Search Results (98)

This study aimed to evaluate mandibular fixation techniques using monocortical plates following sagittal split ramus osteotomy in skeletal Class III patients. Ninety-three patients were categorized into three groups based on fixation methods: four-hole miniplate with one proximal and two distal screws (Group 1); four-hole miniplate with four screws (Group 2); sliding plate with two proximal and one distal screws (Group 3). Cone-beam computed tomography scans were obtained at three time points: immediately postoperative (T1), 6 months (T2), and 12 months (T3). The yaw, roll, and pitch rotations of the proximal segment, as well as horizontal and vertical changes of the pogonion, were evaluated. Group 1 exhibited significantly greater counterclockwise rotation of the proximal segments at T2 (p = 0.021) and T3 (p = 0.035) compared to the other groups. Additionally, Group 1 showed significantly smaller anterior and superior displacement of the pogonion at T3 (0.97 ± 2.10 mm, p = 0.009; 0.03 ± 1.62 mm, p = 0.011, respectively). Following surgical wafer removal, intimate occlusal contact is archived and the elimination of premature contacts through postoperative orthodontic treatment contributes to counterclockwise autorotation of the mandible. Therefore, anterior and superior movements of the pogonion are expected if firm fixation between the proximal and distal segments is achieved. Therefore, these findings suggest that a single proximal screw, as seen in a three-screw fixation, may act as a fulcrum, insufficiently resisting postoperative clockwise rotation of the distal segments. Full article

Background/Objectives: Patient-specific osteosynthesis (PSO) plates, in combination with virtual surgical planning (VSP), have significantly improved the accuracy of orthognathic surgery. This study aimed to compare the surgical accuracy of two-plate versus four-plate fixation methods in Le Fort I osteotomies using PSO. Methods: A retrospective cohort study was conducted on 21 patients who underwent maxilla-first bimaxillary surgery at a single centre in 2024. Eight patients received two-plate fixation, while thirteen received four-plate fixation. All surgeries were planned using VSP. Postoperative cone beam computed tomography scans were used to assess the accuracy of maxillary positioning by comparing the planned versus achieved outcomes in terms of translation and rotation. Results: Both fixation methods yielded comparable results in maxillary positioning, with no significant differences observed between the two groups regarding translational or rotational deviations. The two-plate PSO approach demonstrated practical benefits, including reduced material usage and the potential for smaller surgical incisions, without compromising surgical accuracy. Conclusions: Two-plate PSO fixation is a viable alternative to the traditional four-plate method for Le Fort I osteotomies, offering similar accuracy with potential procedural advantages. While these findings support broader clinical adoption, further research is warranted to confirm the results in larger cohorts and to investigate biomechanical considerations. Full article

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. Full article

The aim of the study was to evaluate the effect of titanium implants (Ti6Al4V) on the surrounding tissues by analyzing the concentration of titanium particles, TNF-α, and caspase-3 in patients treated for jaw fractures and dentofacial deformities. The research material consisted of peri-implant tissues: fragments of periosteum adhering to a titanium miniplate and blood serum collected from 42 patients treated for mandibular fractures (Group I), and dentofacial deformities (Group II) who underwent bimaxillary osteotomy. The control group consisted of 24 generally healthy patients before bimaxillary osteotomy. The concentrations of selected cytokines, caspase-3, TNF-α in blood serum, and homogenized tissues, were determined using the immunoenzymatic method (ELISA). The concentration of titanium particles was assessed using a scanning electron microscope equipped with an X-ray microanalyzer. A significant increase in the concentration of titanium, caspase-3, and TNF-α was observed in serum and periosteum in all patients who underwent bone fixation. Increased TNF-α levels indicate an intense immune response, which may lead to the degradation of peri-implant tissues and bone resorption around the miniplates and screws, while an increase in caspase-3 levels suggests that cells surrounding the implants are destroyed in response to inflammatory stress or damage induced by the presence of titanium particles. Full article

