Caries-preventive effect of resin-modified glass-ionomer cement (RM-GIC) versus composite resin: a quantitative systematic review.
Abstract: AIM: To determine whether resin-modified glass-ionomer cement (RM-GIC), when compared with composite resins (CR), offers a significant caries-preventive effect. STUDY DESIGN: Quantitative systematic review. METHODS: Five databases were searched until 29 July 2010. Inclusion criteria were: relevant to review question related to orthodontic or restorative treatment; published in English; prospective clinical 2-arm study. Exclusion criteria were: no computable data reported; study groups not followed up in the same way. References of included articles were checked. The outcome measure was absence of carious lesions. Dichotomous datasets for both groups were extracted from accepted trials. Trials were assessed for selection-, detection/performance, attrition and publication bias. RESULTS: Of the 11 trials included, 6 were accepted and 24 datasets extracted; 17 datasets showed no difference after 4 weeks to >25 months. There were 7 datasets that favoured (p < 0.05) RM-GIC after 12-24 months. The results are limited by risk of selection-, detection/performance bias and attrition bias. Risk of publication bias was identified. CONCLUSIONS: The overall results showed either no difference between the materials, or indicated that RM-GIC has a superior caries-preventive effect. The clinical meaning of this result remains uncertain due to risk of bias. High-quality randomised control trials are needed in order to answer the review question conclusively.

Key words: resin-modified glass ionomers, composite resin, caries, systematic review
Article Type: Report
Subject: Dental caries (Care and treatment)
Dental caries (Research)
Dental adhesives (Health aspects)
Dental adhesives (Comparative analysis)
Dental glass ionomer cements (Health aspects)
Dental glass ionomer cements (Comparative analysis)
Authors: Yengopal, V.
Mickenautsch, S.
Pub Date: 02/01/2011
Publication: Name: European Archives of Paediatric Dentistry Publisher: European Academy of Paediatric Dentistry Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2011 European Academy of Paediatric Dentistry ISSN: 1818-6300
Issue: Date: Feb, 2011 Source Volume: 12 Source Issue: 1
Topic: Event Code: 310 Science & research
Product: Product Code: 3843075 Dental Adhesives NAICS Code: 339114 Dental Equipment and Supplies Manufacturing SIC Code: 3843 Dental equipment and supplies
Geographic: Geographic Scope: South Africa Geographic Code: 6SOUT South Africa
Accession Number: 277106720
Full Text: Introduction

The presence of secondary or recurrent caries is a common reason for replacing restorations and is often observed after bonding of brackets on the tooth surface during orthodontic treatment. An ideal dental material would have, as one of its properties, the ability to prevent demineralisation and/or promote remineralisation [Mjor and Toffenetti, 2000]. Studies have shown that restoration replacement accounts for 50-70% of the dental care provided in some settings [Donly et al., 1999]. As ionic fluoride in the water supply [McDonagh et al., 2000] and in other vehicles, such as toothpaste [Twetman et al., 2003], has been shown to reduce the incidence of caries at the population level, considerable attention has been focused on fluoride-containing restorative materials.

The earliest fluoride-releasing restorative material was silicate cement (now superseded). Anecdotal evidence of its caries-preventive effect was related to the paucity of reports of secondary caries seen in association with silicate cement despite its high intra-oral solubility [Ewoldson and Herwig, 1998]. This observation led to the inclusion of fluoride into restorative materials such as amalgam and resin-based materials, although published evidence of an anti-caries effect was not observed [Wiegand et al., 2007].

Light-cured resin-modified glass-ionomer cements (RM-GIC) were developed as restorative materials, to address the shortcomings of conventional glass-ionomer restorative materials (C-GICs) [Nagamine et al., 1997] which, owing to their ability to leach fluoride into the surrounding tooth structure, significantly influenced the demineralisation-remineralisation cycle and thus produced an anti-caries effect. This effect was observed at the margins of the C-GIC fillings and on adjacent interproximal carious lesions [Jang et al., 2001]. By comparison with C-GICs, RM-GICs were found to have advantages, such as more resistance to early contamination by moisture, better mechanical properties, less microleakage and better bonding to dentine [Nagamine et al., 1997].

Composite resins (CR) are regarded as the "gold standard" in terms of aesthetic restorative materials and their widespread use can be ascribed to factors such as ease of manipulation and excellent aesthetics [Okida et al., 2008]. CR is also commonly used for the bonding of brackets onto tooth surfaces during orthodontic treatment. The addition of fluoride ions into CR [Torii et al., 2001] has shown promise both in laboratory [Park and Kim, 1997; Wilson and Donly, 2001] and clinical studies [Andersson-Wenckert and Sunnegardh-Gronberg, 2006].

This systematic review sought to quantitatively answer the question as to whether RM-GIC, when compared with CR, offers a more significant caries-preventive effect and to review the validity of the available evidence with regard to risk of bias.

Materials and methods

Data collection. Five Anglophone databases: Biomed Central, Cochrane Library, Directory of Open Access Journals, PubMed and Science-Direct were systematically searched for articles reporting on clinical trials up to 29 July 2010. Two strings of MeSH and text search terms, with Boolean operators:

((('Tooth Remineralisation' [Mesh] OR 'Tooth Demineralisation' [Mesh])) AND 'Glass Ionomer Cements' [Mesh]) AND 'Composite Resins' [Mesh], as well as:

((('Dental Caries' [Mesh] OR 'Dental Caries Susceptibility' [Mesh] OR 'Root Caries' [Mesh])) AND 'Glass Ionomer Cements' [Mesh]) AND 'Composite Resins' [Mesh], were used in searching the databases. Articles from the search results were selected for review on the basis of their compliance with the inclusion criteria:

* Relevant to review question related to orthodontic or restorative treatment;

* Published in English;

* Prospective clinical 2--(or more) arm study.

Where only a relevant title without a listed abstract was available, a full copy of the article was assessed for inclusion. References of included articles were checked for additional studies suitable for review.

Article review. Only articles that complied with the inclusion criteria were reviewed further. Full copies of articles were reviewed independently by two reviewers (VY and SM). Disagreements between reviewers were resolved by discussion and consensus.

Articles were excluded if:

* No computable data was reported;

* Subjects of both groups were not followed up in the same way.

