Sealing Capability of Implants With Titanium and PEKK Abutments
Objectives: The aim of this in vitro study was to investigate the sealing behavior of the implant-abutment interface of two-part dental implant abutment systems from newly introduced implant/abutment material combinations.
Methods: Two different implant/abutment material combinations were used: Yttria-stabilized zirconia (3Y-TZP)/polyether-ketone-ketone (PEKK) (Ceralog Hexalobe implants/PEKK abutments straight) and Grade 4 titanium/Grade 4 titanium (Camlog Screw-Line implants/titanium universal abutment, both Camlog Biotechnologies, Basel, Switzerland). These implant systems with conical implant-abutment connection and indexing were inoculated with lipopolysaccharide (LPS) sealed by the abutments and submerged in human whole blood (n=10). Positive-control blood samples (without implants) were stimulated with 400 μl/ml LPS, and implants without LPS served as negative controls (n=10). Changes in the gene expression levels of interleukin 1-ß (IL1-ß), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Toll-like receptor 4 (TLR-4), Toll-like receptor 9 (TLR-9), Fas-associated protein with death domain (FADD), and tumor necrosis factor-α (TNF-α) were assessed by real-time polymerase chain reaction (RT-PCR) analysis.
Changes in gene expression indicating LPS-leakage at the implant-abutment interface were detected in the Y-TZP/PEKK test group. Increased gene expression was detected after 8 h for TLR-4 (p≤0.05) and after 24 h for IL1-ß (p≤0.05) and NF-κB (p≤0.05). In the titanium/titanium test group, no changes in gene expression indicating LPS-leakage were detected. Before one-way analysis of variance (ANOVA) was performed, the data were tested positive for normal distribution by the Kolmogorov–Smirnov test. ANOVA was followed by a Bonferroni post hoc test.
Conclusions: The implant-abutment interface fabricated from Y-TZP and PEKK did not prevent microleakage on a molecular level, whereas a modified conical titanium connection prevented microleakage under the test conditions.