A smart choice of framework material for full-colour control.
By Joachim Maier, MDT
Dental technicians have waited long for high translucent zirconias like Zolid FX. The natural light transmission enables us to reproduce natural esthetics with a low thickness of ceramics. A prerequisite, however, is the appropriate shade of the tooth stump substrate, one which has no negative influence on the shade result of the final restoration.
A young female patient was troubled by the discolouration of the devitalised tooth 11 and the inwardly inclined position of the two central incisors. The discoloured composite abutments on both teeth further intensified the patient’s desire to optimise her visual appearance (Figs. 2-3). Together with the patient, the dentist and I decided on crowning teeth 11 and 21 and reconstruction with all-ceramic crowns.
Masking the dark tooth stump
Due to the darker tooth stump 11, the dentist and I decided against the super high translucent Zolid FX in favour of the slightly less translucent Zolid HT+ (Fig. 4). The frame material was to reduce the influence of the dark stump at a wall thickness of approximately 0.5mm, such that the subsequent veneer layer could achieve an identical brightness value and remain stable even under different light sources. The different translucencies are represented in Figure 6b.
The frame is milled in Zolid HT+ White and adjusted to the desired dentin shade by applying the liquid staining technique before sintering. The frame shade selected was about half a shade lighter than the dentin of the veneer ceramics. This ensured a finely-dosed and sufficient light reflection in the depth of the tooth structure without unwanted greying at low light. The aim was to create vibrant-looking teeth with natural translucency, true colour depth and a reliable brightness value.
Intact canine guidance and diagnosed normal loading of the teeth allowed both labial and complete veneer of the growns. To do this, we used Creation CT.
Variations in shape
The dentist and I produced two different pairs of crowns. Varying the tooth width of the two crown sets by positioning the mesial and distal lines differently, the character of the teeth was changed.
Both variants were tried at two different appointments, and both sets match the patient’s face. After some minor changes, both pairs of crowns are completed. The choice of crown variation was decided by the patient. Figures 7-9 show the visually narrower variant, which fitted discreetly, inconspicuously and thus very credibly into the dental arch – this was my personal favourite.
The image sequence in Figs. 10-12 shows the second variant. These teeth appear bolder, larger and more rounded.
A matter of taste
At my courses and lectures, I presented both restoration variants to the expert audience and had them decide which execution they liked best. The majority voted in favour of the first variant. (Figs. 7-9)
The patient also opted for the second variant as she preferred the larger teeth. The selected pair of crowns were inserted and presented at the final photoshoot in Fig. 13.
Our goal was to fabricate prosthetics that pleased all parties involved. In this case, the patient was satisfied with the results of the crowning, making the restoration successful. We would also like to take this opportunity to thank Dr Julia Lorenz for the documentation, which made a significant contribution to the successful result.
Published in Dental Asia May/June 2022 issue.
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