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Development in Ceramic Veneer Restorations CHEN Xiao-dong, XING Wen-zhong 2018, 34(8): 805-808.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.001 Abstract ( 464 )   PDF (939KB) ( 687 )   Ceramic veneer has become a widely used aesthetic restorative method due to its more conservative preparations and superior optical property and esthetics. With the development of ceramic property, manufacturing technique and bonding systems, ceramic veneer has greatly increased the long-term success rate. This paper reviewed the indication of ceramic veneer, tooth preparation, manufacturing technique, esthetic effect, and clinical prognosis. References | Related Articles | Metrics

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Application of Nanofibrous Scaffold in Bone Tissue Engineering HUANG Shan, LIU Hong 2018, 34(8): 809-811.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.002 Abstract ( 306 )   PDF (810KB) ( 384 )   Nanofibrous scaffolds, which are porous and hierarchical, have been widely used in bone tissue engineering in recent years. Bone tissue engineering consists of three parts: suitable seed cells, scaffolds, and growth factors. The research on bone tissue engineering focused on finding three-dimensional tissue engineering scaffolds to promote cell growth and guide bone regeneration. Since nanofibrous scaffolds, which are similar to the extracelluar matrix of natural bone in morphology and structure, can promote cell adhesion and stem cell differentiation, they have become ideal scaffolds in bone regeneration in recent years. In this paper, we review the fabrication technologies of nanofibrous scaffolds and their advanced applications. References | Related Articles | Metrics

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Research Progress on Clinical Application of Single Implant Restoration with Different Crown-to-implant Ratios WEI Song-guan, LIAO Hong-bing 2018, 34(8): 812-814.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.003 Abstract ( 361 )   PDF (944KB) ( 297 )   Theory of crown to root ratio has an important reference value for natural teeth to assess its prognosis. However, a large number of animal experiments and clinical practice proved that it may not suit to implant. With the wide application of short implants, the correlation between different crown-root ratios of implants and implantation success rates, marginal bone resorption, and mechanical complications of implants has drawn the attention of many clinicians and scholars. This article discusses these aspects one by one. References | Related Articles | Metrics

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Research Progress of Stress Response-related Two Component Signal Transduction Systems of Streptococcus Mutans ZHAO Xin-yuan, CUI Li 2018, 34(8): 815-817.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.004 Abstract ( 263 )   PDF (813KB) ( 295 )   Streptococcus mutans (S. mutans) is considered one of the primary etiological agents of dental caries. The two component signal transduction pathways network of S. mutans is comprised of histidine protein kinase and response regulator protein. Two component systems (TCSs) enable S. mutans to sense the environments changes and regulate the expression of important genes, which are essential for the survival and virulence adjustment of S. mutans. This article comprehensively reviews the current progress of the TCSs systems closely associated with stress response of S. mutans. References | Related Articles | Metrics

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Bisphosphonate Leads to Osteonecrosis of Jaw: A Review of Mechanism SUN Jin, ZHANG Qiang 2018, 34(8): 818-820.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.005 Abstract ( 281 )   PDF (809KB) ( 282 )   Bisphosphonate is a group of drugs commonly used for the treatment of osteoporosis and tumors. The complication of bisphosphonate is osteonecrosis of the jaw. The clinical manifestation and incidence of bisphosphonate are fully reported at present. However, the pathogenesis and mechanism are still remaining insufficient. References | Related Articles | Metrics

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Design and Application of Modified Appliance for Posterior Crossbite WU Di, LU Jing, WANG Jiao-jiao, WANG Sheng-guo 2018, 34(8): 821-823.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.006 Abstract ( 282 )   PDF (1162KB) ( 331 )   The posterior crossbite is a common malocclusion characterized by abnormal buccal/lingual relationship between the maxillary and mandibular posterior teeth,which seriously affected the oclussal function, aesthetics, and oral health. There are multiple clinical manifestations, considering the distribution of medical resources, the orthodontist's technical level, and patient's wishes. It is hard to say that a correction method is perfectly suitable for a certain case. After fully understanding the malocclusion causes,orthodontists should select, improve, or design a more fast, effective, safe, and comfortable method according to specific circumstances. This paper provides an overview of posterior crossbite about etiology, clinical harm, the shortcomings of traditional clinical treatment methods, principles of improvement or design, and the prevention and treatment of possible problems in the process. And the application of three improved new appliances is introduced, which will provide reference for clinical practical treatment of posterior crossbite. References | Related Articles | Metrics

