Smad7在成牙本质细胞系MDPC-23内转化生长因子β信号转导中的作用

目的研究Smad7在成牙本质细胞系MDPC-23内转化生长因子(transforming growth factor-β1, TGF-β)信号转导的作用.方法培养MDPC-23细胞,免疫组化法观察TGF-β1对MDPC-23细胞内Smad7分子定位改变.通过瞬时共转染和报告基因检测方法观察Smad7分子对TGF-β1调控目的基因转录的影响.结果MDPC-23细胞表达Smad7蛋白,主要定位于细胞胞浆,在转化生长因子β1刺激30 min后,Smad7从胞核向胞浆转位聚集.TGF-β1显著诱导p3TP-Lux基础启动子活性.过表达Smad7完全抑制TGF-β1对p3TP-Lux启动子活性的诱导,而过表达Smad7反义cDNA载体则显著促进了TGF-β1对p3TP-Lux启动子活性的诱导.结论在成牙本质细胞系MDPC-23内,Smad7可能作为一种抑制性Smad分子在拮抗TGF-β1信号转导过程中发挥重要的作用.     

Smads蛋白在成牙本质细胞系MDPC-23中的表达及功能

目的研究Smads蛋白在成牙本质细胞系MDPC-23作为转化生长因子(TGF)β信号分子的作用。方法常规条件下培养MDPC-23细胞,在TGF-β1刺激培养1h后,观察细胞内Smad分子的定位变化。将Smads真核表达载体分别与报告基因载体p3TP-Lux瞬时共转染至MDPC-23,在TGF-β1刺激培养24h后,裂解细胞,用双荧光素酶报告基因检测系统检测细胞裂解液中的荧光素酶活性。结果MDPC-23细胞表达Smad2和Smad3蛋白分子,主要定位于细胞质,在TGF-β1刺激1h后,Smad2和Smad3从胞质向胞核转位聚集。TGF-β1可诱导p3TP-Lux基础启动子活性,约增加13倍。过表达野生型Smad3蛋白可促进TGF-β1对p3TP-Lux启动子活性的诱导,但是过表达Smad3突变体抑制TGF-β1对p3TP-Lux启动子活性的诱导。和Smad3作用相比,过表达Smad2野生型或突变型蛋白对TGF-β1诱导p3TP-Lux启动子活性无明显影响。结论在成牙本质细胞系MDPC-23内,Smad信号途径存在并参与介导TGF-β1诱导的转录调控。     

MDPC-23细胞内Smad信号途径在转化生长因子β1调控Smad7基因转录中的作用

目的：研究成牙本质细胞系MDPC-23内Smad信号途径在转化生长因子β1(transforming growth factor-β1，TGF-β1)调控Smad7基因转录调控中的作用，从基因转录水平探讨成牙本质细胞内TGF-β调控Smad7基因表达的分子机制。方法：培养MDPC-23细胞，通过瞬时共转染和报告基因检测方法观察Smad蛋白分子对Smad7启动子活性的影响，实验数据采用单因素方差分析。结果：当Smad7启动子(-408bp至 112bp)荧光素酶活性载体表达在MDPC-23细胞时，其基础启动子活性被TGF-β1显著诱导增加，而骨形成蛋白2(bone morphogenetic protein-2，BMP-2)对其活性无明显影响。单独过表达Smad1、2、4、5对Smad7启动子活性无明显影响。Smad3过表达显著增强Smad7启动子活性，而Smad3与Smad4共转染进一步增强了Smad3的作用。过表达Smad3突变型载体或Smad3反义cDNA(AS-Smad3)均显著抑制TGF-β1对Smad7启动子活性的诱导作用。结论：在成牙本质细胞系MDPC-23内，TGF-β通过Smad3与Smad4协同调控Smad7基因转录。     

MDPG-23细胞内Smad信号途径在转化生长因子β1调控Smad7基因转录中的作用

目的研究成牙本质细胞系MDPC-23内Smad信号途径在转化生长因子β1(transforming growth factor-β1,TGF-β1)调控Smad7基因转录调控中的作用,从基因转录水平探讨成牙本质细胞内TGF-β调控Smad7基因表达的分子机制.方法培养MDPC-23细胞,通过瞬时共转染和报告基因检测方法观察Smad蛋白分子对Smad7启动子活性的影响,实验数据采用单因素方差分析.结果当Smad7启动子(-408 bp至+112bp)荧光素酶活性载体表达在MDPC-23细胞时,其基础启动子活性被TGF-β1显著诱导增加,而骨形成蛋白2(bone morphogenetic protein-2,BMP-2)对其活性无明显影响.单独过表达Smad1、2、4、5对Smad7启动子活性无明显影响.Smad3过表达显著增强Smad7启动子活性,而Smad3与Smad4共转染进一步增强了Smad3的作用.过表达Smad3突变型载体或Smad3反义cDNA(AS-Smad3)均显著抑制TGF-β1对Smad7启动子活性的诱导作用.结论在成牙本质细胞系MDPC-23内,TGF-β通过Smad3与Smad4协同调控Smad7基因转录.     

