OBJECTIVETo investigate the effectiveness of different surface treatments that could promote the bond strength of composite resin to commercially pure titanium.

METHODSThe 24 casting pure titanium specimen were randomly divided into four groups: Smooth group, rough group, acid etching smooth group, acid etching rough group. Each group had six specimens. In the different groups, the specimens were treated respectively under different surface treatments. The specimens of rough group was sandblasted, the acid etching smooth group was treated by acid etching, the acid etching rough group was treated by acid etching after sandblasting, the smooth group had no treatment. After surface treatment, the casting pure titanium specimens that were veneered by composite resin became titanium-composite resin specimen. Then the bond strengths were evaluated by universal testing machine and the surfaces were observed by scanning electron microscope including titanium surface appearance and titanium surface appearance of different groups after shear test.

RESULTSThe bond strengths of smooth group, rough group, acid etching smooth group, acid etching rough group were (3.08 +/- 0.45), (6.05 +/- 0.74), (6.27 +/- 0.80), (10.16 +/- 0.82) MPa, respectively. The statistical analysis showed that the bond strengths in rough group, acid etching smooth group, acid etching rough group were higher than in smooth group (P < 0.01). The highest bond strength was the acid etching rough group. There were no significant differences in the bond strength between rough group and acid etching smooth group (P > 0.05). There were some different titanium surface appearances in each group before and after testing.

CONCLUSIONTitanium surface treatment of sandblasting and etching can improve the bond strength between titanium and composite resin. The pre-treatment of sandblasting before etching is an effective modification method of titanium for bonding to composite resin.

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

Objective To compare the safety and efficacy of direct and remedial rotational atherectomy in the treatment of heavily calcified coronary artery lesions.Methods We retrospectively reviewed 58 patients admitted in the Shanghai Chest Hospital and Liaocheng People Hospital from May 2012 to July 2015 who had received stent implantation and rotational atherectomy.The 58 patients were divided into two groups which were the direct atherectomy group (n =27) and the remedial atherectomy group (n =31).General clinical date,lesion and procedural characteristics,intraoperative complications,in-hospital and follow-up MACCE were compared between the two groups.Results There were no differences between the two groups in general clinical date intraoperative complications,amount of contrast agent used,proceduraltime,rates of in-hospital and follow-up MACCE.Nevertheless,compared with the direct artherectomy group,the remedial group had more number of balloon dilations during procedure [3 (1,5) vs.2 (1,2),P ＜ 0.001] and higher peak cardiac troponin levels [1.1 (0.3,3.0) μg/L vs.0.5 (0.1,2.3) μg/L,P =0.032].Conclusions Remedial rotational atherectomy with drug-eluting stent had the same safety and efficacy as direct atheretomy with drug-eluting stent in treating patients with heavily calcified coronary lesions.It is reasonable and safe to transform routine PCI to remedial rotational atherectomy when the 2.0 mm semi compliant balloon or/and 2.5 mm non-compliant balloon cannot pass through or dilate the lesions.

Objective To investigate the etiological characteristics of food poisoning isolates of Vibrio parahaemolyticus (VP) from 2019 to 2021 in Zhongshan City. Methods A total of 37 strains of Vibrio parahaemolyticus isolated from 8 food poisoning incidents in Zhongshan City from 2019 to 2021 were collected, including 1 residual food isolate and 36 human isolates. The genetic correlation of Vibrio parahaemolyticus food poisoning isolates in this region was analyzed by serological typing, virulence gene detection (TLH, TDH, and TRH), drug sensitivity test, pulsed field gel electrophoresis (PFGE) and multipoint sequence typing (MLST). Results The 37 strains of Vibrio parahaemolyticus were divided into 4 serotypes: O3:K6, O10:K4, O4:K8, and O4:KUT. The tdh+ and trh- were the main virulence genotypes, accounting for 97.30% (36/37). The drug resistance rate of cefazolin was 40.54% (15 strains R, 22 strains I), and no multidrug-resistant strains were found. The 37 VP strains were divided into 23 PFGE types and 6 cluster groups, with correlation coefficients ranging from 60.4%-100%. The multipoint sequencing typing showed that the 37 VP strains were divided into 9 ST types and 3 complex groups, of which ST3 type was the main type (23 strains, 62.1%). Conclusion This study has found that the dominant virulence types of Vibrio parahaemolyticus food poisoning isolates in Zhongshan City from 2019 to 2021 are tdh⁺ and trh^-, and 37 representative strains can be divided into 6 PFGE clusters and 9 ST types with MLST type being mainly ST3. This study has identified the rare serotype O10:K4 which has caused an increase in the proportion of food poisoning events, suggesting that we should strengthen detection and be alert to the risk of continued local epidemics of new rare serotype strains.