Susan McKernan DMD, MS, PhD
The results of this meta-analysis suggest that resin-based sealants can be recommended for clinical use.
A meta-analysis, limited by a lack of assessment of methodological quality, found that light-polymerizing resin-based dental sealants had a five-year retention rate of 83.8%.
Which dental sealant materials are the most effective in terms of retention rates of intact pit-and-fissure sealants?
The authors searched three databases (MEDLINE, EMBASE, and CENTRAL) through Sept. 30, 2011 for articles published on clinical and field trials of at least two years duration. They excluded case reports and in vitro studies. The outcome of interest was retention rate of intact sealants at the tooth level. The authors reviewed the full texts of 485 articles of potential interest and reduced this number to 110 for the meta-analysis. Detailed data for the included studies are presented in the additional online content for this article, including information regarding study design, sealant material, sample size, number of teeth sealed, and number of teeth with intact sealants at various observation times. The authors used random effects models for longitudinal logistic regression and Bayesian statistics to model time courses for the retention rates of pit and fissure sealants for each group of materials.
The authors included 110 clinical and field trials in their meta-analysis. They summarized trials for seven categories of sealant materials: UV-light-polymerizing resin-based sealants (first generation sealants), auto-polymerizing resin-based sealants (second generation), light-polymerizing resin-based sealants (third generation), fluoride-releasing resin-based sealants, flowable composites, compomers, and glass-ionomer cement-based sealants. Two-, three-, and five-year retention rates with 95% credibility intervals (CIs) (used in Bayesian statistics and interpreted similarly to confidence intervals) are reported for six of these categories. The authors did not calculate rates for flowable composites since the maximum follow-up time for the three relevant studies was only two years. Overall, the three resin-based sealant material categories had the highest five-year retention rates: 83.8% (95% CI: 54.9-94.7%) for light-polymerizing, 69.9% (95% CI: 51.5-86.5%) for fluoride-releasing, and 64.7% (57.1-73.1%) for auto-polymerizing resin-based sealant materials. Glass-ionomers and compomers had five-year retention rates of 5.2% (95% CI: 1.3-15.5%) and 3.8% (0.2-31.8%), respectively.
Five-year retention rates of dental sealants were highest for resin-based sealant materials, followed by glass-ionomers and compomers. Among resin-based sealant materials, light-polymerizing materials had the highest five-year retention rates. Two- and three-year retention rates were comparable for the three types of resin-based sealants reviewed.
Source of Funding:
The authors report no financial support from commercial sources for this review.
Importance and Context:
Dental sealants offer an effective way to prevent pit-and-fissure caries. Their effectiveness is generally considered to be dependent on long-term retention. (1) The clinical decision of what sealant material to use depends on multiple factors, including handling properties, ability to obtain moisture control, and tooth eruption status. Findings from this meta-analysis may help clinicians choose materials.
Strengths and Weaknesses of the Systematic Review:
Strengths of this meta-analysis include the large number of studies and population size included in the meta-analysis. Additional online content provides detailed information about the included studies; however, the authors fail to describe their inclusion and exclusion criteria. They did not provide a flow diagram for the process of identifying relevant studies, nor did they state who reviewed the studies considered for inclusion, how disagreements between reviewers were resolved, nor assess the level of agreement between reviewers. Other limitations include no stated language restrictions and lack of searching grey literature, unpublished literature, or hand-searching relevant journals for additional related studies. The authors calculated pooled estimates of retention rates with a random effects model. They did not consider potential sources of bias, including threats to internal validity, external validity, or publication bias.
Strengths and Weaknesses of the Evidence:
This meta-analysis examined two- to five-year retention rates of intact sealants as the relevant endpoints for comparing performance of materials used as sealants by evaluating clinical and field trials. Although this meta-analysis examined a large number of clinical and field trials, major sources of potential bias were not discussed. For example, the authors did not include or account for drop-out rates from each study in the meta-analysis. Likewise, they did not report or address other sources of study heterogeneity, including the use of a rubber dam, presence of a dental assistant during placement, and whether sealants were placed in a practice or field setting. The authors did not include a sensitivity analysis to compare retention rates between clinical and field trials of various materials. While the authors do differentiate among several types of resin-based sealants, they fail to differentiate among major types of glass-ionomer sealant materials (e.g., resin modified and conventional). The reported summary retention rates are associated with relatively wide credibility intervals. The authors translate five-year retention rates into clinical recommendations based on the assumption that longer retention will translate into greater caries protection for pit-and-fissure surfaces. However, they did not consider cariostatic effects in this meta-analysis. Fluoride release from glass-ionomers and fluoride-releasing resin-based sealants may offer additional protective benefits independent of sealant retention.
Implications for Dental Practice:
Light-polymerizing resin-based dental sealants offer the highest five-year retention rates. However, clinicians should also take into account additional factors such as the ability to obtain moisture control and tooth eruption status when selecting a sealant material (1).
1) Beauchamp J, Caufield PW, Crall JJ, et al. Evidence-based clinical recommendations for the use of pit-and-fissure sealants. A report of the American Dental Association Council on Scientific Affairs. J Am Dent Assoc 2008;139(3):257-67.