Effect of water immersion on a dental self-healing and antibacterial resin composite / 华西口腔医学杂志

OBJECTIVE@#This investigation aimed to develop a novel self-healing and antibacterial dental resin composite. The effects of water immersion on its properties were also evaluated.@*METHODS@#Microcapsules filled with healing agent of triethylene glycol dimethacrylate were synthesized on the basis of previous studies. Antibacterial resin composite contained nano-antibacterial inorganic fillers that were modified by quaternary ammonium salt with long-chain alkyl. Microcapsules were incorporated into antibacterial resin composite at mass fraction of 7.5%. A commercial resin composite named Tetric N-Ceram was used as control. The resin samples were immersed in 37 °C distilled water for different periods. A flexural test was used to measure the mechanical properties of the novel resin composite. A single-edge V-notched beam method was used to measure fracture toughness and self-healing efficiency. A dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony-forming units (CFU) and lactic acid production of biofilm on the novel resin composite were calculated to test the antibacterial property.@*RESULTS@#Mechanical properties and fracture toughness decreased significantly after the composite was immersed in water for 30 days (P0.05). Water immersion did not weaken the self-healing capability of the composite (P>0.05), and self-healing efficiency of 64% could still be obtained even after 270 days. The antibacterial resin composite showed a strong inhibition effect on the biofilm metabolic activity versus water immersion time from 1 day to 270 days. Therefore, the composite could still have a promising antibacterial property even after being immersed in water (P<0.05).@*CONCLUSIONS@#Water immersion could weaken the mechanical properties of the novel self-healing and antibacterial resin composite, but it insignificantly affected the self-healing and antibacterial properties of the composite.

Anatomical and biomechanical characteristics of sternoclavicular joint / 中国组织工程研究

BACKGROUND: The clinical experience of the treatment of the sternoclavicular joint dislocation and peripheral fracture is relatively lacking, but its incidence is increasing yearly. At present, there are few studies on the anatomy and biomechanics of the sternoclavicular joint in and outside China, and no systematic anatomical measurements of the sternoclavicular joint are reported. OBJECTIVE: To provide a biological reference for the clinical diagnosis and treatment of sternoclavicular joint dislocation or peripheral fractures by studying the anatomy and biomechanics of the sternoclavicular joint. METHODS: (1) A total of 16 specimens (32 sides) of adult antiseptic and moist cadaveric specimens were selected. The complete manubrium, bilateral clavicle and surrounding tissues of sternoclavicular joint were anatomically separated, and repair to bone-ligament-bone specimen models. (2) The areas of manubrium articular surface and the medial clavicular articular surface of all specimens were measured by the ink pattern combined with grid counting method. (3) The morphological features of the anterior and posterior sternoclavicular ligaments of the specimens in this group were observed, and the length, width and thickness were measured and analyzed statistically. (4) The left and right sternoclavicular joints of each specimen were randomly paired into A and B groups. Group A received simply cutting of anterior sternoclavicular ligament. Group B received simply cutting of posterior sternoclavicular ligament. Before and after cuting off the ligament, the anterior and posterior load experiments were performed on the anatomical sites with the same force arm length and perpendicular to the distal clavicle. The angles of joints and load-angle regression line slopes were compared between the two groups in the anterior and posterior directions load. RESULTS AND CONCLUSION: (1) The area of articular surface of manubrium (239.00±28.78 mm2) was smaller than the area of medial articular surface of the clavicle (482.56±44.89 mm2), and the difference was statistically significant (t=-40.105, P < 0.001). (2) The length, width and thickness of the anterior sternoclavicular ligament were (17.56±1.94 mm), (15.54±1.42 mm) and (1.93±0.32 mm), and the length, width and thickness of the posterior sternoclavicular ligament were (17.21±1.86 mm), (15.97±1.17 mm), and (2.07±0.29 mm) respectively;there was no significantly statistical difference in the length, width and thickness between them (P > 0.05). (3) Before cutting the ligaments, when the loads were 2, 4, 6, 8, and 10 N, the angle backwards of joint caused by loads in the forward direction was less than the angle of forwards of joints caused by loads in the backward direction, but only when the loads were 6, 8, and 10 N, the difference between them was statistically significant (P < 0.05). The slope of the regression line of load-angle for the loads in the forward direction was less than the slope of the regression line of load-angle for the loads in the backward direction, with statistical difference (F=31.413, P < 0.001). After the ligaments were cut, when the loads were 2, 4, 6, 8 and 10 N in the forward direction in group A and group B, the backward angulation of joint in group A was less than that in group B (P < 0.05). The slope of the load-angled regression line in group A was less than that in group B (F=52.224, P <0.001). When the loads in the backward direction in group A and group B were 2, 4, 6, 8 and 10 N, the forward angulation of joint in group A was greater than that in group B (P < 0.05), and the slope of the load-angled regression line in group A was greater than that in group B (F=12.503, P=0.008). (4) These results suggest that contact area between the articular surface of the medial clavicle and the articular surface of the manubrium is narrow, which determines the instability of the joint itself. The sternoclavicular ligament is extremely important for maintaining the joint stability. The forward angulation of joint restriction effect of sternoclavicular ligament was weaker than that of the backward angulation, also because of the joint in the anatomical position of the natural forward angulation, so the sternoclavicular joint was prone to anterior dislocation. It is necessary to pay attention to the repair and reconstruction of sternoclavicular ligament when sternoclavicular joint dislocation or peripheral fractures are treated by operations.

Identification of different varieties of Rhei Radix et Rhizoma based on chemical analysis / 中国中药杂志

A HPLC method was established to determine the contents of the five anthraquinones and rhaponticin in the different varieties of Rhei Radix et Rhizoma. The difference existed in different varieties. The results showed that rhein and rhaponticin were marker substances which could be used to distinguish palm leaf groups rhubarb and wave leaf groups rhubarb. Authentic rhubarb didn't contain rhaponticin. Falsify rhubarb contains trace amounts of rhein. Rheum tanguticum contains abundant rhein. The ratio value of the content of rhein to chrysophanol could be used to distinguish R. tanguticum from the other two authentic varieties (R. palmatum and R. officinale). The content of rhaponticin varied largely in different varieties of wave leaf groups rhubarb.

Surgical treatment for rotationally and vertically unstable pelvis fracture / 中国骨伤

<p><b>OBJECTIVE</b>To study the clinical results of surgery for rotationally and vertically unstable pelvis fracture.</p><p><b>METHODS</b>Thirty-four patients with rotationally and vertically unstable pelvis fractures were treated. There were 23 male and 11 female,with the average age of 36 years ranging from 13 to 56 years. There were 9 cases of type APC III, 14 cases of type LC III, and 11 cases of type VS according to Young-Burgess Classifiction. All patients' pelvis were treated with temporary external fixation after hospitalization, and were treated with open reduction and internal fixation through anterior approach after stabilization of body condition.</p><p><b>RESULTS</b>All patients were followed up for 12 to 48 months (average 21 months). All the incisions healed well, and the fractures got union for 3 to 6 months. According to the Majeed evaluation, the results were excellent in 21 cases, good in 10, fair in 3. All patients were not remained deformity of rotation and dislocation. But 3 patients remained lameness, 4 remained low back pain, 3 remained both leg and feet numbness.</p><p><b>CONCLUSION</b>In the management of the rotationally and vertically unstable pelvis fractures, a stable pelvis can be reconstructed by effective open reduction and internal fixation through the anterior approaches, so that further sequelae can be reduced.</p>