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.
Whenever a tooth is lost, there is a mandatory healing period. Most people don’t want to walk around snaggle-toothed until a month or two has passed. There are some temporary measures that can be done in the interim to avoid the embarrassment of going without a front tooth.
If a bridge is planned, then the teeth on either side of the extraction site can be prepared (removing the enamel) and a plastic temporary can be constructed. This way, the patient can leave the office with their smile intact. One to two months waiting time is necessary before taking final impressions because the gums will recede during that time. If the permanent bridge is started too early, then there will be a hole between the artificial tooth and the gum will appear.
Another option is a temporary partial denture called a flipper. This nickname is very descriptive because the denture tends to flip around in the mouth during function. It has a plastic plate that covers the roof of the mouth, so it will affect taste and speech. But at least one can leave the office with teeth to smile with.
Single tooth implants can be brushed and flossed just like normal teeth. When two or more implants are tied together, special implements will be needed for daily cleaning. Bridge threaders are plastic needles that floss is threaded through the eye of the needle. The threader is passed under the bridgework, then the floss can be manipulated normally after that. Tiny brushes that look like baby bottle brushes are attached to handles and are a great way to get between teeth in areas that are accessible. A water pik can be used to clean food particles out from underneath a denture or bridge. It is important to use it on a low setting in order not to cause any damage to the gums that surround the implants. A water pik is not strong enough to clean plaque so a brush and floss is still mandatory. When a professional cleaning is done, it is important to let the dental hygienist know that you have dental implants. Special titanium cleaning instruments are necessary. Use of dissimilar metals can cause corrosion of the titanium implant surface. With proper home care, implants can last for many years.
Once an implant has had time to heal and an abutment (the metal post that protrudes through the gums) has been placed, it is now time to make the implant look and function like a tooth. Depending on how many teeth need to be replaced and how many implants are present will determine how the area will be restored. For a single tooth, it’s just a matter of constructing a conventional crown (cap). For a section of missing teeth, a row of teeth can be made and screwed into the abutments. For patients who are needing all of their teeth in a particular arch (upper or lower) replaced, there are a number of options available. If two implants are placed, then the abutments can be placed that have little balls that look like trailer hitches. Then “O” rings are placed inside the denture to allow it to snap onto the implant abutments. Although this setup doesn’t hold the denture in rigidly, it does keep it from shifting laterally, greatly improving function. If four or more abutments are present, then special clips can be placed in the denture that can hold the denture in fairly firmly. The denture can then be unclipped to allow for easy cleaning underneath. The other alternative is to screw the denture directly to the abutments. This way, the denture is rigidly held in place and is as close to having one’s natural teeth.
Once an implant has healed for a few months it is ready to restore. The implant has healed undisturbed for a number of months under the gums. At this point, the implant must be uncovered. It’s a simple procedure that can be done under a local anesthetic and results in only minimal gum soreness that can be eased with an anti-inflammatory such as ibuprofen. A healing cap is placed over the exposed implant so that the gums can heal around the area. Now it’s time to choose an abutment. An abutment is a post that attaches to the implant and protrudes through the gums. This provides a platform for a crown (cap) to be attached to the implant. If the implant was able to be placed in the bone relatively straight compared to the adjacent teeth, then a standard abutment can be placed on the same day. Otherwise, an impression (mold) of the mouth must be taken and a custom abutment would need to be constructed at a lab. The abutment is placed by tightening a screw to a specified torque. The implant is now ready to restore into a new tooth.
Dental implants need a minimum amount of bone to be sturdy enough to handle the stresses of biting and chewing. For those patients who lack adequate bone in areas where they have lost teeth, not all hope is lost. We now have very successful bone grafting techniques that can add enough bone to allow placement of an implant. In the back of the upper arch lies the maxillary sinus. It is not unusual to be short of bone in this area. A technique is now available where a small window of bone is removed and the membrane that lines the sinus cavity is raised up and bone graft material is placed in the resulting space. After a few months, new bone will grow in replacing the graft material. Then, the area is good to go for placing an implant. On a front teeth, when a tooth is removed, the bone tends to sink in when it heals. This makes it difficult at best to get a good cosmetic result around the gum line. By cutting out a block of cortical bone (the smooth hard bone on the outside of the jaw) from far back in the jaw bone and placing it over the defect, the sunken area can be corrected within a few months and will be ready to place the implant.
Once the gum tissue has been reflected away from the bone, the surgeon can drill on the bone all day without any discomfort, only vibration because there are no nerve endings in the bone. To place an implant, there must be adequate bone to hold the titanium cylinder. Now 3D x-rays are available to accurately measure the amount of bone and to avoid major structures such as nerves and sinuses. An incision is made in the gums, then the gums are pulled back to give the surgeon full visibility of bone. A hole is drilled into the bone and then the titanium implant is screwed right into the bone. The gums are sutured back into place and the implant is left under the gums undisturbed for a number of months. This allows the bone to grow directly around the implant, a process called osseointegration. Finally, once the implant site has fully healed, the implant can be uncovered and restored to a new tooth.