Implant stability and marginal bone level changes: A 2-year prospective pilot study

Background/purpose: Implant stability is crucial for successful osseointegration. Marginal bone level is considered an important indicator of long-term implant success and stability. The purposes of this study were to investigate 1) the effect of age, gender, bone density, implant length, and implant diameter on insertion torque (IT), primary implant stability quotient (ISQ), and secondary ISQ, 2) the impact of age, gender, bone density, implant length, implant diameter, IT, and ISQ on marginal bone loss (MBL). Materials and methods: Ninety patients who needed implant therapy were enrolled and overall 156 implants were installed to support single crowns. IT and ISQ were recorded for all implants during surgery and ISQ measurements were performed at follow-up visits. Age, gender, bone density, implant length and diameter were also registered. Radiographic evaluation of MBL was performed postoperative immediate (baseline), 3, 6, 9, 12, 18, and 24 months using digital periapical radiographs. Results: Age had little effect on IT and primary ISQ (P > 0.05). Generally, males had higher IT and primary ISQ, but no significant differences between genders were detected. Bone density showed significant effects on IT and primary ISQ. Correlation analysis revealed high positive correlations between IT/bone density and primary ISQ/implant diameter. Significant impacts of bone density and IT on MBL were found. Conclusion: Implant diameter had a more profound impact than length on IT/primary ISQ. Bone density played a considerable role in IT/primary ISQ determination. Bone density and IT had more impacts than primary ISQ on MBL.