Titanium is widely recognized for its biocompatibility and utility in maxillofacial and orthopedic surgery; however, its influence on bone remodeling biomarkers remains underexplored. This study investigates the effects of uncoated titanium plates on both the growth factors and diacylglycerols (DAGs) in the periostea of the maxilla and mandible, as DAG signaling is an essential secondary messenger molecule involved in intracellular signaling connected to various growth factors. The study group comprised 20 patients undergoing bimaxillary osteotomies using miniplates and screws made of Ti6Al4V titanium, from whom bone fixations were removed, while the control group included 20 patients operated on for dentofacial deformities (before the insertion of titanium fixations). Diacylglycerol levels in the serum and periosteum were analyzed using tandem mass spectrometry coupled with ultra-high performance liquid chromatography. Growth factors in the periosteum were measured via ELISA with commercially available assay kits. Our findings demonstrate a significant reduction in growth factors, including IGF-1, PDGF, and FGF-23, alongside decreased total DAG levels, suggesting titanium plate stabilization may modulate bone remodeling dynamics. Notably, while overall DAG levels declined, specific DAG species such as C16:0/16:0 and C18:0/18:0 were elevated, whereas polyunsaturated DAGs showed reductions, indicating selective regulation of lipid signaling pathways. Correlation analyses highlighted complex interactions between growth factors and DAGs, with distinct regional differences observed in the mandibular and maxillary periostea. These alterations may result from chronic titanium exposure, potentially inducing a low-grade immune response or modifying the local biochemical environment. This study emphasizes the need for further research into the long-term effects of titanium implants, particularly their influence on lipid metabolism, growth factor dynamics, and bone healing. Full article

Objectives: Titanium miniplates and screws are commonly used in the surgical management of dentofacial deformities. Despite the opinion of the biocompatibility of these bone fixations, some patients experience symptoms of chronic inflammation around titanium implants even many years after their application. The aim of this study was to examine the levels of cytokines, chemokines, and growth factors released from the maxilla and mandible periosteum surrounding titanium fixations 11 months after the implantation procedure. Methods: From the study group (n = 20) consisting of patients with maxillofacial defects who underwent bimaxillary osteotomy, fragments of the periosteum of the maxilla and mandible adjacent to the titanium miniplates and screws were taken during routine bone fixation removal procedures. From the control group subjects (n = 20), fragments of healthy maxillary and mandibular periosteum were taken prior to surgical treatment of dentofacial deformities. The examination of cytokines, chemokines, and growth factors levels released from the periosteum of jaws was performed using the Bio-Plex Pro Human Cytokine Screening Panel (48-Plex). Results: The study group was characterized by a significant increase in the concentration of most of the tested-for proinflammatory cytokines/chemokines/growth factors compared to the control group, with greater amounts of inflammatory factors released from the periosteum covering the titanium implants in the mandible than from the periosteal cells surrounding the titanium implants in the maxilla. Conclusions: Prolonged exposure to titanium miniplates and screws leads to a disturbance of immune homeostasis in the periosteal cells of the maxilla and mandible. The data obtained indicate the need to remove fixations after the bone fragments have healed. Full article

The market for microinverters is growing, especially in Europe. Driven by rising electricity prices and an easing in legislation since 2024, the number of mini-photovoltaic energy systems (mini-PVs) being installed is increasing substantially. Indoor and outdoor studies of microinverters have been carried out at Paderborn University since 2014. In the indoor lab, conversion efficiencies as a function of load have been measured with high accuracy and ranked according to Euro and CEC weightings; the latest rankings from 2024 are included in this paper. In the outdoor lab, energy yields have been measured using identical and calibrated crystalline silicon PV modules; until 2020, measurements were carried out using 215 W_p modules. Because of increasing PV module power ratings, 360 W_p modules were used from 2020 until 2024. In 2024, the test modules were upgraded to 410 W_p modules, taking into account the increase from 600 W to 800 W of inverter power limits, which is suitable for simplified operation permission (“plug-in”) in many European countries within a homogenised legislation area for such mini-photovoltaic energy systems or “balcony power plants”. This legislation for simplified operation also covers overpowered mini-plants, although the maximum AC output remains limited to 800 W. Presently, yield assessments are being carried out in the outdoor lab, which will take at least a year to be valid and comparable. Kits consisting of PV modules, inverters, and mounting systems are also being evaluated. Yield rankings sometimes differ from efficiency rankings due to the use of different MPPT algorithms with different MPP approach speeds and accuracies. To accelerate yield assessment, we developed a novel, simple formula to determine energy yield for any module and inverter configuration, including overpowered systems. This is a linear approach, determined by just two coefficients, a and b, which are given for several inverters. To reduce costs, inverters will be integrated into the module frame or the module terminal box in the future. Full article

