Objective To investigate the effect of self-etching bonding system on the repair of elderly dental defects with severe attrition and its effect on dentin sensitivity. Methods In this study

120 elderly dental defects with severe attrition diagnosed and treated in a hospital in Dalian from June 2017 to October 2020 were selected as the research subjects. The patients were randomly divided into study group（n=60） and control group（n=60）. The patients in the control group were treated with total acid etching bonding repair system. The patients in the study group were treated with self-etching bonding repair system. The USPHS（United States Public Health Services） scores of the two groups were compared at 1 week

1 month and 3 months after treatment. The tooth sensitivity was compared between the two groups at 1 week and 3 months after treatment. The joint noise（JN）

Craniomandibular dysfunction index（DI）

palpation index（PI）

masticatory muscle and related muscle palpation（MP）

craniomandibular index（CMI）

mandibular movemln（MM） and joint pressure（JP） of Friction index before treatment and 3 months after treatment were compared between the two groups. The scores of OHRQoLUK（Oral Health-Related Quality of Life-UK） before treatment and 3 months after treatment were compared between the two groups. Results One month and 3 months after treatment

the scores of masticatory function

gastrointestinal function

dentition appearance

pronunciation and mental psychology in USPHS of the two groups were higher than those of 1 week after treatment

and the scores of the study group were significantly higher than those of the control group（P<0.05）. One week and 3 months after treatment

the rate of dentin sensitivity grade C in the study group was 3.33% and 1.66% respectively

which was lower than 21.67% and 11.67% in the control group

and the difference was statistically significant（P <0.05）. Three months after treatment

the scores of CMI

MP

DI

JN

PI

MM and JP in the Friction index of the two groups were lower than those before treatment

the scores of the study group were lower than those of the control group

and the difference was statistically significant（P<0.05）. Three months after treatment

the physiological

psychological

social and total scores of OHRQoL-UK in the two groups were higher than those before treatment

and those in the study group were significantly higher than those in the control group（P<0.05）. Conclusion The application of self-etching bonding repair system in elderly patients with dental defects with severe attrition can better promote the repair of dental defects

reduce the occurrence of postoperative dentin sensitivity

and improve the function of temporomandibular joint

which can improve patients’ quality of life and is worthy of clinical application.