Streamlining complex mandibular fracture treatment: Integration of virtual surgical planning and short-segment drilling guides.

This study aimed to evaluate the feasibility and accuracy of a combined virtual surgical planning (VPS) and short-segment drilling guides (SSDGs) workflow for the treatment of complex mandibular fractures. Consecutive patients with complex mandibular fractures underwent treatment using the VPS and SSDGs workflow from August 2020 to April 2022. Various mandibular landmarks were compared between the preoperative virtual surgical plan and postoperative data, including condylar distance (CoD), mandibular angle width (GoL-GoR), GoMeGo angle (∠GoL-Me-GoR), the difference in mandibular angles between the left and right sides (Δ∠Co-Go-Me), and the difference in length between the left and right mandibular body (ΔGo-Me). Additionally, preoperative preparation time and surgical duration were retrospectively analyzed and compared to conventional surgery. All 14 consecutive patients with complex mandibular fractures achieved successful reduction using the VPS and SSDGs workflow. Three-dimensional comparison revealed a mean deviation distance of 0.91 ± 0.50 mm and a root-mean-square deviation of 1.75 ± 0.47 mm between the preoperative designed mandible model and the postoperative mandible model. The percentage of points with deviation distances less than 2 mm, 1 mm, and 0.5 mm between preoperative and postoperative models were 78.47 ± 8.87 %, 60.02 ± 14.28 %, and 38.64 ± 15.48 %, respectively. There were no significant differences observed in CoD, GoL-GoR, ∠GoL-Me-GoR, Δ∠Co-Go-Me, and ΔGo-Me between preoperative virtual surgical planning and postoperative measurements. Furthermore, no significant differences were found in the injury-to-surgery interval, admission-to-surgery interval, and surgical duration between the workflow and conventional surgery. The combined VPS and SSDGs workflow proved to be an accurate and feasible method for treating complex mandibular fractures. It offers advantages such as minimal preoperative preparation time and the ability to precise transfer screw positions of the pre-bent reconstruction plate during surgery. This approach is particularly suitable for managing complex mandibular fractures.

Roles of Pyroptosis-Related Genes in the Diagnosis and Subtype Classification of Periodontitis.

Pyroptosis is widely involved in many diseases, including periodontitis. Nonetheless, the functions of pyroptosis-related genes (PRGs) in periodontitis are still not fully elucidated. Therefore, we aimed to investigate the role of PRGs in periodontitis. Three datasets (GSE10334, GSE16134, and GSE173078) from the Gene Expression Omnibus (GEO) were selected to analyze the differences in expression values of the PRGs between nonperiodontitis and periodontitis tissue samples using difference analysis. Following this, five hub PRGs (charged multivesicular body protein 2B, granzyme B, Z-DNA-binding protein 1, interleukin-1ß, and interferon regulatory factor 1) predicting periodontitis susceptibility were screened by establishing a random forest model, and a predictive nomogram model was constructed on the basis of these genes. Decision curve analysis suggested that the PRG-based predictive nomogram model could provide clinical benefits to patients. Three distinct PRG patterns (cluster A, cluster B, and cluster C) in the periodontitis samples were revealed according to the 48 significant PRGs, and the difference in the immune cell infiltration among the three patterns was explored. We observed that all infiltrating immune cells, except type 2 T helper cells, differ significantly among the three patterns. To quantify the PRG patterns, the PRG score was calculated by principal component analysis. According to the results, cluster B had the highest PRG score, followed by cluster A and cluster C. In conclusion, PRGs significantly contribute to the development of periodontitis. Our study of PRG patterns might open up a new avenue to guide individualized treatment plans for patients with periodontitis.

Chk2 deletion rescues Bmi1 deficiency-induced mandibular osteoporosis by blocking DNA damage response pathway.

