BACKGROUND:Based on the principle of vertical tooth movement,a personalized orthodontic appliance is created through digital design combined with 3D printing,so that the personalized orthodontic appliance forms a support system with the individual incisors.With the help of the absolute support of the micro-implant,the single tooth is precisely controlled in a three-dimensional direction.OBJECTIVE:To design personalized orthodontic appliances with 11,12,21,and 22 intrusion and extrusion based on biomechanical principles,and analyze the safety of the personalized orthodontic appliances in terms of their movement effect on the teeth by means of the three-dimensional finite element method.METHODS:Three-dimensional finite element models of alveolar bone-periodontium-maxillary incisors-personalized cantilever micro-implant-connecting plates-personalized brackets in the maxillary anterior region(teeth numbers 11,12,21,and 22)were established using Mimics,Geomagic Wrap,SolidWorks,and Ansys Workbench software,respectively.Personalized orthodontic appliances with low pressure movement and extended movement were set up at each tooth position.The stress level of each component of the personalized orthodontic appliances was analyzed,and the tooth displacement and periodontal stress distribution were calculated under loading of 300 g tensile or thrust force.RESULTS AND CONCLUSION:(1)The maximum equivalent force on the personalized intrusion mobile orthodontic appliance was 162.90 MPa,and the maximum equivalent force on the personalized extrusion mobile orthodontic appliance was 239.57 MPa.The maximum equivalent stress on both devices was located in the vertical portion of the personalized bracket loading attachment.The equivalent stresses on each part of the personalized orthodontic appliance were all within the yield strength,and they had good safety.(2)The initial displacement of the teeth under the action of the personalized orthodontic appliances showed a tendency towards overall intrusion or extrusion,with the displacement in the vertical direction far exceeding that in the horizontal and sagittal directions.The equivalent stress peak appeared at the root tip or neck of the periodontal membrane,and the equivalent stress concentration area appeared in the periodontal membrane of the root apical region.(3)The results show that the personalized orthodontic appliance allows 11,12,21,and 22 to approximate either intrusion movement or extrusion movement,initially confirming the effectiveness of the personalized vertical movement orthodontic appliance.

BACKGROUND:Currently,the mandibular joint prosthesis manufactured at home and abroad needs to rely on screws to fix the condylar part of the prosthesis during the replacement process,and the retention hole is reserved to facilitate the operation during the operation.However,due to the lack of personalized jaw design,the reattachment plate may not fit the jaw,resulting in screw loosening and dislocation.Therefore,personalized condylar prosthesis replacement is of great value in the repair of the temporomandibular joint.OBJECTIVE:To design a personalized condylar prosthesis with an internal GYROID for mandibular condylar repair and reconstruction.METHODS:The GYROID structure was selected in the Rhinoceros 7 software with the single cell size of 6 mm and the wall thickness of 0.2,0.3,0.4,0.5,0.6,0.7,0.8 mm.The mechanical properties of the GYROID structure were analyzed by finite element method.3D printing of GYROID structural test specimens with different wall thickness(0.2,0.3,0.4,0.5,0.6,0.7,and 0.8 mm)was performed to test the mechanical properties of the specimens through room temperature compression experiments.A wall thickness value conforming to the range of mandibular mechanical properties was selected through finite element analysis and room temperature compression test results.An adult male mandibular CT data were used for inverse modeling to design a condylar prosthesis with an internal GYROID.Finite element analysis was used to simulate the movement of the apical staggered position and the opposite-blade jaw position after condylar prosthesis replacement.RESULTS AND CONCLUSION:(1)The results of finite element analysis and room temperature compression experiment showed that the elastic modulus of the GYROID structure increased with the increase of wall thickness.The elastic modulus of the GYROID structure with wall thickness of 0.5-0.7 mm was within the range of the elastic modulus of the mandible(1.5-4.0 GPa).Therefore,the 6 mm monocellular GYROID structural model with a wall thickness of 0.6 mm was selected for the design of the condylar prosthesis.(2)The results of finite element analysis showed that the stress distribution of mandibular model was symmetrical.The stress distribution of the two types of occlusion was roughly the same,and the stress peak was not significantly different.The stress concentrated in the neck of the condylar prosthesis,and the stress on the replacement side was slightly larger than that on the healthy side.The maximum equivalent stress of the whole internal fixation model was 269.34 MPa,and the maximum equivalent stress of the screw was 20.14 MPa.The equivalent stress and equivalent strain values of the prosthesis were greater than that of the opposite edge jaw position when the tooth tip was interlaced.The equivalent stress and equivalent strain values of the screw were smaller than that of the opposite edge jaw position when the tooth tip was interlaced.(3)The results showed that the design and retention of the personalized GYROID condylar prosthesis were good,which was consistent with the mechanical conduction of the mandible.

