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Table of Content
01 October 2018, Volume 36 Issue 5
  • Oral health management for children
    Jing Zou
    West China Journal of Stomatology. 2018, 36(5):  465-468.  doi:10.7518/hxkq.2018.05.001
    Abstract ( 2615 )   HTML ( 252 )   PDF(pc) (1697KB) ( 1601 )   Save
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    Pediatric dentistry should focus not only on the treatment of various oral diseases during the entire growth and development of children but also on the early prevention, diagnosis, and intervention of various oral diseases in this process. Early identification and removal of risk factors or early intervention for common oral diseases is necessary to the implemen-tation of oral health management for pregnant women, infants, preschool and school-age children, and adolescents with diffe-rent general and oral physiological characteristics and common oral diseases. The treatment enables the growth and develop-ment of the teeth, as well as occlusion and facials along the normal trajectory, ultimately achieving the functional perfection and aesthetic coordination of the cranio-maxillary and occlusion.

    Current situation and strategy on perforation repair
    Shihai Yin
    West China Journal of Stomatology. 2018, 36(5):  469-474.  doi:10.7518/hxkq.2018.05.002
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    Perforations are common complications of root canal therapy. In clinic, perforations that were improperly and untimely repaired can seriously affect the prognosis of teeth after root canal treatment. At present, the status of perforation repair in our country is worrisome. This paper focused on the progress of perforation repair in the country by discussing the current situation of repair methods and materials. This review aims to improve knowledge and aid clinical doctors in the sophistication of perforation repair in order to improve the retention rate of root-canal-treated teeth.

    Expression of triggering receptors expressed by myeloid cells-1 in macrophages stimulated by Porphyromonas gingivalis-lipopolysaccharide
    Yun Yang,Shanshan Chen,Chunmei Xu,Yafei Wu,Lei Zhao
    West China Journal of Stomatology. 2018, 36(5):  475-481.  doi:10.7518/hxkq.2018.05.003
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    Objective Soluble triggering receptors ex-pressed by myeloid cells-1 (sTREM-1) and inflammatory cytokine tumor necrosis factor-α (TNF-α) in macrophage cells were stimulated by Porphyromonas gingivalis-lipopolysac-charide (Pg-LPS) to investigate the expression of triggering receptors expressed by myeloid cells-1 (TREM-1) and further explore the correlation between TREM-1 and the pathogenesis of periodontitis. Methods THP-1 cells (a human monocytic cell line derived from an acute monocytic leukemia patient) were induced to differentiate THP-1 macrophages by phorbol-12-myristate-13-acetate and were injected with 0 (blank control), 0.5, or 1.0 μg·mL -1 Pg-LPS. The THP-1 cells were then grouped in accordance with incubation time, and each group was incubated for 4, 6, 12, or 24 h. The expression of the TREM-1 mRNA in macrophages was detected by real-time quantitative polymerase chain reaction, while the expression of TREM-1 protein was detected by Western blot; the site where TREM-1 protein expression was observed in macrophages was detected by immunofluorescence staining, and the expression of soluble sTREM-1 and TNF-α in cell culture medium was detected by enzyme-linked immunosorbent assay. Results Compared with the blank control group, the expression of TREM-1 mRNA, TREM-1 protein, and sTREM-1 in Pg-LPS-stimulated macrophages was significantly upregulated (P<0.05). The expression of TREM-1 mRNA, TREM-1 protein, and sTREM-1 in the supernatant of cell culture was higher in the 1.0 μg·mL -1 Pg-LPS group than in the 0.5 μg·mL -1 group; this expression was statistically significant since the 6, 4, and 4 h time point (P<0.05). Cell immunofluorescence staining showed that TREM-1 protein was positive when the THP-1 macrophages was stimulated by Pg-LPS (1.0 μg·mL -1) for 24 h, and the staining sites of TREM-1 were mainly located in the cell membrane of the macro-phages (P<0.05). The expression level of TNF-α increased in groups stimulated by Pg-LPS, and the expression level of TNF-α was significantly higher in 1.0 μg·mL -1 Pg-LPS stimulated groups than in 0.5 μg·mL -1 Pg-LPS-stimulated groups since the 6 h time point (P<0.05). The expressions of TREM-1 mRNA, TREM-1 protein, and sTREM-1 in 0.5 μg·mL -1 Pg-LPS-stimulated macrophages were positively correlated with one another (r=1, P<0.05), but no statistically significant correlation was found in the expression of TNF-α. The positive correlation between sTREM-1 and TNF-α expressions was detected when macrophages were stimulated by 1.0 μg·mL -1 Pg-LPS (r=1,P<0.05). Conclusion The expression of TREM-1 mRNA, TREM-1 protein, and sTREM-1 in the culture supernatant in Pg-LPS-stimulated macrophages was significantly upregulated on the basis of the concentration of Pg-LPS; moreover, their upregulation was positively correlated with one another. The expression of TNF-α in the supernatant of cell culture was also upregulated and was positively correlated with the expression of sTREM-1 at the group of high Pg-LPS concentration (1.0 μg·mL -1). Results reveal that TREM-1, which has been realized as a proinflammatory receptor protein, can promote the development of periodontitis by regulating the expression of TNF-α in macrophages.

