Immediate Implant Placement in the Esthetic Zone: A Multi-Variate Analysis of Influencing Factors

To evaluate the dimensional reduction of the peri-implant hard tissues and esthetic outcome after immediate implant placement (IIP) in the esthetic zone.

Patients who received IIP with bone grafts in the esthetic zone, with either immediate or delayed restoration, were included in this retrospective cohort study. The implants were categorized into three groups based on the labial bone thickness (LBT) before implantation: Group 1 (≤ 0.5 mm), Group 2 (0.5-1 mm), Group 3 (≥ 1 mm). The horizontal bone loss (HBL) at 0, 3, 5 mm apical to implant shoulder, peri-implant marginal bone loss (MBL), and Pink Esthetic Score (PES) were used to evaluate the hard and soft tissue after IIP.

A total of 87 implants in 74 patients met the inclusion criteria. Compared to group 3, there was significant severe bone loss in the HBL-0 mm in groups 1 (p = 0.017); and the implant located in the central incisor position and female may led to increased bone resorption (p = 0.021, p = 0.061, respectively). For HBL-3 mm and HBL-5 mm, the non-immediate restoration may reduce bone resorption (p = 0.013, p = 0.022, respectively). The MBL during short-term follow-up and PES score showed no significant difference among three groups.

Despite limitations, our study found that LBT < 0.5 mm significantly affected horizontal bone loss. Meanwhile, immediate restoration, implant position of central incisors and female may also be considered as risk factors for HBL. However, the difference in the labial bone did not significantly affect MBL, or peri-implant soft tissue outcomes.

This study was registered in a clinical trial registry (www.chictr.org.cn, No: ChiCTR2400087990).