Abnormal implant placement is a common challenge in clinical work, including root direction, occlusion direction, mesial direction, distal direction, buccal (lip) direction, tongue (palate) direction, a total of 6 directions. Clinicians should pay great attention to the risk of many complications due to improper placement of implants. Understanding the etiology is the premise to effectively prevent the complications of implant restoration, and this article will discuss the causes, the classification of complications and related treatment principles and treatment plans from 6 different directions of abnormal implant positions.

Objective:To analyze the stress distribution in the fixed denture of edentulous maxilla supported by 6 implants at different implant position.Methods:The skull of a volunteer with total anodontia and moderate alveolar bone absorption was scanned by CBCT.Computer software,Abaqus 6.9,Geomagic Studio 12,and Mimics10.01,were applied for data processing and reconstruction of a 3D finite element model of implant-supported fixed denture with 6 implants in different location;and then,the stress distribution was analisized.Results:3D finite element model of edentulous maxillary implant-supported fixed bridge with good geometric similarity was established.The implant neck bone interface stress value of the distal of the implant fixed bridge at the molar area,the stress concentration area,was the maximum.The main stresses were compressive in the cortical bone adjacent to the mesial or the distal implants.The shift of the denture decreased from anterior to posterior.In model Ⅰ (implants at 13,15,17,23,25 and 27) distal cantilever was not used and the stress distribution was the evenest.Conclusion:The implant position at 13,15,17,23,25 and 27 of edentulous maxillary 6-implants-supported fixed bridge was the best for the stress distribution among the 8 models.

Objective To present a medical image transmission scheme based on fast healthcare interoperability resources(FHIR) proxy gateway which can enable medical personnel to access the hospital's medical imaging system via the Internet using mobile terminals,and then raise the medical staffs' working efficiency.Methods RESTful WebServices as the interoperability mechanism of image data was used in combination with FHIR image resource model and construct an intermediate gateway to three-tier network architecture,in order to solve the problem of transmitting image data to mobile terminals through gateway via the hospital's network.Results During its half-year trial run,the Internet mobile terminal reading system based on this method ran stably and was in good condition,in the actual hospital environment.Conclusion The gateway method is simple,flexible,and can fully support the mobile terminals' access to the background image data center.

UNLABELLEDOBJECTIVE To evaluate the aesthetic effect of restorations with custom pressable metal ceramic abutments for defective soft and hard tissue in the maxillary anterior zone.

METHODSFifty-two patients with missing anterior teeth in the maxillar were selected, who had problems such as exposure of abutment metal, excessively large angle deviation, excessively long ceramic crown and missing gingival papilla, affecting the aesthetic effect of implant denture. Custom pressable metal ceramic abutments were made on the conventional castable metal abutment surface and restored with all-ceramic crowns to overcome the blackness at the implant neck.

RESULTSClinical evaluation for aesthetic effects 3 and 6 months after the restorations were placed. In 63 restorations of 52 patients, the blackness at the implant neck were eliminated and the aesthetic effect were ideal. The gingival was in healthy condition, showing no further gingival retreat or inflammation around the implant denture.

CONCLUSIONCustom pressable metal ceramic abutments can effectively improve the aesthetic appearance of the implant denture in maxillary anterior zone.

Ceramics ; Crowns ; Dental Abutments ; Dental Implants ; Dental Porcelain ; Esthetics ; Humans ; Maxilla ; Metals

Objective To study the efficiency of a new type of lithotripsy fixed plier in holmium laser lithotripsy. Methods From January 2013 to May 2016, 148 patients with nephrolithiasis in our hospital were randomly divided into two groups to perform percutaneous nephrolithotomy, holmium laser combined with lithotripsy by lithotripsy fixed pliers was performed in 74 patients in Group A to remove the stones. 74 patients in Group B simply took holmium laser lithotripsy to remove the stones. Analyzed operation time, lithotripsy time, complications, surgical efficiency of the two groups and so on. Results The total operation time of group A was 55-180 minutes with an average of (95. 00±2. 19) minutes. The lithotripsy time was 25-125min with an average of (47. 50±1. 41) min. Patients in group B had a total operation time of 50-185 minutes with an average of (100. 00±2. 28) minutes; The lithotripsy time was 25-100 minutes with an average of (59. 90±1. 65) minutes. There was no significant difference between the two groups in the overall operation time, and the lithotripsy time was significantly different. Conclusion The holmium laser combined with lithotripsy fixed pliers can reduce the lithotripsy time and improve the lithotripsy efficiency as compared with pure holmium laser lithotripsy.

