Effects of Four Different Crown Materials on the Peri-Implant Clinical Parameters and Composition of Peri-Implant Crevicular Fluid
This study aimed to identify the preferred crown material by measuring the peri-implant clinical parameters and the concentrations of receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), and calcium in peri-implant crevicular fluid (PICF) with 4 different crown materials. A total of 196 patients with a single missing posterior tooth received crown restoration with cobalt-chromium (Co-Cr) porcelain-fused-to-metal (PFM; n = 50), aurum platinum (Au-Pt) PFM (n = 48), titanium (Ti) PFM (n = 52), or zirconia (Zi) all-ceramic crown (n = 46). Fifty-one natural counterpart teeth served as controls. Before and 12 months after restoration, the PICF was collected, and the concentrations of RANKL, OPG, and calcium were quantified. The peri-implant clinical parameters (plaque index, bleeding on probing, and probing depth [PD]) and gingival crevicular fluid (GCF) volumes were assessed. Twelve months after restoration, the PD and GCF volumes for the 4 experimental groups were significantly greater than those for the control group and before restoration. The Co-Cr group showed the greatest PD, GCF volume, RANKL/OPG, RANKL, and calcium ion concentration, followed by the Au-Pt group. The Ti group had the highest OPG concentration, followed by the Zi group. The RANKL and calcium ion concentrations of the Ti and Zi groups were the smallest. The Ti group had the smallest RANKL/OPG ratio, followed by the Zi group. Different crown materials differentially affected the PD, volume, RANKL/OPG ratio, OPG, RANKL, and calcium concentration. Among the 4 tested crown materials, Zi and Ti are preferred. However, some limitations of the present study should be considered.
Figure 1. Comparison of (a) plaque index and (b) bleeding index among the different crown material groups before and after crown restoration. There were no significant differences between the groups (P > .05). Figure 2. Comparison of probing depth among the different crown material groups before and after crown restoration. *P < .05 for the comparison with other groups during the same period. #P < .05 between before and after crown restoration in the same group. Figure 3. Comparison of gingival crevicular fluid volume among the different crown material groups before and after crown restoration. *P < .05 for the comparison with other groups during the same period. #P < .05 between before and after crown restoration in the same group.
Figure 4. Comparison of osteoprotegerin (OPG) concentration among the different crown material groups before and after crown restoration. *P < .05 for the comparison with other groups during the same period. #P < .05 between before and after crown restoration in the same group. Figure 5. Comparison of RANKL among the different crown material groups before and after crown restoration. *P < .05 for the comparison with other groups during the same period. #P < .05 between before and after crown restoration in the same group. Figure 6. Comparison of receptor activator of nuclear factor-κB ligand/OPG among the different crown material groups before and after crown restoration. *P < .05 for the comparison with other groups during the same period. #P < .05 between before and after crown restoration in the same group. Figure 7. Comparison of calcium concentration among the different crown material groups before and after crown restoration. *P < .05 for the comparison with other groups during the same period. #P < .05 between before and after crown restoration in the same group.
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