Andrea L. Hegedus, Great Lakes Smile Design Studio

Earlier this year, I competed in the first North American 

 “Art of Denture” competition featuring Candulor’s “Swiss art of Prosthetics” and Camlog’s “perfect fit” implants.

The primary assignment was to complete a maxillary full denture and a removable mandibular bar retained full denture using the Gerber lingualized set-up method. The second part of the assignment was to document the procedures used to produce the submitted design for the competition.
	I received third place overall and second for digital presentation.

 and duplicated models to complete the prosthetics. The patient was a 72-year-old female who had worn dentures for 28 years. She suffered from poor fitting dentures and complained about problems with her speech, chewing, sore spots and the unnatural look of her anterior teeth. Upon radiographic examination, four Camlog implants were placed in the anterior mandibular bone.

The case was articulated to an average value with the right condylar inclination set to 32° and the left condylar inclination set to 36°. The anterior set-up was set in a natural, slightly irregular arrangement with the facial surface of the 

 corresponding to the plaster bite rim. The artificial gingiva shade was instructed to be fully customized and contoured.

Once the case was mounted, I evaluated the models and began to design the fully customized implant prosthetic. This is my assessment of the case:

 A maxillary lab putty guide was made to transfer the facial-buccal corridor, the midline, cuspids and smile window from the plaster wall 

. The mandibular lab putty guide was made to not only transfer the over-jet and facial surface of the mandibular teeth, but also as an incisal-buccal cusp index for the smile line of the maxillary teeth.

, in relationship to the plaster wall, the facial midline mark shows the patient’s left side is going to be proportionately smaller and require extra attention to detail to make the symmetry of the smile from left to right look the same.

 I began the smile design by setting the two centrals first to 

, facial support of the lip, envelope of function, and incisal length of the smile line. The cuspids were set next to complement the symmetry of the smile line. Their placement was in correlation to the palatine fovea and the cuspid marks from the plaster wall 

 To complete the anterior group, the laterals were adjusted in shape, size and slightly rotated to fit into the final smile line. Once the uppers were finished, the lower anteriors were set starting with the cuspids and centrals followed by the laterals 

. Protrusive movement and the patient’s over-jet was designed to fit within the parameters of the lab putty guide so the facial surface would support the lower lip during function.

 To begin setting the posterior teeth the lower first bicuspid and the lower first molar were given the most attention. The occlusal forces were measured by using the Static Laser to place the central cusp directly over the ridge for optimal stability.

 The Occlusal Compass also was used to map out the masticatory unit; lowest point on the ridge, and the posterior-anterior rise of the ridge 

. The masticatory unit is the key player in posterior stability. There should not be any occlusal forces distal to the posterior rise of the mandibular ridge. Any teeth set past this point should not be in function or they will create displacement of the prosthetic. With implant retained it is easy to avoid this rule because of the increased stability they provide to the prosthetic. However during lateral movements the implant prosthetic will suffer severe breakdown. Ridged ceramic material can shatter and flexible acrylic/composites crack, chip or will completely separate from each other. The masticatory unit is very important to maintain and is double checked with the Occlusal Compass and Static Laser when setting the posterior teeth for a second time over the implant framework 

 When the posterior teeth were initially set, a lab putty guide of the set-up was made to help guide the fabrication of the implant framework design 

. I chose to use a High Nobel cast bar and clip design with two custom made locators for the prescribed removable design 

. Mini clips were used in the narrow anterior region of the bar and the mini locators were placed slightly lingual under the lower first bicuspids. This design allowed for easy maintenance of the prosthetic over time. The chosen clips and locator housing can be replaced chairside with pick-up light-cured acrylic by creating an occlusal window in the acrylic base, making them visible once the prosthetic is seated in place for the procedure. This gives visible reassurance to the practitioner of the alignment of the new clips and locator housing caps to the implant bar without disturbing the harmonious occlusion, the occlusion we all worked so hard to establish.

