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Influence of phosphoric acid surface treatment on shear bond strength durability of resin cement to zirconia-based ceramic conditioned with different primersAlshehri, Eman Zuhair January 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / BACKGROUND: Phosphoric acid treatment has been reported to be relevant for
zirconia cleaning after contamination. However, its interaction with different primers is
not well known and needs to be investigated. OBJECTIVES: To compare the shear bond
strengths (SBS) of resin cement to Y-TZP after phosphoric acid pretreatment and
different chemical conditioning protocols, and to test the durability of SBSs after long
term storage and thermal cycling conditions. To investigate the effect of phosphoric acid
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on the surface roughness of a yttrium-stabilized tetragonal zirconia polycrystal ceramic
(Y-TZP). METHODS: Sixty bars of zirconia (30 X 5 X 2 mm) were polished and glued
to acrylic tubes. Each bar received 3 different surface treatments (control, phosphoric
acid and air-abrasion). The bars were randomly assigned into five groups according to
different primers applied (No primer, Clearfil ceramic primer, Monobond Plus, Z-prime
plus and AZ primer). After that, resin cement was mixed, injected into a mold, and light
cured. The specimens were tested in shear on a universal testing machine. Half of the
specimens were tested after 24 h water storage and the other half were tested after 90
days of water storage and thermocycling. Non-contact profilometer was used to assess
the effect of the three surface pretreatments on surface roughness of zirconia. Mode of
failure and surface roughness were evaluated with SEM. Statistical analyses were
conducted with mixed-model ANOVA and chi-square tests. RESULTS: The results
indicated that Monobond Plus primer showed higher SBS after phosphoric acid
treatment compared to other primers used. SBS of all air abrasion groups were higher
than phosphoric acid groups. Long term water storage and thermocycling led to a
statistically significant decrease in SBS for all groups except Monobond Plus, Z-prime
plus and AZ primer after air abrasion treatment. Surface roughness measurements showed
no significant differences among the surface treatments. CONCLUSION: Monobond Plus
provided the highest SBS to zirconia after phosphoric acid treatment. The findings
suggest that the air abrasion is the best surface treatment after contamination of zirconia
surface. Monobond Plus, Z-prime plus and AZ primer showed durable SBS after air
abrasion treatment and aging process.
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Influence of saliva contamination on resin bond durability to zirconia - effect of cleaning methodsPatel, Dhara January 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Background and Rationale: As compared with glass-based ceramics, zirconia has gained considerable popularity in restorative dentistry due to its superior mechanical properties. Clinically, however, zirconia ceramics pose a significant challenge regarding the achievement of a reliable and durable bond to resin-based cements. Thus far, it has been established that zirconia bond to resin-based cements can be enhanced after different surface conditioning methods, such as airborne particle abrasion with aluminum oxide particles. Meanwhile, another major issue pertaining to bonding of ceramic restorations is related to its potential contamination before cementation. Briefly, after sandblasting and clinical try-in procedures, zirconia can be contaminated with saliva and/or blood. As with many metals, zirconium shows a strong affinity towards the phosphate group found in saliva and other fluids, which reacts with the zirconia surface and makes bonding very difficult. Recently, a new cleaning agent called Ivoclean® (Ivoclar-Vivadent), which is an alkaline suspension of zirconium oxide particles, has been introduced in the market to remove contamination from zirconia in an effort to improve bonding to resin cements.
Objective: The purpose of this study was to evaluate the influence of saliva contamination and the effect of several cleaning methods, including Ivoclean on resin bond strength to zirconia. Materials and Methods: Eighty square-shaped specimens (ϕ = 12 mm x 12 mm x 3 mm) of yttria-stabilized full-contour zirconia (Diazir®, Ivoclar-Vivadent, Amherst, NY) were sectioned from zirconia blocks using a water-cooled diamond blade. Then, these specimens were embedded in acrylic resin, and their surfaces gradually finished with silicon carbide papers (600 grit to 1200 grit). The prepared zirconia surfaces were sandblasted with 50-μm aluminum oxide particles for 15 s, under 2.5 bars and from distance of 10 mm. After sandblasting the specimens were cleaned in an ultrasonic bath containing distilled water for 5 min and air-dried for 10s. All samples were equally divided into 4 groups (n = 20) according to the cleaning method. Airborne particle abraded specimens without contamination was served as the control group. Remaining groups were contaminated with saliva, and subjected to different cleaning protocols, namely: Ivoclean®, 70% isopropanol, and no treatment. Two resin cement buttons (Multilink – Ivoclar-Vivadent, Amherst, NY) were built over each zirconia surface and light-cured following the manufacturer recommendations. The influence of contamination and surface cleaning methods on ceramic bond durability were examined after 24 h on half of the samples in each group (n = 10, n = 20), and the other half (n = 10, n = 20) specimens will undergo 6000 thermocycles (TC) before shear bond testing in the universal testing machine.
Conclusion of Expected Outcomes: The shear bond strength of resin cement to zirconia led to a significant improvement after cleaning with Ivoclean both immediately and after thermal aging.
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