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A further finite element stress analysis of angled abutments for an implant placed in the anterior maxilla.

Wu D, Tian K, Chen J, Jin H, Huang W, Liu Y - Comput Math Methods Med (2015)

Bottom Line: Response curves under oblique loading were similar in both models.With abutments angulation increased, maximum von Mises stress firstly decreased to minimum point and then gradually increased to higher level.From a biomechanical point of view, favorable peri-implant stress levels could be induced by angled abutments under oblique loading if suitable angulation of abutments was selected.

View Article: PubMed Central - PubMed

Affiliation: School of Stomatology, Fujian Medical University, Fuzhou, Fujian 350000, China ; Department of Oral Implantology, Affiliated Stomatological Hospital of Fujian Medical University, Fuzhou, Fujian 350002, China.

ABSTRACT
To systematically measure and compare the stress distribution on the bone around an implant in the anterior maxilla using angled abutments by means of finite element analysis, three-dimensional finite element simplified patient-specific models and simplified models were created and analyzed. Systematically varied angled abutments were simulated, with angulation ranging from 0° to 60°. The materials in the current study were assumed to be homogenous, linearly elastic, and isotropic. Force of 100 N was applied to the central node on the top surface of the abutments to simulate the occlusal force. To simulate axial and oblique loading, the angle of loading was 0°, 15°, and 20° to the long axis of implant, respectively. There was the strong resemblance between the response curves for simplified patient-specific models and simplified models. Response curves under oblique loading were similar in both models. With abutments angulation increased, maximum von Mises stress firstly decreased to minimum point and then gradually increased to higher level. From a biomechanical point of view, favorable peri-implant stress levels could be induced by angled abutments under oblique loading if suitable angulation of abutments was selected.

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Related in: MedlinePlus

Simplified patient-specific models: A cone-beam computerized tomography scan projection of a maxillary central incisor region was obtained (a), the outline of the image was manually converted (b). Simplified patient-specific models were created by extruding the simplified cross-sectional image (c). Simplified models were used in this study (d). The geometry of the implant-abutment complex was developed based on the models described in the previous study;  α was abutment angulation (e). All models were combined by Boolean operations (f, g). (h) F: occlusal force;  β (loading angle) = 0°, 15°, and 20°. (i, j) Meshed implants and bone.
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fig1: Simplified patient-specific models: A cone-beam computerized tomography scan projection of a maxillary central incisor region was obtained (a), the outline of the image was manually converted (b). Simplified patient-specific models were created by extruding the simplified cross-sectional image (c). Simplified models were used in this study (d). The geometry of the implant-abutment complex was developed based on the models described in the previous study;  α was abutment angulation (e). All models were combined by Boolean operations (f, g). (h) F: occlusal force;  β (loading angle) = 0°, 15°, and 20°. (i, j) Meshed implants and bone.