 I used Candulor’s Aesthetic Color Denture Wax, shade 34 for the wax base, shade 57 for the alveolar mucosa, shade 55 for the fixed gingiva and shade 53 for the marginal gingiva 

. The Aesthetic Color Wax Set was easy to use as long as the denture base, shade 34, was not over contoured. Using the colored wax helped establish a color pattern for the final multi-layered colored heat-cured acrylic.

 The final wax-up was flasked for heat-cured acrylic and hand packed under pressure. After the boil out process, the mold was prepared with separator and the colored acrylics were layered in by hand with the same matching color shades as the Aesthetic Wax.

 Once the heat-cured acrylic was cured, the flasks were cooled for divesting. The prosthetics were then remounted to verify the occlusal function.

 It is very important to calibrate the masticatory unit one last time. You can see in the final photos how the patient’s right side was set in cross-bite to follow the patient’s alveolar ridge and buccal wall. This made the working side function more like the balancing side so it was important to make sure there was contact on the first bicuspid 

. Therefore when the patient’s right side was in balancing, it functioned more like a working side wall 

 So, let’s take a look at the patient’s left side 

. It was set with lingualized occlusion to correspond with the Static Laser, profile compass, and lab putty guides for the buccal. To achieve working and balancing, the fossa of the second premolar and the first molar are positioned lingually so the palatal cusps of the first premolar and the molar make contact in the fossa.

 To complete the assignment, the PhysioStar teeth and denture base were prepared for customization. I used Candulor’s light-cured resin stains to enhance the natural appearance of the denture teeth 

. The stains also help to maintain the “new” denture feel when the patient comes in for routine hygiene visits. The denture base also can be maintained with the matching cold-cure acrylics.

 At last, the final prosthetic set was polished to a high gloss to seal the acrylic base pores for prevention of tartar and plaque build-up 

I entered the competition hoping to bring awareness of the rising need for highly skilled technicians in prosthodontics. The spirt of the competition has created a safe place where new ideas can be presented and a platform where the best of the best can come together to show their talents, inspiring others to achieve excellence in dentistry.

For information or to register for the next Candulor KunstZahnWerk

 competition at the 2013 IDS in Cologne, Germany go to 

Andrea L. Hegedus owns Great Lakes Smile Design Studio. She can be reached at 

Articles

Earlier this year, I competed in the first North American Candulor KunstZahnWerk® “Art of Denture” competition featuring Candulor’s “Swiss art of Prosthetics” and Camlog’s “perfect fit” implants.

The art of smile design

	Gold or porcelain-fused-to-metal (PFM) crowns traditionally have been considered the “go to” choice when strength and long-term function are needed from a restoration that can be fabricated predictably and easily. However, an innovative PFM one build powder (InLine One, Ivoclar Vivadent) was recently introduced to enable laboratory ceramists to enhance their productivity when fabricating crowns and bridges. The InLine One ceramic is based on a leucite-forming ceramic glass. Based on their homogenous structure, the leucite crystals contained in the glass matrix demonstrate a small grain size. As a result, laboratory technicians can benefit from the material’s workability, strength and luminosity when creating restorations that are gentle to opposing dentition.

	The patient presented with a fractured lower second molar that required endodontic treatment (i.e., root canal) and a crown (Fig. A). A PFM restoration featuring a new one-layer ceramic (In-Line One) in Vita Shade A1 was indicated.

 Two sets of quadrant models (e.g., white and blue) were used to fabricate the single crown restoration. The white set was the “clean design” model (i.e., except for exposing the margin, no adjustments were made), which ensured the true, proper fit of the restoration design and a pleasing final presentation. This clean set was used to check contacts and occlusion without being hinged together; articulating the models by hand through their occlusal excursions provides an unrestricted perspective (Fig. B). The blue set, which serve as the “dirty working” models, are hinged together to facilitate waxing, building, adjusting and tapping in the occlusion.