OBJECTIVES: Bmi1 deficiency has been proved to be able to cause mandibular osteoporosis through suppressing oxidative stress. However, the role of DNA damage response pathway in this pathogenesis had not been well understood. In this study, we investigate whether mandibular osteoporosis induced by Bmi1 deficiency could be rescued by blocked DNA damage response pathway. METHODS: The protein expression levels of antioxidant enzymes and DNA damage and damage response pathway molecules in mandibular tissue were examined using Western blots. Double knockout mice that lacked both Bmi1 and Chk2 were generated and their mandibular phenotypes were compared at 6 weeks old to wild-type, Chk2-/-, and Bmi1-/- mice using radiograph, micro-CT, histopathology, cellular and molecular techniques. RESULTS: Bmi1 deficiency induces oxidative stress and DNA damage and activates DNA damage response pathways in mouse mandibles. Chk2 deletion rescued mandibular osteoporosis through promoting formation of osteoblastic bone as well as decreasing osteoclastic bone resorption. Mechanistically, Chk2 deletion suppressed oxidative stress, DNA damage, as well as cell senescence. In addition, it boosted proliferation of bone marrow mesenchymal stem cells (BM-MSCs) that derived from mandible through blocking the DNA damage response pathway. CONCLUSION: Abolish the expression of Chk2 could rescue Bmi1 deficiency-related mandibular osteoporosis through promoting BM-MSC proliferation and osteoblastic bone formation, reducing osteoclastic bone resorption, decreasing oxidative stress, inhibiting damage of DNA and associated response pathways, suppressing cell senescence as well as senescence-associated secretory phenotype (SASP). These findings offer a theoretical basis for using Chk2 or p53 inhibitors to prevent and treat age-related mandibular osteoporosis.

Short-Segment Drilling Guides for the Management Comminuted Mandibular Fractures.

ABSTRACT: Treatment of a severely comminuted mandibular fracture is challenging. This technical note describes a novel office-based workflow, combining virtual surgery planning with short-segment drilling guides. The authors reduced the comminuted mandibular fractures via virtual surgery planning. Then, the reconstructed mandible model was printed using an in-house 3D printer. Next, the reconstruction plate was preformed according to the shape of the mandibular model surface, and the position of the screw hole in the mandibular surface was determined. Finally, hand-made short-segment drilling guides for screw position transfer were fabricated with temporary resin. During the operation, the authors reset the guides for the drill to make screw holes as planned. After the hole was drilled, the pre-bent plate was applied to the mandible. The fracture was expected to be reduced, when tightening the screws. in our workflow, by using short and simple operative procedures, the authors were able to achieve precise reduction and reduce the operation time.

Influence of post-label delay time on the performance of 3D pseudo-continuous arterial spin labeling magnetic resonance imaging in the characterization of parotid gland tumors.

OBJECTIVE: To evaluate the influence of post-label delay times (PLDs) on the performance of 3D pseudo-continuous arterial spin labeling (pCASL) magnetic resonance imaging for characterizing parotid gland tumors and to explore the optimal PLDs for the differential diagnosis. MATERIALS AND METHOD: Fifty-eight consecutive patients with parotid gland tumors were enrolled, including 33 patients with pleomorphic adenomas (PAs), 16 patients with Warthin's tumors (WTs), and 9 patients with malignant tumors (MTs). 3D pCASL was scanned for each patient five times, with PLDs of 1025 ms, 1525 ms, 2025 ms, 2525 ms, and 3025 ms. Tumor blood flow (TBF) was calculated, and compared among different PLDs and tumor groups. Performance of TBF at different PLDs was evaluated using receiver operating characteristic analysis. RESULTS: With an increasing PLD, TBF tended to gradually increase in PAs (p < 0.001), while TBF tended to slightly increase and then gradually decrease in WTs (p = 0.001), and PAs showed significantly lower TBF than WTs at all 5 PLDs (p < 0.05). PAs showed significantly lower TBF than MTs at 4 PLDs (p < 0.05), except at 3025 ms (p = 0.062). WTs showed higher TBF than MTs at all 5 PLDs; however, differences did not reach significance (p > 0.05). Setting a TBF of 64.350 mL/100g/min at a PLD of 1525 ms, or a TBF of 23.700 mL/100g/min at a PLD of 1025 ms as the cutoff values, optimal performance could be obtained for differentiating PAs from WTs (AUC = 0.905) or from MTs (AUC = 0.872). CONCLUSIONS: Short PLDs (1025 ms or 1525 ms) are suggested to be used in 3D pCASL for characterizing parotid gland tumors in clinical practice. KEY POINTS: • With 5 different PLDs, 3D pCASL can reflect the variation of blood flow in parotid gland tumors. • 3D pCASL is useful for characterizing PAs from WTs or MTs. • Short PLDs (1025 ms or 1525 ms) are suggested to be used in 3D pCASL for characterizing parotid gland tumors in clinical practice.

