Effect of flapless surgery on single-tooth implants in the esthetic zone: a randomized clinical trial.

Background: Implant therapy is a highly predictable treatment option; however, insufficient data exist to show whether flapless implant surgery provides better esthetic outcomes and less bone loss than implant surgery with a flap approach.
Methods: In this randomized, controlled study comparing the flapless and traditional flap protocol for implant placement, 24 patients received a single implant in the anterior maxillary region. A cone beam computed tomography-aided surgical guide was used for implant placement surgery for both groups. Implants were restored using a one-piece, screw-retained ceramic crown at 3 months. Radiographic and clinical measurements were assessed at baseline (implant placement) and at 3 (crown placement), 6, 9, and 15 months. Clinical parameters evaluated were plaque index, gingival index, papillary index (PPI) (0 = no papilla, 1 = less than half, 2 = more than half but not complete, 3 = complete fill, and 4 = overfill), marginal tissue levels, biotype, width of keratinized tissue, and soft tissue thickness.
Results: Implant success rate was 92% in both groups. Mean PPI values for the flap control group and flapless test group were 2.38 ± 0.51 versus 2.31 ± 0.48 at crown placement (P = 0.68) and 2.52 ± 0.52 versus 2.64 ± 0.54 at 15 months (P = 0.42), respectively. PPI increased over time in both groups, although the flapless group had a significantly larger change in PPI from crown placement to 6 and 9 months (P <0.01). Crestal bone levels in the flap group were more apical in relation to the implant platform than those in the flapless group for the duration of the study. No differences among groups were noted for all other measurements.
Conclusions: Both flapless and flap implant placement protocols resulted in high success rates. A flapless protocol may provide a better short-term esthetic result, although there appears to be no long-term advantage.