The relationship between arch width and vertical facial skeletal types of the adults with individual normal occlusion / 实用口腔医学杂志

Objective:To analyze the correlation between arch width and different vertical facial skeletal types of the adults with individual normal occlusion.Methods:52 adults with individual normal occlusions(females 31,males 21) were included.According to the values of mandibular plane angle MP-FH,SN-MP measured on CBCT image the subjects were divided into 3 groups(13 cases with highangle,19 with average-angle and 20 with low-angle groups).12 parameters were measured for each sample,including maxillary and mandible arch width and alveolar arch width between canines,between first premolars and between first molars,the difference between the maxillary arch width and mandibular arch width were calculated.The data were statistically analyzed by one-way ANOVA and Pearson~ rank correlation test.Results:In the group of high-angle,average-angle and low-angle the alveolar arch width(mm) between maxillary canines was 38.03 ± 1.90,39.65 ± 1.80 and 39.78 ± 2.20 respectively(P ＜ 0.05).The arch width between maxillary first premolars of high-angle group(37.01 ± 1.60) was smaller than that of low-angle group(38.65 ± 1.30).The arch width difference in canine area between maxillary and mandibular alveolar in high-angle,average-angle and low-angle groups was 7.39 ± 1.82,9.04 ± 1.43 and 9.26 ± 1.67 respectively(P ＜0.05);in maxillary first premolars area in high-angle(6.8 ± 1.59) was smaller than that in averageangle(7.79 ± 1.09),maxillary and mandibular arch width showed no statistical difference.Pearson correlation test showed that among 3 groups,upper and lower alveolar arch width difference in canine and first premolars area was negatively correlated with the mandibular plane angle.while upper and lower arch width difference showed no statistical correlation with the mandibular plane angle.Conclusion:The maxillary middle arch width of the subjects with individual normal occlusion was correlated with vertical facial type.

Prefabrication of Axially Vascularized Bone by Combining β-Tricalciumphosphate, Arteriovenous Loop, and Cell Sheet Technique

The repair of bone defects poses a great challenge for reconstructive surgeons. Although the development of tissue engineering has exhibited promise in replacing damaged bone, the fabrication of large constructs with functional blood vessels remains an obstacle. From the orthopedic surgeon's point of view, the generation of axially vascularized bone, which can anastomose with the recipient vessel, might be a solution to this medical problem. In this study, we aimed to prefabricate an axially vascularized bone by combining a β-TCP scaffold, arteriovenous loop (AVL), and cell sheet in a bioreactor in vivo. Twelve rabbits were randomly allocated into two groups: the experimental group (presence of AVL) and the control group (absence of AVL). The constructs were explanted at 8 weeks postoperatively. The histomorphometric results showed 42.8±5.9% of the bone area in the AVL group and 26.6±3.5% in the control group. Similarly, vessel analysis revealed the average vessel density in the AVL group (12.5±3.3) was significantly more than that in the control group (6.1±1.5, p<0.05). Our research indicated that the combination of a β-TCP scaffold, AVL and cell sheet might engineer vascularized bone. This prefabrication strategy might facilitate clinical translation of bone tissue engineering in reconstructing large bone defects.

Three-dimensional Culture of Chondrocyte Using Methacrylic Alginate Gel Beads Cross-linked with Mixed Metal-cation / 生物医学工程学杂志

This study was to explore a better three-dimensional (3-D) culture method of chondrocyte. The interpenetrating network (IPN) gel beads were developed through a photo-cross linking reaction with mixed barium ions and calcium ions at the ratio of 5:5 with the methacrylic alginate (MA), which was a chemically conjugated alginate with methacrylic groups. The second generation of primary cartilage cells was encapsulated in the MA gel beads for three weeks. In the designated timing, HE stain, Alamar blue method and Scanning electron microscopic were used to determine the cartilage cells growth, proliferation and the cell distribution in the scaffolds, respectively. The expression of type II collagen was investigated by an immunohistochemistry assay and the glycosaminoglycan content was quantitatively evaluated with the spectrophotometry of 1, 9 dimethylene blue assay. Compared to the alginate control group, the deposition of glycosaminoglycan was significantly upregulated in IPN-MA gel beads with higher cell proliferation. The secretion of extracellular matrix and proliferation of chondrocyte in methacrylic alginate gel beads were higher than that in Alginate beads. Cells were able to attach, to grow well on the scaffolds under scanning electron microscopy. The result of immunohistochemistry staining of collagen type II was positive, confirming the maintenance of chondrocyte phenotype in methacrylic alginate gel beads. This study shows a great potential for three-dimensional culture of cartilage.

The effect of tooth extraction and nonextraction treatment on the soft tissue profile of the subjects with border-line Angle classⅡ division 1 malocclusion / 实用口腔医学杂志

The effect of extraction and nonextraction treatment on the soft tissue profile of the subjects borderline Angle classⅡ division 1 malocclusion is concerned mainly by orthodontists.This article reviewes the effect of extraction and nonextraction treatment on the soft tissue profile of the subjects with Angle classⅡ division 1 borderline patients and the important factors(such as differences between the types of tooth extraction and growth).The aim is to guide clinic diagnosis and treatment for borderline Angle classⅡ division 1 malocclusion.

