Peri-implant tissue conditions at implants treated with Sub-periosteal Peri-implant Augmented Layer technique: A retrospective case series

Objectives: To assess peri-implant tissue conditions on the short term in patients receiving the Sub-periosteal Peri-implant Augmented Layer (SPAL) technique and in patients with adequate thickness (≥2 mm) of the peri-implant buccal bone plate (PBBP) at placement. Methods: Patients where either a dehiscence defect or thin PBBP at implant placement was corrected by SPAL technique (SPALdehiscence and SPALthin groups, respectively) and patients presenting a residual PBBP thickness ≥2 mm at implant placement (control group) were retrospectively selected. The number of peri-implant sites positive to bleeding on probing (BoP) at 6 months following prosthetic loading was the primary outcome. Also, height of keratinized mucosa, marginal soft tissue level, Plaque Index, peri-implant probing depth, suppuration on probing, and interproximal radiographic bone level (RBL) were evaluated. Results: Thirty-four patients (11 in the SPALdehiscence group, 11 in the SPALthin group, and 12 in the control group) were included. In each SPAL group, 10 patients (90.9%) showed peri-implant tissue thickness ≥2 mm at the most coronal portion of the implant at uncovering. The prevalence (number) of BoP-positive sites was 2, 1, and 0 in the SPALdehiscence, SPALthin, and control groups, respectively. RBL amounted to 0.3 mm in the SPALdehiscence group, 0.2 mm in the SPALthin group, and 0 mm in the control group. Conclusion: After 6 months of prosthetic loading, patients treated with SPAL technique show limited peri-implant mucosal inflammation in association with shallow PD and adequate KM. At implants receiving SPAL technique, however, interproximal RBL was found apical to its ideal position.