Shanghai Journal of Stomatology

Repair of calvarial defect using a tissue-engineered bone with simvastatin-loaded β-tricalcium phosphate scaffold and adipose derived stem cells in rabbits

XU Lian-yi, SUN Xiao-juan, ZHANG Xiu-li, JIN Yu-qin, WU Yu-qiong, JIANG Xin-quan

2013, 22 (4): 361-367.

Abstract ( 344 )

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PURPOSE: The osteogenic-angiogenic differentiation effects of simvastatin (Sim) were explored on adipose tissue-derived stem cells (ASCs). A tissue-engineered bone with simvastatin loaded β-tricalcium phosphate (β-TCP) scaffold and ASCs was constructed to repair the calvarial defect in rabbits. METHODS：ASCs were obtained from the groin of rabbits. After 14 days of osteogenic inducing culture, sufficient cells were expanded for the following experiments. Cell counting was conducted to ASCs in osteogenic inducing medium containing 0, 0.01, 0.1 and 1 μmol/L simvastatin. Concentrations of 0.05 and 0.1 μmol/L simvastatin were administrated to ASCs for real-time PCR of angiogenesis-osteogenesis related genes like RUNX2, OPN, OCN, and VEGF on day 1, 7. ALP staining was performed on day 7, Alizarin red staining for calcium deposits was carried out on day 14. Bilateral critical-sized defects were created on 12 New Zealand rabbits. Four groups of tissue-engineered bone were randomly allocated to them. Group A: β-tricalcium phosphate (β-TCP) (n=6); group B: β-TCP/Cell (n=6); group C: β-TCP/Sim (n=6); group D: β-TCP/Cell/Sim (n=6). Specimens were decalcified and stained by HE 8 weeks after operation. The data was statistically analyzed using SPSS 17.0 software package. RESULTS: The use of simvastatin with the concentration of 0.05 μmol/L enhanced the expression of angiogenic-osteogenic related genes like RUNX2, OPN, OCN, and VEGF. ALP activity and von Kossa were significantly stronger in osteogenic inducing medium containing 0.05 μmol/L simvastatin. The new bone formation area of β-TCP/Cell/Sim group at 8-week after implantation was significantly larger than the other groups. CONCLUSIONS: 0.05 μmol/L simvastatin enhances the angiogenic-osteogenic differentiation of ASCs. Simvastatin loaded β-TCP scaffold and ASCs successfully repair the calvarial defect in rabbits. These results indicate a promising future in application of simvastatin for bone regeneration.

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Osteoclasts and early bone remodeling after orthodontic micro-implant placement

ZHANG Wei, GUO Jia-jia, ZHU Wen-qian, TANG Guo-hua

2013, 22 (4): 368-373.

Abstract ( 469 )

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PURPOSE: To observe the incidence of osteoclasts during early bone remodeling after orthodontic micro-implant placement. METHODS：Twenty New Zealand rabbits were randomly allotted into 4 groups. One micro-implant was implanted proximal to the epiphyseal plate of the tibia. Animals were sacrificed on day 3, 7, 14 and 28 (n=5). The sequence of histological changes around the micro-implants were evaluated by hematoxylin and eosin (HE) staining. Osteoclasts were identified by TRAP staining. The differences of the number of the osteoclasts among each time point were analyzed by one way ANOVA with SPSS 19.0 software package. RESULTS: After 3 days of implantation, a large number of erythrocytes, inflammatory cells, mesenchymal cells and bone debris were seen at the implant bone interfaces. Few osteoclasts were observed. On day 7, granular woven bone was formed and some osteoclasts were found in the Howship’s lacunae. New bone formation and mineralization were apparent on day 14. Meanwhile, large amounts of osteoclasts were found in the latticed woven bone. On day 28，woven trabeculae with lamellate structures connected to lamellar bone and fewer osteoclasts were identified. Semi-quantitative analysis showed that the number of the osteoclasts was at peak on day 14. There were significant differences among each time point (P<0.01). CONCLUSIONS: Osteoclast activity is closely related to bone formation and remodeling after micro-implant insertion.

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Three-dimensional finite element analysis of the upper cervical-defected incisor with labial access or lingual access

SU Fan, ZHAO Ying, SU Qin

2013, 22 (4): 374-377.

