Abstract: PURPOSE: To explore and compare the clinical effects of delayed implantation and immediate implantation after minimally invasive extraction. METHODS: Eight-six patients from Nanjing Tongren Hospital who underwent minimally invasive extraction of the upper and lower mandibular anterior teeth and premolars from April 2013 to April 2018 were randomly divided into the control group and the experimental group. Forty patients in the control group were treated with delayed implantation after minimally invasive extraction, while 46 in the experimental group underwent immediate implant treatment after minimally invasive extraction. The success rate of the two groups of patients was compared, and the implant stability, the depth of probing around the implant, the aesthetic effect, and the bone level at the edge of the implant and the satisfaction after follow-up were recorded 3 months after implantation and at the day of permanent repair. The data were analyzed using SPSS 20.0 software package. RESULTS: After treatment, the success rate of the control group was 100%, and the success rate of the experimental group was 100%(P>0.05). The ISQ of the 2 groups 3 months after implant placement and at the day of permanent repair had no significant difference(P>0.05); the depth of probing around the implants in the experimental group was smaller than that in the control group, but the difference was not significant(P=0.80); the total satisfaction of the experimental group was greater than that of the control group, and the difference was statistically significant (P=0.044); one year after repair, the gingival nipple index was in grade 1-3, the soft tissue shape was good, all achieved good gingival aesthetic effect, the difference between the two groups was not significant(P=0.66). PES score of the control group was 7.65±1.32, and 8.25±1.19 in the experimental group, the difference was significant (P<0.05). There was no significant difference in the amount of bone absorption both in the mesial and distal sides between the two groups (P>0.05). CONCLUSIONS: After minimally invasive extraction, both immediate and delayed implant placement can achieve good clinical results. Although all the implants have good stability,immediate implantation has higher satisfaction, better aesthetic effect and good clinical application prospects.

Key words: Minimally invasive extraction, Delayed, Probing depth around the implant, Immediate implantation, ISQ