Objective:To evaluate the effects of the changes in respiratory status on gated stereotactic radiotherapy under free breathing guided by real-time position management (RPM).Methods:This study simulated the baseline shift, change in respiratory rate, end-expiratory delay, end-inspiratory delay, and irregular breathing using an in-house developed motion phantom. Moreover, this study analyzed the correlation between the changes in the above states of three plans, three-dimensional conformal radiotherapy(3D-CRT), intensity modulated radiotherapy(IMRT), and volumetric modulated arc therapy(VMAT) and the position of the ball at the center of the motion phantom (L) and the exposed dose of the phantom in the ionization chamber (the dose).Results:The in-house developed phantom presented high setup repeatability and measurement stability. There was a positive correlation between L and the baseline shift ( r = 0.99, P < 0.01). The change in the dose was less than 4% when the baseline shift was less than the setup error, while the dose declined rapidly and was negatively correlated with the baseline shift otherwise ( r= -0.95, P < 0.01). Moreover, there was statistically significant difference in dose when the baseline shift exceeded the setup error or not ( Z = -3.06, P < 0.01). There was no significant difference in the rate of the dose affected by baseline shift in the three plans ( P > 0.05). The changes in respiratory rate had little effect on L and the dose. Both end-inspiratory delay and end-expiratory delay reduced the planned dose of the three plans, with a maximum decrease of up to -1.74%. Furthermore, the end-inspiratory delay has greater effects on the planned dose than the end-expiratory delay( Z = -2.67, P< 0.01). However, there was no significant correlation between the dose and the delay duration ( P > 0.05), and no significant difference in the rate of the planned dose of the three plans affected by respiratory waveform change ( P > 0.05). Irregular breathing had greater effects on the dose. Specifically, the dose from six repeated measurements of 3D-CR, IMRT, VMAT was (709.68±180.00), (751.40±127.16), and (750.00±185.60) cGy, respectively, all less than the prescribed dose with a poor consistency. Conclusions:The changes in the patients′ respiratory status will reduce the dose, especially when the baseline shift exceeds the setup error threshold or large respiratory waveform variation corresponding to irregular breathing occurs. Moreover, there is no correlation between the decrease in the dose and the radiotherapy technology.

Objective:To explore the application effect of online and offline mixed teaching based on DingTalk platform in clinical practice teaching of respiratory department.Methods:The Batch 2016 ( n= 40) and Batch 2017 ( n=47) undergraduates of clinical medicine in Qiqihar Medical College were selected as the research objects, and they were divided into a control group and a research group. The control group adopted traditional offline theoretical teaching, while the research group adopted online-offline mixed teaching, focusing on teaching design and teaching objectives, teaching subjects, teaching resources, network platforms and teaching activities (classroom learning and evaluation). The theoretical and practical test scores of the two groups of interns were compared, and the evaluations of the students in the research group on the effect of online and offline mixed teaching were collected. Excel 2013 was used to sort out the data, and R software was used for data processing and statistical analysis. T-test was used for measurement data and Chi-square test was used for counting data. Results:The operational test scores [(28.16±1.70) points] and theoretical scores [(82.07±6.40) points] of the students in the study group were higher than those in the control group [(23.35±2.88) points and (76.20±5.67) points], with significant differences ( P<0.001). Compared with the students in the control group, the students in the research group were more satisfied with the mixed teaching method. Conclusion:The online and offline mixed teaching is conducive to improving students' comprehensive performance, learning effect, and promoting students' clinical diagnosis and treatment skills, self-study, innovation abilities and clinical competence.

The standardized workflow of computer-aided static guided implant surgery includes preoperative examination, data acquisition, guide design, guide fabrication and surgery. Errors may occur at each step, leading to irreversible cumulative effects and thus impacting the accuracy of implant placement. However, clinicians tend to focus on factors causing errors in surgical operations, ignoring the possibility of irreversible errors in nonstandard guided surgery. Based on the clinical practice of domestic experts and research progress at home and abroad, this paper summarizes the sources of errors in guided implant surgery from the perspectives of preoperative inspection, data collection, guide designing and manufacturing and describes strategies to resolve errors so as to gain expert consensus. Consensus recommendation: 1. Preoperative considerations: the appropriate implant guide type should be selected according to the patient's oral condition before surgery, and a retaining screw-assisted support guide should be selected if necessary. 2. Data acquisition should be standardized as much as possible, including beam CT and extraoral scanning. CBCT performed with the patient’s head fixed and with a small field of view is recommended. For patients with metal prostheses inside the mouth, a registration marker guide should be used, and the ambient temperature and light of the external oral scanner should be reasonably controlled. 3. Optimization of computer-aided design: it is recommended to select a handle-guided planting system and a closed metal sleeve and to register images by overlapping markers. Properly designing the retaining screws, extending the support structure of the guide plate and increasing the length of the guide section are methods to feasibly reduce the incidence of surgical errors. 4. Improving computer-aided production: it is also crucial to set the best printing parameters according to different printing technologies and to choose the most appropriate postprocessing procedures.