Dental Articles

Edentulous Mandible Reconstruction Using Zirconia Frameworks

Minnesota based laboratory, Renstrom Dental Studio, presents its Summer Featured Case Study. 

Cases as complicated as this one require excellent communication between the dentist, patient, and lab, to achieve the best possible outcome. Factors such as finances, stability, future risks, esthetics, and also level of difficulty are all taken into consideration when deciding on a solution for the patient.

For this particular case, an existing lower denture was to be replaced by three PFM bridges supported by six dental implants. Custom titanium abutments were milled by Atlantis and returned to Renstrom for fabrication of the bridgework.

Due to the wide span and large vertical dimension, a massive amount of metal would be needed to fabricate the three frameworks, resulting in very heavy dental restorations and exorbitant metal costs for the dentist.

Zirconia frameworks were suggested to reduce the weight and dramatically reduce the metal costs. The dentist benefits by reducing lab fees and the patient will have a much lighter and more esthetic fixed bridges in their mouth.

Renstrom crown and bridge technician, Lori Johnivin, starts the process by doing a full contour wax up of the complete lower arch. A soft tissue model is used to establish the proper pontic-ridge relationship and emergence profile.

A matrix is constructed of the wax up so that the contours can be established when the porcelain is built up. Lori sections the wax- up and does a cut-back leaving the proper space for porcelain. The cut-back wax -ups are sent to Minnesota Dental Millings to be duplicated in zirconia. The milled zirconia frameworks are returned to Renstrom for application of porcelain

Before applying porcelain, ceramist Angela Henrichs must determine which porcelain system she will use to create the most natural and esthetic result. Pre-treatment photos of the patient are very helpful at this point.

As Angela uses different dentins, enamels, pinks, effect powders, and clear or natural porcelains, she carefully builds each section in layers. Angela says, “I like to create bone, papillas, root, and tissue from the very start, just as it is in nature.” She prefers to fire some layers individually because it gives her more control over shape and color.

For example, in order to achieve a clear appearance at the gingival sulcus, she outlines a bead of clear and then fires it. Angela uses photographed images of real tissue and teeth as a guide as she attempts to mimic the natural appearance of teeth and soft tissue. Textures and lusters are different on the tissue area than on the teeth, so Angela uses many different methods to create just the right look.

The detailed process used to build the tissue is shown in the photos that follow. Recon- structions like this one require a high standard of communication and teamwork. At Renstrom, our laboratory technicians work hard to apply these standards to every case, large or small. Inside this issue:

RENSTROM RADIANT RESTORATIONS 

Featured Case Study 

1. Custom titanium milled abutments
2. 3M Lava Zirconia frameworks
3. Sectioned wax-up after cut -back
4. Gingiva pink zirliner is applied to the tissue area and fired. To add depth, certain areas are high- lighted with internal stains and modifiers.

 

1. Three pink porcelain shades are applied to the tissue to establish a baseline. Stippling effects are added at this time as well.
2. Different enamels and pink porcelains are used to better define the contours of the tissue.
3. Translucent and clears are added to the sulcus area. The finished tissue is hand polished in order to control the different high and low lusters. 
4. After photo of the patient with lower cemented zirconia bridges over titanium dental implant abutments. Both doctor and patient were very pleased with the final smile makeover result. 

• Case Study is from Renstrom’s Summer Newsletter – Read more stories

• Previous Renstrom dental lab newsletters

• Renstrom is a Northern Dental Alliance Member

• Visit Renstrom.com

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