Distal cusp broke on back molar

Discussion in 'Dental Archive' started by Rich Wales, Aug 24, 2006.

  1. Rich Wales

    Rich Wales Guest

    Short version of my question: When repairing a backmost molar,
    is it REALLY essential to restore a broken distal cusp? If so,
    why?

    Longer story:

    A few months ago, the distal-lingual cusp on my mandibular left
    second molar (#18 in the US; #37 in Canada and elsewhere) broke
    off without any warning (and without any pain) while I was eating.
    FWIW, since my wisdom teeth were removed when I was in my teens,
    my second molars are my backmost teeth.

    My dentist has attempted to repair the tooth twice, by building
    a new cusp using composite resin. The first time, the new cusp
    seemed just fine at first, but it broke off after about a month
    (just like the original cusp). The second repair attempt also
    seemed OK initially, but it too broke off, this time after only
    about a week.

    Assuming a root canal is not needed (I'm seeing an endodontist
    next week to have the tooth evaluated for possible RCT), I'm
    wondering what my options might be for further restoration. I
    realize one (maybe the best, or even the only) approach is a
    crown -- but I want to know if anything else makes sense (again,
    assuming I end up not needing RCT, in which case I understand
    there would definitely be no alternative to a crown).

    In particular, I want to understand if it might make any sense
    to put another filling over the broken area of the molar, but
    WITHOUT attempting to construct a full-fledged cusp where the
    original cusp had been. (Sort of like a permanent version of
    the temporary "sedative" filling which was put on the tooth
    right after the original breakage, before my regular dentist
    could do his first repair attempt.) I realize the result of
    this sort of permanent repair would, at the least, involve a
    slight reduction in chewing function -- owing to the one missing
    cusp -- but I'm not sure I understand how much of an issue this
    is. Is there some specific anatomical reason why this kind of
    repair wouldn't work? Or is this just something so completely
    out of the question that a reputable dentist would simply never
    even consider it?

    Rich Wales http://www.richw.org
    *DISCLAIMER: I am not a doctor. My comments are for discussion pur-
    poses only and are not intended to be relied upon as medical advice.
     
    Rich Wales, Aug 24, 2006
    #1
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  2. Rich Wales

    C.J. Thomas Guest

    Unless you are having symptoms on the tooth, the endodontist should not
    recommend a root canal. Endodontists can perform root canals on
    anything...however, if the tooth is asymptomatic, and the referring dentist
    isn't even sure if he/she is going to put a crown on it, what more can the
    endodontist really tell you?


    "Rich Wales" <> wrote in message
    news:...
     
    C.J. Thomas, Aug 24, 2006
    #2
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  3. Rich Wales

    Rich Wales Guest

    "C.J. Thomas" wrote:
    The reason I was referred to the endodontist is that I've started
    having intermittent pain in my lower jaw near the tooth in question
    (#18) -- especially if I've been chewing or if I eat something cold
    (I don't drink coffee or tea, so I'm not sure about heat sensitivity).
    I'm taking ibuprofen (Advil / Motrin) for the time being to manage the
    pain, plus topical Orajel (benzocaine) as needed.

    I'm not afraid of having a root canal if necessary, but I don't
    intend to agree to RCT unless it really is necessary (i.e., unless
    there really is pulp infection). The referral to the endodontist is
    to determine if RCT is really required in my case or not.

    My primary dentist actually recommended a gold crown at the start,
    but when I hesitated to have such an invasive and expensive procedure
    done right away, he opted for a more conservative route (which,
    however, appears not to be feasible after all). I understand that
    if I do have a root canal, this will definitely make the tooth weaker,
    and I'll really have no option at that point but to have a full crown.

    I had a large (mesial-occlusal-lingual) amalgam filling put on #18
    when I was in high school. This amalgam lasted over 20 years until
    it started to break down and was replaced with another amalgam about
    a dozen years ago. My current dentist recently replaced this large
    amalgam again, a couple of months ago, with a composite resin filling
    because it was starting to break down again. It's been suggested to
    me that one reason #18's distal-lingual cusp broke off recently may
    be because replacement of such a large amount of the tooth with a
    filling, decades ago, has subjected the tooth to extra stresses over
    time (which were bound to cause further problems eventually).

