Is Resin-Modified Glass Ionomer Cement (RMGIC) more moisture-tolerant than traditional Glass Ionomer Cement (GIC)?

Moisture Tolerance: RMGIC vs GIC

Traditional Glass Ionomer Cement (GIC) is inherently more moisture-tolerant than Resin-Modified Glass Ionomer Cement (RMGIC), making GIC the preferred choice when moisture control is challenging.

Key Material Properties

Traditional GIC (Conventional Glass Ionomer)

• GIC tolerates moisture during setting because it undergoes an acid-base reaction that is not disrupted by water contamination 1
• The material can even benefit from slight moisture during the initial setting phase, as it prevents desiccation 1
• This makes GIC particularly practical for managing cavitated lesions in young, uncooperative children and in circumstances where traditional moisture control is not possible 2

RMGIC (Resin-Modified Glass Ionomer)

• RMGIC is moisture-sensitive and requires dry surfaces for proper adhesion, similar to resin-based materials 3
• The resin component undergoes light-activated polymerization that is compromised by moisture contamination 4
• Moisture will prevent proper adhesion and compromise the restoration's longevity 3

Clinical Performance Comparison

Longevity Data

• RMGIC demonstrates superior longevity with a 50% survival time of 55 months compared to 48 months for GIC in primary teeth (p = 0.01) 1
• At 8 years, 37% of RMGIC restorations required repair/replacement versus 44% of GIC restorations 1
• RMGIC exhibited 100% survival at one year in modified cavity preparations versus 90% for conventional preparations 5

Clinical Success Rates

• RMGIC showed 100% success rate at 6 months using ART criteria, compared to 92.4% for GIC (p = 0.009) 4
• In Class V restorations, RMGIC (Fuji II LC) demonstrated significantly higher overall success rates compared to GIC (Fuji IX) at 2.5-3.5 years (p = 0.0104) 6
• RMGIC gave the best results at one year with the highest percentage of intact marginal integrity 7

Clinical Decision Algorithm

When moisture control is compromised:

• Use traditional GIC for interim therapeutic restorations in young, uncooperative children 2
• GIC is the material of choice when placement of traditional restorations is not possible due to patient cooperation or field isolation issues 2

When adequate moisture control is achievable:

• RMGIC should be preferred for Class II restorations in primary dentition due to enhanced longevity 1
• RMGIC is suitable for Class I cavities, particularly with beveled preparations 5
• Ensure surfaces are completely dry before applying RMGIC to prevent adhesive failure 3

For specific cavity types:

• Class III/V restorations should be made in GIC due to enhanced longevity in these preparations 1
• Class II restorations benefit from RMGIC when moisture control is adequate 1

Common Pitfalls to Avoid

• Do not use RMGIC in situations where moisture contamination is likely, as this will compromise the resin polymerization and lead to early failure 3, 4
• Avoid assuming RMGIC's superior mechanical properties translate to better performance in all clinical scenarios—moisture tolerance must be the primary consideration 1
• Do not overlook GIC's practical advantages in field settings where dental therapists and hygienists provide care without optimal moisture control 2

Cariostatic Effects

Both materials demonstrate similar cariostatic effects on restored teeth and adjacent surfaces, with no significant difference in the 75% survival time (35 months for both materials, p = 0.37) 1. This means the choice between materials should be based primarily on moisture control capability and cavity type rather than caries prevention alone.