Does flap opening or not influence the accuracy of semi-guided implant placement in partially edentulous sites?

Objective: To investigate the effect of open-flap or flapless approaches on the accuracy of implant placement partially guided by tooth-supported surgical templates.

Materials and methods: A total of 36 edentulous sites were selected from seven human cadaver heads. Following the preoperative implant planning using Blue Sky Plan, surgical guides were fabricated by an in-office desktop 3D printer. All the sites were randomly divided into two groups: flapless approach (n = 18), and open-flap approach (n = 18). After guided osteotomy preparation with subsequent freehand implant placement, digital intraoral scanning was performed to obtain post-operative implant positions. Based on the image registration, the deviations between the planned and actual implant position were measured and compared.

Results: Statistically significant variance differences between the two approaches were found in the global coronal (open-flap: 0.86 ± 0.23 mm; flapless: 1.3 ± 0.62 mm; P < .001), global apical (open-flap: 1.38 ± 0.37 mm; flapless: 1.9 ± 0.78 mm; P = .002), and depth (open-flap: 0.59 ± 0.34 mm; flapless 0.89 ± 0.78 mm; P < .001) deviations. The differences were not significant regarding lateral (coronal and apical) and angular deviations.

Conclusions: In semi-guided implant surgery, the open-flap and flapless approaches demonstrate similar lateral and angular deviations. The open-flap group shows better depth control when manually inserting the implant.