Abstract ( 257 )

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PURPOSE: To evaluate the stress distribution of the cervical-defected incisor with labial or lingual endodontic access with finite element analysis (FEA), and to explore the advantage of resistance in labial endodontic access. METHODS: 3-D finite element models of upper cervical-defected incisor were established using cone-beam CT (CBCT), Mimics Catia, and Ansys software. The subjects were categorized according to the two endodontic accesses and three restorative ways, which were composite resin, glass fiber-reinforced composite resin and glass fiber-reinforced post-crown. All the models were loaded.The von Mises stress values and distribution were recorded and analyzed with Ansys 10.0 software. RESULTS: In this study, direct composite resin restoration showed no significant difference between the labial and lingual access. In glass fiber-reinforced composite resin, labial access could transfer the stress concentration area. It could reduce the incidence of fracture of the cervical lesion but increase the incidence of root fracture. Post-crown restoration could obviously reduce the incidence of fracture of the cervical lesion. CONCLUSIONS: When the cervical-defected incisor is restored with composite resin, labial and lingual accesses can be considered. Labial access with glass fiber-reinforced composite resin or post-crown restoration is a good choice.

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Effect of NF-κB on the expression of interleukin-6 induced by lipopolysaccharides of Porphyromonas endodontalis in MC3T3-E1 cells

YU Ya-qiong, GUO Jia-jie, QIU Li-hong, LV You, JIA Ge, GUO Yan

2013, 22 (4): 378-383.

Abstract ( 223 )

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PURPOSE: To investigate the effect of NF-κB signaling on the expression of interleukin-6(IL-6) induced by lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e)in MC3T3-El cells. METHODS: MC3T3-E1 cells were pretreated with BAY-117082 for 1 h, and then were treated with 10 mg/L P.e-LPS for different times. The translocation of NF-κB was observed by immunofluorescence. The expression of IL-6 was detected by reverse transcription polymerse chain reaction (RT-PCR) and enzyme-linked immuno sorbent assay (ELISA). Statistical analysis was performed using multi-way ANOVA and Dunnett’s t test with SPSS 13.0 software package. RESULTS: The staining of NF-κB was mostly in cytoplasm in untreated cells. Rapid translocation of NF-κB into nucleus was observed in the cells stimulated for 30 min and mostly relocalization of NF-κB from nucleus to cytoplasm was observed after 60 min. Pretreatment with 10 μmol/L BAY-117082 for 1h significantly inhibited P.e-LPS-induced translocation of NF-κB .The mRNA and proteins of IL-6 decreased significantly after pretreatment with 10 μmol/L BAY-117082，and the expression of IL-6 proteins was reduced from (774.983±6.585) ng/L to (377.384±14.620) ng/L (P<0.01). The group of treatment with BAY-117082 alone had no significant difference from the blank control group. CONCLUSIONS: P.e-LPS can induce translocation of NF-κB in mouse osteoblast MC3T3-El, and P.e-LPS may induce the expression of IL-6 in mouse osteoblast through the signaling of NF-κB.

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Dynamic analysis of the rigid fixed bridge and related tissue after intrusion of abutment with micro screw implant

ZHU Lin, XU Pei-cheng, LU Liu-lei

2013, 22 (4): 384-388.

Abstract ( 208 )

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PURPOSE: To study the variety of mechanical behavior of fixed bridge after abutments being intruded by micro screw implant and to provide theoretical principles for clinical practice of teeth preparation after intrusion of abutments under dynamic loads. METHODS: Two-dimensional images of maxilla, teeth and supporting tissues of healthy people were scanned by spiral CT and were synthesized by Mimics10.01, Ansys13.0, etc. The three-dimensional finite element mathematical model of rigid fixed bridge repairing on double end of maxillary molar was developed. Under the condition of 10% simulative abutment alveolar absorption, vertical and oblique dynamic forces were applied in a circle of mastication(0.875 s) to build mathematical model after the abutment had been intruded for 0.5, 1.0, 1.5 and 2.0 mm. Stress variety of prosthesis, teeth, periodontal ligaments and supporting tissues were compared before and after intrusion of abutments. RESULTS: Stress variety of the prosthesis occurred, which had close relationship with the structure of prosthesis and teeth, the areas of periodontal ligaments increased, stress on the whole decreased along with the increase of the length of intrusion. With time accumulating, the stress value in prosthesis, teeth, periodontal ligaments and supporting tissues increased gradually and loads in oblique direction induced peak value stress in a masticatory cycle. Some residual stress left after unloading. CONCLUSIONS: By preparing the fixed bridge after abutment intrusion by micro screw implant, the service life of abutment and fixed bridge prosthesis can be reduced. The abutment and its related tissue have time-dependent mechanical behaviors during one mastication. The influence of oblique force on stress was greater than vertical force. There is some residual stress left after one mastication period. With the increase of the intrusion on abutment, residual stress reduced.

