Polishing: The finishing touch on anterior composite restorations

Polishing is the last step of an anterior composite restoration. However, that does not mean it is not as foundational to the success of your restoration as the other steps that came before it. All of the stages of a composite restoration contribute to its success, and polishing has a significant impact on how the restoration will resist decay and integrate with the tooth surrounding it.

Polishing is making the surface smoother with abrasive materials. It requires excellent technique and an artistic touch to create the right look for your anterior composite restoration. You want a tooth that blends well with the others, has a proper amount of brightness, and a smooth surface.

“You are starting off with the coarser reduction of things in the finish, and polishing is the final step,” Jeff Lineberry, DDS, a general and cosmetic dentist who practices in Mooresville, N.C. says. “It’s like taking a diamond and then chipping away the rough edges; that’s the finish. The polish is getting everything just right.”

Polishing is not only esthetic, however. Polishing has clinical implications, as well. 

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“Polishing is one of those things that helps ensure the longevity of the restoration. The smoother it is, it doesn’t collect as much plaque. Also, it is less susceptible to stains and collecting other things around it,” Dr. Lineberry says.

General Dentistry points out polishing removes the surface irregularities that can contribute to staining, plaque buildup, gum irritation, caries, abrasive qualities,and wear kinetics.¹ Bacteria will adhere to rough surfaces, so surface roughness plays a significant role in deterring bacteria buildup.² Furthermore, when the surface roughness is higher than 0.2µ, studies show there are increases in secondary caries, gum irritation and, in cases of poor oral hygiene, gingival inflammation.³ Plus, patients can feel when it is not smooth enough.  

Insufficient polishing can also increase friction and wear to occlusal areas and opposing enamel, and eventually introduce microfractures into the composite surface.⁴ When you finish and polish correctly, you reduce the wear and marginal breakdown that can occur when the composite is too rough.

However, like all things in composite restorations, polishing is technique- and material-sensitive. Moreover, you determined some polishing success as soon as you reached for the type of composite you were going to use. Different particle and filler sizes affect the polishability of the composite.⁵

So, what are some ways you can get the best results from this final step? Here are some tips and tricks that might surprise you.

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Choose the right composite for the job

Composite resins have changed a lot over the past 60 years. Decreasing particle size, including innovative monomers, adding new material elements in the mix and modifying the photoinitiators allow today’s composite resins to have different physical characteristics. These characteristics make them suitable for anterior restorations.⁶ Per the Journal of Clinical Dental Research, you should choose materials for anterior teeth that block light or reflect it the way the surrounding teeth do, e.g., hybrids, microfills and nano-filled composites. ⁷

“A lot of the newer materials now, the nanofills and nanohybrids, were designed to be more of a universal composite; they have both strength and polishability,” Dr. Lineberry says. “In the grand scheme of things, as far as the polishability, microfills which have been around for a long time, have a very long clinical record as far as holding an enamel-like surface. But what we gain in polishability, we lose in overall strength.”

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Visualize the end before you begin

Dr. Lineberry advises clinicians to have the end in mind before you begin the restoration. Having a vision of what you want to achieve will drive your decisions and processes throughout the steps of composite restorations.

Consider how you are going to finish and polish the tooth. You have to look at all the overall contours and choose your approach as well.

Use the right finisher

Finishing happens right before polishing to removing excess material from your restoration. However, finishing systems use different elements that work in different ways to remove the excess.

Tungsten Carbide finishers cut away the material, and the number of blades will determine how abrasive it is. The more blades you have the smoother the finish.

Diamond finishers grind or mill the material away. The smaller the grit size of the diamond, the finer the abrasive quality.

Both kinds of finishers are suitable for composite restorations. However, the filler-type of composite you use will dictate which finishing tips will produce the best results. Per General Dentistry, for hybrids, you should use carbide finishers, for microfills and nanofills use a diamond finisher.⁸Also, your material manufacturer will likely have specific protocols for polishing that work best with their product as well.

