The Immediate Denture
The goal of dental treatment is to help people stay as healthy as they can. For most patients that means keeping the teeth and gums as healthy as possible. There are circumstances when it is no longer possible to maintain teeth and the decision must be made to remove the remaining teeth in one or both arches. Advanced tooth decay, untreatable gum disease, trauma and systemic diseases sometimes make it impossible to maintain natural teeth. When the decision to remove the remaining teeth in one or both arches has to be made, the teeth are replaced with a prosthesis more commonly know as a full denture. A full denture may be made to replace all upper teeth against some natural lower teeth or all lower teeth against some natural upper teeth or full dentures may be made for both upper and lower arches.
In the old days, people would have all of their teeth removed and a period of healing would be required before the dentures could be made. Two to three months healing time is optimum. While some people still prefer to make the transition from natural teeth to dentures in this fashion, most patients, for social reasons, would prefer to never go without their teeth. To accommodate these patients, a technique has been developed that allows placement of the full denture the same day that the remaining front teeth are removed. Dentures made in this fashion are called immediate dentures. However, immediate dentures are probably better described by the more appropriate term of transitional dentures. This term is more appropriate because the day that the last teeth are removed and the dentures placed is the beginning or transition from natural teeth to denture teeth.
The transitional denture has three or four phases. The first phase is preparatory extractions of all posterior teeth in the arch to receive the denture. All molars and bicuspids are removed and the bone and overlying gums are allowed to heal. Sometimes upper and lower first bicuspids are left to keep the bite dimension from changing as well as provide a broader smile during healing. The healing period varies but is usually six to eight weeks. Some patients will have transitional removable partial dentures made to replace the back teeth. These partial dentures are used only during the healing of the posterior areas phase. They can be placed the same day the back teeth are removed and will require some adjustments for fit and function during healing. Use of transitional removable partial dentures is not always possible so each case must be determined on an individual basis.
Once the gums over the posterior extraction sites have healed, the second phase is begun, namely, the process of fabricating the transitional denture. Preliminary and final impressions of the posterior ridges and front teeth are made. Wax rims to establish jaw-to-jaw relationships are used and finally a wax try-in of posterior teeth is done to verify the jaw-to-jaw relationship of the teeth as they are set up in wax. Here is the major difference in fabricating transitional dentures versus making a full denture for patients who have already lost all of their teeth. With patients who have already lost all of their teeth, it is possible to try in the denture with all of the teeth set in wax including the front teeth. This is important as the position of the front teeth within the denture is critical to the smile, phonetics and lip support. All of these positions can be verified when all of the teeth are gone in the wax try-in. With the transitional denture, the position of the front teeth can only be approximated. The importance of this is discussed below.
After the wax try-in of posterior teeth, the patient may return to the dental office to view the final arrangement of the teeth before the teeth are processed in acrylic. Some people may want personal customizations in the form of rotations, spaces or other imperfections built into the arrangement of the teeth to make them look more like the patient’s natural teeth did. Once approval of the final arrangement of the teeth is given by the patient, the teeth are processed for delivery.
On the day of delivery, the remaining teeth are removed and the denture(s) is seated. Any obvious bite discrepancies or over-extended edges are adjusted and the patient is dismissed with post-operative instructions. The patient is seen the next day to have the dentures removed and sore spots adjusted. It is almost a given there will be sore spots. Only severe bite discrepancies are adjusted at this time as irregularities may be caused by swelling that will settle in once the swelling subsides. Patients may be instructed to use adhesive and/or analgesic ointment at this appointment. This is the start of the third phase-healing of the front ridge.
For the next six to twelve weeks, many changes in the bone of the front ridge will cause settling of the denture. The patient may experience additional sore spots and the denture may become loose fitting. Adjustments to the acrylic base edges will alleviate sore spots. It will be necessary to do soft chair side relines of the denture base as healing occurs.
Once healing is completed, the decision must be reached by the patient and dentist whether or not the transitional denture meets the needs of the patient. If the bite, cosmetics (shade, shape, arrangement), lip support, phonetics and smile line reveal are acceptable, the denture is then rebased. The soft chair side reline material is replaced with permanent acrylic or sometimes permanent soft liners that are heat processed in the dental laboratory over night. Note it is necessary to keep the denture from the morning of one day to the afternoon of the next so the patient’s social affairs will have to be taken into consideration. The permanently rebased full denture is placed in the mouth and a few more appointments may be required for sore spot adjustment and bite refinement. If all goes well the patient is then dismissed and seen annually for observation.
Unfortunately, not all transitional dentures make the transition smoothly. When the front teeth are set in wax, it is a best guess as to where they will end up in the mouth. Some patients heal differently and others will decide that the cosmetics of the new teeth do not meet their needs. In this circumstance, instead of permanently rebasing the transitional denture after the front ridges have healed, a completely new denture is made, this time with the advantage of being able to have a wax try-in of all of the teeth as well as having the first denture to compare results. The process is the same: preliminary and final impressions, wax rims to establish jaw-to jaw relationships as well as position of front teeth incisal edges, wax try-in for verification and then delivery of the new denture. The fourth phase of re-making the denture all over again is not usually necessary, but must be taken into account as possible prior to initiation of treatment. If remaking the denture is required, the old transitional denture can be rebased anyway and used by the patient as an emergency ”spare” denture to be used if something happens to the new final denture. Note that even if the first denture proves to be satisfactory, an economical duplicate denture is recommended for emergencies and out-of-town travel.
A final word about transitional dentures. Full dentures require adequate bone to be held in place. Uppers are held in by suction, lowers by gravity and the muscles from the tongue. Retention of dentures in both arches becomes difficult as the patient ages due to the loss of bone in the ridges under the dentures. The change is striking in the first couple of years and can, over a period of many years, result in a ridge that is unable to retain a denture. Surgical replacement of bony support is difficult to accomplish. At this time, dental implants are no longer the wave of the future. Their time has arrived now. Implant-retained dentures are not supported by the bony ridge but rather by implant fixtures. Studies show that implants will also prevent the loss of bone that results in thin inadequate ridges. It is now considered the standard of care to receive implants to retain and preserve bone. While a full denture will never have the biting strength that natural teeth have, implant-supported full dentures with good bone support will provide the closest thing to having your natural teeth. With annual adjustments, implant supported dentures have the potential to last many years with greater comfort and better chewing function and at the same time preserve precious bony support.
Making the transition from natural teeth requires good communication and a lot of pre-operative information. With good communication between the patient and doctor, the transition from natural teeth to dentures can be made as easily as possible. If you have any questions about the process, please feel free to discuss them with Dr. McCarthy.