To place an implant, there must be an adequate amount of bone to bear the brunt of the bite. In the upper molar area, it is very common to be short of bone for implants since the maxillary sinus is located right above it. Since the bone shrinks once a tooth is removed, it is not unusual to find only a few millimeters of bone remaining. In these cases, a procedure called a sinus lift bone graft is available. In a sinus lift, a flap of gum is retracted from the upper jaw in the molar area, and a small window is cut into the bone being careful to not lacerate the sinus membrane. The sinus membrane is gently “lifted” and a bone graft material is placed in the hollowed out space in between the lower part of the sinus bone and the membrane. The surgical site is closed and allowed to heal undisturbed for a number of months. At this point, the bone will be fully organized and ready for implant placement. A sinus lift procedure has over 90% success rate. The feedback that I have gotten from patients as far as the recovery from the procedure has been very favorable. The technique opens up many more opportunities to restore the upper jaw with implants instead of having to resort to dentures.
For an implant to be successful, there must be adequate bone available for proper placement. Since the bone and gums will shrink away once a tooth is removed, it is not unusual to have a situation where there is an inadequate amount of bone to place an implant. Simple techniques start with socket preservation where the dentist places a bone grafting material in the socket at the time of tooth removal. Even more predictable is placing a membrane over the graft material. This will allow the graft to heal undisturbed and has a very high rate of success. Once the bone height has shrunk, then a block graft needs to be done to give the bone more vertical. A block graft uses a piece of cortical bone that is obtained from another part of the body. Common areas are the mandibular ramus (the part of the jaw bone that lies behind the lower back teeth) or the mental symphysis (part of the chin). Once a block of bone has been harvested, then a flap of gum is peeled back at the donor site and the block is held in place with screws. Since the procedure utilizes bone from the same person, it doesn’t reject the graft. After allowing the area to heal for a few months, then the site will be ready for implant placement.
There are a number of techniques available to build up the jaw bone to give a good base for dentures. With autogenous bone grafts, a piece of bone is harvested from another part of the patient’s body. The most common area to get the bone from is the iliac crest. This is the part of the pelvis that lies above the hip joint. The body tolerates the bone graft since it is from the same person, so there is no risk for rejection. However, the surgical procedure that is utilized to obtain the bone can be somewhat debilitating. The feedback that I have gotten from patients is that the hip was much more uncomfortable than the mouth. Another technique is an allograft. This procedure utilizes cadaver bone. The sterilizing and screening techniques make for a wide margin of safety for cadaver bone. And the great news is there is not a need for an additional painful surgical site and long recovery period. Although the surgical success rate is good with allografts, they are still not as predictable as autogenous grafts (utilizing the body’s own tissue). After a few months of healing time, a denture can be safely constructed that should provide years of service.
To place dentures, there must be an adequate amount of jaw bone available to provide a place for the dentures to seat. Soft tissue is not firm enough to give proper support for false teeth. Alveolar bone is the bone that holds the teeth in place. That is its only purpose, so once the teeth have been removed, the body figures it has no more use for it and it resorbs (dissolves away). If the teeth have been missing for too long, then the available bone to hold a denture on is virtually nonexistent. That’s where bone augmentation helps. It is a surgical procedure to add bone to selected areas of the mouth. This will increase the height of the bony ridge and will give the denture more stability. There are a number of techniques available to add height to the jaw bone. These are particulate and bone graft substitutes. There are fancier membrane techniques where a thin membrane covers the graft material and allows the graft to heal undisturbed. There are autogenous bone grafts where a piece of bone form one’s own body is used and there are allografts which utilize cadaver bone for its source. The ridges can also be widened utilizing distraction osteogenesis. I will discuss each technique in more detail in Part II.
Most tooth extractions heal uneventfully, however, recovery can be greatly complicated by the dreaded dry socket. A dry socket occurs when the blood clot that fills the socket becomes dislodged or never fully forms in the first place. It is important after a tooth extraction to leave the surgical site undisturbed so that the blood clot has a chance to mature. If one vigorously rinses their mouth out or puts negative pressure in their mouth by doing things like sucking through a straw or drawing in cigarette smoke, the blood clot can easily come out. The result is a hole in the gums – hence the term “dry socket”. Another big factor is smoking. The nicotine will constrict blood vessels making it difficult for a proper blood clot to form, Making one more susceptible to a dry socket.
When a dry socket does occur, you will know it. After three to four days following the extraction, an intense pain will occur. There will be no redness or swelling, like with an infection. You can try to control the pain with an anti-inflammatory, such as ibuprofen, but it is best to call your dentist. Although a dry socket is not life threatening, it still is extremely painful and your dentist can help relieve the pain. Plus, it would be good that the dentist can rule out more serious problems. If it is a dry socket, then the dentist will flush out the debris from the socket, then place a medicated packing in the area for one week to ten days. The dry socket should be healed by that time and the packing can be removed.
Removing a tooth is not the brute force that is the common perception. Extracting teeth actually requires a lot of finesse. There is a small space between the tooth and the bone. This is where the periodontal ligament resides. This ligament is what holds teeth in. Teeth are not set rigidly in concrete. If you’ve ever looked in the mirror and tried to wiggle your teeth with your fingernails, then you’ve probably noticed that the tooth will move slightly. This allows the force of the bite to be buffered before it gets transmitted to the bone. The trick to extracting a tooth is to break the periodontal ligament. Pressure is applied slowly until the microscopic fibrils of the ligament begin to snap. If the pressure is applied too fast, then the tooth will usually break apart in a very inopportune place.
The pressure to extract a tooth can be applied by a variety of instruments; the most common being the forceps. Forceps look like common household pliers only with very specialized beaks. Other instruments called elevators are commonly used. Elevators resemble a screwdriver, except that is is curved to match the contours of a tooth. An elevator is placed between the teeth and gently rotated until the tooth raises from it’s socket. This way, teeth can be removed in a very comfortable manner.
A goal of every dentist is to save teeth, however, there are times that the best thing for a tooth is to remove it. If there is not enough room for wisdom teeth – out they come. If the teeth are too crowded, then the orthodontist may recommend extracting some strategic teeth to make room. We can rebuild teeth that are broken down by decay or fracture from the “ground up” but if the damage slips too far below the gums or bone, then the best alternative may be extraction. Fractured teeth many times can be saved by placing a crown or cap over them, however, if the fracture goes too deep into the root, then the only solution is removal. Teeth that have had root canal treatment tend to be very brittle since there is no nerve inside to bathe the tooth with fluid. If these teeth are not restored with a crown, then there is a high likelihood that the tooth will split and need to be taken out. The most common reason for the need for tooth extraction is gum disease. Severe periodontitis (gum disease) can affect many or all teeth in the mouth causing the teeth to loosen and thus will need to eventually be removed.