人牙乳头细胞内Smad2在TGF-β1信号转导中作用的研究

目的观察体外原代培养的人牙乳头细胞内Smad2蛋白的表达,以及Smad2蛋白在转化生长因子-β1信号转导中的作用,探讨Smad2信号途径在TGF-β1调控牙乳头细胞向成牙本质细胞分化过程中的作用机制.方法原代培养人牙乳头细胞,Westernblot杂交方法检测内源性Smad2的表达和TGF-β1调控下的表达变化,用免疫组化方法观察Smad2细胞内定位变化.结果培养的人牙乳头细胞表达Smad2蛋白,TGF-β1能引起Smad2从胞浆转位至核内聚集,而BMP-2无此功能;TGF-β1或BMP-2刺激作用6h、12h、24h和48h,牙乳头细胞内Smad2蛋白表达水平未见明显的改变.结论人牙乳头细胞内存在Smad2基因的表达,Smad2能被TGF-β1活化后转位至核内发挥作用,但Smad2基因的表达无明显变化,提示TGF-β1在调控牙乳头细胞向成牙本质细胞分化的过程中,Smad2信号途径可能发挥一定的作用.     

TGF-β1对成牙本质细胞系MDPC-23中 Smads mRNA表达的影响

目的：研究TGF—β1对成牙本质细胞系MDPC-23细胞中Smads mRNA表达的影响，探讨成牙本质细胞内Smads分子基因表达调控机制。方法：培养MDPC-23细胞，细胞分为5组，分别用TGF—β1刺激0、0．5h、1．5h、4h、24h，提取总RNA。用半定量RT—PCR观察Smad2、Smad3和Smad7mRNA表达变化。结果：MDPC-23细胞表达Smad2、Smad3和Smad7 mRNA。在TGF—β1作用24h内，MDPC-23细胞内Smad2 mRNA表达水平无明显变化。在TGF—β1作用4h后，Smad3 mRNA表达水平下调。Smad7 mRNA水平在TGF—β1作用下1．5h达到最高峰，以后逐渐下降。结论：在成牙本质细胞内，TGF—β1可能通过不同的方式调控其细胞内信号分子Smad2、Smad3和Smad7的表达，从而使成牙本质细胞对Smad介导的TGF—β1信号得到精确调控。     

人牙乳头细胞内Smad2在TGF—β1信号转导中的作用的研究

目的 观察体外原代培养的人牙乳头细胞内Sad2蛋白的表达,以及Smad2蛋白在转化生长因子-β1信号转导中的作用,探讨Smad2信号途径在TGF-β1调控牙乳头细胞向成牙本质细胞分化过程中的作用机制。方法 原代培养人牙乳头细胞,Western blot杂交方法检测内源性Smad2的表达和TGF-β1调控下的表达变化,用免疫组化方法观察Smad2细胞内定位变化。结果培养的人牙乳头细胞表达Ｓmad2蛋白,ＴＧＦ－β１能引起Ｓmad2从蛋白表达水平未见明显的改变。结论 人牙乳头细胞内存在Ｓmad2基因的表达,Ｓmad2能被ＴＧＦ－β１能引起Smad2从胞浆转位至核内聚集,而BMP-2无此功能;TGF-β或BMP-2刺激作用6h、12h24h和48h,牙乳头细胞内Smad2蛋白表达水平未见明显的改变。结论 人牙乳头细胞内存在Smad2基因的表达,Smad2能被TGF-β1活化后转位至核内发挥作用,但Smad2基因的表达无明显变化,提示TGF-β1在调控牙乳头细胞向成牙本质细胞分化的过程中,Smad2信号途径可能发挥一定的作用。     

