Effect of acute normovolemic hemodilution on anesthetic effect, plasma concentration, and recovery quality in elderly patients undergoing spinal surgery.

OBJECTIVE: To explore the effect of acute normovolemic hemodilution (ANH) on the anesthetic effect, plasma concentration, and postoperative recovery quality in elderly patients undergoing spinal surgery. METHODS: A total of 60 cases of elderly patients aged 65 to 75 years who underwent elective multilevel spinal surgery were assigned randomly into the ANH group (n = 30) and control group (n = 30). Hemodynamic and blood gas analysis indexes were observed and recorded before ANH (T1), after ANH (T2), immediately after postoperative autologous blood transfusion (T3), 10 min (T4), 20 min (T5), 30 min (T6), 40 min (T7), and 50 min (T8) after the transfusion, and at the end of the transfusion (i.e., 60 min; T9). At T3 ~ 9, bispectral index (BIS) and train-of-four (TOF) stimulation were recorded and the plasma propofol/cisatracurium concentration was determined. The extubation time and recovery quality were recorded. RESULTS: The ANH group presented a lower MAP value and a higher SVV value at T2, and shorter extubation and orientation recovery time (P < 0.05) compared with the control group. BIS values at T8 and T9 were lower in the ANH group than those in the control group (P < 0.05). TOF values at T7 ~ 9 were lower in the ANH group than those in the control group (P < 0.05). There were no statistically significant differences in the postoperative plasma concentrations of propofol and cisatracurium between the groups (P > 0.05). CONCLUSION: During orthopedic surgery, the plasma concentration of elderly patients is increased after autologous blood transfusion of ANH, and the depth of anesthesia and muscle relaxant effect are strengthened, thus leading to delayed recovery of respiratory function and extubation.

White light emitting device based on single-phase CdS quantum dots.

White light emitting diodes (WLEDs) based on quantum dots (QDs) are emerging as robust candidates for white light sources, however they are suffering from the problem of energy loss resulting from the re-absorption and self-absorption among the employed QDs of different peak wavelengths. It still remains a challenging task to construct WLEDs based on single-phase QD emitters. Here, CdS QDs with short synthesis times are introduced to the fabrication of WLEDs. With a short synthesis time, on one hand, CdS QDs with a small diameter with blue emission can be obtained. On the other hand, surface reconstruction barely has time to occur, and the surface is likely defect-ridden, which enables the existence of a broad emission covering the range of green, yellow and red regions. This is essential for the white light emission of CdS QDs, and is very important for WLED applications. The temporal evolution of the PL spectra for CdS QDs was obtained to investigate the influence of growth time on the luminescent properties. The CdS QDs with a growth time of 0.5 min exhibited a colour rendering index (CRI) of 79.5 and a correlated colour temperature (CCT) of 6238 K. With increasing reaction time, the colour coordinates of the CdS QDs will move away from the white light region in the CIE 1931 chromaticity diagram. By integrating the as prepared white light emission CdS QDs with a violet GaN chip, WLEDs were fabricated. The fabricated WLEDs exhibited a CRI of 87.9 and a CCT of 4619 K, which satisfy the demand of general illumination. The luminous flux and the luminous efficiency of the fabricated WLEDs, being less advanced than current commercial white light sources, can be further improved, meaning there is a need for much more in-depth studies on white light emission CdS QDs.

Quantum dot white light emitting diodes with high scotopic/photopic ratios.

