A note on upper molar extractions
A little while ago I posted on detecting and managing curved roots in premolars.
http://dental-tidbits.blogspot.com/2019/06/premolar-extractions.html
I recently extracted an upper molar with fairly curved buccal roots. One thing I noticed was the xray exposure happened to obscure the curvature of these roots. One tip I would suggest is to spend adequate time inspecting your preoperative xrays before starting the extraction. This can be before the appointment if the procedure is planned or during waiting for local anaesthesia to settle in if it is not.
Play with the contrast and brightness and sharpness filters if your program has one. Thicker or thinner bone can obscure root features and thin roots can be burnt out by higher exposures. Slowly follow or trace the external boundaries of the root surface to describe the root shape and never underestimate the variability of posterior root forms.
The good thing about upper molar roots is that the form is usually quite defined on a radiograph as the roots do not tend to over lap each other unless you have taken a tube shifted xray (anteriorly or posteriorly) or from too high or low of an angle.
In these case, the tooth mobilised very quickly, expansion of the bony plates allowed quite free motion of the whole tooth but extraction was quite difficult. Anecdotally, I found that the tooth could be elevated quite freely buccal to lingual but had resistance to mesial or distal movement. This can be explained as the curvature of the MB root prevented movement mesially and DB root prevented distal movement away from their path of elevation but buccolingual movement was allowed by the expansion of the buccal plates.
Again, this is a matter of do as I say not as I do. My previous advice was that if the tooth mobilised quite easily but wouldn't come out to section the tooth or to risk root fracture at or below the furcation. In this case, the DB root fractured below the furcation and was removed with root tip elevators. In teeth with roots of opposing paths of elevation, the fracture of the weaker root will allow less resistance to elevation of the rest of the tooth.
http://dental-tidbits.blogspot.com/2019/06/premolar-extractions.html
I recently extracted an upper molar with fairly curved buccal roots. One thing I noticed was the xray exposure happened to obscure the curvature of these roots. One tip I would suggest is to spend adequate time inspecting your preoperative xrays before starting the extraction. This can be before the appointment if the procedure is planned or during waiting for local anaesthesia to settle in if it is not.
Play with the contrast and brightness and sharpness filters if your program has one. Thicker or thinner bone can obscure root features and thin roots can be burnt out by higher exposures. Slowly follow or trace the external boundaries of the root surface to describe the root shape and never underestimate the variability of posterior root forms.
The good thing about upper molar roots is that the form is usually quite defined on a radiograph as the roots do not tend to over lap each other unless you have taken a tube shifted xray (anteriorly or posteriorly) or from too high or low of an angle.
In these case, the tooth mobilised very quickly, expansion of the bony plates allowed quite free motion of the whole tooth but extraction was quite difficult. Anecdotally, I found that the tooth could be elevated quite freely buccal to lingual but had resistance to mesial or distal movement. This can be explained as the curvature of the MB root prevented movement mesially and DB root prevented distal movement away from their path of elevation but buccolingual movement was allowed by the expansion of the buccal plates.
Again, this is a matter of do as I say not as I do. My previous advice was that if the tooth mobilised quite easily but wouldn't come out to section the tooth or to risk root fracture at or below the furcation. In this case, the DB root fractured below the furcation and was removed with root tip elevators. In teeth with roots of opposing paths of elevation, the fracture of the weaker root will allow less resistance to elevation of the rest of the tooth.
Sometimes it is also helpful to rotate the tooth. You can use a lower tooth forceps for mechanical advantage. Resistance to M/D movement is also due to the adjacent teeth.
ReplyDeleteThank you very much for your comment. Yes, resistance to M/D movement is hampered by the adjacent teeth. In this case it was a lonestanding molar which is always a risk factor for increased difficulty.
DeleteLower molar forceps can absolutely be fantastic for upper tooth extractions. Lower universals are the "most universal" universal forcep. Having the handle offset at 90 degrees to the working end does allow a mechanical advantage at the cost of less surface area contact with the tooth. In this post, my learning moment was to recognise the severe curvature of the roots and more force isn't always the answer when having difficulty extracting teeth.
Do you find that rotating upper molars with fragile roots increases the rate of root tip fracture? I certainly find your tip useful in lower molars which have more robust root structure as well as anterior teeth which are more conical.
Rotation of upper molars hasn't caused root fractures for me. I think most of the force goes to the PDL.
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