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Polyolefin elastomer (POE) has very weak crystalline ability, consequently, applying the conventional preparative temperature‐rising elution fractionation (P‐TREF) to separate is challenging. Here, a unique, home‐built P‐TREF apparatus with an extensive range of temperatures from −80°C to 150°C is applied to first fractionate POE depending on its crystallizability. The main fractions are eluted at 0°C, 8°C, 15°C, 20°C, 25°C, 30°C, and 35°C. The corresponding weight percentages of fractions are 8.31, 13.38, 15.59, 12.05, 13.39, 17.30, and 10.53 wt%, respectively. The chain structures of fractions are further analyzed by high‐temperature gel permeation chromatography (HT‐GPC), 13C‐nuclear magnetic resonance spectroscopy (13C‐NMR), differential scanning calorimetry (DSC), and successive self‐nucleation and annealing (SSA). The crystallinity of the fraction grows continually as the elution temperature rises. The 1‐octene comonomer concentrations within the fractions decreases from 13.8 to 7.9 mol% when the elution temperature rises from −10°C to 40°C. These findings enable for the detailed recognition of the chain microstructure of POE resin and the extension of the TREF approach to POE resins. This lays the groundwork for fundamental studies and practical uses in industry. [ABSTRACT FROM AUTHOR]

Objective: To investigate the proliferative potential of the epithelial cells in odontogenic keratocyst, radicular cyst, dentigerous cyst and ameloblastoma., Methods: DNA contents and ploidy of basal and spinous cells in keratocyst, radicular cyst, dentigerous cyst, and the peripheral column cells and central reticular cells in ameloblastoma were analysis respectively., Results: The more and higher DNA contents and the proliferating ploidy of keratocyst and ameloblastoma than those of radicular cyst and dentigerous cyst indicate the active proliferating potential. The spinous cells showed more active proliferating growth than the basal cells of keratocyst. The higher DNA contents of radicular cyst are related to the stimulus of the inflammation. The dentigerous cysts have more di-ploidy cells without active growth potential., Conclusions: The active cell proliferating growth in keratocyst and ameloblastoma is probably the pathological basis of their local aggressive biological behavior.

Objective: To investigate the activities of head, neck and upper trunk muscles with mandibular movement in normal adults., Methods: The integral data of surface electromyography (EMG) had been recorded to analyze the activities of anterior temporal (Ta), posterior temporal (Tp), sternocleidomastoid (SCM) and trapezius (TRAP) muscles with mandibular movement in ten normal adults., Results: The former mentioned muscles acted constantly when the mandible was in the rest position. The activities of Ta, Tp and SCM muscles increased with protrusion of mandible, mouth opening, tapping, maximum clenching, and chewing movements. The amplitudes of the increased activity of these muscles were correlated significantly with each other. When the activities of Ta and Tp muscles increased to 56 times and 25 times respectively, the activity of SCM muscle increased to 5 - 6 times. The activity of trapezius muscle increased with protrusion of mandible and opening movement, but tended to stop with the maximum clenching and chewing movement. The correlations of left and right sides of the same muscles had been found., Conclusions: The muscles of head, neck and upper trunk can act as contributors to keep the mandibular positions and take part in the mandibular movements.

Objective: To study the methodological techniques in measuring the severity of temporomandibulr disorders (TMD) and in evaluating the effectiveness of therapies in clinic., Methods: Both Fricton's Craniomandibular Index (CMI) and Helkimo's Clinical Dysfunction Index were calculated from 60 TMD patients. Inter-rater reliability was tested to assess the consistency in use between different examiners. Fricton's CMI was used to assess the clinical improvement after accepting a treatment in 21 TMD patients diagnosed as acute disk displacement without reduction., Results: Correlation Coefficient for inter-rater reliability in two groups was 0.879 and 0.939 respectively for Fricton's CMI and 0.744 and 0.838 for Helkimo Clinical Dysfunction Index. Fricton's TMJ dysfunction index was decreased from 0.337 to 0.021 (P < 0.001) and Fricton's CMI was decreased from 0.185 to 0.011 (P < 0.001) after the treatment in 21 TMD patients with disk displacement without reduction., Conclusions: To avoid using subjective and descriptive report in assessment of the severity of TMD and the effectiveness of therapies, Fricton's CMI is recommended as an objective criteria which is simple in clinical use, and ease in scoring.

Objective: To develop a dental CAD/CAM system with the autonomic intellectual property., Method: 28 standard teeth crowns were scanned using a newly 3-D laser scanner. As a development platform the Matlab 5.3 were used to process the acquired data, also be used to define the characterized areas on the surfaces of the crowns and to change the crowns form. The software of Surfacer 10.5 to develop a new CAD software for fixed prosthetics, and the 3.5 axis numerical controlled machine to manufacture the prosthetics were used., Result: It is the first time, the 3D graphic data bank of Chinese teeth crowns with a standard form was established. A software of the occlusal adjustment and the form modification were developed. It is also the first time, the authors realized the whole process to use the CAD-CAM for the manufacture of a crown., Conclusion: The successful result shows, that we have already mastered well the base theory, the mathematics method, the technology of a CAD-CAM system. It provides the basics for the future development.

