Fractured Porcelain on crown 
Author Message
 Fractured Porcelain on crown

Several years ago, I had to add a permanent bridge to my dental picture.

The bridge consists of 2 crowned teeth (which were good) and an attached
pontic.  The bridge is located on the lower side of my mouth just in front
of the last molar. The pontic is over that space just before the last
molar. [NOTE:  I have no wisdom teeth.]

Several months ago, I noticed that the covering of the middle crown was
chipped on the side near my lips and had a visible fracture line across the
top.  My dentist held off trying to repair it inasmuch as I was going
thru dental surgery [had a tooth pulled] on the lower left side of my mouth.
He didn't want to introduce any acid to my mouth until the healing
process had taken hold.

I have had other crowns in my mouth for many more years than the one that
is currently damaged.  Nothing like this has every occurred before.  My
dentist indicated that though rare porcelain has been known to crack.  My
other crowns are covered with enamel which he says doesn't.

For the past two weeks, he has been preparing the crown for bonding which
he did this afternoon.  I waited about 5 hours before trying to eat
anything and when I did bite into a very soft cookie the bonding came off
immediately. I knew that it had immediately inasmuch as I was aware of
some type of pressure when I bit into the cookie.  

Now I am convinced more than ever that the workmanship on the original
bridge was faulty and that probably the bonding procedure will not work.

I questioned him on this and he again referred to problem with porcelain.
I then ask, why did they use it on a biting surface?

Has anyone had any experience with this type of problem?

What is the solution?



Sat, 30 Jan 1999 03:00:00 GMT
 Fractured Porcelain on crown

Quote:

>Several years ago, I had to add a permanent bridge to my dental picture.
>The bridge consists of 2 crowned teeth (which were good) and an attached
>pontic.  The bridge is located on the lower side of my mouth just in front
>of the last molar. The pontic is over that space just before the last
>molar. [NOTE:  I have no wisdom teeth.]
>Several months ago, I noticed that the covering of the middle crown was
>chipped on the side near my lips and had a visible fracture line across the
>top.  My dentist held off trying to repair it inasmuch as I was going
>thru dental surgery [had a tooth pulled] on the lower left side of my mouth.
>He didn't want to introduce any acid to my mouth until the healing
>process had taken hold.
>I have had other crowns in my mouth for many more years than the one that
>is currently damaged.  Nothing like this has every occurred before.  My
>dentist indicated that though rare porcelain has been known to crack.  My
>other crowns are covered with enamel which he says doesn't.
>For the past two weeks, he has been preparing the crown for bonding which
>he did this afternoon.  I waited about 5 hours before trying to eat
>anything and when I did bite into a very soft cookie the bonding came off
>immediately. I knew that it had immediately inasmuch as I was aware of
>some type of pressure when I bit into the cookie.  
>Now I am convinced more than ever that the workmanship on the original
>bridge was faulty and that probably the bonding procedure will not work.
>I questioned him on this and he again referred to problem with porcelain.
>I then ask, why did they use it on a biting surface?
>Has anyone had any experience with this type of problem?
>What is the solution?

The solution is simply remake the bridge.  The porcelain repairs I
have seen are ghastly.  I usually have the biting surface in metal if:
there is no room for porcelain (you need at least 1 1/2 mm of
porcelain thickness); the patient is a grinder/bruxer; or if the
patient has metal crowns opposing the one to be restored.  I would
suggest finding a dentist you trust to remake the bridge.  Dr. Jeff W.


Sun, 31 Jan 1999 03:00:00 GMT
 Fractured Porcelain on crown

Porcelain is usually very durable, even on biting surfaces of crowns and
bridges, and your dentist is correct in stating that it is rare when it
fractures.  When it does, it's a hassle to fix, because it is difficult,
but possible, to bond composite to porcelain and/or metal, especially
under chewing loads.

The main causes of porcelain fracture in my experience is (1) the metal
framework under the porcelain not rigid enough, allowing flexure, causing
the porcelain to pop off.  That is why it can happen more frequently on
bridges as opposed to single crowns;  (2) during the addition and firing
of the porcelain in the lab, stresses due to temperature changes or
porcelain contamination can cause it to weaken; and (3) if the bite was
off and/or you clench or grind your teeth excessively.  This last
possibility is by far the least likely, but it has happened.

Unfortunately, unless the repair holds, the only remedy is to remake the
bridge.  In our office, if the bridge was recently made, it is remade at
no charge; if it has been in a moderate amount of time, I usually reduce
the fee commensurate with the longevity.  If it's been there awhile, tough
toenails, it's time for a new bridge!

Sorry that happened, and I hope this helped.

Grant Ritchey


writes:

Quote:
>Several years ago, I had to add a permanent bridge to my dental picture.

>The bridge consists of 2 crowned teeth (which were good) and an attached
>pontic.  The bridge is located on the lower side of my mouth just in
front
>of the last molar. The pontic is over that space just before the last
>molar. [NOTE:  I have no wisdom teeth.]

>Several months ago, I noticed that the covering of the middle crown was
>chipped on the side near my lips and had a visible fracture line across
the
>top.  My dentist held off trying to repair it inasmuch as I was going
>thru dental surgery [had a tooth pulled] on the lower left side of my
mouth.
>He didn't want to introduce any acid to my mouth until the healing
>process had taken hold.

