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Table of Content
01 December 2013, Volume 31 Issue 6
  • Adult orthodontic technique: development and challenge
    Li Song, Zhou Jiemin, Ren Chaochao
    West China Journal of Stomatology. 2013, 31(6):  549-551.  doi:10.7518/hxkq.2013.06.001
    Abstract ( 1827 )   HTML ( 30 )   PDF(pc) (968KB) ( 1745 )   Save
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    Orthodontic treatments have increasingly become accepted by adults. However, the treatment therapies and philosophies for adults and adolescents have numerous differences. Orthodontic treatment for adults requires more careful planning, flexible management, interdisciplinary cooperation, and rational expectations. New techniques, such as mini-screw implants, invisalign, and self-ligating brackets, have recently been used to update treatments and widen the application of adult orthodontics by improving the treatment results. However, orthodontists still face a number of risks and challenges.

    Three-dimensional finite element analysis of the effect of the location and diameter of implants on the stress distribu-tion in three-unit implant-supported posterior cantilever fixed partial dentures under dynamic loads
    Lü Jia, Liu Cuiling3, Lan Jing, Gao Xu
    West China Journal of Stomatology. 2013, 31(6):  552-556.  doi:10.7518/hxkq.2013.06.002
    Abstract ( 1204 )   HTML ( 12 )   PDF(pc) (1058KB) ( 873 )   Save
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    Objective To examine the effect of the location and diameter of implants on stress distribution in three-unit implant-supported posterior cantilever fixed partial dentures (FPD) in the mandible. Methods A three-dimensional finite element model was developed to represent a rigid implant-supported posterior FPD that restores the second left premolar, first molar, and second molar. The location of the distal implant with a diameter of 4.8 mm remained the same, whereas the mesial implants with diameters of 4.1 and 4.8 mm were successively moved toward the posterior area with distances of 5.5, 8.0, 10.5, and 13.0 mm from the long axis of the mesial implants to the first premolar to form the cantilever FPD. Dynamic loads of 250 N were applied from different directions on the buccal and lingual cusps of the FPD to simulate the masticatory cycle for 0.875 s. The maximum Von Mises stresses were calculated using the finite element analysis software MSC. Marc and Partran. Results The maximum Von Mises stresses of the mesial and distal implants increased to some extent as the me-sial implants moved toward the posterior area. Significant increases in the maximum Von Mises stresses were obtained when the mesial implants were located more than 8.0 mm posterior to the first premolar, and moderate increases in the stresses were observed when the mesial implants were located less than 8.0 mm posterior to the first premolar. The use of a broader implant reduced the stress on the interface between the bone and the implants. The maximum Von Mises stresses were found in the cervical region of the cortical bone adjacent to the mesial or the distal implants during stages Ⅱ to Ⅳ of the masticatory cycle. Off-axial loading induced more stresses compared with vertical loading. Conclusion The location of implants in three-unit implant-supported posterior cantilever FPD is a significant factor that influences the stress generated in the interface between the bone and the implants. An implant-supported cantilever FPD is a feasible option for restoring missing teeth when the length of the cantilever is not greater than the width of a premolar. Two important factors should be considered before choosing the implant diameter, namely, bone volume and cantilever length.

    Mini-implant stability analysis at different healing times before loading
    Shan Lihua, Zhou Guanjun, Li Xingchao, Qie Hui, Dong Fusheng
    West China Journal of Stomatology. 2013, 31(6):  557-560.  doi:10.7518/hxkq.2013.06.003
    Abstract ( 1099 )   HTML ( 6 )   PDF(pc) (5180KB) ( 1058 )   Save
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    Objective  This study aims to biomechanically analyze a mini-implant at different healing times before loading. Methods  Sixty-four mini-implants with (12±1) N·cm insertion torque were placed in the low jaw of eight beagle dogs. The test mini-implants remained in the low jaw for 0, 1, 3, and 8 weeks of bone healing and for an additional 10 weeks under a force of 0.98 N. The unloaded control implants were further divided into four groups (1, 3, 8, and 10 weeks). Maximum removal torque (MRT) testing was performed to evaluate the interfacial share strength of each group. Surface analysis of the removed implants was performed by scanning electric microscope (SEM). Results  The MRT for the loading implants at 0, 1, 3, and 8 weeks of healing were 4.10, 4.25, 2.42, and 4.42 N·cm, respectively. During the healing process, the removal torque values of the 3-week implants were significantly lower than those of the other healing groups (P<0.05). The unloaded 3-week implants also had lower removal torques (P<0.05). The implant surface of the 3-week test group showed more fibrous bone. However, the other loading implants had more lamellar-like tissue. Conclusion  A stable dangerous period occurred approximately 3 weeks after mini-implant insertion. A 3-week healing is disadvantageous to the stability of the implant. Orthodontics loading occurred immediately or after 1 week as a function of the healing time. The 8-week implant appeared to have a positive effect on peri-implant bone remodeling and implant stability.

