Re: how long do they last?



Dr.Braces wrote:
I am wondering from other dentists in the group what is the average life expanceity of an well placed..

4 surface posterior amalgam
4 surface posetrior composite
gold posterior onlay


I am not placing that many these days as I am an orthodontist, however I guess

15-20 years
5-7 years
15-35+ years



There are of course too many variables to give any but a general impression. I have seen even large amalgams last as long as 50 years. However, most of these were not only carefully placed but carefully polished--something few of us do anymore. Careful polishing seems to greatly enhance long-term marginal integrity.
Of course, if a patient has significant caries activity (they must have needed that 4-surface restoration for a reason, right?) the restoration longevity is usually limited by recurrent decay, not by gross failure of the restoration itself.
I have on occasion done large resin buildups or restorations. If I do, it is usually because a patient cannot afford a crown or inlay. I tell patients that I do not expect it to last forever, and that they should expect they will be needing a crown eventually. I have seen some of these hold up so far for several years, but large resin restorations in my office fail more frequently than amalgams of the same size. I have seen occasional patients with old (over 10 years) resin restorations that have held up marginally; many of these show significant occlusal wear. However, there has been improvement in the resins over time, so I would expect improving marginal and occlusal properties.
I would only add that (as you might expect) resin restorations ending interproximally on dentin have a terrible incidence of failure due to recurrent decay--I don't care what generation bonding agent you use.
I've never done a large number of gold inlays/onlays. It may be patially an East Coast--West Coast difference. Most of my patients with extensive caries--I don't want to give them an expensive gorgeous restoration with miles of supragingival margins. However, when these work, they work essentially forever.

Steve

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