TGF-β1/Smad3信号途径对牙本质涎磷蛋白基因表达的调控

目的：研究小鼠成牙本质细胞系MDPC-23中TGF-β1及其信号分子Smad3对小鼠牙本质涎磷蛋白（dentinsialophosphoprotein，DSPP）基因表达中的调控作用。方法：PCR法制备DSPP引物、构建带有DSPP启动子片段的萤火虫荧光素酶基因报告载体，通过瞬时转染入MDPC-23细胞后，检测报告基因活性。结果：在TGF-β1的作用下，Smad3可以发生转位表达，由细胞浆转入细胞核内。同时，过表达野生型Smad3可以显著增强TGF-β1对DSPP启动子活性的下调作用。结论：TGF-β1可以通过Smad3信号通路对DSPP启动子进行调控；在DSPP启动子-2525-＋54bp之间，存在TGF-β1／Smad3信号途径的结合位点，从而发挥对DSPP基因的调控作用。     

转化生长因子β1和重组人骨形成蛋白2对成牙本质细胞系MDPC-23牙本质基质蛋白1表达的影响

目的 观察转化生长因子β1(transforming growth factor β1,TGF-β1)和重组人骨形成蛋白2(bone morphogenic protein 2,rhBMP2)单独或联合作用对小鼠成牙本质细胞系 MDPC-23牙本质基质蛋白 1(dental matrix potein,DMP1)合成分泌的影响。方法 利用不同浓度的TGF-β1和rhBMP2以及二者联合刺激培养MDPC-23细胞,用免疫组化SABC方法和图像分析观察分析结果。结果 2μg/L的 TGF-β1能够增强 MDPC-23细胞 DMP1的表达;不同浓度的 rhBMP2均可增强细胞 DMP1的表达量,呈浓度依赖性增强;2μg/L的 TGF-β1和不同浓度的 rhBMP2联合应用可明显增强 DMP1的表达。诱导的 DMP1主要表达于胞质和细胞突起中。结论 TGF-β1和rhBMP2单独和联合应用能够增强成牙本质细胞系MDW-23产生DMP1,二者联合应用作用更加显著,说明二者对成牙本质细胞的分泌和成熟有一定促进作用。     

人牙髓细胞内Smad 2、3在转化生长因子β1信号转导中的作用

目的：探讨人牙髓细胞内Smad 2、3在转化生长因子β1（transforming growth factor-β1,TGF-β1)信号转导过程中的作用。方法：原代培养人牙髓细胞，用激光共聚焦显微镜观察TGF－β1刺激初期牙髓细胞内Smad 2、3由胞质向胞核转位的现象，同时采用Western blot方法检测刺激后期Smad 2、3蛋白表达的变化。结果：TGF－β1刺激2h内，Smad2、3在胞质中表达渐弱，在胞核内表达渐强，呈现由胞质向胞核逐步转位的趋势。Smad 2蛋白总量在TGF－β1刺激前后几乎无变化，而Smad 3在刺激后24h表达量明显下降，48h后表达十分微弱。结论：Smad 2、3可能是人牙髓细胞内TGF－β1的信号转导分子。TGF－β1刺激初期Smad 2、3通过发生转位参与转导TGF－β1信号至核内，刺激后期Smad 3表达水平的下调可能与TGF－β1负反馈调节自身的信号有关。     

Variation in periodontal referral in 2 regions in theUK

This study investigated the periodontal referral patterns of general dental practitioners (GDPs) in Northern Ireland (NI) and North West England (NWE). A questionnaire dealing with periodontal referral was sent to all 520 GDPs registered in NI and to 274 GDPs in NWE. A usable return was made by 355 (68%) in NI and 189 (70%) in NWE. The NI dentists made significantly more periodontal referrals (median 5, range 0-80) in the year preceding the survey than those in NWE (median 2, range 0-50), p<0.001. Distance was the only factor significantly related to the referral rate in both regions with those who practised more than 25 miles from a specialist referring significantly fewer patients in both regions. In NI, there was a trend towards increased periodontal referral by GDPs who had attended more postgraduate courses; however, in NWE, this was not the case. The GDPs in NWE were significantly less likely than those in NI to refer patients with medical conditions. It is concluded that there is considerable variation in periodontal referral both within and between the 2 regions studied. It is further concluded that in many cases, non-disease factors, such as the accessibility of the specialist service, have powerful effects on the decisions made by dentists and patients in these regions (NI and NWE) in relation to periodontal referral. Much of the variance in referral in North West England, as in Northern Ireland, remains unexplained.     