    Effects of post-cure heat treatment on the bond strength of Ceramage composite resins for titanium casting using dif-ferent surface treatments
    Liu Jie, Meng Fanyu, Wu Hao2.
    West China Journal of Stomatology. 2013, 31(6):  561-564.  doi:10.7518/hxkq.2013.06.004
    Abstract ( 1057 )   HTML ( 2 )   PDF(pc) (2880KB) ( 670 )   Save
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    Objective  This study aims to investigate the effects of post-cure heat treatment (PCHT) on the bond strength of Ceramage composite resins for titanium casting using different surface treatments. Methods  Metal specimens (n=30) were randomly divided into following five groups: polishing (group A), sandblasting (group B), acid etching after sandblasting (group C), PCHT after sandblasting (group D), and PCHT after sandblasting and acid etching (group E). The specimens were then processed and coated with Ceramage composite resins according to the grouping. After treatment, the shear bond strengths and microhardness of the specimens were evaluated. The fracture surface morphology of the titanium–Ceramage composite resin was observed using a scanning electron microscope. Results  The shear bond strengths of groups A to E were (5.92±0.54), (10.25±0.55), (14.97±0.88), (14.41±0.63), and (19.95±0.52) MPa, respectively. No statistical difference was found between groups C and D, whereas the rest of the groups showed statistically significant differences (P<0.01). Visible polymerization residues were found on titanium porcelain metal surface of groups B to E. The microhardness values of groups D and E were higher than those of groups B and C (P<0.05). Conclusion  PCHT significantly improves the bond strength and surface microhardness of Ceramage composite resins for titanium casting.

    Study on the function of keratinocyte growth factor on apoptosis of oral mucosal epithelial cells
    Wei Meirong, Li Guoju, Zhang Da, Yan Shiguo, Qi Xiangmin.
    West China Journal of Stomatology. 2013, 31(6):  565-568.  doi:10.7518/hxkq.2013.06.005
    Abstract ( 1142 )   HTML ( 2 )   PDF(pc) (1049KB) ( 558 )   Save
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    Objective  To study the function of keratinocyte growth factor (KGF) on apoptosis of oral mucosal epithelial cells and to provide a basis for further investigation of the role of KGF in the occurrence and development of oral mucosal diseases. Methods  Different concentrations of KGF (control group, 0 ng·mL-1; experiment 1 group, 5 ng·mL-1; experimental 2 group, 25 ng·mL-1; experiment 3 group, 50 ng·mL-1) were added in oral mucosa epithelial cells cultured in vitro. After training for 12, 24, and 48 h, cell morphology was observed under an inverted microscope. Apoptosis was detected by using a flow cytometry instrument, and mRNA expression of apoptosis-related genes Bcl-2 and Bax was detected by using Real-Time fluo-rescent quantitative detection. Results  Cell adherence of the experimental group was more obvious than that of the control group, and the cell nucleolus of the experiment 3 group was obviously cultured at 48 h. After culturing for 48 h, the apoptosis rate and Bcl-2 and Bax mRNA expression among the four groups were statistically significant. The increase of KGF concen-tration, apoptosis rate, and Bax mRNA expression gradually reduced, whereas Bcl-2 mRNA expression increased (P<0.05). Conclusion  KGF may inhibit epithelial cell apoptosis through upregulation of Bcl-2 mRNA and downregulation of Bax mRNA.