Objective: To investigate an available method for quantitative diagnosis of zygomatic fractures to quantitatively classify and diagnose the deformities of zygomatic fractures., Methods: Traditional X-ray, two and three dimensional CT images of 96 patients with zygomatic fractures were measured and analysed by computer-assisted measuring system before and after operation to diagnose the displacement and deformity of the fractures., Results: 1. Using anthropology points and computer assisted measuring system, a new method was established to assess the displacement of the zygomatic fractures. 2. Displacement of the zygomatic fractures was approximately diagnosed by measuring different angle of 3D CT photographs. 3. A classification was proposed based on the deformities of the zygomatic fractures., Conclusions: Computer-assisted 3D CT measuring system is accurate, reliable and feasible in clinic for diagnosing zygomatic fractures.

Objective: To study the activities of head, neck and upper trunk muscles during mandibular movements in healthy adults and mandibular asymmetry patients., Methods: Electromyographic integrogram was used to record and analyze the electromyographic activities of the anterior temporal (Ta), posterior temporal (Tp), sternocleidomastoid (SCM), and trapezius (TRAP) muscles in rest position and during mandibular movement among 10 normal adults and 10 mandibular asymmetry patients., Results: All the four muscles showed constant electromyographic activities when the mandible was in the rest position. The activities of Ta, Tp, and SCM muscles increased with protrusion of mandible, mouth opening, tapping, maximum clenching, and chewing. The activities of Ta and Tp muscles of the patients were 1.7 times greater than that of the normal adults during mandibular movement without occlusion, and were weaker by 50% during mandibular movement with occlusion. The difference between electromyographic activities during mandibular movement and in rest position was less among patients than among normal adults. The TRAP muscle of the patients showed constant electromyographic activities with the activity volume nearly 1.8 times that of the normal adults. The difference between the muscle and its namesake at the opposite side was greater among the patients (21%) than among the normal adults (8%)., Conclusion: All the four muscles participate in the maintenance of rest position of mandible and the realization of mandibular movements. The coordination of muscular activities among mandibular asymmetry patients is poorer than that among normal adults.

Objective: To study the role of mitogen-activated protein kinase (MAPK) pathway in the action mechanism of PYM-induced KB cell apoptosis., Methods: Western blot analysis was used to investigate the expression of the mitogen-activated protein kinase., Results: When treated with PYM in cultured KB cells, the extracellular signal-regulated kinase (ERKl/2) showed a dose-and time-dependent decreasing in phosphorylation status of these proteins through a western blot analysis, whereas protein levels of p38 MAPK remained unchanged., Conclusions: The mitogen-activated protein kinase (MAPK) pathway may play an important ro1e in PYM-induced apoptosis of KB cells.

Objective: To evaluate a new treatment method for temporomandibular joint acute disk displacement without reduction., Methods: Twenty-one patients diagnosed as acute anterior disk displacement without reduction were treated by manipulation with the aid of joint cavity extension followed by anterior repositioning splint. All and eleven of twenty-one patients were re-examined two weeks after insertion of splint and at the end of treatment (3 approximately 6 months later)., Results: (1) Degree of maximum mouth opening was increased from 25.8 mm before treatment to 46.6 mm 2 weeks after, 48.1 mm at the end of treatment; (2) Mean pain level (VAS) dropped from 2.62 before treatment to 0.43 2 weeks after, 0.18 at the end of treatment; (3) Fricton's TMJ dysfunction index and craniomandibular index decreased from 0.337 and 0.185 respectively before treatment to 0.021 and 0.011 respectively 2 weeks after, 0.031 and 0.018 respectively at the end of treatment., Conclusions: The treatment method should be considered for acute anterior disk displacement without reduction if medication and physical therapy failed to have disk successfully reduced.

OBJECTIVE: To evaluate the feasibility of transplanting composite mandibular allografts to repair large mandibular defects. METHODS: Three composite mandibular trans-plantation models were established. The first model consisted of hemimandible with the attached teeth, muscle and skin,and oral mucosa. The second model was transplanted in the same way with the first one excluding oral mucosa and some teeth, and third one excluding the oral mucosa and all dental crowns. Fourteen transplanting operations were performed in canines. Cyclosporine A and methylprednisone were given for immunosuppression. RESULTS: The composite mandibular organs had an effective and closed return circuit. Transplantation of vascularized allograft of mandibular compound organs was feasible. Two longest time survivors of 67 d and 76 d were in the third model group. Cyclosporine A was successful in suppressing rejection of transplanted composite allograft and prolonging survival time of transplantation models. CONCLUSIONS: The composite mandibular allografts were available with large block of living composite tissue, and helpful in restoration of appearance and function for severe mandibular defects.

OBJECTIVE: To study the effects of occlusal trauma on the ultra-structure of synovial membrane and articular cartilage in rabbit's temporomandibular joints (TMJ). METHODS: TMJs from six rabbits with occlusal trauma and three control rabbits were studied by transmission electron microscopy. RESULTS: Degenerative changes in synovial membrane and articular cartilage of TMJ were induced following occlusal trauma. The structure of the articular surface was damaged, and chondrocytes in cartilage showed signs of degeneration. The synovial lining cells contained dense accumulations of vimentin intermediate filaments (IFs), which were especially prevalent in the cellular processes as well as paranuclearly. Microvilli on the synovial cell membrane were commonly seen. The "vermiform bodies" in the deeper interstitium of the synovial tissue were also found. Our findings of the punctate adherens between synovial lining cells were described in detail. CONCLUSIONS: The occlusal trauma is really a factor inducing degenerative changes of the TMJ.