Secondary caries is a disease that occurs on the tooth after the filling has been used for a period of time. Secondary caries is also the main reason for the replacement of dental restorations. Regardless of the material used for fillings, secondary caries cannot be completely avoided. The proportion of secondary caries is very high after filling in permanent teeth or primary teeth. Secondary caries mainly occurs because of the formation of micro cracks after filling. When the micro crack width exceeds 50 microm, saliva will enter the micro cracks between the filling and tooth tissue. The cariogenic bacteria in the saliva will grow when the environment of micro cracks is appropriate, thereby producing secondary caries. The prevention of secondary caries includes micro crack control, fluoride use, teeth cleaning, tooth decay and gum disease treatment, and regular checkups.
Dental Caries ; prevention & control ; Dental Restoration, Permanent ; Dentition, Permanent ; Fluorides ; Humans ; Phosphates ; Tooth, Deciduous

ObjectiveTo study the fluoride level of preschool children influenced by fluoride toothpaste. MethodsAbout 200 children aged 3～6 years old were involved in the test. The children of test group were given fluoride toothpaste while the children of control group were given non-fluoride toothpaste. After two months, hair samples were gasified by high temperature and were tested with fluoride-specific electrode. Urinary fluoride concentration and 24h urinary fluoride excretion were also conducted by using fluoride-specific electrode.ResultsIt shows that the 24h urinary fluoride excretion and the fluoride concentration in hair and urine of children in control group were apparently lower than those of children in test group.ConclusionFluoride toothpastes used by preschool children may result in the change of fluoride level in their bodies under the stability of their daily habits and living cir cumstances. Age is likely to be one of the facts that can influence the fluoride ingestion level.

砄bjective:To investigate the consistency of Streptococcus mutans and Streptococcus sobrinus isolates identified by colony morphology,biochemical tests and DNA base content analysis.Methods:46 clinical isolates (30 of S.mutans and 16 of S.sobrinus ) were identified by colony morphology,biochemical tests and determination of DNA base contents with reversed phase high performance liquid chromatography. S.mutans Ingbritt and S.sobrinus 6715 were used as the controls. Results:The DNA contents (G+C mol%) of S.mutans and S.sobrinus clinical isolates, identified by colony morphdogy and biochemical test, were 37.52 and 45.19 respectively,consistent with the expected 36～38 and 44～46 mol percent of G+C.Conclusion: S.mutans and S.sobrinus isolates,identified by colony morphology and biochemical tests ,were consistent with the DNA G+C content analysis. S.mutans and S.sobrinus can be easily and reliably identified by colony morphology and biochemical tests.

Construction of excellent course provides students with modern educational resources.Construction was focused on one main line,two dimensions,three aspects and with building frame,filling columns,putting into use,collecting feedback as well as modification and updating.Analysis was further made to avoid the common problems and phenomena such as displayed pages,limitation of share resources,low utilization of teaching resources and emphasis on construction,ignoring application and neglecting management.Some measures such as increasing the guidance of excellent courses and their promotion efforts,the establishment of an exchange platform and listening to feedback etc.are proposed.

0.05). S.sobrinus strains had significantly lower initial adhesive ability to saliva coated hydroxyapatite in the absence of sucrose than S.mutans (P