    Effect of hot chemical etching on bond strength of zirconia to resin
    Dai Wenyong, Yin Houcai, Chen Chen, Xie Haifeng, Zhang Feimin.
    West China Journal of Stomatology. 2013, 31(6):  569-573.  doi:10.7518/hxkq.2013.06.006
    Abstract ( 1387 )   HTML ( 0 )   PDF(pc) (9586KB) ( 1201 )   Save
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    Objective  This study aims to evaluate the influence of hot chemical etching on short- and long-term shear bond strength (SBS) of zirconia to resin. Methods  Eighty zirconia ceramic slices were obtained and randomly divided into five groups based on the surface treatment to be applied—group A: H2SO4/(NH4)2SO4 hot solution etching + application of Clearfil; group B: HF/HNO3 hot solution etching + application of Clearfil; group C: H2SO4/HF/HNO3 hot solution etching + Clearfil; group D: alumina sandblasting + application of Clearfil; group E: tribochemical silica coating + application of silane coupling agent. Eighty composite cylinders were bonded to pretreated ceramic slices using a bis-GMA-based resin cement. Specimens in each group were divided into two fractions: the first half received 24 h water storage, and the second half re-ceived 40 d water storage. Then, SBS tests were conducted. Morphological analysis of sandblasted alumina and hot chemical-etched zirconia surfaces were performed by scanning electron microscopy(SEM). Results  Group E displayed the highest SBS before artificial aging, and no statistical difference was found among the other groups. After 40 d water storage, groups A, B, and E showed significantly higher SBS than groups C and D. SBS increased significantly after artificial aging in groups A and B. No significant variations were found before and after artificial aging in the other groups. Conclusion  The experi-mental hot chemical etching solution provides enhanced bonding for zirconia than sandblasting, and the bond strengths remain stable after artificial aging.

    Foundation of the interactive oral and maxillofacial radiological image annotation database
    Xue Chaoran, Hu Shan-shan, Luo Weijia, Zheng Guangning
    West China Journal of Stomatology. 2013, 31(6):  574-577.  doi:10.7518/hxkq.2013.06.007
    Abstract ( 1098 )   HTML ( 2 )   PDF(pc) (970KB) ( 935 )   Save
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    Objective  This project aims to establish an interactive oral and maxillofacial radiological image annotation database and to analyze its feasibility for implementation into curricula in order to develop a highly effective software for image browsing. Methods  We established the interactive image annotation database primarily on the basis of the local net-work and Foxit Reader. A pilot survey was then conducted to determine the performance of the interactive database. Seventy-six students were asked to complete a structured and open questionnaire related to their perceptions of using the database. Simple numeric quantitative and qualitative analyses were then applied. Results  A total of 542 portable document format (PDF) digital teaching images and corresponding annotated files were collected. The survey revealed that most of the students found the database useful. Approximately 87.50% of the 64 subjects who compelete questionnaire believed that the database was superior to an older system (joint photographic experts group, JPEG) of image browsing. Conclusion  The integration and sharing of teaching resources and the establishment of an internet-based learning platform is the key to realizing a digital medical teaching system. The established database has high potential in a wide range of practical applications.

    Fissure morphology and caries prevalence in the first permanent molars of children in the Dalian development area
    Liu Yijie, Wang Ying, Wu Xiaonan, Wang Meng, Zhao Xiulan, Rong Wensheng
    West China Journal of Stomatology. 2013, 31(6):  578-582.  doi:10.7518/hxkq.2013.06.008
    Abstract ( 1435 )   HTML ( 0 )   PDF(pc) (1311KB) ( 562 )   Save
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    Objective  This study aims to determine the fissure morphology, prevalence, and severity of caries in the first permanent molars of 7-year-old to 9-year-old children in the Dalian development area. The study also aims to investigate the relationship between fissure morphology and noncavitated lesions. Methods  A multi-stage, cluster sampling method was used. Three schools were randomly selected from 20 elementary schools in the Dalian development area. All of the children in the selected schools completed clinical oral examinations. A diagnosis criterion of the International Caries Detection and Assessment System was used to assess the cavitated and noncavitated dental caries in the first permanent molars. Fissure depth and fissure stain were also assessed. Results  The total size of the study sample was 1 160. The prevalence of cavitated caries was 19.1%, and the mean D3-6FT score was 0.31. No significant differences were found between urban and rural sub-jects, between men and women, and among different age groups. The prevalence and D1-2FT score of noncavitated caries were 42.1% and 0.86, respectively. The D1-2FT score for rural children was significantly higher than that for urban children, and the D1-2FT score for girls were higher than that for boys. No statistical differences were found among different age groups. The prevalence of deep fissures in the first permanent molars was 44.7%. The prevalence of noncavitated caries increased with increasing fissure depth. Conclusion  The prevalences of noncavitated caries and deep fissure in the first permanent molars of 7-year-old to 9-year-old children in Dalian were high. Fissure morphology was found to be related to noncavitated caries.