>I have had other crowns in my mouth for many more years than the one that
>is currently damaged.  Nothing like this has every occurred before.  My
>dentist indicated that though rare porcelain has been known to crack.  My
>other crowns are covered with enamel which he says doesn't.

>For the past two weeks, he has been preparing the crown for bonding which
>he did this afternoon.  I waited about 5 hours before trying to eat
>anything and when I did bite into a very soft cookie the bonding came off
>immediately. I knew that it had immediately inasmuch as I was aware of
>some type of pressure when I bit into the cookie.  

>Now I am convinced more than ever that the workmanship on the original
>bridge was faulty and that probably the bonding procedure will not work.

>I questioned him on this and he again referred to problem with porcelain.
>I then ask, why did they use it on a biting surface?

>Has anyone had any experience with this type of problem?

>What is the solution?



Sun, 31 Jan 1999 03:00:00 GMT
 Fractured Porcelain on crown

Quote:

> Porcelain is usually very durable, even on biting surfaces of crowns and
> bridges, and your dentist is correct in stating that it is rare when it
> fractures.  When it does, it's a hassle to fix, because it is difficult,
> but possible, to bond composite to porcelain and/or metal, especially
> under chewing loads.

> The main causes of porcelain fracture in my experience is (1) the metal
> framework under the porcelain not rigid enough, allowing flexure, causing
> the porcelain to pop off.  That is why it can happen more frequently on
> bridges as opposed to single crowns;  (2) during the addition and firing
> of the porcelain in the lab, stresses due to temperature changes or
> porcelain contamination can cause it to weaken; and (3) if the bite was
> off and/or you clench or grind your teeth excessively.  This last
> possibility is by far the least likely, but it has happened.

> Unfortunately, unless the repair holds, the only remedy is to remake the
> bridge.  In our office, if the bridge was recently made, it is remade at
> no charge; if it has been in a moderate amount of time, I usually reduce
> the fee commensurate with the longevity.  If it's been there awhile, tough
> toenails, it's time for a new bridge!

> Sorry that happened, and I hope this helped.

> Grant Ritchey


> writes:

> >Several years ago, I had to add a permanent bridge to my dental picture.

> >The bridge consists of 2 crowned teeth (which were good) and an attached
> >pontic.  The bridge is located on the lower side of my mouth just in
> front
> >of the last molar. The pontic is over that space just before the last
> >molar. [NOTE:  I have no wisdom teeth.]

> >Several months ago, I noticed that the covering of the middle crown was
> >chipped on the side near my lips and had a visible fracture line across
> the
> >top.  My dentist held off trying to repair it inasmuch as I was going
> >thru dental surgery [had a tooth pulled] on the lower left side of my
> mouth.
> >He didn't want to introduce any acid to my mouth until the healing
> >process had taken hold.

> >I have had other crowns in my mouth for many more years than the one that

> >is currently damaged.  Nothing like this has every occurred before.  My
> >dentist indicated that though rare porcelain has been known to crack.  My

> >other crowns are covered with enamel which he says doesn't.

> >For the past two weeks, he has been preparing the crown for bonding which

> >he did this afternoon.  I waited about 5 hours before trying to eat
> >anything and when I did bite into a very soft cookie the bonding came off

> >immediately. I knew that it had immediately inasmuch as I was aware of
> >some type of pressure when I bit into the cookie.

> >Now I am convinced more than ever that the workmanship on the original
> >bridge was faulty and that probably the bonding procedure will not work.

> >I questioned him on this and he again referred to problem with porcelain.
> >I then ask, why did they use it on a biting surface?

> >Has anyone had any experience with this type of problem?

> >What is the solution?

The only thing that I might add, is that I have used an air-abrasion
unit to prep the porcelain/metal for bonding with much greater success
than any other technique.

SWF DDS



Sun, 31 Jan 1999 03:00:00 GMT
 Fractured Porcelain on crown

There can be several reasons for porcelain fracture on a porcelain fused
to metal crown or pontic.  The most common is an inadequate thickness of
porcelain on the metal resulting in a weak bond to metal  and a low
resistance to porcelain to the strong biting forces in the mouth.  The
dentist should have determined the clearance for the vertical clearance
when preparing the bridge and the laboratory should have cut back the
metal to allow adequate thickness.  Either of these infractions will lead
to failure.  At this point there is not a good repair on the market.  The
best in a non-stress bearing area consists of micro-blaster etching
followed by Parkell meta-bond, and then a composite resin bonded onto the
metabond.  If the area is stress bearing, in other words, on a biting
surface, the repair will probably fail.  If this is the case, and the area
is not cosmetically significant then have the dentist smooth the fractured
area and forget it. Or have the entire bridge replaced.  This problem
happens to all of us occaisionally and is very frustrating when it occurs.
 The introduction of porcelain to metal in the last few decades have
forced us to often give in to the demands of the cosmetic desires of
patients, when more traditional ( all metal) crown and bridge techniques
should be called on for from a strict materials viewpoint. Good Luck



Wed, 03 Feb 1999 03:00:00 GMT
 
 [ 5 post ] 

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