Balancing Opacity and Translucency for Life-Like Esthetics
Two cases showcasing IPS e.max® pressable materials
Selecting the appropriate material for restoring a patient’s smile is the most important decision the dental team makes when diagnosing and evaluating a case. Whether fabricating and seating a single crown or an entire arch, the responsibility for determining if patients smile with confidence or hide their smile in public rests with the dental team.
One of the biggest challenges in this process is finding a balance between opacity and translucency when restoring a patient’s smile. A highly opaque material will block all light, preventing the dark color of the dentin from escaping underneath. However, highly opaque materials will not absorb sufficient natural light for the restorations to appear “alive.” Light transmission over the entire restoration is just as important as the translucency in the incisal edge. Translucency is critical in creating life-like restorations. Faced with a dark stump color, many technicians choose an opacious ingot or coping and build it up extensively by segmenting powders in multiple layers. Such an approach is not appropriate for patients with an under- or end-on-end bite.
Finding the ideal balance between opacity and translucency can be difficult. Often the result is a reduction of value in the restorative material followed by a balancing act of complex porcelain layering. Beautiful porcelain buildups are great for patients who never bite their nails, participate in sports, or bite into something hard. Whether a layered porcelain or refractory restoration, flexural strength is, generally speaking, only in the 100 MPa range, which can compromise the integrity of the incisal edge.1 Even though patients are instructed how to protect these restorations and what to avoid, they often forget and resume their former habits.
Fortunately, dental professionals today have myriad choices when it comes to selecting the appropriate material for the case indication. The case examples presented here highlight the use of IPS e.max® pressable materials (Ivoclar Vivadent, www.ivoclarvivadent.com), which exhibit both strength (400 MPa) and natural-looking esthetics.2 For technicians and dentists who mill chairside, it has become increasingly important to have a material that can deliver natural-looking esthetics without spending excessive time on fabrication. When selecting a material, fabricating the restoration, and delivering it to the patient, clinicians consider all the finite details of creating a beautiful restoration that will blend seamlessly in the mouth with predictability and without making compromises with strength.
Case 1
A 67-year-old male patient presented with crowns on teeth Nos. 6 to 11 (Figure 1). The patient’s primary complaint was the esthetics of his smile and he desired a more esthetic and youthful appearance. The treatment plan provided by Zachary Gilbertson, DMD, called for replacing all six crowns. The clinician had prepared the teeth as conservatively as possible with careful consideration given to the underlying dental issues of interproximal caries and the old, compromised restoration interfaces (Figure 2). The photographs of the preparations sent to the laboratory along with the prescription showed that the underlying dentition post-preparation appeared very dark on teeth Nos. 6, 7, and 10. No additional buildup had been used to block out the darkness of the preparations nor did the final restorations contain light cure opaque. The desire was to assure strength and an integral bonded link between dentition and the restoration, shade A1.
The darkness of the preparations and the patient’s desire for a highly esthetic outcome posed a challenge for the author. To aid in material selection, darkened preps were simulated on the model (Figure 3). IPS e.max LT Ingots would solve the problem of hiding the dark preparations, but they were not translucent enough to achieve an esthetic final result. IPS e.max HT ingots would have been an exceptional choice had this case called for for ultra-thin translucent restorations. Value Ingots, which with their medium translucency have been the staple of many smile studios, would have solved most of the issues surrounding this case. However, there still would have been esthetic compromises.
Then the author considered the use of the newest addition to the IPS e.max line, the IPS e.max Multi. This pressable has the strength of 400 MPa from cervical margin to incisal edge, is bondable, and offers a shade gradient from the chroma and opacity of the cervical half to translucency in the incisal (Figure 4).
The incisal value can be raised and lowered for more or less translucency as needed by placing the wax sprue higher or lower on the sprue base. The sprue base is specially designed to receive the sprues, which are provided in two different forms. The Form A is used for upper anterior restorations and molars and Form B for lower anteriors. Mark Harper of Smiles, Inc. waxed and invested the six crowns. The dentist and patient were pleased with the final outcome (Figure 5).
Case 2
The patient was a 48-year-old woman who desired a white smile that looked natural (Figure 6). The treatment plan from Randy Furshman, DDS, called for placing six maxillary crowns on teeth Nos. 6 to 11. For restoring this case, the author chose to use the IPS e.max Multi-Press BL2 shade with minimal internal effects. Often working with the brighter shades is difficult for patients who want white teeth that look natural and not fake.
The author pressed the restorations in the EP5000 pressing furnace using the proprietary IPS e.max Multi pressing program. The surface detail of the wax-up was captured in great detail in the pressed restorations and the reaction layer was minimal. The restorations were cut away from the sprue using an end-cutting disc to minimize head buildup (Cardinal Rotary Instruments, www.cardinalrotary.com). A red pencil was used to mark the margin and the internal surface was checked with lipstick (Figure 7) to show the texture of the teeth. Then a stone wheel was used to refine the mesial interproximal area where the sprue was applied to the restoration and the margin was polished on the die. The author smoothed out the surface with a medium round bur.
Surface texture is applied more aggressively to create secondary anatomy using a tapered diamond and a spiral bur, and then polished to remove any sharp angles or excessive grooves.
IPS e.max Ceram Shade Incisal 2 was used to help absorb light along the incisal one third and Essence E18 anthracite was placed to separate the mamelon effect and mimic the translucent effect of the halo. E05 Copper and two parts E20 rose were blended and placed where the gum tissue would come in contact with the IPS e.max crowns to reflect the life of the tissue into the restoration. E02 Crème Essence was used for the light reflective portion of the halo and also a small amount was used to warm up the cervical center of the tooth (Figure 8). The restorations were then fired in the Programat P500/P510 using the Shade and Essence firing program.
After firing, Glaze Paste was placed in a mixing bottle. One third of the paste was introduced into the mixing container and one drop of glaze medium was added and the two mixed together. The Glaze was placed over the restorations in excess then removed until the brush strokes appeared to remain and then slowly disappeared, giving a smooth surface (Figure 9). The crowns were fired again on the Programat P500/P510, this time using the IPS e.max Glaze program. The author then ran a soft diamond over the glazed surfaces to smooth out any rough areas and polish the crowns to the dentist’s desired texture. The high shine was brought back with a high shine disk (Figure 10) and delivered to the patient (Figure 11).
Conclusion
Replicating a porcelain buildup, IPS e.max Multi-Press features a homogenous gradient pressing block that allows technicians and dentists to concentrate their time on the finite details of life-like esthetics. Dental professionals no longer have to spend years observing the influence of 15 to 30 bottles of porcelain to begin to understand where the true passion of creating beauty lies. After pressing, all that is left is to add the touch of an artist.
About the Author
Dane Barlow
Chief Operations Officer
Director of All Ceramics
Smiles, Inc.
Boise, Idaho
References
1. McLaren EA, Margeas R, Fahl N. Question: where and when is it appropriate to place monolithic vs. layered restorations? Inside Dentistry. 2012;8 (8):40.
2. Kang SH, Chang J, Son HH. Flexural strength and microstructure of two lithium disilicate glass ceramics for CAD/CAM restoration in the dental clinic. Restor Dent Endod. 2013;38(3):134-140.
