| Resin Bonded Fixed Partial Denture is a type of restoration which need little clearance and bring much less invasion to the natural teeth, and in line with the concept of minimally invasive therapy of the new century. With the development of material science, RBFPD has gained much attention and clinical applications as well. It has become the 3rd choice after the conventional FPB and implant in restoring single teeth defecation.According to the prosthetic design, RBPFDs can be divided into single-ended and double-ended. Meanwhile, they can be divided into 2 categories: metals and non-metal, according to the materials out of which they are fabricated. With the outstanding physical and optical property, Zirconia RBFPD has become the focus of modern RBFPD researches. Especially, although the Zirconia RBFPD in the anterior region has been widely and successfully used for decades, the systematic and quantitative biomechanical study of such prosthesis is still rare.1 research purposesThe experimental design single-ended and double-side front teeth bonded zirconia ceramic fixed bridge using the finite element method to study the restoration, abutment teeth, periodontal membrane, alveolar bone, adhesive layer displacement, stress and distribution of clinical choose the best fix for the delivery of bio-mechanics theory of reference.2 Research MethodsWe chose the left maxillary lateral incisor missing, were single-side adhesive bridge |①2, | 2③and double-end bond bridge |①2③three types of repair design. Zirconia all-ceramic materials (Y-TZP) made resin-bonded fixed partial denture, select the Panavia F resin cement (Coke Franc Japanese-style club) bond. Using three-dimensional finite element method to study the restoration, abutment teeth, periodontal membrane, alveolar bone, adhesive layer displacement and stress distribution. 2.1 According to the basic principles of finite element method model:2.1.1 Modeling of materials: choose a dentition is complete and meets standards of normal occlusion, periodontal health, oral disease without any adult female volunteers as subjects, line three-dimensional spiral CT scanning.2.1.2 Experimental equipment: 64-slice spiral CT machine (Brilliance 64 Slice CT System-EWB, Philips), graphic image software Auto CAD2007, reverse engineering software Geomagic9.0, finite element pre-processing software Icemefd11.0, three-dimensional finite element analysis software Abaqus6.8.2.1.3 maxillary 1 | 1234 teeth and supporting tissues of the three-dimensional segment models: including the image data acquisition and processing; teeth, the jaw model; periodontal tissue model (Zhou film thickness of 0.2mm).2.1.4 Three-dimensional bonding bridge restoration model: application Abaqus6.8 software simulation | 2 defects in alveolar bone integrity, reverse build and repair body adhesive layer finite element.Bonded bridge retainer type: retainer tongue flanking panels, thickness: 0.8mm. Range: from the gingival margin, far short gap side abutment ridge, cut ends of the 1mm. Some recent short gap around the proximal side.2.2 Finite Element Analysis2.2.1 Conditions set: first tooth, periodontal membrane, alveolar bone, bonded bridges, adhesives and other materials were given different mechanical parameters are assumed to be continuous homogeneous, continuous and isotropic line elastic material, the force generated when the models are not mutually sliding the cross section, between the various units have adequate stability, material deformation of small deformation, a non-rigid boundary around the alveolar bone. 2.2.2 Conditions set: means of static load, according to our normal young women are several occlusal loading [55], load force: 100N. Condition 1: vertical load, position: bridge cutting edge area; directions: parallel with the axis of the tooth. Condition 2: oblique load, position: lateral tongue bridge in 1 / 3 junction; direction: the axis of the tooth showed a clip angle 45°.2.2.3 Calculation and Analysis: The calculation includes①prosthesis (zirconia),②abutment,③periodontal ligament,④alveolar bone, the stress and displacement,⑤adhesive layer shear stress.Software to calculate the output node with Abaqus6.8 the displacement and stress, in order to facilitate the analysis, were taken VonMises stress, then stress concentration zone, the maximum displacement, the displacement direction were compared, statistical calculations and analysis. And draw the stress and displacement distribution.3 Results3.1 The restoration of the stress and displacement situation: three kinds of stress distribution and displacement of the design's overall trend. Connectors is the stress concentration region, where the edge of extreme value for the stress, the stress from the flange connection to the far lateral side of the missing gap decreased. Single-ended bond oblique load, the bridge is greater than the vertical stress and displacement load, while the double-side adhesive bridge in value slightly decreased when the vertical load. Displacement change is the maximum value of bridge loading area, and gradually decreased to the flange.3.2 abutment stress and displacement: The stress concentration near missing gap in the Guanzhong area proximal 1 / 3 to 1 / 3 neck, extension of the long axis of teeth on both sides gradually reduced. Single-ended bond bridge oblique load stress than the vertical load increases, double-side adhesive bridge slightly oblique load, lower than the vertical load. Displacement to the gum from the cut end to the decreased value of single-ended oblique loading large, double-end value of a large vertical load. Abutments | 3, the stress and displacement, with the single-ended bond bridge | 2③abutment | 3 difference is not obvious. Single-ended bond bridge | 2③the stress concentration zones of small and uniform, and the apical displacement of the stress value and the minimum. See Table 3 3.3 periodontal ligament of the stress and displacement: The results showed that extreme stress and oblique loads were greater than the vertical displacement of extreme load and stress concentration in the range of oblique loads have increased. Stress concentration zone in the cervical periodontal membrane edge area is greater than the outer surface of the inner surface of the stress from the neck edge down gradually reduced, the root is relatively stable middle, apical 1 / 3 of the previous paragraph is slightly elevated, but then decreased, apical hole in the stress of the minimum value.Bonded abutment | 3 min minimum stress on root tips, followed by |①2 bonded abutment | 1 of the root tip, again |①2③bonded abutment | 1 of the root tip, and the maximum |①2③bonded abutment | 3 of the biggest tip. Displacement as follows: from the neck to the apical margin gradually decreases on both sides of the periodontal ligament adjacent teeth are slightly deformed. See Table 4 3.4 alveolar bone stress and displacement: The data come close to missing the stress concentration area for the neck at the edge of gap area to the apical decreased stress concentration labial alveolar bone. Oblique load, extreme stress and extreme value is greater than the vertical displacement of load, deformation and stress concentration areas and bigger. Single-ended bond bridge |①2 in the two loads have on the abutment teeth | 1 far side of the edentulous ridge (ie, | 1 near middle) of the alveolar bone has obvious stress concentration, but in | 2③Bonded bridge, there is no stress concentration in the base tooth | 3 far side of the edentulous ridge (ie | 3 distal) of the alveolar bone. Double-bonded bridge on adjacent teeth (ie, 1 | 4) impact, expressed in 1 | the tongue side of the neck and | 4 lip lateral neck, also suggesting the torque. The displacement of alveolar bone at the edge of a neck to tip direction is gradually reduced, minor differences in three designs. See Table 5 3.5 adhesive layer shear stress shift: The adhesive layer shear stress concentration zone near edentulous area adjacent side of the body and the flange connecting joints, gradually decreased and turned axis plane angle, the basic maintenance of uniform. Discussed here mean the overall bonding layer for analysis. See Table 64 Conclusion1. Double-bonded bridges bonded bridge design is superior to single-ended design, stress distribution more reasonable. Single-ended bond bridge | 2③design is better than |①2.2. Single-ended bond bridge | 2③supporting tissues of the roots the least.3. Adhesive: Double-bonded bridge |①2③conducive adhesive layer stress di stribution, but obviously there is torque, and single-ended bond bridge | 2③obvious difference. Single-ended bond bridge | 2③than single-ended bond bridge |①2 stress distribution is reasonable.
|
PDF Full Text Request