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Preliminary Application of DIAGNOcam for Clinical Practice WANG Fei, SU Chao-nan, ZHENG Shu-ning, BIAN Zhuan, MENG Liu-yan 2018, 34(8): 824-827.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.007 Abstract ( 320 )   PDF (2117KB) ( 237 )   Objective: To analyze the imaging characteristics of proximal and occlusal carious lesions with DIAGNOcam system (DC), and to evaluate its ability to diagnose proximal and occlusal caries. Methods: Sixty adults with complete permanent dentition were included. They were examined by visual inspection using international caries detection and assessment system (ICDAS) and DC, and if necessary, bitewing radiographs (BW). Finally 547 teeth were examined by all three methods. Seventy-eight proximal dental carious lesions were treated operatively and the corrrelation of the examination methods were analyzed. Results: ICDAS scores (1-4) of pit and fissure caries were consistent with the extent of shadows on DC image. On the level of dentin caries, the similarity ratio of the detection rate of DC and BW was 93.59%, and the diagnostic accuracy of DC was 100%. Conclusion: DC is an effective examination method to assist the diagnosis of dental caries. References | Related Articles | Metrics

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Nanogels of Carboxymethyl Chitosan and Lysozyme Encapsulated Amorphous Calcium Phosphate to Promote the Remineralization of Demineralized Enamel SONG Jin-hua, LIU Zong-ren, LIU Wen-chao, ZHANG Xu, LI Yan-qiu 2018, 34(8): 828-831.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.008 Abstract ( 275 )   PDF (2613KB) ( 288 )   Objective: To stabilize amorphous calcium phosphate (ACP) and further promote the remineralization of demineralized enamel by preparation of carboxymethyl chitosan (CMC)-lysozyme (LYZ) gel. Methods: Firstly, CMC/LYZ-ACP nanogels were prepared. The morphology was characterized by transmission electron microscopy (TEM). Distribution and quantity of elements in CMC/LYZ-ACP nanogels were determined by element mapping and energy dispersive X-Ray spectroscopy (EDX). Then, the nanogel was applied to the surface of the etched enamel. Scanning electron microscopy (SEM) images and nanoindentation were applied to check the efficacy of remineralization. The result was compared with the artificial saliva group. Result: The CMC/LYZ-ACP nanogels were dense spherical particles with the particle size approximately 50-300 nm. SEM images showed that there were new crystals formed on the enamel surface after demineralization. Compared with the control group, the hardness and elastic modulus of the experimental group were closer to the normal enamel. Conclusion: CMC/LYZ-ACP nanogels are novel biomimetic materials that can be used for remineralization of demineralized enamel. References | Related Articles | Metrics

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Preliminary Study on Diagnosis of Cracked Teeth Assisted by Laser Fluorescence CHEN Gong-pei, YU Qing, YANG Wei-dong, YANG Ya-ping, HUA Fang 2018, 34(8): 832-835.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.009 Abstract ( 239 )   PDF (1136KB) ( 170 )   Objective: To investigate the effectiveness of laser fluorescence on the diagnosis of cracked teeth, and to explore new techniques for the diagnosis of cracked teeth. Methods: Thirty-seven cracked teeth diagnosed by means of bite tests and microscopic detection were included in this experiment. DIAGNOdent 2190 was used to detect these cracked teeth, and the fluorescence was recorded. The control teeth were detected by the same method. Results: There was a significant difference on the fluorescence between the cracked teeth and the control teeth (P<0.001). The fluorescence values of the cracked teeth were all within the range of early caries. Conclusion: Laser fluorescence can be used to diagnose the cracked teeth. There are varying degrees of early caries in the cracks, and fluorescence can be used to develop treatment plans and assess prognosis. References | Related Articles | Metrics