    Effects of bond strength evaluation on different durations of adult permanent teeth and youth permanent teeth by using universal adhesives to dentin
    Yuan Sun,He Liu,Zhihui Sun
    West China Journal of Stomatology. 2018, 36(5):  482-487.  doi:10.7518/hxkq.2018.05.004
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    Objective To compare the dentin bonding strength evaluation between adult permanent teeth and youth per-manent teeth after treatment for different durations by universal adhesives. Methods Ten adult permanent teeth and ten youth permanent teeth were selected for this study. The occlusal enamel layer was removed, and each tooth was cut into three pieces along the long axis. In total, 30 pieces of adult and youth teeth were prepared. The adult and youth teeth pieces were randomly divided into three groups and treated by universal adhesives for 10, 20, and 30 s. In this study, Scotchbond Universal (SBU) was selected as the universal adhesive. Slabs were treated by dual-cure resin cements. The specimens were tested by micro-shear strength test through a universal testing machine. Fracture modes were observed by a stereomicroscope. Other adult teeth and youth teeth were selected, two for each type, and treated and grouped in the same manner. Fluorescein (0.1% Rhodamine B) was dissolved in SBU adhesive, and the specimens were treated by the adhesives for 10, 20, and 30 s. Micromorphology of the resin protrusions on the adhesive surface was observed by laser confocal microscopy (CLSM). Results For the adult teeth, the highest micro-shear bonding strength was observed in the 20 and 30 s groups, and the values were higher than that of the 10 s group (P<0.05). For the youth teeth, the highest micro-shear bonding strength was observed in the 10 and 20 s groups, and the values were higher than that of the 30 s group (P<0.05). The micro-shear bonding strength in the 10 s youth teeth group was higher than that of the 10 s adult teeth (P<0.05) and was same as the adult teeth treated for 20 s (recommendation time of material instructions) (P>0.05). The main break patterns in different groups comprised adhesive failure fractures and several mixed failure fractures. No resin fracture mode was observed. CLSM revealed very few short resin protrusions in 10 s adult teeth group, whereas the number and length of resin protrusions significantly increased in the 20 s adult teeth group. The resin protrusions of the 30 s group were shorter than those of the 20 s adult teeth group. In different durations, the bonding interface in different youth teeth groups presented the same trend of change as the adult teeth. However, the number and length of resin protrusions in the 10 s group of youth teeth were all higher than those of the 10 s adult teeth group. Conclusion In clinical practice, the bonding agent treatment duration shall be shortened appropriately for youth permanent teeth, and that for adult permanent teeth shall not be shortened to less than 20 s. On the whole, the bond strength of youth permanent teeth can achieve no significant difference with the adult permanent teeth.

