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The science behind bulk-fill

22 June 2016

The science behind bulk-fill

In an age when evidence-based dentistry is widely accepted as the ‘gold standard’ in dental care,1 we present insight into some of the credible data that supports the use of bulk-filling  in practice.*

Placing posterior composite restorations has always been a tedious procedure, cutting into your time and draining your bottom line. However, today’s technology offers a momentous alternative – easy and dependable bulk-filling.

Just imagine the benefits for your team and your patients resulting from equipment that facilitates:

• Excellent adaptation and handling

• High depth of cure

• Lasting marginal integrity

• Improved aesthetics, durability and more working time.

The good news is that 21st century technology allows clinicians to transform wearisome, repetitive posterior restorations into simple and reliable single-fill placement; in some cases filling cavities up to 5mm in depth in a single increment, with a single material – and with no need for a liner or capping layer.

Evidence supporting clinical excellence

Of course, every dentist needs to know that any new piece of equipment has a qualitative evidence base before they can even consider bringing it into the practice. With this in mind, what is available?

The evolution of technology has spawned the introduction of a sonically activated composite resin that can achieve single-step restorations up to 5mm in depth. This technology has been tested and validated in independent studies in Europe and the USA. The most important results investigated marginal integrity on dentine and enamel, and marginal integrity on enamel with different bonding agents.2

For example, after evaluating the marginal integrity of four bulk fill dental composite materials, Orlowski  and colleagues were able to conclude: ‘The study showed that bulk fill flowables or sonic activated flowable composite restorations have better marginal sealing (lack of discolouration) compared to bulk fill paste like composite’.2

In addition, having considered the combination of sonic energy and its dedicated bulk-fill composite material, Drechsler and colleagues stated: ‘The particle mobility initiated with dispensation that permits the viscosity reduction during placement still exists as the material is being cured. The result is that as the polymer network forms, it has more mobility; it is less confined because of the lack of structure around it. This delays the gel point of the material so that more shrinkage occurs before the material reaches this gel point – or the point at which shrinkage stress starts to accumulate. Thus it can be seen that sonicated material has a slower rate and lower absolute value for shrinkage stress, compared to material that has been at rest. Along with the use of a low-shrinking resin, this effect on the curing kinetics of the material further contributes to higher levels of marginal integrity and lower levels of tooth flexure, even though a larger composite mass is being cured.’ 2

Looking to the future

Technology is ever-evolving, so what the future holds is in terms of composite is on the able hands of dental scientists, which, no doubt, will be rolled out as soon as the evidence base is there, so watch this space.

In the meantime, if you would like more information on what Kerr has to offer you today, please visit, call 01733 892 292 or email


1. Kishore M et al. Evidence based dental care: integrating clinical expertise with systematic research. Journal of Clinical and Diagnostic Research 2014; 8(2): 259-262

2. Accessed 21 June 2016

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