Objective To study the effects of oral fluoride-containing environment on titanium surface oxide film properties and corrosion behaviors. Methods The pure titanium samples were immersed in artificial saliva with different fluorine concentrations, and the fluorine-free artificial saliva was used as the control group. The test samples and soaking solutions after 7 days were collected, and the titanium surface oxide film compositions were analyzed by X-ray photoelectron spectroscopy (XPS). Electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion behaviors of pure titanium samples in artificial saliva of different groups. The quantities of titanium ion release in soaking solutions of different groups were detected by inductively coupled plasma optical emission spectrometer (ICP-OES). Results The analysis of XPS survey spectra showed that the contents of titanium and oxygen element on the titanium surface gradually decreased with the increase of fluorine concentration, whereas the content of fluorine element increased correspondingly. The analysis of XPS high resolution spectra showed that the content of TiO2 on the titanium surface decreased with the increase of fluorine concentration. According to the Nyquist plots, Bode-phase diagrams and equivalent circuit fitting data obtained by EIS test, the corrosion resistance of titanium oxide film decreased with the increase of fluorine concentration, and the corrosion behavior of titanium increased gradually. ICP-OES revealed a significant increase of titanium ion release as the concentration of fluoride increased. Conclusions The oral fluoride-containing environment can damage the titanium surface oxide film, accelerate the corrosion behavior, and in turn, induce the release of titanium ion. This effect is enhanced with the increase of fluorine concentration.

Researched on antibacterial properties of HAPw/nmZnO-nmCaO against Staphylococcus aureus and Pseudomonas aeruginosa in vitro. Material and methods:Prepared Staphylococcus aureus and Pseudomonas aeruginosa suspension,OD595=0.1.HAPw、Bio-oss、HAPw/nmZnO-nmCaO material suspension prepared with 1mg/ml of sterile pure water.Group A: 5 ml medium + 1 ml HAPw/nmZnO-nmCaO + 200ul bacterial suspension; Group B: 5 ml medium + 1 ml HAPw + 200ul bacterial suspension; Group C: 5 ml medium + 1 ml Bio-oss + 200ul bacterial suspension; D control group: 5 ml medium + 1 ml sterilized pure water + 200 ul bacterial suspension.Each group was incubate 20h in thermostat with temperature of 37℃,then the samples were diluted with a concentration gradient. The diluted mycelium was coated on the agar plate with 100ul and incubate 20h in thermostat with temperature of 37℃,the plate colonies were counted..Results:Staphylococcus aureus and Pseudomonas aeruginosa HAPw/nmZnO-nmCaO group had fewer colonies than HAPw, Bio-ose, control group(P＜0.001),there was no siginificant difference between HAPw, Bio-oss, and control group(P＞0.05).Conclusions:HAPw/nmZnO-nmCaO inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa. The inhibition of Staphylococcus aureus was stronger than that of Pseudomonas aeruginosa.

Abstract: Objective To evaluate the initial effect of a kind of universal adhesive on resin bonding of three different types of CAD/CAM machinable materials. Methods 20 pieces of each kind of ceramics (yttria-stabilized tetragonal zirconia polycrystals, resin nanoceramics and lithium disilicate glass ceramics) were made, of which the former two groups were sandblasted with alumina and the latter group were subjected to HF acid etching. Each group of ceramics is subdivided into two subgroups, treating with a universal adhesive (SBU) or not (Ctr). The adhesive specimens were produced and after immersed in water for 24h, shear bond strength (SBS) and modes of failure were determined. Surface morphology of sandblasted zirconia ceramics and resin nanoceramics and HF acid-etched lithium disilicate glass ceramics were observed by using a scanning electron microscope (SEM). Results SEM observation showed that, the sandblasted zirconia ceramics and resin nanoceramics and HF acid-etched lithium disilicate glass ceramics exhibited rougher surface morphology after roughening treatment. The initial shear strength of three kinds of ceramics applying with universal adhesive was significantly enhanced than that of roughened one. Conclusion Application of the universal adhesive Single Bond Universal can enhance the bonding strength between zirconia ceramics, lithium disilicate glass ceramics, resin nanoceramics and resin.