Alloy core/shell CdxZn1-xS/ZnS quantum dots (QDs) are emerging as robust candidates for light-emitting diodes (LEDs), however the emission range of the current CdxZn1-xS/ZnS is quite limited, ranging from 390 to 470 nm. It still remains a challenging task to construct white LEDs based on current CdxZn1-xS/ZnS system. Here, a versatile ZnSe with a moderate band gap is introduced onto the Cd0.1Zn0.9S core. The ZnSe shell, on one hand, can passivate the core surface which leads to bright emissions. On the other hand, it is essential in extending the emission to red region so that the emission wavelengths of Cd0.1Zn0.9S/ZnS and Cd0.1Zn0.9S/ZnSe QDs can cover the whole visible region, which is very important for white LED applications. Two- and four-hump QD-based LEDs are computationally and experimentally investigated. Results show that four-hump quantum dot light-emitting diodes (QLED) have better performances than the two-hump one, in the luminous and the vision properties. The fabricated white LEDs (WLEDs) based on Cd0.1Zn0.9S/ZnS and Cd0.1Zn0.9S/ZnSe QDs exhibits a scotopic/photopic ratio (S/P) ratio as high as 2.52, which exceeds the current limit of 2.50 by common lighting technologies, a color rendering index of 90.3, a luminous efficacy of optical radiation of 460.78 lumen per unit optical power, and a correlated color temperature of 5454 K. These results suggest that CdxZn1-xS/ZnS and CdxZn1-xS/ZnSe quantum dots serving as emitters hold great promise for the next-generation white light source with better S/P ratio.

Synthesis and spectroscopic properties of some novel BODIPY dyes.

BODIPY dyes have some unique properties including high fluorescence quantum yield, large extinction coefficiency, narrow absorption and emission band. However, most of BODIPY dyes display short emission wavelength and small Stokes shift, which limits their applications in biosensing and bioimaging in vivo. For bioimaging application, a fluorescent dye with long emission wavelength and large Stokes shift is highly desired. To push the absorption and emission spectrum of BODIPY to red and even far-red region, a COOEt group was introduced to the meso position, and some aromatic group was attached to the 3, 5 position of BODIPY core. The structure of resulting compounds were comfirmed by 1H NMR, 13C NMR and HR-MS. Dye-1 displays a strong UV-Vis absorption band centered at 536 nm and a sharp emission band is located at 592 nm, which is significantly red-shifted (80 nm) compared to ordinary BODIPY analogs. In addition, the meso-COOEt substituted BODIPYs exhibit high quantum yield and red to far-red emission. Notably surprisingly, the meso-COOEt substituted BODIPYs display almost separated UV-Vis absorption and emission spectra with a large Stokes shift (-60 nm). Time-dependent density functional theory calculations were conducted to understand the structure-optical properties relationship, and it was revealed that the large Stokes shift was resulted from the geometric change from the ground state to the first excited singlet state. The spectroscopic properties of these BODIPY dyes display very subtle solvent-dependence effect. Furthermore, BODIPY was tested for its ability of imaging in living cells. The results indicate that Dye-1 is a water-soluble and membrane-permeable probe. Therefore, these BODIPYs are a new family dyes with excellent spectroscopic properties and can be good candidates for bioimaging in living cells.

Exploration of the mechanism of reinfusion of fresh autologous blood in type 2 diabetes mice to induce macrophage polarization and inhibit erythrocyte damage.

AIMS/INTRODUCTION: Type 2 diabetes triggers an inflammatory response that can damage red blood cells. M2 macrophages have inhibitory effects on inflammation, and play an important role in tissue damage repair and fibrosis. Autologous blood transfusion has the potential to inhibit red blood cell damage by mediating macrophage polarization. MATERIALS AND METHODS: Swiss mice were used to establish a suitable type 2 diabetes model, and autologous blood transfusion was carried out. The mice were killed, the blood of the mice was collected and CD14+ monocytes were sorted. The expression levels of phenotypic molecules CD16, CD32 and CD206 in CD14+ monocytes were analyzed by flow cytometry. The proportion of M1 and M2 macrophages were analyzed by flow cytometry. The Q value, P50 , 2,3-diphosphoglycerate and Na+ -K+ -ATPase of red blood cells were detected. The red blood cell osmotic fragility test analyzed the red blood cell osmotic fragility. Western blot analysis was used to analyze the expression changes of erythrocyte surface membrane proteins or transporters erythrocyte membrane protein band 4.1, sphingosine-1-phosphate, glycolipid transfer protein and signal peptide peptidase-like 2A. RESULTS: Autologous blood transfusion induced a significant increase in the number of macrophages. The state and capacity of blood cells improved with autologous blood transfusion. Reinfusion of fresh autologous blood in type 2 diabetes mice made erythrocytes shrink. The expression of erythrocyte-related proteins proved that the erythrocyte injury in the reinfusion of fresh autologous blood + type 2 diabetes group was significantly reduced. CONCLUSION: The reinfusion of fresh autologous blood into the body of patients with type 2 diabetes can induce macrophage polarization to M2, thereby inhibiting red blood cell damage.

