Titanium tube and stainless steel tube plate were welded by an innovative friction welding of tube to tube plate using an external tool (FWTPET). Copper was used as an interlayer for joining the dissimilar materials a...Titanium tube and stainless steel tube plate were welded by an innovative friction welding of tube to tube plate using an external tool (FWTPET). Copper was used as an interlayer for joining the dissimilar materials and also to minimize the effect of intermetallics formed at the joint interface. The process parameters that govern FWTPET process are plunge rate, rotational speed, plunge depth, axial load and flash trap profile. Among them, the flash trap profile of the tube has a significant influence on the joint integrity. Various flash trap profiles like vertical slots, holes, zig-zag holes, and petals were made on the titanium tube welded to the stainless steel tube plate. Macroscopic and microscopic studies reveal defect-free joints. The presence of copper interlayer and intermetallics was evident from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) studies. The microhardness survey was presented across and along the interface. A novel test procedure called “plunge shear test” was developed to evaluate the joint properties of the welded joints. The highest shear fracture load of 31.58 kN was observed on the sample having petals as flash trap profile. The sheared surfaces were further characterized using SEM for fractography.展开更多
Objective:The purpose of this study was to evaluate three-dimensional(3D) dehiscence of upper anterior alveolar bone during incisor retraction and intrusion in adult patients with maximum anchorage.Methods:Twenty adul...Objective:The purpose of this study was to evaluate three-dimensional(3D) dehiscence of upper anterior alveolar bone during incisor retraction and intrusion in adult patients with maximum anchorage.Methods:Twenty adult patients with bimaxillary dentoalveolar protrusion had the four first premolars extracted.Miniscrews were placed to provide maximum anchorage for upper incisor retraction and intrusion.A computed tomography(CT) scan was performed after placement of the miniscrews and treatment.The 3D reconstructions of pre-and post-CT data were used to assess the dehiscence of upper anterior alveolar bone.Results:The amounts of upper incisor retraction at the edge and apex were(7.64±1.68) and(3.91±2.10) mm,respectively,and(1.34±0.74) mm of upper central incisor intrusion.Upper alveolar bone height losses at labial alveolar ridge crest(LAC) and palatal alveolar ridge crest(PAC) were 0.543 and 2.612 mm,respectively,and the percentages were(6.49±3.54)% and(27.42±9.77)%,respectively.The shape deformations of LAC-labial cortex bending point(LBP) and PAC-palatal cortex bending point(PBP) were(15.37±5.20)° and(6.43±3.27)°,respectively.Conclusions:Thus,for adult patients with bimaxillary protrusion,mechanobiological response of anterior alveolus should be taken into account during incisor retraction and intrusion.Pursuit of maximum anchorage might lead to upper anterior alveolar bone loss.展开更多
基金financial support provided by UGC-DAE-CSR (CSR-KN/CRS-04/201213/738) through fellowship
文摘Titanium tube and stainless steel tube plate were welded by an innovative friction welding of tube to tube plate using an external tool (FWTPET). Copper was used as an interlayer for joining the dissimilar materials and also to minimize the effect of intermetallics formed at the joint interface. The process parameters that govern FWTPET process are plunge rate, rotational speed, plunge depth, axial load and flash trap profile. Among them, the flash trap profile of the tube has a significant influence on the joint integrity. Various flash trap profiles like vertical slots, holes, zig-zag holes, and petals were made on the titanium tube welded to the stainless steel tube plate. Macroscopic and microscopic studies reveal defect-free joints. The presence of copper interlayer and intermetallics was evident from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) studies. The microhardness survey was presented across and along the interface. A novel test procedure called “plunge shear test” was developed to evaluate the joint properties of the welded joints. The highest shear fracture load of 31.58 kN was observed on the sample having petals as flash trap profile. The sheared surfaces were further characterized using SEM for fractography.
基金Project supported by the Shandong Science and Technology Planning Project Contract Research (Nos. 2008GG30002019 and 2008GG 30001001) of Chinathe Shandong University Dental School Project Research (Nos. P2009009,P2009010,and P2010010),China
文摘Objective:The purpose of this study was to evaluate three-dimensional(3D) dehiscence of upper anterior alveolar bone during incisor retraction and intrusion in adult patients with maximum anchorage.Methods:Twenty adult patients with bimaxillary dentoalveolar protrusion had the four first premolars extracted.Miniscrews were placed to provide maximum anchorage for upper incisor retraction and intrusion.A computed tomography(CT) scan was performed after placement of the miniscrews and treatment.The 3D reconstructions of pre-and post-CT data were used to assess the dehiscence of upper anterior alveolar bone.Results:The amounts of upper incisor retraction at the edge and apex were(7.64±1.68) and(3.91±2.10) mm,respectively,and(1.34±0.74) mm of upper central incisor intrusion.Upper alveolar bone height losses at labial alveolar ridge crest(LAC) and palatal alveolar ridge crest(PAC) were 0.543 and 2.612 mm,respectively,and the percentages were(6.49±3.54)% and(27.42±9.77)%,respectively.The shape deformations of LAC-labial cortex bending point(LBP) and PAC-palatal cortex bending point(PBP) were(15.37±5.20)° and(6.43±3.27)°,respectively.Conclusions:Thus,for adult patients with bimaxillary protrusion,mechanobiological response of anterior alveolus should be taken into account during incisor retraction and intrusion.Pursuit of maximum anchorage might lead to upper anterior alveolar bone loss.