Objective This study evaluates the effect of site preservation on the preservation amount of alveolar bones to keep their height and width to a greater extent, using dentoalveolar distraction extraction (DDE). Methods Twelve beagle dogs were randomly divided into three groups. In experimental group extract the third premolars on one side of mandible, with dentoalveolar distraction, In control group 1 the third premolars were extracted traditionally without any site preservation as control group one (Natural healing, NH). For the other four dogs, the third premolars on one side of mandible were extracted as control group 2, following the Bio-Oss bone dust implant and guided bone regeneration (Bio-Oss +GBR, BOG). The X-rays were taken three months after tooth extraction, and the results were compared among different groups. Results Three months after tooth extraction, the alveolar bone resorption in the experimental group was significantly lower than that in the control groups 1 and 2. there was no statistical significance between the control groups 1 and 2. Conclusion The alveolar bone can be preserved to a greater extent by using dentoalveolar distraction extraction for site preservation.

Objective To investigate the relationship between the cross-sectional area of different connectors and the fracture resistance of three-unit polyetheretherketone fixed bridge , and discuss the minimum cross-sectional area of the connectors. Methods 30 pieces of freshly isolated teeth in the mandibular molar area were selected to make 15 pairs of models, which were randomly divided into three groups(A、B and C) with 5 in each group. The cross - sectional areas were respectively 5.0 mm2, 7.0 mm2 and 9.0 mm2 by CAD/CAM systems. The actual cross-sectional area of the connector was measured by vernier caliper. The fixed bridge was put on the model, fracture load was measured, the maximum load was recorded automatically by the computer , and the damage mode of the fixed bridge was observed. Results The average actual cross-sectional areas of three groups(A、B and C) were 5.40 mm2 ,7.62 mm2 and 9.73 mm2 respectively, the fracture resistances were (657.44+45.17) N, (877.94+71.11) N and (1244.64 +62.38) N. The one-way ANOVA and SNK revealed that there were statistically significant differences in fracture resistance between cross-sectional areas（P＜0.05）. The connectors of the fixed bridge was completely broken. Conclusions The connector is the weak area of the fixed bridge, and the fracture resistance of the fixed bridge can be increased by increasing the cross-sectional area of the connector. It is recommended that the cross-sectional area of three-unit polyetheretherketone fixed bridge be≥7.62 mm2.

Objective: To provide an implant reference method in measurement of posterior teeth region in the panoramic radiograph, and analyze the measurement error. Materials and Methods: From January 2017 to January 2018, panoramic radiographs of patients who received Osstem implant restoration treatments were collected at the Department of Implantology of Affiliated Hospital of Stomatology of Nanjing Medical University. The sizes of dental implants and cover screws were recorded in advance. The heights and diameters of the cover screws were calculated using the implant reference method. The calculated values were compared with the actual values to analyze the errors of this method. Results: Totally 93 panoramic radiographs from 54 patients were included in this study. The data sample accorded with normal distribution and there were no significant differences between the calculated values and actual values. Both vertical and horizontal absolute errors of measurements of posterior teeth regions in the panoramic radiographs using the implant reference method were less than 0.1mm. Conclusions: The implant reference method is applicable to the local measurement of the posterior region in the panoramic radiograph, and the measurement accuracy is relatively high.