(For example, the criteria used to assess the absence of caries in a test group should be exactly the same as in the control group. This might sometimes vary, especially in multi-centre trials, where some examiners may use a combination of clinical, visual and radiological aids to check for caries at margins at one centre whilst the other centre may use only visual inspection for caries diagnosis. This lack of consistency in the diagnostic criteria is a significant source of bias).

Data extraction from accepted trials. The outcome measure was carious lesion absence. Two reviewers (VY and SM) independently extracted data from the accepted articles. Individual dichotomous datasets for the control- and test group were extracted from each trial. Where possible, missing data were calculated from information given in the text or tables. In addition, in order to obtain missing information, authors of trials were contacted. Disagreements between reviewers during data extraction were resolved through discussion and consensus. It was anticipated that some of the trials eligible for inclusion would be split-mouth in design (quasi-randomised trials). The split-mouth study design is commonly used in dentistry to test interventions and has the advantage of enabling an individual to serve as both subject and control. In this study design one or more pairs of teeth (e.g. primary molars) form the unit of randomisation. These pairs are, strictly speaking, not independent and should be analysed as 'paired data' on a per-patient basis. However, as in other similar systematic reviews [Mickenautsch et al., 2009], in order to prevent exclusion of data, split-mouth trials were included and the pairs were analysed independently.

Quality of studies and assessment of potential bias risk. Criteria for quality assessment of trials are listed in Table 1. Quality assessment of accepted trials was undertaken on the basis of availability of evidence indicating successful prevention of selection- and detection/performance bias from the start to end of each trial. If a trial merely reported that randomisation was conducted, reported only the name of the randomisation method used or included a detailed description of the randomisation process without providing any evidence that randomisation was indeed effective throughout the trial, this was regarded as inadequate.

Sensitivity analysis was done, using the RevMan Version 4.2 statistical software of The Nordic Cochrane Centre, The Cochrane Collaboration (Copenhagen; 2003), in order to investigate potential attrition bias risk in trials.

To investigate publication bias, a funnel plot was generated, using the datasets from the included clinical trials. The standard error (SE) of the mean differences was plotted on the Y-axis, and the log of the Relative Risk (RR) on the X-axis, using MIX Version 1.7 meta-analysis software [Bax et al., 2006]. In addition, Egger's linear regression method [Egger et al., 1997] was used to calculate an intercept with a 95% Confidence Interval (CI), with statistical significance set at a = 0.05.

Statistical analysis. RevMan Version 4.2 statistical software from The Nordic Cochrane Centre, The Cochrane Collaboration (Copenhagen, 2003) was used to analyse extracted dichotomous datasets. Differences in treatment groups were computed on the basis of Relative Risk (RR), with 95% confidence intervals (CI).

Meta-analysis was considered for datasets only if they complied with criteria for clinical homogeneity. Datasets were considered clinically homogeneous if the CR material contained fluoride and the datasets covered the same type of dentition: type of teeth; study length; type of evaluation method; external fluoride exposure; type of treatment (orthodontic or restorative).

Results

Literature search. Figure 1 provides information on the number of articles identified through the search strategy. From 11 articles considered for possible inclusion, 5 were excluded [van Dijken, 2001; Burgess et al., 2004; Kotsanos and Dionysopoulos, 2004; Takeuti et al., 2007; Paradella et al., 2008]. Table 2 provides reasons for the exclusion of these trials. Thus, the results presented were obtained from 6 trials, all of which were split-mouth in design. [Kilpatrick et al., 1996; Chung et al., 1998; Garworski et al., 1999; Fuks et al., 2000; McComb et al., 2002; Andersson-Wenckert and Sunnegardh-Gronberg, 2006].

Table 3 describes the characteristics of the included trials and the datasets derived from the results presented in each of them. The Chung et al. [1998] and Gaworski et al. [1999] randomised clinical trials compared RM-GIC and CR material when used for orthodontic bracket bonding in permanent teeth [Chung et al., 1998; Gaworski et al., 1999]. Both papers regarded the absence of signs of decalcification as indicating caries absence.

Dataset extraction and analysis. There were 24 dichotomous datasets extracted from the 6 accepted trials; 17 of them showed no difference between the two materials after test periods lasting from 4 weeks to >25 months (Table 4). Another 7 dichotomous datasets (DS 06, 08, 09, 12-14, 16) were extracted from two trials [McComb et al., 2002; Andersson-Wenckert and Sunnegardh-Gronberg, 2006] and showed statistically significant results (p < 0.05) in favour of RM-GIC after 12 to 24 months. One of these datasets with statistically significant results (DS 06) was derived from one trial including CR with fluoride [Andersson-Wenckert and Sunnegardh-Gronberg, 2006]. The results indicated that primary teeth restored with RM-GIC would have an 11% higher chance of remaining caries-free on their restoration margins than if they were restored with fluoride-containing CR, after 24 months (DS 06: RR 1.11; 95% CI 1.01-1.23; p = 0.04).

[FIGURE 1 OMITTED]

Results concerning the permanent dentition indicated a 2-3 times higher chance of remaining caries-free on restoration margins for teeth restored with RM-GIC, than for teeth restored with CR (not containing fluoride) without external fluoride exposure, after 24 months (DS 14: RR 2.63; 95% CI 1.13-6.09; p = 0.02), and with external fluoride exposure, after 18 months (DS 16: RR 2.10; 95% CI 1.04-4.24; p = 0.04) [McComb et al., 2002].

Clinical heterogeneity in terms of evaluation criteria, evaluation method, type of dentition, as well as fluoride exposure and study period, was observed for all datasets and no meta-analysis was attempted.

Quality assessment of trials and risk of bias

Selection-, Detection/Performance bias risk. The results of the quality assessment regarding selection- and detection/performance bias are shown in Table 5. None of the accepted trials reported sufficient details of any randomisation process that had indeed given each patient the same chance to be allocated to either the RM-GIC or the CR group and to ensure that direct observation and prediction of the allocation sequences was successfully prevented. Moreover, none of the accepted trials had mentioned baseline data collected before randomisation, and subsequently reported, for both treatment groups. Nor had they statistically compared this data between groups, and none fulfilled the criteria (Table 1) related to successful blinding/masking of patients, operators and trial evaluators.

Attrition bias risk. Sensitivity analysis was used in computing all datasets, under the assumption that either:

* All teeth lost to follow-up developed carious lesions;

* None of the teeth lost to follow-up developed carious lesions.

