BACKGRoUND:The clinical manipulation properties of light-cured composite resin,such as flowing property.filling capacity,shaping and stability has not unified definition in dental materials notwithstanding more studies of rheological behaviors were undertook.OBJECTIVE:To explore the dynamic viscoelasticity difference of unpolymerized light.cured composite resins with retentive filler or normal filler,and to investigate effect on the clinical manipulation properties of rheological behaviors in two light-cured composite resins to define an ideal resin.DESIGN,TIME AND SETTING:This controlled study is a correlation study of integrating the base study and clinical use.Basic study was performed in January 2003 at Key Laboratory of Engineering Plastics of Chinese Academy of Sciences in Beijing.The clinical observation study was conducted at the Stomatology Center,Haikou People's Hospital until December 2006.MATERIALS:Light-cured composites employed in this study were reinforced with RF(experimental composite resin I,ECR-Ⅰ)or NF(experimental composite resin Ⅱ,ECR-Ⅱ),which were supplied by Dental Materials Laboratory.Medical College of Stomatology of Peking University.They contained different types of fillers,but had the same resin matrix and volume percent of filler.METHODS:The dynamic viscoelastic properties of ECR-Ⅰ or ECR-Ⅱ were measured respectively with the dynamic stress rheometer DSR-200 in a room maintained 25℃.Flowing property,filling capacity,shaping and stability property were employed to assess the clinical manipulation property of ECR.MAIN OUTCOME MEASURES:Viscoelasticity(G',G",tan δ)and clinical manipulation of two kinds of compound resins.RESULTS:The dynamic viscoelastic behavior of the two composites was sensitive to changes in frequency.ECR-Ⅰhad significantly higher G'than ECR-Ⅱ.ECR-Ⅰ had a greater ability of stability and shaping.and a lower potential for deformation clinically.ECR-Ⅱ had significantly higher G"than ECR-Ⅰ.and ECR-Ⅱ had a higher flowing ability clinically.ECR-Ⅱ had significantly higher tan δ than ECR-Ⅰ.ECR-Ⅱ was found to be more viscous and better filling capacity,with a good adaptation to the cavity of the tooth clinically.CONCLUSION:The dynamic viscoelasticity(G',G",tan δ)and clinical manipulation properties of ECR-ⅠI or ECR-Ⅱ are compared.The ideal composites should have higher G'and lower tan δ

Objective To explore the influential facts of betel quid chewing for patients with oral submucous fibrosis (OSF) in Haikou,Hainan Province.Methods One hundred and twenty three patients in the Haikou City People's hospital were investigated regarding their clinical information,including age,sex,origins,kinds and time of betel nut chewing,obvious clinical features,cognition for its harmfulness and so on.Results (1)The mean age was 36.5 years old,the most common patients were the group between the ages of 30 and 50 among 123 patients,male preferred to chewing betel nut,the female fond of betel nut were mostly Li minority women.(2)People chewing the dry betel nut had the higher incidence than the ones who prefer the fresh in five years.The both were significant difference (x2 =18.79,P ＜0.01),however,the incidence difference between the patients at the same time and the ones chewing kinds of betel nut was not significant (P ＞ 0.05).(3)The early clinical features of some OSF patients included stimulating pain,mucosal blanching,gradual inability to open the mouth and fibrous bands.(4)Although 61 patients (49.59％) knew about the harmfulness of betel nut chewing for their oral health,they could not change their lifestyle.Conclusions Male prefers to chewing betel nut,the female fond of betel nut are mostly Li minority women in Haikou area,the parts of patients could not overcome the habit ofchewing betel nut; people chewing the dry betel nut has the higher incidence than the ones who prefer the fresh's at early period,and of the two the former prone to disease than the latter.

OBJECTIVE: To explore the effect of Radii barrier sleeves on the cure depth of composite resin. METHODS: Cylinder mold was prepared, and the resin was filled strictly into the mold. The surface was flattened and then cured with plastic engraver's knife.The depth of composite resin which was cured by QHL75TM with or without Radii barrier sleeves was compared. RESULTS: The cure depth of composite resin which were cured by QHL75TM with or without Radii barrier sleeves of photo-curing machine was 4.38 mm and 4.27 mm respectively,with no statistical difference. CONCLUSION The cure depth of composite resin is not influenced by Radii barrier sleeves under the same light condition.
Composite Resins ; chemistry ; Cross Infection ; prevention & control ; Curing Lights, Dental ; Dental Equipment ; Disposable Equipment ; Equipment Contamination ; prevention & control ; Humans ; Light-Curing of Dental Adhesives ; instrumentation ; methods ; Technology, Dental ; instrumentation

