Clinical outcomes of different types of tooth-supported bilayer lithium disilicate all-ceramic restorations after functioning up to 5 years: A retrospective study.
The aim of this retrospective study with large sample was to assess the 5-year clinical outcomes of four different types of restorations made from IPS e.max Press.



A total of 6855 restorations containing veneers (Vs), single crowns (SCs), 2-unit or multiple-unit combined crowns (CCs) and 3-unit or multiple-unit fixed dental prostheses (FDPs) from 4634 patients were included. Data collection were performed through scrutiny and registration of the records of all patients. The cumulative survival rates (CSRs) and their differences were calculated according to the Kaplan-Meier analysis and Log-Rank test. The differences among the failure rates of different restorations were evaluated according to the Chi-squared test.



The 5-year CSR of all restorations was 96.6%. The 5-year CSRs of CCs (94.4%) and FDPs (90.6%) were both significantly lower than those of SCs (96.5%) and Vs (97.2%). A total failure rate was 3.2%. The failure rate of FDPs was 9.0%, which was significantly higher than those of Vs (2.5%) and SCs (3.3%), and was similar to that of CCs (5.2%). The failure rate of molar SCs (8.2%) was significantly higher than those of anterior (3.2%) and premolar SCs (2.5%). 83.0% of failed restorations happened in the 1st year after cementation and 50.6% happened in the first 3 months. Moreover, ceramic chipping (41.5%) and fracture (37.3%) were the top two reasons. In anterior tooth region, the ceramic damage rate of Vs (1.7%) was significantly lower than those of FDPs (8.1%) and CCs (4.8%), and that of SCs (2.6%) was significantly lower than that of FDPs (8.1%).



IPS e.max Press has an ideal medium-term outcome. The failures mainly occurred in the first 3 months after cementation and the main reasons were ceramic chipping and fracture. Due to higher failure risk, we suggest dentists should be cautious to apply FDPs, CCs and molar SCs.
Department of Stomatology, Lanzhou General Hospital, Lanzhou Command of PLA, Lanzhou, Gansu, China.
Yanwei
Y
Yang
State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China; Department of Prosthodontics, College and Hospital of Stomatology, Anhui Medical University, Hefei, Anhui, China.
Jintao
J
Yu
State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
Jing
J
Gao
State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
Jiawen
J
Guo
State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
Ling
L
Li
State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China.
Yun
Y
Zhao
State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi, China. Electronic address: sfzhang@fmmu.edu.cn.
Shaofeng
S
Zhang
D002516:Ceramics; D003442:Crowns; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D003830:Denture, Partial, Fixed; D006801:Humans; D012189:Retrospective Studies
C493120:lithia disilicate; D003776:Dental Porcelain
Clinical outcomes; Cumulative survival rate; Failure rate; IPS e.max press; Lithilum disilicate