Influence of Number of Implants and Attachment Type on Stress Distribution in Mandibular Implant-Retained Overdentures: Finite Element Analysis


  • Mohamed I. El-Anwar Mechanical Engineering Department, National Research Centre, Cairo
  • Eman A. El-Taftazany Removable Prosthodontics Department, Faculty of Dentistry, Misr International University, Cairo Governorate
  • Hamdy A. Hamed Removable Prosthodontics Department, Faculty of Oral & Dental Medicine, Cairo University, Cairo
  • Mohamed A. Abd ElHay Removable Prosthodontics Department, Faculty of Dentistry, Misr International University, Cairo Governorate



Finite element analysis, Implant, Overdenture, Attachment


AIM: This study aimed to compare the stresses generated by using two or four root form dental implants supporting mandibular overdentures that were retained with ball and locator attachments.

METHODS: Under ANSYS environment, four 3D finite element models were prepared. These models simulated complete overdentures supported by two or four implants with either ball or locator attachments as a connection mechanism. The models’ components were created by CAD/CAM package then were imported to ANSYS. Load of 100 N was applied at the right premolar/molar region vertically and at an oblique angle of 110° from lingual direction.

RESULTS: Within the conditions of this research, in all cases, it was found that cortical and cancellous bone regions were the least to be stressed. Also, the ball attachment produced higher stresses.

CONCLUSION: Caps deformation and stresses are negligible in cases of using locator attachment in comparison to ball attachments. This may indicate longer lifetime and less repair/maintenance operations in implant overdentures retained by locator attachments. Although the study revealed that bone was insensitive to a number of implants or attachment type, it may be recommended to use two implants in the canine region than using four, where the locator attachments were found to be better.


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Author Biography

Mohamed I. El-Anwar, Mechanical Engineering Department, National Research Centre, Cairo



Wismeijer D, Van Wass MA, Mulder J. Clinical and radiological results of a patient treated with three treatment modalities for overdenture on implants of (ITI) dental implant system. Clin Oral Impl Res. 1999; 10: 297-306.

Gulizio M, Agar J, Kelly R, Taylor T. Effect of implant angulation upon retention of over denture attachments. Int J Prosthodont. 2005; 14:3-11. PMid:15733129

Trakas T, Michalakis K, Kang K, Hirayama H. Attachment systems for implant retained overdentures: a literature review. Impl Dent. 2006; 15: 24–34. PMid:16569958

Alsabeeha NHM, Payne AGT, Swain MV. Attachment systems for mandibular two-implant overdentures: a review of in vitro investigations on retention and wear features. Int J Prosthodont. 2009; 22: 429–440. PMid:20095190

Wang F, Monje A, Huang W, Zhang Z, Wang G, Wu Y. Maxillary Four Implant-retained Overdentures via Locator® Attachment: Intermediate-term Results from a Retrospective Study. Clin Implant Dent Relat Res. 2016;18(3):571-9. PMid:25810348

Youda N, Matsudate Y, Abue M, Hong G, Sasaki K. Effect of attachment type on load distribution to implant abutments and the residual ridge in mandibular implant-supported overdentures. J Dent Biomech. 2015; 6: 1758736015576009.

Krennmair G, Weinlander M, Krainhofner M, Peihslinger E. Implant-supported mandibular overdentures retained with ball or telescopic crown attachments: a 3-year prospective study. Int J Prosthodont. 2006; 19:164-170. PMid:16602365

Sadig W. A comparitive in vitro study on the retention and stability of implant-supported over dentures. Quintessence Int. 2009; 40(4): 313-319. PMid:19417876

Pasciuta M, Grossmann Y, Israel M. A prosthetic solution to restoring the edentulous mandible with limited inter-arch space using an implant-tissue-supported overdenture: A clinical report. J Prosthetic Dent. 2005; 93:116-120. PMid:15674219

Kleis WK, Kammer PW, Hartmann S, Al-Nawas B, Wagner W. A comparison of three different attachment systems for mandibular two implant overdentures: One-year report. Clin Imp Dent Res. 2010; 12: 209-218.

Ibrahim AM, Radi I AW. The effect of two types of attachments on the bone height changes around divergent implants retaining mandibular overdentures. Cairo Dent J. 2009; 25(2): 181-189.

