Influence of connector size and ceramic type on stress distribution in fixed partial denture with endocrown and inlay retainers: A finite element analysis

Abstract

Background: The present study aimed to evaluate endocrown and inlay as retainers of fixed partial
denture (FPD) and to compare the effect of restoration design, ceramic type, and connector size
on stress distribution using finite element analysis.
Materials and Methods: Cone‑beam computed tomography of the patient was selected and
entered into Catia v5‑21 software for modeling. Then, FPD was designed to replace the second
premolar. Three restoration materials including lithium disilicate (LDS), zirconia reinforced lithium
silicate (ZLS) and Zirconia (Zr) and three connector size including 4×4, 3×4, 3×3 mm, and in terms
of preparation design as both retainer endocrown (EE), both inlay (II), first premolar inlay and first
molar endocrown (IE), and first premolar endocrown and molar inlay (EI). Finally, the mechanical
information was entered into the Ansys software (ANSYS Inc.). Then the mesh sub‑regions were
defined. Finally, a force of 300 Newton was applied vertically and at an oblique. Then, the maximum
stress level and its location were compared and examined among the different study groups, and
finally, the data were assessed.
Results: The minimum stress level was observed in the EI‑LDS with 3 × 4 connector size under
vertical loading (55.1 MPa), and the highest stress level was observed in the IE‑Zr with 3 × 4
connector dimension under oblique loading (558.8 Mpa). The lowest strain (0.5) was observed in the
EI‑Zr with 4 mm × 4 mm connector size under vertical loading. Conversely, the highest strain (4.1)
was seen in the EE‑LDS with a 4 mm × 3 mm connector under oblique loading.
Conclusion: Partial ceramic restorations may serve as effective conservative alternatives to
conventional full crowns as retainers for posterior FPDs.
Key Words: Endocrown, fixed partial denture, inlay, lithium disilicate, zirconia, zirconia
reinforced lithium silicate

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 Marzieh Alikhasi: Pubmed,Google Scholar