Systematic reviews reveal the continued evolution of dental materials
Results from a recent systematic review suggest high-viscosity glass-ionomer cement (GIC) as safe and economical long-term tooth restorative system in conventional stress bearing Class I and in non-stress bearing Class II and Class V situation. High-viscosity GIC may also be acceptable in Class II stress bearing situations, as long as the isthmus is less than half of the intercuspal distance as stated in the manufacturer’s instruction of use.
Systematic reviews, often including meta-analysis as statistical method, provide the highest form of clinical knowledge in terms of achieving internal validity of results. One systematic review appraised the current clinical evidence regarding the use of high-viscosity GIC for longterm Class I, II and V tooth restorations placed in permanent teeth (1). This systematic review included 14 clinical studies, providing a total of 27 separate study results and concluded as follows:
- Most of the 27 results show no significant statistical difference between the success rate of high viscosity GIC restoration and amalgam for treatment of the same clinical indications
- One of the 27 results show that high-viscosity GIC restorations in posterior class V cavities of permanent teeth had a 28% higher chance to be more successful than amalgam after 6.3 years
- Two of the 27 results indicate that high-viscosity GIC restorations in posterior class I cavities of permanent teeth have a 6% higher chance after 2.3 years and a 9% higher chance after 4.3 years of being more successful than amalgam
- One of the 27 results show that high-viscosity GIC restorations in posterior class II cavities of permanent teeth have a 61% higher chance of being rated more successful than amalgam (this result requires further confirmation)
- None of the 27 results indicate high-viscosity GICs being inferior to amalgam in clinic
These results show that high-viscosity GIC is not inferior in comparison to traditional amalgam restorations under similar clinical conditions. In addition, two further systematic reviews revealed the following evidence:
* Tooth margins of single-surface GIC restorations in permanent teeth had significantly less carious lesions after 6 years than on amalgam restorations (2)
* A significantly higher fluoride release (p<0.05) of GIC than from compomers (3)
Further advances have revealed that a resin coating over a GIC restoration may increase its fracture toughness (4) and reduce microleakage (5). This resin layer may also not completely hinder the fluoride release activated by the GIC and thus its external anti-cariogenic effects within the oral cavity (6).
Scientific journal articles for further reading:
1. Systematic review of clinical trials by Mickenautsch et al., Clinical Oral Investigation 2010; v14:pp233-240.
2. Systematic review of clinical trials by Mickenautsch et al., European Journal of Paediatric Dentistry 2009; v10: pp41-46.
3. Systematic review of trials by Oliveira et al., Journal of Minimum Intervention in Dentistry 2010; v3: p23 – abstract 023.
4. Investigation of dental materials by Bagheri et al., American Journal of Dentistry 2010; v23: pp142-146.
5. Investigation of dental materials by Magni et al., Journal of Dentistry 2008; v36: pp885-891.
6. Investigation of dental materials by Mazzaoui et al., Dental Materials 2000; v16: pp166-171.