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OBJECTIVE@#To evaluate the digital workflow coupling conic retention for the immediate restoration of adjacent posterior implants.@*METHODS@#The patients with adjacent teeth missing in the posterior jaw seeking for implant restoration in the Department of Implantology, Peking University School and Hospital of Stomatology from March, 2017 to February, 2018 were recruited. After implant placement and commercial conic retention coping delivery, the patient had an intraoral scan for digital impression, and the computer-assisted design/computer-assisted manufacturing (CAD/CAM) technology was used for the fabrication of the immediate splinted prosthesis, which was made of polymethyl methacrylate (PMMA) and loaded immediately after delivery. Six months later, all the temporary prostheses were replaced by the permanent ones made of monolithic zirconia with CAD/CAM technology as well. The parallel periapical films were taken for the temporary and permanent prostheses post-delivery. The clinical effect of this workflow was evaluated by indices including the survival rates of implants and prostheses, the change of marginal bone level, and the implant-related and prosthesis-related complications; before the final restoration, the Visual Analogue Score (VAS) was used to evaluate the satisfaction of the patients.@*RESULTS@#Ten patients (4 males and 6 females, 55.5 years old for average) were recruited. Totally 34 implants were placed; 14 prostheses were fabricated, temporary and permanent, respectively. After an observation period from 4 to 14 months, the survival rate for implants and prostheses were both 100%; the marginal bone level of the implants were (1.06±0.97) mm and (0.96±0.82) mm, immediate post-operation and 6 months later, respectively. The difference was not statistically significant (P>0.05). Neither implant- nor prostheses- related complications were observed. And the VAS of the patients' satisfaction was 87.2.@*CONCLUSION@#For the adjacent posterior implants, the immediate prostheses manufactured by digital workflow, coupling conic retention, were clinically feasible and patient-satisfactory.
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Female , Humans , Male , Middle Aged , Computer-Aided Design , Patient Satisfaction , Prostheses and Implants , Prosthesis Implantation , WorkflowABSTRACT
Over the past few decades, surgical treatment for spinal tumors has experienced many technological innovations, including surgical methods, implantations, biological agents, computer-assisted navigation equipment and so on. The real-time intraoperative imaging guidance and 3D imaging reconstruction provide theoretical and technical support for accurate location and resection of spinal tumors. The intraoperative navigation has been widely introduced into the surgical treatment of orthopaedic diseases, such as pedicle screw placement, pelvic fracture fixation, etc., and achieved satisfactory effectiveness. The application of navigation technology platform has greatly improved the minimally invasive treatment and precise resection of spinal tumors, and reduced the radiation exposure injury during operation. In this review, we sum up the effectiveness, safety and development prospects of navigation technology for spinal tumor treatment.
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Objective Based oncomputer-aided design (CAD) technology, we compared the optimized method of locating inserting point (2 cm lateral to and 1 cm below angulus oris) with traditional ones and assessed its clinical value by simulating foramen ovale (FO) cannulation. Methods Skull CT data of 100 primary trigeminal neuralgia patients were used in this study and three-dimensional reconstruction with FO cannulation simulation were conducted. With self-control test method, each patient was divided into three groups: group of optimized insertion point (method O) : point 2 cm lateral to and 1 cm below angulus oris as the insertion point; group of traditional entry point A (method A) : 2.5 cm lateral the angulus oris as the insertion point; group of traditional entry point B (method B) : intersecting the external extension of angulus oris and the vertical line of the lateral eye angle as the entry point. Puncture simulation was performed along connecting line of insertion point and the central point of the FO. We recorded results of simulation and measured the available area and short diameter of FO in the direction of puncture. Results The cases that the puncture route was obstructed of methods O, A and B were 15, 28 and 31, respectively. The occlusion rate of method O was significantly lower than those of methods A and B (P ＜ 0.01 or P ＜ 0.05). The available area of methods O, A and of B were (9.45 ± 6.57) mm2, (6.91 ± 5.96) mm2, (6.59 ± 5.86) mm2, respectively. The available area of method O was significantly larger than those of methods A and B (P ＜ 0.01 or P ＜ 0.05). The short diameters of methods O, A and B were (2.25 ± 1.04) mm, (1.81 ± 0.97) mm, (1.71 ± 0.92) mm, respectivtly. Short diameters of method O was significantly longer than those of methods A and B (P ＜ 0.01 or P ＜ 0.05). Conclusion compared with the traditional positioning method, the optimized method can provide better condition for puncture through Hartel approach.