Mentions: For the present study, two different three-dimensional finite element models are as follows. Simplified patient-specific models and simplified models were created and analyzed using ANSYS 9.0 software (ANSYS, Canonsburg, PA). Simplified patient-specific models are as follows. A cone-beam computerized tomography scan projection of a maxillary central incisor region (Figure 1(a)) was obtained from the Department of Oral and Maxillofacial Radiology, Affiliated Stomatological Hospital of Fujian Medical University. To simplify analysis, the outline of the image was manually converted and palatine segment was cut off (Figure 1(b)). The simplified cross-sectional image was then extruded to create an anterior maxilla segment. The dimensions of the anterior maxilla segment are shown in Figure 1(c). The overall dimensions of the bone model were 20 mm in vertical height, 20 mm in mesiodistal length, and 9 mm in labiopalatal width at the ridge crest. The average thickness of the cortical bone in the crestal region was 1.5 mm. The mesial and distal planes were not covered by cortical bone. The simplified models (Figure 1(d)) were approximately 9 mm in width buccolingually and 20 mm in height coronoapically and 20 mm in length mesiodistally. The simplified models consisted of two layers: a cortical layer and a cancellous layer. The cortical bone was modeled as a 1.5 mm layer on the facial, lingual, and occlusal aspects of the bone wedge. The geometry of the implant-abutments complex (Figure 1(e)) was developed based on the models described in the previous study [13]. A modification was made such that the abutments angulation was a variable factor. The angulations of abutments were adopted from the commonly used angled abutments available from the relevant literature [1, 2, 5, 17]. Systematically varied angled abutments were simulated, with angulation ranging from 0° to 60°. All models were combined by Boolean operations (Figures 1(f) and 1(g)). All of the materials in the current study were assumed to be homogenous, linearly elastic and isotropic to simplify computation processes. The mechanical properties (Table 2), boundary conditions, and the nature of loading were obtained from relevant studies [2, 13]. Occlusal forces are typically 100 N under normal biting, with higher forces occurring in patients suffering from bruxism or parafunction. Force of 100 N was applied to the central node on the top surface of the abutments to simulate the occlusal force [13, 18]. Axial and oblique loading were applied to each model. The angle of oblique loading was 15° and 20° to the long axis of implant (Figure 1(h)), because most occlusal loads applied to anterior teeth were at an angled to the long axis the implant [12]. Direction of axial loading was parallel to the long axis of implant; the angle of loading was 0° to the long axis of implant. The interface between the cortical and cancellous bone layers and between the implant and each of the bone layers was assumed to be properly bonded to correspond with good osseointegration. The lower surface of the model and the medial and distal planes of bone were completely constrained [17]. The numerical models were meshed with 1.0 mm of element sizing (Figures 1(i) and 1(j)). For angled abutments, dental implants, cortical bone, and trabecular bone, a 10-node solid element of SOLID 187 was used. Meshed simplified patient-specific models showed a number of nodes ranging 87,236 to 87,844 and number of elements ranging from 53,069 to 53866 (Figure 1(i)). Simplified models were composed of 39,000 nodes and 16,000 elements with a small difference in various models (Figure 1(j)). The maximum von Mises stress for cortical and cancellous bone was recorded. Abutments angulation was set as the input variables. The maximum von Mises stress was set as output variables to evaluate the effect of different abutments angulation on the jaw bone and implant. The response curves of input variables to output variables were constructed.


A further finite element stress analysis of angled abutments for an implant placed in the anterior maxilla.

Wu D, Tian K, Chen J, Jin H, Huang W, Liu Y - Comput Math Methods Med (2015)

Simplified patient-specific models: A cone-beam computerized tomography scan projection of a maxillary central incisor region was obtained (a), the outline of the image was manually converted (b). Simplified patient-specific models were created by extruding the simplified cross-sectional image (c). Simplified models were used in this study (d). The geometry of the implant-abutment complex was developed based on the models described in the previous study;  α was abutment angulation (e). All models were combined by Boolean operations (f, g). (h) F: occlusal force;  β (loading angle) = 0°, 15°, and 20°. (i, j) Meshed implants and bone.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4352728&req=5