    Comparison of stripping of steep sheep maxillary sinus mucosal with new-type memory elastic silk sleeve stripper and umbrella stripper
    Changjian Li,Yuan Lü,Yanfeng Li,Jiadong Fan,Le Liu,Yue Zhang
    West China Journal of Stomatology. 2018, 36(5):  488-492.  doi:10.7518/hxkq.2018.05.005
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    Objective This work aims to investigate the effect of stripping of steep sheep maxillary sinus by using 0.012 or 0.014 model new-type memory elastic silk sleeve stripper and umbrella stripper. Methods Goats with sinus floor gradients of 60° to 90° were selected by computed tomography of sheep head. A total of 72 animal models were established and rando-mized into three groups (n=24): group A (0.012 model), B (0.014 model) and C (umbrella stripper). Alveolar and maxillary sinus mucosa were stripped after crowning, and stripping length was measured when the stripping limit was reached or mucosal perforation occurred. Results The average stripping length of mucosa in group A was 11.3 mm±4.6 mm, and three cases experienced perforation of sinus floor mucosa. The average stripping length of mucosa in group B was 17.5 mm±5.0 mm, and one case experienced perforation of sinus floor mucosa. The average stripping length of mucosa in group C was 4.2 mm±1.3 mm, and four cases experienced perforation of sinus floor mucosa. The difference among the three groups was statistically significant (P<0.01) according to variance analysis. Moreover, the comparison between any two means was also statistically significant according to Dunnett’s T3 test (P<0.05). Conclusion The new-type memory elastic silk sleeve stripper effectively stripped steep maxillary sinus mucosa. The 0.014 model exhibited superior peeling effect and was relatively safe.

    Three-year retrospective clinical evaluation of pulp-less molars with defects of varying degree repaired by cast ceramic onlays of three marginal types
    Weilin Qiang,Yuxuan Li,Gang Liu,Lihong Zhang,Jingyang Zhang,Wenjin Cao
    West China Journal of Stomatology. 2018, 36(5):  493-497.  doi:10.7518/hxkq.2018.05.006
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    Objective This study aimed to evaluate the clinical effect of pulp-less molars with defects of different degrees repaired by cast ceramic onlays of three marginal types. Methods A total of 165 endodontically treated molars of 105 patients were included in this study and were divided into three kinds of defect (mild, moderate, severe) according to the number of remaining axial walls. Each defect was divided into three groups according to the shape of edge to edge, bevel edge, and con-cave shoulder. After tooth preparation, the casting of ceramic onlays was performed. Treatment follow-up was done for the evaluation of the success and survival rates of three groups under the same defect. Results The average follow-up was 925.44 days. Under the mild defect, the success and survival rates of the edge to edge onlays were respectively 100% and 100%; bevel edge onlays, 100% and 100%; and concave shoulder onlays, 94.4% and 100%. Under the moderate defect, the success and survival rates of the edge to edge onlays were respectively 96.0% and 100%; bevel edge onlays, 80.0% and 93.3%; and concave shoulder onlays, 95.2% and 95.2%. Under the severe defect, the success and survival rates of the edge to edge onlays were respectively 95.2% and 100%; bevel edge onlays, 73.7% and 89.5%; and concave shoulder onlays, 73.3% and 80.0%. Under different defects, the success or survival rates of the three kinds of onlays had no significant difference (P>0.05). Conclusion The edge to edge type is the most preferable way of onlay tooth preparation and can achieve good clinical results in the mild, middle, and severe tooth defection with root canal treatment.