Salivary Microbiome Variation in Early Childhood Caries of Children 3-6 Years of Age and Its Association With Iron Deficiency Anemia and Extrinsic Black Stain.

ECC is a common clinical manifestation of the oral cavity in childhood and Iron deficiency-anemia (IDA) is a high-risk factor but extrinsic black stain on the tooth surface is a protective factor for caries. There is limited information about oral microecological change in early children who suffer from ECC with IDA and extrinsic black stain (BS). This study enrolled 136 children aged 3-6 years. Dental caries and teeth BS were examined. Saliva was collected for 16S rRNA gene and fingertip blood were for Hemoglobin test. There are 93 ECC including 13 with IDA (IDA ECC) and 80 without IDA (NIDA ECC) and 43 caries free (CF) including 17 with BS (BSCF) and 26 without BS (NBS CF). Statistical analysis of microbiota data showed differences of the oral flora in different groups. The oral flora of the IDA ECC group had a high diversity, while the BSCF group had a low diversity. The bacterial genera Bacillus, Moraxella, and Rhodococcus were enriched in the IDA ECC while Neisseria was enriched in the NIDA ECC. Neisseria only exhibited high abundance in the BSCF, and the remaining genera exhibited high abundance in the NBSCF. Interestingly, the BSCF had the same trend as the NIDA ECC, and the opposite trend was observed with IDA ECC. We established random forest classifier using these biomarkers to predict disease outcomes. The random forest classifier achieved the best accuracy in predicting the outcome of caries, anemia and black stain using seven, one and eight biomarkers, respectively; and the accuracies of the classifiers were 93.35%, 94.62% and 95.23%, respectively. Our selected biomarkers can achieve good prediction, suggesting their potential clinical implications.

Micro/nanostructured calcium phytate coating on titanium fabricated by chemical conversion deposition for biomedical application.

A bioactive micro/nanostructured calcium phytate coating was successfully prepared on titanium surfaces by chemical conversion deposition, mainly through hydrothermal treatment of a mixed solution of phytic acid and saturated calcium hydroxide solution. Ultraviolet radiation was carried out to improve the adhesion of the coating to the titanium substrate. Pure titanium with a sandblasted/acid-etched surface was used as the control group. The topography and chemical composition of the modified surfaces were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and static water contact angle measurement. A pull-off test was performed to measure the coating-to-substrate adhesion strength. Bovine serum albumin was used as a model to study the protein adsorption effect. Cells were cultured on titanium surfaces for 7 days in osteogenic differentiation medium, then the osteoblast compatibility in vitro were explored by alkaline phosphatase and alizarin red staining. After 1, 2, 4 and 8 wks of immediate implantation of titanium implants into the mandibles of New Zealand white rabbits, biological effects in vivo were researched by microcomputed tomography analysis and histological evaluation. The results indicated that the roughness and hydrophilicity of the modified surfaces with micro/nanostructure remarkably increased compared to those of the control group. The pull-off test showed the average adhesion strength at the coating-substrate interface to be higher than 13.56 ± 1.71 MPa. In addition, approximately 4.41 mg/L calcium ion was released from the calcium phytate micro/nano coatings to the local environment after 48 h of immersion. More importantly, the micro/nanostructure titanium substrates significantly promoted cellular differentiation in vitro and in vivo. After 8 wks, the bone implant contact ratio (BIC, %) of the modified implants was higher than that of the control group, at 94.09 ± 0.55% and 86.18 ± 1.99% (p < 0.05). Overall, this study provided new insights into the factors promoting early osseointegration of titanium alloys, which had great potential not only for dental implants but also for various other biomaterial applications.