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Use of recombinant human beta-defensin-3 to evaluate the effect of adhesion of Candida albicans on the surface of soft lining material

SHI Yong, SONG Wei, LIU Xiao-fang, GAO Li-min, SONG Guang-bao

2013, 22 (4): 389-392.

Abstract ( 293 )

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PURPOSE: To evaluate the effectiveness of recombinant human beta-defensin-3 (rHBD3) on reduction of Candida albicans from the surface of soft lining materials. METHODS: Specimens made of soft lining materials, which had been contaminated with C. albicans, were immersed in 25 μg/mL rHBD3 and 5.25% sodium hypochlorite (a positive control) for 5, 10, 30 and 60 min. The results were analyzed statistically with SPSS 10.0 software package. Confocal laser scanning microscopy(CLSM) of biofilm-associated C. albicans were treated with rHBD3 in different times. RESULTS: The results confirmed that an immersion time of 30 min or higher yielded a good disinfection effect, both for the experimental group and the positive control. A large number of pathogenic bacteria were killed and the cells were stained red by SYTO9/PI after 30 min. CONCLUSIONS: It is possible that soft lining materials immersed in rHBD3 solution that possesses antifungal activity may be clinically protective.

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Three-dimensional finite element stress analysis of mandibular first molar with single and combined crowns after separation prosthodontic therapy

WANG Tao, LI Ke, QIU Xiao-xia, ZHOU Lin, MO San-xin

2013, 22 (4): 393-398.

Abstract ( 359 )

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PURPOSE: To evaluate the influence of two kinds of fixed prosthesis on the stress of the mandibular first molar with separation prosthodontic therapy. METHODS: A 3-D finite element model of the mandibular first molar was established with single and combined crowns and their supporting tissues by means of cone-beam CT (CBCT) scanning technology and software Mimics, Geomagic, UG of image processing program. Under dispersed vertical load and dispersed oblique load, the stresses of dental tissues and periodontium were obtained and analysed. RESULTS: When dispersed vertical load was applied, the dental and periodontal stress distribution of two models were similar to the normal. The dental stress value and maximum tensile stress of the periodontal membrane increased and changed greatly in the single crown. When dispersed oblique load was applied, the model of combined crown was similar to the normal. The stress concentrated area expanded in the distal root of the single crown model and the buccal bottom half of the periodontium. The dental stress value and maximum tensile stress of the periodontal membrane increased and changed greatly in the single crown. CONCLUSIONS: The combined crown is a better choice for restoration of mandibular first molar after separation prosthodontic therapy.

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Experimental evaluation of the spraying disinfection efficiency on dental models

ZHANG Yi, FU Yuan-fei, XU Kan

2013, 22 (4): 399-401.

Abstract ( 426 )

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PURPOSE: To evaluate the disinfect effect after spraying a new kind of disinfectant on the dental plaster models. METHODS: The germ-free plaster samples, which were smeared with bacteria compound including Staphylococcus aureus, Escherichia coli, Saccharomyces albicans, Streptococcus mutans and Actinomyces viscosus were sprayed with disinfectants (CaviCide) and glutaraldehyde individually. In one group(5 minutes later) and another group(15 minutes later), the colonies were counted for statistical analysis after sampling, inoculating, and culturing which were used for evaluation of disinfecting efficiency. ANOVA was performed using SPSS12.0 software package. RESULTS: All sample bacteria were eradicated after spraying disinfectants(CaviCide) within 5 minutes and effective bacteria control was retained after 15 minutes. There was significant difference between the disinfecting efficiency of CaviCide and glutaraldehyde. CONCLUSIONS: The effect of disinfection with spraying disinfectants (CaviCide) on dental models is quick and effective.

