Three-dimensional analysis of maxillary dentition during molar distalization with clear aligners under different movement designs: an in vitro experiment / 中华口腔医学杂志

Objective: To investigate the three-dimensional force in the maxillary dentition under different movement designs for molar distalization with clear aligners Methods: Three groups were designed: simultaneous movement group (simultaneous distalization of maxillary first and second molars), second molar movement group (distalization of maxillary second molars) and first molar movement group (distalization of maxillary first molars). Ten clear aligners were made in each group, and the displacement was designed to be 0.2 mm. A force sensing device was established to measure the three-dimensional force on the upper dentition with the clear aligner. The device contained a model of the maxillary dentition consisting of 14 teeth, each tooth connected to an individual sensor. After the clear aligner was fitted, the data of 14 sensors were collected and analyzed using computer analysis software. The moving teeth were taken as the target teeth, and the rest of the teeth were anchorage. The data of the three-dimensional force in the three groups in each tooth position were measured and compared. Results: The sagittal forces on the first and second molars in the simultaneous movement group were (5.61±0.94) and (5.81±1.08) N, respectively, which were significantly smaller than those of the target teeth in the same position in other groups (P<0.05). The second molars in the first molar movement group received a sagittal reaction force, which was (-6.73±1.99) N. The anterior teeth in the three groups were all subjected to sagittal reaction force, and the force value was in a range of (-3.33 to 0.46) N. In the coronal direction, the second premolars of the simultaneous movement group received the reaction force in the palatal direction, and the force value was (-2.17±1.06) N. The first molars in the second molar movement group were also subjected to palatal reaction force of (-1.99±0.70) N. The second molars and second premolars in the first molar movement group were also subjected to palatal reaction force, which were (-2.85±0.57) and (-1.85±0.74) N, respectively. Compared with the sagittal and coronal forces, the target teeth and anchorage teeth in the three groups were less stressed in the vertical direction. Conclusions: The first and second molars distalized simultaneously, the correction force in the sagittal direction was relatively small. When first molar was moved distally alone, a greater reaction force in the sagittal direction was exerted on the second molar. Buccal displacement of the adjacent anchorage teeth should be designed to counteract the palatal reaction force on the anchorage teeth as the molars moved distally.

Neuroprotective Effect and Mechanisms of Notoginsenosides：A Review / 中国实验方剂学杂志

Notoginsenosides， the saponins extracted from Panax notoginseng， have many pharmacological effects， such as anti-inflammation， anti-oxidation， anti-tumor， nervous system and cardiovascular system protection， microcirculation improvement and calcium overload inhibition. At present， notoginsenosides are widely used clinically for treating many diseases with good efficacy， especially for nervous system diseases such as stroke， stroke sequelae and Alzheimer's disease. In recent years， the mechanism underlying their neuroprotective effect has been continuously explored. To advance the applied research on notoginsenosides in the prevention and treatment of central nervous system diseases， this paper， combined with the latest reports， summarizes their neuroprotective effect and mechanisms in terms of regulating voltage-gated ion channels， protecting nerve cells and neurovascular unit， inhibiting oxidative stress and inflammatory reaction， promoting angiogenesis and reducing excitatory neurotoxicity. Although the protective mechanism of notoginsenosides for the nervous system mainly involves the above several aspects， some of them still remain to be fully elucidated， which necessitates the further exploration of neuroprotective effect of notoginsenosides with molecular biology， metabolomics， proteomics and other technologies.

Effect of a desensitizing polishing paste on bonding strength of two self-etching adhesives to dentin / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of an 8% arginine-CaCO3 containing desensitizing polishing paste on bonding strength of two self-etching adhesives to dentin.</p><p><b>METHODS</b>Thirty-six intact human premolars extracted for orthodontic reasons were collected within 1 month after extraction and randomly assigned into three groups using a table of random numbers (n = 12): specimens without any treatment served as control. In the polishing powder group specimens were polished with a slurry of pumice, and in the desensitizing polishing paste group dentin surfaces of the sample teeth were treated with 8% arginine-CaCO3 containing desensitizing polishing paste. Then each group was divided into two sub-groups using a table of random numbers in order to evaluate the bonding strength of two self-etching adhesive agents (G-Bond, GC; Fl-Bond II, Shofu). Microtensile bond strength test was conducted immediately and after 5000 thermocycling (n = 15). Scanning electron microscope (SEM) was used to evaluate the occluding effect of the desensitizing polishing paste.</p><p><b>RESULTS</b>In the pre-thermocycling stage, there were no significant differences in Fl-Bond II bonding strength among the three groups [control: (30.34 ± 5.42) MPa, polishing powder group: (29.72 ± 5.16) MPa, desensitizing polishing paste group: (31.53 ± 4.86) MPa] (P > 0.05). However there were significant differences among the three groups in G-Bond bonding strength [control: (38.19 ± 4.42) MPa, polishing powder group: (36.47 ± 4.72) MPa, desensitizing polishing paste group: (46.88 ± 7.83) MPa] (P < 0.05). After thermocycling process, there were no significant differences in bonding strength among the three groups in both G-Bond groups and Fl-Bond II groups. SEM observation showed that the desensitizing polishing paste could occlude open dentinal tubules effectively, and the application of self-etching adhesives could re-open the dentinal tubular orifices. An even layer can be seen on the dentin surface treated with self-etching adhesive containing functional monomers.</p><p><b>CONCLUSIONS</b>The 8% arginine-CaCO3 containing desensitizing polishing paste could effectively occlude dentinal tubules, thus may have potential benefits in preventing post-operative sensitivity. Additionally, it had no adverse effect on bonding strength of self-etching adhesives to dentin.</p>