    Radiological characteristics of the cyst-like lesion of condyle in temporomandibular joint by cone beam computed tomography
    Shu Li,Jie Lei,Kaiyuan Fu
    West China Journal of Stomatology. 2018, 36(5):  498-502.  doi:10.7518/hxkq.2018.05.007
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    Objective To analyze the radiological characteristics and classifications of the cyst-like lesion of condyle in temporomandibular joint (TMJ) by cone beam computed tomography (CBCT). Methods The study was conducted retros-pectively on TMJ images from 194 patients who underwent CBCT examinations. Location, size, amount, surrounding bone trabecula, cortical bone white line of cyst-like lesion, and the overall condition of the condylar bone were evaluated. According to the overall condition of the condylar bone, the cyst-like lesion of condyle were divided into typesⅠand Ⅱ. The location, size, amount, surrounding bone trabecula, and cortical bone white line of the two types of cyst-like lesions were compared. Results In 198 condylars of 194 patients, cyst-like lesions were detected in the left side of 94 patients, in the right of 96 patients, and in both sides of 4 patients. The size of lesions ranged from 1.2 mm to 13.5 mm, with an average size of (3.4±1.5) mm. Half of the cyst-like lesions were located underneath the anterior lateral cortical bony layer (99 condylars, 50.0%). Most cyst-like lesions were solitary (149 condylars, 75.3%), while 62.6% (124 condylars) were surrounded by continuous bony white lines. Bone sclerosis could be observed in 160 condylars (80.8%). A total of 132 condyles (66.7%) were accompanied by changes in late-stage osteoarthrosis, while the others were only accompanied by early-stage osteoarthrosis (10 osteoarthrosis, 5.1%) or showed no evidence of osteoarthrosis (56 osteoarthrosis, 28.3%). Statistical difference were observed in the location, amount, and surrounding bone trabecula of the two types of cyst-like lesions. TypeⅠcyst-like lesions had more frequent and bone sclerosis than type Ⅱ, whereas type Ⅱ cyst-like lesions occurred more on condylar internal or condyle neck than typeⅠ. Conclusion The pathogenesis and mechanism of the two types of cyst-like lesions may be different from each other.

    Associations among PRDM16 polymorphisms, environmental exposure factors during mother’s pregnancy, and non-syndromic cleft lip with or without cleft palate
    Bin Yin,Bing Shi,Zhonglin Jia
    West China Journal of Stomatology. 2018, 36(5):  503-507.  doi:10.7518/hxkq.2018.05.008
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    Objective We aimed to study the association between rs7525173, rs2236518, rs2493264 single nucleotide poly-morphism (SNP) in the PRDM16 gene, smoking, alcohol exposures, and nonsyndromic cleft lip with or without cleft palate (NSCL/P). Methods A total of 157 case-parent trios were selected, and SNPs were genotyped by using ligase detection reaction (LDR) and direct sequencing methods. Transmission disequilibrium test (TDT) and linkage disequilibrium (LD) tests were con-ducted to analyze the data. A total of 1 710 patients with orofacial clefts and 956 healthy newborns were enrolled in the epide-miological survey. The smoking and drinking exposures of parents during early pregnancy were analyzed. Results The C allele at rs2236518 was over-transmitted for NSCPO (P<0.05). Statistical differences were observed among three factors, namely, maternal smoking, maternal passive smoking, and maternal drinking (P<0.05). Conclusion The rs2236518 at PRDM16 gene, maternal smoking, maternal passive smoking, and maternal drinking were closely related to the occurrence of NSCL/P.

