Tooth VS Restorative Material

The Shade That Is Part II: Knowing Your Tooth VS Restorative Material

In order that we achieve better restoration and can be aesthetically sound, we need not only have to define the tooth’s anatomy by carving it properly but we need to choose the proper shade of our restorative material, so, we can have a successful result. We tend to forget that our teeth is NOT a unified color but a varied one. Using a single shade of your composite resins are commonly done nowadays. It is probably either due to time constraint or we just simply don’t want to make an effort anymore. This is not really a problem if we are treating multiple restorations. In fact, since, our patients don’t know any better they are quite happy with our work even if we really didn’t do much effort. Like every one else the price of their treatment trumps any complaints they may have in our work. Well, that is, I guess, all is well and good but there are still some dentists, I hope, who prefer to be better than themselves. And, these are the dentists who I am painstakingly doing this blog for. I think it comes with age that appreciation to one’s craft take over and the ability to do your work according to the level of your own judgement becomes more important. Personally, if I am not happy with what I did even if the patient is ecstatic is something that doesn't satisfy me anymore. Priorities of my goals in my career as a dentist became different as I were able to already fulfilled my mundane and selfish goals in life, and, now, I found myself to be looking more on what can make me better not only as a professional dentist but as a person. I am more critical in my own work than not. Providing an excellent work to my patients according to my judgement becomes more important than what I earn and time I need to get it done. Therefore, in order to truly achieve better restorations according to the level of a professional that we are, I finally realized that in order to achieve that, I need to understand the materials I used versus the tooth structure where I am placing it. So, let’s tackle the issues one by one.

I. Restorative Materials

For this blog, I will discuss composite resins but only within the limits first of shading because it will take a book to tackle everything else. And, I doubt if you can retain let alone be studious enough to read it all. So, let’s keep it simple.

Composite resins are basically made of 2 components:
(1) Fillers- are the solid inorganic materials
(2) Resins- are the liquid organic content

This is the Schematic Diagram of Fillers and Resins in A Microhybrid Composite.

There are other contents but this is not the time to discuss them as we are dealing with the shading factor of our restoration. The only reason I mentioned these 2 is because part of the shade of our final restorations get affected by the volume and size of these contents as we choose what type of composite resins we buy. These don’t only affect the shade but it is related in our handling, durability and polishability of our restorations. These 2 main components categorize the type of composite resins we should use in our restoration. They are the following:

(1) Hybrid
(2) Microhybrid
(3) Macrohybrid
(4) Nanohybrid
(5) Microfilled
(6) Sealants
(7) Flowable
(8) Luting Composites
(9) Resin-Filled
(10) Packable

So, that we don’t get confuse, I will not define first these categories because I will concentrate more on their importance when it comes to color shading which I believe, hopefully, all of us already have an idea on what they are. What we need to understand in terms of this category is when it is best to use them to get the right color shading and aesthetic value to our restorations.

First, we need to set our goals. One, I hope we are all in agreement that when it comes to Anterior Direct Restorations in the esthetic zone, we must match the tooth in fine detail as well as possess suitable physical characteristics and sufficient strength for function. While, Two, for Posterior Esthetic Direct Restorations, although, shade match with the tooth is still important, but, there are greater requirements for physical characteristics and strength due to the potential size and volume of some restorations as well as the stress-bearing nature of the posterior dentition.

So, now, that we know our goals, there are 3 Categories stated above that can be ideal in achieving aesthetic value for our anterior restorations: the Microhybrid, the Nanohybrid and the Microfilled. Why? Because the shape of the Filler content influences how light is transmitted and scattered. And, the volume of the Resin Contents versus the Volume, Size, and Shapes of the Fillers affect the polishability and durability of our restoration.

The Microfilled and Nanofilled will provide you the best polishability and aesthetic value because they contain microscopic filler particles that scatters light well. They have multifaceted particles that scatter and reflect light in different directions. Moreover, Nanofilled Composites transmit light more than other composites. Unfortunately, some of its durability and strength when force is applied in the stress bearing areas in the anterior teeth may not be as great in Microfilled even if it is the type of composite with higher level of polishability of all the types of composite resins especially in comparison to Microhybrid and Nanohybrid. A Microhybrid, on the other hand, is best for strength and durability when we are trying to achieve both aesthetic and durability in our restoration. In fact, studies show that Microhybrid composite restorations demonstrated better margins with lower leakage, staining and discoloration than Microfilled and Nanohybrid restorations. However, a Nanohybrid has better aesthetic value in comparison to a Microhybrid. FYI,  in addition, a Nanohybrid is actually under the category of Microhybrid before. It is actually called a sub-filled microhybrid. Wherein their fillers have the size and diameter equal or lesser than the size and diameter of our dentinal tubules and they are incorporated in higher volume to provide better strength. Therefore, Nanohybrid is best to use in Anterior Teeth with less stress-bearing areas while Microhybrid is best for Anterior Teeth with more stress-bearing areas. These 2 categories of Composite Resins will provide you better shade result as well as strength in your restorations.