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Effect of infiltration technique and polishing on the roughness of artificial carious enamel surfaces

YUAN Chang-qing, DOU Guo-wen, DENG Jing, GENG Guo-liang, SUN Pei, CAO Ying-xiu

2013, 22 (4): 402-406.

Abstract ( 178 )

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PURPOSE: To study the surface roughness of early carious lesions which were treated with resin infiltration and polished with different materials, and to provide reference for selection of appropriate polishing system. METHODS: Fifty-four labial surface specimens of mandibular incisors were created out of bovine teeth. They were randomly divided into 6 groups. One group was sound enamel group. Another group was early enamel carious group. Other specimens were treated with a partially saturated acidic buffer solution for preparation of initial artificial enamel caries. These initial artificial enamel caries were treated with resin infiltration. Then they were randomly divided into 4 groups according to polishing or not and type of polishing tool (rubber cups, polishing discs, HiLuster polishers). The surface roughness of specimens in all groups were measured with Form Talysurf PGI 800. Arithmetical mean deviation of the assessed profile (Ra) and the maximum height of the profile(Rz) were used as measurement parameter. SPSS 17.0 software package was used for data analysis. RESULTS: Comparison of sound enamel surfaces and early carious surfaces revealed no significant difference in surface roughness(P>0.05), but the mean value of the latter one was higher. After infiltration, the roughness of surfaces without polishing was significantly higher than that of early carious surfaces(P<0.05). After infiltration and polishing with different tools, there was no significant difference in surface roughness of every two groups (P>0.05). The roughness of polishing groups after infiltration was significantly smaller than that of group without polished after infiltration (P<0.05). Comparison of polishing surfaces after infiltration and early carious surfaces revealed no significant difference in surface roughness (P>0.05). CONCLUSIONS: After early caries being treated with infiltration technique, the roughness of teeth surfaces increases significantly. Those surfaces should be polished. Rubber cup and polishing discs with smaller granularity are more effective and reasonable as the surface polishing materials.

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The influence of Co-Cr-Mo alloys on biological behaviour of L929 mouse fibroblasts

ZHOU Qun, MIAO Lei, FENG Jing-wen, YU He-dong, GUO Lei, LIN Xiao-ping

2013, 22 (4): 407-413.

Abstract ( 288 )

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PURPOSE: To investigate the influence of dental Co-Cr-Mo alloys on biological behaviour of L929 mouse fibroblasts. METHODS: Leaching liquor of medical pure titanium, Co-Cr-Mo alloys, Co-Cr alloys and Ni-Cr alloys was prepared and used to culture the L929 cells for 24 h, 48 h and 72 h, respectively; then the growth of L929 cells was observed under inverted phase contrast microscope, and the cytotoxicity grades of 4 kinds of materials were evaluated by using CCK-8 test. The apoptosis of L929 cells was measured by flow cytometry(FCM) and acridine orange staining was used to observe the L929 cells adhered on the surface of samples under fluorescent microscope. The data was statistically analyzed with SPSS17.0 software package. RESULTS: Under inverted phase contrast microscope, at each time point, L929 cells grew in a good condition except in the Ni-Cr alloys group that minor karyopyknosis was indicating slight celluar cytotoxicity. Optical density (OD), apoptosis rate and cell adhesion number in Co-Cr-Mo alloys group at each time point were significantly less than in medical pure titanium group (P<0.05), and higher than in Co-Cr alloys group (P<0.05) and Ni-Cr alloys group (P<0.05). During observation period, the cytotoxicity grades of medical pure titanium group, Co-Cr-Mo alloys group and Co-Cr alloys group was grade 1, while Ni-Cr alloy group was grade 2, i.e. mild cytotoxicity. CONCLUSIONS: Co-Cr-Mo alloys have no adverse effect on the biological behavior of L929 cells, which may be suitable for dental clinical application with good biocompatibility.