    Perioperative nursing of internal sinus floor elevation surgery with piezosurgery
    He Jing, Lei Yiling, Wang Liqiong
    West China Journal of Stomatology. 2013, 31(6):  583-584.  doi:10.7518/hxkq.2013.06.009
    Abstract ( 1148 )   HTML ( 2 )   PDF(pc) (919KB) ( 786 )   Save
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    Objective This study aims to summarize the nursing experience in the internal sinus floor elevation surgery with piezosurgery. Methods The medical records of 48 patients who underwent sinus floor elevation surgery with piezosur-gery in the Department of Implantation, West China Hospital of Stomatology, Sichuan University, were reviewed. The pre-operative, intraoperative, and postoperative nursing methods were summarized. Results All 48 patients underwent smooth surgeries and did not encounter complications. Conclusion Careful preoperative preparation, careful and meticulous intra-operative nursing cooperation, and provision of sufficient health education after surgery to the patients are the key factors that ensure the success of internal sinus floor elevation surgery with piezosurgery.

    Assessment of occlusal vertical dimension using angles: a pilot study
    Zhou Niangou, Zeng Liwei, Jiao Jilan, Deng Lu, Chen Ping
    West China Journal of Stomatology. 2013, 31(6):  585-587.  doi:10.7518/hxkq.2013.06.010
    Abstract ( 1081 )   HTML ( 1 )   PDF(pc) (1270KB) ( 598 )   Save
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    Objective  This study aims to identify highly accurate quantitative methods for evaluating the occlusal vertical dimension by using cephalometric radiographs to analyze the craniofacial hard tissue landmarks in 30 cases with normal occlusions. Methods  A total of 30 subjects with normal occlusions and aged between 20 and 30 years old were included in the study. Cephalometric radiographs were obtained and analyzed using the Winceph 8.0 measurement software. Landmark points were identified and measured. Results  The mean distribution difference of the center angle (CA) and lower angle (LA) of the face was not statistically significant (t=-1.490, P=0.147). The CA and LA had a significantly linear correlation (r=0.976, P=0.000), and the regression equation was y=0.298+0.997x. Conclusion  The CA can be used to assess and quan-tify the occlusal vertical dimension in clinical practice.

    Application of cone-beam computed tomography in the diagnosis and treatment of external root resorption of adja-cent teeth caused by impacted teeth
    Li Zhijin, Guo Jiaping, Shi Yongmei, Dong Qingshan, Wang Xiang, Xiong Caihua, Gui Xiao
    West China Journal of Stomatology. 2013, 31(6):  588-591.  doi:10.7518/hxkq.2013.06.011
    Abstract ( 1459 )   HTML ( 3 )   PDF(pc) (3523KB) ( 777 )   Save
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    Objective  This study aims to investigate the diagnosis and treatment of external root resorption of adjacent teeth caused by impacted teeth via cone-beam computed tomography (CBCT). Methods  A total of 19 teeth from 15 patients with uncertain external root resorption caused by an adjacent impacted tooth were examined from January 2011 to December 2011. All teeth with uncertain external root resorption were scanned by CBCT. Three dimensions reconstruction were the con-ducted to determine the location and extent of resorption. Results  In all cases, CBCT identified the accurate location and extent of external root resorption caused by adjacent impacted teeth. Furthermore, the technique provided impacted teeth location in three dimensions, including the relation between the impacted teeth and surrounding vital structures. Conclusion  CBCT can provide direct and accurate images of the location and extent of external root resorption, as well as the location of the adja-cent impacted teeth in three dimensions. Therefore, the proposed technique provides reliable information for clinical diagnosis and treatment.

