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Table of Contents   
ORIGINAL RESEARCH  
Year : 2013  |  Volume : 24  |  Issue : 4  |  Page : 423-427
Finite element stress analysis on the influence of cuspal angle and superstructure materials in an implant-supported prosthesis


1 Department of Prosthodontics, Meenakshi Ammal Dental College and Hospital, Vanagaram, Chennai, Tamilnadu, India
2 Department of Prosthodontics, SRM Dental College, Ramapuram, Chennai, Tamilnadu, India

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Date of Submission10-Jan-2013
Date of Decision29-Jan-2013
Date of Acceptance11-Mar-2013
Date of Web Publication19-Sep-2013
 

   Abstract 

Purpose: To investigate the effect of superstructure materials and cuspal angle in an implant-supported fixed partial denture.
Materials and Methods: This finite element analysis study was carried out with varying cuspal angulations of 0°, 20° and 33° and superstructure materials. The simulated models were loaded with 300N forces under different axial and non-axial angulations. The graphical and numerical stresses were investigated.
Results: The results demonstrated that the maximum stress occurred in the metal framework in all the materials except acrylic, for which it occurred in the coronal part of the implant. In the acrylic, the maximum stress recorded was 78 MPa with the 20° angulation. Ni Cr recorded a maximum stress of 111 MPa with the 33° angulation.
Conclusion: The cuspal morphology and type of superstructure material plays a pivotal role in controlling the stress transferred to the implant and the supporting bone.

Keywords: Cuspal angle, finite element analysis, implant prosthesis material

How to cite this article:
Lambodaran G, Chander N G, Vasantakumar M. Finite element stress analysis on the influence of cuspal angle and superstructure materials in an implant-supported prosthesis. Indian J Dent Res 2013;24:423-7

How to cite this URL:
Lambodaran G, Chander N G, Vasantakumar M. Finite element stress analysis on the influence of cuspal angle and superstructure materials in an implant-supported prosthesis. Indian J Dent Res [serial online] 2013 [cited 2019 Nov 14];24:423-7. Available from: http://www.ijdr.in/text.asp?2013/24/4/423/118384
The success of implant-supported prosthesis is influenced by many factors. The material of the superstructure, design of the fixture, cantilever length, mechanism of bone implant interface and occlusion play a significant role. [1] Among these factors, occlusal loading of implants plays a major part in the long-term success of an implant treatment. [2] Lindquist et al.[3] and Weinberg and Kruger [4] affirmed the role of occlusion in controlling the stress concentration on an implant-supported prosthesis.

The selection of an optimal occlusal surface material for implant-supported prosthesis showed varied results. Skalak [1] and Holst et al.[5] demonstrated that the resiliency of acrylic resin can act against overstress and microfracture of the bone-implant interface. Davis and Rimrott [6] reported that porcelain reduced the stress in the bone-implant interface under static loading. Sergotz et al.[7] revealed that the cobalt-chromium framework and the porcelain occlusal surface was the most favorable combination for implant-supported restoration. Bassit [8] and Cibirka et al.[9] confirmed that different occlusal surface materials do not produce diverse stresses on implants. This study was initiated to examine the hypothesis that different superstructure materials might affect stress transmission on implant and supporting bone under functional forces.