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Effects of composite resin and glass-ionomer cements on proliferation and functional activity of human macrophages

GONG Yu, YANG Rong-qiang, YANG Hong-li

2013, 22 (4): 414-417.

Abstract ( 203 )

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PURPOSE: To study the effects of composite resin and glass-ionomer cements on cell proliferation and function of human macrophages in vitro. METHODS: Macrophages were differentiated from THP-1 cells after treatment with phorbol ester and used as the model of inflammatory cells, which were treated by specimens from glass-ionomer cements(GC), composite resin Filtek Z350(3M)and Filtek P60(3M) on culture medium for 24 hours. The cell proliferation of the tooth-colored restorative materials on human macrophages in vitro was evaluated by MTT color imetric assay, and determined for IL-1 content in these material specimens by ELISA.All statistical analyses were performed using the SPSS 17.0 software package. RESULTS: Compared with control group, composite resin Filtek Z350(3M) and Filtek P60(3M) significantly enhanced the proliferation of human macrophages (P<0.05), while Glass-ionomer had little effect on the proliferation of human macrophages (P>0.05). Glass-ionomer could promote macrophages to secrete IL-1β and the difference was statistically significant(P<0.05). The composite resin could not cause release of IL- 1β from macrophages (P>0.05). CONCLUSIONS: Composite resin enhances proliferation and function of human macrophages. The effect may be associated with hypersensitivity of dentin. Glass-ionomer cement has little effect on proliferation of macrophages, but may lead to progress of inflammation.

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The prevalence of dehiscence and fenestration on anterior region of skeletal Class Ⅲ malocclusions：a cone-beam CT study

SUN Liang-yan, WANG Bo, FANG Bing

2013, 22 (4): 418-422.

Abstract ( 545 )

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PURPOSE: To investigate the prevalence and distribution of alveolar bone dehiscence and fenestration in anterior region of skeletal Class Ⅲ malocclusions. METHODS: The sample consisted of 19 males and 25 females with skeletal Class Ⅲ malocclusions selected from consecutive patients of Department of Oral and Cranio maxillofacial Science from May 1st to June 1st, 2012. Five hundred and twenty-three teeth were examined by cone-beam CT (CBCT) in total while alveolar bone dehiscences and fenestrations were detected and measured using a new method. The data was processed using SAS8.02 software package. RESULTS: The prevalence of dehiscence was 61.57% in all teeth, while fenestration was 31.93% and the prevalence of defect (dehiscence or fenestration) was 77.44%. More defects were found in the mandible (58.52%) especially. The tooth site which was most commonly affected was lower canine, while the least was upper central incisor. No significant difference was found between both genders on most tooth sites of anterior region but more defects was found in lower central incisor and lower lateral incisor in male subjects. CONCLUSIONS: Alveolar defect is an extremely common finding in this sample. Whether alveolar defects such as dehiscence and fenestration are potential factors of root resorption and addition bone loss is still unclear, and further researches are needed.

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A clinical study of osteotome sinus floor elevation and simultaneous implant placement in the periodontally compromised patients

ZHANG Yun-xin, LI Chao-lun, SHU Rong, XIE Yu-feng, LIU Xiao-feng, LIU Da-li

2013, 22 (4): 423-427.

Abstract ( 357 )

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PURPOSE: To study the clinical effect of osteotome sinus floor elevation (OSFE) combined with simultaneous implant placement in the treatment of edentulous posterior maxilla subject to insufficient bone height in the periodontally compromised patients. METHODS: Forty-seven Straumanns implants were placed in the posterior maxilla in 35 patients with the procedure of OSFE. The final prostheses were restored after 3 to 6 months. The follow-up period was 6 to 30 months. Radiographs were taken and PD, PLI, BOP were measured and analyzed. RESULTS: The overall survival rate was 95.74% during the study period. Forty-five out of the 47 implants were clinically stable and loaded without pain or any subjective sensation. The perforation ratio of the membrane was 4.26%. The average of PD around the implants was (3.22±1.07) mm. The average of the marginal bone loss was (1.38±0.59) mm. CONCLUSIONS: OSFE without bone graft proves to be an effective and predictable treatment for atrophic edentulous posterior maxillary region in patients with periodontitis, but the long-term effect needs further observation.