    Minocycline hydrochloride liposome controlled-release gel improves rat experimental periodontitis
    Liu Di1, Yang Pishan, Hu Deyu, Liu Fuxiang
    West China Journal of Stomatology. 2013, 31(6):  592-596.  doi:10.7518/hxkq.2013.06.012
    Abstract ( 2307 )   HTML ( 4 )   PDF(pc) (8831KB) ( 973 )   Save
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    Objective  To evaluate the therapeutic effects of 2% minocycline hydrochloride liposome controlled-release gel on the periodontitis in an established rat periodontitis model. Methods  Biocompatibility was tested by oral perfusion sample solution for long-term observation. Minocycline hydrochloride liposome controlled-release gel was utilized to treat the established rat periodontitis model. The rats were selected randomly and divided into three groups: group A (PERIO-treated group), group B (minocycline hydrochloride liposome controlled-release gel treated group), and group C (negative control group). The gingival index (GI) and probing depth (PD) were detected, and the number of mononuclear and broken bone cells were examined after 7, 14, 28, and 56 d. Results  The minocycline hydrochloride liposome controlled-release gel exhibited excellent biocompatibility based on weight measure and tissue section evaluation. The rats with periodontitis demonstrated that GI, PD, and the number of mononuclear and broken bone cells of group B decreased in 14, 28, and 56 d. Pathological observation showed that new bones and fibers were formed in group B. Conclusion  Minocycline hydrochloride liposome controlled-release gel improves rat periodontitis, thereby providing valuable evidence for clinical application.

    Effect of infiltration resin on the color masking of labial enamel white spot lesions
    Feng Chaohua, Liu Rongfang, Zhao Qi, Chu Xiaoyu
    West China Journal of Stomatology. 2013, 31(6):  597-599.  doi:10.7518/hxkq.2013.06.013
    Abstract ( 2561 )   HTML ( 9 )   PDF(pc) (3945KB) ( 882 )   Save
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    Objective  To evaluate the effect of infiltration resin on masking white spot lesions by assessing the change in the white spot area. Methods  Seventy-four maxillary anterior teeth with post-orthodontic decalcification teeth were investi-gated in this study. All teeth were treated with infiltration resin according to manufacturer recommendation. Standardized digital images were taken before, immediately after, and one week after treatment. The results were classified into three groups: com-pletely masked, partially masked and unchanged. The images of partially masked teeth were analyzed using an image analysis software. The size of the white spot lesion (W) and the whole-tooth facial surface (T) were measured, and the W︰T ratio(%) was calculated. Statistical evaluation of the lesions was performed using Kruskal–Wallis and Mann–Whitney tests. Results  Among the 74 teeth, 20 (27%) teeth were classified as completely masked and 54 (73%) teeth were classified as partially masked; no tooth was unchanged. The W︰T ratio significantly decreased from 39.28% before treatment to 9.46% after treat-ment (P<0.05). Conclusion  Resin infiltration is an effective treatment for masking white spot lesion. However, the masking effect depends on the lesion depth and activity.

    Evaluation of root resorption after palatal expansion by magnetic expansion appliance
    Ma Qiaoling, Wang Tiemei, Wu Tuojiang, Liu Shu, Li Huang
    West China Journal of Stomatology. 2013, 31(6):  600-604.  doi:10.7518/hxkq.2013.06.014
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    Objective  To investigate the root length of posterior teeth after palatal expansion by magnetic expansion ap-pliance. Methods  A total of 32 patients who accepted palatal expansion with magnetic expansion appliance were enrolled in the study. Pretreatment and post-treatment cone-beam computed tomography (CBCT) images were obtained. A paired t test was used to evaluate the length change, and a group t test was used to compare the tooth lengths of developing and developed teeth. Results  Anchorage teeth showed greater root resorption than non-anchorage teeth, whereas the developed posterior teeth showed reduced resorption. Moreover, the mesial buccal roots of the first molar and first premolar were reduced. No resorption was found in the developing teeth group. Conclusion  The magnetic palatal expansion can reduce the root length, particularly of developed root. The developing root of anchorage teeth show greater tolerance to resorption than the developed root. Early palatal expansion treatment with magnetic expansion appliance can reduce the risk of root resorption.

