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coronal blood staining on the crown - Courtesy ROOTS
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The opinions and photographs within this web page are not ours. Authors have been credited for the individual posts where they are. - www.rxroots.com |
From: Terry Pannkuk To: ROOTS Sent: Friday, May 22, 2009 9:27 AM Subject: RE: [roots] Again: retreatment, surgery or implant? I always seem to be completing a case that fits whatever topic we are discussing. It's extremely rare that I do endo surgery. This is the sixth case I treated with this technique. So far the the amalgam has been removed uneventfully in each case I've chosen. This is the only one where I left some amalgam specs in the tissue. It would have been nice to get everything out pristinely, but I doubt the remaining specs are large enough to result in an amalgam tattoo. The patient was very happy and had no discomfort after the first visit. These cases get a bit bloody when you lavage and clean the apical region of debris (you can see the coronal blood staining on the crown on my first visit photo after completely cleaning and shaping the large irregular apex. I also took some demo shots to show how I've figured out to ideally bevel the fiber post to maximally retain the coronal core. I've seen many cases where those performing buildups indiscriminantly and inaccurately cut back the post to the point that it is likely providing no coronal retention and balance of stress forces. It only takes a few moments to measure the post depth of the "gingival height" and "coronal height" to the respective lingual and labial access cavosurface margins. In this case the linguoginigval measured 12mm to the base of MTA and the labiocoronal measured 15mm. Grabbing the fiberpost with a set of college pliers at 11mm, I was able to very accurately create an idealized bevel leaving just 1mm of depth that would clearly be out of occlusin but allow coverage with the Filtek composite so that the post woudln't be exposed. There was no need to complicate the bonding by adding a weak opaque layer, so the composite clearly doesnt' disappear on the surface. I was mostly concerned about idealizing retention and strength, not worrying that the shallow layer of surface composite would be translucent to the dark post - Terry
Great case Terry. I would have done the same. However, I have one question. Why did you have to place post, specially since there was no post previously, and my concern is now the occlusal forces can be transferded to the root, increaing the risk of root fracture specially if there isn't a good ferrel all the way around. How about just placing composite in the root over the MTA to strenghten the root if this i a concern. just brain storming here!!!!! - Mohamed Good question. the lit is equivocal so I error on the side of placing it to satisfy the referral who expects it for the presumed balance of stress forces along the root and crown. Fiberposts have a matched modulus of elasticity to root dentin; metal posts do not. The predominant educated opinion seems to be to place fiberposts for this reason. If the referral expects it, I pop one in. :):):) - Terry Are there any documented cases of fibre post induced fracture? I thought the incidence was extremely low and failure is by lacl of retention rather than fracture? - Bill if there is no good ferrel all the way around the crown prep, I think any post can increase the risk of root fracture - Mohamed Let’s get marga’s opinion. She uses a lot of them. I personally have not had a single one fracture. With a 2mm ferrule. - gary I am currently writing a piece on posts, so here is some backgound info: There is a huge difference between rigid and non-rigid posts. Metal posts are have a high modulus of elasticity, which means that they are stiff. Therefore they are able to withstand forces without distortion. However, the force must go somewhere. Force from a stiff post is transmitted to the less rigid root dentin, next to the apex of the post. Stress concentration in the post/root complex can lead to cracking and fracturing. To overcome the concerns about unfavorable stress distribution generated by metal posts, fiber-reinforced composite resin posts were introduced in 1990, with the aim of providing more elastic support to the core. The reduced stress transfer to tooth structure was claimed to reduce the likelihood of root fracture, as the modulus of elasticity of these fiber posts is closer to that of dentin than that of metal posts. Posts made of non-stiff materials (low modulus of elasticity) are more resilient, absorb more impact force, and transmit less force to the root than stiff posts. The clinical evidence supporting the use of fiber posts is abundant and largely superior to that supporting the use of metal posts. Fiber post-composite core restorations are effective in preventing the loss of root canal treated teeth as a consequence of root fracture - Marga