   Materials and Methods Top


A 3D finite element model of Misch [10] D2 mandibular bone with 24.2 mm height and 40 mm width with missing second premolar, first molar, second molar and its superstructures were replicated in this study. A single-stage, cylindrical, threaded 4.1 mm × 13 mm dental implant system for the second premolar region and 4.1 mm × 13 mm for the second molar region were modeled for this study. The implant and its superstructure with cuspal angulations of 0°, 20° and 33° were simulated using the finite-element (Pro/Engineer 2000i) software [Figure 1], [Figure 2] and [Figure 3]. Five different superstructure materials used for analysis were heat-polymerized acrylic (Sample A), gold porcelain crown design (Sample B), base metal (Ni Cr) crown design (Sample C), porcelain-fused base metal (Ni Cr) crown design (PFBM) (Sample D) and in-Ceram porcelain crown design (Sample E). Porcelain and metal thicknesses used in this study were 0.8-2 mm. Luting cement space was ignored due to negligible properties in FEM. All materials used were considered to be linear, elastic, homogeneous and isotropic. The average of the mechanical properties, such as Youngs modulus and Poisons ratio, were considered for the study and are listed in [Table 1]. [10],[11] Bone-implant contact and implant abutment junctions were rigidly connected to replicate osseointegration. Fifty thousand three hundred and twenty-seven elements and 91770 nodes were created, and the models were constrained in all directions at the nodes. A vertical force of 300 N was applied on three points: 100 N on the buccal cusp, 100 N on the mesial fossa and 100 N on the distal fossae [Figure 4]. Static forces were applied and Von Mises stress was documented. Stress values were appraised for each type of material for the three different cuspal angulations. The highest stress value obtained from the models was visualized and recorded.
Table 1: Material properties ascribed in the models[10,11]

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Figure 1: 0° degree cuspal angulation model

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Figure 2: 20° degree cuspal angulation model

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Figure 3: 33° degree cuspal angulation model

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Figure 4: Three-point loading of model

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   Results Top


The observed stress values are listed in [Table 2]. The interpretation of the analysis showed that the maximum stresses occurred at the cervical region of all the superstructure materials, irrespective of the cuspal angulations, except for Sample A, where it occurred in the coronal part of the implant. Sample A superstructure had the maximum stress of 111.2 Mpa for the 33° cuspal angulations [Figure 5]. The maximum stress values recorded for Samples B, C, D and E were 140.45 Mpa, 198.3 Mpa, 183.04 Mpa and 157.87 Mpa, respectively [Figure 6], [Figure 7], [Figure 8] and [Figure 9].
Table 2: Stress values observed for different angulations and occlusal materials in implant - supported prosthesis

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Figure 5: Maximum Von Misses stress in acrylic

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Figure 6: Maximum Von Misses stress in gold porcelain

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Figure 7: Maximum Von Misses stress in Ni Cr

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Figure 8: Maximum Von Misses stress in Ni Cr porcelain

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Figure 9: Maximum Von Misses stress in all porcelain

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   Discussion Top


Biomechanical considerations were recognized as the most important factors for the long-term success of implant-supported restorations. [11],[12],[13] Ciftci, [14] and Gracy et al.[15] stressed the importance of the occlusal considerations on implant restorations. The significance of occlusal materials and cuspal angle were evaluated in this study with the objective of examining the hypothesis that different superstructure materials may affect the stress transmission on an implant-supported fixed partial denture.

The finite element method was used in this study because of its superiority in computer programming methods, computational power and digital imaging technique. [16] The posterior mandibular region (35, 36, 37) was simulated in this finite element analysis study because occlusal forces are more concentrated in this region and, being a load-bearing region, more stress can be anticipated in this partially edentulous region. [17] The Noble replace tapered groove of regular platform was used to have a more standardized study protocol. A force of 300 N was applied at the centric stop points [18] and the stresses were evaluated for different cuspal angulations of 0, 20 and33 degrees and different superstructure materials. For effective evaluation, the stresses were analyzed in the various positions of bone, implant and superstructure (occlusal surface, framework, connector), and the highest stress value observed in the model was documented.

