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2026 Vol.30, Issue 3

Original Article

Directional Prosthesis–Implant Geometry as a Correlate of Eccentric Load Sensitivity Across Axial Inclination–Driven Access-Hole Positions: A Finite Element Analysis
Young K. Kim1*
,
Jermaine Eow2
,
Dung Dinh Luong3
1Clinical Assistant Professor, Department of Prosthodontics, New York University College of Dentistry, NY, USA
2BA/DDS Student, Department of Cariology & Comprehensive Care, New York University College of Dentistry, NY, USA
3Industry Assistant Professor, Department of Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, NY, USA
*Corresponding Author
30 September 2026. pp. 139-156
PDF XML Citation
Abstract

Purpose: To evaluate the associations of axial inclination–driven access-hole position and directional prosthesis–implant geometry with peri-implant biomechanics under eccentric loading, and to assess the prosthesis–implant arch area ratio (PIAAR) as a geometric index of eccentric load sensitivity.

Materials and Methods: Standardized 3D finite element models of a posterior molar implant restoration were constructed to isolate geometric effects. Using controlled axial inclination while maintaining a fixed prosthetic reference, the access-hole position was altered. Directional geometry was quantified using sectorial PIAAR derived from occlusal projections. Models were evaluated under centric axial and 30-degree oblique loading.

Results: Despite a lower aggregate loading magnitude, the localized oblique loading configuration was associated with greater peri-implant stress, which indicated that the interface stress response was not proportional to nominal load magnitude alone but was substantially influenced by load directionality. Higher weakest-direction PIAAR values were consistently associated with greater eccentric stress amplification and greater absolute eccentric stress difference, whereas greater directional spread showed an inverse relationship with both measures. However, this global measure does not establish whether sector-specific stress vulnerability was correspondingly reduced or absent.

Conclusion: Eccentric load sensitivity varied with directionally limiting prosthesis–implant geometry, which suggests that conventional access-hole centricity may incompletely characterize the modeled biomechanical behavior. PIAAR may provide a geometric index for defining directional prosthesis–implant relationships under non-axial loading.

Keywords
Dental implants
Eccentric loading
Finite element analysis
Guided implant planning
Implant biomechanics
Prosthesis–implant arch area ratio
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Information
  • Publisher :The Korean Academy of Oral & Maxillofacial Implantology
  • Publisher(Ko) :대한구강악안면임플란트학회
  • Journal Title :Journal of implantology and applied sciences
  • Journal Title(Ko) :대한구강악안면임플란트학회지
  • Volume : 30
  • No :3
  • Pages :139-156
  • Received Date : 2026-06-18
  • Revised Date : 2026-08-23
  • Accepted Date : 2026-08-28
  • DOI :https://doi.org/10.32542/implantology.2026012
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