Abstract: Objective To study the effect of endogenous Farnesol by Candida albicans on enamel demineralization of Streptococcus mutans. Methods The sections of human enamel were divided into 5 groups. The first three groups were exposed to Streptococcus mutans suspension mixed with deionized water, liquid supernatant of Candida albicans for 24h at 37℃, and Candida albicans suspension. The fourth group was totally exposed to Candida albicans suspension as the experimental group, while the deionized water was used in control group under the same conditions．Enamel demineralization was evaluated by the amount of calcium in the liquid medium at 24,48,72h using atomic absorption spectrophotometry. Results The concentrations of calcium in groups with liquid supernatant of Candida albicans for 24h at 24,48,72h were respectively （80.26±1.63）、（81.14±1.24）、（78.31±0.76）μg/ml, which were obviously lower than other groups .There was significant difference between the experimental group and the control group (P<0.05). Conclusions The results show that endogenous Farnesol by Candida albicans has apparent effect on inhibiting enamel demineralization induced by Streptococcus mutans.

Objective To investigate the condyle-fossa relationship alterations in patients with skeletal class Ⅲ malocclusion following maxillary protraction therapy in mixed dentition by spiral CT scanning technique. Methods Fifteen patents with skeletal class Ⅲ malocclusion in mixed dentition, ranging in age from six years seven months old to ten years three months old, were treated with maxillary protraction. The patients underwent conventional 16 slice computed tomography scanning from PHILIPS company，and then 3D reconstruction was done to the skulls. Mid-sagittal images of the temporomandibular joints（TMJ）were evaluated for the possible changes in condyle-fossa relationship before and after treatment. Measurement items included the anterior joint space, the superior joint space, the posterior joint space, glenoid fossa depth and angulation of posterior wall of articular tubercle. Paired t test was applied to evaluate the differences. Results No statistically significant differences were found except superior joint space and posterior joint space before and after treatment. Conclusion The superior and poserior joint space decreased and condyle moves posterosuperiorly in patients with skeletal class Ⅲ malocclusion following maxillary protraction therapy in mixed dentition.

Abstract: Objective To study and evaluate the antibacterial effect of different concentrations of bioactive glass on three planktonic bacteria, Streptococcus sanguis plaque and mixed plague. Methods The Minimal inhibitory concentration (MIC) and Minimal bactericidal concentration (MBC) of bioactive glass on Streptococcus sanguis, Streptococcus mutans and Actinomyces viscosus were mensurated, and the pH value was measured at the same time. Bioactive glass with a MIC concentration was cultured with bacteria broth for 10mins, 30mins and 60mins, and then followed with plate counting protocol. Field emission scanning electron microscope (FE-SEM) was utilized to observe the 24h Streptococcus sanguis plague and 48h mixed plague after 10mins’ exposure to 37.5,75 and 150mg/ml bioactive glass. The effects of bioactive glass were visualized under confocal laser scanning microscopy(CLSM).Results Low concentration of bioactive glass was effective in inhibiting the bacteria from producing acid, and a significant difference(P<0.001) in the pH value was found between the control group and the test group. As the concentration of bioactive glass rose, bacterial aggregate became smaller and thinner. Conclusion Bioactive glass is effective in killing bacteria and it has inhibitory effect on both single and mixed plague. It also shows good sterlization and anti-acid ability even with low concentration.

Objective To study the variation law of the stress and displacement of teeth while exerting correctional forces of different magnitudes and directions, to provide relevant theoretical basis for the clinical treatment of the rotated teeth. Methods To establish a three-dimensional finite element model of the maxillary first premolar as well as its surrounding tissues, and to study the stress distribution in the clinical crown centers of the buccal and lingual face exerting a pair of equal size but opposite direction forces. Results Under different loading conditions, the stress concentrations were observed at the neck of the rotated maxillary first premolar tooth .With the increase of the force, the tooth displacement and the maximum stress value increased. Tooth displacement was larger when the Angle between the force and the X axis was smaller. Conclusion The force should be lighter, and the force direction and the X axis should be in parallel to prevent tooth from absorbing.