In reconstructive surgery following partial mandibulectomy, the biomechanical integrity of the fibula free flap applied to the remaining mandibular region directly influences the prognosis of the surgery. The purpose of this study is to evaluate the biomechanical integrity of two fixation materials [titanium (Ti) and hydroxyapatite/poly-L-lactide (HA-PLLA)]. In this study, we simulated the mechanical properties of miniplate and screw fixations in two different systems by finite element analysis. A three-dimensional mandibular model was constructed and a fibula free flap and reconstruction surface were designed. The anterior and posterior end of the free flap was positioned with two miniplates and two additional miniplates were applied to the angled area of the fibula. The masticatory loading was applied considering seven principal muscles. The peak von Mises stress (PVMS) distribution, size of fixation deformation, principal stresses on bones, and gap opening size were measured to evaluate the material properties of the fixation. In the evaluation of properties, superior results were observed with both fixation methods immediately after surgery. However, after the formation of callus between bone segments at 2 months, the performance of Ti fixation decreased over time and the differences between the two fixations became minimal by 6 months after surgery. The result of the study implies the positive clinical potential of the HA-PLLA fixation system applied in fibula free flap reconstruction. Full article

(1) Objectives: The purpose of this review was to compare the effects of combining skeletal anchorage and Class II devices, both from an overall perspective and individually for each type of appliance, considering as main outcomes the vertical dimensions and the inclination of the mandibular and maxillary incisors. (2) Materials and Methods: A search without time restrictions was performed up to February 2024 in PubMed, PubMed Central, Scopus, and Medline for randomized controlled trials, as well as prospective and retrospective cohort studies, considering Class II patients treated with and without skeletal anchorage. The effect measure used for the meta-analytic evaluation was the standardized mean difference (SMD). The SMD calculation was obtained by subtracting the mean values of T1–T0 for each individual treatment and then calculating the SMD between the treatments involved. The meta-analysis was performed using the standardized mean difference of the mean difference of the T1–T0 change in the outcome between the different treatments evaluated as the effect size. (3) Results: A total of 1217 documents were initially retrieved. According to the PRISMA protocol, 18 studies comparing different skeletal anchorage protocols (upper/lower miniscrews and miniplates), combined with four appliances (Herbst, Forsus, Carriere Motion, and elastics), were included in the analysis. No significant difference in skeletal divergence was found between groups from an overall point of view (SMD: 0.19 (−0.48 to 0.83) according to the random-effects model). A statistically significant reduction in IMPA° was found in patients treated with temporary anchorage devices (TADs) (SMD of 5.58 (3.40 to 7.75)), except for the elastics group (SMD: 3.76 (−0.91 to 8.43)). The effect on the upper incisors’ inclination appeared to be strictly dependent on the type of anchorage (TADs in one or both of the arches). Some limitations must be considered when interpreting the results: the small number of studies included and the heterogeneity among them are among the limitations, and the temporal disparity among some studies; the ages of the patients were not always comparable; and, finally, the clinical relevance of the effects of TADs is sometimes questionable. (4) Conclusions: The vertical dimension seems not to be significantly affected by skeletal anchorage; instead, the proclination of mandibular incisors is generally reduced when TADs are used. Skeletal anchorage might be useful if lingual tipping of the upper incisors is required; however, it is influenced by the anchorage protocol. Full article