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Effect of Apical Foramen Sizes on Dental Pulp Tissue Regeneration and Teeth Compressive Strength LI Jing, KONG Li-Xin, SHEN Shuai, WANG Lu-Yao, NIU Yu-Mei, PAN Shuang 2018, 34(8): 836-840.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.010 Abstract ( 239 )   PDF (1953KB) ( 275 )   Objective: To investigate the effect of apical foramen sizes on pulp tissue regeneration and teeth compressive strength. Methods: Single root premolars with complete root development and without tooth root fracture were collected after orthodontic extraction. Twelve millimeter tooth roots were preserved after de-crowned, and randomly divided into 5 groups with 25 teeth in each group. The root canals were prepared to 30#, 40#, 60#, 80#, and 100# main files, respectively, in which 30# main file group was used as the control group. Human dental pulp stem cells were cultured in vitro and inoculated into 0.25% hydrogel scaffolds and then injected into the root canals of different groups. Five teeth were taken from each group and were cultured in Transwell chamber for 14 days, 21 days, and 28 days. Then, the total RNA of the cells was extracted, the expression of DSPP and DMP 1 were detected by real-time PCR. The remaining 10 teeth in each group were implanted subcutaneously into the nude mice. After 28 days, 5 teeth were used for histological examination and 5 samples were used for static load test. Results: After 28 days, the expression of DSPP and DMP1 in the experimental groups were higher than those in the control group (P<0.05), and the expression of 40 # main file group was higher than that in the experimental groups (P<0.05). Histological analysis showed that there was no continuous pulp like tissue formation in the 30#, 40#, and 60# main file groups. The tissue formation in the 80 # and 100 # main file group could be seen, but no typical pulp like tissue structure was found. The static load test showed that the average compressive load of 40 # main file group was not different from that of the control group, while the other experimental groups were lower than the control group (P<0.05). Conclusion: The size of apical foramen has no significant effect on pulp tissue regeneration within size of 100# (1 mm), but the compressive strength of apical foramen is obviously decreased when the apical foramen is prepared more than 40#. References | Related Articles | Metrics

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Evaluation on Refractive Index of Caries-affected Dentin: An In Vitro Study DING Jiang-feng, GAO Qing-feng, LU Min-hua 2018, 34(8): 841-845.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.011 Abstract ( 190 )   PDF (2676KB) ( 262 )   Objective: To analyze the variation of refractive index (RI) of caries-affected dentin by using OCT. Methods: Nineteen extracted third molars were selected, and four of which were caries free and other fifteen had occlusal dentin caries. The dentin slices with thickness ranging from 300 to 500μm were prepared perpendicular to long axis of the tooth crown for all teeth. Ten slices from caries free teeth were chosen as the control group. Fifteen slices were chosen as the study group. All dentin slices were scanned by micro-CT and a self-built OCT system (Dental 1.0, demo), and reconstructed to be three-dimensional digital slices. The RI of the caries-free and caries-affected dentin slices were calculated by optical path length-matching method basing on an improved canny edge detection algorithm. The mineral density (MD) of the caries-affected dentin slices was evaluated by comparing the grayscale difference between the slice and the calibration phantom using K2HPO4 liquids. Results: ith an increase of the distance from the reference center to enamel-dentin junction (EDJ), the RI of caries-free dentin increased firstly and then decrease, while that of caries-affected dentin is less affected. The mean value of RI of the caries-free dentin was 1.578, which was significantly higher than that of the caries-affected dentin (P<0.001). A good linear correlation was found between the RI and MD (Pearson's r=0.78) in the caries-affected dentin (P<0.001). Conclusion: Caries would lead to variation of refractive index of dentin. The mineral density was an important factor causing the decrease of dentin refractive index. References | Related Articles | Metrics

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Diversity and Community Structure of Subgingival Bacterial from Patients with Moderate or Severe Periodontitis FAN Hua-nan, HUANG Hui, JIANG Qing-kun, LIU Yi 2018, 34(8): 846-851.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.012 Abstract ( 241 )   PDF (3025KB) ( 260 )   Objectve: To investigate and compare the oral microbial community from patients suffering severe and mild periodontitis by using high throughput sequencing of 16s rDNA genes. Methods: Seventy patients with moderate or severe periodontitis were selected as the subjects. According to their symptoms, they were divided into SP (severe periodontitis, 9 cases) group and MP (moderate periodontitis, 8 cases) group. The subgingival bacteria of the patients were sequenced with 16s rDNA. Then the OUT(operational taxonomic units)abundance of each sample and the classification of each level (domain, boundary, gate, class, order, family, genus, and species) were counted and analyzed with α and β diversity. Finally, the data of 16S rRNA for each sample were analyzed and the function of bacteria was predicted. Results: The high quality sequence (555028) obtained from subgingival samples (555028) was divided into OTUs, representing 303 independent species, belonging to 138 genera, 75 families, 47 orders, 28 classes and 12 phyla. Two groups shared 332 OTUs, indicating the presence of a core subgingival microbiome. α diversity analysis showed that the microbial diversity in severe periodontitis exceeded that of moderate periodontitis. The dominant phyla of subgingival microbiota included Bacteroidetes, Firmicutes, Fusobacteria, Proteobacteria, and Spirochaetae. The dominant genera included Fusobacterium, Streptococcus, Porphyromonas, Prevotella, Neisseria, and Treponema. β diversity analysis showed that the microbial community structure was similar in two groups. All the samples were predicted 39 kinds of metabolic function, mainly concentrated in the membrane transport (10.9%),replication and repair (9.9%), glucose metabolism (9.3%), amino acid metabolism (9.1%), translation (6.9%), energy metabolism (5.8%), and bad character (5.1%). Conclusion: The subgingival bacteria of periodontitis have rich diversity and stable community structure. The function of subgingival bacteria is the same as the bacteria in other parts of the mouth. The severity of periodontitis is related to the diversity of subgingival bacteria, but not related to the community structure of the bacteria. In view of the microbial diversity and symbiosis of periodontitis, the therapeutic strategies for regulating the interaction and function of microorganism should be further developed. References | Related Articles | Metrics

