Modern resin composites—including nanohybrid and microhybrid types—have become the restorative dental material of choice due to their aesthetic superiority. However, in clinical practice, a major ongoing challenge is color stability. This article focuses on two key aspects:
- Development of resin composite recycling —how this innovation can extend lifespan while also supporting environmental sustainability.
- Color stability, particularly discoloration caused by exposure to staining agents such as coffee, and how external factors like temperature and immersion duration influence these changes.
Resin Composite Recycling
Recycling initiatives in dental resin composites remain limited, but findings from other polymer materials are promising. According to a review on polymer blends, mechanical and chemical recycling techniques have been shown to preserve the thermomechanical properties of materials, although challenges such as material compatibility still need to be addressed. Approaches such as the use of additives or compatibilizers are potential solutions to overcome structural degradation during the recycling process.
Color Stability of Resin Composites
UGM Study: Temperature and Duration Effects on Nanohybrid Resin
An experimental study at UGM conducted by Faculty of Dentistry student Aditya Krisna Murti, under the supervision of Dr. drg. Ema Mulyawati, M.S., Sp.KG(K) and Dr. drg. Tunjung Nugraheni, M.Kes., Sp.KG(K), examined color changes in nanohybrid resin composites immersed in coffee solution under two different temperature and immersion duration conditions. The results:
- Color changes in nanohybrid resin composites immersed in coffee solution at 54 °C were greater than those immersed at 4 °C, and
- Immersion for 4 days showed greater color change than immersion for 2 days.
This confirms that increased temperature and exposure duration significantly accelerate composite discoloration.
Other studies have shown that microhybrid resin composites exhibit better color stability than nanohybrid, particularly when immersed in colored beverages such as carbonated drinks. This is linked to the smaller filler particle size in nanohybrids, making them more susceptible to stain absorption.
Various clinical studies reveal that common staining agents—such as coffee, red wine, and carbonated beverages—cause significant color change (∆E) in resin composites. However, techniques such as repolishing have proven effective in correcting surface changes, thereby slowing color degradation.
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Color stability remains a significant challenge, particularly for nanohybrid resins that are more vulnerable to extrinsic stains and extreme conditions. Choosing hybrid or microhybrid materials and performing surface treatments such as periodic repolishing can enhance the aesthetic durability of restorations. Further research is recommended on adopting recycling techniques specifically for resin composites as well as developing new formulations with superior color stability.
References
Aditya Krisna Murti, Dr. drg. Ema Mulyawati, M.S., Sp. KG(K) ; Dr. drg. Tunjung Nugraheni, M.Kes., Sp.KG(K), Color Change in Nanohybrid Resin Composites Immersed in Coffee Solution at 4 °C and 54 °C with Different Immersion Durations, https://etd.repository.ugm.ac.id/penelitian/detail/156282
Author: Rizky B. Hendrawan | Photo: Freepik
