3 Common Technique Mistakes That You Should Avoid When Placing Composite Restorations

By Kzenon / stock.adobe.com

Composite restorations require a detailed eye for technique. However, it would help if you also kept an eye out for these common technique mistakes: Failing to isolate, having poor layering technique, and allowing for insufficient curing. Each of these common mistakes can lead to problems with your restorations, up to and including restorative failure. We will look at each and how you can avoid them.  

Mistake #1: Failing to achieve field control.  

 For the best possible outcome for the restoration, it is essential to have a preparation that sets you up for success. For bonding, it is crucial to have as pristine an environment as possible for the bonding agent. When you fail to isolate the preparation and control the fluid, you invite post-operative sensitivity, contamination, and microleakage to destroy your restoration. Moreover, it is not OK to have it "mostly" isolated. The field needs to be 100% clean and dry.

Which type of isolation you choose depends on several variables. The College of Dentistry and Dental Clinics for the University of Iowa lists them as:¹ 

• Tooth size, shape, and position
• Tissue position and health
• Lesions' position and size
• Patient facial anatomy
• Patient cooperation and desires

The Rubber Dam is the "gold standard," per the university because it can effectively achieve the field control necessary to achieve a quality restoration. But supposing a rubber dam is not possible, they recommend alternative methods of isolation, including lip and cheek retractors, cotton, and cotton roll holders, Isolite, Hygroformic Saliva evacuation, and retraction cord, and hemostatic agents. However, they do caution clinicians that hemostatic agents can interfere with the bonding agent.¹

Whether they are the gold standard or not, many dentists do not like rubber dams and do not use them once they leave dental school. An excellent option is to train your dental assistant to place them for you. However, it is a good idea to check with your state board to ensure that your dental assistant can set up rubber dams there. 

Mistake #2: Not moving the curing light around during curing.

Polymerization of composite resin is crucial to the success of your restorations. Without proper curing technique, your restoration could have excessive polymerization shrinkage, reduce mechanical properties of the material, increase the residual monomers that can damage the tooth restoration, increase the occurrence of surface staining, and the chances of marginal leakage.²

The dental light itself and light-curing technique can cause insufficient polymerization. For the dental curing light, the beam profile, tip size, and guide angle of your light affect the size of the light-curing area:³

•  Beam profile: Every curing light has a beam profile, which describes how the light distributes from the tip. Most curing light manufacturers want a uniform beam profile, but sometimes the curing light has more intense areas for irradiance than others. When the beam profile is not consistent, it can affect the microhardness of resin-based composites that could lead to premature failure of your dental restoration.v Suppose you move the light around the material during curing. In that case, you also move those more intense areas across the curing surface, ensuring that the entire area has its time to activate the photoinitiator.
• Tip size: The tip size dictates where the active curing area is when using the light. In other words, the smaller the tip, the smaller the curing area. If you have a larger curing area, you need to use a light with a larger tip or overlap the active curing area to ensure that all the surfaces get the light. 
• Guide Angle: The guide angle affects where the curing light tip can fit in the mouth and, subsequently, where the active curing area lands. So, if the guide angle does not fit, it can obstruct the lights' ability to reach the curing area. To get there, you might have to approach the restorative material's surface area from the opposite direction to light cure all the material. 

If you use a technique that does not account for these influences from your curing light, then you could end up with under-cured material and all the problems that go with it. By moving the curing light around the uncured restorative material in the oral cavity, you could help reduce the chances of insufficient polymerization.

 Mistake #3: Polishing too much.

Polishing is the last step of the restoration, but that does not decrease its importance in the composite resin restorative process. The polishing step not only makes the tooth feel smooth but also sets up the longevity of your restoration. Polishing the surface creates a more resistant plane to bacteria, staining, plaque buildup, and wear kinetics. Also, studies show if you do not reduce surface roughness enough, patients present with secondary decay, gum irritation, and inflammation. In addition, the friction and occlusal and opposing dentition wear can introduce microfractures into the surface.⁴ 

However, polishing is another critical area that could be prone to errors. Unlike the curing mistake where you do not get enough, polishing too much can cause many problems with the material. Per the IJRD, polishing too much can build up heat, which changes the resin matrix, disrupts the post-irradiation phase of polymerization, and takes off the layer that likely has the best conversion. You also increase the risk of pulp injury by excessive heat.⁵

The IJRD suggests ensuring that you plan for the restoration before you begin to optimize your polishing time. If you pack in too much material and then use the polish step to remove the excess, you could create an unfavorable condition for your composite's restorative success. The IJRD also suggests exercising caution with your burs to avoid damage to the margins and surrounding dentition. Preserving these crucial areas of your dental restoration helps deter the failure of the tooth/restoration interface.⁵ 

In addition, you should leave enough time to polish. You have probably heard the saying, "haste makes waste," which holds if you rush the polishing step to make room for the next patient on the schedule. If you often feel squeezed for time at this point in the restorative process, try extending the amount of time you schedule for composite restorations by 10-15 minutes and see if that fixes the problem. While production rate is an essential metric to optimize for profitability in many dental practices, the extra time you add into the schedule for composite resin restorative treatments could make the difference between a restoration that lasts for several years and a restoration that you must fix in a few months for free

References

1. Dentistry.uiowa.edu. n.d. operative-field-control | College of Dentistry and Dental Clinics. [online] Available at: <https://www.dentistry.uiowa.edu/operative-field-control> [Accessed 18 June 2021].

2. de Camargo EJ, Moreschi E, Baseggio W, Cury JA, Pascotto RC. Composite depth of cure using four polymerization techniques. J Appl Oral Sci. 2009;17(5):446-450. doi:10.1590/s1678-77572009000500018

3. "9 Ways Your Dental Curing Light Could Be Putting Composite Restorations at Risk." bluelightanalytics.com. 8 June 2021. Web 18 June 2021. < https://www.bluelightanalytics.com/resources/blog/9-risks-dental-curing-lights-composite-restorations>.

4. 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

5. Porto, Ph.D. I. (PDF) Post-operative sensitivity on direct resin composite restorations: clinical practice guidelines. ResearchGate. https://www.researchgate.net/publication/235977564_Post-operative_sensitivity_on_direct_resin_composite_restorations_clinical_practice_guidelines. Published 2012. Accessed June 19, 2021.