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Effect of Cetylpyridinium Chloride on Red Complex Bacteria in Moderate to Severe Chronic Periodontitis Patients by Real-time Quantitative PCR YE Xing-ru, XU Yan, PANG Gang, WANG Ying, ZHOU Li-li, JIANG Peng, SHEN Ji-long, WANG Rong-hai 2018, 34(8): 852-856.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.013 Abstract ( 214 )   PDF (1656KB) ( 221 )   Objective: To determine the effect of CPC mouthwash on the proportions of red complex bacteria in patients with moderate to severe chronic periodontitis by RT-qPCR. Methods: Forty patients with periodontitis were randomly assigned to two groups: experimental group (SRP+CPC) and control group (SRP+ placebo). Clinical parameters were recorded at baseline and at 4 weeks. Subgingival plaque, gingival crevicular fluid, and saliva samples were collected, and the content of trypsin-like enzyme was detected using BANA test. RT-qPCR was used to detect the proportions of P.gingivalis, T.forsythia and T.denticola in total bacteria. Results: AL, BOP, and PLI significantly improved (P<0.01) after treatment in the experimental group. Only AL significantly improved in the control group (P<0.01). The level of trypsin-like enzyme in subgingival plaque and gingival crevicular fluid for both groups decreased significantly (P<0.05). The numbers of P. gingivalis decreased significantly in both groups (P<0.01), while T.forsythia decreased significantly in the experimental group (P<0.01). There was no significant difference in the numbers of T.denticola after treatment compared to baseline. There was a significant correlation between the proportions of P.gingivalis, T.forsythia, and T.denticola (P<0.01). Conclusion: CPC can inhibit plaque formation and improve clinical parameters in patients with moderate to severe chronic periodontitis, but has no significant inhibitory effect on P.gingivalis, T.forsythia, and T.denticola. References | Related Articles | Metrics

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Effect of Recombinant Human BMP-9 on Osteogenesis of Human Periodontal Ligament Fibroblasts LU Bei 2018, 34(8): 857-861.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.014 Abstract ( 192 )   PDF (1183KB) ( 188 )   Objective: To investigate the effect of recombinant human BMP-9 (rhBMP-9) on the differentiation of human periodontal ligament fibroblasts into osteoblasts. Methods: Human periodontal ligament fibroblasts were cultured in vitro and osteogenic differentiation was induced by osteogenic differentiation medium (ODM). Then the cells were treated with different concentrations of rhBMP-9 in the presence or absence of p38 and extracellular signal-regulated kinase 1/2 (ERK1/2). Alkaline phosphatase (ALP) activity was measured using LabAssayTM ALP assay kit. The total RNA was extracted and real time fluorescence quantitative (qPCR) was used to detect the expressions of Runt-related transcription factor 2 (RUNX2),inhibitor of differentiation factor 1 (ID1),bone sialoprotein (BSP) and osteopontin (OPN). Results: RhBMP-9 stimulation significantly increased the ALP activity of human periodontal ligament fibroblasts in a concentration and time-dependent manner. Osteogenic differentiation-related transcription factors RUNX2 and ID1, as well as the expression of late osteogenic markers BSP and OPN, were also significantly increased by stimulation with rhBMP-9. Compared with rhBMP-9 alone, the effect of rhBMP-9 on osteogenic differentiation of human periodontal ligament fibroblasts was completely abolished by adding SB203580 and U0126 costimulation. Conclusion: RhBMP-9 could induce the osteogenic differentiation of human periodontal ligament fibroblasts, which might relate to the adjustment of p38 and ERK1/2 pathways. References | Related Articles | Metrics