Performance analysis of the adsorptive separation of ethylene downstream of an oxidative coupling of methane (OCM) process, being an alternative process for converting methane content of natural gas or other methane-rich sources to ethylene, was studied in this research for a production capacity of 1 Mt/yr. This was motivated by observing promising adsorption characteristics and efficiency in the selective adsorption of ethylene using 13X zeolite-based sorbent. The energy and economic performance of alternative scenarios for retrofitting the adsorption unit into an integrated OCM process were analyzed. Simulations of the integrated OCM process scenarios include OCM unit, CO₂-hydrogenation, ethane dehydrogenation and methane reforming sections. The use of efficient ethylene adsorption separation enabled the improvement of the economic and energy efficiency of the integrated OCM process under specific operating conditions. For instance, the invested amount of energy and the associated energy cost per ton of ethylene in the cryogenic ethylene-purification section of the integrated process using adsorption unit are, respectively, 75% and 89% lower than the reference integrated OCM process. Under the conditions considered in this analysis, the return on investment for the final proposed integrated OCM process structure using adsorption separation was found to be less than 9 years, and the potential for further improvement was also discussed. Full article

The open reduction of mandibular condyle neck fractures is difficult due to the limited surgical field and complex facial nerve structures. The most effective fixation method for narrow fractured segments is debated as standard double four-hole plate fixation is often not feasible. This research compared bone stability and force resistance between single-long-plate and double-short-plate fixations using clinical outcomes, a Sawbones mandible model, and finite element analysis. In patients with condyle neck fractures, nine were fixed with single-long-plate and twelve with double-short-plate fixations, with no significant differences in malocclusion and facial palsy rates. In compression tests with a Sawbones model, displacements in the posterior part were similar in both fixation groups. In contrast, the anterior part had significantly higher displacements in the single-long-plate group. Finite element analysis showed higher displacements in both anterior and posterior parts in the single-plate group compared to the double-short-plate group. Maximum stresses were at the second screw hole in single-long-plate fixation and the turning point of the upper plate at the condyle neck in double-short-plate fixation. Double-short-plate fixations demonstrated better stability and force resistance than single-long-plate fixations. Full article

Background/Objectives: The use of miniplates for stabilizing bones post orthognathic surgery has surged in popularity due to their efficacy in ensuring stability and hastening recovery. However, controversy exists regarding what should be done with these miniplates after surgery. Some surgeons advocate for their removal, while others suggest leaving them in place. This study sought to assess the frequency, causes, and potential risk factors linked with miniplate removal in orthognathic procedures. Methods: A thorough meta-analysis was conducted by scrutinizing studies from various databases including PubMed, Google Scholar, Embase, and Scopus, focusing on publications spanning from 1989 to 2023. Results: Ten studies meeting the inclusion criteria, encompassing 1603 patients, were chosen for inclusion in the meta-analysis. The male-to-female ratio varied from 0.7:1 to 4:1. Overall, 5595 miniplates were inserted, with 294 (5.3%) being subsequently removed. Primary reasons for miniplate removal included infection (161 cases, 2.9%), exposure of miniplates (34 cases, 0.6%), and palpable plates (23 cases, 0.4%). Other indications comprised pain, patient preference, and temperature sensitivity. Less frequent causes for miniplate removal included sinusitis, secondary surgery, and dental pathology. The mean duration of miniplate removal was 5.5 months, with the majority (56.1%) being removed from the mandible rather than the maxilla. In conclusion, this meta-analysis underscores the importance of miniplate removal when hardware causes complications and physical discomfort. The primary reasons for removing miniplates were infection and plate exposure, with the mandible being the most common removal site. Conclusions: These findings emphasize the need for continued monitoring to assess the fate of miniplates in orthognathic surgery and provide valuable information for future clinical decision-making. Full article

