Evaluation of microgaps and microleakage at the implant-abutment interface of individualized abutments in the maxillary anterior region under functional loading: A pragmatic clinical trial.

PURPOSE: This study aimed to evaluate the effect of functional loading on microgaps and microleakage at implant-abutment interfaces (IAIs) in the aesthetic zone when using different abutments and to provide a clinical reference for abutment selection. METHODS: This study included 30 patients with 36 implants divided into three groups: zirconia (Zr)-one-piece custom abutment, titanium (Ti)-custom abutment, and Ti-original abutment. Scanning electron microscopy was used to examine alterations in the microgaps at the IAIs under functional loading. Changes in the bacterial endotoxin levels within the inner cavities of the implant were evaluated using a quantitative chromogenic Tachypleus amebocyte lysate test. These findings were subjected to statistical analysis using SPSS 18.0. RESULTS: Before functional loading, there were no significant differences in the microgaps between groups (P > 0.05). In the Zr one-piece custom abutment group, the lingual microgaps significantly increased after 24 months of functional loading (P < 0.05). The bacterial endotoxin content significantly increased after 24 months of functional loading compared to the pre-loading levels (P < 0.05); however, no statistically significant difference was observed among the groups (P > 0.05). CONCLUSIONS: Considering the limitations of this study, individualized one-piece Zr abutments exhibited a significant increase in lingual microgaps and comparable changes in microleakage to Ti abutments after 24 months of functional loading. Patients should be alert to the potential risks associated with the use of these abutments when they have heightened aesthetic expectations during functional loading.