    Three-dimensional evaluation of the relationship between dental and basal arch forms in skeletal class Ⅱ malocclu-sions
    Wu Jiaqi, Jiang Jiuhui, Zou Wei, Xu Tianmin, Liu Xuezong
    West China Journal of Stomatology. 2013, 31(6):  605-609.  doi:10.7518/hxkq.2013.06.015
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    Objective This study aims to investigate the relationship between the dental and basal arch forms of patients with skeletal class Ⅱ malocclusion using three-dimensional virtual models and to generate the best-fit curve for these arch forms. Methods  The mandibular dental casts of 35 skeletal class Ⅱ patients were taken prior to treatment and were laser scanned. The facial axis (FA) points, which were used to represent the dental arch, and the WALA points, which were used to represent the basal bone, were identified for each tooth from the right first molar to the left first molar. The Pearson corre-lation coefficients between the intercanine and intermolar widths at the FA and WALA points were determined. Finally, the best-fit curves were generated using the fourth-degree polynomial equation to represent the arch forms. Results  A strong correlation was found between the FA and WALA intermolar widths (r=0.873). However, a moderate correlation was observed between the FA and WALA intercanine widths (r=0.534). The difference between the intermolar widths at the FA and WALA points was significant (P<0.01). No statistically significant difference was found between the intercanine widths (P=0.481). The radii of curvature of the FA and WALA curves in the anterior teeth area were 15.194 and 20.250, respectively. The re-gression coefficients of the FA and WALA curves were calculated as R2=0.912 and 0.947, respectively. Conclusion For skeletal class Ⅱ malocclusion patients, the FA and WALA dental intermolar widths showed strong correlation, whereas the FA and WALA intercanine widths exhibited moderate correlation. The FA points were located more labially in the anterior teeth area but more lingually in the posterior teeth area. No statistically significant difference was found between the intercanine FA and WALA widths. The difference between the intermolar widths at the FA and WALA points was significant. The radii of curvature of the FA curve was larger than that of the WALA curve in the anterior teeth area.

    Cone-beam CT evaluation of the changes in the temporomandibular joint of patients with class Ⅱ division 1 subdivi-sion malocclusion before and after Twin-block treatment
    Liu Bowen, Wang Yanmin, Song Fang, Liu Min, Duan Ying, Zhou Li
    West China Journal of Stomatology. 2013, 31(6):  610-614.  doi:10.7518/hxkq.2013.06.016
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    Objective  This study aims to evaluate the temporomandibular joint (TMJ) changes in patients with class Ⅱ division 1 subdivision malocclusions before and after Twin-block treatment using a cone-beam CT (CBCT). Methods  Twenty subjects with class Ⅱ division 1 subdivision malocclusions were included in this study. Hand-wrist radiographs were conducted in the FG-G stage. CBCT was performed to determine the changes in the TMJ before and after the Twin-block treatment. The InVivoDental software was used to calculate the relevant parameters from the three-dimensional CBCT images. The acquired data were then analyzed. Results After treatment, the sagittal condylar anterior spaces were reduced, whereas the sagittal condylar superior and posterior spaces as well as the coronal condylar superior space increased (P<0.01). The condylar height, sagittal condylar angles, and condylar anteroposterior diameters also increased (P<0.01). Conclusion After the Twin-block treatment, new bone deposition was observed on the condyle. The condyle height also increased and resulted in adjustments in the condyle position within the glenoid fossa to more downward and forward positions. CBCT can quantify TMJ changes and provide an objective assessment to orthodontic treatment.

    Exploring the relationship between secreted frizzled-related protein 1 and chronic periodontitis
    Yuan Haibo, Jin Jing, Xu Chunjiao, Qiu Xili, Wang Lu, Lü Fengyuan, Liu Tingting, Wu Yingfang, Yin Xiaomin, Fang Changyun, Que Guoying, Peng Jieying
    West China Journal of Stomatology. 2013, 31(6):  615-618.  doi:10.7518/hxkq.2013.06.017
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    Objective  This study detects the expression of secreted frizzled-related protein 1 (SFRP1) in healthy patients and patients with chronic periodontitis (CP) and explores the relationship between SFRP1 and the occurrence and development of CP. Methods  First, 28 patients forming the CP group were further divided into mild, moderate, and severe CP subgroups according to clinical attachment loss (CAL) data. Ten healthy volunteers were recruited in the control group. Gingival crevi-cular fluid (GCF) was collected from all of the patients, and the concentration of SFRP1 in the GCF samples was detected using enzyme-linked immunosorbent assay. Next, gingival lesions were obtained from 22 patients in the CP group and healthy gingival tissues were obtained from the 10 healthy patients in the control group. Immunohistochemical analysis for SFRP1 was used to analyze the correlation between the expression of SFRP1 and the severity of CP based on staining intensities. Results  The concentration of SFRP1 in GCF samples taken from of the CP group (281.07 ng·L-1±33.37 ng·L-1) was signifi-cantly higher than that in samples taken from the control group (245.30 ng·L-1±35.69 ng·L-1) (P<0.05). A significant positive correlation was observed between the concentration of SFRP1 in GCF and CAL (r=0.651, P<0.001). Furthermore, the SFRP1 scores in the CP groups (4.500±0.913) were significantly higher than those in the control group (2.800±1.135) (P<0.001). SFRP1 scores did not vary significantly among the CP subgroups (P>0.05). Conclusion  SFRP1 expression in the CP groups was significantly higher than that in the control group. Thus, SFRP1 may play a significant role in the development of CP.