A novel H-shaped miniplate (HSM) was specifically designed for restorative laminoplasties to restore patients’ posterior elements after laminectomies. A validated finite element (FE) model of L2/4 was utilized to create a laminectomy model, as well as three restorative laminoplasty models based on the fixation of different miniplates after a laminectomy (the RL-HSM model, the RL-LSM model, and the RL-THM model). The biomechanical effects of motion and displacement on a laminectomy and restorative laminoplasty with three different shapes for the fixation of miniplates were compared under the same mechanical conditions. This study aimed to validate the biomechanical stability, efficacy, and feasibility of a restorative laminoplasty with the fixation of miniplates post laminectomy. The laminectomy model demonstrated the greatest increase in motion and displacement, especially in axial rotation, followed by extension, flexion, and lateral bending. The restorative laminoplasty was exceptional in preserving the motion and displacement of surgical segments when compared to the intact state. This preservation was particularly evident in lateral bending and flexion/extension, with a slight maintenance efficacy observed in axial rotation. Compared to the laminectomy model, the restorative laminoplasties with the investigated miniplates demonstrated a motion-limiting effect for all directions and resulted in excellent stability levels under axial rotation and flexion/extension. The greatest reduction in motion and displacement was observed in the RL-HSM model, followed by the RL-LSM model and then the RL-THM model. When comparing the fixation of different miniplates in restorative laminoplasties, the HSMs were found to be superior to the LSMs and THMs in maintaining postoperative stability, particularly in axial rotation. The evidence suggests that a restorative laminoplasty with the fixation of miniplates is more effective than a conventional laminectomy due to the biomechanical effects of restoring posterior elements, which helps patients regain motion and limit load displacement responses in the spine after surgery, especially in axial rotation and flexion/extension. Additionally, our evaluation in this research study could benefit from further research and provide a methodological and modeling basis for the design and optimization of restorative laminoplasties. Full article

Study Design: Systematic Review and Meta-analysis. Objective: This systematic review and meta-analysis aimed to compare the efficacy of 2 miniplates vs a three-dimensional plate in the management of mandibular condylar fractures. The primary objective was to assess key parameters, including intraoperative time, maximum mouth opening, complications, and functional outcomes, to determine potential differences between the 2 fixation methods. Methods: A comprehensive literature search was conducted to identify relevant studies. Inclusion criteria were applied, and the selected studies underwent systematic review. The key parameters were extracted and subjected to meta-analysis to quantify and compare the outcomes associated with the use of 2 miniplates and three-dimensional plates. The methodologies of the included studies were critically evaluated to address potential biases and confounding factors. Results: The meta-analysis results indicated that there were no statistically significant differences between the 2 fixation methods in terms of intraoperative time, maximum mouth opening, complications, and functional outcomes. However, concerns were raised regarding the high risk of bias, confounding factors, and considerable heterogeneity observed across the reviewed studies. Conclusions: The findings suggest that both 2 miniplates and three-dimensional plates are viable options for the management of mandibular condylar fractures. Despite the lack of statistical significance in the observed differences, the study highlights the need for further prospective research with enhanced methodologies, standardized protocols, larger sample sizes, and reduced bias to refine our understanding and potentially influence clinical management protocols. Full article

Study Design: This is a retrospective observational study. Objective: To evaluate the clinical outcomes after an open reduction and internal fixation (ORIF) of condylar neck and base fractures (CNBFs) with a trapezoidal shape plate in patients using a less invasive transparotid approach. Methods: Fifteen patients with condylar fractures were classified according to the Arbeitsgemeinschaft für Osteosynthesefragen Craniomaxillofacial (AOCMF) classification system, treated by ORIF with a trapezoidal plate. All patients were evaluated by clinical examination (pain, occlusion, and mandibular dynamics) and imaging through computed axial tomography. Postoperative evaluations considered a favourable clinical outcome of fragment stability, stable occlusion, absence of pain, and regular mouth opening ranges. In addition, any signs of local infection, malocclusion, facial nerve damage, or failure of the fixation system were recorded. Results: According to the AOCMF classification for condylar fractures, eight fractures affected the condylar base and seven involved the condylar neck. No patients presented pain or joint sounds in the TMJ. All patients obtained a buccal opening greater than or equal to 35 mm. Two patients showed postoperative malocclusion which was corrected by intermaxillary elastics therapy. In addition, two patients had transient paresis during the postoperative period. One of them had paresis of the frontal and buccal branches of the facial nerve while the second patient had paresis of the zygomatic and buccal branches. Conclusions: Using trapezoidal miniplates provides functionally stable fixation for neck and base condylar fractures and allows for a less invasive surgical transparotid approach (2 cm extension). They also reduce the amount of osteosynthesis material and are easier to adapt and fix in the author’s opinion. Full article