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Immediate Implantation and Loading for Patients with Severe Periodontitis by All-on-4: A Short-term Clinical Observation WANG Li-li, SONG Hong-guang, SUN Peng 2018, 34(8): 862-865.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.015 Abstract ( 269 )   PDF (1419KB) ( 193 )   Objective: To investigate the clinical results of all-on-4 for edentulous patients caused by severe periodontitis. Methods: Twenty-five patients were performed with all-on-4 at immediate implantation and immediate loading. Plaque index, sulcular bleeding index, and probing depth were measured at 3, 6, and 12 months after permanent restoration. The satisfied degree, masticatory efficiency, and success rate were calculated. Results: Success rate and masticatory efficiency were 99% and 69.97%, respectively at 12 months after permanent restoration. There was no significant difference in plaque index at 3, 6, and 12 months after permanent restoration. Sulcular bleeding index at 12 month was the highest (P＜0.05). Probing depth after 6 months was higher than that after 3 months (P＜0.05). The satisfied degrees for stability and articulation of denture were both 100%, for aesthetics was 92%, for masticatory efficiency was 96%, and for comfortability was 88%. Conclusion: All-on-4 showed good performance in the success rate and masticatory efficiency in short-term. References | Related Articles | Metrics

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Animal Experiment on Cooperation between Shh and IGF-1 in Promoting Mandibular Cartilage Overgrowth CHEN Yu-xiang, HUANG Qun, ZHANG Wu-yang, MA Qin, LONG Xing 2018, 34(8): 866-869.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.016 Abstract ( 221 )   PDF (1687KB) ( 133 )   Objective: To investigate the combination effect of Shh and IGF-1 in promoting the mandible condylar cartilage overgrowth. Methods: Transgenic rats with IGF-1-over expression in condylar cartilage were constructed to allow the local administration of IGF-1 and its specific inhibitor NVP-AEW541, and Cyclopamine, the specific inhibitor of Shh. All rats were divided into five experiment groups by different stimulating additions :(1)Cyclopamine;(2)NVP-AEW541;(3)IGF-1;(4)Cyclopamine+ IGF-1;(5)physiological saline. Unilateral condyle was randomly chosen to make the intra-capsule injection, and then its size was compared to the control condyle. Results: Compared with control condyle, the sizes of the condyle which were local injected with NVP-AEW541, IGF-1, and Cyclopamine+ IGF-1 were significantly smaller (P<0.05). There was no difference on the size of the condyle between cyclopamine and physiological saline stimulation groups (P<0.05). Conclusion: IGF-1 promotes human TMJ cartilage overgrowth in the developing process of condylar hyperplasia. References | Related Articles | Metrics

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Influence of Orthodontic Treatment on Temporomandibular Joint after Surgery of Condylar Hyperplasia LIANG Chang-fu, CHEN Guo-xin, XIAO Xiu-feng, SUN Hui, ZHENG Ya-lei 2018, 34(8): 870-875.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.017 Abstract ( 261 )   PDF (2756KB) ( 364 )   Objective: To evaluate the influence of orthodontic treatment on temporomandibular joint after surgery of condylar hyperplasia (CH) , and to explore the stability of TMJ after surgery. Methords: Twenty patients (8 males and 12 females), aged from 17 to 34 years with an average age of 21.2 years and diagnosed as condylar hyperplasia, were selected after condylectomy high site. Straightwire appliance or invisible appliance was used for the orthodontic treatment. Mini-implants were used to intrude upper posteriors on the affected side. The function of TMJ before surgery, after surgery, and after orthodontic treatment was compared. CBCT, cephalometric film, and Tc99m_MDP SPECT were used to measure the change of joint space specifically. Results: Significant differences were found in TMJ space (including anterior space, posterior space, and superior space) of affected side and normal side after surgery and after orthodontic treatment, whereas no significant difference was found before surgery. Conclusion: Orthodontic treatment with condylectomy high site can improve the facial deformity and malocclusion induced by CH. TMD could also be improved. The condyle will return back to the normal condition in joint fossa after orthodontic treatment and the stability is promising. References | Related Articles | Metrics

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Comparison on Image Segmentation Methods for Patients with Temporomandibular Joint Osteoarthrosis LV Jia-hong, XU Yue, ZHANG Zhi-guang, LIN Han 2018, 34(8): 876-880.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.018 Abstract ( 234 )   PDF (1591KB) ( 454 )   Objective: To compare different algorithms for TMJ CBCT image segmentation and explore an ideal optimization segmentation algorithm. Methods: The CBCT images of 46 TMJ-OA condyles and 46 healthy condyles were included and three-dimensional model was reconstructed. The images of condyles were segmented by the manual segmentation, threshold segmentation, and hybrid algorithm based on borderless active contour model and region growing. The methods were compared concerning time expenditure, adjustability, adaptability of segmentation contours, software interface friendliness score, condylar volume, and surface size. Results: No significant morphological differences were found between manual segmentation and hybrid algorithm segmentation of condyles with TMJ-OA. The volume of condyles with threshold segmentation was significantly smaller than that with the other methods. The value of volume discrepancy was 85.7±296.1mm. The hybrid algorithm segmentation was significantly faster with better usability compared with manual and threshold based segmentation method. Conclusion: The hybrid algorithm segmentation method based on the borderless active contour model and region growing algorithm is a reliable and intelligent approach for condyle contouring in patients with TMJ-OA, which is better than single threshold based segmentation. References | Related Articles | Metrics