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Comparison of the IL-27 level in gingival crevicular fluid of cross-quadrant and the upper and lower half-mouth subgingival scaling

HAN Jia-jia, LIU Ming-peng, JIN Ying, LIU Di-xin, FANG Xu, LIN Xiao-ping

2013, 22 (4): 428-431.

Abstract ( 382 )

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PURPOSE: To investigate the changes of IL-27 in gingival crevicular fluid (GCF) before and after treatment with different methods for chronic periodontitis. METHODS: Sixty patients with moderate or severe chronic periodontitis were selected as study group to divide into group A (cross-quadrant) and group B (upper and lower half-mouth) randomly. Another 30 healthy people were selected as group C. Gingival crevicular fluid of group A and B were collected at baseline and each week during treatment. At the same time, the clinical parameters including PD, AL, BI and PLI were recorded. And the levels of IL-27 in GCF were measured by ELISA. SPSS 17.0 software package was used for statistical analysis. RESULTS: The levels of IL-27 in GCF 2 and 3 weeks after treatment were higher in study group compared with those at baseline, while PD, AL, BI and PLI showed significant reduction. The changes except PLI in group A was more obvious than group B, which had a significant difference. After three-week treatment, IL-27 in group A had no remarkable difference compared with group C. There were significantly negative correlation between PD, AL, BI, PLI and IL-27. CONCLUSIONS: IL-27 in GCF can be considered as a potential target for prevention and treatment of chronic periodontitis. Compared with the upper and lower half-mouth subgingival scaling, cross-quadrant has more pronounced short-term effect.

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The relationship between Streptococcus sobrinus and rampant caries in children

WANG Yun-xia, LIU Xue-jun

2013, 22 (4): 432-437.

Abstract ( 425 )

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PURPOSE: To explore the relations between Streptococcus sobrinus (S. Sobrinus) and rampant caries in children. METHODS: Based on previous investigation result for rampant caries in Zhengzhou city, 66 children aged 3-5 years were selected by random sampling, and divided into 3 groups of rampant caries, high dental caries and no caries, 22 cases in each group. The final identification of S. mutans and S. sobrinus were performed after using culture medium TYCSB to operate preliminary screening of Streptococcus mutans (S. Mutans) and S. Sobrinus with polymerase chain reaction(PCR) combined with physiological and biochemical identification. SPSS10.0 software package was used to compare the detection rate and mean values of S.mutans and S.sobrinus in the experimental group and the control group. RESULTS: It was found that single S. sobrinus without S. mutans was not detected from dental plaque in each group. The detection rate of S. mutans in group of rampant caries was higher than in group of high dental caries, but there was no significant difference (P>0.05). The difference of detection rate of S. sobrinus between the two groups and the detection rate of S. mutans between group of rampant caries and group without caries was significant(P<0.05). The difference of the detection rate of S. sobrinus between group of rampant caries and group without caries was also significant(P<0.01). The incidence of rampant caries, DMFT, DMFS, smooth-surface caries among the sample with both of S. sobrinus and S. mutans detected and the sample only with S. mutans and the sample without S. sobrinus and S. mutans were significantly different (P<0.01). CONCLUSIONS: The main pathogenic bacteria of rampant caries in children are S. mutans and S. sobrinus. The incidence of rampant caries was related to S. sobrinus, which had synergic effect on the occurrence and development of rampant caries in children.

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DNA repair gene polymorphisms in ERCC4 rs6498486 and ERCC5 rs751402 and risk of salivary gland tumors

MENG Xue, WANG Qiu-xu, CHEN Mo-ye, QIN Gang, WANG Yu-peng, LIU Wei-xian

2013, 22 (4): 438-442.

Abstract ( 281 )

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PURPOSE: To investigate the association between ERCC4 and ERCC5 polymorphisms and risk of salivary gland tumors. METHODS: Case-control study was carried out in 133 cases of histologically confirmed salivary gland tumors and 142 age and gender matched healthy control cases. Polymorphisms of ERCC4 rs6498486 and ERCC5 rs751402 were detected by PCR-RFLP. Multiple factors logistic regression analysis was conducted to investigate the association between gene polymorphisms and risk of salivary gland tumors using SPSS 18.0 software package. RESULTS: The genotype distribution of each polymorphism was found to be of Hardy-Weinberg equilibrium in the study. ERCC5 rs751402 TT genotype was associated with risk of salivary gland tumors (TT vs. CC+CT: OR=0.45, 95% CI: 0.21-0.98, P=0.046). No significant association was found in ERCC4 rs6498486. CONCLUSIONS: The results suggest that ERCC5 rs751402 polymorphism may be associated with risk of salivary gland tumors.