“You can use a fine diamond or a super fine diamond on both materials,” Dr. Lineberry says of the nanofills and nanohybrids that many dentists use today. “Diamond finishers typically work better with nanofills because they are a harder material.”

Know your polishing tips

Finishers remove the excess material, but polishing tips finish the job by removing the scratches finishing instruments leave behind. While there are different polishing systems, most have four shapes, which include the small flame, large flame, cup and lens. Which one you use depends on what area you need to polish. Each tip has a specific job:

• Small Flame: Polishes delicate areas

• Large Flame: The all-around polishing tip; it works on all surfaces.

• Cup: Makes good contact with convex parts of the tooth

• Lens: Reaches proximal marginal ridges and spaces

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Dr. Lineberry likes to use a lot of polishing discs when polishing a contour in anterior restorations. He uses discs on the front, the edges and the sides of anterior restorations. However, in other areas, he uses a different approach.

“On the lingual aspect of the tooth, which is a little more challenging, a lot of times I am going to use a point polisher or an egg-shaped fine diamond there,” Dr. Lineberry explains.

Leave enough time to polish

Composite restorations have many steps that build upon one another to create restorations with the physical and esthetic properties you want. However, each one takes time for proper outcomes. As the last step, you might find yourself facing the time to polish with no time left in the schedule. If you find you often feel rushed during polishing, it might be time to review other inefficiencies in your process with your assistant. If there is a consistent step giving you problems, troubleshoot it until you have it as efficient as possible. Another solution could be to add a standing order to pad anterior restorations by at least 15 minutes to allow for enough time to polish the composite resin as you intended.

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Begin at the beginning

Dr. Lineberry suggests starting with the most coarse polishers and work your way to the finer ones. Sometimes people start in the middle, he says, but when you start with a coarse reducer, it improves the overall finish more than when you skip the early reducers.

“I use one of Cosmedent’s products called FlexiDisc. It’s a felt polishing wheel with an aluminum oxide impregnated polishing paste. Using that for the final step brings out the final shine,” Dr. Lineberry says. “But also, patients say they don’t feel texture to their teeth anymore. They feel like it’s just part of the tooth.”

Find the polishing system that works best in your hands 

Some research suggests to get the best polish, you should use the polishing system of the manufacturer of your composite. The idea behind this approach is  the manufacturer knows what is best for their materials. Dr. Lineberry says in reality, a manufacturer might have excellent material, but their polishing system isn’t the best, or vice versa.

“I use cross manufacturers all the time,” Dr. Lineberry says. “I think you have to find a system that works best in your hands.”

What “works best in your hands” will come from experience. Dr. Lineberry recommends going to continuing education sessions and doing hands-on courses to try different things to get that experience.

“At a lot of the courses you are using a variety of materials and polishing systems that give you exposure to what may work for you,” Dr. Lineberry says

References

¹ LeSage, DDS, FAGD, FAACD, Brian. “Finishing and polishing criteria for minimally invasive composite restorations.” General Dentistry. 2011 Nov-Dec; 422-428; Accessed via web. 21 July 2019. <https://pdfs.semanticscholar.org/01f9/329480a6b9e8ac481dd57210c56b508d7542.pdf

>.

² Ibid.

³ Ibid.

⁴ Ibid.

⁵ Ibid.

⁶ Kabbach W, Gedeon FBD, Arita C. Finishing and polishing in composite resin restorations: from macro to micro. J Clin Dent Res. 2016 jan-mar;13(1):121-31.

Accessed via web: 20 July 2019. <https://pdfs.semanticscholar.org/d3c1/3468e1b0c75947cfb888f634e5b2db24f55f.pdf>

⁷ Ibid.

⁸LeSage, DDS, FAGD, FAACD, Brian. “Finishing and polishing criteria for minimally invasive composite restorations.” General Dentistry. 2011 Nov-Dec; 422-428; Accessed via web. 21 July 2019. <https://pdfs.semanticscholar.org/01f9/329480a6b9e8ac481dd57210c56b508d7542.pdf