Larsen-Chu Award Part 2

A very intensive patient live workshop with world-renowned speaker, MDT Patrick Rutten from Belgium, was on the agenda for the next two days. More than 40 years after a traumatic sport accident, the Dentist Dr. Jens Gebrande, discovered a circular caries lesion in a radiographic control under a post crown of an upper right central incisor (Fig. 1 and 2). The tooth was as not worth retaining and it was extracted. After a healing period of eight weeks, an implant was placed (Fig. 3). The delayed immediate implantation was combined with allogeneic bone augmentation and soft tissue regeneration with a free connective tissue graft harvested from the palate. Clinically, the course situation presented with an inserted implant in area 11. A healing abutment was screwed to the implant (Fig. 4).

Temporarily, the area was provided with a removable provisional. Due to functional aspects an individualized CAD/CAM-fabricated titanium abutment was chosen for the restoration. “When possible, I prefer not to use titanium in the front,” explained Rutten and added, „but in this case, function is more important than the aesthetics.” The challenge was  then to layer an all-ceramic crown on the zirconium dioxide coping with the VITA VM 9 veneering materials, giving the restoration the natural look of the neighboring teeth, and supporting the soft tissue due to successful gingiva management. “To work on a titanium abutment is very difficult. The gum can look greyish. We have to mask the greyish cervical part,” warned Rutten. The procedure was started with precise shade taking. He used the VITA Linearguide 3D-MASTER (Fig. 6). In the first step, the value was taken, followed by the chroma. Previously, the tooth basic color was also digitally measured with the VITA Easyshade V. Expert and digital advice, determined independently of one another, the color of 3M2 as the basic color of the dentin core. For Rutten “the basic color is the most important.”

As main part of their stay, the awardees participated in a competitive hands-on training, supported individually and intensively by the expert (Fig. 6a, b, c). For one and the same clinical situation four single crowns were fabricated by each participant and the expert (Fig. 7a, b, c, d, f). Finally, the best functional and aesthetic outcome was chosen to be cemented definitely. For the zirconium dioxide coping, Rutten recommended to do always a regeneration firing after try-in and fitting. The initial washbake firing is also a crucial step for Rutten, due to the non-fluorescent properties of the zirconium dioxide coping. “To start, I take a liner for fluorescence and a reliable connection to zirconia.” His layering procedure was carefully observed by the participants. The firing temperature of the VITA VM 9 EFFECT LINER should be 50 degrees higher than the normal dentine firing. 

Rutten made the decision to use a higher chroma in the cervical part with VITA VM 9 BASE DENTINE 3M3, to mask the delicate area and avoid the lifeless and greyish shine of the titanium abutment. The EFFECT CHROMA 4 (EC4), should support this masking to be continued with a deeper orange in the interdental areas with a mixture of EFFECT CHROMA 5 and 6 (EC5/6). For the upper third area, a higher value was selected with 3M2. To create the ridges, the blueish EFFECT ENAMEL 9 (EE9) mixed with ENAMEL Light was chosen (Fig. 8 a-f). According to Rutten, for the incisal edge, the synergy of the three basic components is vital:

• Color
• Enamel
• Translucency

A mixture of VITA VM 9 ENAMEL Light and EFFECT ENAMEL 9 (EE9) for a blueish accentuation, was determined. “I always take a little bit of EFFECT ENAMEL 9,” says Rutten. He uses this strategy to create natural light effects. In addition, VITA INTERNO 2 and 4 were mixed in to create warm sandy sunflower characteristics. For Rutten, VITA INTERNO powders play an important role in creating higher fluorescence and natural color effects from the inside: “For me, Internos are, very important. They are sunny and warm. I´m lost when you take away my Internos.” Characterizations should always be irregular to create a natural look. To achieve a contrast, BASE DENTINE was layered on the palatal side of the incisal edge. The layer was modeled with over plus to have enough material thickness during the intraoral functional grind-off procedure. The ceramic mixture must be creamy and stable and must stay in this creamy state. Rutten’s advice: “We need freedom on the implant crown. Function is the most important aspect!”

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“When you are missing volume, never use translucency in addition,” warned Rutten. “The effect is always the opposite. It is a mistake that I often see - too much enamel and too much translucency. The tooth will look greyish.” Based on that, he recommends again to use the BASE DENTINE (Fig. 8 and 9). If the value has to be changed, the technician should even gain two steps back with the basic value. “The basic value is for me the most important thing. You have to play with this.” (Fig. 9). The palatal side was planned to be layered with EFFECT CHROMA 4 and BASE DENTINE, avoiding a visible transition between coping and layering in these areas (Fig. 10). Rutten offers general advice for finding the right color combination. “Finding the right mixture sometimes takes more time than the layering itself. Don´t mix too much! Don´t start to mix thousands of powders!” (Fig. 13 to 15). 

“The gingiva needs a smooth surface,” Rutten tells the participants, in order to fabricate a homogeneous firing and a good polishing. “Especially in implantology cases, the dentist is sometimes fighting for every millimeter of healthy pink-colored gingiva.” Rutten knows the role of the dental technician from his clinical experience and encouraged the participants to create a supporting and compatible environment for the soft tissue. The shape of the neighboring tooth 21, was copied, keeping the support of the papilla in mind to avoid black triangles. The distal and mesial marginal ridges were created fluently to the apex localization with the help of a fine diamond bur. A chipped area was imitated according to the neighboring tooth, but not at the same space for a natural outcome. Due to that, a vertical crack line was also accomplished with a fine tungsten carbide bur: “You can move your cracks for two or three millimeters. We need an irregular crack line.” Polishing and contouring of concave areas took place with a rubber wheel. Final characterization was performed with VITA AKZENT Plus EFFECT STAINS. “I try to create something soft and not to overdo,” Rutten says of the final step.  

The course ended with an exciting try-in of four different and individual ceramic crowns before glaze firing (Fig. 16-24 ). Dr. Gebrande, a dentist from Bad Säckingen and of course the patient, chose the best work piece to be finalized and cemented definitely (Fig. 25-28). It was a really difficult decision. And as we know, everyone's tastes are different. In Rutten’s everyday practice, he has therefore a straight view on his work: “We have to be honest. I always want the best, but I can’t always reach it. What I want to reach is that the average quality of my work is higher than that of my neighboring lab. The goal should be to know when a tooth is finished, to fulfill also the economic aspects.” For every tooth, there has to be a consequent stopping point. “When you spend too much time looking at one tooth, you go nuts!” The patient in this special case was happy anyway. He was very pleased with the final aesthetic outcome. In addition he received three very beautiful compensational crowns. You never know …  

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To be continued: More pictures and details of the clinical case will be published soon. Follow us on Facebook! 
The next part of the Larsen-Chu Award will be announced on Facebook  . . .