Introduction To Dental Implants by Dr Chan Joon Yee For many people who have lost their teeth for one reason or another, wearing a denture may not be the best solution in terms of function, comfort, appearance and durability. If good supporting teeth are present, bridges may be considered. However, one obvious disadvantage for bridges is that the supporting teeth will need to be trimmed. If these teeth are perfectly healthy, then some patients may not find bridging an acceptable alternative. Patients often ask me if it's possible to replace the mising tooth without cutting and crowning the adjacent teeth. Very often, this question is asked not to preserve healthy tooth structure, but rather to lower the cost of doing a bridge. "Is it really necessary to have 3 teeth constructed when I'm only missing one tooth? Why can't you just make one crown in that space?". Well, the reason is obvious. First of all, you can't have an artificial crown hanging in the air and secondly, you can't have it sticking on soft, mobile gums and still function like a tooth. Nevertheless, these patients may be pleased to know that their request for restoring just one tooth can be met. Our new clinic at Orchard has the facilities to provide a "one-tooth" solution to bridging that gap. We're talking about dental implants. For the layman, the implant is basically a titanium screw that is surgically inserted into the jaw bone to form the root component of the missing tooth. After giving time for the bone to heal and integrate with the implant, the implant can then be made to act almost like a natural root. This part of the implanted tooth is usually called the fixture. So far, the tooth replacement process described occurs inside the bone and under the gums. Proceeding to the next stage, an above-gum segment called the abutment, is attached to the "root" or the fixture. Once the abutment is firmly locked in place by tightening a tiny screw that goes into the implant screw well, it is crowned just like any natural tooth. If successful, the result is a fixed prosthesis that functions very much like a natural tooth. Apart from this conventional system which has been around for decades, there is a revolutionary implant system that does away with the screw. Appearing on the market since 1985, the Bicon system comes with an abutment that is held in place not with screws but friction between the abutment post and the implant well. This system works well most of the time, but the system has its limitations where bone is thin. It is certainly not an ideal system for complicated cases like ridge split and sinus lift. Bicon is no longer our system of choice. The bad news for patients who are looking forward to spending less money with treatment on only one tooth is, implants are considerably more expensive that bridges. The reason doesn't lie in "new technology". Dental implantology has been around for about 70 years. The reason lies in the amount of time, planning and multi-disciplinary skills that go into sinking and restoring a successful implant. And let's not forget the investment that the clinic must make to purchase a reliable system. For more info on the history of implants, you may want to check this out. We can summarise some of the advantages of implants over bridges/dentures below. 1. There is no need to trim any healthy tooth structure next to the missing tooth. Existing crowns or bridges will not be affected. Also remember that the body cannot regenerate new tooth structure, but it can regenerate bone and soft tissue. Anything lost during surgery will grow back. 2. Bridges only replace missing tooth crowns with pontics. The missing root is not replaced. Well, so what? The root is not seen anyway. Not seen indeed, but hidden roots serve another function apart from supporting the crown of a tooth. Only bone with roots to support will retain their shape and form. Bone without any roots to support will be resorbed so that the precious calcium can be deposited elsewhere. Once a tooth is lost (along with its root), the bone around it will atrophy, resulting in cancave surfaces. An implant will not only restore the crown of the missing tooth, it restores the root and prevent bone atrophy. Denture wearers will find their dentures getting loose after a few years. Implants are far more permanent. 3. Bridges have their limitations in restoring toothless stretches with sunken bone. The teeth may be restored, but the sunken appearance in the gums will not be adequately restored with bridges. With surgical implants, natural or artificial bone can be grafted beneath the gums to restore the original youthful, unresorbed anatomy. In this respect, implants may be able to cover some of the limitations of bridges. 4. There is no need for any anchor teeth as the implant can serve as the anchor. Implant crowns are a far better alternative to cantilever bridges. Of course, crowns are not the only restorations you can build over implants. With the proper attachments, implants can also act as denture retainers. People who have always had problems with a wobbly lower full denture over a resorbed ridge may be relieved of years of misery after receiving just two implants with denture attachments. So you've decided to do implants Implants are really cool and complicated stuff that will make uncouth people who call dentists "tooth-pullers" swallow their own teeth. To start, we will need to take some fanciful xrays and study models so we can study the case and decide on whether it's a simple of complicated case. We are now a one-stop dental implant centre where you can have your implant surgery and restoration done. However, for the more complex cases or for cases with special needs, we will still need to refer you to an oral surgeon for the surgery. You'll have to give us a complete medical history and your attitude must be right. Implants invariably fail with poor oral hygiene. Individuals who lost their teeth because of neglect must be thoroughly "converted" before they are considered suitable candidates for implants. Another reality of implantology is post-operative pain. If you've had wisdom tooth surgery done before and you find the pain bearable, then the pain from implants shouldn't bother you too much. In fact, many patients tell us that it's surprisingly less painful than they expected. Remember there