Differentiation of salivary gland tumor using diffusion-weighted imaging with a fractional order calculus model.

OBJECTIVE: To evaluate the feasibility of using imaging parameters (D, ß and µ) obtained from fractional order calculus (FROC) diffusion model to differentiate salivary gland tumors. METHODS: 15 b-value (0-2000 s/mm2) diffusion-weighted imaging (DWI) was scanned in 62 patients with salivary gland tumors (47 benign and 15 malignant). Diffusion coefficient D, fractional order parameter ß (which correlates with tissue heterogeneity) and a microstructural quantity µ of the solid portion within the tumor were calculated, and compared between benign and malignant groups, or among pleomorphic adenoma (PA), Warthin's tumor (WT), and malignant tumor (MT) groups. Performance of FROC parameters for differentiation was assessed using receiver operating characteristic analysis. RESULTS: None of the FROC parameters exhibited significant differences between benign and malignant group (D, p = 0.150; ß, p = 0.967; µ, p = 0.693). WT showed significantly lower D (p < 0.001) and ß (p < 0.001), while higher µ (p = 0.001) than PA. Combination of D, ß and µ showed optimal diagnostic performance (area under the curve, AUC, 0.998). MT showed significantly lower D (p = 0.001) and ß (p = 0.025) than PA, while no significant difference was found on µ (p = 0.064). Combination of D and ß showed optimal diagnostic performance (AUC, 0.933). Significant difference was found on ß (p = 0.027) between MT and WT, while not on D (p = 0.806) and µ (p = 0.789). Setting a ßof 0.615 as the cut-off value, optimal diagnostic performance could be obtained (AUC = 0.806). CONCLUSION: A non-Gaussian FROC diffusion model can serve as a noninvasive and quantitative imaging technique for differentiating salivary gland tumors. ADVANCES IN KNOWLEDGE: (1) PA showed higher D and ß and lower µ than WT. (2) PA had higher D and ß than MT. (3) WT demonstrated lower ß than MT. (4) ß, as a new FROC parameter, could offer an added value to the differentiation.

Let-7d modulates the proliferation, migration, tubulogenesis of endothelial cells.

Endothelial cells are important components of peripheral nerve stumps that contribute to Schwann cell migration and peripheral nerve regeneration. Let-7d modulates the phenotype of Schwann cells and affected peripheral nerve regeneration. However, the regulatory roles of let-7d on endothelial cells remain undetermined. In this study, by transfecting cultured human umbilical vein endothelial cells (HUVECs) with let-7d mimic or let-7d inhibitor, we investigated the biological effects of let-7d on endothelial cells. EdU proliferation assay showed that upregulated let-7d decreased the proliferation rates of HUVECs while downregulated let-7d increased the proliferation rates of HUVECs. Transwell-based migration assay and wound-healing assay demonstrated that let-7d inhibited the migration ability of HUVECs. Matrigel assay suggested that let-7d decreased the numbers of formed meshes and suppressed the tubulogenesis of HUVECs. RNA sequencing, bioinformatic analysis, gene expression validation, and luciferase assay suggested that let-7d directly targeted interferon-induced protein 44 like (IFI44L) gene and negatively regulated the expression of IFI44L. Taken together, our study illuminated the inhibitory roles of let-7d on the proliferation, migration, and tubulogenesis of endothelial cells, identified the target gene of let-7d, and deepened the understanding of the biological effects of let-7d on key elements of peripheral nerve regeneration.

