Generally YES however Coltene is working on a new composite called Fill Up! which is bulk filled. Im participating in the clinical study of that material, just started using it on my patients. Karolina
Absolutely NO. You can be able to polymerize 4-5 mm of composite according with lab data, but you cannot handling this thickness. The first layer must be not more than 1 mm. For the second and third layer you have a choice, but in my opinion it is better a layering technique, in order to have the better control of composite.
All composite resins should be polymerized in thin layers particularly in horizontal manner. There were no sufficient data available for curing in oblique direction. My opinion it is not suitable because oblique curing will increase the chance for inter-facial shrinkage and gap formation.
First off for those who don't look back but for 5-10 years in the dental literature you are doomed to repeat the newest philosophies without considering the history and outcomes. Back in the early 1980's we researched the curing abilities of composite resins penetrating the light from the facial and lingual aspects and measuring cure by hardness and bonding to enamel. Then by bonding to dentin. The long and short was that we could cure through 7+ mm of tooth from the facial, say through a maxillary cuspid to use a light cured composite resin, Silux, to bond metal phalanges of acid-etched resin bonded fixed partial dentures. The bond were the same as composite resin to enamel and the the hardness below the brackets when debonded was the same as buttons of the composite resin discs 1X20 mm used to test water sorption. We then took it to a Pedo grad thesis and to orthodontic brackets for 6X6 and now today this is the way Fast Braces bonds their brackets. Dentin microleakage of bulk placed restorations cured through the facial and lingual interproximal areas were measured and were actually slightly better than horizontal placement techniques. I have just retired from 40 years of private practice, military practice, teaching and Biomaterial and Clinical research (having received a MS in Biomaterials and Clinical Research in 1988). I used this technique in my private practice for over the last 20 years and my composite resin placed from my records have lasted an average of 14.5 yrs for all composite resins, Classes 1, 2, 3, 4, 5, all bulk filled and cured through the enamel facial and then lingual surfaces of the tooth and interproximal spaces. None of the classes stick out in statistical significance, that is to say just as many Class 2 failed as did the other classes. So I have seen that incremental, horizontal and vertical, and by the way several papers find no real significance to leakage placing either horizontal or obliquely, is no better and much slower than bulk placement and additionally curing for 20 sec through the facial and lingual surfaces. And for the skeptics, I did not have patients reporting sensitivity after placement of composite resins.
Bulk filling is possible with specially designed materials like SDR (a transparent flowable composite with big fillers and a stress-relieving component within the matrix) that does not develop too great shrinkage stress and allows a deep-enough curing of the material. However, in bigger cavities, I prefer the oblique layering technique, also due to the not so favourable C-factor of cavities.
The question is addressing two topics:
1) layering technique of light curing composites
2) bulk-filling
Ad 1): It does not matter whether oblique or horizontal increments are used. On the one hand, it is important that the material is well adapted to the tooth structure during the application process. On the other hand, it is important that the largest possible free surface area makes it possible to compensate for stresses by flow. This means it is more important to understand the concept of stress reduction (flow due to free surfaces) than to follow a cookbook (horizontal vs. oblique).
2) Bulk-filling is only possible with specialized materials as Johannes already pointed out!
If you are interested in bulk-filling:; there are two different concepts to follow: one-for-all (like Tetric evo ceram bulk fill/Vivadent) or the low-flow-plus-cover-composite approach (as was introduced by Dentsply with SDR).
The first has the advantage of one material only, but you have to take care to adequately adapt the material to the tooth tissues.
The second has the advantage of perfect adaptation to the tooth due to the low viscosity, but makes the manufacturer rich as you have to apply a second material on top. The marketing claims of time benefits are gone if you apply the material this way!
Oblique Incremental filling techniques reduce polymerized material volume and decrease shrinkage stress . Each increment is compensated by the next,. This results in less damaging polymerization shrinkage .
Furthermore, I think we need more research and a greater clinical decline with bulkfill composit.@ alok Dubey
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