Dental Library- Dentures

Full dentures are used to restore a patient's arch or mouth, both upper and lower arches, when no teeth remain. Dentures replace the missing teeth allowing the patient to chew food, restore the esthetics, support the facial soft tissues, lips and cheeks, and reestablish the vertical dimension of your bite (the distance between your chin and nose). Dentures also aid in speaking, swallowing and smiling. But for all dentures do they are still the worst restoration dentistry has to offer and are therefore the restoration of last resort.

The shortcomings of dentures are many and varied. Dentures are removable and therefore can be lost or broken when out of the mouth. Dentures have nothing to attach to therefore they lie passively on the gums and subsequently have little to no retention. This makes dentures a potential source of social embarrassment if they happen to come out while eating, speaking or laughing in public. This is especially true of lower dentures since the amount of gum tissue they cover is far less than the surface area of gum tissue upper dentures cover. This allows upper dentures to be slightly more stable and more retentive than lower dentures. Denture adhesives can add some retention in the short run, but as we will see, over time the fact that all the teeth are missing will cause even the best-made dentures to become ill fitting and have very little retention.

Even the best made dentures become ill fitting over time because in the absence of any teeth the body continually resorbs the jawbone making it smaller, weaker and more susceptible to fractures. Dentures made even just a few years ago were made to fit a larger jaw that no longer exists, so the dentures can't possibly fit as well today as they did when they were first made.To minimize these adverse effects of bone resorption there are several treatments that can be employed. The first is to try to save any existing teeth or root tips that can be used as anchors to attach an over denture to. Having root canals done allow the remaining teeth or root tips to be saved and used for the anchor part of attachments for an over denture. This gives the denture something to attach to and consequently increases the dentures retention ten fold or more depending on the number of teeth and the type of attachments used. The presence of the teeth or root tips also helps to preserve the level of jawbone, which also improves the fit of the denture while decreasing the possibility of sustaining a jaw fracture.

Implants can be used as anchors for the dentures when there are no teeth or root tips. Just as with natural teeth and root tips the implants have the multiple functions of improving the retention and fit of the dentures while preserving the jaw bone of the patient. There are three levels of dentures attached to implants with each level the amount of retention, the number of implants needed, the type of attachments used, the complexity of the treatment and its associated costs increase.

The most fundamental denture attached to implants utilizes both 2 to 4 implants and the patients gum tissue to retain the denture. These restorations are called implants and tissue retained over dentures and usually employ attachments that are magnets or ball and sockets. The second level denture is totally implant retained and utilizes the patient gum tissue only for support. These are called implant retained tissue supported over dentures and usually employ 4 implants and an anterior fixed bar that is connected to the implants and which the over denture clasps onto. The third and best level of over dentures is completely implant retained and implanted supported thereby eliminating any need to use the patient's gum tissue for either support or retention. These over dentures typically employ 6 to 8 implants that are connected by a fixed bar that is nearly the entire length of the denture and to which the denture attaches to. These fixed bars can be either a round bar or for the best of the best a milled bar or spark erosion bar. These last two dentures give the greatest retention, stability and bone preservation.

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