Clinical evaluation of chairside‐fabricated partial crowns composed of zirconia‐reinforced lithium silicate ceramics: 3‐year results of a prospective practice‐based study

OBJECTIVES: Prospective practice-based clinical evaluation of chairside fabricated monolithic partial crowns composed of zirconia-containing lithium silicate (ZLS) ceramic material. MATERIALS AND METHODS: Between October 2013 and September 2014, 71 patients were restored with 92 partial crowns on vital or sufficiently endodontically treated teeth. The monolithic restorations were fabricated chairside (Cerec SW 4.2/Cerec MC XL) from a glaze-fired ZLS ceramic material (Celtra Duo, Dentsply Sirona, Bensheim, Germany). Adhesive cementation was performed using the total-etch technique with one of two dual-curing composite materials. Modified United States Public Health Service parameters were evaluated annually; moreover, the parameters "time-dependent survival" (in situ criterion) and "success rates" (event-free restorations) were evaluated according to Kaplan-Meier analysis. RESULTS: Sixty-nine patients with 17 premolar and 71 molar partial crowns attended annual follow-up examinations (observational period: 36.0 +/- 5.7 months). Two complete failures were recorded and were caused by a tooth fracture (at 30 months) and a restoration fracture (at 38 months), (3-year survival rate: 99%; 95% confidence interval (CI 95%): [0.97;1]). One clinical intervention was necessary (endodontic treatment) to maintain function (3-year success rate: 98%; (CI95%: [0.95:1]). CONCLUSIONS: Chairside-fabricated ZLS partial crowns show a good initial clinical performance. However, to further evaluate this new material, clinical data from studies with longer observational periods are required. CLINICAL SIGNIFICANCE: Based on this mid-term evaluation, ZLS ceramics appear to be a promising alternative material for the chairside fabrication of adhesively luted monolithic posterior restorations with a low risk of material-related complications.