OBJECTIVETo investigate the influence of three primers on the shear bond strength between cast titanium (Ti) and composite resin.

METHODSThe disks (n = 40) were cast by commercially pure (CP) Ti, which diameter were 8 mm and thick were 3 mm. The titanium surfaces were polished with silicon carbide sand papers under running water and then treated by sandblasting and acid (4%HF) etching. They were divided into four groups: control group (group A), treated with KH-570 (group B), treated with Alloy Primer (group C), treated with Metal photo primer (group D). After treatment, the specimens were evaluated for their shear bond strengths by universal testing machine. The values were statistically analyzed. The fractured surfaces were observed by scanning electron microscope (SEM).

RESULTSThe shear bond strengths of group A, B, C, D were (9.773 +/- 0.67), (11.463 +/- 0.82), (14.224 +/- 0.75), (13.157 +/- 0.73) MPa. There were significant differences in bond strength between A and B, C, D (P < 0.01). B and C, D had significant differences (P < 0.01). C and D had no significant differences (P>0.05).

CONCLUSIONKH-570, Alloy Primer, Metal photo primer significantly improve the bond strength of ceramage composite resin to cast titanium. KH-570 group bonding strength is lower than the the Alloy Primer group and Metal photo primer group.

Composite Resins ; Dental Bonding ; Materials Testing ; Methacrylates ; Shear Strength ; Silanes ; Silicates ; Thiones ; Titanium

OBJECTIVEThis study aims to investigate the effects of post-cure heat treatment (PCHT) on the bond strength of Ceramage composite resins for titanium casting using different surface treatments.

METHODSMetal specimens (n=30) were randomly divided into following five groups: polishing (group A), sandblasting (group B), acid etching after sandblasting (group C), PCHT after sandblasting (group D), and PCHT after sandblasting and acid etching (group E). The specimens were then processed and coated with Ceramage composite resins according to the grouping. After treatment, the shear bond strengths and microhardness of the specimens were evaluated. The fracture surface morphology of the titanium-Ceramage composite resin was observed using a scanning electron microscope.

RESULTSThe shear bond strengths of groups A to E were (5.92 +/- 0.54), (10.25 +/- 0.55), (14.97 +/- 0.88), (14.41 +/- 0.63), and (19.95 +/- 0.52) MPa, respectively. No statistical difference was found between groups C and D, whereas the rest of the groups showed statistically significant differences (P < 0.01). Visible polymerization residues were found on titanium porcelain metal surface of groups B to E. The microhardness values of groups D and E were higher than those of groups B and C (P < 0.05).

CONCLUSIONPCHT significantly improves the bond strength and surface microhardness of Ceramage composite resins for titanium casting.

Acid Etching, Dental ; Composite Resins ; Dental Bonding ; Dental Porcelain ; Hot Temperature ; Materials Testing ; Shear Strength ; Silicates ; Surface Properties ; Titanium

Objective:To compare the efficacy and safety of bi-level positive airway pressure (BiPAP) ventilation and heated humidified high flow nasal cannula (HHHFNC) ventilation as initial respiratory support for premature infants with respiratory distress syndrome (RDS).Methods:From January 2019 to June 2021, premature infants [gestational age (GA) 28~35 weeks)] with grade Ⅰ to Ⅲ RDS admitted to Suining County People's Hospital were prospectively enrolled. The infants were randomly assigned into BiPAP group and HHHFNC group. The clinical characteristics, ventilation efficacy and complications were analyzed.Results:A total of 33 infants were in BiPAP group and 32 in HHHFNC group. No significant differences existed between the two groups in the following items: the frequency of apnea within 24 h of ventilation, FiO 2 and PaCO 2 at 24 h, the use of pulmonary surfactant (PS), the incidence of non-invasive ventilation failure within 72 h, non-invasive ventilation duration and the age achieving total enteral nutrition. HHHFNC group had lower score in premature infants pain profile (PIPP) than BiPAP group at 24 h of non-invasive ventilation [4 (3, 6) vs. 8 (6, 11), P<0.001]. No significant differences existed in nasal injury, pneumothorax, intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia and mortality rate between the two groups ( P>0.05). Conclusions:As the initial treatment for premature infants with grade Ⅰ to Ⅲ RDS, BiPAP and HHHFNC has similar rates of non-invasive ventilation failure within 72 h,non-invasive ventilation duration and adverse events. HHHFNC may ease the pain of the infants.

Objective To investigate the effect of exosomes derived from Echinococcus multilocularis on macrophage polarization after treatment for different durations and concentrations. Methods A total of 60 BALB/c mice were used for modeling, among which 4 mice were selected to observe the growth of abdominal lesions on 7.0T MRI. The mice for modeling were dissected, and the protoscoleces was taken from the abdominal lesion and cultured in vitro ; ultracentrifugation was used to extract the exosomes from the supernatant, and transmission electron microscopy and Western blotting were used for the characterization of exosomes. The macrophages without exosome treatment were established as control group, and the macrophages co-cultured with different concentrations of exosomes derived from Echinococcus multilocularis were established as experimental group (10 μg/mL group and 50 μg/mL group) and were cultured for 48 and 72 hours. The morphological changes of macrophages were observed under a microscope, and flow cytometry and ELISA were used to observe polarization state. A one-way analysis of variance was used for comparison of normally distributed continuous data between multiple groups, and the least significant difference t -test was used for further comparison between two groups. Results The results of 7.0T MRI showed the formation of diffuse lesions with different sizes in the abdominal cavity of mice, and the exosomes derived from Echinococcus multilocularis were approximately 100 nm in diameter and were cup-shaped or saucer-shaped, with the positive expression of the surface markers CD9, TSG101, and CD63. After co-culture, most of the cells in the experimental group were elongated with an irregular and polygonal shape. Flow cytometry showed that after 48 hours of co-culture, the positive rates of CD16/32, CD206, and CD369 in the control group were 99.53%±0.06%, 90.27%±0.21%, and 2.40%±0.20%, respectively; compared with the control group, except that the 10 μg/mL exosome group had a significant reduction in the positive rate of CD369 (0.80%±0.00%) ( P < 0.05), all the other groups had a significant increase in the positive rates of CD16/32, CD206, and CD369 (all P < 0.000 1); after 72 hours of co-culture, the positive rates of CD16/32, CD206, and CD369 in the control group were 99.67%±0.06%, 85.47%±0.55%, and 6.60%±0.20%, respectively, and compared with the control group, the experimental group had significant increases in the positive rates of CD16/32, CD206, and CD369 (all P < 0.05). ELISA showed that after 48 hours of co-culture, the levels of IL-6 and TNFα in the control group were 58.53±15.52 pg/mL and 320.70±5.30 pg/mL, respectively, and when the exosome concentration was 50 μg/mL, the level of IL-6 in the experimental group was 98.81±15.55 pg/mL, which was higher than that in the control group ( P < 0.05); after 72 hours of co-culture, the levels of IL-6 and TNFα in the control group were 76.22±9.68 pg/mL and 323.90±87.37 pg/mL, respectively, and when the exosome concentration was 10 μg/mL, the level of TNFα was 164.20±14.17 pg/mL, which was significantly lower than that in the control group ( P < 0.05); when the exosome concentration was 50 μg/mL, the level of IL-6 was 99.52±8.35 pg/mL, which was significantly higher than that in the control group ( P < 0.05). Conclusion Exosomes derived from Echinococcus multilocularis can regulate macrophage polarization and induce M2-like polarization of macrophages after co-culture at a concentration of 10 μg /mL for 72 hours, and further studies are needed to clarify the specific method.