Study on the micropermeability of resin-dentin bonding interfaces with ethanol-wet bonding technique / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the micropermeability on bonding hydrophobic adhesive to dentin with ethanol-wet bonding under simulated pulp pressure.</p><p><b>METHODS</b>Twenty-four intact human third molars were used in the study. After the enamel of occlusal surfaces was removed, the molars were randomly divided into six groups. Adper Scotchbond Multi-Purpose was used in the control group; in the experimental groups, the dentin surfaces were saturated with ethanol for 20 s (group 1), 1 min (group 2), 2 min (group 3), 3 min (group 4) or with a series of increasing ethanol concentrations before application of hydrophobic adhesive (group 5). All the bonding procedures were done under simulated pulp pressure. After 24 hours, micro-tensile bond strength test were performed on the specimens. Bonding interfaces were observed under laser scanning confocal microscope (LSCM) after the pulp chamber were filled with a water-soluble fluoroprobe rhodamine B for 3 hours.</p><p><b>RESULTS</b>Compared with the control group [(38.14 ± 4.97) MPa], bond strengths in group 1 [(21.02 ± 7.23) MPa] and group 2 [(29.64 ± 3.81) MPa] were statistically lower (P > 0.05), while bond strength in group 3 [(38.40 ± 5.03) MPa], group 4 [(37.26 ± 4.68) MPa] and group 5 [(40.12 ± 5.95) MPa] were similar to the control group (P < 0.05). The images taken by LSCM showed that with extension of ethanol-wet time, the deposition of fluorescent dye in hybrid layer and along the dentinal tubules decreased gradually. Especially in group 5, only spare fluorescent dye deposition could be detected in the hybrid layer.</p><p><b>CONCLUSIONS</b>Dentin saturated with ethanol for more than 2 min before bonding hydrophobic adhesive to dentin could provide favorable bond strength and decreased the micropermeability of bonding interfaces under simulated pulp pressure.</p>

Relationship between type 2 diabetic retinopathy and the carotid artery intima-media thickness / 中国地方病学杂志

Objective To explore the relationship between the diabetic retinopathy (DR) and the carotid artery intima-media thickness(IMT) in type 2 diabetic patients to reveal the relationship between macroangiopathy and microangiopathy in diabetic patients further. Methods One hundred and tweenty-three diabetic cases in patient chosen from 2008 to 2009 were divided into diabetic retinopathy group(DR) and non-diabetic retinopathy group(NDR) by fundus examination. The patients were asked about their disease history including durations, smoking and so on. Meanwhile the carotid artery IMT, systolic pressure (SBP), diastolic pressure (DBP), serum total cholesterol, triglycerides, high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol, glycosylated hemoglobin(HbAlc), body mass index(BMI) were measured of all the cases. The incidence of increased carotid artery IMT was cmpared with χ2 test, as well as the average IMT between the two groups, the influencing factors artery IMT was 50.98%(26/51) in DR group, and 33.33%(24/72) in NDR group, having a statistically significant showed the diabetic retinopathy risk factors were smoking(χ2=6.20, P<0.05), duration(t=-4.13, P<0.01). carotid artery IMT(t=-2.21, P<0.05), SBP(t=-2.37, P<0.05), and HDL-cholesterol(t=4.49, all P<0.01). 12.77, all P<0.01), carotid artery 1MT and smoking(χ2=6.05,4.15, all P<0.05). Conclusions Type 2 diabetic patients complicated with DR have a prominent increase in IMT thickening proportion and average IMT, which reveals the relationship between the DR and the IMT.