Regulation of Macrophage Polarization by miR-449a/Cripto-1-PI3K/AKT/NF-κB Signaling Pathway in Allogeneic Transfusion Mice.

In this study, the expression of Cripto-1 and the role of macrophage polarization in immune response after allogeneic transfusion were analyzed by constructing a mouse model of allogeneic transfusion. In order to analyze the effects of miR-449a on the PI3K/AKT/NF-κB signaling pathway and the expression of downstream related regulatory factors under normal and abnormal conditions, we adopt in vitro and in vivo experiments separately. The molecular mechanism of PI3K/AKT/NF-κB signaling pathway was analyzed by blocking or activating gene expression and western blotting. Experiment in vitro has confirmed that inhibition of miR-449a increased the protein expression of Cripto-1. In vivo experiments confirmed that allogeneic transfusion reduced the expression of Cripto-1, which further inhibited NF-κB signaling pathway through AKT/PI3K phosphorylation, regulated macrophage polarization, inhibited M1 polarization of macrophages, promoted M2 polarization, and thus affected immune response of the body.

Autologous blood transfusion impedes glycolysis in macrophages to inhibit red blood cell injury in type 2 diabetes through PI3K/Akt/PKM2 signaling axis.

AIMS: To explore the effect and mechanism of autologous blood transfusion impeding glycolysis in macrophages and inhibiting red blood cells (RBCs) injury in type 2 diabetes through PI3K/Akt/PKM2 signaling axis. METHODS: Cell transfection were performed and diabetic mice model was constructed. The group were divided into control (NC) and type 2 diabetes model (T2D). T2D model mice were injected with preserved autologous blood, si-PI3K, si-PKM2, si-NC Tran+T2D, (Tran+T2D+si-PI3K, Tran+T2D si-PKM2, Tran+T2D+si-NC) through tail vein. The anti-oxidative effects of transfusion of autologous blood in CD14+ monocytes were detected. The expression of PI3K/Akt/PKM2 protein in CD14+ monocytes were examined by western blot. Effect of autologous blood transfusion ameliorating RBCs injury by regulating PI3K and PKM2 in T2D mice were detected. RESULTS: Effects on oxidative stress in T2D mice were all overturned after autologous blood transfusion in T2D mice. The results manifested that the levels of PI3K, pAkt and PKM2 were downregulated, while the expression of HIF-1α was upregulated in CD14+ monocytes from T2D mice, whereas these influences were all effectively reversed by autologous blood transfusion in T2D mice. The survival rate of RBCs in the serum of T2D mice was declined in the serum of T2D mice, while the effect was reversed by the autologous blood transfusion. CONCLUSION: Autologous blood transfusion can reduce glycolysis in macrophages and inhibit the release of inflammatory factors through the PI3K/PKM2 signal axis, thereby inhibiting red blood cell damage and improving the oxygen-carrying capacity and survival activity of RBCs in diabetic patients.

Exploration of the effect of PUM1/Cripto-1 pathway on ferroptosis by regulating macrophage polarization in allogeneic blood transfused mice.

