Study of Immediate Implants Placed in Mandibular Alveolar Bone Reconstructed with Screw-Guided Bone Regeneration Technique: A 24-Months Follow-Up

Aim: Study aimed to test whether implants inserted in posterior mandible sites augmented with screw-guided bone regeneration (S-GBR) technique differ from implants placed in non-grafted sites regarding the success and survival rate. Materials and Methods: 20 edentulous patients (mean age 59.45 +/- 15.220) were divided in a test group (S-GBR) (immediate implants placed simultaneously with grafting procedures) and control group (implants placed in naturally healed sites). Primary outcomes (implants success; implants survival) and secondary outcomes (clinical parameters of soft tissues: mPI; mGI; probing depth; keratinized mucosa; marginal-bone-level) were evaluated at 24-months follow-up. Results: Plaque levels were higher (p = 0.046) in S-GBR group (0.97 +/- 0.882 mm) when compared with control (0.66 +/- 0.695 mm). Keratinized mucosa width was higher in S-GBR group (4.13 +/- 1.033 mm) than control (3.34 +/- 0.821 mm) (p = 0.000) Probing depth (PD) width was higher in S-GBR group (3.50 +/- 1.372 mm) than control (2.56 +/- 1.332 mm) (p = 0.000). mGI was higher among implants placed in S-GBR group (0.90 +/- 1.020 mm) than control (0.56 +/- 0.794 mm) (p = 0.061). The difference between the average bone loss (MBL) for implants placed in grafted sites (Group S-GBR: 2.20 +/- 1.867 mm) and for those placed in naturally healed sites (Group B: 1.09 +/- 1.678 mm) was statistically significant (p = 0.000). The overall implant success rate after 24-month follow-up was 76.7% in S-GBR group and 90.6% in control group (p = 0.001). The survival rate after 24-month follow-up was 86.7% in S-GBR group and 93.8% in control group (p = 0.182). The reconstruction of the alveolar bone using S-GBR technique and immediate implant placement is a valid guided bone regeneration strategy for mandibular alveolar bone with severe horizontal resorption. The choice of S-GBR technique should be based on specific indications as implants placed in grafted sites recorded worse marginal success rate, survival rate and bone resorption than those placed in non-grafted sites.