Clinical results of lithium-disilicate crowns after up to 9 years of service

The purpose of this prospective study was to evaluate the clinical outcome of anterior and posterior crowns made of a lithium-disilicate glass–ceramic framework material (IPS e.max Press, Ivoclar Vivadent).

A total of 104 single crowns were placed in 41 patients (mean age, 34 ± 9.6 years; 15 male, 26 female). Eighty-two anterior and 22 posterior crowns were inserted. All teeth received a 1-mm-wide chamfer or rounded shoulder preparation with an occlusal/incisal reduction of 1.5–2.0 mm. The minimum framework thickness was 0.8 mm. Frameworks were laminated by a prototype of a veneering material combined with an experimental glaze. Considering the individual abutment preconditions, the examined crowns were either adhesively luted (69.2 %) or inserted with glass–ionomer cement (30.8 %). Follow-up appointments were performed 6 months after insertion, then annually. Replacement of a restoration was defined as failure.

Four patients (10 crowns) were defined as dropouts. For the remaining 94 crowns, the mean observation time was 79.5 months (range, 34–109.7 months). The cumulative survival rate according to Kaplan–Meier was 97.4 % after 5 years and 94.8 % after 8 years. Applying log rank test, it was shown that the location of the crown did not significantly have an impact on the survival rate (p = 0.74) and that the cementation mode did not significantly influence the occurrence of complications (p = 0.17).

The application of lithium-disilicate framework material for single crowns seems to be a reliable treatment option.

Crowns made of a lithium-disilicate framework material can be used clinically in the anterior and posterior region irrespective of an adhesive or conventional cementation when considering abutment preconditions.