier to provide the perfect shade. To read more about shade-matching, check out our TeckTalk: Shade Matching in Restorative Dentistry