Dentistry. Water-based cements. Resin-modified cements
1Key Takeaways
This document specifies requirements and test methods for water-based dental cements which cure by a combination of acid-base and polymerization reactions. These materials are used for bonding, bases or linings, restorations and core construction. Example: Conventional glass polyolefin ester cements are typically forme…
2Expert Interpretation
This article provides an in-depth analysis of the technical requirements for resin-modified water-based dental adhesives in BS EN ISO 9917-2:2017, including classification, performance test methods (such as working time, setting time, film thickness, and flexural strength), packaging and labeling specifications, and clinical application guidelines. It also covers the major technical revisions in the 2017 version compared to the 2010 version.
Interpretation of the core content of the standard
| Technical parameters | Backing/lining materials | Repair materials | Adhesive materials |
|---|---|---|---|
| Flexural strength (MPa) | ≥10 | ≥50 | ≥25 |
| Working time (min) | ≥manufacturer's declared value and meet the lower limit of Table 1 | ||
| Film thickness (μm) | - | ≤declared value+5 and ≤25 | |
Material classification system
Based on the curing characteristics of the polymer components, it is divided into three categories:
- Category 1: Polymerization is activated by mixing the components
- Category 2: Polymerization requires light irradiation
- Category 3: Dual mechanism of mixing activation and light activation
Resin-modified glass ionomer cementTypical application case: When repairing Class II cavities in posterior teeth, its dual curing properties are used to ensure sufficient curing in deep areas.
Key Test Methods
1. Working Time Determination
Using a 2mm diameter indenter with a load of (28.00±0.25)g, test whether a complete indentation can be formed on the material surface at 37°C.
2. Film Thickness Test
Apply a pressure of 150N between two optical plates and measure the thickness of the cured cement layer. At least 4 out of 5 tests must be ≤25μm.
3. Radioactivity Test
According to ISO 13116:2014, the radioactivity density of a 1mm thick specimen should be ≥ that of an aluminum sheet of the same thickness (when declared radioactive).
Major revisions of the 2017 edition
- Adoption of ISO 13116 as the new benchmark for radioactivity testing
- Expansion of the scope of application to dental core construction materials
- Optimization of technical details in the test method
Implementation recommendations
Key points in clinical operation:
- Strictly follow the powder-liquid ratio specified by the manufacturer
- Light-curing materials must be irradiated in layers and the energy output must be ≥300mW/cm²
- The bonding operation must be completed before the end of the working time
Quality control:Regularly verify the material's flexural strength (three-point bending method) and radioactivity (aluminum equivalent comparison).