Glass Ionomer Cements: Indications, Advantages, and Disadvantages

Indications	– Restorative material – Luting cement – Pulp protection – Pit and fissure sealant – Atraumatic restorative technique
Setting Time	2-3 minutes
Type of Reaction	Acid-Base (Chemical)
Types	Type I: Luting Cements Type II: Restorative Cements Type III: Liners and Bases Type IV: Pits and Fissure Sealants Type V: Orthodontic Cementation Type VI – GIC is used for core build-up Type VII – Fluoride releasing light-cured GIC Type VIII – GIC for ART Type IX – GIC used for pediatric and older adult restorations

What is glass ionomer cement used for?

Glass ionomer cement (GICs) are widely used in dentistry for their unique and beneficial properties. One of the primary uses of GICs is in restorative dentistry, where they serve as filling materials for cavities. 

Restorative Material

GICs are particularly advantageous for use in cavities in areas not subjected to heavy chewing forces, such as the cervical and root surfaces of teeth. Their ability to chemically bond to both enamel and dentin and less moisture sensitivity provides a durable and reliable seal, reducing the likelihood of secondary caries.

Pulp Protection

Additionally, GICs are commonly utilized for their fluoride-releasing properties. This fluoride release helps in the remineralization of the surrounding tooth structure and contributes to the prevention of further dental decay. 

This makes GICs an excellent choice for patients with high caries risk, such as children and the elderly. The biocompatibility of GICs also makes them suitable for use as liners or bases under other restorative materials, providing thermal insulation and reducing post-operative sensitivity.

Pits & Fissure Sealant

Deep pits and fissures are the perfect haven for caries-causing microorganisms to grow: they’re difficult to clean, moist, and the enamel in this portion is thin. Using GICs as pits and fissure sealant is helpful as this dental material releases fluoride to aid in remineralization of the enamel and it effectively seals the pits and fissures and allows a surface that is more cleansable for patients.  

Luting Agent

GICs are used in orthodontics for cementing brackets and bands due to their adhesive qualities and ease of use. Their ability to bond to tooth surfaces without extensive preparation and their relatively quick setting time make them a practical choice for orthodontic applications. Overall, glass ionomer cements play a crucial role in modern dentistry, offering a versatile and effective solution for various dental treatments.

What are the three types of glass ionomer cement?

Glass ionomer cements (GICs) are a versatile class of dental materials used for a variety of restorative procedures. They are classified into three main types based on their composition and clinical use: Type I, Type II, and Type III.

Type I: Luting Cements

Type I GICs, also known as luting cements, are primarily used for the cementation of crowns, bridges, and orthodontic brackets. These cements are designed to provide a strong bond to both enamel and dentin, ensuring stable placement of dental appliances. Their adhesive properties, combined with their ability to release fluoride, help in preventing secondary caries around the margins of the restorations.

Type II: Restorative Cements

Type II GICs are restorative cements, which are employed for direct restorations such as fillings in cavities. They come in two subcategories: aesthetic and reinforced. Aesthetic Type II GICs are used in areas where the appearance is crucial, such as in the restoration of anterior teeth. Reinforced Type II GICs, on the other hand, have enhanced mechanical properties making them suitable for stress-bearing areas like posterior teeth. These cements are appreciated for their unique ability to chemically bond to tooth structure and release fluoride over time, which aids in the prevention of recurrent decay.

Type III: Liners and Bases

Type III GICs are used as liners and bases under other restorative materials or as pit and fissure sealants. These cements are designed to provide a protective barrier between the pulp and the restorative material, reducing sensitivity and promoting the health of the underlying tooth structure. Additionally, their fluoride-releasing capability contributes to the long-term prevention of caries, making them an important component in preventive dentistry.

Other types of GIC: 

• Type IV: Pits and Fissure Sealants
• Type V: Orthodontic Cementation
• Type VI – GIC is used for core build-up
• Type VII – Fluoride releasing light-cured GIC
• Type VIII – GIC for ART
• Type IX – GIC used for pediatric and older adult restorations

How to manipulate GIC?

Click on this link to watch the whole video on how to properly manipulate GIC: https://youtu.be/f32gTgTNqTU

The manipulation of Glass Ionomer Cements depends on the instructions of the manufacturer. However, the usual way to use restorative cements is through this way:

1. Dispense 1 scoop of the powder component and 1 drop of the liquid component, or whatever the manufacturer instructs in a mixing pad or a cold glass slab, if you prefer a longer working time. 
2. Divide the powder into 2 increments.
3. With the use of a plastic or agate spatula, incorporate 1 increment to the liquid component, using a folding motion for 15 seconds. 
4. Add the rest of the increment to adjust the consistency.
5. Once the mixture has a glossy and dough-like consistency, it can now be placed into the cavity. 

What are the disadvantages of glass ionomer cement?

Glass ionomer cement (GIC) is widely used in dentistry due to its beneficial properties like fluoride release and chemical bonding to the tooth structure. However, it also has several disadvantages that must be considered. 

Poor Mechanical Properties

One of the primary drawbacks is its relatively low mechanical strength. Compared to other restorative materials like composite resins or amalgam, GIC is more prone to wear and fracture, especially in areas subjected to high masticatory forces such as the occlusal surfaces of molars.

Solubility

Another disadvantage is its initial solubility. When first placed, GIC is more susceptible to moisture contamination, which can compromise the setting reaction and reduce the longevity of the restoration. This necessitates careful handling and sometimes the use of protective coatings to ensure optimal performance during the initial setting phase. 

Inferior Esthetics

Additionally, the esthetic properties of GIC are often inferior to those of composite resins. While advancements have been made to improve its appearance, the material generally lacks the translucency and color-matching capabilities of composites, making it less desirable for use in highly visible areas of the mouth.

Shrinkage and Microcracks

Lastly, GIC can be sensitive to dehydration. If it loses moisture too quickly, it can lead to shrinkage and microcracking, affecting the integrity of the restoration (Davidovic, 2019). Therefore, maintaining a balanced hydration level is crucial during the setting process. 

Despite these disadvantages, GIC remains a valuable material in many clinical situations, particularly for patients at high risk of caries due to its fluoride-releasing property, which can help in remineralizing adjacent tooth structures.

In Conclusion

Just like other dental materials in the market, Glass Ionomer Cements offer a fair share of advantages and disadvantages to our patients. It is in our professional judgement as to what restorable material would be the best option for their condition. 

References:

Davidovic, Lado & Stojanovic, Nikola & Krunić, Jelena & Zivkovic, Slavoljub. (2013). Scanning electron microscopy analysis of adhesive bond of glass-ionomer cement restorations. Stomatoloski glasnik Srbije. 60. 85-92. 10.2298/SGS1302085D. 

Sikka N, Brizuela M. Glass Ionomer Cement. [Updated 2024 Mar 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK582145/