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Digital technology is a new trend in implant dentistry and oral medical technology. Stereolithographic surgical guides, which are computer-guided implant placement, have been introduced gradually to the market. Surgeons are attracted to this approach because of it features visualized preoperative planning, simple surgical procedure, flapless implant, and immediate restoration. However, surgeons are concerned about the accuracy and complications of this approach. This review aims to introduce the classification of computer-guided implant placement. The advantages, disadvantages, and accuracy of this approach are also analyzed. Moreover, factors that may affect the outcomes of computer-guided implant placement are determined. Results will provide a reference to surgeons regarding the clinical application of this approach.
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Dental Implantation, Endosseous , Patient Care Planning , Surgery, Computer-AssistedABSTRACT
Objective To introduce a self-developed computer-assisted design/rapid prototyping and guidance system used for precise placement of the acetabular component in total hip arthroplasty.Methods We collected the preoperative pelvic CT scanning data of 10 hips with aeetabular dysplasia that had undergone primary total hip arthroplasty from January 2016 to January 2017.The total time for import of radiographic images,model reconstruction,model segmentation,acetabular component position design and STL model export was calculated and compared between our self-designed software and Mimics vl 7.0.Three kinds of STL model from each case were imported into our self-developed 3D printing device,Stratasys Objet30 and Stratasys Demension SST1200es respectively for rapid prototyping.The printing efficiency and accuracy were compared among the 3 printers.The accuracy of placing acetabular component with guidance system was evaluated.Results The average time forpreoperative planningwas7.7±1.3 minbyourself-designedsoftware and 52.5 ± 15.9 min by Mimics v17.0,showing a significant difference (P ＜ 0.001).In morphological point-based comparison for each case,the 3D models exported by the 2 different kinds of software showed an average difference of 0.072 1 ± 0.069 1 mm.The average durations for rapid prototyping by the 3 different printers were 5.3 ± 0.6 h,10.8 ± 0.5 h,and 9.3 ± 0.6 h,respectively,showing significant differences (P ＜ 0.001).The guidance system resulted in precise placement.The locations of the acetabular component achieved by guide-assisted placement were not significantly different from the target ones (P ＞ 0.05).Conelusion Our self-developed preoperative planning software,rapid prototyping device and guidance apparatus for acetabular component placement may lead to good accuracy and high efficiency.
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BACKGROUND:Differences of knee anthropometry between individuals are significant, while preoperative templating is not accurate in predicting the prosthesis size. OBJECTIVE:To improve the accuracy of pre-operative plan in predicting the prosthesis size in total knee arthroplasty using digital technologies. METHODBetween January 2013 and May 2004, 50 patients (20 men and 30 women;aged 54-82 years;mean age, 67.8 years) received primary total knee arthroplasty for osteoarthritis and were retrospectively analyzed. According to the treatment, the patients were divided into two groups. The digital group, a series of 21 patients, underwent 64-row MDCT before total knee replacement. CT images were imported into Mimics, and three-dimensional models of femur and tibia were reconstructed. Then, computer-aided design files of different sizes of prostheses provided by the manufacturers were imported into Mimics, too. Surgical simulation of osteotomy and prostheses implantation were performed in Mimics, component size was determined by the contour of distal femur and proximal tibia. The control group, a series of 29 patients, underwent primary total knee arthroplasty using conventional approaches. The agreement between preoperative plan and the actual prosthesis size was assessed during the surgery. Postoperative X-ray of low limb was taken to evaluate the accuracy of sizing and the efficacy of digital technologies was assessed. RESULTS AND CONCLUSION:The intraoperative and postoperative evaluation showed inaccurate sizing of femoral and tibial components in 1 case in digital group and in 11 cases in conventional group. The accuracy of prediction was 95%in digital group and 62%in conventional group, with significant differences between the two groups (P<0.05). Four overhanging and two notching cases were observed in conventional group, but none in digital group. The digital technologies provide an effective means for accurate prediction of prosthesis size and personalized surgical simulation.
