Objective To explore the effects of multiple intravenous tranexamic acid (Ⅳ-TXA) administrations after total knee arthroplasty (TKA) on fibrinolytic activity and inflammatory response in an enhanced recovery after surgery (ERAS) program and to assess the efficacy and safety of Ⅳ-TXA.Methods One hundred and forty-one severe knee osteoarthritis patients following primary unilateral TKA from January 2016 to April 2017 were investigated retrospectively.The patients were divided into following three groups based on the dosage of Ⅳ-TXA after surgery:40 patients received ≤3 g Ⅳ-TXA after surgery (group T1),50 patients received 4 g (group T2) and the other 51 patients received ≥5 g Ⅳ-TXA (group T3).The total blood loss (TBL),hidden blood loss (HBL),transfusion rate,maximum hemoglobin (Hb) drop,the incidence of intramuscular venous thrombosis,deep vein thrombosis (DVT) and pulmonary embolism (PE),fibrinolysis parameters [fibrin(-ogeu) degradation products (FDP),D-dimer],and inflammation markers [C-reactive protein (CRP),interleukin-6 (IL-6)] during perioperative period were evaluated.In addition,correlation analyses between the dosage of Ⅳ-TXA and fibrinolysis parameters and inflammation markers were conducted.Results The mean TBL,HBL and maximum Hb drop in group T2 (537.16±270.43 ml,431.36±271.99 ml,19.68± 10.68 g/L) and T3 (541.31±290.00 ml,439.94±290.71 ml,20.24±8.48 g/L) were lower than those in group T1 (748.22±394.34 ml,P=0.012,0.013;636.47±388.14 ml,P=0.011,0.015;25.88± 11.77 g/L,P=0.005,0.010,respectively).No patient needed transfusion in all groups.There was no statistically difference in the incidence of intramuscular venous thrombosis of lower limbs among three groups (P＞ 0.05).No episode of DVT or PE occurred in any group in two weeks after surgery.There were negative correlation between the dosage of Ⅳ-TXA and FDP at postoperative day 1 and day 3 (r=-0.191,P=0.025;r=-0.291,P=0.001) and D-dimer on postoperative day 3 (r=-0.176,P=0.048).Moreover,the CRP (r=-0.184,P=0.036) and IL-6 (r=-0.269,P=0.002) level in serum on postoperatire day 1 also showed a negative relationship with the dosage of Ⅳ-TXA after surgery.Conclusion The multiple Ⅳ-TXA (≥4 g) after surgery can further reduce the TBL,HBL and maximum Hb drop following primary TKA in ERAS program without increasing the risk of thrombotic events.Most importantly,the effect of anti-fibrinolysis will be enhanced and may have an anti-inflammatory effect with the dosage of Ⅳ-TXA increased.

Objective: To investigate the inhibitory effect of polydopamine (PDA) on enamel demineralization in isolated teeth and the induction of hydroxyapatite (HA) production on the surface of demineralized enamel to provide a novel protocol for the prevention and treatment of enamel demineralization. Methods: Twenty isolated bovine teeth were cut into 20 enamel slices and randomly divided into an experimental group and a control group, with 10 slices in each group. The enamel slices in the experimental group were immersed in 2 mg/mL freshly prepared dopamine solution and incubated for 24 hours at room temperature in the dark to prepare the PDA coating, while the control group was left untreated. Then, the isolated bovine teeth, with and without PDA coating, were immersed in artificial demineralization solution at 37 °C for 3 days, followed by 7 days in simulated body fluid (SBF), and the immersion solution was changed daily. The surface morphology of enamel was observed by scanning electron microscopy (SEM), the calcium/phosphorus ratio of the enamel surface was analyzed by energy dispersive spectroscopy (EDS), and the characteristic functional groups in enamel deposits were analyzed by Fourier transform infrared spectroscopy (FTIR). Results: Compared with the control group, the number of demineralized pores produced after 3 d of enamel demineralization with polydopamine coating was less, and the diameter was smaller. EDS elemental analysis showed that the Ca/P ratio after enamel demineralization was 2.37 in the experimental group, which was smaller than the 2.53 ratio in the control group. In the remineralization experiment, after 7 days of remineralization of PDA coated enamel in the experimental group, lamellar grains were produced on the enamel surface, and the growth showed obvious directionality, growth regularity and uniform arrangement. In the control group, the surface of enamel was flocculent mineral deposit, and the crystallinity was poor. The FTIR results proved that the enamel surface deposit of PDA-coated enamel was HA after 7 d of remineralization. Conclusion PDA can affect the nucleation process of HA and promote the production of HA on the surface of demineralized enamel.

BACKGROUND:Lingual movable wing is a new type of lingual orthodontic technique and the different stretching lengths of the wring affect the torque control effect of anterior teeth.However,there is yet no related biomechanical research. OBJECTIVE:To investigate the displacement trend of dentition during adduction of mandibular anterior teeth and the effect of different wing stretching lengths on the biomechanical effect of mandibular anterior teeth. METHODS:The data of the mandible and lower dentition were collected by cone-beam CT and reconstructed using Mimics software to establish a three-dimensional finite element model of mandibular anterior teeth adducted by the lingual movable wing.The ANSYS software was used to analyze the initial displacement of the mandibular anterior teeth under the following conditions:A,2 mm stretching length;B,2.5 mm stretching length;C,3 mm stretching length;and D,3.5 mm stretching length. RESULTS AND CONCLUSION:The trend of initial displacement of lower dentition:The central incisors moved lingually with depression,the lateral incisors and canines moved mildly lingually with mesial lingual torsion,the second premolar was tilted distally with a marked lingual inclination and the first molar showed an overall mesial inclination with mesial crown eversion.Therefore,in the adduction cases of mandibular tooth extraction,attention should be paid to the lingual movement of the second premolar,which could be offset by corresponding techniques in clinic.The trend of anterior tooth displacement in all directions:from condition A to condition D,in the sagittal direction,the difference value in crown-root displacement of central incisors changed from-11.891 μm to-5.757 4 μm,indicating that the central incisor changes from oblique movement to overall movement.The difference value in crown-root displacement of lateral incisors changed from-11.828 1 μm to-6.711 45 μm,and that of canines changed from-7.572 3 μm to-4.695 5 μm,indicating that the oblique movement of the lateral incisors and canines is also changing to an overall movement.In the vertical direction,from condition A to condition D,the reduction of incisors was gradually increased,while that of canines was gradually decreased.These findings indicate that the stretching length of the wing can affect the oblique movement trend of the anterior teeth.As the wing continues to stretch,the torque control of the lower anterior teeth will become better.