02 December 2022

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Can lubricant materials be used to model resin-based composites?

Lorenzo Breschi

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Introduction

Modeling of composite resins is currently one of the bases of modern restorative dentistry. Several lubricant materials can be used to model resin-based composites (RBCs). Clinically, instruments or brushes are wet with bonding agents (BAs) or modeling liquids (MLs) for sculpturing purposes. Paolone et al. recently aimed to analyze existing scientific literature to explore advantages and limits of lubricant materials used during restorative procedures.  

Materials and methods

Five databases were searched, including a review of 295 in vitro studies on the use of lubricant materials for modeling RBCs during restorative procedures. Only English language articles were included, with no limits on the publication date. The most recent research was published in March 2022.  

The present study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews in terms of: (1) identification of the research question, (2) identification of relevant studies (keywords and databases), (3) determination of inclusion and exclusion criteria, (4) data extraction, and (5) summary of the results.  

Results

In the 17 studies included in the review process, a total of 17 BAs and 7 MLs were investigated. Tensile (n = 5), flexural strength (n = 2), water sorption (n = 2), color stability (n = 8) and translucency (n = 3), micro-hardness (n = 4), roughness (n = 3), degree of conversion (n = 3), and monomer elution (n = 2) tests were carried out.   In general, a maximum of 24 hours of artificial storage was performed (n = 13), while four papers tested the specimens immediately.  

Conclusion

Clinicians should be aware that sculpturing RBCs with modeling resins might influence the composite surface properties in a way that is material dependent. The use of non-solvated adhesives (3-step etch-and-rinse, ER) or modeling resins enhances the cohesive bond strength between RBC layers.  

Higher color stability was reported with non-solvated adhesives or modeling resins between RBC layers. Increased translucency values were observed when lubricants were used. However, after lubricant application, finishing and polishing procedures were not always able to provide similar surface properties to specimens treated with no lubricants.  

The effect on the degree of conversion depended on the type of lubricant and RBC. MLs and self-etched adhesives presented higher monomer elution with respect to ER adhesives.

Paolone G, Mazzitelli C, Josic U, Scotti N, Gherlone E, Cantatore G, Breschi L. "Modeling Liquids and Resin-Based Dental Composite Materials-A Scoping Review." Materials (Basel) May 2022; 15; 3759. doi: 10.3390/ma15113759