BACKGROUND:Porous structures based on triple periodic minimal surfaces are one of the most promising orthopedic biostructures,among which the Gyroid structure is characterized by high specific surface area,high permeability,and zero mean curvature.OBJECTIVE:To screen the wall thickness interval of TC4 bionic bone scaffolds with 4 mm single-cell Gyroid structure matching the elastic modulus range of cancellous bone of the mandible through finite element analysis combined with mechanical compression test testing.METHODS:The finite element model of the 4 mm single-cell Gyroid structure with different wall thickths(0.1,0.2,0.3,0.4,0.5,0.6,0.7,and 0.8 mm)was established.The equivalent elastic modulus of the Gyroid structure was analyzed,and the wall thickness interval of the Gyroid structure matching the elastic modulus range of the maxillary resinous bone was selected with different wall thicknesses of 0.2,0.3,0.4,0.5,0.6,and 0.7 mm,respectively.According to finite element analysis screening results,the material selected was Ti6Al4V.Selective laser melting was used to prepare 3D printed Gyroid structure specimens.The surface treatment was carried out by large-grained sand blasting and acid etching.The elastic modulus and compressive strength of the specimen were tested by mechanical compression experiment.RESULTS AND CONCLUSION:(1)The finite element analysis results showed that the equivalent elastic modulus of the Gyroid structure increased with the increase of wall thickness,and the equivalent elastic modulus of the Gyroid structure with wall thickness of 0.2-0.7 mm was within the range of the elastic modulus of the spongy bone of the mandible(1.5-4.0 GPa),which was used for 3D printing of the Gyroid structure specimen.(2)The mechanical compression test results showed that the elastic modulus and compressive strength of the Gyroid structural specimen increased with the increase of wall thickness,and the elastic modulus of the Gyroid structural specimen with wall thickness of 0.3-0.5 mm was within the range of the elastic modulus of the cancellous bone of the mandible.The compressive strength of the Gyroid specimen with 0.3-0.7 mm wall thickness was consistent with the mechanical properties of the mandible.(3)The results show that the Gyroid structure of 0.3-0.5 mm wall thickness is compatible with the range of elastic modulus of the mandible.

BACKGROUND:Condylar prosthesis replacement,as one of the surgical methods for the treatment of temporomandibular joint diseases,not only needs to restore the morphology and function,but also needs to ensure long-term stable application.OBJECTIVE:To design finite element analysis of a customized Gyroid condylar prosthesis.METHODS:Gyroid structure specimens with different wall thicknesses(250,350,450,550,650,and 750 μm)were designed by software.Finite element simulation compression experiments were carried out to test the elastic modulus of the specimens.The Gyroid structure wall thickness range that matches the elastic modulus of mandibular cancellous bone and whose pore size meets the osteogenesis conditions was screened out.This range was subdivided and Gyroid structure specimens were made using 3D printing technology.Mechanical compression experiments were carried out on a universal testing machine.The Gyroid structure wall thickness that meets the mechanical properties of mandibular bone,has an easier osteogenesis and a smaller strength was screened out by elastic modulus and compressive strength,and subsequent experiments were carried out.A three-dimensional model of a customized Gyroid condylar prosthesis was designed,and the finite element analysis of the blade jaw position and cusp interdigitation position of the model under natural occlusion was simulated.RESULTS AND CONCLUSION:(1)Finite element analysis results showed that with the increase of wall thickness,the elastic modulus of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 350,450,550,650,and 750 μm matched the elastic modulus of mandibular cancellous bone.Since the subsequent experiments needed to be subdivided into groups and the pore size of the 550,650,and 750 μm wall thickness group(pore size 800-1 000 μm)was within the osteogenesis range.Gyroid structure specimens with wall thickness of 550,600,650,700,and 750μm were selected for mechanical compression experiments on a universal testing machine.(2)The results of mechanical compression experiments showed that with the increase of wall thickness,the elastic modulus and compressive strength of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 550,600,and 650 μm was within the elastic modulus of the mandibular cancellous bone.Finally,the wall thickness of 650 μm and the pore size of 900 μm were selected to construct the three-dimensional model of the mandibular customized Gyroid condylar prosthesis.(3)The results of finite element analysis of three-dimensional model of the mandibular customized Gyroid condylar prosthesis showed that the stress of the articular disc in the edge-to-edge occlusion was mainly concentrated on the lower surface of the anterior middle band,and the stress of the articular disc in the interposition of tooth tips was mainly concentrated on the lateral surface of the lower surface.The maximum displacement and the maximum equivalent stress of the left and right articular discs in the edge-to-edge occlusion and the interposition of tooth tips were similar.The maximum displacement was 0.031,0.030,0.028,and 0.018 mm,and the maximum equivalent stress was 2.87,2.30,2.73,and 1.71 MPa,respectively.(4)The results showed that the Gyroid structure with a wall thickness of 650 μm was consistent with the mechanical properties of the mandible,which reduced the strength of the titanium alloy and reduced the damage of the articular disc caused by the customized Gyroid condylar prosthesis.