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BACKGROUND:In total hip replacements, aseptic loosening of uncemented femoral hip prosthesis is the main reason for the failure of artificial hip replacement, the prerequisite of reducing aseptic loosening of prosthesis is to increase fil ing area of femoral prosthesis in femoral cavity. OBJECTIVE:To obtain the fil ing rate of customized femoral prosthesis in femoral cavity and verify the validity of the methods of CAD/CAM/Robotic integration and the robot grind. METHODIn this paper, the CT data of femur were used to reconstruct three-dimensional model of femoral cavity. According to this model, a custom uncemented femoral hip prosthesis was designed, then the model of this custom prosthesis was imported into the CAD/CAM/Robotic software to generate cut path. After the cut path was imported into the robotic control er, the custom prosthesis can be fabricated, then this custom prosthesis was inserted into the femoral cavity, and the fil ing result of the custom prosthesis in femoral cavity was analyzed. RESULTS AND CONCLUSION:The experiment results showed that the customized prosthesis in femoral cavity achieved good fil ing result, the structure of femoral cavity resisted the rotation of the customized prosthesis in femoral cavity, and the customized prosthesis obtained stable fixation in the femoral cavity.
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Objective To evaluate the effect of computer-aided design of composite materials with epoxide acrylate maleic (E) and hydroxyapatite (H) in cranioplasty. Methods A total of 45 patients with cranium defects were treated with cranioplasty by using skull bone flaps made of composite materials including epoxide acrylate maleic (E) and hydroxyapatite (H) ,which was designed with computer aid according to individual requirements. The patients were followed up for 6-36 months. Results After cranioplasty with composite EH, there occurred subcutaneous fluid in one patient and mild bone collapse in one. The composite EH showed good histocompatibility, with no infection or rejection. Conclusion During cranioplasty, use of computer-aided design of composite EH takes advantages of good accuracy, short operation time, good biocompatibility and good clinical efficiency.
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OBJECTIVE:To establish a simple individualized dosage regimen of multiple oral dosing of Theophyllin. METHODS:Based on pharmacokinetic parameters,Excel function was used to design the dosage regimen of multiple oral dosing extravascular administration of one-compartment model with Theophylline as an example. RESULTS:The following parameters such as plasma drug concentration at any time (t) since administration of Theophylline,peak time,maximum steady plasma-drug concentration,minimum steady plasma-drug concentration,accumulation coefficient,fluctuation percentage,fluctuation amplitude,and dosage for children and the old could be obtained and the concentration-time curves were able to be drawn from the input data including physical and pathological parameters,dosage (X0) of Theophylline,interval ?,absorption rate constant (Ka),drug clearance rate (CL),absorption fraction (F) and apparent volume of distribution (Vd). CONCLUSION:The method adopted in our study is simple,reliable and intuitive,and it is applicable for the design of the individualized dosage regimen of Theophyllin.
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Objective:To build a three-dimensional finite element model of child temporomandibular joint including the mandible with chincap,and provide a basic condition for the study of the effects of chincap on the stress distribution of the base of mandible.Methods:The model was constructed from a child who accepted the treatment of chincap by ANSYS 5.6,using the reconstructive technique of spiral CT in combination with the three-dimensional finite element.The model consisted of 20045 bricks and 4442 nodes.On the model,mandible retraction was simulated under the different traction which included the different directions and magnitudes.Results:Three-dimensional model of the `Temporomandibular joint-mandible-chincap system of child' was established,which was better suited for the actual and practical situation of chincap in clinic,and the loading point and the different directions and magnitudes were determined by clinical application.Mechanical changes of various parts of the model in different working conditions could be simulated by means of adding different material properties and boundary conditions.Conclusion:The established model could be used for the study of stress distribution of chincap applying simulation.
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Objective: To design the ribozymes to cleave human TIMP 1 mRNA, and embed them into U 6snRNA to make them stable. Methods: Ribozymes were designed according to the “hammerhead structure” described by Symons.Computer was used to analyze the possible cleavage sites. Results: Three ribozymes targeting the nt123, nt299 and nt353 on TIMP 1 mRNA were designed. Embedding ribozyme in U 6snRNA had little effect on its binding with the substrate. Conclusion: Computer assisted design is indispensable in studying ribozyme. Embedding ribozymes in U 6snRNA may be a good way to solve the problems existing in ribozyme study. [