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15 September 2012, Volume 5 Issue 9 Previous Issue    Next Issue

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Tooth replantation of avulsed teeth WANG Jun. 2012, 5(9): 513-517.  Abstract ( )   The prognosis of replanted teeth depends on several factors， post-traumatic external root resorption eventually resulting in loss of the traumatized tooth is a frequent finding. How to improve the healing of the replanted teeth is always a big challenge for pediatric dentists. Simply， replantation procedures involve preparation of the root surface， preparation of the socket， replantation and splinting. Moreover， adjunctive therapy， such as systemic antibiotics， Tetanus and patient instructions should be dealt with. Choice of treatment is related to the maturity of the root (open or closed apex) and the condition of the periodontal ligament cells. In this paper， the treatment of root surface， the type and time of splinting for replanted teeth and the endodontic treatment will be discussed briefly.

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Assessment of pulp sequela of young permanent teeth after traumatic dental injuries  QIN Man. 2012, 5(9): 517-520.  Abstract ( )   Dental trauma could be largely classified into three groups： hard tissue injuries， pulp injuries and periodontal tissue injuries. Since pulp injuries are reported in tooth fracture， displacement and avulsion， it is commonly thought that pulp injuries were invovled in almost every type of dental injuries. The sequelae of pulp tissue after dental injuries includes pulp survival， pulp calcification and pulp necrosis. The following factors are considered generally in evaluating the sequelae of pulp tissue after dental injuries， such as 1) the pulp injury due to the dental trauma， 2) the secondary pulp injury due to harmful environmental factors， 3) root development and individual differences， et al. The treatment and prognosis of dental trauma in children are more complicated than those in adults because of the developmental nature of the young permanent teeth. The evaluation of pulp damage and treatment after dental injuries in growing young permanent teeth is discussed in this paper.

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Analysis of root canal morphology ZHAN Fu-liang，LI Li. 2012, 5(9): 521-526.  Abstract ( )   Successful endodontic treatment involves accurate diagnosis，sufficient root canal preparation and proper obturation，which are based on a thorough knowledge of root canal morphology. The wrong diagnosis and treatment of aberrant root canal and the incidence of a missed canal are the most important factors in endodontic treatment failure. This article is a review of the root canal morphology，methods of determining the actual number of root canals present，aberrant root canal morphology and the development of methods of root canal morphology research.

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Effect of local hIL-10 gene transfer on experimental periodontitis in ovariectomized rats  CHEN Qun*，MA Shou-zhi， GUO　Jian-bin，JIANG　Jun，ZHAO　Xin，YAN Fu-hua， XIAO　Yin. 2012, 5(9): 527-532.  Abstract ( )   Objective    To investigate the effect of local hIL-10 gene transfer on bone metabolism， absorption of alveolar bone， and expressions of cytokines in periodontal tissue in ovariectomized rats. Methods    Twenty-four SD female rats were randomly divided into four groups. Group A： SHAM+hIL-10； Group B： SHAM+VECTOR； Group C： OVX+hIL-10； Group D： OVX+VECTOR. Twelve weeks after SHAM or OVX operation， the experimental periodontitis were induced by placing 4-0 silk ligatures around the cervix of the left upper second molars. At the same time， the complex of 5μg hIL-10 plasmid with 5μL liposome for Group A and C or 5μg vector plasmid with 5μL liposome for Group B and D were injected into the palatal gingiva of the upper second molars on left sides one time every two days. However， the palatal gingiva of the upper second molars on the right sides were also injected with the same complex as the left for Group A and Group B. Twenty hours after the seventh injection， the rats were sacrificed and bone density， serum biomechanical marker， absorption of alveolar bone and the numbers of cytokine-positive cells in the furcation were measured to detect the effects of hIL-10 gene therapy on bone metabolism， absorption of alveolar bone and the expression of cytokines in the periodontal tissue. Results    It was demonstrated that significantly increased hIL-10 expression was detected in the periodontal tissues after local gene delivery. It was also noted that after hIL-10 gene local delivery， the expression levels of  IL-1β， IL-6， TNF-α， RANKL and MMP-8 were significantly downregulated in the furcation of ligatured teeth and the alveolar bone absorption was significantly decreased （P < 0.05）. Conclusion    The hIL-10 gene transferred by local injection has significant effect on the absorption of alveolar bone and the expression of cytokines including IL-1β， IL-6， TNF-α， RANKL and MMP-8 in periodontal tissues of experimental periodontitis in ovariectomized rats.