    Quantitative analysis of Streptococcus mutans and its proportion in the dental plaque of different caries-susceptible children
    Zhao Hechuan, Chen Xiaochi, Xu Tao
    West China Journal of Stomatology. 2013, 31(6):  619-623.  doi:10.7518/hxkq.2013.06.018
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    Objective  To determine the quantity of Streptococcus mutans (S. mutans) and the ratio of S. mutans to total bacteria in the dental plaque of different caries-susceptible children. Methods  Dental plaque samples from 26 children aged 3 years old to 4 years old were collected. The quantities of S. mutans and total bacteria were determined by TaqMan real-time fluorescence quantitative polymerase chain reaction (PCR). The ratio of S. mutans to total bacteria in children with and without caries was calculated and statistically analyzed. Results  In children with and without caries, the quantities of S. mutans were 1.33×105 and 1.16×103 CFU·mg-1, the total bacteria were 7.17×107 and 1.01×108 CFU·mg-1, and the ratios of S. mutans to total bacteria were 0.058 6 and 0.018 6, respectively. Significant differences were observed in the quantities of S. mutans and the total bacteria as well as in the ratios of S. mutans to total bacteria of the two groups (P=0.033, 0.418, 0.008). Conclusion  The quantities of total bacteria of the two groups show negligible difference. However, the quantity of S. mutans and the ratio of S. mutans to total bacteria in caries-susceptible children are higher than those in caries-free children. Therefore, the ratios of S. mutans to total bacteria in plaque are closely associated with the prevalence of dental caries in children.

    Impression technique with a tissue-stop area for type four edentulous jaws
    Liu Jianzhang, Guo Qiyan, Zou Wen
    West China Journal of Stomatology. 2013, 31(6):  624-627.  doi:10.7518/hxkq.2013.06.019
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    Objective  This study aims to develop a mandibular impression technique for type four edentulous jaws. Methods  Twenty patients with type four edentulous jaws were selected for this study. The mandibular impression for each patient was made using both a traditional impression technique and the impression technique with a tissue-stop area. After the cast was made for each impression, the temporary denture bases were constructed on each cast. When the patients wear temporary denture bases, they must appreciate the degree of comfortability provided by each denture base. Whether the soft tissues that had been pushed away was also recorded. For 10 of the randomly selected patients, a complete denture was made using the traditional impression technique; the remaining ten subjects were given complete dentures constructed by the im-pression technique with a tissue-stop area. The number of times a review for misfit was recorded. The tissue fitness of each denture was also recorded. Results  A paired t-test showed that the soft tissues that stacked on the residual ridge were more readily pushed away by the impression technique with a tissue-stop area than by the traditional impression technique. However, for all patients, the degree of comfortability did not vary when different techniques were used. The independent t-test results indicated that the differences between the fitness of dentures constructed using different impression techniques were not signi-ficant. The number of times a review for misfit conducted by the impression technique with a tissue-stop area was considerably lower than that for patients wearing traditionally dentures. Conclusion  Using the impression technique with a tissue-stop area can more readily push away the soft tissues packed on the residual ridge and reduce the times of review for misfit com-pared with using the traditional technique. However, the degree of comfortability and fitness of denture are not improved.

    Effects of estrogen on the proliferation and differentiation of human embryo mandibular condylar chondrocytes
    Pang Lei, Zhang Yuerong, Liu Zhonglin
    West China Journal of Stomatology. 2013, 31(6):  628-632.  doi:10.7518/hxkq.2013.06.020
    Abstract ( 995 )   HTML ( 0 )   PDF(pc) (12804KB) ( 721 )   Save
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    Objective  To determine the effects of different estrogen concentrations on the proliferation and differentiation of human embryo mandibular condylar chondrocytes (MCCs). Methods  In vitro-cultured MCCs were incubated and treated with estrogen at different concentrations. The MCCs were identified by toluidine blue and type Ⅱ collagen immunocytoche-mical methods, and cell proliferation was monitored using methyl thiazolyl tetrazolium assay. Results  The addition of 10-12 or 10-6 mol·L-1 exogenous estrogen inhibited the growth of MCCs, whereas addition of 10-10 or 10-8 mol·L-1 exogenous estrogen promoted growth. These estrogen effects were time-dependent. Conclusion  Estrogen can affect cellular MCCs proliferation and differentiation in a biphasic manner depending on the concentration. Estrogen may be vital in the maintenance of normal functions of the temporomandibular joint (TMJ) and may be involved in the progression of certain TMJ diseases.

