Abstract

Aim and objectives: Discoloured teeth represent a challenge for any dentist. Minimally invasive prosthetic reconstruction in these particular cases, aiming for top aesthetics might frequently be almost impossible or not? Covering the discoloured teeth implies the use of an opaque ceramic that also needs to reproduce the translucency of the natural teeth. The balance between these two objectives is difficult to reach and involves multiple try-ins. In this in-vitro study, a comparison of the blocking ability of ceramic lithium disilicate ingots was evaluated. Material and methods: The ceramic ingots used were divided in three groups, depending on the degree of translucency/ opacity: LT (low translucency), MO (medium opacity), HO (high opacity). In each group, three different thickness veneers were designed: 0.4 mm, 0.6 mm and 0.8 mm, that were applied on two different shade abutments: one was the control group, ND1, and the other one, ND9. The colour was registered with the VITA Easy Shade V spectrophotometer and also clinically determined by 3 examiners. Results: Veneers designed from LT ingots registered significant colour differences in all three thickness cases. For MO ingot veneers, 0.8 mm thickness proved to be more efficient in covering the darkest colour of the abutment. HO ingot veneers, even in a 0.4 mm thickness offered a complete coverage of the abutment colour. Conclusion: Dark colour abutments can be completely covered by the lithium disilicate veneers in cases of MO ingots with 0.8 mm thickness. A question arises in terms of adhesion, due to dentin exposure secondary to tooth preparation. For HO ingots, the dark colour is completely covered by the 0.4 mm thickness, but, unfortunately, the final aesthetic results are no longer satisfying.

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