    Saliva of periodontitis patients promotes macrophage differentiation and activation
    Xiaoying Li,Qian Li,Bomiao Cui,Liwei Wang,Yaping Fan,Jiao Chen,Yun Feng,Ping Zhang
    West China Journal of Stomatology. 2018, 36(5):  508-513.  doi:10.7518/hxkq.2018.05.009
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    Objective The aim of this study was to investigate the effect of saliva of patients with chronic periodontitis (CPD) on the differentiation, activation, and secretion of osteoclast-maturing mediators of macrophages. Methods A total of 40 saliva samples were collected from healthy donors (n=20) and severe periodontitis patients (n=20). Peripheral blood mono-nuclear cells (PBMCs) and THP-1 monocyte line cells were challenged with 15% saliva for 5 days. The phenotype, surface marker, and phagocytosis of macrophages were analyzed by flow cytometry and microscopy. Osteoclast-maturing mediators were assayed by using enzyme-linked immunosorbent assay (ELISA) kits. Results When PBMCs were treated with CPD saliva for 5 days, 61.25%±11.33% of cells were transformed into large granular cells; 86.78%±13.69% of large granular cells were identified as CD14 ++CD16 +macrophages. When THP-1 cells were treated with CPD saliva, most cells attached to thebottom of cell culture plates, thereby exhibiting macrophage morphology and releasing additional osteoclast-maturing mediators. Furthermore, the phagocytosis of THP-1 cells considerably increased in the presence of CPD saliva (66.35%±9.67%) compared with medium control (33.33%±7.52%), or healthy saliva (40.71%±3.52%).Conclusion Saliva from patients with CPD can induce macrophage differentiation, activate phagocytose microorganisms, and secrete osteoclast-maturing mediators.

    Impacts of periodontitis on visceral organ weight and weight percentage in obese mice
    Ting Yu,Li Zhao,Jincai Zhang,Dongying Xuan
    West China Journal of Stomatology. 2018, 36(5):  514-520.  doi:10.7518/hxkq.2018.05.010
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    Objective This study aimed to explore the impacts of periodontitis on the visceral weight and weight percen-tage of obese animal models. Methods A total of 64 C57BL/6J mice were divided into the following diet groups: high-fat diet (HFD) group (n=36), which was fed with high-fat diet to induce obesity, and low-fat diet (LFD) group (n=28), which was fed with low-fat diet as the control. After 16 weeks on diet, each diet group was divided into periodontitis (P) and control (C) groups. The P groups were induced for periodontitis by ligation with Porphyromonas gingivalis-adhered silk for 5 or 10 days, and the C groups were sham-ligated as the control. Visceral organs were resected and weighed. The organ weight percentage was calculated. Results Compared with the LFD group, the HFD group significantly upregulated the weight and weight percentage of visceral adipose tissue and spleen (P<0.05), upregulated the weight of liver and kidney (P<0.05), and down-regulated the weight percentage of liver and kidney (P<0.01). In the HFD group, the weight and weight percentage of spleen were downregulated in the P group (P<0.05), but were up-regulated in the 10-day group compared with the 5-day group (P<0.05). Conclusion Periodontitis can affect the general morphology of the viscera (especially spleen) in obese animal models. Pathological indications in terms of immunometabo-lism might be present in the correlation between obesity and periodontitis.

    Effect of water immersion on a dental self-healing and antibacterial resin composite
    Junling Wu,Tong Li,Xu Gao,Qiang Zhang,Di Liu,Jianhua Ge,Chuanjian Zhou
    West China Journal of Stomatology. 2018, 36(5):  521-527.  doi:10.7518/hxkq.2018.05.011
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    Objective This investigation aimed to develop a novel self-healing and antibacterial dental resin composite. The effects of water immersion on its properties were also evaluated. Methods Microcapsules filled with healing agent of triethylene glycol dimethacrylate were synthesized on the basis of previous studies. Antibacterial resin composite contained nano-antibacterial inorganic fillers that were modified by quaternary ammonium salt with long-chain alkyl. Microcapsules were incorporated into antibacterial resin composite at mass fraction of 7.5%. A commercial resin composite named Tetric N-Ceram was used as control. The resin samples were immersed in 37 °C distilled water for different periods. A flexural test was used to measure the mechanical properties of the novel resin composite. A single-edge V-notched beam method was used to measure fracture toughness and self-healing efficiency. A dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony-forming units (CFU) and lactic acid production of biofilm on the novel resin composite were calculated to test the antibacterial property. Results Mechanical properties and fracture toughness decreased significantly after the composite was immersed in water for 30 days (P<0.05), and no significant reduction was found from then on (P>0.05). Water immersion did not weaken the self-healing capability of the composite (P>0.05), and self-healing efficiency of 64% could still be obtained even after 270 days. The antibacterial resin composite showed a strong inhibition effect on the biofilm metabolic activity versus water immersion time from 1 day to 270 days. Therefore, the com-posite could still have a promising antibacterial property even after being immersed in water (P<0.05). Conclusion Water immersion could weaken the mechanical properties of the novel self-healing and antibacterial resin composite, but it insig-nificantly affected the self-healing and antibacterial properties of the composite.