Trends in socioeconomic disparities in oral health in Brazil and Sweden

Celeste RK, Nadanovsky P, Fritzell J. Trends in socioeconomic disparities in oral health in Brazil and Sweden. Community Dent Oral Epidemiol 2011; 39: 204–212. © 2010 John Wiley & Sons A/S Abstract – Objectives: To describe the dynamics of trends in socioeconomic disparities in oral health in Brazil and Sweden among adults, to assess whether trends follow expected patterns according to the inverse equity hypothesis. Methods: In Sweden, we obtained nationally representative data for the years 1968, 1974, 1981, 1991 and 2000, and in Brazil, for 16 state capitals in 1986 and in 2002. Trends in the prevalence of ‘edentulism’ and of ‘teeth in good conditions’ were described in two groups aged 35–44 with lower and higher economic standards, respectively. Results: There was an annual decline in disparities in ‘edentulism’ of 0.4 percentage points (pp) (95% CI = 0.2–0.7) in Brazil and 0.7pp (95% CI = 0.5–0.9) in Sweden, as a result of improvements in both income groups. Concerning ‘teeth in good conditions’, in Brazil, there was improvement only in the higher income group and absolute disparities have increased (0.5pp annually), while in Sweden, there was a nonsignificant decrease (0.3pp annually) with improvements in both groups. Since 1991 in Sweden and in 2002 in Brazil, our measures of socioeconomic disparities in ‘edentulism’ were not statistically significant. Trends did not differ by sex or dental visit. Conclusions: Despite improvements in both income groups and a decrease in disparities in ‘edentulism’, the poorer group in Brazil has seen no improvement in ‘teeth in good conditions’ and disparities have increased. It appears that Brazil and Sweden reflect different stages of trend for ‘teeth in good conditions’ and the same stages for ‘edentulism’, represented by the inverse equity hypothesis.     

Fluorosis in relation to fluoride levels in water in central Nigeria

Abstract– Objectives : This study was conducted to examine the prevalence of dental fluorosis in relation to fluoride levels in water among children aged 12–15 years in the states of Plateau and Bauchi, Nigeria. Methods : Children ( N =203) were examined using WHO criteria. The children were from two schools and permanent residents of the communities in which the schools are located (Tilden Fulani and Kanadap). Intra-examiner reliability for determining fluorosis scores was 80%. Results : Fluoride levels in the water ranged from 0.0–0.4 mg/L. Prevalence of dental fluorosis in the sample was 51%. Forty-one percent had very mild fluorosis, 7% had mild fluorosis and 3% had moderate to severe fluorosis. The lowest DMFT was observed in the school where the fluoride level of the water ranged between 0.0 and 0.4 mg/L, and in the group with very mild fluorosis. Conclusion : Fluoride levels in water for central Nigeria were appropriate for oral health. In the areas where the children were permanent residents, factors other than the fluoride levels of the water contributed to the severity of dental fluorosis.     

Trends in endodontic claims in Italy

According to the scant data available in the literature, endodontic claims are common among dental professional liability cases and the second most common type of claim. This study aimed to describe the characteristics of endodontic claims in Italy and the most frequently disputed errors, and the discussion below includes consideration of ethical and medico‐legal aspects thereof. We retrospectively analysed 120 technical reports written on cases of professional malpractice in endodontics in the last 5 years. The complainant patients were males in 22.5% of the cases, while females made up the remaining 77.5%. In the dentist sample, male operators were more often involved in litigation cases (80%) than female operators. The most frequently claimed technical errors were: lack of a complete filling of root canal/s (71.7%), the perforation of tooth structure (12.7%), extrusion of sealing materials beyond the apex of the tooth (9.6%) and the fracture of an endodontic instrument (5.9%). In 1.7% of cases it was found that the expert did not make any errors performing the endodontic therapy. In only very few cases (2.7%) no therapy was considered necessary, while the most common therapeutic solution involved in endodontic misconduct was tooth extraction (53.0%). In many cases the dentist preferred to extract the endodontically undertreated tooth and substitute it prosthetically rather than trying to re‐treat it. The discrepancy between the total number of cases examined and those that eventually go to court leads us to believe that the majority of endodontic malpractice cases are resolved in out‐of‐court settlements.     