The results showed that the maximum stresses were recorded on the framework in all the materials except for acrylic, in which it was recorded on the implant. The lower elastic modulus of the resins (2.4 Gpa), [19] compared with gold and porcelain, have produced a larger bending of the prosthesis and, consequently, greater bending of the implants toward the pontic thus leading to areas of concentrated stress on the implant and, to a lesser extent, in the cortical bone. [19] The stress transmission to the implant by acrylic prosthesis favors the concept of progressive loading, in which it is considered that a minimum amount of stress is necessary for bone remodeling and osseointegration. [20],[21],[22]

The differences in the stress values among the various materials can be attributed to the difference in the elastic modulus of the different materials, with the rigid materials transferring minimal stress. The metal ceramic and Ni Cr frameworks were more resistant to deformation because of their superior mechanical properties, and the structural differences in frameworks in turn affected the stress distribution in implant structure and bone. [11] Benzing et al.[23] have stated that the rigidity of the superstructure material had an influence on the bone stress concentration and that use of a material with low elastic modulus induced a high risk of mechanical overloading. The stress value observations were similar to those reported in the study done by Papavasiliou et al., [24] Bassit [8] and Cibirka et al. [9] This study indicated that different stress values were obtained but that they did not have any marked significance. All models demonstrated concentration of stresses at the abutment crown junction. A similar pattern of stress was also reported in other FEA of loaded implants with or without superstructure. [25],[26],[27],[28],[29],[30],[31] The location of the stress is consistent with the findings from experiments and clinical studies that demonstrated that bone loss begins around the implant abutment crown interface. [32],[33],[34],[35] These findings support the theory that high stress from inadvertent loading could lead to bone resorption around the implant collar. [33],[34],[35],[36],[37]

With different cuspal angulations in all the models, the stress values increased with an increase in the cuspal angulation. The 33° angulation produced the maximum stresses, which denotes that inclination of cusps generates more stress to the implant.


   Conclusion Top


Within the parameters, design and limitations of the analyses, the following conclusions were made:

  • The maximum stress occurred at the framework in all the materials except acrylic, in which it occurred on the implant.
  • In the framework, maximum stress was recorded at the abutment-crown interface.
  • Increased cuspal angulation resulted in greater stress.
  • Using a rigid superstructure material will transfer minimal stress to the implant and the supporting bone.
  • By minimizing the cuspal inclination, lesser stress will be transferred.
  • Although there are variations in the stress values among the different materials, none of them recorded a stress that would be detrimental on the implant and the supporting bone.
  • The designing of the occlusal morphology plays a significant role in the stress transmission to the implant and supporting bone.


 
   References Top

1.Ishigaki S, Nakano T, Yamada S, Nakamura T, Takashima F. Biomechanical stress in bone surrounding an implant under simulated chewing. Clin Oral Implants Res 2003;14:97-102.  Back to cited text no. 1
[PUBMED]    
2.Skalak R. Biomechanical considerations in osseointegrated prostheses. J Prosthet Dent 1983;49:843-8.  Back to cited text no. 2
[PUBMED]    
3.Lindquist LW, Rockler B, Carlsson GE. Bone resorption around fixtures in edentulous patients treated with mandibular fixed tissue integrated prostheses. J Prosthet Dent 1988;59:59-63.  Back to cited text no. 3
[PUBMED]    
4.Weinberg LA, Kruger B. A comparison of implant/prosthesis loading with four clinical variables. Int J Prosthodont 1995;8:421-33.  Back to cited text no. 4
[PUBMED]    
5.Holst S, Geiselhoeringer H, Wichmann M, Holst AI. The effect of provisional restoration type on micromovement of implants. J Prosthet Dent 2008;100:173-82.  Back to cited text no. 5
[PUBMED]    
6.Davis DM, Rimrott R, Zarb GA. Studies on frameworks for osseointegrated prostheses: Part 2. The effect of adding acrylic resin or porcelain to form the occlusal superstructure. Int J Oral Maxillofac Implants 1988 Winter;3:275-80.  Back to cited text no. 6
    
7.Sertgöz A. Finite element analysis study of the effect of superstructure material on stress distribution in an implant-supported fixed prosthesis. Int J Prosthodont 1997;10:19-27.  Back to cited text no. 7
    