    Effects of body-shade resin layer thickness on the color of polyetheretherketone-Crea.lign restorations
    Jingting Zhang,Jun Su,Yanbo Yuan,Lijia He,Wenyun Zhang
    West China Journal of Stomatology. 2018, 36(5):  528-531.  doi:10.7518/hxkq.2018.05.012
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    Objective This study aims to assess the effects of the different thicknesses of body-shade resin layers on the color of polyetheretherketone (PEEK)-Crea.lign restorations. Methods Five PEEK specimens with the thickness of 0.6 mm were prepared. The color values of PEEK specimens were measured. Afterward, opaque-shade resin layers (0.1 mm) and body-shade resin layers (1.5 mm) were stacked with mold. The five specimens were evenly ground to a thickness of 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.2, and 0.0 mm in sequence. After grinding and ultrasonic cleaning, the color value was measured. Results With the constant thickness of PEEK and 0.1 mm thickness of opaque-shade resin layer, the L*, a*, and b* values all showed downward trend with the increased thickness of the body-shade resin layer (1.0-1.4 mm). With the constant thickness of PEEK and 0.1 mm thickness of opaque-shade resin layer, the color difference between the adjacent groups was less than 1.5 NBS. This difference between nonadjacent groups was more than 1.5 NBS when the thickness of the body-shade resin layer reached 0.6 mm. Color difference between PEEK-Crea.lign restoration and PEEK was more than 1.5 NBS. Conclusion The thick-ness change in the body-shade resin layers influence the color of the PEEK-Crea.lign restorations. Using A2 shade Crea.lign, opaque-shade resin layer thickness is 0.1 and 0.6 mm thickness of body-shade resin layer can produce color which clinically acceptable.

    Selective laser sintering and performances of porous titanium implants
    Ting Wei,Xinwei Zhang,Huiqiang Sun,Mengyun Mao
    West China Journal of Stomatology. 2018, 36(5):  532-538.  doi:10.7518/hxkq.2018.05.013
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    Objective This work aims to analyze the mechanical properties and biocompatibility of porous titanium (Ti) implants fabricated by selective laser sintering (SLS) and investigate the promotion of osseointegration by porous titanium implant combined with chitosan (CS)/hydroxyapatite(HA) composite coating. Methods Ti6Al4V specimens were prepared, and CS/HA composite coating was fabricated on the surface of a portion of the specimens. The mechanical properties of the samples were observed by scanning electron microscope. MC3T3-E1 cells were cultured in vitro, and their biological properties in vitro were analyzed using live and dead viability cell staining method, methyl thiazolyl tetrazolium (MTT) staining, and alkaline phosphatase (ALP) level detection. The thread implant specimens were implanted in the femoral condyle of rabbits, and biological performance was evaluated in vivo. Results Quasi-elastic gradient of porous specimens decreased with in-creasing porosity, and the quasi-elastic gradient were close to cortical and cancellous bone when the porosities were 30% and 70%. The specimens showed good biocompatibility. Combined with CS/HA coating, the implants promoted the proliferation and differentiation of MC3T3-E1 cells and facilitated the entry of bone tissue into pores and good osteogenesis. Conclusion The porous titanium implant exhibited favorable mechanical properties and biocompatibility. Combined with CS/HA coating, the implant exhibited bone inducibility, which leads to stable osteogenesis.