BACKGROUND: To study the link between macrophage polarization, PUM1/Cripto-1 pathway and ferroptosis in the allogeneic blood transfusion setting. METHODS: This is an exploratory research. The purpose of this study was to investigate the effect of PUM1/Cripto-1 pathway on ferroptosis by regulating macrophage polarization in allogeneic blood transfused mice. Establish in vitro cell models and in vivo rat models. To find out whether PUM1 and Cripto-1 were expressed, RT-qPCR and Western blot analyses were employed. The macrophage polarization markers iNOS, TNF-, IL-1, IL-6, Arg-1, and IL-10 were utilized to identify M1 and M2 macrophages. JC-1 staining was used to detect ATP membrane potential in peripheral blood macrophages. RESULTS: In animal experiments, expression of Cripto-1 was negatively regulated by PUM1 and promoted M1 type polarization of macrophages. Allogeneic blood transfusion assured good state of macrophage mitochondria. Allogeneic blood transfusion inhibited ferroptosis in macrophages by affecting the PUM1/Cripto-1 pathway. In cell experiments, PUM1 regulated Cripto-1 in mouse macrophage RAW264.7. Polarization of RAW264.7 cells was regulated by the PUM1/Cripto-1 pathway. The effect of PUM1/Cripto-1 pathway on macrophage ferroptosis in cell experiments was consistent with that in animal experiments. CONCLUSIONS: In this study, through in vivo cell experiments and in vitro animal experiments, it was successfully proved that PUM1/Cripto-1 pathway affected ferroptosis by regulating macrophage polarization in allogeneic blood transfused mice.

The use of sel-ligating appliance can reduce inflammatory response to orthodontic force and keep periodontal health in orthodontic treatment.

OBJECTIVE: Orthodontics, as a common way of orthodontic treatment, is usually to maintain oral health and protect periodontal tissue. The self-ligating appliance technique, since its advent in the 1930s, have been rather popular ammong the majority of orthodontists. This study was to determine that self-ligating appliance can reduce inflammation in gingival crevicular fluid (GCF) of patients receiving orthodontic treatment and keep periodontal health. METHODS: The clinical data of 97 orthodontic patients admitted to the Department of Stomatology of Fujian Provincial Hospital, Fujian Provincial Clinical College of Fujian Medical University from March 2019 to March 2020 were analyzed retrospectively. Among them, 42 patients receiving orthodontic treatment with traditional MBT straight-wire appliance (SWA) were included in the control group (CG) and 55 patients treated with self-ligating appliance were collected as the observation group (OG). The two cohorts were compared with respect to the following aspects: curative effect, pain degree on the 1st, 2nd, 3rd, 5th and 7th day after wearing the appliance, oral related quality of life (QoL) before and after orthodontic treatment, satisfaction with the orthodontic treatment, periodontal condition, and GCF and inflammatory factor contents before, 3 months and 6 months after orthodontic treatment. RESULTS: OG had significantly higher therapeutic efficacy of orthodontic treatment than CG (P<0.05). At the initial stage of treatment, the pain degree in OG was obviously lower than that in CG (P<0.05). Compared with CG, the plaque index (PLI), sulcus bleeding index (SBI), gingival recession (GR), periodontal probing depth (PPD) and clinical attachment loss (CAL) were better in OG after orthodontic treatment, and the differences were statistically significant (P<0.05). The contents of GCF, prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) in OG were lower than those in CG after orthodontic treatment, with significant differences between the two groups (P<0.05). Oral related QoL and orthodontic satisfaction were higher in OG, and the differences were statistically significant (P<0.05). CONCLUSIONS: Compared with traditional SWA, the self-ligating appliance in orthodontic treatment contributes to higher efficacy and satisfaction, less local inflammatory reaction, and significantly improved periodontal condition and oral health of patients.

An ICT-based fluorescence enhancement probe for detection of Sn2+ in cancer cells.

