The aim of the study was to evaluate the effect of titanium bone fixations on mitochondrial activity, reactive oxygen species (ROS) production, glutathione metabolism, and selected markers of oxidative/nitrosative stress in the periosteum-like tissue of patients treated with mandible fractures. The study group consisted of 30 patients with bilateral fractures of the mandible body eligible for surgical treatment. Our study is the first one that indicates disturbances of mitochondrial activity as well as a higher production of ROS in the periosteum-like tissue covering titanium fixations of the mandible. We also found significantly higher levels of reduced glutathione and enhanced activity of glutathione reductase in the periosteum homogenates of patients in the study group compared to the control group. Levels of nitrosative (S-nitrosothiols, peroxynitrite, nitrotyrosine) and oxidative stress biomarkers (malondialdehyde, protein carbonyls, dityrosine, kynurenine, and N-formylkynurenine) were statistically elevated in periosteum-like tissue covering titanium fixations. Although exposure to titanium fixations induces local antioxidant mechanisms, patients suffer oxidative damage, and in the periosteum-like tissue the phenomenon of metallosis was observed. Titanium implants cause oxidative/nitrosative stress as well as disturbances in mitochondrial activity.

Background/Objectives: The objective of this study was to analyze the profiles of sphingosine (Sph), sphinganine (SPA), sphingosine-1-phosphate (S1P), and ceramides (C14 Cer, C16 Cer, C18:1 Cer, C18 Cer, C20 Cer, C22 Cer, C24:1 Cer, and C24 Cer), along with caspases (CAS-3, CAS-6, and CAS-9), in serum and in the periosteum of the maxilla and mandible in patients with dentofacial deformities undergoing treatment with titanium fixations (miniplates and miniscrews). Methods: The study group comprised 20 patients who underwent bilateral jaw osteotomy due to dentofacial deformities. The osteotomy segments were stabilized with titanium alloy miniplates and screws. The control group consisted of 20 patients who had not yet received surgical treatment for maxillofacial defects. Results: Sphinganine (SPA) and ceramide C22 (C22 Cer) were the only compounds found to be significantly elevated in the serum of the study group compared to the control group. The concentrations of Sph, SPA, C14 Cer, C16 Cer, C18 1 Cer, C18 Cer, C22 Cer, C24 1 Cer, C24 Cer, and S1P were significantly lower in the maxillary periosteum of patients in the study group compared to those in the control group. The concentration of C20 Cer was significantly higher in the maxillary periosteum of patients in the study group compared to the control group. In contrast, the concentrations of Sph, SPA, C14 Cer, C16 Cer, C18 1 Cer, C22 Cer, C24 1 Cer, and C24 Cer were significantly lower in the mandibular periosteum of the study group compared to the control group. The concentrations of C20 Cer and S1P were significantly elevated in the mandibular periosteum of patients in the study group compared with the control group. The activity of CAS-3 was significantly higher in the mandibular periosteum of patients in the study group compared to those in the control group. Conclusions: Titanium fixations induce local changes in the sphingolipid profile within the periosteum of the maxilla and mandible, while no systemic impact on this metabolism was observed.