II. The Anatomy of Your Tooth

We all know that the anatomy of our body are complex and different for each individual. Although, it is made and named of the same structures, there are idiosyncrasies that made it different from one person to another. That is the same with the anatomy of our tooth. That is why to simplify it as Shade A, B, C, or D is insufficient to get accuracy in choosing the right shade for our restorations. As mentioned in my part 1 in understanding how we look at colors, there’s a phenomenon that is called Metamerism, wherein two objects may appear to be identical colors under a certain kind of light yet under another kind of light they may appear totally different. The problem of Metamerism can be avoided by selecting a shade and confirming it under different lighting conditions, as mentioned as well in my Part 1 of this blog. In order delve better on how we can understand how our shade selection works, we need to know the key optical properties of the teeth that affects our shade selection which in turn should have the same features of the composite resin we use in our restorations, so, it can deliver the right result.

Key Optical Properties of Teeth:

1. Fluorescence is the absorption of light by a material and the spontaneous emission of light in a longer wavelength. Teeth are fluorescent because they emit visible light when exposed to Ultra-Violet light.

So why is it important to you?
Having a fluorescent effect similar to the natural tooth on the composite resin you will buy will allow your restoration to be undetectable. In vitro testing has found that there are considerable variations of fluorescence effect that can be found in different commercially available composites. So, when purchasing a composite resin, you should highlight the importance of you assessing and investigating the visual characteristics of the composite resin you are interested in buying.

2. Opalescence is the ability of a translucent material to appear blue in reflected light and red-orange in transmitted light. The opalescent effect is based on the behavior of translucency of natural teeth.

So why is it important to you?
Without Opalescence quality of your composite resin, your restoration will appear dull. Opalescence matching that of natural teeth is possible with composite resins. In fact, one study found the opalescence of tested direct composite resins to be more tooth-like than that of indirect composite materials or ceramics.

3. Translucency and Opacity- Translucency is transmission and diffusion of light through an object so that definite image beyond the object cannot be seen. Opacity is the total opposite of Translucency wherein the body is impervious to light.

So why is it important to you?
Translucency and Opacity are important concepts for shade selection. If a shade is selected does not mimic the translucency and opacity of the tooth, then, we  can expect that our restoration will look obvious and will not blend with the remaining tooth structure. In general, thinner layers are more translucent. And, the ability of the composite materials at a given thickness to provide opacity and translucency varies. Some requires greater thickness than others to block out dark objects such as the oral cavity behind the teeth. And, lesser thickness of composite placed if what you want to achieve translucency, such as would be required at incisal and proximo-incisal areas.

These key optical properties of the teeth should be present in the features of the composite resin you are buying. That’s why you can hear often enough these terms as a features and benefits of some high-end composites being sold in the market. This is also the reason why there are some shades and stains that can render these optical properties to mimic the tooth.

My Recommendations: In your clinic you need to have at least 4 variations of Composite Resins: Microhybrid, Nanohybrid, Flowable and Luting Composites. Why there's no sealants? In truth, Flowable composites are the best sealants. As long as your flowable composites contain continuous fluoride release, then, you are all set. In my book, Packable Composites, are the worst composite resins. If you are too lazy to do multi-layering technique in placement and curing, then, you are better off with a good Glass Ionomer.

Knowing and understanding the materials you are going to use in your restorations are very critical. Beside the price factor, terms of payment and promos to consider, we need first to understand why we are buying our composite resins in the first place. If you are the type of dentist who just wants to get it over with when it comes to treatments and really don’t care on the quality of work we render to our patients as long as we earn, then, this blog and the rest of my blogs are not for you. You will be just wasting your time reading them because doing restorations are really easy but doing it properly with considerations on how we do it and knowing and understanding the materials we use in order to achieve the result that is aesthetically sound and durable is all together a different matter. So, for those who are in quest to become better professional practitioners, I hope I have truly indeed help you in understanding better on how we can all achieve higher quality of work to our patients.

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