Amalgam fillings, often referred to as silver fillings, have been widely used for many years due to their durability and strength. However, one significant downside of amalgam is its potential to cause cracks in teeth over time. This happens due to a combination of factors related to the properties of the material and its behavior inside the mouth.
1. Expansion and Contraction with Temperature Changes
Amalgam fillings tend to expand and contract when exposed to temperature fluctuations, such as when consuming hot or cold foods and drinks. This thermal expansion can put stress on the surrounding tooth structure. Over time, the repeated expansion and contraction may create micro-fractures in the tooth. As these fractures grow, the tooth becomes more vulnerable to larger cracks, which can eventually lead to tooth weakening or breakage.
2. Metal Rigidity
Amalgam is a relatively rigid material compared to the natural flexibility of the tooth. While your natural tooth structure can absorb and distribute pressure, amalgam fillings do not distribute force evenly. Instead, they concentrate pressure in specific areas of the tooth. With continuous biting and chewing forces, particularly on back teeth (molars), this concentrated stress can cause cracks to develop.
3. Large Fillings Increase the Risk
Amalgam is often used in larger cavities because of its strength. However, in large fillings, more of the natural tooth structure is removed, which can already weaken the tooth. When you add the expansion-contraction behavior of amalgam to a compromised tooth, the risk of cracking increases further. In fact, many patients with old, large amalgam fillings may experience fractures around the filling over time.
4. Crack Development Over Time
Cracks caused by amalgam fillings often start small and may not be immediately noticeable. In some cases, you may not feel any symptoms until the crack becomes severe enough to affect the tooth’s integrity. At this point, the tooth may become sensitive, especially to biting pressure or temperature changes, and could eventually break or require more extensive treatments like crowns or root canals.
What Can Be Done?
If you have amalgam fillings, regular dental check-ups are essential to monitor for any signs of cracking or weakening around the fillings. Your dentist can spot early signs of stress on your teeth and recommend treatment before more severe damage occurs.
For teeth that have developed cracks or are at risk of further damage, a dental crown is often the best treatment option rather than replacing the filling with composite or ceramic materials. A crown provides full coverage and protection to the weakened tooth, helping to prevent further cracking and damage. It encases the entire tooth structure, offering significantly more strength and durability compared to fillings.
Why a Crown Is Preferable Over a Filling
- Full Tooth Protection: Unlike composite or ceramic fillings that only fill a portion of the tooth, a crown completely covers the tooth, providing comprehensive protection against cracks and breaks.
- Durability: Crowns are typically much more durable than fillings and can last many years, even under the heavy pressure of chewing, making them ideal for molars or large cavities.
- Prevents Further Damage: Once a tooth has started to crack, filling materials alone may not provide enough reinforcement. A crown stabilizes the tooth and prevents the crack from spreading or causing more serious damage, such as tooth fracture or the need for extraction.
Conclusion
While amalgam fillings are durable, they can lead to cracks in teeth due to their expansion-contraction behavior and rigidity. For teeth at risk of cracking or those already showing signs of damage, opting for a dental crown is often the most effective solution. A crown provides complete protection, preventing further damage and ensuring the longevity of your tooth, particularly in cases where a filling may no longer be sufficient. If you have concerns about your amalgam fillings or cracked teeth, speak with your dentist to determine whether a crown might be the right option for you.