Abstract: Objective To investigate the clinical application of minimally invasive extraction and immediate implant replacement and compare the differences between immediate implant and delayed implant. Methods 127 patients(127 singletooth implants) were included in this research. After the complete examination 127 teeth in the maxillary anterior region were extracted without flap reflection and 59 implants were replaced immediately，68 implants were replaced after alveolar ridge preservation. The day when stagetwo operation was done， gingival contour was induced using implantsupported temporary crowns prior to restoration till permanent prostheses delivered. The periimplant bone level and probing depth were measured immediately after the permanent restoration and 3，6，12 months later the clinical effect was evaluated. Results The implant stability quotient (ISQ) value of the 2 groups showed no significant difference before permanent restoration(P>0.05). The PD of the 2 groups also showed no significant difference(P>0.05).In all the cases after loading 1 year， the periimplant bone loses of the immediate group and delayed group in the mesial side were (0.37±0.34) mm and (0.39±0.43) mm respectively， while in the distal side were (0.41±0.31) mm and (0.43±0.32) mm respectively. All these indicators showed no significant difference between the 2 groups(P>0.05). Conclusions Both the protocols can achieve great therapeutic effects. And the therapy of minimally invasive extraction and immediate implant replacement is a sensitive technique through which patients can shut down their treatment time and acquire great aesthetic effect. To obtain ideal results， the operators need to be trained professionally and control the indications strictly.

Key words: minimally invasive extraction, immediate implant replacement, alveolar ridge preservation