A comparison of the fracture resistances of endodontically treated mandibular premolars restored with endocrowns and glass fiber post-core retained conventional crowns

PURPOSE: This in-vitro study aimed to evaluate the fracture resistances and failure modes of endodontically treated mandibular premolars restored with endocrowns and conventional post-core retained crowns. MATERIALS AND METHODS: Thirty mandibular premolars were assigned into three groups (n=10): GI, intact teeth; GE, teeth with endocrowns; GC, teeth with conventional post-core supported crowns. Except for the teeth in group GI, all specimens were cut to 1.5 mm above the cementoenamel junction and endodontically treated. Both endocrowns and conventional crowns were fabricated from lithium-disilicate blocks using a CEREC 3D CAD/CAM unit. All specimens were subjected to thermocycling and then to 45° oblique compressive load until fracture occurred. The fracture resistance and failure mode of each specimen were recorded. Data were analyzed with one-way ANOVA and LSD Post Hoc Test (α=.05). RESULTS: The fracture resistances of GE and GC were significantly lower than that of GI (P<.01), while no significant difference was found between GE and GC (P=.702). As of the failure mode, most of the specimens in GE and GC were unfavorable while a higher occurrence of favorable failure mode was presented in GI. CONCLUSION: For the restoration of mandibular premolar, endocrown shows no advantage in fracture resistance when compared with the conventional method. Both of the two methods cannot rehabilitate endodontically treated teeth with the same fracture resistances that intact mandibular premolars have.

Study on correlations between CT perfusion parameters and tumor angiogenesis of cervical cancer / 生物医学工程学杂志

This study was aimed to analyze the correlation between CT perfusion parameters, e. g. perfusion (PF), blood volume (BV), peak enhancement image (PEI), time to peak (TTP), and the microvessel density (MVD) of cervical cancer. CT perfusion scans were carried out in 31 patients with cervical cancer. After their surgical resections, we obtained 31 cases of cervical cancer specimens, and 15 cases of adjacent normal cervical specimens as control group, then these 46 specimens were used in MVD detection through immunohistochemical CD34 staining. The MVDs of the tumor group were significantly higher than those in the control group, and the former seems to increase with the clinical stages with a positive correlation. The PF and PEI values have positive correlations with corresponding MVD values. The PF value of squamous carcinoma group has correlation with corresponding MVD value. The PF and PEI values of poorly differentiated group have correlations with corresponding MVD values. The PF, PEI and BV values of II-III stage group are positively correlated with corresponding MVD values. The PF value of lymph metastasis or non-lymph metastasis group both have correlations with corresponding MVD values. We found that CT perfusion parameters were positively correlated with corresponding MVD values in cervical cancer. Our results suggest that CT perfusion is a new method which could reflect tumor angiogenesis, histological malignant grade, invasion, and clinical stage. It will help us determine the tumor staging and prognosis.

The Affection on Cochlea Function of Guinea-pig by Transplanting Controlled Release BMP-2 into the Middle Ear / 听力学及言语疾病杂志

Objective The controlled release BMP-2 and implantation into the acoustic bulla of the guineapig and the effects on the cochlea were observed.Methods The acellular cancellous bone was prepared,accompanied with BMP-2.The material accompanied with BMP-2 was implanted into one acoustic bulla of the animal,and the opposite side of the acoustic bulla was implanted with acellular cancellous bone without BMP-2.A total of 20 guinea-pigs were undergone this procedure.The ABR was tested on the animals before and after the operation immediately and 3 month after operation,respectively.3 month after operation,the animals were sacrificed.The osteogenesis induced by BMP-2,the acoustic bulla and the cochlea affected by BMP-2 were observed.The structures of hair cells were observed after being treated with silver nitrate.Results The animals recovered soon after surgery.The hearing thresholds of the animals reduced slightly after the operation,and recovered completely 3 month after.The bulla and the cochlea were normal in shape.The osteogenesis occurred in the pore of the acellular cancellous bone with BMP-2.No abnormal hyperplasia of bone in the hulla and the cochlea was found.The articulation between the stapes and oval window was not merged.The shape of the hair cells was normal and no obvious deletion of the hair cells was noted when compared with control group.Conclusion The controlled release BMP-2 could induce osteogenesis in the bulla of the animals.This material did not affect the shape of the bulla and the hearing thresholds.They did not induce any abnormal hyperplasia of bone in the bulla and might be used to reconstruct the affected ossicles.

Possibility of the acellular bony microtubule used to construct tissue engineering ossicular prosthesis / 中国耳鼻咽喉头颈外科

OBJECTIVE To study the possibility of acellular bony microtubule used to construct tissue engineering ossicular prosthesis. METHODS To prepare the acellular bony microtubule, observe the change of its histocompatibility and biomechanics. The acellular bony microtubule carried with collagen/ BMP-2 was implanted into the middle ear of the animals. The ectopic osteogenesis was observed. RESULTS The acellular bony microtubule has good histocompatibility. There wasn’t significant change about biomechanics. After carried with collagen/BMP-2, the bony microtubule can induce osteogenesis in the animal’s middle ear. CONCLUSION The acellular bony microtubule carried with collagen/BMP-2 has the possibility to be used to construct tissue engineering ossicular prosthesis.

Wireless real-time monitoring system for body temperature / 医疗卫生装备

The wireless real-time monitoring system for body temperature is based on electronic thermometry and wireless communication technology. It can measure and store the patient's body temperature during the desired time span, and can transmit the data to the computer terminal or the cell phone terminal through wireless transmission system.

A study on biological characteristics of normal adult human nasal septal chondrocytes cultured in vitro / 临床耳鼻咽喉头颈外科杂志

Objective:To study the characteristics of normal adult human nasal chondrocytes cultured in vit-ro. Method :The adult human nasal septal chondrocytes were cultured in vitro. The changes of cellular morpholo-gy from primary to subculture were investigated ;to observe the proliferation of chondrocytes by the growth curveand the survive rate of chondrocytes;and to determine the biologic synthesis of the chondrocytes by toluidineblue,alkaline phosphatase staining and type Ⅱ collagen immunohistochemistry reaction. The survive rate of thenasal septal chondrocytes was observed after being frozen (－196C). Result: The morphology of the primarychondrocytes maintained the spherical shape ,and some became polygonal shape after 4 days. Most of the chondro-cytes transformed into the shape of the fibroblast cell since the fifth generation. The number of the chondrocytes(2th generation)after being cultured in vitro for 5 days was approximately 4 fold of that of the plating. The phe-notype of the chondrocytes was maintained in the first 4 generation,the survive rate of the chondrocytes suscitat-ing from being frozen (－196C ) was 93 %. Conclusion:The normal adult nasal septal chondrocytes cultured inmonolayer in vitro maintained the specific chondrocytes phenotype in the first 4 generation,the growth was nor-mal ,and could survive in the condition of deep-frozen.