Related Experiment Video
Updated: Jun 22, 2026
07:42
Quasistatic Mechanical Testing for Computer-Aided Design and Manufacturing Occlusal Veneers Cemented to Milled Dentin Analog Material
Published on: December 20, 2024
Glass ionomer cement hardness after different materials for surface protection
Cecilia R Brito1, Leandro G Velasco, Gabriela A V C Bonini
1Research Department/Council of Researches in Education and Sciences, Santos, Brazil. draceciliabrito@gmail.com
Journal of Biomedical Materials Research. Part A
|June 27, 2009
Summary
Nail varnish significantly improved glass ionomer cement (GIC) hardness, but petroleum jelly is a safer alternative for surface protection. This study evaluated GIC Knoop hardness with various protective coatings.
Area of Science:
- Dental Materials Science
- Biomaterials Engineering
- Surface Chemistry
Background:
- Glass ionomer cement (GIC) is a widely used dental restorative material.
- Surface protection is crucial for maintaining the integrity and longevity of GIC restorations.
- Various protective agents are available, but their efficacy on GIC hardness requires evaluation.
Purpose of the Study:
- To assess the Knoop hardness of a high-viscosity GIC (Ketac Molar Easy Mix) when protected by different surface agents.
- To compare the effectiveness of Copal varnish, adhesive systems, petroleum jelly, and nail varnish against a control group.
Main Methods:
- Sixty GIC specimens were prepared and divided into six groups, each receiving a different surface treatment.
- Specimens underwent Knoop hardness testing initially, after 30 days, and after 4 months.
- Statistical analysis using Two-way ANOVA and Tukey Test was performed to determine significant differences.
Main Results:
- Nail varnish demonstrated a statistically significant increase in GIC Knoop hardness compared to the control group (p < 0.001).
- Copal varnish, adhesive systems (Magic bond, Adper Single Bond 2), and petroleum jelly showed no significant difference in hardness compared to the untreated control.
- No significant differences were observed among the tested materials and the control group after 30 days and 4 months, except for nail varnish.
Conclusions:
- Nail varnish appears to be the most effective surface protection agent for enhancing GIC Knoop hardness.
- Due to potential adverse effects, solid petroleum jelly is suggested as a safer, viable alternative for surface protection of GIC.
- Further research into the biocompatibility and long-term effects of nail varnish on GIC is warranted.
Related Concept Videos
01:22Toughness and Hardness of Aggregate
Toughness and hardness are critical properties of aggregate materials used in concrete, particularly on pavement surfaces and industrial flooring subjected to heavy loads. Toughness is defined as the aggregate's resistance to failure by impact and is measured by the aggregate impact value (AIV). For this, the aggregate impact value test is performed, wherein the impact is delivered by a standard hammer, which falls freely under its own weight onto the aggregates. The aggregates fragment in the...
01:20Strength of Cement
Strength tests for cement are not performed directly on neat cement paste due to difficulty in obtaining consistent, reliable specimens. Instead, cement is typically tested in the form of cement-sand mortar.
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in ASTM C...
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in ASTM C...
01:21Types of Cement I
Portland cement comes in several types, each with distinct properties and applications based on their chemical composition and hydration characteristics:
Type I (Ordinary Portland Cement) is widely used for general construction where special properties are not required. It has moderate sulfate resistance and heat of hydration.
Type II (Modified Cement) offers moderate resistance to sulfate attack and a lower rate of heat development compared to Type I. It is suitable for structures in...
Type I (Ordinary Portland Cement) is widely used for general construction where special properties are not required. It has moderate sulfate resistance and heat of hydration.
Type II (Modified Cement) offers moderate resistance to sulfate attack and a lower rate of heat development compared to Type I. It is suitable for structures in...
01:17Mortar Properties
Mortar properties encompass a range of characteristics crucial for construction and masonry work, including workability, water retention, bond strength, durability, compressive strength, volume change, and appearance. Workability refers to mortar's ability to be easily applied and manipulated without sagging or falling off surfaces, which is important for efficient masonry unit placement and alignment. Water retention is essential to prevent the mortar from losing moisture too quickly to the...
01:22Types of Cement II
Portland blast-furnace cement is made by blending Portland cement clinker with granulated blast-furnace slag, which accounts for 25 to 65 percent of the cement's weight. Despite its similarities to ordinary Portland (Type I) cement in terms of fineness and setting times, its early strength is lower, though it achieves comparable strength later on. It's particularly suited for mass concrete structures and marine environments due to its lower heat of hydration and superior sulfate resistance.
01:15Fineness of Cement
The fineness of cement directly influences the rate of hydration, as the hydration begins at the surface of the cement particles. In addition to hydration, the fineness of cement is vital for various properties of concrete including workability, gypsum requirement, and long-term behavior. The fineness of cement is represented in terms of the specific surface of cement which is typically measured in square meters per kilogram, with several methods available for this determination.
Direct...
Direct...