BACKGROUND:Condylar prosthesis replacement,as one of the surgical methods for the treatment of temporomandibular joint diseases,not only needs to restore the morphology and function,but also needs to ensure long-term stable application.OBJECTIVE:To design finite element analysis of a customized Gyroid condylar prosthesis.METHODS:Gyroid structure specimens with different wall thicknesses(250,350,450,550,650,and 750 μm)were designed by software.Finite element simulation compression experiments were carried out to test the elastic modulus of the specimens.The Gyroid structure wall thickness range that matches the elastic modulus of mandibular cancellous bone and whose pore size meets the osteogenesis conditions was screened out.This range was subdivided and Gyroid structure specimens were made using 3D printing technology.Mechanical compression experiments were carried out on a universal testing machine.The Gyroid structure wall thickness that meets the mechanical properties of mandibular bone,has an easier osteogenesis and a smaller strength was screened out by elastic modulus and compressive strength,and subsequent experiments were carried out.A three-dimensional model of a customized Gyroid condylar prosthesis was designed,and the finite element analysis of the blade jaw position and cusp interdigitation position of the model under natural occlusion was simulated.RESULTS AND CONCLUSION:(1)Finite element analysis results showed that with the increase of wall thickness,the elastic modulus of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 350,450,550,650,and 750 μm matched the elastic modulus of mandibular cancellous bone.Since the subsequent experiments needed to be subdivided into groups and the pore size of the 550,650,and 750 μm wall thickness group(pore size 800-1 000 μm)was within the osteogenesis range.Gyroid structure specimens with wall thickness of 550,600,650,700,and 750μm were selected for mechanical compression experiments on a universal testing machine.(2)The results of mechanical compression experiments showed that with the increase of wall thickness,the elastic modulus and compressive strength of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 550,600,and 650 μm was within the elastic modulus of the mandibular cancellous bone.Finally,the wall thickness of 650 μm and the pore size of 900 μm were selected to construct the three-dimensional model of the mandibular customized Gyroid condylar prosthesis.(3)The results of finite element analysis of three-dimensional model of the mandibular customized Gyroid condylar prosthesis showed that the stress of the articular disc in the edge-to-edge occlusion was mainly concentrated on the lower surface of the anterior middle band,and the stress of the articular disc in the interposition of tooth tips was mainly concentrated on the lateral surface of the lower surface.The maximum displacement and the maximum equivalent stress of the left and right articular discs in the edge-to-edge occlusion and the interposition of tooth tips were similar.The maximum displacement was 0.031,0.030,0.028,and 0.018 mm,and the maximum equivalent stress was 2.87,2.30,2.73,and 1.71 MPa,respectively.(4)The results showed that the Gyroid structure with a wall thickness of 650 μm was consistent with the mechanical properties of the mandible,which reduced the strength of the titanium alloy and reduced the damage of the articular disc caused by the customized Gyroid condylar prosthesis.

