Cavity cleansers in restorative dentistry. Preliminary results from an in vitro scanning electron microscope study.
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Acetates↗
Biomedical subjects
A C Shortall
Publications and source records attributed to A C Shortall.
Composite inlay/luting resin bond strength--surface treatment effects.
PURPOSE: To investigate the effect of surface treatments on the bond strength between two resin' composite inlay materials and their luting materials. MATERIALS AND METHODS: A notched disc specimen design was used to evaluate the torque to fracture: test specimens consisting of two half notched disc specimens bonded together, controls consisting of complete resin composite material specimens. RESULTS: Both surface treatment and bond resin application had a significant influence on interfacial bond strength--the torque required to initiate failure being expressed as a percentage of the value required to fracture the control specimens. CONCLUSION: The results allow conclusions to be drawn regarding the attainment of optimal bonding between the resin composite inlays and luting materials investigated.
Bisphenol A-Glycidyl Methacrylate↗
Two-body wear of dental composites under different loads.
PURPOSE: Although dental composites are excellent for restoring the appearance of natural tooth tissues, their relatively poor resistance to wear, especially in approximal and occlusal contact areas, is still a major source of concern. The aim of this research was to study a basic wear mechanism, under 2-body wear conditions, that may be integrated into our understanding of the in vitro and in vivo wear behavior of dental composites. MATERIALS AND METHODS: An in vitro 2-body wear test was conducted on 2 selected ultrafine compact-filled dental composites under different magnitudes of sinusoidal cyclic load. The wear surfaces and cross sections of the wear layers were assessed using scanning electron microscopy (SEM) to explore the nature of the wear pattern of the dental composites under cyclic loading conditions. RESULTS: The wear losses of both composites increased with load. SEM analysis of wear surfaces and subsurface sections indicated that the composites tested displayed different wear mechanisms from low to high loads. An explanation for the wear pattern is proposed based on the observed wear behavior. CONCLUSION: The in vitro wear pattern of the ultrafine compact-filled dental composites tested is closely related to the applied load. Although the wear loss increased in a roughly linear relationship with applied load, the underlying wear mechanism involved may experience a significant change from low to high load conditions during wear.
Bisphenol A-Glycidyl Methacrylate↗
Fracture resistance of anterior, posterior and universal light activated composite restoratives.
This investigation measured the fracture resistance of a wide range of currently available light-activated-composite restoratives. Products intended solely for anterior use were tested together with universal materials and products intended for posterior application. All materials were handled according to manufacturers' instructions. For products evaluated in this investigation, universal and posterior materials yielded higher mean torque to fracture (T) values overall in comparison to the anterior products. One Microfilled and two Polyglas filled products designated for posterior application yielded relatively modest mean fracture resistance values.
Analysis of Variance↗
Influence of bonding agent composition on flexural properties of an Ultra-High Molecular Weight Polyethylene Fiber-Reinforced Composite.
This study evaluated the influence of seven commercially available bonding agents on the flexural properties of an Ultra High Molecular Weight Polyethylene (UHMWPE) Fiber-Reinforced Composite (FRC). Nine groups (n=10 per group) of flexural strength specimens were prepared from an indirect composite reinforced with UHMWPE fiber and cured according to manufacturers' instructions (Groups A to I). Group I was a fiber-reinforced negative control without any bonding agent resination. A tenth group (Group J) was a positive control group prepared using indirect composite alone. The fiber reinforcement material for Groups A to H was resinated with one of the seven different bonding agents. Group H used the same bonding agent as for Group G specimens. However, the fiber was silanized before bonding agent application for Group G specimens. Specimens were stored wet for 24 hours at 37 degrees C before measuring flexural strength and modulus in three-point bend at a crosshead speed of 1 mm/minute. Scanning Electron Microscopy (SEM) was employed to assess the fiber-resin interface of representative samples. The mean (SD) flexural strength of the test groups impregnated by the bonding agents ranged from 169 (37) to 266 (39) MPa. Statistical analysis of the flexural strength data using one-way ANOVA revealed significant (p<0.05) differences between the test groups. There was catastrophic fiber/composite failure in the positive control group that had a mean flexural strength of 75 (8) MPa. Silane pre-treatment of UHMWPE fiber before impregnation with the bonding agent significantly reduced the flexural strength (p<0.05).
Acetone↗
Marginal seal comparisons between resin-bonded Class II porcelain inlays, posterior composite restorations, and direct composite resin inlays.
The microleakage of indirect porcelain and direct composite resin-bonded inlays was compared with that of posterior composite resin restorations using Class II preparations of extracted molar teeth. The resin-bonded inlay restorations provided a better marginal seal at the cervical restoration/dentin interface than did the composite resin restoration. The efficacy of this marginal seal varied with the particular treatments and materials used. Resin-bonded porcelain inlays had a higher incidence of cervical excess from the composite resin luting agent than did the posterior composite resin restorations.
Composite Resins↗