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Application of 3D Printing Technique in LeFort I Osteotomy HE Jin-quan, HUANG Luo, OUYANG Ke-xiong, ZHANG Jun-wei, CHEN Lun-qiu, PIAO Zheng-guo 2018, 34(8): 881-884.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.019 Abstract ( 233 )   PDF (1937KB) ( 206 )   Objective: To guide the repositioning of maxilla in Le Fort I osteotomy, and illustrate its feasibility and validity. Methods: Eight patients (4 males and 4 females) with dental maxillofacial deformities were included. The mean age at the time of surgery was 24.6 years (range 18～32 years). Spinal CT scan was used for each patient to create a 3D skull model. The data were imported to Mimics 16.0 to calculate the maxilla and mandible 3D model. The dental cast was scanned with 3shape scanner, which was registered with CT data. The mark plate and position plate were designed with 3-matic software and manufactured via 3D printing technique. All patients were scanned again using spinal CT 7 days postoperatively. The maxilla position of virtual simulation and postoperative actual position were compared with Wilcoxon signed rank test. Results: All patients were operated with the novel method without uncontrolled bleeding, plate break and difficult position. The preliminary results showed that clinically acceptable precision for the position of the maxilla was achieved. All patients were satisfied with the aesthetic results. Conclusions: The preliminary results showed that clinically acceptable precision for the position of the maxilla could be achieved using this 3D printed template. References | Related Articles | Metrics

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Effect of Tooth Abrasion Degree on Accuracy of Cerec Occlusion Contact JIANG Hui, ZENG Li-wei, DENG Lu, JIAO Ji-lan, ZHAN Ai-ping, LI Xiao-xia 2018, 34(8): 885-888.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.020 Abstract ( 225 )   PDF (1338KB) ( 236 )   Objective: To study the effect of different abrasion degree on the accuracy of occlusal contact of optical impression made by CEREC Omnicam chair system. Methods: From December 2016 to June 2017 in patients who visited affiliated Stomatological Hospital of Nanchang University, 84 mandibular first molar teeth were selected as the research object according to the inclusion criteria, including 41 teeth at mild abrasion and 43 teeth at moderate abrasion. CEREC Omnicam chairside system was used to make intraoral optical impression of occlusal contacts. Canon EOS 60D SLR camera was used to record the mouth bite mark image. The overlap rate of the occlusal contact area was calculated and the accuracy of the occlusal contacts of the optical impression was evaluated. Results: The average overlap rates of occlusal contact area in mild abraion group and moderate abraion group were (86.68±1.41) and (87.60±2.06), respectively (P<0.05). Conclusion: The accuracy of occlusal contact of intraoral optical impression of CEREC Omnicam chairside system was high for both mild and moderate wear teeth. Tooth wear has a certain influence on the accuracy of impression. References | Related Articles | Metrics

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Chromatographic Study of Two Nacera Zirconias with Different Transparency ZHOU Yu-fei, LI Qing 2018, 34(8): 889-892.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.021 Abstract ( 221 )   PDF (886KB) ( 251 )   Objective: To study the transparency of two Nacera zirconia systems and their color difference with A2 color of Vita classical shade guide. Methods: The Nacera Pearl and Nacera Shell zirconia blocks were processed by CAD/CAM systems into disc-shaped core porcelain with different thicknesses (0.5mm, 0.8mm, 1.0mm, 1.5mm), then veneered correspondingly with 1.0 mm, 0.7 mm, 0.5 mm, 0.0 mm thick veneer porcelain(Noritake Kizai Co., Nagoya, Japan) of A2 color and glazed. A total of 40 copings of φ10.0 mm, 1.5mm thick zirconia-based ceramic specimens were produced for this study (n=5). PR-655 spectrophotometer was used to measure the color parameters of the specimens against standard black and white plates and 4.0mm thick dentin color resin. Then the relative transparency (TP) and the color difference (ΔE) with A2 color (Vita Lumin Vacuum shade guide) were calculated. Results: TP values of Nacera Shell were significantly smaller than Nacera Pearl. As the core thickness of the Nacera Pearl core increases, ΔE values between specimens and A2 color film became larger, and the color of Nacera Shell changed relatively small. Conclusion: Both systems of Nacera zirconia simulate the A2 color well. However, compared to high transparent zirconia, the color of low transparent zirconia is more stable. References | Related Articles | Metrics

