In dental restoration, the selection of restorative materials that are biocompatible, strong, and possess adequate mechanical properties is essential for long-term success. Biocompatibility refers to a material’s ability not to irritate biological tissues, to maintain pulp and surrounding tissue health, and, where possible, to exhibit anticariogenic properties.
One commonly used material is glass ionomer cement (GIC). The advantages of GIC include:
- The ability to release fluoride, which helps prevent caries
- Chemical adhesion to tooth structure
- Good biocompatibility
However, the limitations of GIC include relatively weaker mechanical properties—such as tensile, compressive, and flexural strength—compared to some other restorative materials, particularly when used in areas subjected to high masticatory loads.
Case Study: Silanized Micro Sisal in GIC
A study conducted by an FKG UGM student, TIARA ATIKA JUANITA, under the supervision of Prof. Dr. drg. Widjijono, S.U. and Prof. Dr. drg. Widowati S, M.S., entitled “Variasi Kadar Penambahan Sisal Mikro Tersilanisasi terhadap Kekuatan Tarik Semen Ionomer Kaca Konvensional”, explored the use of natural reinforcement to improve the tensile strength of conventional GIC.
Research Methods:
- Materials: Conventional GIC (Fuji II GC, Japan) and sisal fibers (Agave sisalana) sourced from Balittas, Indonesia.
- Sisal fiber treatment: Microfibers were produced through processes including scouring, neutralization, bleaching, hydrolysis, and drying, followed by silanization (addition of a silane coupling agent) to enhance adhesion between the fibers and the GIC matrix.
- Variations in silanized micro sisal content (weight/weight): 0% (control), 1%, 3%, and 5%.
- Sample shape: Dumbbell-shaped specimens measuring 30 mm × 4 mm × 2 mm, tested for tensile strength using a Universal Testing Machine.
Results:
- Average tensile strength of GIC for each group: • Control (0% sisal): ~5.63 ± 1.04 MPa • 1% sisal addition (P1%): ~10.63 ± 1.33 MPa • 3% sisal addition (P3%): ~13.13 ± 1.04 MPa • 5% sisal addition (P5%): ~12.50 ± 0.88 MPa
- Statistical analysis (one-way ANOVA and post hoc LSD) showed that variations in silanized micro sisal content had a significant effect on increasing the tensile strength of conventional GIC.
- Main conclusion: The optimal silanized micro sisal content for improving the tensile strength of conventional GIC was 1% w/w.
Implications for the Selection of Biocompatible Restorative Materials
Based on the findings, several important points emerge regarding the improvement of biocompatible materials such as GIC for dental restoration:
- Biologically Derived Material Reinforcement
Properly processed natural fibers, such as sisal, can serve as effective reinforcement, enhancing mechanical properties without compromising biocompatibility. - Balance Between Biocompatibility and Mechanical Properties
Reinforcement levels must be optimized to avoid disrupting other essential properties such as adhesion, fluoride release, and biological compatibility. While additions of 1–5% silanized micro sisal improved tensile strength, 1% was considered optimal in this study. Higher levels did not provide proportional benefits and may even result in slight reductions (e.g., at 5% compared to 3%). - Effect of Fiber Treatment and Adhesion on Material Composition
Fiber treatments such as silanization are critical for enhancing bonding between fibers and the GIC matrix, allowing better mechanical load distribution and reducing microgaps, which also affects restoration durability. - Clinical Considerations
- Restorations subjected to tensile stress should consider reinforced materials such as GIC with added reinforcement
- Conventional GIC may be sufficient for low-load restorations, but reinforced materials are safer for areas expected to experience higher tensile stress (e.g., interproximal regions or large restoration finish lines).
- Setting time, integration with tooth tissues, and biological responses must remain key considerations to avoid adverse effects.
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An ideal dental restorative material should be biocompatible, capable of fluoride release (when possible), demonstrate good adhesion to tooth structure, and possess adequate mechanical strength for long-lasting restorations. Research on the addition of silanized micro sisal to GIC indicates that this biocompatible material can be mechanically strengthened—particularly in tensile strength—with significant improvement at a concentration of 1% w/w.
References
TIARA ATIKA JUANITA, Prof. Dr. drg. Widjijono, S.U ; Prof. Dr. drg. Widowati S, M.S., VARIASI KADAR PENAMBAHAN SISAL MIKRO TERSILANISASI TERHADAP KEKUATAN TARIK SEMEN IONOMER KACA KONVENSIONAL, https://etd.repository.ugm.ac.id/home/detail_pencarian_downloadfiles/581291
Author: Rizky B. Hendrawan | Photo: Freepik
