Crown Keeps Falling Off?

Clark, a dental implant patientm asks:
I have a dental implant with an abutment post for my crown. I’ve been back to my dentist 5 times because the crown keeps coming loose and I am worried about it falling off. Is there a stronger type of dental cement he can use to keep the crown on? Why does the crown keep coming loose? After reading many posts on OsseoNews I have to wonder if the abutment post has been adequately designed to hold the crown? Could this be the problem?

8 thoughts on “Crown Keeps Falling Off?

  1. The most likely situation is a mix of the following, A poorly designed abutment, a poorly executed crown and an inadecuate occlusion(THE WAY YOU BITE ON THE CROWN). So the most likely solution is to get a new abutment, crown and dentist. By the way yes there are very strong cements that will hold pretty much everything in place, even that crown, but if the occlusion is the problem, next time the crown comes off it will come off with the implant attached to it, overload would be inevitable and that is lethal to the integration of the implant.
    best of luck

  2. could u please elaborate why u asked about the implant system ?
    has the system to do any thing with the crown coming out too often ?

  3. Have there been problems with the Bicon system?
    My general dentist recommended that I find an oral surgeon who uses that system. He prefers it over a system that uses screws for a single tooth implant.

  4. You can have the abutments come loose in the anterior region. This is if used singly and with an implant less than 4mm. in width. This info applies to the Bicon System. I have found the MIS System to be very used friendly. Don’t get me wrong, I like the Bicon System. Everyone has their preference for whatever reason.

  5. To R. Hughes

    The tooth I am refering to is the second pre-molar. Is the implant itself supposed to be at least 4mm in width or were you referring to width of bone?

  6. Most implant systems use a screw to secure the abutment to the implant well. Bicon is a unique screwless system that relies on a phenomenon called cold welding. Consider it a kind of “friction lock” between the abutment post and the implant well.

    Cold welding works very well in most cases. Meticulously tapped in, it will take extraction forceps to remove the abutment. However, perfect cold welding is not always easy to achieve. Placed subcrestally, most implant wells are under 3-4mm of gingiva which may bleed. Blood, gingival fluid, saliva or even glove powder can contaminate the well and jeopardise cold welding. Keeping the implant well clean and dry to ensure proper cold welding is challenging in many cases.

    In the upper anterior region, there is an additional element of protrusive interference. Most patients will feel “shy” about going through the full extent of his/her protrusive movement when a new crown is issued. The dentist may not get any articulating marks on the crown and leave it alone.

    Another problem is the mobility of adjacent teeth. The lab technician works on rigid articulating stone models. In the mouth, adjacent teeth can move and transfer occlusal forces to the implant crown.

    It is quite common to see upper anterior Bicon crowns falling off.

  7. Linda,

    3.5-4mm Bicon implants have 2mm wells. 4.5-6mm Bicon implants have 3mm wells. As Bicon is a platform switching system, abutments of any width can come with 2mm or 3mm wells.

    As the 3mm well implants obviously offer more surface area for cold welding, any dentist would want to push for 4.5mm implant diameter at least. As long as you sufficient bone to accomodate a 4.5x8mm implant and the surgery is done in 2 stages, your dentist should have no problems restoring it.

    Perfect cold welding is not so crucial for back teeth.

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