Serum TNF-α level and probing depth as a combined indicator for peri-implant disease

Peri-implant disease (PID) is a general term for inflammatory diseases of soft and hard tissues that occur around implants, including peri-implant mucositis and peri-implantitis. Cytokines are a class of small molecule proteins, which have various functions such as regulating innate immunity, adaptive immunity, and repairing damaged tissues. In order to explore the characteristics and clinical significance of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and tumor growth factor (TGF)-β1 expression levels in serum of patients with peri-implant disease, 31 patients with PID and 31 patients without PID were enrolled. The modified plaque index (mPLI), modified sulcus bleeding index (mSBI), and peri-implant probing depth (PD) were recorded. The levels of serum TNF-α, IL-6, IL-10, and TGF-β1 were detected by ELISA. TNF-α, mPLI, mSBI, and PD levels were significantly higher in the PID group. TGF-β1 levels were significantly higher in the control group. There was a significant positive correlation between TNF-α and mPLI, mSBI, and PD. TGF-β1 was negatively associated with TNF-α, mPLI, mSBI, and PD. Multiple logistic regression analysis showed that TNF-α and PD were risk factors for the severity of PID. The receiver operating curve analysis showed that high TNF-α levels (cut-off value of 140 pg/mL) and greater PD values (cut-off value of 4 mm) were good predictors of PID severity with an area under the curve of 0.922. These results indicated that TNF-α and PD can be used as a biological indicator for diagnosing the occurrence and progression of PID.