8.Bassit R, Lindström H, Rangert B. In vivo registration of force development with ceramic and acrylic resin occlusal materials on implant-supported prostheses. Int J Oral Maxillofac Implants 2002;17:17-23.  Back to cited text no. 8
    
9.Cibirka RM, Razzoog ME, Lang BR, Stohler CS. Determining the force absorption quotient for restorative materials used in implant Occlusal surfaces. J Prosthet Dent 1992;67:361-4.  Back to cited text no. 9
[PUBMED]    
10.Stegaroiu R, Sato T, Kusakari H, Miyakawa O. Influence of restoration type on stress distribution in bone around implants: A three-dimensional finite element analysis. Int J Oral Maxillofac Implants 1998;13:82-90.   Back to cited text no. 10
[PUBMED]    
11.Sevimay M, Usumez A, Eskitascioglu G. The influence of various Occlusal materials on stresses transferred to implant-supported prostheses and supporting bone: A three-dimensional finite-element study. J Biomed Mater Res B Appl Biomater 2005;73:140-7.  Back to cited text no. 11
[PUBMED]    
12.Quirynen M, Naert I, van Steenberghe D. Fixture design and overload influence marginal bone loss and fixture success in the Brånemark system. Clin Oral Implants Res 1992;3:104-11.  Back to cited text no. 12
[PUBMED]    
13.Isidor F. Loss of osseointegration caused by occlusal load of oral implants. A clinical and radiographic study in monkeys. Clin Oral Implants Res 1996;7:143-52.   Back to cited text no. 13
[PUBMED]    
14.Ciftçi Y, Canay S. The effect of veneering materials on stress distribution in implant-supported fixed prosthetic restorations. Int J Oral Maxillofac Implants 2000;15:571-82.  Back to cited text no. 14
    
15.Gracis SE, Nicholls JI, Chalupnik JD, Yuodelis RA. Shock-absorbing behaviour of five restorative materials used on implants. Int J Prosthodont 1991;4:282-91.  Back to cited text no. 15
[PUBMED]    
16.Chander NG, Padmanabhan TV. Finite element stress analysis of diastema closure with ceramic laminate veneers. J Prosthodont 2009;18:577-81.  Back to cited text no. 16
[PUBMED]    
17.Geng JP, Tan KB, Liu GR. Application of finite element analysis in implant dentistry: a review of the literature. J Prosthet Dent 2001;85:585-98.  Back to cited text no. 17
[PUBMED]    
18.Eskitascioglu G, Usumez A, Sevimay M, Soykan E, Unsal E. The influence of occlusal loading location on stresses transferred to implant-supported prostheses and supporting bone: A three-dimensional finite element study. J Prosthet Dent 2004;91:144-50.  Back to cited text no. 18
[PUBMED]    
19.Stegaroiu R, Kusakari H, Nishiyama S, Miyakawa O. Influence of prosthesis material on stress distribution in bone and implant: A 3-dimensional finite element analysis. Int J Oral Maxillofac Implants. 1998;13:781-90.  Back to cited text no. 19
    
20.Vaillancourt H, Pilliar RM, McCammond D. Finite element analysis of crestal bone loss around porous-coated dental implants. J Appl Biomater 1995;6:267-82.  Back to cited text no. 20
[PUBMED]    
21.Assunção WG, Gomes EA, Barão VA, Delben JA, Tabata LF, de Sousa EA. Effect of superstructure materials and misfit on stress distribution in a single implant-supported prosthesis: A finite element analysis. J Craniofac Surg 2010;21:689-95.  Back to cited text no. 21
    