The numbers of teeth lost to follow-up per dataset are shown in Table 3. The results of neither situation changed the conclusions for most of the datasets. However, a possible risk of attrition bias was identified in the results of four datasets (DS 06, 08-10) extracted from two trials [McComb et al., 2002; Andersson-Wenckert and Sunnegardh-Gronberg, 2006]. Under the assumption that all teeth lost to follow-up would have developed caries, the results of three datasets (DS 06, 08, 09) would not be statistically significantly in favour of RM-GIC: DS 06--RR 1.11 (95% CI: 0.90-1.38; p = 0.33); DS 08--RR 1.14 (95% CI: 0.86-1.50; p = 0.36) and DS 09--RR 1.13 (95% CI: 0.66-1.91; p = 0.66). The results of one dataset (DS 10) would be statistically significantly in favour of RM-GIC under the assumption that all teeth lost to follow-up would not have developed caries (RR 1.19 - 95% CI: 1.03-1.37; p = 0.02).

Publication bias risk. Publication bias was investigated, using one funnel plot (Figure 2). The funnel plot showed an uneven distribution that did suggest publication bias. Egger's linear regression method for the same datasets showed an intercept of 1.35 (95% CI: 0.49-2.21; p = 0.004). The regression result was statistically significant in favour of RM-GIC.

Discussion

This systematic review sought to quantitatively answer the question as to whether RM-GIC, when compared with CR, offers a significant caries-preventive effect. Despite an extensive search of the literature, only six articles were included for analysis in this review. A perusal of the Cochrane library, which is regarded as the premier source of systematic reviews, reflects a similar trend, whereby the majority of studies identified for a topic in the search strategy are excluded; mainly because of methodological issues (internal validity) or the manner in which the results (data) are reported /presented. The authors of this review have attempted to address the issue of methodological rigor and data presentation, by setting broad inclusion and exclusion criteria and assessing, in depth, the quality of included trials. This present systematic review did not include trials investigating the caries-preventive effect of RM-GIC versus CR-based fissure sealants, as the authors have already assessed the evidence regarding this topic, in another published review [Yengopal and Mickenautsch, 2010].

[FIGURE 2 OMITTED]

However, other aspects in the methodology of this systematic review might may have contributed to limitations in its results: (i) not all relevant publications were listed in the selected databases; (ii) the chosen search terms may not have been broad enough; (iii) not all relevant publications could be found through the reference check; (iv) not all relevant trials may have been published in English.

The primary outcome of interest in this review was the absence of caries. Whilst visual diagnosis of caries presence/absence could be considered acceptable in the Gaworski et al., [1999] Chung et al. [1998] and McComb et al. [2002] trials (as these were orthodontic or Class V cavity placement, respectively), the lack of any radiographic assessment for caries in the Kilpatrick et al. [1996] trial for detection of interproximal caries limits the validity of these results (see Table 3). In terms of the assessment of the restorations post-treatment, only the Andersson-Wenchert et al. [2006] trial provided details of clinicians undergoing a calibration exercise to ensure consistency of interpretation of the criteria. Thus, the internal validity of the trials was negatively impacted due to the lack of information provided in the five other included trials.

Selection, Detection/Performance bias risk. All of the accepted trials appear to be limited by risk of selection- and detection/performance bias. Bias or systematic error may affect studies, causing either an over- or under-estimation of the treatment effect of an investigated clinical procedure. Overestimation has been observed to be the most common [Chalmers et al., 1977]. Kjaergard et al. [2001] reported a treatment effect overestimation of 48% caused by lack of random sequence allocation and Egger et al. [2003] reported a treatment effect overestimation of 54% and 53% due to lack of allocation concealment and lack of evaluator blinding, respectively.

It has been emphasised that selection bias can only be successfully prevented if the allocation sequence remains truly random and free from potential interference throughout the trial [Berger, 2005; Berger and Alperson, 2009]. Thus, it is important that trials should include an effective process for concealing the random allocation sequence and that by the end of each trial this process has indeed prevented direct observation and prediction of the random sequence allocation [Berger, 2005; Berger and Alperson, 2009]. Quality assessment in terms of the internal validity of trials should therefore be a measure of the result of random sequence allocation and allocation concealment, and not only of it's being recorded.

All trials accepted in this systematic review failed to report not only on evidence of successful sequence allocation and allocation concealment results, but also on necessary details about how sequence allocation and allocation concealment were attempted and whether these measures were successful (Table 5). None of the trials, therefore, provide any guarantee that each patient had an equal chance of being allocated to either treatment group and thus, their allocation may have favoured the outcome of one type of treatment above the other. One measure for testing whether random sequence allocation has been successful is testing whether covariates differ between treatment groups at baseline [Berger, 2005]. None of the articles had included such a test and reported on its outcome.

From the outset, in all trials successful blinding or masking appeared not to have been possible, owing to the obvious differences in clinical appearance between GIC and CR fissure sealants. For that reason, allocation to either treatment group was visible to patients, operators and evaluators. However, the difficulties of successful blinding still carry the danger of detection/performance bias, which may thus have affected the trials' results. Potential knowledge of superiority claims prior to the trial may have led patients to change their oral hygiene habits, operators to place restorations more carefully or evaluators to apply evaluation criteria more subjectively. This in turn may have favoured the outcome of one type of treatment over the other.

Attrition bias risk. Sensitivity analysis may be used in establishing whether missing data could have affected trial outcomes by assuming that the numbers of restoration lost to evaluation were either failures or successes [Higgins and Green, 2006]. Comparison of the analysis results with reported trial outcomes indicates whether different conclusions should be drawn. Sensitivity analysis was conducted for all datasets. The analysis results differed from reported outcomes of four datasets (DS 06, 08-10) extracted from two trials [McComb et al., 2002; Andersson-Wenckert and Sunnegardh-Gronberg, 2006]. How high the caries rate in the teeth lost to evaluation really was remains unknown. Nevertheless, the validity of these datasets can be questioned on grounds of attrition bias. Thus, their results need to be regarded with caution.

