Abstract: Objective To explore the clinical effect of onlays made by chairside economic restoration of esthetic ceramics(CEREC) digital all-ceramic restorative system for the restoration of severely worn teeth in the elderly. 
Methods The clinical data of 92 elderly patients with severe worn teeth(92 teeth in total) were selected for retrospective study. According to different restoration schemes and patients' wishes, they were divided into control group and research group, with 46 cases in each group. The control group was repaired with traditional hot-pressed porcelain, and the research group was repaired with CEREC digital all-ceramic restorative system. The impression preparation time, success rate of one-time tooth wearing, restoration effect, restoration satisfaction, incidence of adverse events, masticatory function before and after restoration, quality of life ［oral health impact profile-14(OHIP-14)］, oral health index ［simplified calculus index(CI-S),simplified debris index(DI-S)］ were compared between two groups. 
Results The time of impression preparation in the research group was shorter than that in the control group, and the success rate of one-time tooth wearing(100.00%) was higher than that of the control group(86.96%)(P＜0.05).The edge fitness, gum health, and restoration loosening or the success rate of shedding(95.65%, 93.48%, 100.00%) were higher than those of the control group(82.61%, 78.26%, 86.96%)(P＜0.05). Compared with those before repair, the masticatory efficiency of the two groups was significantly improved at 6 and 24 months after repair, and higher in the research group than in the control group(P＜0.05). The OHIP-14 scores of the two groups at 6 and 12 month safter repair were lower than those before repair , and lower in the research group than in the control group(P＜0.05). Compared with those before repair, the CI-S and DI-S scores of the two groups were significantly reduced at 6 and 12 months after repair, and lower in the research group than in the control group(P＜0.05). The incidence of adverse events(6.52%) was lower in the research group than in the control group(21.74%)(P＜0.05).The scores on the comfort, appearance, masticatory function and satisfaction with overall treatment experience were higher than those in the control group(P＜0.05). 
Conclusion Onlay made by CEREC digital chairside all-ceramic restorative system in the treatment of elderly patients with severely worn teeth can achieve better restoration effects, which can reduce the incidence of related adverse events, and further improve the masticatory function, oral hygiene and quality of life of patients, with good patient satisfaction.

Key words: tooth wear, CEREC digital chairside all-ceramic restorative system, onlay restoration