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Computer aided design and computer aided manufacture of template for crown lengthening

ZHAO Yan-bo, WU Lin, TANG Xiao-lin, GUO Chen

2013, 22 (4): 443-447.

Abstract ( 244 )

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PURPOSE: To introduce a method applied in computer aided design and computer aided manufacture (CAD-CAM) of template for crown lengthening. METHODS: Point cloud data of dental stone model of the patient in the plan of crown lengthening surgery was obtained by laser scanning. The following processes were carried out, constructing 3-D curve of the gingiva, drawing template outline on the triangle mesh model, shelling it for 3-D model of template, and transferring the data to rapid prototyping equipment for manufacture. RESULTS: 3-D model of the template was preliminarily accomplished. The resin template was manufactured with rapid prototyping equipment. The fitness between resin template and plaster model was good. CONCLUSIONS: This method, as an integrated procedure including data acquisition, 3-D computer modeling and fabrication by rapid prototyping, is feasible to implement CAD-CAM of template for crown lengthening.

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Evaluation of three-dimensional changes after sinus floor augmentation with DBBM

GUO Xue-hua, JIANG Qian, RUAN Hong, LUO Ying, YU You-cheng

2013, 22 (4): 448-452.

Abstract ( 319 )

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PURPOSE: The objective of present study was to assess the dimensional stability of the grafting material DBBM (Bio-oss )after maxillary sinus floor augmentation with spiral computed tomography (SCT) scans and 3D reconstruction. METHODS: Two postoperative SCT scans were available from 12 patients who had undergone maxillary sinus lift procedures. CT scan was taken at 2 week after surgical intervention and 6 months later, respectively. A total of 12 maxillary sinuses were augmented with 100% DBBM before implant insertion by lateral antrostomy in a staged approach. The augmentation volume was calculated using the SurgiCase CMF5.0 software. Data were calculated by Stata10 software package. RESULTS: The mean volume of the graft was reduced by 19.40%. Specifically, the reduction reached 0.29%in the buccal-palatal direction, 5.87% in the mesial-distal dimension, and 14.32% in vertical dimension. CONCLUSIONS: This study confirmed that the volume of DBBM has a certain amount of reduction within 6 months after sinus floor augmentation. The reduction in vertical direction is most severe.

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Application of joint reconstruction with autogenous coronoid process graft to treat temporomandibular joint ankylosis

XIE Qing-tiao, HUANG Xuan-ping, JIANG Xian-fang, YANG Yuan-yuan, LI Hua, LIN Xi

2013, 22 (4): 453-455.

Abstract ( 276 )

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PURPOSE: To evaluate the clinical effect of joint reconstruction by using autogenous coronoid process graft to treat temporomandibular joint(TMJ) ankylosis. METHODS: Nine cases of TMJ ankylosis from September 2008 to September 2010 were surgically treated by joint reconstruction with autogenous coronoid process graft, using autogenous articular disc or prosthodontic membrane as interpositional material. Mouth opening, occlusion and cone beam CT(CBCT) were used for evaluation before and after surgery. RESULTS: Satisfactory mouth opening was achieved in all patients and no one got occlusal changes or reankylosis during follow-up. CBCT showed that coronoid process graft reached bone union with the ramus and turned to be round. CONCLUSIONS: It is effective to cure TMJ ankylosis through joint reconstruction with autogenous coronoid process graft.

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Gingival retraction paste versus gingival retraction cord for fixed prosthodontics: a systematic review

HONG Le-guan, GUO Li-ping, XUE Li-li

2013, 22 (4): 456-461.