Objective: To study the vascularization of the collagen-binding basic fibroblast growth factor (bFGF)-loaded collagen membranes in soft tissue repair in the hard palates of rats. Methods: Ninety-six male 6-week-old Wistar rats were randomly divided into 4 groups, and 3-mm-diameter circular soft tissue defects were produced from the distal surface of the third molar to the mesial surface of the first molar in their hard palates. The defects were covered with a collagen-targeting bFGF/collagen membrane, a free bFGF/collagen membrane, a collagen membrane or no membrane (control group). Every 6th rat was randomly sacrificed at 1, 2, 4 and 8 weeks in every group after surgery. Wound healing and the number of new blood vessels were measured by hematoxylin-eosin (HE) staining. Results : The numbers of new blood vessels in the collagen-targeting bFGF/collagen membrane group were 8.94 ± 0.61, 17.39 ± 2.08 and 11.22 ± 1.66 at 1, 2 and 4 weeks after surgery, respectively, which were significantly greater than the values in the other groups (P<0.05). At 8 weeks, the number of new blood vessels in the collagen-targeting bFGF/collagen membrane group was 4.17 ± 1.28, and there was no significant difference in the numbers of new blood vessels between any of the groups (P > 0.05). Conclusion Collagen-targeting bFGF/collagen membranes had a favorable effect on promoting angiogenesis during wound healing, and promoted wound healing.

In unicompartmental replacement surgery, there are a wide variety of commercially available unicompartmental prostheses, and the consistency of the contact surface between the common liner and the femoral prosthesis could impact the stress distribution in the knee after replacement in different ways. Medial tibial plateau fracture and liner dislocation are two common forms of failure after unicompartmental replacement. One of the reasons is the mismatch in the mounting position of the unicompartmental prosthesis in the knee joint, which may lead to failure. Therefore, this paper focuses on the influence of the shape of the contact surface between the liner and the femoral prosthesis and the mounting position of the unicompartmental prosthesis on the stress distribution in the knee joint after replacement. Firstly, a finite element model of the normal human knee joint was established, and the validity of the model was verified by both stress and displacement. Secondly, two different shapes of padded knee prosthesis models (type A and type B) were developed to simulate and analyze the stress distribution in the knee joint under single-leg stance with five internal or external rotation mounting positions of the two pads. The results showed that under a 1 kN axial load, the peak contact pressure of the liner, the peak ACL equivalent force, and the peak contact pressure of the lateral meniscus were smaller for type A than for type B. The liner displacement, peak contact pressure of the liner, peak tibial equivalent force, and peak ACL equivalent force were the smallest for type A at 3° of internal rotation in all five internal or external rotation mounting positions. For unicompartmental replacement, it is recommended that the choice of type A or type B liner for prosthetic internal rotation up to 6° should be combined with other factors of the patient for comprehensive analysis. In conclusion, the results of this paper may reduce the risk of liner dislocation and medial tibial plateau fracture after unicompartmental replacement, providing a biomechanical reference for unicompartmental prosthesis design.
Arthroplasty, Replacement, Knee/methods* ; Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Knee Joint/surgery* ; Knee Prosthesis ; Tibia/surgery*

Objective: To evaluate the clinical effectiveness of salvianolic acid B (SA-B) and triamcinolone acetonide (TA) by means of combined intralesional injection in the treatment of oral submucous fibrosis (OSF). Methods: According to clinical findings and symptoms, TA combined with SA-B were consecutively applied intralesionally 1 time weekly for 30 times. Mouth opening degree, color change of the buccal mucosae and numeral increase of the capillary vessels were determined by degree Ⅰ-Ⅳ visual analog scale were evaluated at 12, 24, and 36 months, respectively. Results: One hundred and fourteen subjects fulfilled the study without obvious adverse reactions. After treatment for 1 year, the net gain in mouth opening of the early stage group was (5.5 ± 1.5) mm at 12 months, (8.8 ± 1.6) mm at 24 months and (12.0±1.2) mm at 36 months. The net gain in mouth opening of the middle stage group were (5.3±1.7) mm at 12 months, (10.5±1.5) mm at 24 months and (14.5±2.4) mm at 36 months. The net gain in mouth opening of the advanced stage group were (5.7±1.3) mm at 12 months, (13.7±1.3) mm at 24 months and (15.5±1.5) mm at 36 months. The effective rates of color change of the buccal mucosae and numeral increase of the capillary vessels after treatment for 36 months were 100% in early stage group, 93% (51/55) in middle stage group and 90% (36/40) in advanced stage group. Conclusions TA and SA-B combined intralesional injection in the treatment of oral submucous fibrosis is effective.

OBJECTIVE: To observe the clinical effect on site preservation with self platelet-rich fibrin (PRF) in posterior dental areas after extraction.
 METHODS: Thirty patients who asked to extract posterior teeth and were ready for dental implantation were enrolled. PRF was implanted immediately in alveolar fossa after extraction. Cone beam computer tomography (CBCT) images were taken after 4-6 months and the changes in height and width of alveolar bone were observed.
 RESULTS: There was no statistical difference in the height and width between the alveolar bone treated with PRF after the extraction of tooth and the bone condition before the extraction of tooth.
 CONCLUSION The site preservative technology with PRF could maintain the mass of alveolar bone in posterior dental areas, which provide a better bone condition for later dental implantation.
Alveolar Process ; Blood Platelets ; Cone-Beam Computed Tomography ; Dental Implantation ; Fibrin ; therapeutic use ; Humans ; Tooth Extraction