Publication bias risk. Publication bias was investigated by generating a funnel plot (Figure 2). Publication bias is present when the results of published research differ from those of all the studies that have been done [Rothstein et al., 2005a]. Funnel plots are scatter graphs showing the sizes of studies on the Y-axis (large studies above; small studies below) and the effect size, observed in these studies, on the X-axis. The effect is that sizes of larger studies tend to cluster near the mean. Small studies have effect sizes that are dispersed across a wider range. Results of both types of study, plotted on a scatter graph, form the shape of an inverted, in absence of publication bias, symmetrical funnel [Rothstein et al., 2005b]. Publication bias results in a concentration of studies on only one side of a funnel plot (asymmetry). Such asymmetry is only created when particular smaller studies showing a larger than average effect are published.

The decision was made to plot results of the 24 extracted dichotomous datasets as units of investigation. These are not all independent from the published trials and this formed a departure from the common application of funnel plots in investigating for publication bias. Despite this departure, the use of datasets (instead of published trials) will also indicate potential publication bias when only datasets that show a larger than average effect are published and other datasets are not. The funnel plot showed an asymmetrical spread of dataset results (Figure 2). As the visual judgement of funnel plots is subjective, an intercept (95% CI) was calculated, using Eggers regression [Egger et al., 1997]. The calculated significant intercept confirmed the observations from the funnel plot. Both suggest that a potential impact of publication bias in favour of RM-GIC exists regarding this topic.

Analysis of results. Most of the dataset results showed no difference between the two types of material: seven showed as favouring RM-GIC [McComb et al., 2002; Andersson-Wenckert and Sunnegardh-Gronberg, 2006;] and none was identified as favouring CR above RM-GIC. However, the clinical meaning of these results remains uncertain, as all trials identified during this systematic review were limited by risk of selection- and detection-/performance bias and, for some datasets, attrition bias. In addition, the risk of publication bias was identified.

All six studies included in this review were split-mouth in design. The split-mouth study design is commonly used in dentistry to test interventions and has the advantage of having an individual serve as both experiment and control. This can increase trial efficiency and, on average, fewer patients are needed [Lesaffre et al., 2007]. However, methodological issues have also been highlighted in recent publications, which must be considered [Lesaffre et al., 2007]. For example, fluoride that is released from RM-GIC over a period of time into the oral cavity can act as confounding factor. Tantbirojin et al., [1997] have shown that RM-GIC provided caries resistance in bovine enamel located at a considerable distance from the margin of cervical restorations. Thus if a test cavity, filled with RM-GIC, is located near a control cavity filled with CR any caries preventive effect of the CR can be positively confounded by the preventive effect of the fluoride released from the nearby RM-GIC. Such confounding effect may generate equivalence in terms of caries absence. Thus, the split-mouth design may be unsuitable and a randomised controlled trial with a parallel group design more appropriate. In addition, split-mouth studies actively exclude patients, i.e. without at least two equal cavities, [Mejare et al., 2003] and thus carry by design the risk of selection bias. The true extent of such biases highlighted above remains unknown, which suggests that all trial results need to be regarded with caution and no conclusions in terms of answering the review question can therefore be drawn.

Concluding remarks. Systematic reviews have been reported to provide the highest form of clinical evidence [Mickenautsch, 2010]. However, the internal validity of such evidence can only be as good as the internal validity of the trials reviewed. Although the trials accepted in this update may be considered to be less affected by attrition bias, their risk of selection- and detection-/performance bias is high. For that reason, further high quality randomised control trials (RCT) are needed, in order to verify (or disprove) the currently available results. Such RCTs should adopt a parallel group design and include randomisation and allocation concealment methods that can effectively prevent direct observation and prediction of the allocation sequence. For this purpose, the maximum randomisation method has been suggested [Berger, 2005]. Covariates of both treatment groups should be tested as to whether they differ at baseline (after randomisation). Recently, use of the Berger-Exner test has been suggested, in order to enable authors of trials to investigate whether selection bias has been introduced into their studies [Berger, 2005; Berger and Alperson, 2009]. Where bias risk has been found, it may be adjusted statistically [Berger, 2005]. Both outcomes should be included in the final trial report. In order to ensure that the lack of blinding may not have led to favouring one treatment over the other, trials should use and report on procedures and tests employed that may limit, or at least monitor, potential bias risk. Moreover, future trials should base their reporting on the CONSORT statement [Moher et al., 2001].

This systematic review identified trials that either (i) showed no difference between the materials or (ii) indicated RMGIC to be more caries-preventive than composite resin with or without fluoride. However, the clinical meaning of these results remains uncertain, as all trials identified during this systematic review are limited by risk of selection- and detection-/performance bias and, for some datasets, attrition bias. In addition, the risk of publication bias was identified. High-quality randomised control trials are needed in order to answer the review question conclusively.

References

Andersson-Wenckert I, Sunnegardh-Gronberg K. Flowable resin composite as a class II restorative in primary molars: A two-year clinical evaluation. Acta Odontol Scand 2006; 64: 334-340.

Bax L, Yu LM, Ikeda N, Tsuruta H, Moons KGM. Development and validation of MIX: comprehensive free software for meta-analysis of causal research data. BMC Med Res Methodol 2006; 6: 50.

Berger VW. Selection bias and covariate imbalances in randomised clinical trials. Chichester: John Wiley & Sons, Ltd., 2005.

Berger VW, Alperson SY. A general framework for the evaluation of clinical trial quality. Rev Recent Clin Trials 2009; 4: 79-88.

Burgess JO, Gallo JR, Ripps AH, Walker RS, Ireland EJ. Clinical evaluation of four Class 5 restorative materials: 3-year recall. Am J Dent 2004; 17: 147-150.

Chalmers TC, Matta RJ, Smith H Jr, Kunzler AM. Evidence favoring the use of anticoagulants in the hospital phase of acute myocardial infarction. N Engl J Med 1977; 297: 1091-1096.

Chung CK, Millett DT, Creanor SL, Gilmour WH, Foye RH. Fluoride release and cariostatic ability of a compomer and a resin-modified glass ionomer cement used for orthodontic bonding. J Dent 1998; 26: 533-538.

Donly KJ, Segura A, Wefel JS, Hogan MM. Evaluating the effects of fluoride-releasing dental materials on adjacent interproximal caries. J Am Dent Assoc 1999; 130: 817-825.

Egger M, Davey Smith G, Schneider M, Minder C. Bias in meta-analysis detected by a simple, graphical test. BMJ 1997; 315: 629-634.