    Effect of different sandblasting conditions on the metal-ceramic bonding strength of Co-Cr alloy fabricated by selec-tive laser melting technology
    Qianqian Yu,Jing Guo,Hongshui Zhu
    West China Journal of Stomatology. 2018, 36(5):  539-543.  doi:10.7518/hxkq.2018.05.014
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    Objective To investigate the effect of different sandblasting conditions on the metal-ceramic bonding strength of Co-Cr alloy fabricated by selective laser melting (SLM) technology. Methods A total of 63 specimens of Co-Cr alloy fabricated by SLM were prepared and randomly divided into nine groups (n=7). Each group was treated with different powder particles (A1=50 μm, A2=100 μm, and A3=150 μm) and pressures (B1=0.2 MPa, B2=0.4 MPa, and B3=0.6 MPa) in sand-blasting. One sample was randomly selected from each group for microstructure observation by scanning electron microscope (SEM). Ceramic was fired at the center of the specimens. Metal-ceramic bonding strength was measured with universal testing machine. Results were statistically analyzed with SPSS 17.0 software. Results The mean bond strengths were as follows: Group A1B1: 27.22 MPa±0.95 MPa, Group A1B2: 27.58 MPa±0.47 MPa, Group A1B3: 26.80 MPa±0.71 MPa, Group A2B1:27.54 MPa±0.78 MPa, Group A2B2: 30.75 MPa±0.43 MPa, Group A2B3: 26.93 MPa±0.88 MPa, Group A3B1: 28.18 MPa±0.93 MPa, Group A3B2: 29.55 MPa±0.57 MPa, and Group A3B3: 28.11 MPa±0.91 MPa. The particle factor of Al2O3 and the pressure factor of blasting showed statistical significance (P<0.05). An interaction was observed between the factors of particle and pressure (P<0.05). Mixed fracture mode of all specimens was observed after the shear strength test. Conclusion In conclusion, metal-ceramic bonding strength reaches the maximum when specimens are sandblasted with 100 μm alumina oxide at 0.4 MPa pressure.

    Invasion and metastasis mechanism of human papillomavirus in head and neck squamous cell carcinomas
    Guang-xue Cui,Xiaolei Gao,Xinhua Liang
    West China Journal of Stomatology. 2018, 36(5):  544-551.  doi:10.7518/hxkq.2018.05.015
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    Human papillomavirus (HPV) is a major causative agent of head and neck squamous cell carcinomas (HNSCC). Over the past several decades, an increasing number of studies established the strong association of HPV with the invasion and metastasis of HNSCC. In the present study, we reviewed the gene mutations in HPV-associated HNSCC and the unique mechanism of E6- and E7-mediated carcinogenesis via interactions with an array of cellular elements. We further discussed the progress in the mechanisms of invasion and metastasis; these mechanisms include non-coding RNAs, deregulating cellular energetics, tumor microenvironment, cancer stem cells, angiogenesis, and lymphangiogenesis.

    Development and homeostasis of taste buds in mammals
    Xin Zheng,Xin Xu,Jinzhi He,Ping Zhang,Jiao Chen,Xue-dong Zhou
    West China Journal of Stomatology. 2018, 36(5):  552-558.  doi:10.7518/hxkq.2018.05.016
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    Taste is mediated by multicellular taste buds distributed throughout the oral and pharyngeal cavities. The taste buds can detect five basic tastes: sour, sweet, bitter, salty and umami, allowing mammals to select nutritious foods and avoid the ingestion of toxic and rotten foods. Once developed, the taste buds undergo continuous renewal throughout the adult life. In the past decade, significant progress has been achived in delineating the cellular and molecular mechanisms governing taste buds development and homeostasis. With this knowledges and in-depth investigations in the future, we can achieve the precise management of taste dysfunctions such as dysgeusia and ageusia.