Research progress of cell sheet technology and its applications in tissue engineering and regenerative medicine / 生物医学工程学杂志

Cell sheet engineering is an important technology to harvest the cultured cells in the form of confluent monolayers using a continuous culture method and a physical approach. Avoiding the use of enzymes, expended cells can be harvested together with endogenous extracellular matrix, cell-matrix contacts, and cell-cell contacts. With high efficiency of cell loading ability and without using exogenous scaffolds, cell sheet engineering has several advantages over traditional tissue engineering methods. In this article, we give an overview on cell sheet technology about its applications in the filed of tissue regeneration, including the construction of soft tissues (corneal, mucous membrane, myocardium, blood vessel, pancreas islet, liver, bladder and skin) and hard tissues (bone, cartilage and tooth root). This techonoly is promising to provide a novel strategy for the development of tissue engineering and regenerative medicine. And further works should be carried out on the operability of this technology and its feasibility to construct thick tissues.

Preparation and properties evaluation of methacrylic alginate gell beads cross-linked by mixed metal-cation / 生物医学工程学杂志

The aim of this study was to obtain the alginate gels which could have proper compressive strength and excellent permeability for cell proliferation and could have more promising potentials in the application of tissue engineering. Through the reaction of the carboxyl of the alginate and the amino of methacrylic acid, methylacrylic was generated into alginate long chain which could be enhanced by the polymerization of double bond under thermal reaction condition. And then alginate gel beads were prepared using the mixture of calcium chloride and barium chloride solution as cationic crosslinker, and the compressive modulus and permeability of the prepared alginate gel beads were investigated. When the ratio of barium ions to calcium ions was 5:5, the compression modulus was 189.7 kPa, and it showed the best permeability for trypsin with molecular weight of 24 kDa and entrapment effect for bovine serum albumin with molecular weight of 67 kDa. Compared to compositions of other ratios, the alginate gel beads made in 5:5 mixture indicated excellent compressive modulus and permeability. These results indicated that the alginate hydrogel beads with the ratio of barium ions to calcium ions being 5:5 have a potential application in tissue engineering as a support material and encapsulating materials in cell culture.

Mechanical properties of alginate hydrogels with different concentrations and their effects on the proliferation chondrocytes in vitro / 生物医学工程学杂志

The mechanical properties of natural and synthetic extracellular matrices affect cellular processes and regulate tissue formation. In order to explore the optimal environment for chondrocytes growth in vitro, we investigated the relationship between the mechanical properties of the alginate beads and the ability of chondrocyte proliferation in this study. We measured the compressive properties of alginate with different concentrations by INSTRON 3365,and found that compressive moduli significantly increased with increasing alginate concentration. The rabbit chondrocytes were encapsulated in 1%, 2% and 3% (w/v) alginate beads at high (1 x 10(7)/ml) density. After 4 week's culturing, all the three groups resulted in the limited proliferation of the chondrocytes and the formation of cell clusters resembling cartilaginous tissues. Chondrocytes proliferation was more rapid on lower concentrate gels (1%, 2%) than on the higher concentrate gels (3%). These results suggested that the mechanical properties of scaffold architecture had certain effect on chondrocytes proliferation.

Study of the tracings of the condylar movements during opening/closing of the unilateral posterior crossbite / 西安交通大学学报(医学版)

Objective To discuss the influence of dental occlusion on mandibular movements. The characteristic tracings of mandibular movements at the condyle of unilateral posterior crossbite patients were investigated using a computerized axiography. The differences between patients with normal occlusion and unilateral posterior crossbite were compared by some recordings of condylar movements in three dimensions. Methods Seven unilateral posterior crossbite patients (at least two posterior teeth were crossbite) were chosen as experiment group, and five with normal occlusion without signs or symptoms of temporomandibular disorders (TMD) were chosen as controls. By computer-aided axiography (CADIAX) and gamma dental software for windows 2.3.2.22 (GDSW) from Grbh company (Germany), the tracings of condylar movements in right and left parasagittal planes during opening/closing were recorded, and the data were input into the computer and analyzed using GDSW software. The drifts in X, Y and Z coordinated with condylar movements, respectively, and the transverse condylar inclination from the orbital axis line and the horizontal condylar inclination were calculated, respectively. Results The lengths of the axiographical in opening/closing movement were significantly shorter in the experiment group than that in normal occlusion group; the bilateral condylar tracing of opening/closing movement was symmetric in younger cases but asymmetric in older cases; the lateral deviation of opening/closing movement was significantly larger in unilateral posterior crossbite than that in control group. Conclusion The condylar tracings of envelope of movement in unilateral posterior crossbite patients are significantly different in the patients with normal occlusion. With age increasing, tracings of the affected side and contralateral side vary from symmetry to asymmetry. The results suggest that the functional opening movements are limited in the patients with the unilateral posterior crossbite.