Fig.1
Nowadays, almost all composite manufacturers are offering so called “universal” composites. Those materials provide clinicians with good aesthetics and a simplified approach. The common feature of these materials is their “chameleon effect” which allows to reduce the need for multi-shade stratification, also thanks to the thickness-based opacity and high polish.

Fig.2
Opacity based on thickness is a key feature when talking about anterior materials. Small class III and IV can be frustrating. Traditional composites are either too opaque (hard to blend them with high thickness enamel in anterior enamel) or too transparent (easy to blend on margins, but tend to turn out grey when used too thick).
Universal composites are a viable solution to such problem. In class III/IV/diastema, when the required material is thick, opacity increases without the grey effect in the end. On the other hand, a thin layer spread on a margin (or incisal edge) can be transparent and blends with natural enamel.

Fig.3
This effect is easily observed clinically. As you can see in this case of diastema closure and incisal lengthening, even inter proximally where the material is thicker, there is no greyish hue. But, at the incisal edge and on the underlying enamel, the material is semi transparent, and blends naturally.

Fig.4
The bad news is those properties are a huge disadvantage when dealing with discolored teeth. As seen in the picture, the same material placed on different bases, behaves differently. Thanks to the chameleon effect, this material turns dark (it blends with discolored enamel) or very opaque when clinicians have to use unnaturally thick layers of material, which leads to a disappointing result. With universal composites, achieving good aesthetic results is simple, yet due to the intrinsic properties of the material, so difficult situations may be even harder to solve.

Fig.5
But not all universal composites behave the same way. For example, the XW shade from the 3M Filtek Universal Restorative set has same chemical and structural properties as the other universal shades, but with different optical properties. It’s engineered to generate a higher value restoration, while providing extra opacity even at lower thicknesses.

Fig.6
On the other hand, it doesn’t have the chameleonic effect of other universal shades, meaning it stays white no matter the substrate. This clinical picture shows this effect clearly. The light source is positioned similarly in both cases. Natural color – transmits light, giving a very natural effect, while the XW shade blocks the light, even though thickness is limited. Contrary to the opaquer material (A1) it’s still warm and natural.

Fig.7
Clinically, we can use this material in several ways. We can generate extra white smiles for patients desiring one, without creating thick teeth, and without worrying about bleaching prior to the restorative procedure. Also, we can use it when a patient wants a natural effect. The picture shows the case of a young patient with history of trauma and unsatisfactory internal bleaching. Her desire was to get rid of the dark central, but without too much damage at the same time. In such cases, we can try to achieve an aesthetic result with direct composite on both centrals to achieve the same color and opalescence. If we were to use a universal composite only, we wouldn’t have been able to cover the discoloration without generating unnatural thickness. On the contrary, by placing a thin layer of Filtek Universal Restorative XW as a base layer on both centrals, we were able to visually block the discoloration and achieve matching color on both centrals.

Fig.8
Because Universal composites blend with the substrate color we used an A2 shade on top of the XW base, to achieve an A1 final shade. After shaping using the Essential Shape concept by StyleItaliano, we could achieve matching shade and hue on both centrals. Thickness is low and natural, as well as opacity.

Fig.9
Utilizing the XW shade as a base can be helpful in numerous clinical situations. Direct composite bonding can generate satisfactory and life-changing results for our patients.

Fig.10
Before and after.

Fig.11
Even when each tooth in a smile is different, using XW as a blocker and brightener for natural results can lead to very satisfactory outcomes.

Conclusions

I believe that such solution can lead to simple, predictable and satisfactory results in smile changing procedures for our patients. Thanks to updated composite materials, direct composite bonding can be a procedure performed even in difficult clinical situations.

Bibliography

1. de Abreu JLB, Sampaio CS, Benalcázar Jalkh EB, Hirata R. Analysis of the color matching of universal resin composites in anterior restorations. J Esthet Restor Dent. 2021 Mar;33(2):269-276. doi: 10.1111/jerd.12659. Epub 2020 Sep 29. PMID: 32989879.
2. Baldissera RA, Corrêa MB, Schuch HS, Collares K, Nascimento GG, Jardim PS, Moraes RR, Opdam NJ, Demarco FF. Are there universal restorative composites for anterior and posterior teeth? J Dent. 2013 Nov;41(11):1027-35. doi: 10.1016/j.jdent.2013.08.016. Epub 2013 Aug 31. PMID: 24001506.
3. Okeson JP. Tooth Wear Management of Temporomandibular Disorders and Occlusion. 2008, 6th edition Mosby, St Louis 245-247.
4. Goldstein MB. Universal composite resins: the “do-all” workhorses of dentistry…a system survey. Dent Today. 2005 Feb;24(2):160, 162, 164 passim. PMID: 15768951.
5. Ghazal M, Albashaireh ZS, Kern M. Wear resistance of nanofilled composite resin and feldspathic ceramic artificial teeth. J Prosthet Dent. 2008 Dec;100(6):441-8. doi: 10.1016/ S0022-3913(08)60262-0. PMID: 19033028.
6. Monteiro P. Essential Shape. The key to a tooth-like restoration. Styleitaliano.org, June 2020.
7. Vanini L, D’Arcangelo C, Indelli P, Bellizzomi P. Estetica, funzione, postura. 2018 Edizioni Acme.