Keywords : Composite
Al-Rafidain Dental Journal,
Volume 12, Issue 1, Pages 89-95
Aims: The aim of this study is to evaluate the effect of aluminum oxide as a surface treatment on shear bond strength of etched and non-etched GIC for sandwich restoration with different types of tooth co-lored restorations .In addition, failure type was assessed. Materials and Methods: Sixty Teflon molds (5mm diameter and 4mm height) of a chemically cured GIC were prepared. They were divided into two main groups 1st control, 2 ed air-abraded with 50μm aluminum oxide particles. Both groups were sub divided into two subgroups 1st control, 2 ed etched with 37%phosphoric acid. Bonding material was applied to the treated surface of all groups and cured. The second split of Teflon mold (3mm di-ameter and 4mm height)was placed onto the prepared specimenEach subgroups (1st control, 2 nd etched with phosphoric acid) were farther subdivided into three subgroups which entrain filled as fal-low: 1st split filled with a tg microhybrid, in 2 ed split filled with tg fine glass, and in 3 rd split filled with Ceram X. Shear bond strength was measured by using Universal Testing Machine, and mode of failure examined by a stereomicroscope. Results: Anova test showed that there was a highly significant difference for all variables except acid etching effect. Aluminum oxide surface treatment displays supe-rior shear (2.280MPa). tg micro hybrid composite and Ceram X showed highest shear bond strength. Conclusions: Phosphoric acid etching did not improve shear value of sandwich restorations, while uses of aluminum oxide surface treatment, tg micro hybrid and Ceram X filling material gave an improve-ment on it. The failures were mainly cohesive within the GIC except tg fine glass was cohesive in fill-ing material itself.
The Effect of Two Bonding Agents Generations On Microleakage Of Composite Resin Using Two Light Curing Systems.
Al-Rafidain Dental Journal,
Volume 11, Issue 1, Pages 139-145
Aim: To evaluate the effect of two bonding systems and two curing systems on sealing ability of class V composite restorative materials. Materials and methods: This study was performed in vitro on 40 caries free upper first premolar teeth. The Standardized class V cavity preparation on buccal and lin-gual surfaces of each tooth was done. Then the teeth were randomly divided into two major groups each of twenty. 40 cavities were performed on these teeth and the first group7th generation bonding agent (i Bond) were applied according to the manufacturer instructions and single increment of univer-sal composite (XRV Herculite) from kerr were applied and twenty of the cavities were cured with con-ventional light cure device (astralis-5) and the other twenty cavities were cured with a LED. While the second group 5th generation (Excite bonding agent) applied according to the manufacturer instructions. And filled with universal composite (tetric).Twenty of the cavities light cured with conventional light cure device and the other twenty cavities cured with LED light cured device. Then the teeth were stored in normal physiological saline in an incubator at (37Co) half of each sub group (10 cavities) were stored for one day and the second half stored for one week. Then the teeth were thermo cycled for (200) cycles, after thermo cycling all teeth were immersed in a freshly prepared solution of 2% methylene blue for (24) hours at (37Co). Results: The results showed that there was no statistically significant difference between samples cured using conventional light curing system and those cured using LED light curing system. The type of bonding system and composite material used in this study had no sig-nificant effect on reducing microleakage. Samples aged for seven days produced significantly higher levels of microleakage than that for one day. Conclusions: All samples in this study showed microlea-kage with different levels. Microleakage increases as the age increases. Neither the types of light curing system nor the types of bonding were able to reduce microleakage.
Al-Rafidain Dental Journal,
Volume 7, Issue 3, Pages 10-17
Aims: To compare the shear bond strength (SBS) of composite bonded to dentin cured by three light
curing units (LCUs), which are quartz tungsten halogen (QTH) and two types of light emitting diode
(LED) machines. Materials and Methods: Buccal dentin of 90 upper premolars was exposed, prior to
restorative procedure. Samples divided into 3 groups, restoration of each group cured by Astralis 5
[Austria], Top Light, [Taiwan] and Ultradent [USA]. Each group further subdivided into three
subgroups. After bonding application, each subgroup of every group restored by one of 3 composites:
Point 4™, Tetric and Degufill mineral. Composite applied and cured for 40 seconds. Samples
thermocycled and loaded at tooth–composite interface. Results: Analysis of variance (ANOVA) with
significance p < 0.05 followed by Duncan Multiple Range Test, showed that SBS of subgroups that
cured by Ultradent (400 mW/cm2) was significantly higher than Astralis 5 (405 mW/cm2) and Top
Light (141 mW/cm2). The SBS of Astralis 5 was significantly higher than Top Light. No significant
differences found among subgroups those cured by same LCU. Conclusions: Shear bond strength of
resin composite bonded to dentin is directly proportional with the light intensity. However, better result
obtained by a high intensity LEDs compared with an equivalent intensity QTH–LCUs.