TY - JOUR ID - TI - Effect of different metal surface treatments on microleakage of the two types of acrylic resin: Heat cure and light cure at Co/Cr interface AU - Shatha S. Al-Ameer AU - Firas A. Farhan PY - 2009 VL - 21 IS - 3 SP - 31 EP - 36 JO - Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد SN - 18171869 23115270 AB - ABSTRACT
Background: The microleakage (M.L) at the metal-resin interface in a removable partial denture may results in
discoloration, fluid percolation, and acrylic resin deterioration. Enhancing resistance to microleakage at this interface
may improve the long-term union between the two materials (alloy and acrylic resin). The aim of this study was to
determine the effect of various metal surface treatments on microleakage and bonding between the metal alloy
and acrylic resin used in the fabrication of a removable partial denture.
Materials and Methods: Sixty rectangular Co/Cr samples (50 mm x 25 mm x 1 mm) were prepared and they had a
grid pattern, which formed 50 squares which then divided into 2 groups according to the type of acrylic resin
received each one 30 samples {A- for heat cure resin (HCR), B- for visible light cure resin (VLCR)} which were
subdivided according to the type of surface treatments into 3 subgroups each one 10 samples (A1 B1 for Air
Abrasion -- A2 B2 for Metal Prime II (MP II) application -- A3 B3 for combination of Air Abrasion and Metal Primer II
application). Each sample was divided into experimental half (treated) and a control half (untreated). The samples
were thermocycled (3000 cycles, 5 °C to 50 °C with a dwell time of 1 minute) after application of resin, and placed in
sodium fluorescein (0.2 g / 1000 mL) dye solution (Uranine dye, BDH chemicals Ltd Poole, England) for 48 hours. If the
penetration of the dye was not more than half of the square it was recorded half square and if it was more than half
it was recorded as one square.
Results: The results showed that the subgroup that received Air Abrasion + Metal Primer II surface treatments for both
types of resins HC and VLC (A3 and B3) had the least M.L values, followed by the Air Abrasion subgroup (A1 and B1).
Subgroups that received Metal Primer II alone (A2 and B2) showed the highest M.L value than the other subgroups.
All Co/Cr samples with VLCR showed less dye penetration than that of HCR whether with surface treatment or
without suggesting higher binding of resin with the Co/Cr surface.
Conclusion: A combination of air abrasion and MP II for light cure samples showed the highest reduction in M.L
compared to all other types of surface treatments and to HCR. MP II alone was less effective in reduction of M.L than
other surface treatments. The use of VLCR with different metal surface treatments revealed greater reduction in M.L
than that when used HCR even when there is no surface treatment.
Keywords: Co/Cr- heat and light cure resin interface, metal surface treatments, microleakage. (J Bagh Coll Dentistry
2009; 21(4):31-36)

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