Development of a novel fluorescence enhancement probe for detection of Sn2+ in organisms, with high selectivity and sensitivity, is of great interest but remains a great challenge. Herein, an ICT-based fluorescence probe TPPB was rationally developed to act as an 'enhancement' luminescent and "naked-eye" indicator for Sn2+ detection. Importantly, spectroscopic studies indicated that TPPB was a fluorescence enhancement sensor for Sn2+ with rapid response, low detection limit (0.116 µM) and excellent binding constant (1.6 × 104 M-1). The mechanism of TPPB response to Sn2+ was further proved by 1H NMR titration, and enhancement calculations. Furthermore, TPPB is applied as a fluorescence probe for imaging in Hela cells, indicated that it can be potentially applied for Sn2+ sensing in biological fields.

A New Triangular Rotation and Advancement Pulp Flap for Lateral Oblique Fingertip Defect.

The fingertip is one of the most common sites of traumatic injuries faced by hand surgeons. In cases of lateral oblique amputation, only limited alternatives are available for reconstruction. This study introduced a new method involving rotation and use of an advancement pulp flap for covering lateral oblique defect and evaluated its outcome. METHOD: A series of 12 patients with 14 lateral oblique fingertip defects were recruited in this study. All fingertips were unreplantable and were injured distal to the proximal one-third of nail bed, with phalanx exposed. All cases received surgical reconstruction using a triangular rotation and advancement pulp flap. Static 2-point discrimination, cold intolerance, pain, hypersensitivity, range of motion, and aesthetic satisfaction were evaluated 6 months to 12 months postoperation. RESULT: Bone defect was noted in 7 cases. The area of defect was 10×7-20×12 mm2, and the angle of defect was 30-60 degrees. Mean follow-up was 14.3 months. No hook nail deformity, cold intolerance, and hypersensitivity were observed. One patient complained about pain postoperation, demanding a second operation. Static 2-point discrimination was between 5 and 8 mm in all cases. Range of motion of distal interphalangeal joint recovered to 20-45 degrees at the last follow-up. No stiffness was observed in the interphalangeal or metacarpophalangeal joints. All patients were satisfied with the appearance of the flap. CONCLUSION: The triangular rotation and advancement pulp flap is simple, safe, and reliable for treating lateral oblique defect of fingertip, providing scope for anatomical reconstruction and fair sensation and aesthetic recovery.

Repair of long segmental ulnar nerve defects in rats by several different kinds of nerve transposition.

Multiple regeneration of axonal buds has been shown to exist during the repair of peripheral nerve injury, which confirms a certain repair potential of the injured peripheral nerve. Therefore, a systematic nerve transposition repair technique has been proposed to treat severe peripheral nerve injury. During nerve transposition repair, the regenerated nerve fibers of motor neurons in the anterior horn of the spinal cord can effectively grow into the repaired distal nerve and target muscle tissues, which is conducive to the recovery of motor function. The aim of this study was to explore regeneration and nerve functional recovery after repairing a long-segment peripheral nerve defect by transposition of different donor nerves. A long-segment (2 mm) ulnar nerve defect in Sprague-Dawley rats was repaired by transposition of the musculocutaneous nerve, medial pectoral nerve, muscular branches of the radial nerve and anterior interosseous nerve (pronator quadratus muscle branch). In situ repair of the ulnar nerve was considered as a control. Three months later, wrist flexion function, nerve regeneration and innervation muscle recovery in rats were assessed using neuroelectrophysiological testing, osmic acid staining and hematoxylin-eosin staining, respectively. Our findings indicate that repair of a long-segment ulnar nerve defect with different donor nerve transpositions can reinnervate axonal function of motor neurons in the anterior horn of spinal cord and restore the function of affected limbs to a certain extent.

Repair of peripheral nerve defects by nerve transposition using small gap bio-sleeve suture with different inner diameters at both ends.

