Placing high-viscosity glass-ionomers as sealants and posterior load bearing tooth restorations may not lead to clinically inferior results.
Johannesburg, Gauteng (PRWEB) June 17, 2014
For some time the dental community has operated under the assumption that high-viscosity glass-ionomers are inferior to the current clinical gold standard when sealing pit and fissures to prevent dental caries and when placing restorations in posterior load bearing teeth.
This popularly held notion could be largely attributed to an unsubstantiated belief in the poor performance of glass-ionomers for both clinical indications. Instead, the vast majority of modern dental practitioners tend to prefer the application of resin-based materials when sealing pit and fissures due to its established higher material retention rate, while silver amalgam and resin composites are the generally preferred materials for placing posterior tooth restorations.
In an effort to appraise the current clinical evidence regarding the merits of glass-ionomers as tooth restorations and sealants, the SYSTEM Initiative of the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, has conducted a number of systematic reviews of clinical trials while simultaneously investigating the accuracy of comparison results from longitudinal studies with that from randomised control trials (RCT).
SYSTEM’s results show that no clinical evidence exists to substantiate the belief that high-viscosity glass-ionomers are inferior to the current gold standard when placing restorations in posterior load bearing teeth and when sealing pit and fissure to prevent the development of tooth caries.
SYSTEM’s investigations further show that there is very poor agreement between results from clinical uncontrolled longitudinal studies and RCTs. While comparisons within an RCT would show that the number of treatment failures of two treatments is similar, the comparison between different longitudinal studies would erroneously show a higher failure rate of one type of treatment above the other. Accordingly, expert reviews would mistakenly recommend the merit of placing one type of tooth restorations above that of another.
Largely for this very reason, high-viscosity glass-ionomer restorations have been regarded as clinically inferior to that of silver amalgam in dental practice. When the results of all longitudinal studies, published during the last ten years, for high-viscosity glass-ionomer restorations were compared with that of amalgam restorations placed in posterior load bearing teeth a largely higher performance for amalgam was found. However, no difference between high-viscosity glass-ionomer and silver amalgam was found in all RCTs, published during the same time period.
A similar systematic review of available literature also indicated a deficiency in clinical evidence to support the idea that resin based fissure sealants protect better against tooth caries than glass-ionomer based sealants. The review included a literature search in global databases, such as PubMed/Medline and the Cochrane library, open-access data sources comprising of Biomed Central; the Directory for Open Access Journals and Science Direct. In total, 16 clinical trials were accepted as evidence, including the investigation of more than 7 000 placed fissure sealants. The outcome suggested no statistically significant difference in the caries failure rate between glass-ionomer and resin sealed teeth after follow-up periods ranging from six months to seven years. A subsequent investigation to the original systematic review in 2008 was conducted in 2013 and established that its conclusion remains current.
In summary, SYSTEM’s findings suggest that placing high-viscosity glass-ionomers as sealants and tooth restorations does not lead to clinically inferior results.
The published full reports of the findings are available online:
 Mickenautsch S, Yengopal V. Failure rate of high-viscosity GIC based ART compared to that of conventional amalgam restorations - evidence from a systematic review update. S Afr Dent J 2012; 67: 329-31. [http://www.ncbi.nlm.nih.gov/pubmed/23951787
 Mickenautsch S, Yengopal V. Direct contra naïve-indirect comparison of clinical failure rates between high-viscosity GIC and conventional amalgam restorations. An empirical study. PLOS One 2013; 8: e78397. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0078397
 Mickenautsch S, Yengopal V. Caries-preventive effect of glass ionomer and resin-based fissure sealants on permanent teeth: An update of systematic review evidence. BMC Res Notes 2011; 4: 22. http://www.biomedcentral.com/1756-0500/4/22
 Mickenautsch S, Yengopal V. The modified Ottawa method to establish the update need of a systematic review: Glass-ionomer versus resin sealants for caries prevention. J Appl Oral Sci 2013; 21: 482-9. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3881834/