Objective　To observe and compare the curative effect and difference of PRP combined allograft bone powder and autogenous iliac bone graft in the treatment of maxillofacial bone defect. Methods: 22 patients with maxillary lateral incisor and canine area of missing teeth and bone defect were randomly divided into A group and B group, 11cases in each. The two groups were treated with PRP combined with allograft bone powder or autogenous iliac bone graft to fill the bone defect area. Based on the CT data, the original defect area were evaluated in 1 months, 2 months and 3 months after the operation. Compared to the normal bone, the changes of bone growth in the filling area were measured. During the second dental implant operation, the bone was taken for pathological analysis, the bone quality was evaluated, and the ISQ value of the implant was measured. The initial stability of the implant was evaluated, and the grasping ability and biomechanics of the new bone to the implant were assessed. Results: Based on the precondition that the baseline data were comparable, in group A and B, the CT value was not statistically significant at all observation points after bone grafting operation(P > 0.05). The new bone CT value of group A was higher than the normal bone(P < 0.05),while the CT value of group B had no significant difference (P > 0.05).The ISQ value, which means initial stability of implants, had no significant difference between the two groups. New bone biopsy showed complex new bone and fibrous tissue with granular calcification in group A, but good quality cancellous bone with very few fibrous tissue and calcified impurities in group B. Conclusion: PRP combined with allograft bone filling bone defects can avoid extra invasive operation and surgical incision, more easily accepted by clinical treatment. Autogenous iliac bone graft has better biocompatibility and bone growth. Two methods of bone in dental implant both reflect good biomechanical properties and do not affect the initial stability of implants. PRP combined with allograft bone powder or autogenous iliac bone graft is selected according to the indications and clinical practice.

Objective　To explore the clinical effectiveness of modified maxillary sinus lifting used to treat patients who want implant restoration and don’t have enough bone mass in maxilary molar area. Methods 40 patients of dental implant section were chosen, whose height of alveolar bone in maxilary molar area was not enough and who were admitted to the Yancheng Dental Hospital from 2012 to 2016. They were randomly divided into the experimental group and the control group. 20 patients in the experimental group were treated with modified maxillary sinus lifting, in which 20 implants were placed. The other 20 patients in the control group were treated with traditional knock - type maxillary sinus lifting, in which 20 implants were placed. Then the follow-up prognosis of the 2 groups was compared and the follow-up lasted at least 12 months. Results: During the follow-up period, 40 implants of the 2 groups all got good osseointegration, and clinical effectiveness of the implant restoration was pleasing. Conclusions: With suitable indications, good clinical effectiveness can be achieved by carrying out modified maxillary sinus lifting and placing implants in meanwhile in maxilary molar area. The operation is simple,which can be applied in clinical practice.

Objective To observe the clinical effects of glass fiber pile and liquid resin in severe wedge-shaped defect restorations of premolar and anterior teeth. Methods 72 cases with severe wedge-shaped defect of the premolar and anterior teeth were selected. After the treatment of root canal, 24 teeth were randomly divided into three groups: Group A(mobile resin repair group), Group B(Z350 mobile resin + glass fiber pile repair group) and Group C(Z350 mobile resin + glass fiber pile + full crown restoration group). Comparative observation was conducted under the unified evaluation criteria. Results After 2 years’ observation,there was significant difference between Group A and Group B (P<0.05) . And there was no significant difference between Group C and Group B (P>0.05) . Conclusion The fiber pile can significantly improve the strength of the residual dental tissue of the severe wedge-shaped defect, and significantly improve its anti-foldability. But there is no significant effect on the repair of the severe wedge defect with the full crown, which deserves further discussion.

Objective To compare the clinical features and treatment results of multi-space infections of aral and maxillofacial region in patients with or without diabetes. Methods 104 patients with multi-space infections of aral and maxillofacial region treated from January 2014 to October 2017 were retrospectively analyzed. They were divided into diabetic group (n=38) and non-diabetic group (n=66) according to whether they had diabetes or not. The clinical features and treatment results of the 2 groups were compared. Results Compared with non-diabetic group, patients in diabetic group were much older, had much more infection spaces, and their blood glucose and neutrophil counts at admission were much higher; they had much higher detection rate of Klebsiella pneumoniae, their incisions of drainage were much more, hospitalization time was much longer, incidence of complications was much higher. The differences were statistically significant (P＜0.05). The main pathogeny in both groups was odontogenic infection, and there was no significant difference in the infected spaces between the two groups (P＞0.05). Conclusion Diabetic patients with oral and maxillofacial multi-space infections are more serious, showing more infections, more complications, more incisions of drainage, and longer hospitalization.

