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Title Flowable Resin Composites Reduce Microleakage When Applied As a Liner
Clinical Question When used as a lining material, do flowable resin composites reduce the amount of microleakage compared to restorations without a lining material?
Clinical Bottom Line The use of a flowable resin liner (whether a flowable composite liner, a flowable compomer, or a flowable resin-modified glass ionomer liner) in the sandwich technique to restore teeth can result in less microleakage around the restoration interface. When using a nanofilled composite restorative, all three types of flowable resins significantly reduce microleakage. However, when using a packable composite, resin-modified glass ionomer liners are most effective. This may be due to the fact that packable composites shrink less than nanofilled composites and hence the effect of the liner is not as pronounced. In addition, the fact that flowable composites create a micromechanical interlocking with the hybrid layer while resin-modified glass ionomer liners utilize a chemical bond may also contribute to the increased efficacy of the glass ionomer liners.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 19544820Sadeghi/200972 unrestored, noncarious maxillary first premolars recently extracted for orthodontic reasons.In Vitro Study
Key resultsAccording to Sadeghi et.al., no groups completely prevented the dye from penetrating the teeth, but the use of a flowable resin liner under the composite (whether a flowable composite or a flowable compomer) resulted in less microleakage (p<0.05). It was also found that packable composite groups had significantly lower microleakage than nanofilled composite groups. This is expected since packable composites have much higher filler loading and hence lower polymerization shrinkage thank nanofilled composites, which should reduce microleakage.
#2) 21814362Simi/201136 intact extracted molars free of caries, restorations and cracks. In Vitro Study
Key resultsSimi et. al., found that groups restored with nanocomposites without liners exhibited significantly higher microleakage than those with liners, whether a flowable resin composite liner or a resin-modified glass ionomer liner. Additionally, they found that the use of a flowable resin liner that is 0.5-1.0mm thick greatly reduce the amount of leakage.
#3) 21702678Kasraei/201148 noncarious & nonrestored maxillary molars recently extracted for orthodontic reasons.In Vitro Study
Key resultsKasraei et. al.,found that groups that used resin-modified glass ionomer (RMGI) liners had significantly reduced leakage as compared to those without liners (p<0.01). The use of flowable composite resin liners failed to reduce leakage as compared to those without liners. This study also indicated that the type of adhesive system did not have an impact (p=0.527).
Evidence Search microleakage and flowable composite as a liner
Comments on
The Evidence
Validity: Each of the authors, Kasraei, Simi and Sadeghi employed the gold standard in that a stereo-microscope was utilized to observe the amount of dye penetration. Each tooth was then graded on a scale 1-4 by an observer who was blind to which teeth received a liner. Perspective: Flowable composites do seem to work as a liner that reduces microleakage although some of the tests did not have a statistically significant reduction. This lack of significance in some of the results may be due to the small sample sizes and the graded scale used to rate the amount of microleakage. A better technique that measures the surface area of dye penetration may give more accurate results. In addition, clinical trials are needed to observe the added effects of mastication, normal physiologic movements or extremes in temperature. The effect of using a liner may not be as significant when those factors are included. Based on the current results, if a liner is chosen, flowable resin modified glass ionomers should be the first choice. A flowable composite liner can also be used especially with nanofilled composites. However, since flowable composite liners were not as effective when lower-shrinking composites, such as packable composites, were used, the additional cost of applying a liner should be discussed with the patient and the benefits weighed.
Applicability Flowable resin-modified glass ionomers may be beneficial for reducing marginal leakage in patients receiving treatment for carious lesions. Flowable composite liners and flowable compomer liners may also be beneficial, especially when the tooth is restored with a nanofilled composite, but because the effect is not as strong, its use should be decided on a case-by-case basis weighing the added cost of the use of the liner.
Specialty/Discipline (General Dentistry) (Restorative Dentistry)
Keywords Flowable resin composite liner, Microleakage and liner
ID# 2634
Date of submission: 02/26/2014spacer
E-mail schwind@livemail.uthscsa.edu
Author Courtney Schwind
Co-author(s) e-mail
Faculty mentor/Co-author Kyumin Whang, PhD
Faculty mentor/Co-author e-mail whang@uthscsa.edu
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