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Effect of Two Kinds of Fiber Post Surface Treatments on Root Fracture Resistance LUO Yi, DAN Hong-ping 2018, 34(8): 893-895.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.022 Abstract ( 199 )   PDF (785KB) ( 176 )   Objective: To analysis different fiber post surface treatments on fracture strength of roots after restoration, and to provide a reference basis for clinical fiber post surface treatment. Methods: Sixty fiber post were randomly divided into three groups: control group, sandblasting group, and hydrogen peroxide acid group. All fiber posts were fixed in the roots in vitro using the same resin and restored with full crown. After treated with the same simulation environment with cold and hot, the flexural crack strength was tested. Results: There was no significant difference on the in vitro teeth length, root length, and neck buccolingual diameter and mesiodistal diameter of three groups, no matter surface treatment method. The most frequent fracture sites after loading was happened at cervical 1/3, which indicated no relationship existed between surface treatment and fracture location and mode. Sandblasting group and hydrogen peroxide treatment group had higher fracture strength than the control group (P<0.05), however, no difference between sandblasting group and hydrogen peroxide group. Conclusion: Sandblasting and hydrogen peroxide treatment can both enhance the fracture strength of fiber post. Surface treatment has no relationship with the fracture mode of fiber post. References | Related Articles | Metrics

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CBCT Analysis of Mesiodistal Angulation of Maxillary Molars for Female Patient with Skeletal Class Ⅱ Malocclusion LI Jun, WANG Zi-yi, ZHANG Xiao-dong 2018, 34(8): 896-901.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.023 Abstract ( 248 )   PDF (1941KB) ( 215 )   Objective: To measures the mesiodistal angulation of maxillary molars of skeletal class II female by CBCT, to provide reference for the clinical treatment. Methods: Thirty patients with skeletal class II malocclusion and 10 cases for normal occlusion were selected. CBCT was taken before treatment and induced into Invivo Dental 5 software. The occlusal plane, frankfort horizontal plane, and the palatal plane were set as the reference plane, the inclinations of the maxillary molars were measured. Individual normal occlusion and skeletal class II malocclusion were examined. One-way ANOVA were used to analyze the differences between high angle group, average angle group, and low angle group of skeletal class II. Pearson correlation analysis was used for different vertical facial types between the measurement items and mandibular plane angle and plane angle. Results: There existed distal inclining trend of the first maxillary molar for the skeletal class II patients. From low-angle group to high-angle group, there existed distally declining trend at the first maxillary molar. When the occlusion plane was for reference, the second maxillary molar has distally inclining trend from high-angle to low-angle. Conclusion: In order to compensate the disharmony between mandible and maxillary, there existed distal trend of maxillary first molar for skeletal class II malocclusion. The first maxillary molar for skeletal class II malocclusion compensated the distal inclination with the increasing of mandible plane angle. However, the distally inclining trend of second molar was not obvious. No matter which kind of skeletal class II vertical facial pattern, the first maxillary molar compensated the inclining movement to maintain the occlusal force to transfer along the long axis of tooth. References | Related Articles | Metrics

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Similarities and Differences of Tooth Movement after Rapid or Slow Maxillary Expansion Observed by CBCT LIU Jun-ling, LI Hong-fa, YAN Hui 2018, 34(8): 902-904.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.024 Abstract ( 229 )   PDF (1300KB) ( 195 )   Objectives: To compare the differences of teeth movement after rapid maxillary expansion or slow maxillary expansion in teenagers. Methods: Forty patients in the growth peak with narrow arch were selected. They were randomly divided into two groups. CBCT imaging technique was used to scan and reconstruct the arch before and after maxillary expansion. The changes of teeth and palate were measured and analyzed statistically. Results: For rapid expansion group, the increase of gap between the crowns was smaller and the increase of gap between the roots was bigger than those of slow expansion group (P<0.05). Conclusion: During maxillary expansion, the teeth have both whole movement and tilt movement. The whole movement in the rapid expansion group was greater than that of the slow expansion group. References | Related Articles | Metrics

