Most common cause of chipped porcelain in PEM:
- a- Thin layer of metal
- b- Thin layer of porcelain
- c- Centric occlusal contact at the junction of porcelain and metal.***
The most common cause of chipped porcelain in porcelain-fused-to-metal (PFM) crowns is c) Centric occlusal contact at the junction of porcelain and metal.
Here's why:
- Thin layer of metal:
While a thin metal layer can potentially contribute to chipping if it weakens the overall structure of the crown, it's not the primary culprit. Most PFM crowns have sufficient metal thickness to withstand normal chewing forces.
- Thin layer of porcelain:
Similar to the metal layer, a thin porcelain layer might make the crown more susceptible to chipping due to reduced strength. However, modern PFM techniques generally involve optimal porcelain thickness for durability.
- Centric occlusal contact at the junction of porcelain and metal:
This is the most likely cause of chipping due to the concentrated stress placed on the crown at this transition point. The different physical properties of metal and porcelain can create a weak spot where chipping is more likely to occur, especially under heavy biting forces.
Additional Factors:
Here are some additional factors that can contribute to porcelain chipping in PFM crowns:
- Improper bite alignment:
If the teeth don't come together properly, excessive force can be concentrated on certain areas of the crowns, increasing the risk of chipping.
- Grinding or clenching teeth:
These habits can put significant strain on the crowns, making them more prone to damage.
- Trauma:
Physical impact to the teeth, such as from a fall or accident, can cause chipping or even complete fracture of the crown.
If you experience chipped porcelain in your PFM crown, it's important to consult your dentist as soon as possible. They can assess the damage and determine the best course of treatment, which may involve repair, replacement, or other options.
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