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Title:	Influence of thermal expansion on bond strength of nano-zirconia and veneering ceramics
Authors:	Ahlam Mohammed Abdualjabar Almoualimy (P85406)
Supervisor:	Yew Hsu Zenn, Dr.
Keywords:	Dental Veneers Ceramics Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	24-Aug-2020
Description:	The coefficient of thermal expansion (CTE) is believed to be one of the main factors that could influence the coreveneer interface reactions. Aim of study was to elucidate the CTEs of a novel and a commercially available nanozirconia, to compare the CTE differences between nano-zirconias and existing veneering ceramics (VCs) in the market, and to elucidate the effect of CTE mismatch on shear bond strength (SBS) of veneered nano-zirconias. Five cylindrical samples from each core materials (CMs) experimental nano-zirconia (Zir) and Cercon® (Cer) and VCs (Ceram Kiss® (CK), VITA VM9® (VM9), and IPS e.max® (e.max)) were prepared in 24 mm in length and 6 mm in diameter. The samples were tested in rod dilatometer by applying the temperature started from room temperature up to 1400°C for CMs and up to melting temperature point for VCs. Forty-eight cylindrical discs (10 mm in diameter and 3 mm of thickness) were fabricated of Zir and Cer. All CMs were sandblasted with 50μm Aluminum oxide (AL2O3) before VCs were layered on each CMs in the thickness of 3mm. Following storage in distilled water (37°C) for 24 hours, SBS tests were performed on all bonded samples. Field emission scanning electron micrograph (FESEM) was used to identify the mode of bonding failure. The mean CTE (x10‾6/°C) values (with standard deviations) of core materials Zir and Cer were 7.86 (±0.47), and 7.82 (±0.49), respectively. Independent t-test revealed no significant difference between both CMs (p>0.05). CK, VM9, and e.max recorded mean CTE (x10‾6/°C) values 7.20 (±0.62), 7.20 (±0.29), and 7.10 (±0.46), respectively. One-way ANOVA with Tukey post-hoc test confirmed no statistically significant differences between VCs. The highest CTE mismatch was noted in Zir-e.max combinations (0.78), while the lowest difference observed in Cer-VM9 assemblies (0.63). Zir-VM9 revealed the highest mean SBS value 149.48 MPa ±67.64, while Cer-emax group recorded the lowest value 44.07 MPa ± 16.49. Cohesive failure observed in high SBS group, while adhesive failure was seen in low SBS group. The greater the value of CTE mismatch between core and veneer materials, the less the value of SBS and vice versa. Conclusion: CTE discrepancies affect the SBS of veneered zirconia restoration and should be considered when selecting zirconia core-veneer assembly. The experimental nano-zirconia shows similar performance and can be used as an alternative to commercial zirconia,Ijazah Sarjana Sains Pergigian
Pages:	38
Call Number:	WU510.A452i 2020 9 tesis
Publisher:	UKM, Kuala Lumpur
Appears in Collections:	Faculty of Dentistry / Fakulti Pergigian

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