BACKGROUND:Based on the principle of vertical tooth movement,a personalized orthodontic appliance is created through digital design combined with 3D printing,so that the personalized orthodontic appliance forms a support system with the individual incisors.With the help of the absolute support of the micro-implant,the single tooth is precisely controlled in a three-dimensional direction.OBJECTIVE:To design personalized orthodontic appliances with 11,12,21,and 22 intrusion and extrusion based on biomechanical principles,and analyze the safety of the personalized orthodontic appliances in terms of their movement effect on the teeth by means of the three-dimensional finite element method.METHODS:Three-dimensional finite element models of alveolar bone-periodontium-maxillary incisors-personalized cantilever micro-implant-connecting plates-personalized brackets in the maxillary anterior region(teeth numbers 11,12,21,and 22)were established using Mimics,Geomagic Wrap,SolidWorks,and Ansys Workbench software,respectively.Personalized orthodontic appliances with low pressure movement and extended movement were set up at each tooth position.The stress level of each component of the personalized orthodontic appliances was analyzed,and the tooth displacement and periodontal stress distribution were calculated under loading of 300 g tensile or thrust force.RESULTS AND CONCLUSION:(1)The maximum equivalent force on the personalized intrusion mobile orthodontic appliance was 162.90 MPa,and the maximum equivalent force on the personalized extrusion mobile orthodontic appliance was 239.57 MPa.The maximum equivalent stress on both devices was located in the vertical portion of the personalized bracket loading attachment.The equivalent stresses on each part of the personalized orthodontic appliance were all within the yield strength,and they had good safety.(2)The initial displacement of the teeth under the action of the personalized orthodontic appliances showed a tendency towards overall intrusion or extrusion,with the displacement in the vertical direction far exceeding that in the horizontal and sagittal directions.The equivalent stress peak appeared at the root tip or neck of the periodontal membrane,and the equivalent stress concentration area appeared in the periodontal membrane of the root apical region.(3)The results show that the personalized orthodontic appliance allows 11,12,21,and 22 to approximate either intrusion movement or extrusion movement,initially confirming the effectiveness of the personalized vertical movement orthodontic appliance.

BACKGROUND:Currently,the mandibular joint prosthesis manufactured at home and abroad needs to rely on screws to fix the condylar part of the prosthesis during the replacement process,and the retention hole is reserved to facilitate the operation during the operation.However,due to the lack of personalized jaw design,the reattachment plate may not fit the jaw,resulting in screw loosening and dislocation.Therefore,personalized condylar prosthesis replacement is of great value in the repair of the temporomandibular joint.OBJECTIVE:To design a personalized condylar prosthesis with an internal GYROID for mandibular condylar repair and reconstruction.METHODS:The GYROID structure was selected in the Rhinoceros 7 software with the single cell size of 6 mm and the wall thickness of 0.2,0.3,0.4,0.5,0.6,0.7,0.8 mm.The mechanical properties of the GYROID structure were analyzed by finite element method.3D printing of GYROID structural test specimens with different wall thickness(0.2,0.3,0.4,0.5,0.6,0.7,and 0.8 mm)was performed to test the mechanical properties of the specimens through room temperature compression experiments.A wall thickness value conforming to the range of mandibular mechanical properties was selected through finite element analysis and room temperature compression test results.An adult male mandibular CT data were used for inverse modeling to design a condylar prosthesis with an internal GYROID.Finite element analysis was used to simulate the movement of the apical staggered position and the opposite-blade jaw position after condylar prosthesis replacement.RESULTS AND CONCLUSION:(1)The results of finite element analysis and room temperature compression experiment showed that the elastic modulus of the GYROID structure increased with the increase of wall thickness.The elastic modulus of the GYROID structure with wall thickness of 0.5-0.7 mm was within the range of the elastic modulus of the mandible(1.5-4.0 GPa).Therefore,the 6 mm monocellular GYROID structural model with a wall thickness of 0.6 mm was selected for the design of the condylar prosthesis.(2)The results of finite element analysis showed that the stress distribution of mandibular model was symmetrical.The stress distribution of the two types of occlusion was roughly the same,and the stress peak was not significantly different.The stress concentrated in the neck of the condylar prosthesis,and the stress on the replacement side was slightly larger than that on the healthy side.The maximum equivalent stress of the whole internal fixation model was 269.34 MPa,and the maximum equivalent stress of the screw was 20.14 MPa.The equivalent stress and equivalent strain values of the prosthesis were greater than that of the opposite edge jaw position when the tooth tip was interlaced.The equivalent stress and equivalent strain values of the screw were smaller than that of the opposite edge jaw position when the tooth tip was interlaced.(3)The results showed that the design and retention of the personalized GYROID condylar prosthesis were good,which was consistent with the mechanical conduction of the mandible.

