For many years, Porcelain-fused-to-metal (PFM) crowns were the solution for attractive restorations. Ceramic wasn’t yet strong enough by itself, so a thin layer of porcelain was bonded to a metal structure in the hope that it would function as a durable, and natural looking replacement for damaged teeth.
In reality, however, PFM proved to be less than optimal in both these aspects.
The Porcelain Is Too Thin
PFM crowns were initially designed to utilize natural looking ceramic and durable metal to provide patients with a long-term solution to damaged teeth. Instead, the porcelain overlay proved to be too thin, often cracking, chipping, or flaking off, exposing the unattractive metal underneath.
Worse, the metal was not designed to function on its own. Once it has been exposed to the elements, it can often wear, putting the tooth at risk.
Due to their construction, an unfortunate drawback of PFM crowns is that the metal understructure can be seen at the gum line. In a perfect world, this border would be concealed.
The problem is that many patients experience receding gums after their crowns. One possible explanation is the increased risk of gum disease with age. Another, however, may be related to the metal crowns themselves, which can irritate gum tissue and cause inflammation that may lead to gum recession.
Natural Tooth Translucency
Natural teeth have a special kind of translucency created by our enamel. In general, ceramics do a fantastic job simulating this coloration, but when the ceramic is thin and fused against a layer of metal, this can create an unnatural effect in certain light. This makes your restored teeth visible, defeating the purpose.
What’s the Solution?
There are several types of crowns to choose from: PFM, metal, or porcelain. Metal has its own advantages. They’re durable and they work well with natural teeth. Ideally, they are chemically inert so not generally harmful, but many people experience issues, especially when they have multiple metals present in their mouth. And they are highly visible when you smile.
Considering current dental technology, porcelain crowns seem to be the best solution to replacing PFM crowns. Unlike several years ago, ceramics are now strong enough to function as a full crown. They look much more natural, and can even insulate against temperature better than metal alternatives.
While some disadvantages still exist for all-porcelain crowns, such as price, these can be worked out best by scheduling an appointment and speaking with your dentist.