Egger M, Jiini P, Bartlett C, Holenstein F, Sterne J. How important are comprehensive literature searches and the assessment of trial quality in systematic reviews? Empirical study. Health Technol Assess 2003; 7: 1-76.

Ewoldsen N, Herwig L. Decay-inhibiting restorative materials: past and present. Compend Contin Educ Dent 1998; 19: 981-986.

Fuks AB, Araujo FB, Osorio LB, Hadani PE, Pinto AS. Clinical and radiographic assessment of Class II esthetic restorations in primary molars. Pediatr Dent 2000; 22: 479-485.

Gaworski M, Weinstein M, Borislow AJ, Braitman LE. Decalcification and bond failure: A comparison of a glass ionomer and a composite resin bonding system in vivo. Am J Orthod Dentofacial Orthop 1999; 116: 518-521.

Higgins JPT, Green S. Cochrane handbook for systematic reviews of interventions 4.2.6. In: The Cochrane Library, Issue 4. Chichester: John Wiley & Sons, Ltd.; 2006: 82: 113-114.

Jang KT, Garcia-Godoy F, Donly KJ, Segura A. Remineralizing effects of glass ionomer restorations on adjacent interproximal caries. ASDC J Dent Child 2001; 68: 125-128.

Kilpatrick NM, Murray JJ, McCabe JF. A clinical comparison of a light cured glass ionomer sealant restoration with a composite sealant restoration. J Dent 1996; 24: 399-405.

Kjaergard LL, Villumsen J, Gluud C. Reported Methodological quality and discrepancies between large and small randomised trials in meta-Analyses. Ann Intern Med 2001; 135: 982-989.

Kotsanos N, Dionysopoulos P. Lack of effect of fluoride releasing resin modified glass ionomer restorations on the contacting surface of adjacent primary molars. a clinical prospective study. Eur J Paediatr Dent 2004; 5: 136-142.

Lesaffre E, Garcia Zattera MJ, Redmond C, Huber H, Needleman I. Reported methodological quality of split-mouth studies. J Clin Periodontol 2007; 34: 756-61.

McComb D, Erickson RL, Maxymiw WG, Wood RE. A clinical comparison of glass ionomer, resin-modified glass ionomer and resin composite restorations in the treatment of cervical caries in xerostomic head and neck radiation patients. Oper Dent 2002; 27: 430-437.

McDonagh MS, Whiting PF, Wilson PM, et al. Systematic review of water fluoridation. BMJ 2000; 321: 855-859.

Mejare I, Lingstrom P, Petersson LG, et al. Caries-preventive effect of fissure sealants: a systematic review. Acta Odontol Scand 2003; 61: 321-330.

Mickenautsch S. Systematic reviews, systematic error and the acquisition of clinical knowledge. BMC Med Res Methodol 2010; 10: 53.

Mickenautsch S, Yengopal V, Leal SC, Oliveira LB, Bezerra AC, Bonecker M. Absence of carious lesions at margins of glass-ionomer and amalgam restorations: a meta-analysis. Eur Archs Paediatr Dent 2009; 10: 41-46.

Moher D, Schulz KF, Altman DG. The CONSORT statement: revised recommendations for improving the quality of reports of parallel--group randomised trials. Lancet 2001; 357: 1191-1194.

Mjor IA, Toffenetti F. Secondary caries: A literature review with case reports. Quintessence Int 2000; 31: 165-179.

Nagamine M, Itota T, Torii Y, Irie M, Staninec M, Inoue K. Effect of resin-modified glass ionomer cements on secondary caries. Am J Dent 1997; 10: 173-178.

Okida RC, Mandarino F, Sundfeld RH, de Alexandre RS, Sundefeld ML. In vitro-evaluation of secondary caries formation around restoration. Bull Tokyo Dent Coll 2008; 49: 121-128.

Paradella TC, Koga-Ito CY, Jorge AO. Ability of different restorative materials to prevent in situ secondary caries: analysis by polarized light-microscopy and energy-dispersive X-ray. Eur J Oral Sci 2008; 116: 375-380.

Park SH, Kim KY. The anticariogenic effect of fluoride in primer, bonding agent, and composite resin in the cavosurface enamel area. Oper Dent 1997; 22: 115-120.

Rothstein HR, Sutton AJ, Borenstein M. Publication bias in meta-analysis. In: Publication bias in meta-analysis--prevention, assessment and adjustment. Chichester: John Wiley & Sons, Ltd.; 2005a: 1-7.

Rothstein HR, Sutton AJ, Borenstein M. Software for publication bias. In: Publication bias in meta-analysis--prevention, assessment and adjustment. Chichester: John Wiley & Sons, Ltd.; 2005b: 193-220.

Takeuti ML, Marquezan M, Rodrigues CR, Rodrigues Filho LE, Rocha Rde O. Inhibition of demineralisation adjacent to tooth-colored restorations in primary teeth after 2 in vitro challenges. J Dent Child (Chic) 2007; 74: 209-214.

Tantbirojin D, Douglas WH, Verslius A. Inhibitive effect of a resin modified glass ionomer cement on remote artificial caries. Caries Res 1997; 31: 275-280.

Torii Y, Itota T, Okamoto M, Nakabo S, Nagamine M, Inoue K. Inhibition of artificial secondary caries in root by fluoride-releasing restorative materials. Oper Dent 2001; 26: 36-43.

Twetman S, Axelsson S, Dahlgren H, et al. Caries-preventive effect of fluoride toothpaste: a systematic review. Acta Odontol Scand 2003; 61: 347-355.

van Dijken JW. Durability of new restorative materials in Class III cavities. J Adhes Dent 2001; 3: 65-70.

Wiegand A, Buchalla W, Attin T. Review on fluoride-releasing restorative materials-fluoride release and uptake characteristics, antibacterial activity and influence on caries formation. Dent Mater 2007; 23: 343-362.

Wilson RM, Donly KJ. Demineralisation around orthodontic brackets bonded with resin-modified glass ionomer cement and fluoride-releasing resin composite. Pediatr Dent 2001; 23: 255-259.

Yengopal V, Mickenautsch S. Resin-modified glass-ionomer cements versus resin-based materials as fissure sealants: a meta-analysis of clinical trials. Eur Arch Paediatr Dent 2010; 11: 18-25.