Cordaro L, Di Torresanto VM, Petricevic N, Jornet PR, Torsello F. Single unit attachments improve peri-implant soft tissue conditions in mandibular overdentures supported by four implants. Clin Oral Impl Res. 2013; 24(5):536-42. PMid:22320359

Schneider AL. The use of a self-aligning, low-maintenance overdenture attachment. Dent Today. 2000; 19(4): 24-26. PMid:19750725

Kurian BP, D'lima J, Karthikeyan CR, Mathew J, Paul T, Hareesh MT. Prosthetic efficiency of implant-supported overdentures with locator attachment: A Clinical case report. Journal of International Oral Health. 2015; 7(10):129-132.

Theodoros T, Konstantinos M, Hiroshi H. Attachment systems for implant retained overdentures. J Impl Dent. 2006; 1: 24-34.

Doundoulakis JH, Eckert SE, Lindquist CC, Jeffcoat MK. The implant-supported overdenture as an alternative to complete mandibular denture. J Am Dent Assoc. 2003; 134(11): 1445-8.

Geng J, Yan W, Xu W, editors. Application of the finite element method in implant dentistry. Springer Science & Business Media; 2008 Sep 26.

Huang HL, Chang CH, Hsu JT, Fallgatter AM, Ko CC. Comparison of implant body designs and threaded designs of dental implants: A 3-dimensional finite element analysis. Int J Maxillofac Imp. 2007; 22(4): 551-562.

Lui J, Pans S, Dong J, Mo Z, Fan Y, Feng H. Influence of implant number on the biomechanical behavior of mandibular implant-retained/supported overdentures: a three dimensional finite element analysis. J Dent. 2013; 41(3): 241-249. PMid:23160036

El-Anwar MI, Yousief SA, Soliman TA, Saleh MM, Omar WS. A Finite element study on stresses distribution of two different attachment designs under implant supported overdenture. The Saudi Dental Journal. 2015; 27(4):201-207. PMid:26644755 PMCid:PMC4642187

Muntianu LAS. Analyze of the mechanical stress distribution over implants in mandibular overdenture. Metalurgia Int. 2010; 15(3):24-26.

Ravindra C, Goyal SC. Study of Biomechanics of Porous Coated Root Form Implant Using Overdenture Attachment: A 3D FEA. J Indian Prosthodont Soc. 2010; 10(3):168–175. PMid:21886409 PMCid:PMC3081273

Tada S, Stegaroiu R, Kitamura E, Miyakawa O, Kusakari H. Influence of implant design and bone quality on stress/strain distribution in bone around implants: a three dimensional Finite Element Analysis. Int J Oral Maxillofac Imp. 2003; 18:357–368. PMid:12814310

Kurtzman GM. The locator attachment: Free standing versus bar overdentures. Dent Labor Int plus. 2009; 1(1):20-23.

Evtimovska E, Masri R, Driscoll CF, Romberg E. The change in retentive values of locator attachments and hader clips over time. J Prosthodont. 2009; 18(6):479-483. PMid:19500236

Abdelhamid AM, Assaad NK, Neena AF. Three dimensional finite element analysis to evaluate stress distribution around implant retained mandibular overdenture using two different attachment systems. J Dent Health Oral Disord Ther. 2015; 2(5): 00065.

Ebadian B, Talebi S, Khodaeian N, Farzin M. Stress analysis of mandibular implant-retained overdenture with independent attachment system: effect of restoration space and attachment height. Fixed Removable Hybrid Prosthesis. 2015; 1:61-67.

Bilhan H, Geckili O, Mumcu E, Cilingir A, Bozdag E. The influence of implant number and attachment type on maximum bite force of mandibular overdentures: a retrospective study. Gerodontology. 2012; 29(2):e116-20. PMid:20735488

Hong HR, Pae A, Kim Y, Paek J, Kim HS, Kwon KR. Effect of implant position, angulation, and attachment height on peri-implant bone stress associated with mandibular two-implant overdentures: a finite element analysis. Int J Oral Maxillofac Imp. 2012; 27(5):69-76.



How to Cite

El-Anwar MI, El-Taftazany EA, Hamed HA, Abd ElHay MA. Influence of Number of Implants and Attachment Type on Stress Distribution in Mandibular Implant-Retained Overdentures: Finite Element Analysis. Open Access Maced J Med Sci [Internet]. 2017 Mar. 22 [cited 2022 Oct. 6];5(2):244-9. Available from:



D - Dental Sciences