During peripheral nerve transposition repair, if the diameter difference between transposed nerves is large or multiple distal nerves must be repaired at the same time, traditional epineurial neurorrhaphy has the problem of high tension at the suture site, which may even lead to the failure of nerve suture. We investigated whether a small gap bio-sleeve suture with different inner diameters at both ends can be used to repair a 2-mm tibial nerve defect by proximal transposition of the common peroneal nerve in rats and compared the results with the repair seen after epineurial neurorrhaphy. Three months after surgery, neurological function, nerve regeneration, and recovery of nerve innervation muscle were assessed using the tibial nerve function index, neuroelectrophysiological testing, muscle biomechanics and wet weight measurement, osmic acid staining, and hematoxylin-eosin staining. There was no obvious inflammatory reaction and neuroma formation in the tibial nerve after repair by the small gap bio-sleeve suture with different inner diameters at both ends. The conduction velocity, muscle strength, wet muscle weight, cross-sectional area of muscle fibers, and the number of new myelinated nerve fibers in the bio-sleeve suture group were similar to those in the epineurial neurorrhaphy group. Our findings indicate that small gap bio-sleeve suture with different inner diameters at both ends can achieve surgical suture between nerves of different diameters and promote regeneration and functional recovery of injured peripheral nerves.

Reinnervation of spinal cord anterior horn cells after median nerve repair using transposition with other nerves.

Our previous studies have confirmed that during nerve transposition repair to injured peripheral nerves, the regenerated nerve fibers of motor neurons in the anterior horn of the spinal cord can effectively repair distal nerve and target muscle tissue and restore muscle motor function. To observe the effect of nerve regeneration and motor function recovery after several types of nerve transposition for median nerve defect (2 mm), 30 Sprague-Dawley rats were randomly divided into sham operation group, epineurial neurorrhaphy group, musculocutaneous nerve transposition group, medial pectoral nerve transposition group, and radial nerve muscular branch transposition group. Three months after nerve repair, the wrist flexion test was used to evaluate the recovery of wrist flexion after regeneration of median nerve in the affected limbs of rats. The number of myelinated nerve fibers, the thickness of myelin sheath, the diameter of axons and the cross-sectional area of axons in the proximal and distal segments of the repaired nerves were measured by osmic acid staining. The ratio of newly produced distal myelinated nerve fibers to the number of proximal myelinated nerve fibers was calculated. Wet weights of the flexor digitorum superficialis muscles were measured. Muscle fiber morphology was detected using hematoxylin-eosin staining. The cross-sectional area of muscle fibers was calculated to assess the recovery of muscles. Results showed that wrist flexion function was restored, and the nerve grew into the distal effector in all three nerve transposition groups and the epineurial neurorrhaphy group. There were differences in the number of myelinated nerve fibers in each group. The magnification of proximal to distal nerves was 1.80, 3.00, 2.50, and 3.12 in epineurial neurorrhaphy group, musculocutaneous nerve transposition group, medial pectoral nerve transposition group, and radial nerve muscular branch transposition group, respectively. Nevertheless, axon diameters of new nerve fibers, cross-sectional areas of axons, thicknesses of myelin sheath, wet weights of flexor digitorum superficialis muscle and cross-sectional areas of muscle fibers of all three groups of donor nerves from different anterior horn motor neurons after nerve transposition were similar to those in the epineurial neurorrhaphy group. Our findings indicate that donor nerve translocation from different anterior horn motor neurons can effectively repair the target organs innervated by the median nerve. The corresponding spinal anterior horn motor neurons obtain functional reinnervation and achieve some degree of motor function in the affected limbs.

Comparison of commonly used retrograde tracers in rat spinal motor neurons.