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Study on influence of active coating containing zinc of pure titanium surface on the activity of osteoblasts LIU Yang*， ZHANG Wei， ZHAO Bao-hong， LIN Zeng， WANG Dan-ning， FENG Wei， ZHONG Ming. 2012, 5(9): 533-538.  Abstract ( )   Objective    Active coating containing Zinc was deposited onto pure titanium using micro-arc oxidation （MAO） technology to evaluate the influence of activity of MG63. Methods    Our experiment was performed at Center Laboratory of China Medical University Affiliated Stomatology Hospital from October 2009 to October 2010. Pure titanium of mechanical polishing was used as control （CP group）， and according to the Ca volume， the titanium substrates treated by MAO were distributed to high calcium surface （H-Ca group）， low calcium surface （L-Ca group）， and low calcium and zinc surface （L-Ca-Zn group）. There were 32 specimens in each group. Cultivate osteoblasts （MG63） on different surfaces， and SEM， MTT assay， ALP activity， and ELISA was used to evaluate the influence of different substrates on attachment， proliferation， differentiation and mineralization of the cells. Data were analyzed by one-way ANOVA （α=0.05） performed with SPSS13.0. Results    The performance of H-Ca group on attachment， proliferation， differentiation and mineralization of the cells was better than L-Ca group （P < 0.05）. At the initial phase of experiment， there was no significant difference between L-Ca-Zn and L-Ca （P > 0.05）. At the later phase of experiment， the surface cells on L-Ca-Zn group showed better activity than on L-Ca group， and there was no significant difference between L-Ca-Zn and H-Ca in the results of MTT and ALP activity experiments （P > 0.05）. Conclusion    Active coating containing Zinc deposited onto pure titanium by MAO method promotes the attachment， proliferation and differentiation of MG63， and shows good biocompatibility.

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Awareness of basic oral health knowledge and routine oral health behavior of 8362 visitors in dental clinic of China-Japan Friendship Hospital  HE Tian-peng， LI Xin， SUN Qiang. 2012, 5(9): 538-541.  Abstract ( )   Objective    To survey the information of diagnosis， awareness of basic oral health knowledge and routine oral health behavior of visitors in dental clinic of China-Japan Friendship Hospital， Beijing. Methods    According to the questionnaire of national oral epidemiological survey， the questionnaire including the general demographic information， oral health knowledge awareness and oral health behaviors was designed. Visitors to this dental clinic in 2011， whose age was or was older than 7 years， were surveyed. Database was established by Epidata3.0 and statistical analysis was performed by SPSS15.0. Results    The two main oral diseases were periodontal disease and caries，with the proportion being 36.0% and 28.7% in 8362 cases respectively in 2011. The awareness of the correct method of brushing， dental calculus， dental plaque， reasonable tooth brushing frequency accounted for 30.2%， 22.1%， 10.9% and 2.4%，respectively. The percentage of taking the correct method of brushing and having ever washed teeth was 15.1% and 10.2%. The percentage of often eating sweets before sleeping was 20.4%. The percentage of having not received oral health education was 37.8% and 65.2% had never seen dental doctors in recent five years. The percentage of regular smokers， regular drinkers， regular late sleeping and non-often physical exercise accounted for 39.2%， 36.5%， 40.6% and 76.4%，respectively. The main ways to receive oral health knowledge were newspapers， television， and network. Conclusion    The awareness of oral health knowledge and the percentage of adoping healthy behaviors are both low in visitors to this clinic. Health education should be further strengthened among them.