Histogram analysis of apparent diffusion coefficient maps for differentiating malignant from benign parotid gland tumors.

PURPOSE: To evaluate the diagnostic performance of histogram parameters derived from diffusion-weighted imaging (DWI) for differentiating malignant from benign parotid gland tumors compared with that of hotspot region of interest (ROI)-based apparent diffusion coefficient (ADC) measurement. METHODS: Our study retrospectively enrolled 60 patients with parotid gland tumors who had undergone DWI scan for pre-treatment evaluation. ADC measurements were performed using hotspot ROI (ADCHS-ROI)-based and histogram-based approach. Histogram parameters included mean (ADCmean), median (ADCmedian), 10th (ADC10), 90th (ADC90) percentiles, skewness and kurtosis of ADC. Mann-Whitney U test, Kruskal-Wallis test with post hoc Dunn-Bonferroni method and receiver operating characteristic (ROC) curve analyses were used for statistical analyses. RESULTS: ADCHS-ROI and ADC histogram parameters showed no significant differences between malignant and benign parotid gland tumors (All Ps > 0.05). Within the sub-group analyses, Warthin's tumors showed the lowest ADCHS-ROI, ADCmean, ADCmedian, ADC10 and ADC90 value, followed by malignant tumors and pleomorphic adenomas (All Ps < 0.05). ADC10 out-performed ADCHS-ROI in differentiating malignant tumors from pleomorphic adenomas (area under curve, 0.890 vs 0.821; sensitivity, 79.31 vs 82.76%; specificity, 90.91 vs 72.73%; P = 0.016), and improved the diagnostic performance in differentiating malignant tumors from Warthin's tumors (area under curve, 1.000 vs 0.965; sensitivity, 100.00 vs 90.91%), although the difference was not significant (P = 0.348). CONCLUSIONS: ADC histogram analysis, especially ADC10, might be a promising imaging biomarker for characterizing parotid gland tumors.

Endoscopic mucosal autograft for treating esophageal caustic strictures: preliminary human experience.

BACKGROUND: Esophageal caustic stricture is a stubborn disease and postoperative restenosis limits the clinical efficacy of endoscopic dilation. Autologous mucosal grafts have been successfully applied in the treatment of urethral stricture and in the prevention of stricture after extensive mucosal resection. We aimed to use mucosal autografting performed endoscopically to treat refractory esophageal stricture. METHODS : Three patients with intractable corrosive esophageal stricture were treated endoscopically by combining dilation with autologous mucosal transplantation. RESULTS : All procedures were successful with no severe complications. Mucosal regeneration was shown at the transplanted segments. One patient was able to maintain a normal diet with complete remission after 1 year of follow-up. Intraluminal stenosis and dysphagia were significantly improved in another two patients. CONCLUSIONS : Mucosal autografting can achieve esophageal re-epithelialization, inhibit undesired fibrosis, prevent restenosis, and promote functional regeneration.

Gelatin-methacrylamide gel loaded with microspheres to deliver GDNF in bilayer collagen conduit promoting sciatic nerve growth.