V. Yengopal, S. Mickenautsch

Division of Public Oral Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.

Postal address: Dr. S. Mickenautsch, Division of Public Oral Health, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193, South Africa.

Email: neem@global.co.za
Table 1. Criteria for quality assessment of trials: A. Selection bias.

Randomisation and concealment

Score    Criteria                            Impact on bias risk

A        (i)     Randomisation: Details of   Doubts may still exist
                 any adequate type of        whether the trial results
                 allocation method that      are influenced by
                 generates random            selection bias but no
                 sequences with the          indication can be found
                 patient as unit of          from the trial report to
                 randomisation are           support such doubt.
                 reported (1)

         (ii)    Concealment: Trial
                 provides evidence (2)
                 that  concealment was
                 indeed effective and that
                 the random sequence could
                 not have been observed or
                 predicted throughout the
                 duration of the trial.

B        (i)     Randomisation: Details of   Despite the
                 any adequate type of        implementation of method
                 allocation method that      considered to be able to
                 generates random            prevent unmasking of the
                 sequences with the          concealed allocation
                 patient as unit of          sequence through direct
                 randomisation are           observation and
                 reported (1)                prediction, there are
                                             reasons to expect that
         (ii)    Concealment: Trial          the concealed allocation
                 reports on any adequate     sequence may have been
                 method to prevent direct    unmasked during the cause
                 observation (3) and         of the trial.
                 prediction (4) of the
                 allocation sequence and
                 sequence generation rules

C        (i)     Randomisation: Details of   Despite the
                 any adequate type of        implementation of method
                 allocation method that      considered to be able to
                 generates random            prevent unmasking of the
                 sequences with the          concealed allocation
                 patient as unit of          sequence through direct
                 randomisation are           observation, there are
                 reported (1)                reasons to expect that
                                             operators could have
         (ii)    Concealment: Trial          predicted the concealed
                 reports on any adequate     allocation sequence.
                 method to prevent direct
                 operator observation of
                 allocation sequence and
                 sequence generation
                 rules (3). However, the
                 allocation sequence and
                 sequence generation may
                 have been sufficiently
                 predicted.

D        (i)     Randomisation: Details of   Despite the theoretical
                 any adequate type of        chance for each patient
                 allocation method that      to be allocated to either
                 generates random            treatment group, operator
                 sequences with the          knowledge of the
                 patient as unit of          allocation sequence may
                 randomisation are           have lead to patient
                 reported (1)                allocation that favoured
                                             the outcome of one type
         (ii)    Concealment: The trial      of treatment above the
                 report does not include     other
                 information on how the
                 allocation of random
                 sequence was concealed.
                 The allocation could have
                 been directly observed
                 and/or predicted.

0                Trial does not comply       No guaranty of equal
                 with criteria A-D           chance for patients to be
                                             allocated to either
                                             treatment group, thus
                                             allocation may have
                                             favoured the outcome of
                                             one type of treatment
                                             above the other

Baseline data for randomised trials

A                Baseline data collected     Evidence is given that
                 before randomisation and    randomisation has lead to
                 reported for both           equal groups suggesting
                 treatment groups /Data      little risk of selection
                 shows no significant        bias
                 differences between both
                 groups

B                Baseline data collected     Differences have been
                 before randomisation and    adjusted, thus the
                 reported for both           influence of possible
                 treatment groups /Data      selection bias appears to
                 shows significant           be reduced
                 differences between both
                 groups but has been
                 statistically adjusted
                 appropriately

C                Baseline data collected     Reported differences may
                 before randomisation and    be due to ineffective
                 reported for both           randomisation, thus
                 treatment groups /Data      indicate risk of
                 shows significant           selection bias
                 differences between both
                 groups without being
                 statistically adjusted

0                Trial does not comply       No evidence is given
                 with criteria A-C           whether randomisation has
                                             indeed lead to equal
                                             groups with differences
                                             beyond chance, thus
                                             differences may exists
                                             indicating selection bias

(1) Excluded are types of allocation methods that are considered as
inadequate: cluster randomisation, fixed block randomisation with
block size 2, minimization, alternation, randomisation of teeth,
use of date of birth or patient record number, 'quasi'-randomisation,
splitmouth

(2) E.g. by reporting results of the Berger-Exner Test or any other
statistical tests that show that covariates of compared groups were
similar at baseline

(3) E.g. by opening of opaque envelope, obtaining allocation from
tables, computer generated or form other sources

(4) E.g. central randomisation, sequence allocation by other than
operator; excluding varied block randomisation

Table 1. Criteria for quality assessment of trials:
B. Detection/Performance bias.

Blinding / Masking

Score   Criteria                            Impact on bias risk

A       (i)     Trial reports on any type   Evidence is given that
                of method that is known     the trial results may not
                to prevent patient AND      have been influenced by
                operator AND evaluator to   detection/performance
                discern whether patients    bias that may have
                are allocated to the        favoured the outcome of
                test/or the control group   one type of treatment
                (Blinding/Masking)          above the other

        (ii)    Trial reports a process
                with which the effect of
                Blinding/Masking was
                evaluated, as well as the
                results of such
                evaluation

B       (i)     Trial reports on any type   Doubts may still exist
                of method that is known     whether the trial results
                to prevent patient AND      are influenced by
                operator AND evaluator to   detection/performance
                discern whether patients    bias but no indication
                are allocated to the        can be found from the
                test/or the control group   trial report to support
                (Blinding/Masking)          such doubt. However, no
                                            evaluation of the
        (ii)    Trial report does not       Blinding/Masking effect
                give reason for doubt       has been included in the
                that the patient            trial, thus no evidence
                allocation to either the    for lack of bias is given
                test-or the control group
                has been unmasked
                throughout the duration
                of the trial

C       (i)     Trial reports on any type   Despite the
                of method that is known     implementation of method
                to prevent patient AND      considered to be able to
                operator AND evaluator to   prevent unmasking, there
                discern whether patients    are reasons to expect
                are allocated to the        that operators/patients
                test/or the control group   could have discovered the
                (Blinding/Masking)          allocation.