Objective To study the clinical satisfaction of a new style Nance arch without bands and its influence on periodontal tissue compared with traditional Nance arch. Methods 40 adolescent malocclusion patients with the need of mid-level anchorage were randomly divided into two groups, wearing two kinds of Nance arches. Visual Analogue Scales (VAS) was used to evaluate the degree of comfort wearing different Nance arches after 4 weeks. Plaque indexes, Gingival indexes and Probe depth of the upper first molar were collected after 4 weeks, 8 weeks and 12 weeks respectively. All data were subject to paired t-test and χ2 analysis. Results The degree of comfort wearing new style Nance arch was obviously higher than wearing traditional Nance arch and the periodontal index was also superior. Patients in new style Nance arch group suffered less from Gingival inflammation. Conclusion New style Nance arches are more favorable compared with traditional Nance arches in terms of degree of comfort and are more effective in reducing the influence on periodontal health and preventing gingival inflammation.

Abstract： Objective An in vitro study was conducted to measure the fracture resistance of teeth restored with casting post and core with acid etched surfaces. Methods Thirty-two recently extracted single root first premolars were endodontically treated and randomly divided into four groups. Crown truncation was performed at cemento- enamal junction 1.5 mm coronally. All of the specimens received casting post and core and metal all crowns. In the testing groups, root canal walls were acid etched respectively for 10 s,30 s and 60 s，while root canal walls in the control group were not. Each specimen was cemented with zinc phosphate cement, embedded in acrylic resin, and tested in a universal material testing machine. Results The fracture loads of roots were （2.981±0.102） kN、（3.097±0.084） kN、（3.128±0.071） kN in testing groups and （2.699±0.445） kN in control group. There was statistical difference between all testing groups and control group (P<0.05). Conclusion Acid etching on root canal walls results in significantly higher fracture resistance of roots after post-core and crown restoration.

Abstract Objective Through observation and comparison of piezosurgery and round bur applied in the implant surgery, including Onlay bone grafting, sinus lift, bone splitting, this research was aimed at seeking the advantages and the key points to use piezosurgery. Methods 80 operation areas of 78 patients from Department of Implantation,Changzhou Stomatological Hospital were operated with the piezosurgery and round bur during 2006-2012, piezosurgery 42 cases and round bur 38 cases. Usethe VAS to record the postoperative pain 6 hours, 24 hours and 3 days after operation. Using the SPSS11.5, all clinical data,including ranked data were analyzed by Mann-Whitney-Wilcoxon test. Results 6 hours after the operation, the mean score of VAS in the piezosurgery group（3.98±2.16）was lower than that of the round bur group（4.79±1.95）with statistically significant difference. 24 hours after the operation, the mean score of VAS in the piezosurgery group（2.35±1.86）was lower than that of the round bur group（3.21±1.76）with statistically significant difference. Conclusion Compared with round bur, using piezosurgery can decrease the occurrence rate of postoperative pain in short term.

Abstract: Objective To investigate the antibacterial effects of two kinds of silver colloid nanoparticles which were prepared with glucose and sodium hypophosphite against standard strain and fluoride–resistant strain of Streptococcus mutans. Methods Two kinds of silver colloid nanoparticles were prepared by reducing silver nitrate with glucose and sodium hypophosphite as reducing agents. We used the disk diffusion method and broth microdilution method to find out the antimicrobial properties of these two silver nanoparticles to standard strain and fluoride–resistant strain of Streptococcus mutans. Results The mean diameters of inhibition zone of the former nanoparticles to test bacteria were 20.87±0.66 mm、19.68±0.86 mm respectively，minimum inhibitory concentrations (MICs）were （2.08±0.90） μg/mL、（2.60±0.90） μg/mL；For the latter nanoparticles，diameters of inhibition zone to test bacteria were （14.86±0.43） mm、（14.19±0.50） mm，MICs were （35.15±12.18） μg/mL、（56.24±24.36） μg/mL. Between the two kinds of silver colloid，antibacterial property of the former was higher than the latter and the difference was quite obvious. There was no significant difference in antibacterial property against standard strain and fluoride–resistant strain in one kind of solution. Conclusion Two kinds of silver colloid nanoparticles made with glucose and sodium hypophosphite as the reducing agents respectively exhibited high antibacterial effects against standard strain and fluoride–resistant strain of Streptococcus mutans，and the former was better than the latter.

