GC America believes in the importance of informing dentists about the evidence available on Minimally Invasive Dentistry topics so they can make scientifically sound choices in the treatment of their patients. In the research-clinical application jigsaw puzzle, it is essential to make all the pieces fit in order to see the whole picture.

Systematic review with meta-analysis

AIM: To quantitatively appraise the current evidence regarding the caries-prevention effect of resin-modified glass ionomer cement (RM-GIC) fissure sealants in comparison to that of resin-based fissure sealants.

METHODS: 8 Anglophone databases and 2 Lusophone databases were searched until 15 April 2009, using a pre- determined search strategy. Clinical trials were considered for inclusion if their titles/abstracts were relevant to the topic, published in English, Portuguese or Spanish and had a two-arm longitudinal study design. The outcome measure of the caries-preventive effect was caries absence on sealed teeth. Two reviewers independently extracted data from the accepted articles in order to complete a 2×2 table for meta-analysis. The unit of interest was the tooth, and the number of caries-free teeth (n) at the end of each time interval (6, 12 and 24 months) was compared against the total number of evaluated teeth (N).

STATISTICS: Datasets were assessed for their clinical and methodological heterogeneity, following Cochrane guidelines, and only homogeneous datasets were combined for meta-analysis, using a random effects model (RevMan 4.2). Differences in the caries-preventive effect were computed on the basis of the combined Relative Risk (RR) with 95% confidence interval (CI).

RESULTS: Of the 212 articles identified, only 6 trials were included. From these, 19 separate datasets were extracted. For the pooled data, equivalent caries-preventive effects were observed at 6 months (RR= 0.98, 95% CI 0.95- 1.00; p = 0.08); 12 months (RR=1.00, 95% CI 0.96-1.04, p = 0.99) and 24 months (RR=1.01, 95% CI 0.84-1.21, p = 0.91). The 36-month data (not pooled) favored resin-based sealants (RR 0.93, 95% CI 0.88-0.97, p = 0.002).

CONCLUSIONS: This meta-analysis found no conclusive evidence that either material was superior to the other in preventing dental caries.
European Archives of Paediatric Dentistry, official journal of the European Academy of Paediatric Dentistry (2010) Volume: 11, Issue: 1, Pages: 18-25

The academic perspective: Dr Steffen Mickenautsch, University of the Witwatersrand, South Africa

What were the main reasons for reviewing this particular area of dental materials?
Steffen Mickenautsch: Resin is still considered to be the material of choice, worldwide, to caries-protect pits and fissures. This begs the question: Why? Is this so because we have overwhelming scientific evidence for its preference? Or overwhelming evidence in the sense that it sweeps any other possible materials asunder? Or is it just because of tradition, because we do not know the merits of other materials, or finally simply: because we have been told so in dental school? It is always interesting (and beneficial to the heart and mind) to find out the truth of things and that is why we embarked on an intensive systematic review programme that also included the comparison of the caries preventive effect between resin-based and resin-modified glass ionomer cement (RM-GIC) based fissure sealants.

What criteria did the articles you selected meet and why is this important?
Steffen Mickenautsch: We aimed to identify all evidence to this topic from all different sources, corners of the world and from as many languages as possible. We did that in a systematic format and from what we found we selected studies that were relevant, i.e. compared the two types of material with each other. Then these studies needed to have been randomized in some way. Randomization assures that patients whose teeth were sealed with either resin or RM-GIC do not substantially differ, thus are comparable. Studies who do not use randomization, cannot tell whether any observed results, e.g. that one material performed better than the other, were due to the material and not due to other factors (like one group of patients may simply had better oral hygiene or used fluoride and thus had less caries activity than the other, regardless what materials was used).

What should the general dental practitioner understand about this particular review?
Steffen Mickenautsch: The general dentist in her/his daily dental practice should have the knowledge that there is simply no scientific evidence that says that resin protects pits and fissures better against caries than RM-GIC.

How should general dentists apply the conclusion of this review to their daily practise of dentistry?
Steffen Mickenautsch: The application of this knowledge would be that if a dentist finds resin not to be a favorable choice to use as fissure sealant, perhaps for reasons of moisture control, material handling, material availability, costs, a personal reason, or reason stated by the patient etc., then RM-GIC can provide a good alternative.

How does this review contribute to the body of evidence on this topic in dentistry?
Steffen Mickenautsch: This is the very first quantitative systematic review and thus offers the best source of current scientific evidence to this topic. It’s the best, simply because: it first and foremost employed a comprehensive systematic sweep through all possible scientific and non-scientific sources of evidence available to answer a particular question. From everything that we found, we selected the best evidence in line with commonly accepted criteria and then we quantified this evidence, using meta-analysis, in order to provide a precise and well weighted answer to whether resin is better than RM-GIC in preventing caries or not. The result showed that it’s not.

Is more evidence needed on this topic? If so, what gaps are there in the research that has been done thus far on it?

Steffen Mickenautsch: From an academic point of view there is always need for more evidence – even just for the purpose to confirm the current state of evidence. It is recommended that future studies to this topic should report in much more detail on their randomization methods, which would remove any last academic shred of doubt. Our team is committed to continuously update current systematic review evidence – to this topic perhaps in about 2-3 years’ time. For now the current evidence from our systematic review is as good as it can get.

Clinician comments: Dr Geoff Knight, private dentist based in Australia

For how long have you been using glass ionomer cements in practice – and what motivated your decision to use them in the first place?
Geoff Knight: I met Dr Jurgen Eberlein at a dental seminar in Melbourne in the late 1970s. He was then with ESPE and gave me some samples of Ketac Fill to use in my practice. I was concerned about the recurrent caries I was seeing with composite resin and was impressed with the anti caries properties, low interface stress and ease of handling and I found myself using it for more and more clinical applications.

What is your preferred protocol for fissure sealing and what materials do you prefer to use for this?
Geoff Knight: I fissure seal with auto-cure glass ionomer cement because the material has relatively good wear resistance, releases abundant fluoride to convert carbonated apatite into fluorapatite and is a semi permeable to enable phosphate and calcium ions in towards the enamel and hydrogen ions to move outwards. Furthermore when the GIC is placed on the enamel surface it has a low pH that dissolves the outer surface of carbonated apatite enamel crystals so as to enable the formation of fluorapatite crystals after the GIC sets and the pH returns to neutral.

I am unaware of any tooth that I sealed with auto-cure glass ionomer cement ever developing a carious lesion beneath the seal. My current gem is Colgate Neutra fluor 5000 plus tooth paste. When patients brush without rinsing twice daily it prevents caries and significantly improves periodontal health.

Before reading the meta-analysis, what was your opinion of resin-modified glass ionomer cements versus resin-based materials as fissure sealants?
Geoff Knight: Resin fissure sealants prevent carbonated apatite from maturing into fluorapatite and have no place in MID. Resin modified glass ionomer cements enable the transfer of carbonated apatite into fluorapatite but do not wear as well as auto-cure GICs.

As a busy clinician, how do you keep yourself updated on developments in clinical evidence in dentistry, particularly in MID?
Geoff Knight: Read the literature, use Google and look at focused resources such as Dental Outlook here in Australia.

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