Human Herpesviridae in acute necrotizing ulcerative gingivitis in children in Nigeria

Herpesviruses have been implicated in the pathogenesis of human periodontitis. The present study investigated whether herpeasviruses are present in the lesions of acute necrotizing ulcerative gingivitis. Sixty-two Nigerian children, aged 3–14 years, were studied. Twenty-two children had acute necrotizing ulcerative gingivitis and were also malnourished, 20 exhibited no acute necrotizing ulcerative gingivitis but were malnourished, and 20 were free of acute necrotizing ulcerative gingivitis and in a good nutritional state. Polymerase chain reaction methods were used to determine the presence of human cytomegalovirus (HCMV), Epstein-Barr virus type 1 and type 2 (EBV-1, EBV-2), herpes simplex virus (HSV), human herpes virus 6 (HHV-6), human papilloma virus and human immunodeficiency virus type 1 in crevicular fluid specimens collected by paper points. Of the 22 acute necrotizing ulcerative gingivitis patients, 15 (68%) revealed viral infection and 8 (36%) viral coinfection. Thirteen (59%) acute necrotizing ulcerative gingivitis patients demonstrated HCMV, 6 (27%) EBV-1, 5 (23%) HSV and 1 (5%) HHV-6. Only 2 (10%) subjects from each group not affected by acute necrotizing ulcerative gingivitis showed viral presence, and no control subject revealed viral coinfection. These findings suggest that HCMV and possibly other herpesviruses contribute to the onset and/or progression of acute necrotizing ulcerative gingivitis in malnourished Nigerian children.     

Changes in caries prevalence in Japan

In Japan, the mean DMFT at 12 years of age increased from 2.8 in 1957 to 5.9 in 1975. From the 1981 survey (DMFT=5.43), conversely, the mean DMFT decreased and reached 3.64 in 1993. The increase in caries prevalence can, without doubt, be explained by an increment of sugar consumption, since the intake of sugar increased after World War II and exceeded 18.25 kg/year (50 g/day) in 1965 and reached a maximum value (29.3 kg/year) in 1973 in Japan. On the other hand, the reason why the DMFT has decreased since 1981 is not clear. In many industrialized countries, a caries reduction has been achieved with acceptable fluoride exposure, although sugar consumption was still at a high level. However, fluoride usage was still limited during the last 2 decades in Japan. There is no community where fluoridated drinking water has been supplied since 1972. Fluoride tablet use was also discontinued for children in the 1970s. Fluoride mouthrinsing programs were available for only 19r of school children in 1992. Moreover, the market share of fluoridated dentifrices stayed at 10% until 1986 and became 30% only in 1988. An excellent correlation (r=0.91; P 0.01) is observed between the DMFT in 12-year-olds and per capita sugar consumption per year between 1957 and 1987 in Japan.     

Advances in local anesthesia in dentistry

Local pain management is the most critical aspect of patient care in dentistry. The improvements in agents and techniques for local anesthesia are probably the most significant advances that have occurred in dental science. This article provides an update on the most recently introduced local anesthetic agents along with new technologies used to deliver local anesthetics. Safety devices are also discussed, along with an innovative method for reducing the annoying numbness of the lip and tongue following local anesthesia.     

Localization of SOST/sclerostin in cementocytes in vivo and in mineralizing periodontal ligament cells in vitro

Jäger A, Götz W, Lossdörfer S, Rath‐Deschner B. Localization of SOST/sclerostin in cementocytes in vivo and in mineralizing periodontal ligament cells in vitro. J Periodont Res 2009; doi: 10.1111/j.1600‐0765.2009.01227.x. © 2009 John Wiley & Sons A/S Background and Objective: Cementum and bone are rather similar hard tissues, and osteocytes and cementocytes, together with their canalicular network, share many morphological and cell biological characteristics. However, there is no clear evidence that cementocytes have a function in tissue homeostasis of cementum comparable to that of osteocytes in bone. Recent studies have established an important role for the secreted glycoprotein sclerostin, the product of the SOST gene, as an osteocyte‐derived signal to control bone remodelling. In this study, we investigated the expression of sclerostin in cementocytes in vivo as well as the expression of SOST and sclerostin in periodontal ligament cell cultures following induction of mineralization. Material and Method: Immunolocalization of sclerostin was performed in decalcified histological sections of mouse and human teeth and alveolar bone. Additionally, periodontal ligament cells from human donors were cultured in osteogenic conditions, namely in the presence of dexamethasone, ascorbic acid and β‐glycerophosphate, for up to 3 wk. The induction of calcified nodules was visualized by von Kossa stain. SOST mRNA was detected by real‐time PCR, and the presence of sclerostin was verified using immunohistochemistry and western blots. Results: Expression of sclerostin was demonstrated in osteocytes of mouse and human alveolar bone. Distinct immunolocalization in the cementocytes was shown. In periodontal ligament cultures, following mineralization treatment, increasing levels of SOST mRNA as well as of sclerostin protein could be verified. Conclusion: The identification of SOST/sclerostin in cementocytes and mineralizing periodontal ligament cells adds to our understanding of the biology of the periodontium, but the functional meaning of these findings can only be unravelled after additional in vitro and in vivo studies.