The purpose of this study was to investigate the effect of four fluorescent dyes, True Blue (TB), Fluoro-Gold (FG), Fluoro-Ruby (FR), and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI), in retrograde tracing of rat spinal motor neurons. We transected the muscle branch of the rat femoral nerve and applied each tracer to the proximal stump in single labeling experiments, or combinations of tracers (FG-DiI and TB-DiI) in double labeling experiments. In the single labeling experiments, significantly fewer labeled motor neurons were observed after FR labeling than after TB, FG, or DiI, 3 days after tracer application. By 1 week, there were no significant differences in the number of labeled neurons between the four groups. In the double-labeling experiment, the number of double-labeled neurons in the FG-DiI group was not significantly different from that in the TB-DiI group 1 week after tracer application. Our findings indicate that TB, FG, and DiI have similar labeling efficacies in the retrograde labeling of spinal motor neurons in the rat femoral nerve when used alone. Furthermore, combinations of DiI and TB or FG are similarly effective. Therefore, of the dyes studied, TB, FG and DiI, and combinations of DiI with TB or FG, are the most suitable for retrograde labeling studies of motor neurons in the rat femoral nerve.

Large animal models of human cauda equina injury and repair: evaluation of a novel goat model.

Previous animal studies of cauda equina injury have primarily used rat models, which display significant differences from humans. Furthermore, most studies have focused on electrophysiological examination. To better mimic the outcome after surgical repair of cauda equina injury, a novel animal model was established in the goat. Electrophysiological, histological and magnetic resonance imaging methods were used to evaluate the morphological and functional outcome after cauda equina injury and end-to-end suture. Our results demonstrate successful establishment of the goat experimental model of cauda equina injury. This novel model can provide detailed information on the nerve regenerative process following surgical repair of cauda equina injury.

[Three-dimensional finite element analysis on the effect of posterior cross-bite of individual teeth on temporomandibular joint].

OBJECTIVE: To analyze the stress distribution of temporomandibular joint (TMJ) in posterior cross-bite of individual teeth and in normal occlusion during the intercuspal occlusion (ICO). METHODS: On the basis of the geometric TMJ model of normal occlusion, the TMJ finite element model of posterior cross-bite of individual teeth was reconstructed. The occlusal force and boundary conditions were applied on the model. Using three-dimensional finite element method (FEM), the stress distribution of TMJ in posterior cross-bite of individual teeth was analyzed by simulating the ICO load. RESULTS: No significant differences were found in stress distribution in various TMJ structures between posterior cross-bite of individual teeth and normal occlusion. However, the stress level was higher and the stress distribution was more inhomogeneous in posterior cross-bite of individual teeth than in normal occlusion. In the cross-bite malocclusion of individual posterior teeth, the maximum of von Mises stress was 0.792 MPa, the maximum principal stress was 0.598 MPa and the minimum principal stress was -0.744 MPa. But in normal occlusion, the maximum of von Mises stress was 0.592 MPa, the maximum principal stress was 0.395 MPa and the minimum principal stress was -0.554 MPa. CONCLUSIONS: When the ICO load was applied, the stress distribution of TMJ was more inhomogeneous and the stress level was higher in posterior cross-bite of individual teeth than in normal occlusion.

[Three-dimensional reconstruction of temporomandibular joint with CT and MRI medical image fusion technology].

OBJECTIVE: To investigate the method of the three-dimensional reconstruction of temporomandibular joint (TMJ) on the basis of CT and MRI medical image fusion technology, which establishes good foundation for a series biomechanical studies and clinical analysis. METHODS: The geometric data for the TMJ model were obtained from a young and healthy male volunteer. Twelve spherical markers were located on the regions of both TMJ and mental tubercles, where CT and MRI scans can reach. The three-dimensional geometric of the hard and soft tissues of TMJ was reconstructed by CT and MRI scans data, which was based on the registration procedures of spherical markers located on the face of the volunteer. RESULTS: The three-dimensional geometric model of TMJ was obtained, including hibateral articular disc, mandible, glenoid fossa and inferior teeth, and it had better geometric similarity. The results showed that the methods of three-dimensional reconstruction of TMJ with CT and MRI medical image fusion technology can be operated easily and promptly. The constructed model had good morphology. CONCLUSION: It is feasible to construct the three-dimensional model of TMJ on the basis of the registration procedures of spherical markers and CT-MRI medical image fusion technology. It has the advantage of simulating both hard and soft tissues reasonably. The model well expresses the shape of the TMJ.