fig1: Simplified patient-specific models: A cone-beam computerized tomography scan projection of a maxillary central incisor region was obtained (a), the outline of the image was manually converted (b). Simplified patient-specific models were created by extruding the simplified cross-sectional image (c). Simplified models were used in this study (d). The geometry of the implant-abutment complex was developed based on the models described in the previous study;  α was abutment angulation (e). All models were combined by Boolean operations (f, g). (h) F: occlusal force;  β (loading angle) = 0°, 15°, and 20°. (i, j) Meshed implants and bone.
Mentions: For the present study, two different three-dimensional finite element models are as follows. Simplified patient-specific models and simplified models were created and analyzed using ANSYS 9.0 software (ANSYS, Canonsburg, PA). Simplified patient-specific models are as follows. A cone-beam computerized tomography scan projection of a maxillary central incisor region (Figure 1(a)) was obtained from the Department of Oral and Maxillofacial Radiology, Affiliated Stomatological Hospital of Fujian Medical University. To simplify analysis, the outline of the image was manually converted and palatine segment was cut off (Figure 1(b)). The simplified cross-sectional image was then extruded to create an anterior maxilla segment. The dimensions of the anterior maxilla segment are shown in Figure 1(c). The overall dimensions of the bone model were 20 mm in vertical height, 20 mm in mesiodistal length, and 9 mm in labiopalatal width at the ridge crest. The average thickness of the cortical bone in the crestal region was 1.5 mm. The mesial and distal planes were not covered by cortical bone. The simplified models (Figure 1(d)) were approximately 9 mm in width buccolingually and 20 mm in height coronoapically and 20 mm in length mesiodistally. The simplified models consisted of two layers: a cortical layer and a cancellous layer. The cortical bone was modeled as a 1.5 mm layer on the facial, lingual, and occlusal aspects of the bone wedge. The geometry of the implant-abutments complex (Figure 1(e)) was developed based on the models described in the previous study [13]. A modification was made such that the abutments angulation was a variable factor. The angulations of abutments were adopted from the commonly used angled abutments available from the relevant literature [1, 2, 5, 17]. Systematically varied angled abutments were simulated, with angulation ranging from 0° to 60°. All models were combined by Boolean operations (Figures 1(f) and 1(g)). All of the materials in the current study were assumed to be homogenous, linearly elastic and isotropic to simplify computation processes. The mechanical properties (Table 2), boundary conditions, and the nature of loading were obtained from relevant studies [2, 13]. Occlusal forces are typically 100 N under normal biting, with higher forces occurring in patients suffering from bruxism or parafunction. Force of 100 N was applied to the central node on the top surface of the abutments to simulate the occlusal force [13, 18]. Axial and oblique loading were applied to each model. The angle of oblique loading was 15° and 20° to the long axis of implant (Figure 1(h)), because most occlusal loads applied to anterior teeth were at an angled to the long axis the implant [12]. Direction of axial loading was parallel to the long axis of implant; the angle of loading was 0° to the long axis of implant. The interface between the cortical and cancellous bone layers and between the implant and each of the bone layers was assumed to be properly bonded to correspond with good osseointegration. The lower surface of the model and the medial and distal planes of bone were completely constrained [17]. The numerical models were meshed with 1.0 mm of element sizing (Figures 1(i) and 1(j)). For angled abutments, dental implants, cortical bone, and trabecular bone, a 10-node solid element of SOLID 187 was used. Meshed simplified patient-specific models showed a number of nodes ranging 87,236 to 87,844 and number of elements ranging from 53,069 to 53866 (Figure 1(i)). Simplified models were composed of 39,000 nodes and 16,000 elements with a small difference in various models (Figure 1(j)). The maximum von Mises stress for cortical and cancellous bone was recorded. Abutments angulation was set as the input variables. The maximum von Mises stress was set as output variables to evaluate the effect of different abutments angulation on the jaw bone and implant. The response curves of input variables to output variables were constructed.

Bottom Line: Response curves under oblique loading were similar in both models.With abutments angulation increased, maximum von Mises stress firstly decreased to minimum point and then gradually increased to higher level.From a biomechanical point of view, favorable peri-implant stress levels could be induced by angled abutments under oblique loading if suitable angulation of abutments was selected.

View Article: PubMed Central - PubMed

Affiliation: School of Stomatology, Fujian Medical University, Fuzhou, Fujian 350000, China ; Department of Oral Implantology, Affiliated Stomatological Hospital of Fujian Medical University, Fuzhou, Fujian 350002, China.

ABSTRACT
To systematically measure and compare the stress distribution on the bone around an implant in the anterior maxilla using angled abutments by means of finite element analysis, three-dimensional finite element simplified patient-specific models and simplified models were created and analyzed. Systematically varied angled abutments were simulated, with angulation ranging from 0° to 60°. The materials in the current study were assumed to be homogenous, linearly elastic, and isotropic. Force of 100 N was applied to the central node on the top surface of the abutments to simulate the occlusal force. To simulate axial and oblique loading, the angle of loading was 0°, 15°, and 20° to the long axis of implant, respectively. There was the strong resemblance between the response curves for simplified patient-specific models and simplified models. Response curves under oblique loading were similar in both models. With abutments angulation increased, maximum von Mises stress firstly decreased to minimum point and then gradually increased to higher level. From a biomechanical point of view, favorable peri-implant stress levels could be induced by angled abutments under oblique loading if suitable angulation of abutments was selected.

Show MeSH
Related in: MedlinePlus