there appears to be no valid evidence that placing silver amalgam restorations is clincially superior to placing high-viscosity glass-ionomer restorations in load bearing posterior cavities of permanent teeth
Johannesburg, Gauteng (PRWEB) May 15, 2014
Despite its trust and reliance on scientifically sound methods in clinical research and practice, a large part of the global dental community currently operates on an unsupported conception regarding the placement of load bearing or multiple surface cavity restorations in posterior teeth.
For several decades many practicing dentists have accepted the consensus that silver amalgam is clinically superior to glass-ionomers when placing restorations in posterior teeth despite a distinct lack in valid clinical evidence to support this belief.
In an effort to appraise the current clinical evidence, the SYSTEM Initiative of the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, has conducted a systematic review of randomised control trials and a meta-epidemiological study to this topic.
This scientifically focused analysis incorporated a systematic literature search in 17 global and regional databases, databases for open access journals and ‘grey’ literature. In addition to searching the global databases PubMed/Medline and the Cochrane library, SYSTEM searched additional regional English databases comprised of the scientific dental literature from Africa, Europe, India and North America, whilst regional non-English databases comprised of the dental literature from China and Latin-speaking American countries.
In total, 38 controlled clinical trials were accepted as evidence, comprising the investigation of more than 10,000 placed tooth restorations. The outcome shows that amalgam cannot be regarded as superior to new generation, high viscous glass-ionomers fillings, due to a lack of clinically meaningful differences in both restoration types’ failure rates beyond the play of chance.
The results of SYSTEM’s meta-epidemiological study shows that statements concerning amalgam’s superiority are based on incorrect statistical comparison methods. Such methods continue to include and rely on the common naïve-indirect comparison of restoration failure rates from uncontrolled clinical longitudinal studies.
Simply put, the traditional argument against the use of glass-ionomers in modern dentistry is based on the incorrect assumption that results from unrelated clinical trials with differing clinical settings and patient groups can be directly compared to one another. Instead, statements concerning the merits of clinical interventions should rest on the direct comparison of competing treatment options via randomised control trials.
High-viscosity glass-ionomer restorations do not require provision of macro-retention by high-speed drilling, thus they offer the dental profession a more patient friendly approach for placing tooth restorations. Placing glass-ionomer restorations also reduces the likelihood of a repeated restoration cycle, because repair of failed restorations does not require the removal of remaining filling material from the tooth cavity.
The new findings suggest no valid evidence that placing silver amalgam restorations is clincially superior to placing high-viscosity glass-ionomer restorations in load bearing posterior cavities of permanent teeth.
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.
(Text of the full systematic review report:
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.