22.Block MS, Gardiner D, Kent JN, Misiek DJ, Finger IM, Guerra L. Hydroxyapatite-coated cylindrical implants in the posterior mandible: 10 year observations. Int J Oral Maxillofac Implants 1996;11:626-33.  Back to cited text no. 22
[PUBMED]    
23.Benzing UR, Gall H, Weber H. Biomechanical aspects of two different implant-prosthetic concepts for edentulous maxillae. Int J Oral Maxillofac Implants 1995;10:188-98.  Back to cited text no. 23
[PUBMED]    
24.Papavasiliou G, Kamposiora P, Bayne SC, Felton DA. Three-dimensional finite element analysis of stress-distribution around single tooth implants as a function of bony support, prosthesis type, and loading during function. J Prosthet Dent 1996;76:633-40.  Back to cited text no. 24
[PUBMED]    
25.Misch CM, Ismail YH. Finite element stress analysis of tooth-to-implant fixed partial denture designs. J Prosthodont 1993;2:83-92.  Back to cited text no. 25
[PUBMED]    
26.Meijer HJ, Starmans FJ, Steen WH, Bosman F. Location of implants in the interforaminal region of the mandible and the consequences for the design of the superstructure. J Oral Rehabil 1994;21:47-56.  Back to cited text no. 26
[PUBMED]    
27.Juodzbalys G, Kubilius R, Eidukynas V, Raustia AM. Stress distribution in bone: single-unit implant prostheses veneered with porcelain or a new composite material. Implant Dent 2005;14:166-75.  Back to cited text no. 27
[PUBMED]    
28.Sato T, Kusakari H, Miyakawa O. Three dimensional finite element analysis of bone around dental implants in posterior mandibular region: Biomechanics of implant connections. J Jpn Prosthodont Soc 1996;40:682-94.  Back to cited text no. 28
    
29.Lozada JL, Abbate MF, Pizzarello FA, James RA. Comparative three dimensional analysis of two finite-element endosseous implant designs. J Oral Implantol 1994;20:315-21.   Back to cited text no. 29
[PUBMED]    
30.Melo C, Matsushita Y, Koyano K, Hirowatari H, Suetsugu T. Comparative stress analyses of fixed free-end osseointegrated prostheses using the finite element method. J Oral Implantol 1995;21:290-4.   Back to cited text no. 30
[PUBMED]    
31.Murphy WM, Williams KR, Gregory MC. Stress in bone adjacent to dental implants. J Oral Rehabil 1995;22:897-903.  Back to cited text no. 31
[PUBMED]    
32.Hoshaw SJ, Brunski JB, Cochran GV. Mechanical loading of Brånemark implants affects interfacial bone modeling and remodeling. Int J Oral Maxillofac Implants 1994;9:345-60.  Back to cited text no. 32
    
33.Ichikawa T, Miyamoto M, Horisaka Y, Horiuchi M. Radiographic analysis of a two-piece apatite implant: Part II. Preliminary report of 2-year observation. Int J Oral Maxillofac Implants. 1994;9:214-22.  Back to cited text no. 33
    
34.Rangert B, Krogh PH, Langer B, Van Roekel N. Bending overload and implant fracture: A retrospective clinical analysis. Int J Oral Maxillofac Implants 1995;10:326-34.   Back to cited text no. 34
[PUBMED]    
35.Lekholm U, Sennerby L, Roos J, Becker W. Soft tissue and marginal bone conditions at osseointegrated implants that have exposed threads: A 5-year retrospective study. Int J Oral Maxillofac Implants 1996;11:599-604.  Back to cited text no. 35
[PUBMED]    
36.Isidor F. Loss of osseointegration caused by occlusal load of oral implants. A clinical and radiographic study in monkeys. Clin Oral Implants Res 1996;7:143-52.  Back to cited text no. 36
[PUBMED]    
37.Naert I, Quirynen M, van Steenberghe D, Darius P. A six-year prosthodontic study of 509 consecutively inserted implants for the treatment of partial edentulism. J Prosthet Dent 1992;67:236-45.  Back to cited text no. 37
[PUBMED]    

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Correspondence Address:
N Gopi Chander
Department of Prosthodontics, SRM Dental College, Ramapuram, Chennai, Tamilnadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9290.118384

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