Abstract ( 420 )

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PURPOSE: To assess the efficacy of gingival retraction paste versus gingival retraction cord in fixed prosthodontics on gingiva protection, tooth preparation, clarity of the impression and plaster model, and aptness of the prosthesis. METHODS: Chinese BioMedical Literature Database, VIP, China National Knowledge Infrastructure (CNKI) and Wangfang database were searched on November 15th 2012 for eligible studies. Hand-searching included references of the included studies and Chinese dental journals. Risk of bias of the included studies was assessed by 2 reviewers independently using Cochrane Collaboration’s tool, and data extraction was done by the 2 reviewers. Meta analysis was performed with Revman 5.1 software. RESULTS: Nine randomized controlled trials, involving 1153 participants, were included. All of them had moderate risk of bias. Meta analysis revealed that gingival retraction paste had better effect on gingival health [RR=1.05, 95%CI (1.00, 1.11), P=0.04], tooth preparation [RR=1.17, 95%CI (1.07, 1.28), P=0.0008] and clarity of the impression and plaster model [RR=1.08, 95%CI (1.03, 1.13), P=0.0009] than gingival retraction cord, and the aptness of the prosthesis was as good as the cord [RR=1.07, 95%CI (0.96, 1.19), P=0.21]. CONCLUSIONS: The gingival retraction paste has better effect on gingival health, tooth preparation and clarity of the impression and plaster model, while the aptness of the prosthesis is as good as the cord and can be considered as a good candidate of the gingival retraction cord, but more randomized controlled trials are needed.

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Application of problem-based learning in pre-job training of postgraduate students in department of endodontics

SHAO Li-na, WANG Xue-mei, QIU Li-hong, ZHAN Fu- liang, XUE Ming

2013, 22 (4): 462-465.

Abstract ( 237 )

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PURPOSE: To apply problem-based learning (PBL) in pre-job training of postgraduate students in department of endodontics. METHODS: Thirty master degree postgraduate students of China Medical University were randomly divided into 2 groups, there were 15 students in each group. One group were taught with PBL method while the other group with lecture-based learning (LBL) method. The teaching effect was measured with examination and questionnaire survey. The data were analyzed by student's t-test using SPSS 11.5 software package. RESULTS: There was no significant difference in basic knowledge, medical records writing, oral examination between the two groups (P>0.05). There were significant differences in case analysis, dental operation, theory examination, practical examination and total scores between the two groups (P<0.05). The PBL method was welcomed by master degree postgraduate students. CONCLUSIONS: The abilities of postgraduate students can be developed by PBL method in different aspects. PBL achieves satisfactory teaching effect, and can be applied in pre-job training of postgraduate students.

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Application of autogenous artery to repair parotid duct defect

CHI Yu-feng, WANG Wei, TAN Xi-tao

2013, 22 (4): 466-468.

Abstract ( 230 )

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PURPOSE: To use autogenous artery to repair parotid duct defect, and to investigate the clinical effect. METHODS: Anesthesia epidural catheter was used to support the parotid duct and a segment of superficial temporal artery was harvested to reconstruct the defect of the parotid duct. The patients were asked to revisit 1 month, 3 months, half a year and one year postoperatively. RESULTS: No swelling and salivary fistula was noted. The parotid ducts were successfully reconstructed with good patency and normal secretion. CONCLUSIONS: Using anesthesia epidural catheter to support the parotid duct, autogenous artery is excellent for repair of parotid duct defect.

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IgG4-associated parotitis：case report and review of the literature

ZHANG Qing, FANG Li-hua, PING Jin-liang

2013, 22 (4): 473-477.

Abstract ( 331 )

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A case of immunoglobulin G4 (IgG4)-associated parotitis was reported and related literatures were reviewed,in order to improve the recognization of this systemic diseases and reduce the misdiagnosis and mistreatment in clinical practice for the stomatologists.

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Atypical solitary fibrous tumor of the buccal mucosa: report of 1 case

PEI Jing, CHEN Wei-hua, JIA Yun-xiang

2013, 22 (4): 478-480.

Abstract ( 220 )

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Solitary fibrous tumor is often considered to be a mesenchymal tumor. We reported a case of atypical SFT of the buccal mucosa in a 56-year-old male patient. We found hypercellularity, nuclear atypia, increased number of mitotic figures(more than 4 per 10 high-power fields) microscopically. A long-term follow-up is necessary after complete excision.

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