Category: Laboratory Research
Effects of Reduced Light through Zirconia on the Interfacial Adaptation
Seung-Hoon Hana* (han7537@hotmail.com)| Yasushi Shimadac | Alireza Sadrc
aSt. Vincent Hospital, College of Medicine, The Catholic University of Korea, Suwon, South Korea
bTokyo Medical and Dental University (TMDU), Tokyo, Japan
cSchool of Dentistry, University of Washington, Seattle, WA, USA
Objective: The first objective was to determine if dual-curing of resin cement with reduced light could affect interfacial adaptations of zirconia restoration. The second objective was to examine whether pretreatment method of universal adhesive affected interfacial adaptation.
Methods: Inlay cavities were prepared on extracted human third molars. Zirconia restorations were fabricated using Katana UTML (Kuraray Noritake). The teeth were divided into three dual-cure groups and one self-cure group: Groups I, II, III and self-cure group. Each restoration thickness of Group I, II, and III was 1, 2, and 3 mm. Each group had two subgroups according to different pretreatment methods. For subgroup 1, universal adhesive (Single Bond Universal, 3M ESPE) was applied and light-cured before cement placement. Then, zirconia restoration was seated with conventional resin cement (RelyX Ultimate, 3M ESPE). Light-curing was executed for the cement. For subgroup 2, after adhesive was applied, the restoration was seated with the same resin cement. Light-curing was done for adhesive and cement simultaneously. For the self-cure groups, cements were all polymerized by the self-curing method. Subgroups differ depending on the pretreatment method as those of dual-cure groups. After thermo-cycling of zirconia restoration, interfacial adaptation at the restoration-tooth interface was investigated using swept-source optical coherence tomography imaging.
Results: Interfacial adaptation varied depending on the zirconia thickness, pretreatment, polymerization mode (p<0.05). The effects of the adhesive differed depending on the reduced light under the zirconia (p<0.05).
Conclusion: Lower curing-light irradiance may lead to inferior adaptation of zirconia restoration.
Funding/Conflict of Interest: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2020R1G1A1101924).
Keywords: optical coherence tomography, resin cements