    The role of bone morphogenetic protein signaling pathway in tooth root development
    Cangwei Liu,Yijun Zhou,Guangxing Yan,Ce Shi,Xue Zhang,Yue Hu,Xinqing Hao,Huan Zhao,Hongchen Sun
    West China Journal of Stomatology. 2018, 36(5):  559-563.  doi:10.7518/hxkq.2018.05.017
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    The bone morphogenetic protein (BMP) family is an important factor in the regulation of cell ular life activities and in the development of almost all tissues. BMP-mediated signaling plays an important role in tooth root development, which is a part of tooth development. Epithelial and mesenchymal interactions are involved in tooth root development, but the BMP signaling pathway has a different effect on tooth root development in epithelial and mesenchymal. This review summarizes the advances of BMP signaling in tooth root development.

    Prevention of infectious diseases through microecology modulation techniques
    Hui Wang,Di Kang,Xuedong Zhou,Yuqing Li
    West China Journal of Stomatology. 2018, 36(5):  564-567.  doi:10.7518/hxkq.2018.05.018
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    The microbe is small in volume, but large in quantity and species. The symbiotic microbe, which is far more than human cells, code millions times of genes than human being. Somatic cells and these symbiotic microbe distributing in human body skin, respiratory tract, oral cavity and gastrointestinal tract, urinary tract and other parts form a complex ecosystem whose dynamic balance is highly related to body health. With the successful implementation of Human Microbiome Project, more attentions have been paid to the next generation microbiome technologies. New tools and methods for ecological regulation of human microbiome are emerging. The way we improve the world of human microbiology will be more convenient. This paper will make a review on the modulation techniques of human microbiome.

    Progress on medication-related osteonecrosis of the jaw
    Qizhang Wang,Jiyuan Liu,Jian Pan
    West China Journal of Stomatology. 2018, 36(5):  568-572.  doi:10.7518/hxkq.2018.05.019
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    Medication-related osteonecrosis of the jaw (MRONJ) is a severe complication of bisphosphonates (BPs) or other targeted agent therapies. MRONJ appears as exposed bone, pus, and swelling in the oral and maxillofacial regions. However, neither surgery nor conservative therapy can eliminate symptoms thoroughly. In addition to BPs, several antire-sorptive and antiangiogenic agents, such as denosumab and bevacizumab, as well as targeted agents, such as sunitinib and temsirolimus, can cause osteonecrosis of the jaw according to the literature. This review aims to summarize the research progress on these new drugs.

    Primary acinic cell carcinoma in mandible: a case report
    Kyojin Kim,Qiaoshi Xu,Chong Wang,Bo Li,Zhengxue Han,Zhien Feng
    West China Journal of Stomatology. 2018, 36(5):  573-575.  doi:10.7518/hxkq.2018.05.020
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    Acinic cell carcinoma is a relatively rare salivary gland tumor predominantly occurring in the major glands. Therefore, acinic cell carcinoma rarely occurs in the mandible. In this study, a case of primary acinic cell carcinoma of the mandible was reported, and relevant literature was reviewed. The etiology, clinical symptom, image and histological features, diagnosis, treatment, and prognosis of acinic cell carcinoma in the mandible were discussed.

    Mandibular first molar with C-shaped root canal system: a two-case report
    Di Wu,Jin Zhang,Wei Wang,Bing-chang Xin
    West China Journal of Stomatology. 2018, 36(5):  576-579.  doi:10.7518/hxkq.2018.05.021
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    The root and canal anatomy of the mandibular first molar is highly complicated. A mandibular first molar with a C-shaped root canal system is rare. This article describes two different cases of this system. Case 1 has a complete C-shaped fused root. The root canal is characterized by a mesial lingual root canal and a C-shaped fused root canal. Case 2 has a C-shaped fused root in the buccal region and a distal lingual root. The root canal is characterized by a type Ⅱ-Ⅰroot canal in the buccal region and a distal lingual root canal.