Effects of Biomineralization on Osseointegration of Pure Titanium Implants in the Mandible of Beagles.

PURPOSE: The purpose of this study was to investigate the effect of a biologically active dental implant surface (treated with sandblasting and acid etching [SLA] followed by immersion in simulated body fluid [SBF]) on osseointegration. MATERIALS AND METHODS: We randomly divided 9 healthy adult male beagles (aged 8 months; body weight, 12 kg) into 3 groups: machined, SLA, and SLA-biomineralization (SLA-Bio). Six pure titanium implants (diameter of 3.5 mm and length of 8 mm) were used in the mandible of each dog after observation of the surface morphology, as well as analysis of the composition of the surface elements by scanning electron microscopy-energy dispersive x-ray spectroscopy. At 4, 8, and 12 weeks after implantation, animals were euthanized to collect the mandibles so that we could perform the removal torque test to evaluate the implant stability in bone and histomorphometry to analyze the implant-bone osseointegration. RESULTS: Scanning electron microscopy results showed that uniformly distributed sponge-like structures were found on the SLA-treated surface and an apatite layer was observed on the SLA-SBF-treated surface (SLA-Bio group). In the energy dispersive x-ray spectroscopy analysis, the elements titanium, oxygen, carbon, calcium, and phosphorus were found on the surfaces of the SLA-Bio group, whereas titanium was the only element found in the other groups. The removal torque test showed that the peak removal torque values of the 3 groups increased gradually with the passage of time, and the peak removal torque values of the SLA-Bio group were significantly higher than those of the other groups (P < .01) at 4, 8, and 12 weeks after implantation. Histomorphometric analysis showed that osseointegration was being enabled more rapidly in the SLA-Bio group, as well as that the mineral apposition rate and percentage of bone-to-implant contact of the SLA-Bio group were higher than those of the remaining groups at 4, 8, and 12 weeks after implantation (P < .01). CONCLUSIONS: Treating titanium implants with SLA-SBF can improve osseointegration as well as increase the interfacial shear strength.

Thermal properties and crystallite morphology of nylon 66 modified with a novel biphenyl aromatic liquid crystalline epoxy resin.

In order to improve the thermal properties of important engineering plastics, a novel kind of liquid crystalline epoxy resin (LCER), 3,3',5,5' -Tetramethylbiphenyl-4,4' -diyl bis(4-(oxiran-2-ylmethoxy)benzoate) (M1) was introduced to blend with nylon 66 (M2) at high temperature. The effects of M1 on chemical modification and crystallite morphology of M2 were investigated by rheometry, thermo gravimetric analysis (TGA), dynamic differential scanning calorimetry (DSC) and polarized optical microscopy (POM). TGA results showed that the initial decomposition temperature of M2 increased by about 8 °C by adding 7% wt M1, indicating the improvement of thermal stability. DSC results illustrated that the melting point of composites decreased by 12 °C compared to M2 as the content of M1 increased, showing the improvement of processing property. POM measurements confirmed that dimension of nylon-66 spherulites and crystallization region decreased because of the addition of liquid crystalline epoxy M1.

Identification of ferroptosis-related proteins in ameloblastoma based on proteomics analysis.

PURPOSE: We used proteomic sequencing and experimental verification to identify the potential ferroptosis-related proteins in ameloblastoma. METHODS: Samples of ameloblastoma (n = 14) and normal gingival tissues (n = 5) were collected for proteomic sequencing to identify differentially expressed proteins (DEPs) in ameloblastoma. Ferroptosis-related genes were downloaded from FerrDb V2, which were then compared with DEPs to obtain ferroptosis-related DEPs (FR-DEPs). A functional enrichment analysis was performed, and a protein-protein interaction network was built. The hub proteins were screened using the Cytoscape software, and potential drugs targeting them were retrieved from the DrugBank database. A hub protein was selected for immunohistochemical validation, and its expression was assessed in ameloblastomas, odontogenic keratocysts, dentigerous cysts, and normal gingival tissues. The primary ameloblastoma cells were cultured to explore the effect of the protein on the migratory properties of the tumour cells. RESULTS: A total of 58 FR-DEPs were screened, and six hub proteins were identified: mTOR, NFE2L2, PRKCA, STAT3, EGFR, and CDH1. Immunohistochemical analysis showed that mTOR expression was upregulated in ameloblastomas compared with that in odontogenic keratocysts, dentigerous cysts, and normal gingival tissues. p-mTOR was highly expressed in ameloblastomas, with a positivity rate of 83.3%. In addition, rapamycin, an inhibitor of mTOR, can inhibit the migratory capacity of primary cultured ameloblastoma cells. CONCLUSION: Our results revealed the ferroptosis-related proteins in ameloblastomas and their underlying biological processes. Additionally, mTOR was overexpressed and was found to be associated with the aggressiveness of ameloblastomas, which may be a potential target for future treatments.

