The Benefits of Heating Composite
Posted by Dr. John Kanca III, DMD on July 22, 2019
By Dr. John Kanca III, DMD
For years, dentists have been heating composite to improve the flowability and adaptability of the material. The concept of heating composite is quickly gaining popularity. Large manufacturers such as 3M and VOCO ® are now selling composites that are intended to be heated. The methods of heating composite range from techniques as mundane as hand friction and coffee mug warmers, to more advanced technology such as the CALSET ® Composite Warmer from AdDent Inc. or the Phasor™ photon induced heating gun from Vista Dental.
The following explores the benefits of heated composite, along with existing and emerging heating technologies that are available to dental professionals.
THE ADVANTAGES OF HEATED COMPOSITE
There are three distinct advantages of heating composite prior to light polymerization:
- Better marginal adaptation. In studies that compared room-temperature composite to heated composite, the heated composite provided enhanced adaptation to cavity walls, resulting in significantly less microleakage.1,2 These results are directly correlated to the lower viscosity of the heated material. When heated, highly filled composites flow up to 10 times better7. This enhanced flowability allows composite to thoroughly fill fissures throughout the cavity prep, leaving fewer gaps and voids.
- Increased polymerization. Scientific evidence shows that light curing a heated composite results in a greater mobility of monomer molecules within the resin, along with more free radical formation, resulting in a higher degree of conversion.3,4 Further test data demonstrates that when heated composite is cured immediately after placement, a greater depth of cure is achieved in the same amount of curing time, resulting in a much stronger restoration.5,6
- Improved handling/sculptability. A benefit the clinician will realize immediately is that composite is easier to shape and sculpt once heat has been applied. The analogy often used by clinicians who regularly heat their composite is that trying to fashion and form non-heated composite is like trying to spread cold butter on soft bread, while handling heated composite is like spreading warm butter. Sculpting composite with reduced viscosity is a much more predictable task that requires less effort and leads to enhanced ergonomics when extruding the composite. Hand instruments also tend to stick less to heated composite, adding even greater efficiency and time savings to the procedure.
IS THERE A CONCERN THAT HEATING COMPOSITE WILL COMPROMISE ITS EFFICACY?
So, how hot is too hot? There are two main factors to consider when determining the optimal temperature to heat composite. First, the material must not be so hot as to harm the patient or clinician should the material come into contact with skin, pulp, or other tissue. Second, the temperature should not adversely impact the efficacy of the resin itself.
The general consensus is that the ideal temperature to heat dental composite is between 145°F and 155°F (~63°C – 68°C). This temperature range has been proven not to damage pulp tissue8, and research has shown that it delivers the preferred viscosity while not impacting the color stability or opacity of the resin.5
WHAT IS THE BEST METHOD FOR HEATING COMPOSITE?
The best heating solution is one that can consistently heat composite to approximately 150°F and sustain that temperature throughout the duration of the procedure. From a productivity and convenience perspective, a secondary consideration would be the speed at which the composite can be heated to the desired temperature.
The “homemade” coffee mug solution is not recommended, as there is no reasonable way to ensure a desired temperature is achieved every time. An excessively high temperature, such as 180°F or more, may harm tissue or adversely affect the resin performance. Furthermore, once the composite is removed from the mug, the resin will start to cool. If it is not used right away, or if a layering technique takes several minutes to complete, the viscosity of the material will change throughout the procedure.
Using standard electrical heating methods, CALSET®, was the first mainstream device specifically designed to heat dental composite. Introduced decades ago by AdDent Inc., it remains as one of the more popular heating products on the market today. The CALSET® warmer is versatile, as it can accommodate a variety of composite dispensing gun models, and has the ability to heat multiple compules and/or syringes at the same time.
When powered on, the CALSET ® takes 14 minutes to warm up, and then it takes 3 minutes to heat composite to the specified temperature of 155°F. Just like the coffee mug, the composite will begin to cool down and rise in viscosity immediately upon being removed from the device.
Launched in 2018 by Vista Dental, the Phasor™ leverages near-infrared technology to rapidly warm composite compules. The Phasor™ is a point of delivery system, meaning it heats and dispenses composite in the same device (a separate dispensing gun is not needed).
The most prevalent benefits of the Phasor™ are that it heats composite to 150°F in just 45 seconds, and, unlike other heating devices on the market, it will sustain that temperature throughout the entire duration of the dental procedure. An additional benefit offered by Phasor™ is the fact that it is cordless, and therefore readily available for chairside use. Traditional benchtop warmers that are distantly located, tethered to a countertop or wall, can prevent a seamless integration of heating composites into the restorative procedure. Note that the Phasor™ is only compatible with composite compules (not syringes).
CONCLUSIONS AND RECOMMENDATIONS
The benefits of heating composite are very clear. Better adaptation, polymerization, and handling will lead to superior clinical outcomes. To ensure the efficacy of the composite resin, and the safety of the patient, heating methods should rely on regulated medical devices.
Some device manufacturers, including Vista Dental, offer free trials on heating devices. If you have never tried heating composite, taking advantage of a free trial is a good way to remove risk from your purchase. If you prefer using composite from a syringe, a device such as the CALSET ® from AdDent Inc. is a good choice. If you prefer using compules, the Phasor™ from Vista Dental is an emerging technology that is worth exploring.
1. Composite pre-heating: Effects on marginal adaptation, degree of conversion and mechanical properties; Nivea Regina Froes-Salgado, et al; Dental Materials September 2010.
2. Improving Composite Resin Performance Through Decreasing its Viscosity by Different Methods; Kusai Baroudi and Said Mahmoud; The Open Dentistry Journal 2015.
3. Factors affecting polymerization of resin-based composites; Maan M Alshaafi; Saudi Dental Journal April 2017.
4. Color Stability, opacity, and degree of conversion of pre-heated composites; Fabricio Mariano Mundim, et al; Journal of Dentistry July 2011.
5. Why CALSET®; Dr. Frederick Rueggeberg; Addent.com.
6. Effect of pre-heating on depth of cure and surface hardness of light-polymerized resin composites; Munoz CA; American Journal of Dentistry, 2008.
7. Effect of pre-heating on the viscosity and microhardness of a resin composite; Lucey S; Journal of Oral Rehabilitation 2010.
8. Effect of composite temperature on in vitro intrapulpal temperature rise; Darouch M, et al; Dental Materials October 2007.
CALSET® is a registered trademark of AdDent Inc.