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Study on the effect of silver amalgam filling and removing on patients' renal function CHEN Ling， WU Yun， WANG Yi-yong， WEI Bin. 2012, 5(9): 542-544.  Abstract ( )   Objective    To explore the effect of silver amalgam filling and removing on　patients' renal function. Methods    The patients were selected in the dental clinic of First Clinical Medical College of Fujian Medical University from March 2010 to October 2010.Oral health checks were carried out；24 patients with caries receiving no filling were selected as group A. At the same time， 25 patients with histories of amalgam restoration longer than 2 years and needing to replace by composite resin restorations were selected as group B. Respectively fill and remove silver amalgam in two groups. Respectively after 1 day， 1 week， 2 weeks， 4 weeks and 8 weeks，collect patients urine， determining the β2-MG，NAG and mALB concentrations in urine and compare. Results    After 1 day in the filling and removing groups NAG andβ2-MG concentrations in urine increased significantly . After 1 week， 2 weeks， 4 weeks and 8 weeks in the filling and removing groups NAG and β2-MG concentrations in urine had non-significant difference from before. Urine mALB in filling and removing groups had non-significant difference between every time point. Conclusion    The mercury release in silver amalgam use won't impact renal function.

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Clinical trial on correction of skeletal open bite with rapid molar intruder TANG Kai-hong， WANG Zeng-quan. 2012, 5(9): 545-547.  Abstract ( )   Objective    To study the effect of rapid molar intruder （RMI） on skeletal open bite. Methods    Seven skeletal open bite patients were orthodontically treated with RMI. The first molars were attached to transpalatal arch and mandibular lingual arch. No other intrude force was applied.  Results    All the patients felt uncomfortable in the first week and then adapted to that. The over-bites attained 1～2.3 mm after 3 to 7 months. Conclusion    The RMI appliance can correct skeletal open bite effectively.

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Influence of Er，Cr∶YSGG laser on the microtensile bond strength of a resin cement to dentin AN Xin， JIA Xing-ya， YANG Chao， WANG Shu-zhi. 2012, 5(9): 548-551.  Abstract ( )   Objective    To evaluate the influence of dentin age and Er，Cr∶YSGG laser on the microtensile bond strength of a rensin cement to dentin. Methods    Twenty extracted molars from subjects over 65 years old（Group A） and 20～44 years old（Group B） were selected and randomly divided into subgroups（Group A1，A2，B1，B2）. Then teeth in Group A1 and B1 were processed with Er，Cr∶YSGG laser while teeth in Group A2 and B2 were processed with high-speed dental turbine handpiece，combined with self-etching adhesive and filled with composite resin （Z350）. All subjuects were saved in distilled water for 24 hours at 37℃ .Then they were cut into hourglass-shaped specimens and the microtensile bond strength was evaluated. All specimens were examined under stero-microscope. Results    There was significant difference between aged dentin group and young dentin group （P < 0.05） but no difference between  Er，Cr∶YSGG laser group and turbine handpiece group （P > 0.05）.There was no significant difference of breakage modes among four groups（P > 0.05）.Conclusion    This in vitro study showed that aging of dentin negatively affects the microtensile bond strength，while  Er，Cr∶YSGG laser irradiation does not negatively affect the bond strength of aged and young dentin.