Objective To observe the influence of Baicalin and Octreotide on lung injury of rat with severe acute pancreatitis(SAP) and discuss the therapeutic effect and mechanism of the two medicines on SAP.Methods The improved Aho(?)method was adopted to pre- pare SAP rat models via retrograde injection of 3.5% sodium taurocholate to the pancreatic duct.The 135 SAP rat models after being pre- pared were randomly divided into the model group,Baicalin treatment group and Octreotide treatment group with 45 rats in each group;an- other 45 were selected to be the sham operation group which only received abdomen opening surgery.The above - mentioned groups were then randomly divided into 3h,6h and 12h groups with 15 rats in each group.Observed respectively at 3h,6h and 12h after operation,the mortalities of all rat groups followed by batch execution of rats,and then observed the gross pathological and pathological changes of lung. The tissue microarrays technology was applied to prepare the lung tissue microarrays sections.The changes in Bax and bcl-2 protein ex- pression levels of lung tissue of each group were observed via immunohistochemical staining and meanwhile the TUNEL method was applied to observe the lung cell category and apoptotic index changes of lung tissue in each group.Results The 12h survival of model group was 66,67% while those of Baicalin treatment group and Octreotide treatment groups were both 100%,indicating a marked difference(P＜0.05).Comparison of lung pathological score disclosed:The model group and Baicalin treatment group obviously exceeded the sham oper- ation group at various time points(P＜0.01);at 6h and 12h the Baicalin treatment group was obviously less than the model group(P＜0.05)and the Oetreotide treatment group less than the model group(P＜0.01).Comparison of Bax protein of lung in each group dis- closed:The Baicalin treatment group and Octreotide treatment group obviously exceeded the sham operation group and model group at 3h (P＜0.05),meanwhile the Baicalin treatment group obviously exceeded the Octreotide treatment group(P＜0.01).Changes of lung bcl -2 protein expression level of all groups disclosed:The model group and Baicalin treatment group obviously exceeding the sham operation group(P＜0.01)as well as the Octreotide treatment group(P＜0.05)at different time points,the Baicalin treatment group was obviously less than the model group at 6h(P＜0.05).The peak of apoptosis occurred to the Baicalin treatment group at 6h,but statistics showed no obvious difference among all groups at different time points(P＞0.05).Conclusions(1)Both Baicalin and Octreotide have protecting effect on SAP lung injury and their therapeutic mechanism is possibly related to apoptosis.The application of tissue microarrays in SAP pathological examination can save manpower and material resources,cut down the experimental cost and improve the experimental efficien- cy,thus worth popularizing.

The traditional discipline-centered curriculum design can neither keep up with developments of modern medical science nor reach requirements of the education reform in the new century.Since 2011,College of Stomatology in School of Medicine in Shanghai Jiao Tong University had developed ‘ disease oriented integrated curriculum system reform’ for students of long-term stomatology education.In view of the problems existing in the original curriculum system,the integrated curriculum system was set up by coalescing clinical medicine curriculum according to the related systems and oral medicine curriculum according to the developmental rules of diseases.Lectures were combined with discussion classes in the reform and performance appraisal system was changed from simplex judgments into comprehensive evaluations.At last,further considerations of promoting the reform based on the practice were proposed.

It is important to bring the principal role of medical students into full play and to develop their learning motivation and enthusiasm in order to obtain the satisfactory teaching effect in the clinical practice of preventive medicine and pediatric dentistry.Methods of timely summing-up,self-evaluation,making assumption and pair combination should be recommended.Cultivation for medical students should focus on the idea for diagnosis and treatment,skill of clinical practice and ability of doctor-patient communication.

Objective To investigate the satisfaction degree of students and teachers towards PBL teaching method and to provide a basis for continuing to carry out PBL teaching.Methods Anonymous questionnaires of PBL teaching method in teaching plan and procedure was conducted among 49students (2008 grade) and teachers.SPSS 13.0 software package was used to analyze the data and P ＜ 0.05 stands for statistically significant differences.Results Both students and teachers were satisfied.Teachers' evaluation scores of 17 projects were all higher than 4 points and students' evaluation scores of 13 projects were all higher than 4 points; scores for the rest projects were all higher than 3 points.Conclusions PBL teaching method combined with stomatology is effective and measures should be taken to strengthen the management of PBL teaching in stomatology.

Objective To investigate the value of prenatal ultrasound in diagnosis and treatment of twin reverse arterial perfusion (TRAP) syndrome. Methods A retrospective study was performed in 5 TRAP cases, including ultrasound images, clinical data and pregnancy outcomes. The sonographic characteristics were summarized. Results Five TRAP cases were diagnosed during 13 to 28 weeks' gestation and confirmed after birth. Color Doppler unltrasonography revealed retrograde umbilical artery perfusion towards acardiac twin. Two of 5 cases ended up in induced abortion, 1 in spontaneous abortion, 1 was delivered at 37 weeks' gestation after ultrasound-guided feticide of the acardiac twin and 1 was monitored closely with ultrasound and delivered alive at 32~(+4) weeks' gestation. Conclusion Prenatal ultrasonography has great applicative value for TRAP syndrome in early diagnosis, choosing optimal treatment and prognosis assessment.