[Abstract] Objective To explore the mechanism of apoptosis in the labial glands of patients with primary Sjogren’s syndrome(pSS). Methods Samples from 70 clinically suspected primary Sjogren’s syndrome (pSS) patients were collected. Based on the results of labial gland biopsy, 40 cases of positive pathological grade served as experimental group, and the rest 30 were classified as control group. Immunohistochemistry was used to examine Bax protein in labial glands of two groups. The homogenate of labial glands was prepared; the mitochondria were extracted; the CytC content was detected. SPSS14.0 software package was used for statistical analysis. Results In experimental group, the expression of Bax protein mainly existed in epithelium and ductal epithelial cells (with IOD being 51.20±0.57) while in the control group, positive staining was mainly found in stromal cells(with IOD being 22.03±0.25), and there was a significant difference between two groups. In experimental group, the content of CytC in cytoplasm was 5.98±0.24, and the content of mitochondrial CytC was 0.44±0.14, while those of the control group were respectively 2.19±0.29 and 0.87±0.09. There were significant differences between them. Conclusions The pathogenesis of pSS is related to the apoptosis that is induced by Bax protein and CytC.

Objective To analyze whether nasopharyngeal, palate-pharyngeal and glossopharyngeal airways differed among skeletal class Ⅱadults with different vertical facial types，and to study the association of vertical facial types with different parts of upper airway. Methods Cone-beam computed tomography（CBCT）records of 64 adult skeletal class Ⅱ patients (34 male and 30 female) were used to evaluate airway dimensions (sagittal diameter，transverse diameter，length，sectional area) and volume (in each part including nasopharynx, palatopharynx, and glossopharynx).The samples were divided into three groups according to the GoGn-SN angle(low angle group,average angle group,and high angle group).Upper airway differrences were measured and compared among three groups. Results The glossopharyngeal length and volume, as well as palate-pharyngeal Spns of high angle group were statistically significant different with those of low and average angle group（P<0.05），while no difference was found between low angle group and average angle group (P>0.05).Compared with the low and average angle groups, high angle subjects exhibited decreased LPns and Lu with statistically significant difference (P<0.05). No statistically significant difference in upper airway width was observed in nasopharynx, palatopharynx, and glossopharynx among patiens with different vertical skeletal facial types. Conclusions The vertical skeletal patterns may be contributory factors for the variation of upper airway stucture, especially for the nasopharynx and palatopharynx.It has relatively small influence on nasopharynx .

Abstract: Objective To evaluate the survival rates of the restorations for wedge-shaped defect with Dream Color nanometer resin and Fuji Ⅱ resin-reinforced glass ionomer. Methods 200 patients with 479 wedge-shaped defect teeth were selected and randomly divided into two groups. 105 patients with 246 defect teeth were treated with Fuji Ⅱ resin reinforced glass ionomer(glass group),and the other 95 patients with 233 defect teeth were treated with Dream Color nanometer resin (resin group). All the patients were recalled to evaluate the restoration efficacy two years later. Results 183 patients(with 446 teeth) were evaluated two years after restoration. The total failure rate，completely broken rate and secondary to pulpitis rate in the Glass group were significantly lower than those in the Resin group (for all the three kinds of rates,p<0.05); the edge broken rate of the glass group was significantly higher than that of the resin group (p<0.05).Conclusion Dream Color nanometer resin and resin reinforced glass ionomer have their own advantages for wedge-shaped defect repair. The former is better for patients with high aesthetic requirements or poor toothbrushing habits, while the latter has benefits for protecting dental pulp.

Objective　To evaluate the clinical effect of Er,Cr:YSGG laser on soft tissue surgery. Methods　Twenty-nine cases were treated by Er,Cr:YSGG laser on soft tissue surgery without local anesthesia and sutures required. The effect after Er,Cr:YSGG laser treatment was evaluated. Results　After laser therapy without other special treatment，there was no pain，no bleeding except one epulis，and there was no infection．Wound healed after five to seven days except one epulis，without obvious scars. Conclusion　Er,Cr:YSGG laser provides a more efficient, secure, convenient, and comfortable treatment.

0bjective To analyze the maxillofacial morphological characteristics of patients with abnormal upper lateral incisors．Methods 120 patients with abnormal upper lateral incisors were divided into two groups and were analyzed cephalometrically: group A:60 cases of typeⅠpeg-shaped upper lateral incisors; group B: 60 cases of type Ⅱ microdontia upper lateral incisors．Students’t-test was used for data analysis．Results Group A showed significantly smaller SNA、ANB、Ptm-A(mm)、U1-SN、L1-NB、UL-EP and increased SNB、PP-GoGn、SN-MP、Y axis、U1-L1、U1-NA、L1-MP and Z angle（P<0.05）while Group B showed significantly smaller SNB、PP-GoGn、SN-MP、SN-MP、Y axis、U1-L1、angle and increased ANB、L1-NB、L1-MP（P<0.05）.Conclusions Most patients with TypeⅠpeg-shaped upper lateral incisors showed Class Ⅲ skeletal pattern with retrusive maxilla and most patients with Type Ⅱmicrodontia upper lateral incisors showed Class Ⅱ skeletal pattern with retrusive mandible. Patients with the two types of abnormal upper lateral incisors showed different maxillofacial morphological characteristics.