Determination of critical-sized defect of mandible in a rabbit model: Micro-computed tomography, and histological evaluation.

Objective: To evaluate a rabbit model of mandibular box-shaped defects created through an intraoral approach and determine the minimum size defect that would not spontaneously heal during the rabbit's natural life (or critical-sized defect, CSD). Methods: Forty-five 6-month-old rabbits were randomly divided into five defect size groups (nine each). Mandibular box-shaped defects of different sizes (4, 5, 6, 8, and 10 mm) were created in each hemimandible, with the same width and depth (3 and 2 mm, respectively). Four, 8, and 12 weeks post-surgery, three animals per group were euthanized. New bone formation was assessed using micro-computed tomography (MCT) and histomorphometric analyses. Results: Box-shaped defects were successfully created in the buccal region between the incisor area and the anterior part of the mental foramen in rabbit mandibles. Twelve weeks post-surgery, MCT analysis showed that the defects in the 4, 5, and 6 mm groups were filled with new bone, while those in the 8 and 10 mm groups remained underfilled. Quantitative analysis revealed that the bone mass recovery percentage in the 8 and 10 mm groups was significantly lower than that in the other groups (p < 0.05). There was no significant difference in the bone mass recovery percentage between the 8 and 10 mm groups (p > 0.05). Histomorphometric analysis indicated that the area of new bone formation in the 8 and 10 mm groups was significantly lower than that in the remaining groups (p < 0.05). There was no significant difference in the new bone area between the 8 and 10 mm groups (p > 0.05). Conclusions: The dimensions of box-shaped CSD created in the rabbit mandible through an intraoral approach were 8 mm × 3 mm × 2 mm. This model may provide a clinically relevant base for future tissue engineering efforts in the mandible.

Clinical observation of concentrated growth factor (CGF) combined with iliac cancellous bone and composite bone material graft on postoperative osteogenesis and inflammation in the repair of extensive mandibular defects.

PURPOSE: To evaluate the effects of concentrated growth factor (CGF), combined with a mixture of iliac cancellous and composite bone materials, on the repair of extensive mandibular defects. PATIENTS AND METHODS: This clinical trial involved patients with mandibular defects caused by large cystic lesions. The test group comprised 16 patients who underwent CGF combined with iliac cancellous bone and composite bone materials to repair extensive mandibular defects, whereas the control group comprised eight patients who underwent vascularised free fibula grafts for mandibular segmental defects. Postoperative exudatum was collected from patients on the 1st, 2nd, 3rd, and 4th days postoperatively, and osteogenic factor, including alkaline phosphatase (ALP), osteocalcin (BGP), and procollagen type I N-terminal propeptide (PINP), and inflammatory cytokines were performed. Additionally, regular cone beam computed tomography (CBCT) scans were conducted before and after surgery. RESULTS: On postoperative days 1-4, the expression levels of ALP, BGP, and PINP were higher in the test group, while those of IL-1α, IL-1ß, IL-6, IL-8, and TNF-α, which were identified as co-differentially expressing inflammatory cytokines, were all down-regulated in the exudatum of the test group. Regular CBCT radiological scans revealed a significant osteogenic effect in the test group. CONCLUSION: The use of CGF combined with iliac cancellous bone and composite bone materials to repair extensive mandibular jaw defects facilitates bone formation and reductions in inflammation in the defect area in the short term, which deserves further research in clinical practice.