Re: Fibre Posts


"Dr. Steve" <drsteve@xxxxxxxxxxx> wrote in message
news:o0l651hhj3ku9smt81tduj171m5poafnkv@xxxxxxxxxx
> On Tue, 5 Apr 2005 22:49:04 -0400, "NOYB" <NOYB@xxxxxxxx> wrote:
>
>>
>>"Dr. Steve" <drsteve@xxxxxxxxxxx> wrote in message
>>news:tji651tiv3319qiolr7cvfnpdfiisbh58s@xxxxxxxxxx
>>> On Tue, 05 Apr 2005 18:05:35 GMT, "Charlie Oster via MedKB.com"
>>> <forum@xxxxxxxxx> wrote:
>>>
>>>>The fundamentals of restoring endodontically treated teeth are something
>>>>we
>>>>all know: conservation of tooth structure, adequate post length (if you
>>>>use
>>>>a post) good post fit, anti-rotation, ferrule. Most important element,
>>>>from the viewpoint of longevity of the restoration, is ferrule.
>>>>
>>>>Which post material one uses is not very important, with the exception
>>>>that
>>>>there seems to be some evidence (there ain't much) showing that custom
>>>>(not
>>>>prefab) zirconia posts w/ceramic core might be a bad idea.
>>>
>>> Whoa!
>>>
>>> Dump the ferrule. It is responsible for most of the crowns which snap
>>> off at the gingival crest
>>
>>But it prevents root fractures when there's a post.
>>
>
> No, it accelerates the fracture.

Perhaps you're talking about something different. I'm talking about having
the crown margins extend beyond the buildup so that the margin encircles the
tooth and root. Saying that a ferrule accelerates root fracture is like
saying that a crown accelerates vertical fractures down the central fossa of
teeth. It's counterintuitive.

Simple physics (statics) can demonstrate why encirclement of the root is
beneficial. If that's not convincing to you, then I'd refer you to the
study done by Hoag and Dwyer:


J Prosthet Dent. 1982 Feb;47(2):177-81.


A comparative evaluation of three post and core techniques.

Hoag EP, Dwyer TG.

An in vitro study was performed evaluating three post and core techniques
with and without full crown coverage on extracted mandibular molar teeth.
The materials evaluated were amalgam, composite resin, and stainless steel
posts, and a combination of cast-gold and stainless steel posts. The results
indicate that the method of post and core technique may not be as
significant as the placement of full coverage cast-gold crown restorations
with sound design and placement of margins beyond the buildup restoration.


.