        (ii)    Trial report gives reason
                for doubt that the
                patient allocation to
                either the test-or the
                control group has been
                unmasked throughout the
                duration of the trial

0               No process reported or      Knowledge about the
                implemented able to         patient allocation may
                blind/mask patients AND     have caused patients/
                operators whether           operator to act in a way
                patients where allocated    that may have favoured
                to either the test/or the   the outcome of one type
                control group (It is        of treatment above the
                insufficient to report      other
                that blinding/masking was
                done without reporting
                the details of the
                process)

Table 1. Criteria for quality assessment of trials: C. Attrition bias.

Loss--to follow up

Score   Criteria                    Impact on bias risk

A       Available case analysis,    The trial allows to
        loss/to/follow up           extract evidence that the
        reported per treatment      loss-to-follow up may
        group / Subsequent          have not favoured the
        sensitivity analysis does   outcome of one type of
        not indicate a possible     treatment above the other
        risk of bias effect

B       Available case analysis,    The trial allows to
        loss/to/follow up           assess the risk that the
        reported per treatment      loss-to-follow up may
        group /Subsequent           have favoured the outcome
        sensitivity analysis        of one type of treatment
        indicates a possible risk   above the other
        of bias effect

0       Trial does not report       The trial carries an
        number of included          unknown risk that the
        participants per            loss-to-follow up may
        treatment group at          have favoured the outcome
        baseline or give any        of one type of treatment
        indication that would       above the other
        allow to ascertain the
        loss-to-follow up rate
        per treatment group

Table 1. Criteria for quality assessment of trials: D. Trial endpoints

0    The trial reports on     Even if the surrogate
     secondary of surrogate   results would highly
     outcomes as endpoints    correlate with primary
                              (i.e. clinical outcomes)
                              they cannot serve as
                              valid replacements and
                              need to be regarded for
                              hypothesis development,
                              only

A    The trial reports on     Primary outcomes may
     primary outcomes as      provide evidence for
     endpoints                hypothesis testing

Table 2. Excluded trials with reasons for exclusion in a review of
caries-preventive effect of resin-modified glass-ionomer cement
(RM-GIC) versus composite resin.

Article                             Reason for exclusion

Paradella et al., 2008              No computable data--data presented
                                    in quartiles, median only

Burgess et al., 2004                No computable data--no standard
                                    deviation reported

Takeuti et al., 2007                No computable data--number of
                                    evaluated restorations after 3
                                    years not reported

Kotsanos and Dionysopoulos, 2004    No differentiation of results
                                    between composite versus RM-GIC
                                    reported

Van Dijken, 2001                    No computable data--number of
                                    restorations at baseline not
                                    reported per group

Table 3. Details of accepted trials

                                         RM-GIC treatment group

Article         DS    Patient
                      charac-     Type of     BSL    N     n     LTF
                      teristics   material

Gaworski        01    [1]         Fuji        16     16    6     0
et al., 1999                      Ortho
                                  LC

                02                            16     16    2     0

                03                            16     16    3     0

Chung           04    [2]         Vitremer    25     25    25    0
et al., 1998

Andersson-      05    [3]         Vitremer    66     65    63    1
Wenckert and
Sunnegardh-     06                            66     50    50    16
Gronberg,
2006

McComb          07    [4]         Vitremer    45     44    43    1
et al., 2002    08                            45     34    33    11
                09                            45     19    18    26
                10                            45     9     8     36
                11                            24     24    23    0
                12                            18     18    17    0
                13                            11     11    10    0
                14                            8      8     7     0
                15                            20     20    20    0
                16                            8      8     8     0
                17                            16     16    16    0
                18                            1      1     1     0

Kilpatrick      19    [5]         Vitre-bond  80     66    66    14
et al., 1996

Fuks            20    [6]         Vitremer    40     8     8     32
et al., 2000    21                            40     11    10    29
                22                            40     12    11    28
                23                            40     9     9     31
                24                            40     31    29    9

                           Composite resin treatment        Outcome
                                     group                  measure

Article         DS
                      Type of     BSL    N     n     LTF
                      material

Gaworski        01    Reliance    16     16    5     0      Caries
et al., 1999          Light                                 absence
                      Bond

                02                16     16    1     0

                03                16     16    6     0

Chung           04    Right-On    25     25    21    0      Caries
et al., 1998                                                absence

Andersson-      05    Tetric *    66     62    60    4      Caries
Wenckert and          Flow                                  absence
Sunnegardh-     06                66     50    45    16
Gronberg,
2006

McComb          07    Z100        45     44    39    1      Caries
et al., 2002    08                45     36    29    9      absence
                09                45     24    16    21
                10                45     18    10    27
                11                24     24    19    0
                12                18     18    9     0
                13                13     13    5     0
                14                12     12    4     0
                15                20     20    20    0
                16                9      9     4     0
                17                16     16    16    0
                18                1      1     1     0

Kilpatrick      19    P-50        80     66    66    14     Caries
et al., 1996                                                absence

Fuks            20    Z100        38     9     9     27     Caries
et al., 2000    21                38     8     8     30     absence
                22                38     13    13    25
                23                38     8     6     30
                24                38     32    26    6

                           Evaluation

                                               Dentition/     Study
Article         DS                             Teeth/         period
                      Criteria       Method    Restoration

Gaworski        01    No sign of     Visual    Permanent      14 months
et al., 1999          decalcifica-   exami-    --canines
                      tion around    nation    Orthodontic
                      orthodontic              bracket
                02    bracket                  bonding

                03                             Permanent--
                                               lateral
                                               incisors
                                               Orthodontic
                                               bracket
                                               bonding

Chung           04    No sign of     Visual    Permanent--    4 weeks
et al., 1998          decalcifica-   exami-    central
                      tion around    nation    incisors
                      orthodontic              Orthodontic
                      bracket                  bracket
                                               bonding

Andersson-      05    Modified       Visual    Primary        12 months
Wenckert and          USPHS          exami-    molar
Sunnegardh-     06                   nation    proximal       24 months
Gronberg,
2006

McComb          07    Softness of    Visual    Permanent      6 months
et al., 2002    08    the surface    exami-    Independent    12 months
                09    texture or     nation    of Fluoride    18 months
                10    surface                  use            24 months
                11    defect                                  6 months
                12    adjacent to              Permanent      12 months
                13    the                      Non-Fluoride   18 months
                14    restoration              users          24 months
                15    restoration
                16    is not                   Permanent      6 months
                17    greater                  Fluoride       12 months
                18    diameter                 users          18 months
                                                              24 months

Kilpatrick      19    No visible     Visual    Permanent--    27 months
et al., 1996          caries         exami-    premolar,
                                     nation    molar--Small
                                               occlusal
                                               cavities       12 months
Fuks            20    Modified
et al., 2000    21    USPHS          Visual                   18 months
                22                   exami-                   24 months
                23                   nation    Primary        >25 months
                24                             molars Class   >25 months
                                               II

                                     X-ray

DS = Dataset number; BSL = Number of teeth at baseline; N = Number of
teeth evaluated; n = Number of teeth with caries,
LTF = Loss-to-follow-up; USPHS = United States Public Health Service
criteria; RM-GIC = Resin-modified glass-ionomer cement.

