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First Page

1469

Last Page

1479

Abstract

Background/purpose: The biomechanical effects of framework design and material interactions in mandibular free-end saddle removable partial dentures remain unclear. This study evaluated framework variables using finite element analysis.

Materials and methods: A mandibular Kennedy Class II model was digitized to create a cobalt-chromium (CoCr) and sixteen Ti-6Al-4V (Ti64) frameworks varying by major connector dimension, clasp configuration, and lingual reciprocal assembly (LRA). Periodontal ligament (PDL) and mucosa layers were incorporated. Contacts were defined, and materials were assumed homogeneous and isotropic. Vertical and oblique loads were applied, and von Mises stresses were analyzed. Model validation was performed using digital image correlation.

Results: Ti64 frameworks reduced overall stress by 21%–43% compared with CoCr. Under vertical loading, PDL stress decreased by 40% and framework stress by 32%–46%. Under oblique loading, direct retainer, PDL, and mucosal stresses increased by 3%, 6%, and 13%, respectively. Framework stress distribution was governed by clasp–LRA interaction, whereas increasing connector rigidity reduced stress magnitude and variability rather than peak stress. Supporting tissue responses were primarily determined by major connector dimension, with LRA and clasp effects being design- and loading-dependent.

Conclusion: Ti64 frameworks improved load distribution with limited supporting tissue stress increases under oblique loading. Framework behavior was primarily governed by clasp–LRA interaction, while connector dimension determined supporting tissue response. Increasing major connector dimension attenuated LRA-related stress variations, particularly under oblique loading. Coordinated control of clasp configuration, LRA incorporation, and major connector dimension is required for biomechanical optimization.

Publication Date

2026

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