Abstract
OBJECTIVES: This study aims to detect the levels of mucin (MUC)-4, metalloproteinase (MMP)-7, and MMP-8 in peri-implant crevicular fluid (PICF) and investigate whether the novel combinations of MMP-7 and MUC-4 are effective markers of peri-implant diseases, particularly when used in the PICF of healthy individuals, to provide a theoretical basis for finding a novel reference index that can aid the diagnosis, evaluation, and treatment of peri-implant diseases. METHODS: A total of 63 subjects with 2-5 years of upper prosthesis loading were selected according to inclusion and exclusion criteria, composed of 24 controls and 39 patients with peri-implantitis (PI) group. MUC-4, MMP-7, and MMP-8 levels were detected through enzyme linked immunosorbent assay (ELISA). RESULTS: No significant differences in age, sex, and other parameters were found between the PI and control groups. The PI group had higher MMP-7 and MMP-8 expression levels (P<0.05) but lower MUC-4 level (P<0.001). Correlation analysis showed that MMP-7 was positively correlated with pocket probing depth (PPD) (r=0.451, P<0.001); MMP-8 was positively correlated with PPD, bleeding on probing (BOP), and gingival index (GI) (r=0.619, P<0.001; r=0.478, P<0.001; r=0.332, P=0.009). MUC-4 was negatively correlated with PPD, BOP, and GI (r=-0.492, P<0.001; r=-0.321, P=0.010; r=-0.396, P=0.001). MMP-7, MMP-8, and MUC-4 had certain diagnostic efficacy for PI. MMP-8 exhibited the best diagnostic efficacy for PI. When the cutoff value of MMP-8 was >21.21, the area under the curve (AUC) was 0.868, and the sensitivity and specificity for the diagnosis of PI were 0.96 and 0.68, respectively. The diagnostic efficacy of MMP-7 and MUC-4 parallel diagnostic models was higher than that of each factor, and the diagnostic sensitivity of the model for PI was 0.96, and the specificity was 0.56. CONCLUSIONS: Differences in MMP-7 and MUC-4 levels were found between the inflammation and control groups and may be diagnostic indicators for predicting PI; combinations of MMP-7 and MUC-4 had a good diagnostic value for inflammation.