Composite warming: why heated composite flows better

Heated composite flows better because its viscosity drops as temperature rises: a thick paste material extrudes from the compule more easily and adapts better to cavity walls and margins. In published studies, heated composite achieved the same or a higher degree of monomer conversion, showed lower polymerization stress and better marginal adaptation. In the clinic, this is done with a composite warmer such as AdDent CALSET or a heated dispenser.

What happens to composite when it is heated

Paste composite is viscous, so it is harder to extrude and adapt to the prepared walls, especially at the gingival margin. When heated several tens of degrees above room temperature, according to the manufacturer AdDent, freshly extruded composite can behave almost like a flowable composite while retaining the filler content of a paste composite. In other words, the clinician gets the adaptation of a flowable without changing the main restorative material.

Important: heating is not curing. Composite is polymerized only by light, while heat increases monomer mobility, so the reaction proceeds more completely. This is why warming is seen not only as a matter of convenience but also of restoration quality.

What the research shows

AdDent provides a list of published studies on heated composite. The main findings:

• Conversion and stress. Calheiros, Daronch, Rueggeberg and Braga: raising the composite temperature allows shorter light exposure and lower polymerization stress while maintaining or increasing the degree of conversion.
• Shrinkage force. Tauböck, Tarle, Marovic, Attin (Journal of Dentistry): preheating significantly reduced the shrinkage force of high-viscosity bulk-fill and conventional composites while maintaining or increasing conversion; the effect depended on the specific composite.
• Adaptation and voids. Bolding, Hill, Tantbirojn, Versluis: restorations made with heated composite were better adapted and had fewer large voids.
• Microleakage. Wagner et al.: heated composite showed significantly less microleakage at the cervical margin than the control group or the group with a flowable liner.
• Class II margins. Elkady, Abdalla, Hasan: preheating composite to 60 °C improved adaptation and reduced the marginal gap.
• Color. Mundim et al.: preheating did not change the optical properties, although the degree of conversion increased.
• Pulp. Daronch: in vitro, heated composite did not significantly increase the temperature in the pulp chamber compared with room-temperature composite.

These studies were conducted with specific materials and under specific conditions, so always follow your composite manufacturer's instructions for use, including the recommended curing time.

Which temperature to choose

AdDent CALSET has three settings: 37 °C, 54 °C and 68 °C. The highest, 68 °C, is most commonly used for composite when maximum flow is needed, for example in the injection technique; the Bioclear Method uses the same temperature of about 68 °C. 37 °C corresponds to body temperature. The device can also warm anesthetic cartridges and ceramic veneers, with dedicated trays for each.

Warmer or heated dispenser?

Composite starts to cool once removed from the warmer, so the workflow must be planned for immediate placement. The advantage of a heated dispenser is that the material is warmed in the instrument itself. For Compex HD users, our online store offers barrier sleeves and silicone sleeves; for the dispenser itself, please contact us.

How to introduce composite warming in your clinic

1. Check your composite. Make sure your composite manufacturer permits warming and note the recommended curing time.
2. Choose a tray by format. Standard tray for compules, dispenser tray for dispensers, 7-slot tray for syringes. They all fit the same CALSET base, so additional trays can be purchased later.
3. Switch the warmer on in advance and wait until the material reaches the set temperature (according to the warmer's instructions for use).
4. Prepare everything before removing the compule: isolation, adhesive, matrix, instruments.
5. Place and adapt immediately, while the composite is warm and flowable.
6. Cure according to the composite manufacturer's instructions. Studies show that heated composite can achieve good conversion even with shorter light exposure, but we do not recommend shortening curing times on your own.
7. Follow infection control: CALSET trays are autoclavable, and so is the CoMax dispenser.

Which composites to warm

Warming offers the greatest benefit for viscous paste composites. Composites supplied in compules include, for example, Vericom DenFil N and DenFil (0.25 g compules). You will find the full range in the Restorative materials section, and warmers and instruments in Clinical equipment and instruments. Prices incl. VAT are shown on each product page.

Not just composite: anesthetic and veneers

The CALSET base with different trays is also used for other procedures. The anesthetic tray warms three cartridges, the ceramic veneer tray warms veneers before cementation, and the universal Multi-Pro tray holds 3 dispensers, 4 compules, syringes and/or polishing instruments at the same time. The manufacturer also states that the warmer can be used to heat finishing instruments for better marginal adaptation. Trays can be changed without tools and are autoclavable, so a single device can serve the entire workstation.

Common mistakes when starting to warm composite

• Removing the compule too early. The composite does not reach the set temperature, so part of the benefit is lost. Switch the warmer on before the patient is seated.
• Leaving the material on the work surface too long. Removed composite cools down, so prepare the cavity, adhesive and matrix first.
• Using the wrong tray. Compules, dispensers and syringes have separate trays; choose based on the format in which you use your composite.
• Shortening curing time by guesswork. Although studies show good conversion, the curing time is set by the composite manufacturer.

Checklist

• The composite manufacturer permits warming, and the curing time is known.
• Temperature selected (usually 68 °C for composite).
• A tray that matches your compules, dispensers or syringes is available.
• The workstation is prepared before the material is removed from the warmer.
• Infection control is in place: autoclavable trays, barrier sleeves.

Want to see CALSET in action or ask which tray suits your materials? Contact IMMT and we will arrange a consultation or demo.