Sameer Puri D.D.S. Here is some interesting information from Mr. Chet Spivey, who is the director of Clinical Marketing for Ivoclar on their new bulk fill composite. As you know, many companies have technology now that they have developed that allows clinicians to place composites in large increments instead of small layers. Small layers were necessary to control the polymerization shrinkage that occurs with resins. This lead to more tedious placement of the restorations.
Today as technology evolves, the ability to cure up to 4mm in depth is now a reality. No more placing restorations in 2mm increments to control stress and shrinkage. The Tetric EvoCeram material is now available and some pertinent information on how it works is listed below. The information is from Ivoclar and if you wish to find out more, here is a link to their e-newsletter: http://www.ivoclarvivadent.us/update/clinical/Tetric EvoCeram® Bulk Fill
C. Spivey – Ivoclar Vivadent, Inc.
Tetric EvoCeram Bulk Fill represents a significant advancement in the field of resin-based filling materials. What sets this composite material apart from any other is its unique formulation designed to provide faster, more efficient placement of direct composite restorations while sustaining long-term clinical performance.
Unlike traditional composite formulations that may have been simply modified to allow for placement in thicker layers and which may result in compromised esthetics, reduced working time, the need for additional dispensing equipment or placement of a covering layer, Tetric EvoCeram Bulk Fill represents entirely new technology for the faster, more efficient placement of direct composite restorations without compromise to any physical properties.
The Big Secret! (Actually, there are 3…)
Tetric EvoCeram Bulk Fill is defined by its unique formulation. For the first time in dentistry three new patented technologies have been incorporated into a well-proven nano-hybrid composite formulation;
1. Ivocerin® – A new light-initiator which provides deeper and more efficient depth-of-cure and shorter curing time. With Ivocerin, Tetric EvoCeram Bulk Fill can be cured in layers of up to 4 mm in just 10 seconds (using a light with minimum output > 1,000 mW/cm2.)
2. Stress Relievers – New fillers (pre-polymers) reduce shrinkage strain by absorbing the stress generated during the light-curing process. This keeps the material from pulling away from cavity walls avoiding the formation of gaps that could lead to microleakage, black lines at the margin and potential failure of the composite restoration.
3. Light-Sensitivity Filter – A special additive within the initiator system delays the effects of ambient light extending the working time beyond three minutes.
What is Ivocerin®?
Ivocerin is a new germanium-based light-initiator developed by Ivoclar Vivadent and used exclusively in Tetric EvoCeram Bulk Fill. This new initiator allows Tetric EvoCeram Bulk Fill to cure faster and deeper than other composite materials without having to increase translucency or reduce working time. The absorption spectrum of Ivocerin fills the “gap” between traditional light-initiators (e.g. Camphorquinone, Lucerin TPO, PPD) used in today’s most popular composite materials (fig 1.) It not only cures fast, it cures well beyond the 2 mm limit of traditional initiators achieving an efficient depth-of-cure at 4 mm (fig 2.)
(Fig. 1) Ivocerin is more reactive to curing lights and fills the gap between traditional initiators.
How can other manufactures also claim depth-of-cure beyond 2 mm for their “bulk fill” materials?
There are other ways to increase the depth-of-cure of composite materials. However these options can result in compromises to other attributes. Two common options used by other manufacturers to increase depth-of-cure are:
METHOD
COMPROMISE
Increase translucency
Reduced esthetics – When placing highly translucent materials in “bulk” layers, the value will be reduced and the composite will appear gray. This can be accentuated by staining of the underlying tooth structure.
Increase content of traditional light-initiators
Reduced working time – When increasing the amount of light-initiators, the material will become much more reactive to ambient light. This may require the need to turn overhead working lights away to keep the material from polymerizing too fast, and to extend the working time necessary to contour the anatomy of the restoration.
How do the Stress Relievers work?
Undoubtedly the greatest concern of most dentists and their reason for not moving to a “bulk fill” composite is shrinkage. There are two types of shrinkage; Volumetric Shrinkage and Shrinkage Strain (or also commonly referred to as Shrinkage Stress.) Volumetric Shrinkage is not really a concern as long as the Shrinkage Strain can be properly managed. It is the stress, caused by shrinkage strain that causes materials to pull away from cavity walls creating gaps that can lead to marginal leakage, black lines and eventually failure of the composite restoration.
Tetric EvoCeram Bulk Fill includes a new, additional filler technology which actually is flexible and relieves shrinkage strain during polymerization. This keeps the material from pulling away from the walls maintaining marginal integrity on a very high level (Fig.3).
(Fig. 3) Shrinkage Stress Relievers are pre-polymer fillers which absorb stresses generated during light-polymerization. The Stress Relievers have a low modulus (10 GPa) as compared to the glass fillers which have a high modulus (71 GPa), making them much more flexible.
What is a Light-Sensitivity Filter?
Sufficient working time is critical when placing direct composite restorations. No one likes to work under time pressure, or having to turn away the operatory light when attempting to contour the anatomy of a restoration. Tetric EvoCeram Bulk Fill offers the extremely unique combination of a fast curing time with an extended working time. This is due to a special additive within the initiator system patented by Ivoclar Vivadent and referred to as Tempo. This additive acts as a shield surrounding the light-initiators delaying the effects of ambient light. However, dental curing lights are able to penetrate this shield allowing the material to cure in 4mm increments in just 10 seconds!
What about the other properties of Tetric EvoCeram Bulk Fill?
Tetric EvoCeram Bulk Fill is derived from Tetric EvoCeram, a well-proven nano-hybrid composite material and the leading composite material in Europe. As a result of its well-proven nano-hybrid formulation, Tetric EvoCeram Bulk Fill provides;
- high-gloss polish and very low abrasion (wear), extremely important for restorations place in the posterior region. Many dentists have commented on its superior handling properties.
- sculptable, non-sticky handling for easy placement and excellent adaption to cavity walls eliminating the need for flowable liners. (However, using a flowable composite to line the restorations is optional.)
- low volumetric shrinkage in addition to the low shrinkage stress as a result of the shrinkage stress relievers
- high level radiopacity for easy detection on x-rays.
As a result, Tetric EvoCeram Bulk Fill does not require a covering layer (or “top coat), in comparison to the flowable “bulk fill” materials saving valuable time and increasing productivity in the practice. Tetric EvoCeram Bulk Fill is designed to create a monolithic restorations (up to 4mm). If cavities are deeper than 4 mm, the material can be placed in multiple layers up to 4mm each.
What about Shades and Delivery Forms?
Tetric EvoCeram Bulk Fill is available in 3 “Universal” shades which feature translucency on the same level of Enamel, resulting in a natural shade blend with the surrounding tooth structure.
IVA – for restorations in the “A” range (A2 – A3)
IVB – for restorations in the “B” range (B1 – B2)
IVW – for restorations in bleached or deciduous teeth
As a result, these three shades will cover practically the entire spectrum required for restorations in the posterior region.
Tetric EvoCeram Bulk Fill is available in both Syringe and unit-dose Cavifil™ delivery. Due to the pliable viscosity and the material’s ability to adapt easily to cavity walls, additional dispensing equipment is not required for Tetric EvoCeram Bulk Fill.