    Rich Wales http://www.richw.org
    *DISCLAIMER: I am not a doctor. My comments are for discussion pur-
    poses only and are not intended to be relied upon as medical advice.
     
    Rich Wales, Aug 24, 2006
    #3
  4. Rich Wales

    Rich Wales Guest

    Steven Bornfeld wrote:
    OK. Thanks for mentioning this. How would an onlay typically
    compare, in terms of cost, with a full crown? (I want to be
    cost-conscious if possible, and I'm sure my insurance will also
    be interested in the cost issues. :-})
    Hmmm. So, omitting the broken cusp in a restoration of #18 might
    not really reduce the stresses, then, as I had imagined it would?
    And something I didn't mention in my initial posting is that I had
    a sizable amalgam (covering most of the mesial-occlusal-lingual
    quadrant) put on #18 when I was in high school. This amalgam
    lasted over 20 years until it started to have problems and was
    replaced with another amalgam about a dozen years ago; the second
    amalgam, in turn, started breaking down recently, and my current
    dentist replaced it with resin a couple of months ago.

    It's been suggested to me that having such a sizable restoration
    on this molar, so long ago, means the molar has been subjected to
    significant additional stresses for decades, and that eventual
    breakage of the distal-lingual cusp was probably inevitable sooner
    or later.

    I haven't really had a lot of cavities since high school, though;
    I've brushed and flossed regularly for many years now.

    Rich Wales http://www.richw.org
    *DISCLAIMER: I am not a doctor. My comments are for discussion pur-
    poses only and are not intended to be relied upon as medical advice.
     
    Rich Wales, Aug 24, 2006
    #4
  5. Rich Wales wrote:

    Generally the fees should be pretty close.

    Including a cusp will definitely increase the chances of the
    restoration breaking IF the cusp is in function. Often the lingual
    cusps of lower second molars aren't in heavy function. This depends on
    the particular way your teeth come together.

    Certainly having a large restoration weakens the remaining tooth
    structure. If the restoration is wide it particularly predisposes the
    cusps to fracture (this has to do with the anatomy of the enamel and
    direction of the enamel rods). Amalgam also expands slightly when
    setting. Some people maintain that this leads to fracture, and would
    favor composite resin for this reason. However, composite resins
    contract when setting (and by a considerably higher magnitude than the
    expansion of amalgam) so I don't think resin would be any less likely to
    encourage fracture.
    In any case, if the restoration is wide, the cusps should be
    covered--whether by an onlay or a crown. It really doesn't matter in
    this context whether you have a full contoured cusp in function or not.


    Steve

    --
    Mark & Steven Bornfeld DDS
    http://www.dentaltwins.com
    Brooklyn, NY
    718-258-5001
     
    Mark & Steven Bornfeld, Aug 24, 2006
    #5
  6. Rich Wales

    Rich Wales Guest

    Steven Bornfeld wrote:
    My mandibular second molars are slightly lingual in relation to
    their maxillary counterparts. The lingual cusps of my maxillary
    second molars are lined up with the occlusal basins of the
    corresponding mandibular second molars.

    When I close my jaw slowly and carefully, the first points of
    contact between upper and lower teeth involve the second premolars
    (#4 touching #29, and #13 touching #20).

    Rich Wales http://www.richw.org
    *DISCLAIMER: I am not a doctor. My comments are for discussion pur-
    poses only and are not intended to be relied upon as medical advice.
     
    Rich Wales, Aug 25, 2006
    #6
  7. Rich Wales

    Rich Wales Guest

    Steven Bornfeld wrote:
    Thanks. I'll ask about that after the current problem with my #18
    has been taken care of.

    Given what I've described, though, does it sound like it would be
    that crucial to restore a fully functional distal-lingual cusp on
    my #18? (Assuming, of course, that I don't end up needing a root
    canal and a full crown.)

    Rich Wales http://www.richw.org
    *DISCLAIMER: I am not a doctor. My comments are for discussion pur-
    poses only and are not intended to be relied upon as medical advice.
     
    Rich Wales, Aug 25, 2006
    #7
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