    Establishment of maxillary anterior teeth computer simulation restoration system
    Zhang Genxiang, Yang Ying.
    West China Journal of Stomatology. 2013, 31(6):  633-637.  doi:10.7518/hxkq.2013.06.021
    Abstract ( 2142 )   HTML ( 8 )   PDF(pc) (5402KB) ( 989 )   Save
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    Objective  This study aims to simulate restoration of anterior teeth appearance by using three-dimensional (3D) reconstruction technique combined with computer image processing and 3D animation software. Methods  The standard teeth model was scanned by cone beam CT, and the standard teeth model database was established. Using Windows XP, the language system of Microsoft Visual C++6.0 was used. Based on MS SQL SERVER2000, the maxillary anterior teeth computer simulation restoration system was developed with a 3Ds Max core. The system was used to simulate the rehabilita-tion of maxillary anterior teeth in the clinical setting. Results  The maxillary anterior teeth computer simulation restoration system was easy to operate, and the simulation results were reliable. Conclusion  The maxillary anterior teeth computer simulation restoration system can help patients understand treatment designs. The system provides an effective means of creating patient-desired dental prosthesis with personalized characteristics.

    Maxillary anterior tooth restoration by using fiber-reinforced composite with a natural tooth pontic: a case report
    Xu Mengrong, Zhang Qian, Qiu Haiyan
    West China Journal of Stomatology. 2013, 31(6):  638-640.  doi:10.7518/hxkq.2013.06.022
    Abstract ( 1325 )   HTML ( 1 )   PDF(pc) (4670KB) ( 1168 )   Save
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    Loss of anterior tooth impairs patients physically and emotionally as well as presents a challenge for dentists. This article presented a method of replacing one anterior tooth that was extracted because of periodontitis. The proposed method involves the use of the natural crown as pontic with fiber-reinforced composite resin-bonded fixed partial denture.

    Root canal treatment of two-rooted three-canal maxillary first premolar: a case report
    Xie Kexian, Wang Xiao, Li Yuangao, Zhang Ping
    West China Journal of Stomatology. 2013, 31(6):  641-643.  doi:10.7518/hxkq.2013.06.023
    Abstract ( 1383 )   HTML ( 11 )   PDF(pc) (3685KB) ( 1187 )   Save
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    According to literature, the incidence of three-canal maxillary first premolar is between 0.5% and 7.5%. The two types of three-canal maxillary premolars are two-rooted and three-rooted three-canal maxillary premolars. Most case reports in Chinese literature focus on three-rooted three-canal maxillary premolars. To our knowledge, no domestic case report on two-rooted three-canal maxillary premolar has been published. In this study, we describe the root canal treatment of a two-rooted three-canal maxillary premolar.

    Application of adipose-derived mesenchymal stem cells in craniomaxillofacial restoration and reconstruction
    Shu Mingyang, Liu Lei.
    West China Journal of Stomatology. 2013, 31(6):  644-647.  doi:10.7518/hxkq.2013.06.024
    Abstract ( 970 )   HTML ( 2 )   PDF(pc) (1043KB) ( 722 )   Save
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    Craniomaxillofacial hard and soft tissue defects are clinically common and frequently encountered diseases that seriously affect the appearance and function of patients. Restoration and reconstruction of craniomaxillofacial hard and soft tissues are comprehensive clinical problems that require a multi-disciplinary approach and are faced with many unre-solved issues. Development of tissue engineering has introduced new concepts to craniomaxillofacial restoration and recon-struction. Tissue engineering primarily aims to determine suitable seed cells. Recently, adipose-derived mesenchymal stem cells (AdSCs) were found to be relatively ideal seed cells because they are easy to obtain from numerous sources and have multiple potencies under certain inducing circumstances and high augmenting ability. This review provides an overview of the application of AdSCs in craniomaxillofacial restoration and reconstruction.