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Preparation, Anti-infect Ability in Vitro, and Stability of Multi-layer Sodium Alginate-chitosan Microspheres Loading VEGF and VAN XU Yi-chi, ZHAO Chu-qiao, CHEN Kai, LIU Ding-kun, JIN Ju-lou, SUN Meng-jie, LIU Zhi-hui 2018, 34(8): 905-909.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.025 Abstract ( 240 )   PDF (1691KB) ( 249 )   Objective: To prepare multilayer sodium alginate/chitosan microspheres containing vascular endothelial growth factor (VEGF) and vancomycin (VAN) and discuss their in vitro anti-infective ability and stability. Methods: Multilayer drug-loaded microspheres were prepared by infusion method and layer-by-layer self-assembly technique. The in vitro anti-infective ability of microspheres was tested by paper strip method. The drug loading and encapsulation efficiency of VEGF and VAN in the microspheres were determined by ELISA and UV spectrophotometry. The surface and cross section morphology of microspheres were observed by scanning electron microscope after different temperatures and light treatment of the microspheres. The changes of effective release amount of VEGF and VAN in microspheres after different conditions were determined. Results: The prepared microspheres were spherical in shape. After the microspheres were dissolved, the diameter of the bacteriostatic loop of the solution against Staphylococcus aureus (ATCC25923) was (12.61±1.01)mm. After treatment under different conditions, the microspheres diameter was 900-1100μm, the surface was complete. There was a little fold, and the cross-section was dense network structure. The drug loading of VEGF and VAN in the microspheres were 6.63 × 10-5% and 1.39%, respectively, and the encapsulation efficiencies were 72.1% and 3.37%, respectively. Under different conditions, the effective release amount of VEGF and VAN in the microspheres decreased. Conclusion: An uniform particle size was prepared, which had certain inhibitory effect on Staphylococcus aureus and required low temperature (-80℃) dark storage. References | Related Articles | Metrics

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Proliferation and Differentiation of Osteoclast-like Cells on Calcium Phosphate/Zn/Sr Coatings LONG Tian, CHENG Zhi-gang 2018, 34(8): 910-912.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.026 Abstract ( 281 )   PDF (817KB) ( 198 )   Objective: To verify the hypothesis that the incorporation of strontium (Sr) or zinc (Zn) into electrodeposited calcium phosphate coatings (ECP) does not influence the proliferative ability and differentiation potential of osteoclasts. Methods: Titanium alloy plates electrolytically coated with calcium phosphates with or without Sr or Zn were incubated with osteoclast-like RAW264.7 cells for eight days. The proliferation index within 6 days and the differentiation after 8 days were analyzed. Results: Although presenting different cell attachment pattern, the osteoclast-like cells demonstrated similar differentiation potential. Coatings with Zn presented statistical lower cell proliferative ability. Conclusion: Electrodeposited calcium phosphate coatings with Zn enhanced the attachment of osteoclasts. The incorporation of Sr and Zn to the electrodeposited calcium phosphate coatings does not influence the proliferation and differentiation of osteoclast-like cells References | Related Articles | Metrics

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Fabrication and Characterization of Fibrous Barrier Mat of Poly(L-lactide-co-caprolactone)/silk Fibroin Loaded with PTH-Fc ZHU Yi-dan, HE Miao-miao, LIU Jia-tao, LIU Yan-yun, LIU Yu-hui, XU Ning, TANG Yi-yue, YU Zhan-hai 2018, 34(8): 913-918.  DOI: 10.13701/j.cnki.kqyxyj.2018.08.027 Abstract ( 196 )   PDF (3702KB) ( 271 )   Objective: To fabricate fibrous barrier mat of poly(L-lactide-co-caprolactone)/silk fibroin loaded with PTH-Fc via electrospinning technique, and to study its biocompatibility, biodegradability, mechanical strength, and ability to regulate appropriate cellular activities. Methods: Electrospun fibrous poly(L-lactide-co-caprolactone)/silk fibroin loaded with PTH-Fc (PLCL/SF/PTH-Fc) or without (PLCL/SF) were prepared and compared. Apparent morphology before and after degradation were observed by scanning electron microscope (SEM). Tensile property was tested by custom mechanical testing device. The biocompatibility of PLCL/SF/PTH-Fc was evaluated by MTT and the cell adhesion assay. The osteogenic potential of the cells cultured with PLCL/SF/PTH-Fc was investigated by alizarin red stain. Results: The nanofibers of PLCL/SF/PTH-FC were uniform and smooth. The breaking strengths of PLCL/SF/PTH-Fc and PLCL/SF were (5.56±0.18) MPa and (5.42±0.03) MPa, respectively (P>0.05). PLCL/SF/PTH-Fc mats could degrade quickly, promote the cell proliferation, and induce the cell differentiation. Conclution: Electrospun fibrous PLCL/SF/PTH-Fc has good mechanical property and biodegradability. It can promote cell proliferation and cell differentiation. References | Related Articles | Metrics