are far more painful cosmetic surgeries around. If you are very nervous and do not wish to know what is happening during the surgery, you may opt for intravenous sedation. Some dental surgeries are equipped to perform sedation. You can find out more about IV sedation here. After all preliminary examinations, we will decide on whether you are a suitable candidate for implants. This is not a driving test, so most people will pass. One common problem we encounter, however, is the lack of bone. You can see from the diagrams that the implant needs to be placed in solid bone. When this bone support is insufficient either in depth or in width, the implant will not hold. However, there is a solution to this problem. We do a bone graft. In other words, we add bone into the area where the implant is to be placed. There are many types of graft materials that can be used. Most popular are bone chips of bovine origin. They can be mixed with your own bone and grafted into the defect or bone deficient area. Certain synthetic bone particles (tricalcium phosphate) can also be used. Alternatively, human bone (from a deceased donor) can be used. It's more expensive and gives some people the creeps, but healing takes only 3 months compared to other non-human grafts which can take 6 months or more. Remember that bovine and human bone graft material will eventually be completely replaced by your own bone cells. Synthetic material will remain embedded in your new bone for life. Once the graft has settled in, we can treat it like your own bone and sink the implant as per standard procedure. Soft Tissue Graft When a bone graft is placed, the surrounding soft tissues, not used to the new bulk of bone, may not close completely. Imagine you have an envelope and you keep stuffing things inside. There will come a point when you can't glue the flaps together. It's the same with grafting bone particles into a sunken part of the dental ridge after opening up a flap in the gums. The more material is packed into the depression, the more dificult it is to replace the gums. To solve this problem, the surgeon can first try a split thickness flap. By slicing the gums thinner, they become more flexible and may be stretched over the new bulk. If that is still insufficient to close the gums properly, there are 2 other choices. One is to harvest extra gum tissue from another part of your mouth (usually the roof of your mouth). The obvious advantage is that the graft material is free. The obvious disadvantage is that it's going to be painful in 2 places. The other choice is to graft a material called Alloderm over the edges of your gums that are separated. The advantage is that there is no additional surgery on another part of your mouth. The disadvantage is that Alloderm is derived from human skin and is very expensive. However, rest assured that Alloderm is completely devoid of cells from the human donor and gets replaced by your own cells in a matter of months. Sinking The Implant We will arrange for a convenient date to perform the surgery. Described here are just some standard dental implant surgical procedures. Your dentist may employ a different style or technique because different cases may have different requirements. Procedures may also vary with the type of implant system being used. Stage 1 A small portion of the gum around the area of operation is raised from the underlying bone. The implants are then screwed into the holes which are gradually enlarged by a series of drills (or reamers in the case of Bicon). Once the implants are in place, the gums are stitched back over the implanted fixtures. With the implants safely buried under the gums, a temporary denture can be worn over the area. Stage 2 About 3 months later, the titanium in the implants would have integrated with the surrounding bone, This is when the buried implant is exposed. The dentist does this by cutting into the gum and removing the portion covering the implant. Once the implant is exposed, the dentist can attach a healing cap to it. This will prevent the gums from growing back to cover up the implant. Crowning A few weeks later, when the gums surrounding the healing cap has healed, the dentist will take an impression of the area to be restored. A few more weeks later, the crowns will be ready. The dentist will first tighten an abutment into the screw well of the implant. The crown is then cemented over the abutment. The restoration is complete. For Bicon implants, the technique is completely different. There are no screws at all. The abutment has a tapered post that is knocked into the implant well. The abutment is held in place not by a screw but cold weld between the abutment post and the implant well. One-stage Surgery The main reason for doing the surgery in 2 stages is to make sure that the newly placed implants can osseointegrate undisturbed. If a temporary crown is placed over an implant before it has integrated, osseintegration may fail due to forces directed on the "immature" implant. It is safer to stitch over the implant and keep it covered. However, for teeth which do not require temporary crowns (like back teeth), temporary healing abutments can be inserted over the newly placed implants. The gum is trimmed around the healing abutment and the latter prevents the gums from growing back over the sunken implant. With the healing abutment in place, there is no need to expose the implant at a second surgery. I would definitely indicate 1-stage surgery for most uncomplicated posterior implants. No More A Sunset Industry I used to see dentistry as a sunset industry but all that changed when I first handled implants several years ago. From that moment, I realised what an exiciting industry the field of dental implants really is. There is something new to learn every day. There are major developments almost every year. I now attend courses on dental implantology and cosmetic dentistry every month to update myself and to upgrade my skills. I have done implants for my own mother. Different Brands We are currently using 3 implant systems. They are Osstem, MegaGen and Nobel Biocare. We have our own Bicon® and Nobel Replace® Select Straight surgical kits. We do not need to rent any heavily used kit for our procedures with these 2 systems. Please call 62358316 for appointments or email us if you have any questions.