Objective To establish the database of teeth and dental arch by CT 3D-measurement on permanent normal occlusion of the youth in Harbin, and to provide practical basis for the clinical application. Methods The untreated normal occlusion of 50 Harbin youth aged 18-25 were evaluated by means of the spiral CT and AW4.2 workstation. Some diagnoses items were measured, and dentition indexes and linear correlation of normal occlusion were obtained. Results ①The width, angle, latero-length of the dental arch in men were significantly larger than those in women.② In normal occlusion, dental arch was generally symmetric, but there was asymmetry to a small degree. Right canine latero-length in men was larger, while left molar latero-length in women was larger. ③There was no marked sexual difference showed in tooth size. ④The sexual dimorphism was found in Bolton＇s index of anterior teeth group. ⑤The correlation analysis of inter-arch tooth size revealed that there were significant positive relationships between upper anterior teeth group and lower＇s and between upper overall teeth group and lower＇s, and additionally sexual differences were found in incisor teeth group and lateral teeth relationship. Conclusion ①The dental arch of men is wider than that of women.② Dental arch is not exactly symmetric, and superior sides were noticed in right canine part of men and left molar part of women. ③ When we estimate the lateral teeth size, appropriate references are upper incisor teeth for men and lower incisor teeth for women.

Objective To assess the perceptions of patients, parents, and orthodontists of white spot lesions during orthodontic treatment. Methods A questionaire survey of the perceptions of orthodontic patients (n＝ 247), parents (n ＝ 223), and orthodontists (n ＝ 51) was carried out, and then the results were analyzed. Results Three groups all thought that white spot lesions reduced the aesthetic of teeth, and that the major responsibility for the occurrence of white spot lesions was on the patients（P＜0.01）. The main reasons of white spots were incorrect way of brushing teeth or insufficient time or times of brushing teeth. Conclusions Patients, patients’ parents, and orthodontists all believed that white spot lesions reduced the aesthetic of teeth, and that the major responsibility for the occurrence of white spot lesions was on the patients.

Oral-facial-digital syndrome type-Ⅰ(OFD type-Ⅰ) is a rare congenital syndrome characterized by eccyliosis and malformations of the oral cavity, face and bones. A case of OFD I type with cleft lip and palate, the teeth deformities, short syndactyly, congenital heart and brain hypoplasia was reported, combined with review of the literature to summarize its etiology and the treatment so as to provide a reference for clinical diagnosis and treatment.

Nonresolving inflammation (NRI) plays an important role in the initiation、development and malignant transformation of tumors. The tumor microenvironment is a nonresolving inflammatory microenvironment, which would promote tumor malignant transformation induced by chronic, repeated and faintly inflammatory stimulations. For the regulatory mechanisms of cancer cells to the cells around them, the exosomes functioning as messengers are drawing more and more attentions. Currently, researchers believe that miRNAs can also mediate the cell-cell communications as signal molecules. In the tumor micro-inflammatory environment, the tumor-derived exosomes-miRNAs exhibit critical functional regulation on the adjacent cells. Hence, exploring the formational and functional mechanisms of exosomes-miRNAs would help to unveil the core of immune and inflammation in tumor microenvironment.

【Abstract】 Objective To compare the long-term treatment effects of the young permanent teeth root point induction forming technique used the calcium phosphorate cement root canal sealer and the calcium hydroxide cataplasm. Methods To select 181 patients, 205 troubles teeth in total, which were suitable for using the root point induction forming technique. The above were divided randomly into test group and control group, applying the root point induction forming technique used the calcium phosphorate cement root canal sealer and the calcium hydroxide cataplasm for treating respectively. The long-term treatment effects were investigated 2 years later. Results To be analyzed with statistics,the success ratio of test group and the control group respectively is 91.74%,79.17%. the difference has significance(P<0.01). Conclusion Extreme carries on the root point induction forming with the calcium phosphorate cement root canal sealer is one kind is simple，effectively，the reliable method of treatment，may promote the use.