 From start to finish, it is important to follow the proper techniques-from metal design to porcelain layering. Starting with a full wax-up that can be referenced using both sets of models is the best approach for creating a baseline throughout the case (Figs. C, D and E). All clearance and anatomical design should be worked out in the wax-up, ensuring that it coincides with the substructure and layering ceramics. Any preparation reductions or opposing adjustments should be made during the wax-up stage, allowing sufficient time to ask the prescribing doctor for permission.

 A snap putty mold was made and used as a reference guide for waxing the pattern design of the metal substructure (Fig. F). For optimal light reflection, refraction and laminating strength, the selected ceramic material (InLine One) requires a minimum thickness of 0.8 mm and a maximum thickness of 2 mm (Fig. G). Therefore, it was necessary to ensure the substructure design followed the cusp fossa relationship that was built into the occlusion (Fig. H). The wax-up design also served to control the harmonious gradient of color throughout the entire restoration from the inside out, so the wax margin was cut back for a small porcelain margin.

 Using a lost wax technique, the wax pattern was invested and cast. A high noble metal, white gold based dental alloy (Sagittarius, Ivoclar Vivadent) was used. The casting was fitted, requiring only minor adjustments, and was cleaned by blasting with alumina oxide. It then was run through a degassing cycle in preparation for porcelain application (Fig. I).

 The oxidized metal substructure was opaqued with shade A1 by first applying a wash layer (Fig. J), then fired a second time at 930°C with a full-coverage opaque layer to block out any metal color. In this case, a porcelain margin was required, which was applied in two separate firings. Because the InLine One materials are fully compatible with all powders from the conventional InLine product line, standard margin materials can be used. Because the margin materials and opaquers can be fired at the same temperature, the thin areas of opaque could be touched up at the same time (Fig. K).

 Once the margin was complete, the remainder of the crown was built using the Dentcisal 1 powder, after which the restoration was fired at 910° C (Fig. L). The restoration demonstrated some shrinkage after the first build and required a second build with more Dentcisal 1 powder, after which it was fired at 900° F (Fig. M). This decision was based on a comparison of the build-up to the wax-up to ensure the proper shape and occlusal cusp to fossa relationships had been established. Internal characterization stains can be used to modify the shade prior to the second build, but they were not required for this case.

 The final anatomy was scribed in using a highspeed 701 carbide fissure bur. A clear glaze was then applied to the entire restoration (Fig. N). Although it wasn’t required for this case, external characterization stains can be used to enhance the shade.

	When fabricating these types of crowns, the shade is controlled mostly by the color of the selected opaque. InLine One Layering Dentcisal powders allow the opaque to shine through the layers, producing a harmonious shade from the inside out (Fig. O). For opaque layers to exhibit magnificent reflections, the substructure must complement the final design. If the restoration requires more fluorescence, opaque F can be applied prior to the Dentcisal build-up.

	The InLine One system is easy-to-use and enables technicians to focus on the shape of their crown restorations. It also is ideal for technicians looking to advance from gold crown waxing to porcelain building. Additionally, the system shows great promise for easing first-time bridge builders into less complicated layering techniques. Because the InLine One system delivers uncompromised esthetics, it represents an ideal alternative for technicians who prefer to hand layer their crowns, rather than press to metal.

Andrea L. Hegedus, CDT, BS, owns Great Lakes Smile Design Studio in Muskegon, Mich. Building a career in dentistry over the last 25 years, she completed a Bachelor of Science with Honors in Prosthodontics from Ferris State University in 1990, is an active member of the American Academy of Cosmetic Dentistry, Francis B. Vedder Study Club, NADL, and MACDL and has completed numerous courses with PAC-Live at the University of Pacific Dental School and with The Hornbrook Group at the University of Texas, Houston Dental Branch. She also has studied under ceramic masters, Matt Roberts, Marv Staggs, Oliver Brix, Michel and Inge Magne, and leading dentists, Drs. Mark Montgomery and Ron Ritsco. Contact her at 

 Gold or porcelain-fused-to-metal (PFM) crowns traditionally have been considered the “go to” choice when strength and long-term function are needed from a restoration that can be fabricated predictably and easily.