BACKGROUND:Porous structures based on triple periodic minimal surfaces are one of the most promising orthopedic biostructures,among which the Gyroid structure is characterized by high specific surface area,high permeability,and zero mean curvature.OBJECTIVE:To screen the wall thickness interval of TC4 bionic bone scaffolds with 4 mm single-cell Gyroid structure matching the elastic modulus range of cancellous bone of the mandible through finite element analysis combined with mechanical compression test testing.METHODS:The finite element model of the 4 mm single-cell Gyroid structure with different wall thickths(0.1,0.2,0.3,0.4,0.5,0.6,0.7,and 0.8 mm)was established.The equivalent elastic modulus of the Gyroid structure was analyzed,and the wall thickness interval of the Gyroid structure matching the elastic modulus range of the maxillary resinous bone was selected with different wall thicknesses of 0.2,0.3,0.4,0.5,0.6,and 0.7 mm,respectively.According to finite element analysis screening results,the material selected was Ti6Al4V.Selective laser melting was used to prepare 3D printed Gyroid structure specimens.The surface treatment was carried out by large-grained sand blasting and acid etching.The elastic modulus and compressive strength of the specimen were tested by mechanical compression experiment.RESULTS AND CONCLUSION:(1)The finite element analysis results showed that the equivalent elastic modulus of the Gyroid structure increased with the increase of wall thickness,and the equivalent elastic modulus of the Gyroid structure with wall thickness of 0.2-0.7 mm was within the range of the elastic modulus of the spongy bone of the mandible(1.5-4.0 GPa),which was used for 3D printing of the Gyroid structure specimen.(2)The mechanical compression test results showed that the elastic modulus and compressive strength of the Gyroid structural specimen increased with the increase of wall thickness,and the elastic modulus of the Gyroid structural specimen with wall thickness of 0.3-0.5 mm was within the range of the elastic modulus of the cancellous bone of the mandible.The compressive strength of the Gyroid specimen with 0.3-0.7 mm wall thickness was consistent with the mechanical properties of the mandible.(3)The results show that the Gyroid structure of 0.3-0.5 mm wall thickness is compatible with the range of elastic modulus of the mandible.

OBJECTIVE To ex plore the economic value of medication therapeutical management （MTM）service for patients with stable coronary disease. METHODS Totally 140 patients with stable coronary disease were divided into a control group and a intervention group ，70 cases in each group. Patients in control group were received routine medical services ，and patients in intervention group additionally received standardized MTM services on this basis. Medication complication ，satisfaction degree ， safety indexes and efficacy indexes were compared between 2 groups. From the perspective of the whole society ，the economic value of MTM service for patients with stable coronary disease were evaluated by pharmacists using cost minimization analysis. RESULTS A total of 15 patients did not complete the study ，including 5 cases in intervention group and 10 cases in control group ； there was no death endpoint during the follow-up period. MMAS- 8 score，satisfaction score of drug communication dimension and score of overall satisfactionin of intervention group were obviously higher than control group （P＜0.01）. There was no significant difference in blood pressure standard rate ，blood lipid standard rate ，the incidence of adverse drug reaction ，and the incidence of acute coronary events between 2 groups（P＞0.05）. The total cost of intervention group was lower than that of control group （P＜ 0.01）；the results of sensitivity analysis were consistent with those of cost minimization analysis. CONCLUSIONS Pharmacists implement MTM service for patients with stable coronary disease can reduce total cost ，save medical resources and has economic advantages.

Poststroke cognitive impairment includes poststroke non-dementia cognitive impairment and poststroke dementia, which is a cognitive dysfunction caused by the vascular factors, neural degeneration or mixed factors. Although the concept of poststroke cognitive impairment has not been generally accepted, it is worth further investigation, This article introduces the epidemiology, risk factors, pathogenesis, clinical manifestation, and prevention and treatment measures of poststroke cognitive impairment.