Effect of Shelf Life of Light Cure Resin Cement on the Shear Bond Strength of IPS EMAX PRESS Ceramic: (An In vitro Study)

Abstract

Background: Achieving durable bonding for all ceramic restorations will affect its long‑term
survival in the oral cavity. Dentists may use resin cement after its shelf lifetime, especially in
low socioeconomic conditions, which may affect the success and longevity of restorations. The
purpose of this in vitro study was to evaluate how the duration of shelf life impacts the shear bond
strength (SBS) of lithium disilicate ceramics using light‑cured resin cement.
Materials and Methods: An in vitro comparative study investigated the impact of resin
cement expiry on the SBS of pressed lithium disilicate ceramics. Twenty‑four IPS e.max Press
discs (4 mm × 2 mm) were randomly divided into two groups: Group I used unexpired light‑cured
resin cement, and Group II used expired cement. Each disc was bonded to enamel surfaces from
sectioned maxillary incisors to create test specimens. Following thermocycling, samples were
subjected to a shear force using a universal testing machine until debonding occurred, and the failure
load was recorded. Data normality was confirmed with the Shapiro–Wilk test, mean SBS values
were compared through independent t‑test, and failure modes were assessed using the Chi‑square
test with Monte Carlo correction at a significance level of P < 0.05.
Results: Group I exhibited a higher SBS with a mean value of 24.98 ± 4.01 MPa compared to
Group II with a mean value of 20.39 ± 2.72 MPa, with a mean P = 0.008.
Conclusion: Expiry date affected the SBS of light‑cured resin cement to lithium disilicate ceramic
materials. But still the recorded value is higher than the recommended clinical accepted value.
Key Words: Ceramics, dental bonding, dental cements, in vitro techniques, shear strength

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 Yasser M. Aly: Pubmed,Google Scholar