CAD/CAM-fabricated ceramic implant-supported single crowns made from lithium disilicate: Final results of a 5-year prospective cohort study

Abstract

Background

All-ceramic bilayer systems suffer from technique-sensitivity, resulting in increased technical complication rates. This might be overcome by monolithic reconstructions, facilitating digital workflows.

Purpose

To evaluate the clinical and patient-reported outcome of CAD/CAM-fabricated implant-supported single crowns (ISCs) made of lithium disilicate (LS₂) cemented on ceramic implants 5 years after implant installation.

Materials and methods

Twenty-four patients were included in the study. All participants received a one-piece ceramic implant in anterior (4 incisors) and posterior regions (10 premolars, 10 molars). LS₂ crowns were computer-aided designed (CAD), manufactured (CAM) and adhesively luted onto the implants. Follow-ups were performed yearly up to 60 months after implant installation. The survival/success rates of the restorations were calculated according to modified US Public Health Service criteria as follows: Clinically relevant defects that could be repaired intraorally were accepted for survival, whereas small-area chippings, roughness (ø < 2 mm), slightly soundable marginal gaps, minimal undercontours/overcontours, and tolerable color deviations were accepted for success. Kaplan-Meier plots were used for the success/survival analyses. Furthermore, patient-reported outcome measures (PROMs) were assessed by applying visual analog scales (VAS). Linear (PROMs) and logistic (USPHS criteria) mixed models were fitted to evaluate time effects on response variables.

Results

Twenty-two ISCs could be evaluated 55.2 ± 4.2 months after prosthetic delivery. Two patients were reported as drop-outs (1 died, 1 moved abroad). No failures were observed, resulting in 100% survival. At two ISCs, a major-roughness had to be treated. This resulted in a Kaplan-Meier success estimate of 91.7% (95%CI: 70.6%-97.9%). Compared with pretreatment, all surveys at prosthetic delivery except for self-esteem (P = .375) showed significantly improved VAS scores. No decrease in satisfaction could be observed over time until the end of follow-up (P ≥ .056).

Conclusion

Concerning survival/success rates and PROMs, the evaluated crown-implant system showed favorable mid-term results. To date, there are no comparable data available for implant-supported ISCs made of LS₂.

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