More Time For Beautiful Restorations

  • Date: November 19, 2018
Estelite composite RAP technology article

More sculpting time and just a 10 second cure!

Radical Amplified Photopolymerisation (RAP) is just one of the technological breakthroughs that have led to Estelite winning ‘Best Universal Composite’ for the last nine years in a row.

The essential feature of patented RAP technology is its ability to polymerise photo activated composites in just one third of the time of that required by other composites. In conventional composite technology, it is accepted that reduced polymerisation time is at the expense of working time: the faster the curing time, the shorter the working time. However, due to RAP technology, Estelite composite has both the benefit of a 10 second curing time and long working time of at least 90 seconds.

Traditional Composite Polymerisation

  • Figure 1: Traditional composites energise one molecule per cycle
  • Figure 2: Using RAP technology, Estelite energises multiple molecules per cycle

In conventional composites, photo-polymerisation involves camphorquinone (CQ initiator) and amine (co-initiator). The camphorquinone is activated by light energy which deprives the amine of hydrogen, resulting in a free radical. This free radical interacts with a monomer molecule leading to polymerization. As a result of polymerisation, the CQ reverts to being inactive. Once more the light reactivates the CQ, an amine molecule is deprived of hydrogen and another cycle begins and so on until polymerisation is complete.

RAP Technology

In Tokuyama’s patented process, amine is replaced by the RAP initiator. The energy transfer takes place between the activated camphorquinone (CQ) and the Radical Amplifier (RA) which, unlike the conventional process, energises RA several monomer molecules at once, dramatically speeding up polymerisation. Having transferred its energy to the RA, the CQ returns to its initial state, is reenergised and the process starts again.

Because the CQ is recycled and energises multiple monomer molecules with each cycle, the amount of CQ needed in the material is reduced by two thirds. This is why the material is less susceptible to premature polymerisation by ambient light, the benefit of which is increased working time.

Another benefit and key feature of reduced CQ is that it contributes to reducing shade change before and after cure.

Estelite advantages:

  • Extended working time – at least 90 seconds
  • Quick curing time – 10 seconds
  • Exceptional handling
  • Superb fast, long-lasting polish
  • Superior shade matching
  • High wear resistance and little abrasion to opposing teeth
  • Minimal shrinkage after light curing (1.3% linear).

In summary, RAP technology enables a dentist to be relaxed whilst sculpting and designing the restoration. When completely satisfied with the design, only 10 seconds are needed for a complete cure!

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