Amalgam & Composite:Which Lasts longer?!?!

[DentPursuer88]

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Hey guys, I am sure there are enough well experienced dentists who can help me with this question.

Basically, I had an argument with my teacher in dental assisting school. I tried to answer a question for a student saying that amalgam usually lasts longer than composite. Amalgam's life span can range from 20-30 years "if delivered well" and composite can last up to 10-15-20 years if delivered appropriately. She said "Mr. Bakkar, I totally disagree with you. In fact, composite lasts just as long as amalgam, if not better and longer." I was shocked and felt stumped. I talked to my dentist, and he agrees with me.

So what's the deal? Is there more information I am missing? I know that micro leakage can occur both in composite and amalgam restoration, yet they appear more in amalgam. Also amalgam isn't technique sensitive while composite is. One more question. Why do amalgams have more OPEN MARGINS than composite? Does it have to do with the bonding or material?

Thank you for your time.

 

[harjay]

well I'm only pre-dental, but for some reason I feel qualified to answer this question.
Amalgams typically do last longer than composites. Of course the range for each can vary based on how well they were made and taken care of, but this is one of the major reasons amalgams are still used today.

The amalgam material is closer in thermal expansion properties to enamel than composite is. For example, if you ate ice cream both the filling and the enamel will contract/shrink a little bit. The composite will shrink slightly more than the tooth enamel, but amalgam matches the enamel almost perfectly. Amalgams obviously don't have to be etched, bonded, and cured into/onto the teeth, but if they are placed correctly, they will be secured in place from when they were set.

I don't know about the margins, but I would assume it's because the amalgam isn't bonded to the teeth. I think that when the amalgam is set, it expands slightly and this holds it in place. This would not keep small edges or margins from being pulled back or worn away.

Ask your teacher why amalgams are still used today. The fact that they last longer is such a big part of why they are still used- I think she may not have strong arguments to answer that.

 

[Dentisting]

I have a question.... What are the disadvantages of using amalgam compared to composite?

Or maybe I should be asking... what are the advantages of using composite... besides looking more like your actual teeth.

 

[jdoc04]

I asked my wife who is a 4th yr dental student. She says they are taught that composite can last as long as an amalgam filling and the research proves so but the "X" factor is technique. Composites are very technique sensitive. Depending on the situation amalgam may be the better treatment option b/c of the this.

 

[zthang]

Composite life is getting better these days.
But I'd say amalgam...done right it could last longer than you'd probably live.

 

[Mcglock]

I have to agree with jdoc04 about technique. Composites usually don't last as long as amalgam because dentists prep the tooth the same for a composite as they would for an amalgam, when they should be prepping it specifically for the composite. At least this is what I heard at a CE course about prepping teeth for composites.

 

[DentPursuer88]

thanks for all the information guys....it helped me out a lot!

 

[djeffreyt]

Technique sensitivity is the key. A perfectly completed amalgam and a perfectly completed composite in the exact same mouth could both last the life of the patient and the only major reason for failure of composites earlier nowadays is the technique for composites to be perfect is more difficult to achieve clinically.

I have a question.... What are the disadvantages of using amalgam compared to composite?

Or maybe I should be asking... what are the advantages of using composite... besides looking more like your actual teeth.

Well, composites require a less invasive preparation style than amalgams usually require thus conserving tooth structure...