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Effect of cleanness at the root tip by using five different techniques in root canal preparation LIU Yan， MA Wei-dong，GAO Wei-Hong 2012, 5(9): 551-554.  Abstract ( )   Objective    To compare the ability of five techniques on cleanness at the apical third of root. Methods    Sixty extracted single-rooted human teech ，randomly distributed into 6 groups ，were prepared by using Protaper rotary instruments and subjected to different techniques on removal of smear layer；hydrogen peroxide and normal saline（ group A）； 5.25%sodium hypochlorite（NAOCL） and ethylenediamine tetraacetis（EDTA） gel （group B），irrigation with ultrasonics（group C）； with Nd：YAG laser（ group D）， EDTA gel and ultrasonics with normal saline irrigation （group E）；EDTA gel and ultrasonics with 5.25% NAOCL irrigation （ group F）. Samples were examined under the scanning electron microscope （SEM） and scored for cleanness at the apical third of root and the condition of dentin tubule. Results    In group A the apical root and dentine tubules were covered by smear layer. The smear layer of the other 5 groups were cleared partly.There were significant difference bwteen group A and other groups（P < 0.05）. There were no significant difference between the group D and group E（P > 0.05）. There were significant difference among  the other tested groups（P < 0.05）. Conclusion    the smear layer at the root tip can be removed effectively  by using chemical ，ultrasonics and Nd：YAG laser. EDTA gel combined with ultrasonics and 5.25% NAOCL irrigation （group F） was best.

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Clinical analysis of maxillofacial osteosarcoma after radiotherapy in 27 cases YOU Yun-hua， LIN Yong-feng，LIANG Jun， GOU Xin-min 2012, 5(9): 555-557.  Abstract ( )   Objective    To investigate the clinical and pathological features ，treatment and prognosis of osteosarcoma after maxillofacial radiology. Methods    Retrospective analyze 27 cases of maxillofacial patients with osteosarcoma after radiotherapy from January 2003 to January 2012， in the Fifth Affiliated Hospital of Sun Yat-sen University， describe the time of occurrence， clinical and pathological features and treatment，and follow up the prognosis. Results    Of the 27 patients， 2 patients，because of tumor invasion of the extensive and multiple bone metastases，were inoperable and treated by palliative chemotherapy， but the results were poor，and one year later，they died of lung metastasis and multiple bone metastases. One patient was with lesions involving great range；after comprehensive treatment such as surgery， chemotherapy and radiotherapy， six months later， tumor recurred，and after 1 year he was discovered with lung metastases； several times of chemotherapy proved to be ineffective，and he died in one and a haif  year after operation. The remained 24 cases is relatively limited in the extent of disease， and they received extended surgery resection and chemotherapy；10 cases died in 1 to 2 years after diagnosis，and 12 patients were followed up for 9 months to 5 years without evidence of recurrence，while 2 cases were lost. Conclusion    Osteosarcoma after maxillofacial radiology is of high degree of malignancy， and the prognosis is poor；surgery combined with preoperative and postoperative chemotherapy may improve prognosis.

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Study progress on the mechanism of regenerative endodontic treatment  ZHANG Dan-dan，BAO Zhi-fan， CHEN Xu. 2012, 5(9): 560-563.  Abstract ( )   An important step of regenerative endodontic treatment is to pierce the tooth apical tissue and make the blood flow into the root canal. This procedure will make the stem cells flow into the root canal，thus blood bolt can provide matrix and scaffold for stem cells aggregation；moreover，the flowing blood contains rich growth factors， which can induce stem cells’ proliferation and differentiation. They play a key role in promoting continual deposition of hard tissue in the root canal and the root development of immature permanent tooth. In this article， researches on regenerative endodontic treatment in recent years are reviewed.

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Early diagnosis and prevention of orthodontic root resorption Zulihuma·Arefujiang， PAN Xu， MI Cong-bo. 2012, 5(9): 564-569.  Abstract ( )   Root resorption is one of the common syndromes during the orthodontic treatment. Although severe root resorption is rarely seen， as an unpredicable syndrome， it has disturbed orthodontist for dacades. This review summarized the early diagnosis and prevention of orthodontic root resorption.

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Study on the relationship between lysozyme and common oral diseases GAO Jing，ZHANG Ling. 2012, 5(9): 570-574.  Abstract ( )   Lysozyme is a kind of cationic protein and widely present in tissues，circulating cells， serum，tears，saliva，other exocrine secretions of human body. Lysozyme，a component of the host non-specific immune system found in saliva，has significant antifungal activity and anti-inflammatory effect. This review describes the relationship between common oral diseases and the level of lysozyme.