* Composite resin contains fluoride.

Patient characteristics:

[1] 16 patients from a teaching institution participated;
consecutively selected from individuals seeking orthodontic treatment
at Albert Einstein Medical Center in Philadelphia; maxillary and
mandibulary premolar, canine and incisor teeth were bonded allowing
up to 20 teeth per patient to be included.

[2] 26 patients (11 males, 15 females) with mean age of 13.4 years;
all teeth free of decalcification; exposure to fluoride was kept at a
minimum during 4 weeks before treatment and during the treatment;
oral hygiene instructions and non-fluoride tooth-paste given during
this time; fluoride in drinking water 0.03 ppm; no pre-existing
fluoride releasing restorations.

[3] 57 children (30 M and 27 F, with a mean age of 8 years, range
511 years), a total of 66 pairs of restorations were placed; Inclusion
criterion: at least 2 proximal carious lesions in primary molars with
an expected exfoliation time exceeding 2 years; Exclusion criteria:
availability for recall was uncertain, uncooperative, serious health
problems, no parental consent; children were treated at their regular
appointments and no extra time was reserved for participation in the
study; all teeth were vital with no sign of pulpitis.

[4] Inclusion criteria: at least 3 cervical carious lesions in the
same arch; all patients had received prior radiation therapy to head
and neck; age >18 years; patients were capable to give informed
consent; patients xeriostomic.

[5] 67 patients attending the Dept. Child Dental Health at Newcastle
Dental Hospital, UK; some older patients had learning difficulties
or development delay; of the 58 remaining patients (after drop-out) 25
were female 33 were male; mean age 15 years and 1 month (range 8
years/8 months--28 years).

[6] 29 schoolchildren, 15 males, 14 females attending the Dental
School Clinic pf the University of Sta. Maria, Brazil; Inclusion
criteria: age 8-10 years, at least 1 primary molar with interproximal
caries with occlusal and proximal contacting adjacent teeth,
available for recall every 6 months until shedding teeth, parental
consent.

Table 4. Results of individual datasets

Article                    DS     RR        95% CI       p-value

Gaworski et al., 1999      01    1.20     0.46 - 3.15      0.71
                           02    2.00    0.20 - 19.91      0.55
                           03    0.50     0.15 - 1.66      0.26
Chung et al., 1998         04    1.19     0.99 - 1.43      0.07
Andersson-Wenckert         05    1.00     0.94 - 1.07      0.96
and Sunnegardh-            06    1.11     1.01 - 1.23     0.04 *
Gronberg, 2006             07    1.10     0.98 - 1.24      0.10
                           08    1.20     1.02 - 1.43     0.03 *
                           09    1.42     1.05 - 1.92     002 *
                           10    1.60     1.00 - 2.57      0.05
                           11    1.21     0.97 - 1.51      0.09
McComb et al., 2002        12    1.89     1.17 - 3.04    0.009 *
                           13    2.36     1.16 - 4.82     0.02 *
                           14    2.63     1.13 - 6.09     0.02 *
                           15                 n.e.
                           16    2.10     1.04 - 4.24     0.04 *
                           17                 n.e.
                           18                 n.e.
Kilpatrick et al., 1996    19                 n.e.
                           20                 n.e.
                           21    0.93     0.71 - 1.21      0.57
Fuks et al., 2000          22    0.92     0.74 - 1.14      0.44
                           23    1.32     0.86 - 2.02      0.21
                           24    1.15     0.95 - 1.39      0.15

DS = Dataset number; RR = Relative risk; CI = Confidence interval;
n.e. = Not estimable, data from both treatment groups are essentially
the same: p = 1.00. * Statistically significant difference, in favour
of RM-GIC.

Table 5. Results of quality assessment of accepted trials in a
review of caries-preventive effect of resin-modified glass-ionomer
cement (RM-GIC) versus composite resin.

                                        Selection bias

                                                   Baseline
Article                      DS    Randomisation     data

                             01          0            0
Gaworski et al., 1999        02          0            0
                             03          0            0
Chung et al., 1998           04          0            0
Andersson-Wenckert and       05          0            0
Sunnegardh-Gronberg, 2006    06          0            0
                             07          0            0
                             08          0            0
                             09          0            0
                             10          0            0
                             11          0            0
McComb et al., 2002          12          0            0
                             13          0            0
                             14          0            0
                             15          0            0
                             16          0            0
                             17          0            0
                             18          0            0
Kilpatrick et al., 1996      19          0            0
                             20          0            0
                             21          0            0
Fuks et al., 2000            22          0            0
                             23          0            0
                             24          0            0

                                   Detection/
                                   Performance   Attrition
                                      bias         bias

                                   Blinding /    Loss-to-     Trial
Article                      DS      Masking     follow up   outcome

                             01         0            A          A
Gaworski et al., 1999        02         0            A          A
                             03         0            A          A
Chung et al., 1998           04         0            A          A
Andersson-Wenckert and       05         0            A          A
Sunnegardh-Gronberg, 2006    06         0            B          A
                             07         0            A          A
                             08         0            B          A
                             09         0            B          A
                             10         0            B          A
                             11         0            A          A
McComb et al., 2002          12         0            A          A
                             13         0            A          A
                             14         0            A          A
                             15         0            A          A
                             16         0            A          A
                             17         0            A          A
                             18         0            A          A
Kilpatrick et al., 1996      19         0            A          A
                             20         0            A          A
                             21         0            A          A
Fuks et al., 2000            22         0            A          A
                             23         0            A          A
                             24         0            A          A

DS = Dataset number.
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