In this study, we fabricated glial cell-line derived neurotrophic factor (GDNF)-loaded microspheres, then seeded the microspheres in gelatin-methacrylamide hydrogel, which was finally integrated with the commercial bilayer collagen membrane (Bio-Gide(®)). The novel composite of nerve conduit was employed to bridge a 10 mm long sciatic nerve defect in a rat. GDNF-loaded gelatin microspheres had a smooth surface with an average diameter of 3.9±1.8 µm. Scanning electron microscopy showed that microspheres were uniformly distributed in both the GelMA gel and the layered structure. Using enzyme-linked immunosorbent assay, in vitro release studies (pH 7.4) of GDNF from microspheres exhibited an initial burst release during the first 3 days (18.0%±1.3%), and then, a prolonged-release profile extended to 32 days. However, in an acidic condition (pH 2.5), the initial release percentage of GDNF was up to 91.2%±0.9% within 4 hours and the cumulative release percentage of GDNF was 99.2%±0.2% at 48 hours. Then the composite conduct was implanted in a 10 mm critical defect gap of sciatic nerve in a rat. We found that the nerve was regenerated in both conduit and autograft (AG) groups. A combination of electrophysiological assessment and histomorphometry analysis of regenerated nerves showed that axonal regeneration and functional recovery in collagen tube filled with GDNF-loaded microspheres (GM + CT) group were similar to AG group (P>0.05). Most myelinated nerves were matured and arranged densely with a uniform structure of myelin in a neat pattern along the long axis in the AG and GM + CT groups, however, regenerated nerve was absent in the BLANK group, left the 10 mm gap empty after resection, and the nerve fiber exhibited a disordered arrangement in the collagen tube group. These results indicated that the hybrid system of bilayer collagen conduit and GDNF-loaded gelatin microspheres combined with gelatin-methacrylamide hydrogels could serve as a new biodegradable artificial nerve guide for nerve tissue engineering.

Polydopamine-coated paper-stack nanofibrous membranes enhancing adipose stem cells' adhesion and osteogenic differentiation.

In the fabrication of 3-D complex tissues for implantation, layer-by-layer (LBL) electrospun nanofibrous scaffolds have recently received intensive interest. However, poor cell adhesion and cell expansion between the layers in an LBL stack remain important issues. In this study, we report a mussel-inspired, biomimetic approach to functionalize the surface of PCL/gelatin nanofibrous membranes coated with poly (dopamine) (PDA). Our study demonstrates that a PDA coating on electrospun PCL/gelatin nanofibers leads to a significant change in their surface properties and a higher adhesion force. Furthermore, we found that PDA coating promotes the adhesion and growth of adipose stem cells (ADSCs). In 3-D LBL stacked scaffolds, more cells survived in a PAD-coated scaffold than in a non-coated one. The PDA coating was further demonstrated to promote the osteogenic differentiation of ADSCs in LBL paper-stacking membranes. Our study suggests that PDA-coated paper-stacking nanofiber membranes present a facile and economic method for the development of 3D tissue engineering.

Rapid identification of anterior and posterior root of cauda equina nerves by near-infrared diffuse reflectance spectroscopy.

A new rapid chemometric method has been developed to identify the anterior and posterior roots of cauda equina nerves by near-infrared (NIR) diffuse reflectance spectroscopy. NIR spectra of nerves were measured using a Fourier transform NIR spectrometer equipped with a fiber-optic probe. The result revealed no observable difference in the spectra between the anterior and posterior root samples, but the two roots could be identified by cluster analysis based on the differences of their spectral features. The overall accuracy of the cluster analysis model was 87.5%, and the accuracy for the actual anterior root and actual posterior root were 95% and 80%, respectively. The result suggested that NIR spectroscopy in combination with the chemometrics method (cluster analysis) could be used to classify the anterior and posterior roots of cauda equina nerves. The proposed method required only a few minutes, while classical methods commonly required at least one hour. It was demonstrated that the new method could provide a rapid, correct, nondestructive and low-cost potential means to quickly differentiate anterior and posterior roots in mixed cauda equina nerves, which would be helpful for surgeons to align nerve stumps correctly.

Superolateral dislocation of the intact mandibular condyle into the temporal fossa: review of the literature and report of a case.

Anterior dislocation of the mandibular condyle is common, but superolateral dislocation is quite rare. Because of its rarity, this type of dislocation is often misdiagnosed or completely overlooked. We describe an additional case of superolateral dislocation of the intact condyle into the temporal fossa. We review all of the available English literature on superolateral dislocation and discuss a causative mechanism, the diagnostic features, and clinical management.