Composite Material: When You Should Go With The Flowable

By praphab144 / stock.adobe.com

Flowable dental composite resins first hit the dental market back in the mid-1990s, providing a distinct difference in handling from their more viscous counterparts. In addition, clinicians saw the need for a material that would adapt to small preps and other specific clinical indications. Often packaged in syringes, flowables could get into small preps that conventional composites could not. 

Since then, dental materials manufacturers continue to improve the performance of dental resin composite materials. Today, there are multiple flowable composite resin options for any given clinical case.

Advances in dental composite materials evened out the performance in esthetics and durability between brands over the years. However, with such an even field, many composites are chosen by what “works best in the clinicians’ hands,” making handling one of the most significant differences between materials. So, are there times that you should pick the one that handles like a flowable? According to our 2 experts, there are. 

Peter Auster, DMD, FACD, private-practice clinician in Pomona, NY, and the founder and past president of the Greater New York Academy of Cosmetic Dentistry, says flowable and injectable composites are improving. He teaches a hands-on course for Catapult Education on the new materials for 2021, “Evolution and Revolution: New World Composite Dentistry,” which addresses choosing the best material choice for each case. It also introduces attendees to understanding how and when to use bulk-fill flowable.

“Their ability to move into ‘nooks and crannies’ is a great benefit,” Dr Auster says.

Per The Journal of Clinical & Diagnostic Research, the properties of flowable composites make them ideal for the following clinical indications:¹

• Minimal occlusal Class I caries
• Preventative resin restorations
• Pit & fissure sealants
• Minimally invasive Class II proximal boxes
• Cavity liner
• Minimally invasive Class III restorations
• Class V abfraction lesions
• Bonding of orthodontic brackets/ lingual orthodontics retainers
• Splinting fractured and mobile teeth
• Emergency reattachment of fractured anterior tooth segment
• Repairing temporary restoration
• Denture repairs
• Repair of ditched amalgam margins
• Repair of crown/composite restoration margins
• To block out small undercuts in indirect cavity preparation
• Repair of small porcelain fractures in non-stress-bearing areas
• Luting porcelain/composite resin veneers
• As a protective based in non-vital dental bleaching
• Bonding of fiber posts in the restoration of endodontically treated teeth

Choosing the proper flowable requires a knowledge of the material composition and the related mechanical and physical properties that result from it. The Journal of Clinical & Diagnostic Research suggests that picking the appropriate flowable material requires this familiarity so the clinician can match the material to the clinical situation.¹ Dr Auster, the American Academy of Cosmetic Dentistry’s 2022 Chairman of the Professional Education Committee, agrees that knowing about the new materials is critical. While most improvements in composite materials are slight, he thinks some exciting things are happening in flowable technology. 

“They are perfect for narrow bondfills, bases under packable restorations, and provisional repairs,” Dr Auster says of the flowable composites available today. “Conventional flowable, however, are not easily carved or condensed. So, except for ‘unconventional’ composites like Viscalor and Sonicfill, I prefer to use compactable composites for large occlusal surface restorations.”

 Visual or Viscalor Bulk by VOCO America uses Thermoviscous Technology, a type of composite that is meant to be warmed so it will be flowable at first and then, after about 20 seconds, will revert to more viscous handling. In a podcast with Viva Learning, Dr Auster explains that the composite has a monomer with a lower melting point than other composites and a silane coating that allows the monomer to change to a lower viscosity when warming. 

Tim Bizga, DDS, FAGD, lectures for the dental industry and is a private practice dentist outside Cleveland, where he does many fillings. He uses flowable every day, often switching between them in restorative procedures. Dr Bizga reaches for a flowable when he thinks a packable composite might create a void in the restoration because it could not get into the tiny crevices of the prep.

“When working with regular composite, if you have a prep that provides space to instrument and manipulate, you can pack it in, and the restoration will take shape. There are, however, situations where this is more difficult. In those situations, I tend to like flowable materials because they can get into difficult preparations that are otherwise too small to fit a composite tip. You see for me, it all boils down to handling,” Dr Bizga says. “That’s why you don’t find any literature suggesting one vs. the other because it comes down to preference.”

Dr Bizga says that there used to be a significant difference in the mechanical properties between the 2 viscosities of materials. Flowables, due to their lower filler volumes, lacked the strength and durability that the conventional composites with higher filler volumes had. Flowables also shrank more during polymerization in the past, which limited their use. However, since the technology continued to improve, Dr Bizga says dental materials manufacturers can get more filler into the materials, making them more universal. 

 “So, I ebb and flow,” Dr Bizga says. “I go-between. I use both in every procedure. There is no reason to be exclusive. You must have both.”

 As a former dental lab technician, Dr Bizga says that his restorative procedures favor the artsy side. He mixes shades and layers to mimic dentition and make the restoration look like more than just a filling. He might use as many as three composites in one filling, especially in the anterior. 

 Dr Bizga reaches for different brands of his favorites depending on what he is doing. For gumline fills, it is Beautiful Flow from Shofu, which has filler technology with a fluoride release. To block out color, Dentsply Sirona’s TPH Spectra ST flow opaque dentin shades. When he needs a base for large fillings, Dr. Bizga likes everX^™ Flow from GC America, which he says is in-between flowable and packable, referred to as an injectable. 

 When he worked in the lab, Dr Bizga liked to work with wax whose handling was more flowable, particularly if he waxed crowns. Now, in the operatory, he finds unique uses for flowable.

 “I like flowable a lot. I use a lot of them in my practice,” Dr Bizga says. “I also like packables because you absolutely have to have them in certain situations, but there are just some occasions that you need an alternative.”

Dr Bizga also likes how the new flowables have adaptable properties. Past flowable were either running like water or a thinned-down version of the packable composites; the latest technology means that the material holds where you place it and spreads around when you need them to, Dr Bizga explains. 

“With materials, the gap is closing,” Dr Bizga says. “It comes down to user handling preference and what you can do with it. I always asked in my lectures, ‘what is the best composite on Earth?’ The answer is the one that works in your hands, and that’s the truth. It’s all about what works for you.”

References

1. Baroudi K, Rodrigues JC. Flowable Resin Composites: A Systematic Review and Clinical Considerations. J Clin Diagn Res. 2015;9(6): ZE18-ZE24. doi:10.7860/JCDR/2015/12294.6129