[Abstract] Objective Understand the condition of closure of the first permanent molars in children, and to explore the relationship and the role of various factors that may affect the pit and fissure sealant shedding. Methods 362 children in Harbin who were eligible for pit and fissure closure were selected, and the first permanent molars (1229) were closed with 3 kinds of pit and fissure sealants. The pit and fissure closure was examined at 3 and 6 months after surgery. Statistical analysis of the impact of children oral hygiene, eating habits, psychological factors, the number of surface caries, the kind of pit and fissure sealants five factors on pit and fissure shedding. Results After 3 and 6 months,checking a total of 353 children (1218); 3 and 6 months of pit and fissure expulsion rate was 10.0%, 11.9% respectively. The children of having the low frequency of dietary desserts and carbonated beverages, good oral hygiene, few facets, a quiet mind,and using with Helioseal F have low rate of the pit and fissure sealant shedding (P<0.05). Conclusion The pit and fissure sealant shedding of the first permanent molars of children aged 7-9 years were related to the kind of pit and fissure sealant, oral hygiene, facial number, psychological factors and eating habits.

Objective To summarize the pathogenesis features and clinical manifestations of osteonecrosis of the jaw associated with trigeminal herpes zoster and to provide scientific basis for the correct diagnosis and treatment through retrospective analysis. Methods Four cases were collected in the Department of Oral Surgery, Shanghai Ninth People's Hospital from 2011 to 2016 and 52 cases were collected from literatures. Then the retrospective analysis was conducted. Results The complication occurred mostly in middle-aged and elderly patients, with an age range of 6 to 86 and an average age of 54. These cases included 28 males and 19 females. The lesion could affect either the second (23 cases) or the third branch (23 cases) of the trigeminal nerve, or both (7 cases). 6 cases were complicated by HIV, 8 by malignant tumors. Conclusions Osteonecrosis of the jaw associated with trigeminal herpes zoster has a low incidence. Comprehensive consideration of its pathogenesis features and clinical manifestations can help to diagnose and treat it. For patients with cheek herpes zoster, it is advisable to treat them as soon as possible and to check for the presence of systemic diseases in order to prevent serious oral complications.

Objective　To summarize the clinical, pathological characteristics and treatment of Castleman’s disease (CD) in oral, maxillofacial and neck region. Methods　The CD cases in oral maxillofacial and neck region treated in Affiliated Stomatological Hospital, Nanjing Medical University from 2007 to 2017 were identified. The relevant clinicopathological and follow-up data were collected and presented. Results　Six cases of CD were identified with the histopathological subtype as hyaline-vascular type. Surgical resection of these masses was performed in all cases. No evidence of disease recurrence was found during the follow-up ranging from 2 months to 9 years. Conclusions　Castleman disease rarely occurs in oral, maxillofacial and neck region and its diagnosis relies on pathological examination. Surgical resection is a primary treatment with favorable prognosis.

To improve the clinical understanding of transmigration and impaction of mandibularm canine，CBCT imaging materials of transmigration and impaction of 6 mandibular canines within 5 patients were reported, and the imaging manifestations were analyzed and discussed. Among five patients, 1 male and 4 females were included, aged from 13 to 24. The CBCT imaging materials showed that most of canines lied in the mandibular body in a horizontal direction, among which one patient had transmigration and impaction of bilateral mandibular canines, the other four had transmigration and impaction of unilateral mandibular canine. The application of CBCT has important clinical value for comprehensive understanding of the incidence, clinical manifestation and antidiastole of transmigration and impaction of mandibular canine.

Abstract: With the development of modern oral implantology, more and more edentulous patients seek for implant-supported fixed restoration. In the edentulous mandible, to select the segmented restoration design or the one-piece restoration design is a problem that clinicians are very concerned about. This article discusses the related content of segmented restoration design from four aspects: physiology, mechanism, process and maintenance. It is concluded that in the edentulous mandible the segmented design is more reasonable. Only when the anatomical conditions are limited and the segmented design cannot be satisfied, the one-piece design is considered to be applied.

