Posted in | News | Composites

Testing the Degree of Pigment Penetration in Composite Resins

Composite resins are the preferred material for dental surgical restorations due to their pleasing aesthetic and structural qualities. Giachetti et al. have published research in the journal Materials that aims to determine the extent of color infiltration into composite resins to resolve the problem of discoloration.

Study: Stain Susceptibility of Composite Resins: Pigment Penetration Analysis. Image Credit: Meaw_stocker/Shutterstock.com

Significance of Composite Resins

Composite resins are widely used for dental restorations in both anterior and posterior teeth. This is because these polymers have both pleasing aesthetic and structural qualities, enabling a minimally invasive approach. The color stability and exterior refining and polishing of resin composite implants are critical to their success.

Test groups specimens preparation.

Test groups specimens preparation. Image Credit: Cinelli F. et al., Materials

Failure Causes in Composite Resins

One of the most typical reasons for composite resin recovery failure is discoloration and borderline spots.

Discoloration produces color disparity, leading to patient discontent and increased costs for restorative correction/replacement. External factors or intrinsic causes can induce discoloration of resin-based substances. Extrinsic influences include colorant absorption as a result of impurities from environmental factors. Exterior discolorations in resin composites are associated with cleanliness, dietary habits, and smoking habits.

The intrinsic factors include discoloration of the composite resin, as well as changes in the matrix material and the boundary between the substrate and the additives.

Factors Affecting Discoloration and Color Stability

The internal factors include discoloration of the composite resin themselves, as well as changes in the resin matrix and the boundary between the substrate and the additives. Color durability of resin composites is precisely correlated to the particle size of granules, variety, quantity, substrate and polymer category, degree of polymerization, and water permeability.

Materials Utilized

The study examined two commonly available composite resins. The first one is a nano-filled composite resin and the second one is a non-homogeneous micro-hybrid composite resin. The samples were created using a tubular polypropylene mold with a diameter of 2.0 mm and an inner diameter of 8.4 mm.

The image shows a schematic representation of different measurement levels.

The image shows a schematic representation of different measurement levels. Image Credit: Cinelli F. et al., Materials

Research Findings

This research looked at 80 samples created from two distinct types of composite resins. The test groups were aged for 15 days by immersing them in a coffee beverage solution at 37 °C. For the duration of the study, control group samples were soaked in physiologic solution at 37 °C.

The color assessment was carried out using the CIELab methodology, and the W (whiteness) factor was determined for each location. Based on CIELab data, W is an independent whiteness index. The W values of the two composite resins submerged in the physiological fluids follow a consistent trend and show no vibrant colors at any measurement level.

As Filtek Supreme composite resin was pigmented, it changed color significantly up to 1mm in depth when contrasted to the same resin maintained without chromogenic ingredients. The EvoCeram composite resin, on the other hand, changed statistically significantly until 2 mm. Filtek Supreme appeared to be more stain-prone, most likely due to its nano-aggregated crystalline structure.

How to Restore Natural Color

When the coloring of the composite becomes clinically undesirable, the original color must be restored. One method would be to eliminate the restoration's outer surface and replace it with new material. Otherwise, the overall restoration must be replaced. The potential of recovering the original color of the resins by using bleaching agents is also quite appealing.

Limitations

Owing to the aims of the research, some limitations must be addressed. The use of a scanner to analyze the samples may result in a mistake. In reality, the data show that even the control groups have whiter exterior levels, but the inside component has a higher W value. The existence of the white plaster cast, which may reflect back light and influence the coloration of the exterior sections, could be one plausible cause.

In any event, this would be a systemic mistake that would affect both the test and control groups.

The image shows the trend of W for each group. It can be observed that, in the more superficial levels of the specimens, the groups show different values, while, moving towards the center of the specimens, the values tend to become uniform.

The image shows the trend of W for each group. It can be observed that, in the more superficial levels of the specimens, the groups show different values, while, moving towards the center of the specimens, the values tend to become uniform. Image Credit: Cinelli F. et al., Materials

Future Perspective

Although there is a significant amount of research on the pigmentation of composites, the process of discoloration might be investigated further. It is unclear if color accumulation happens solely on the exterior or if it occurs inside the substance, and if so, to what amount. However, it is essential to explore this issue so that the discoloration may be effectively addressed.

To summarize, the two composite resin substances that were pigmented suffered color fluctuation with distinct patterns. On the surface, the Filtek Supreme composite was demonstrated to be more susceptible to color variations than the EvoCeram composite.

Further Reading

Cinelli F. et al. (2022). Stain Susceptibility of Composite Resins: Pigment Penetration Analysis. Materials. 15(14). 4874. Available at: https://www.mdpi.com/1996-1944/15/14/4874

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.

Ibtisam Abbasi

Written by

Ibtisam Abbasi

Ibtisam graduated from the Institute of Space Technology, Islamabad with a B.S. in Aerospace Engineering. During his academic career, he has worked on several research projects and has successfully managed several co-curricular events such as the International World Space Week and the International Conference on Aerospace Engineering. Having won an English prose competition during his undergraduate degree, Ibtisam has always been keenly interested in research, writing, and editing. Soon after his graduation, he joined AzoNetwork as a freelancer to sharpen his skills. Ibtisam loves to travel, especially visiting the countryside. He has always been a sports fan and loves to watch tennis, soccer, and cricket. Born in Pakistan, Ibtisam one day hopes to travel all over the world.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Abbasi, Ibtisam. (2022, July 18). Testing the Degree of Pigment Penetration in Composite Resins. AZoM. Retrieved on August 18, 2022 from https://www.azom.com/news.aspx?newsID=59570.

  • MLA

    Abbasi, Ibtisam. "Testing the Degree of Pigment Penetration in Composite Resins". AZoM. 18 August 2022. <https://www.azom.com/news.aspx?newsID=59570>.

  • Chicago

    Abbasi, Ibtisam. "Testing the Degree of Pigment Penetration in Composite Resins". AZoM. https://www.azom.com/news.aspx?newsID=59570. (accessed August 18, 2022).

  • Harvard

    Abbasi, Ibtisam. 2022. Testing the Degree of Pigment Penetration in Composite Resins. AZoM, viewed 18 August 2022, https://www.azom.com/news.aspx?newsID=59570.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this news story?

Leave your feedback
Your comment type
Submit