To analyze and compare the curative effect of flap and flapless surgery on the outcomes implant treatment, and to provide the basis for clinical rational selection of implant surgery.

PubMed, Cochrane Library, Web of Science and Embase database were searched to find the related literature about the effect of flap and flapless surgery on the outcomes of implant treatment. The searching time was from the establishment of the databases to September 1st, 2021. The literature was retrieved by Medical Subject Headings of Dental implants, Surgical flaps, Surgery, and their hyponyms. The literature was screened strictly according to the inclusion and exclusion criteria, and evaluated for their quality. The effects of flap and flapless surgery on the outcomes of implant treatment were extracted as available data, including the number of failed cases, operation time, inflammation, swelling, modified plaque index (MPI) , modified sulcus bleeding index (MSBI) , probing depth (PD) , verbal analogue scale (VAS) , implant stability quotient (ISQ) , crestal bone loss, mesial bone loss, distal bone loss, mesial and distal bone loss after immediate loading. Odds ratio (OR) or mean difference (MD) and 95% confidence interval (CI) for efficacy indicators were calculated by RevMan (v.5.3) . Sensitivity analysis and publication bias test were performed for studies with heterogeneity using StataSE (v.12.0) .

A total of 24 studies were included in this study, including 1 124 cases of flap and 1 184 cases of flapless surgeries. The results showed that MSBI[OR = -0.12, 95% CI (-0.22, -0.01) , P = 0.03], PD[OR = -0.21, 95% CI (-0.25, -0.17) , P<0.001], VAS[OR = -0.39, 95% CI (-0.60, -0.19) , P = 0.000 2], crestal bone loss[OR = -0.11, 95% CI (-0.18, -0.03) , P = 0.007] after flapless implant surgery were significantly lower than those of flap surgery (P<0.05) . The number of failed cases, MPI, ISQ, mesial and distal bone loss after immediate loading were not significantly different between the flap and flapless implant surgery (P>0.05) .

The incidence of pain after flapless implant surgery was significantly lower than that after flap surgery, and the gingival bleeding, periodontal pocket depth and crestal bone loss after loading were significantly less than those after flap surgery. In clinical work, appropriate implantation method should be selected according to the soft and hard tissue conditions of the case, and flapless implant surgery has more advantages than flap surgery.