Abstract: With the development of our country's economy and the progress of dental implant technology, more and more edentulous patients choose denture implant to restore masticatory function and improve the quality of life. Implant-supported fixed prostheses of edentulous jaw is favored by patients because of its beauty, comfort, better recovery of chewing and pronunciation function. According to its superstructure design, it can be divided into complete and sectional prostheses. Complete design has good repair effect and good prognosis, which has many advantages, such as less implant number, flexible implant location, reasonable stress distribution, and the best biomechanical environment etc. Therefore, this article reviews the research progress of implant-supported fixed complete prostheses for mandible edentulous.

Guided bone regeneration(GBR) is an important method to repair defects around the implant, but there are still deficiencies in the effect of bone formation. In theory, the application of growth factors and bioactive materials to GBR in tissue engineering can improve the efficacy. However, at present, there are no clinical predictable therapies for the regeneration of defects around the implant. Even some studies have found that the long-term stability of osteogenesis after the use of growth factors in GBR is not consistent with the theoretically expected results. This problem must be solved to advance the application of growth factors. Through literature review and analysis, two possible reasons are given in the paper: the level of growth factor is too low in later phase and the degradation of the barrier membrane is accelerated by the growth factors. Based on this, the verification method is proposed to provide reference and basis for further research.

Maxillary sinus membrane perforation is the most common complication in the operation of sinus augmentation. Perforations can be classified into various categories by using different classification methods according to the location and the diameter of perforation, such as the classical sorting method, the simplified classification and the diameter classification. Each perforation classification also has its corresponding repair and treatment methods, including the classical approach, the buccal fat pad approach, the diameter perforation approach, the endoscopic approach and so on. If treated properly, the maxillary sinus membrane perforation would hardly have an impact on the survival rates of the implants inserted in these sites. Long-term success rates of the implants with perforated sinus membrane are comparable to those with intact sinus membrane.

Periodontitis are infectious diseases characterized by immune-mediated destruction of periodontal supporting tissues and tooth loss which is associated with microorganisms, host and environment.Matrix metalloproteinasas are key proteases involved in destructive periodontal diseases.The huge complexity of MMP functions within the protease web is crucial for many physiologic pathologic processes ,including immunity inflammation ,bone resorption,and wound healing .Evidence points out that MMPs assemble in activation cascades and besides their classical extracellular matrix substrates ,they cleave several signalling molecules -such as cytokines,chemokines,and growth factors ,among others-regulating their biological functions and /or bioavailability during periodontal disease.In this review,we provide a strong evidence that MMPs serve as regulators of periodontal inflammation.

In recent years, a variety of dental CAD/CAM systems have come out, which reflects the formation of an emerging prosthodontics technology. This article aims to review the development history and component of CAD/CAM technology, the mature chairside CAD/CAM systems as well as the prosthodontic materials, the clinical applications and the existing problems of chairside CAD/CAM technology.

The maxillary protraction device has become the most widely used orthodontic orthodontic treatment for skeletal class III malocclusion due to its low cost and excellent effect on maxillary growth. The effect of anterior traction is influenced by multiple factors, and it also affects the other structures of the craniofacial region. This article reviews the mechanism and timing of anterior traction, the factors that affect the effect of pretraction therapy, the influence of other structures after craniofacial treatment and the application in clinical practice.

Abstract:The skeletal Class Ⅱ of the following submandibular retractions often causes structural stenosis in the upper airway, and orthodontics often use the growth potential and functional correction to improve them. This article will review the relationship between bone Ⅱ, functional correction, growing development and the upper airway and the surrounding soft and hard tissues，hoping to provide some guidance for clinical diagnosis and treatment of patients with skeletal class Ⅱ malocclusion and upper airway stenosis.