Implants & Teeth Replacement
1. Dental Implant Surgery
Teeth serve an important role in our daily lives as it affects our speech, our ability to eat well and the way we look. Its loss through disease or trauma sets in motion the loss of underlying bony support resulting in tooth loss. This in turn affects support for our lips and cheek leading to a more aged appearance. Failure to replace missing teeth often leads to the opposing teeth overgrowing and the adjacent teeth tilting resulting in areas of food trapping which in turn may result in gum disease tooth decay.
Facial Symmetry, Proportion and the Golden Ratio
Traditionally, missing teeth were replaced by either removable plastic or metal based dentures, or fixed bridges made of either metal alone, or porcelain fused to a metal base. Developments in dental material science have focused on developing more aesthetic materials with adequate strength, such as all-porcelain and zirconia bridges. While all of these are still very much in use today, implant based methods of replacing missing teeth are increasingly preferred as it provides greater biting ability and a more comfortable and natural feel.
What are dental implants?
Dental implants are sterile titanium screws which are inserted into the jawbone as artificial roots to support and retain replacement teeth. It comprises 3 parts. The first part or “fixture” is placed within the jaw bone to replace the roots of missing teeth. The second part or “abutment” emerges through the gums and is used to carry the 3rd part, which may be a single crown or a bridge depending on how many teeth are missing. If we have lost all our teeth, we can use 4 to 8 implants in each jaw which when connected can support dentures or even a fixed bridge
How do Implants compare with alternative options?
When compared with removable dentures, they provide stronger support, firmer retention and are more stable. The implant supported and retained replacement teeth occupy less space and are more comfortable. They are also able to generate much stronger biting force. When compared with fixed bridges, they can be used even when more teeth are missing as they can provide stronger support over a longer span. They are also preferred when the teeth adjacent to the gap are weak or too small to provide sufficient support. Additionally, they provide an alternative to trimming healthy teeth.
Benefits of Dental Implant
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Are permanent replacement for missing teeth
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Has predictable and good long-term success rate
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Prevents supporting bone from shrinking after tooth loss
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Does not decay as it is made from Titanium
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Able to generate stronger bite forces for better chewing and hence better digestion and nutrition.
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Restores appearance thus creating more confidence and self-esteem Able to provide better support for lips and cheeks for a more youthful look
Types of Dental Implant
Dental Implants have been widely used for more than 40 years since the original scientific research was published. While many different implant systems are now available and are generally of high quality, our clinic prefers using implants from Nobelbiocare, Sweden and Straumann, Switzerland due to the extensive research and long track record. These implants come in different sizes and lengths and are generally at least 3.5 mm in diameter and 8 mm in length which differentiates them from “mini-implants” which should be used only as temporary supports or in very specific cases.
Are you suitable for Implants
Implants can be placed in most patients from age 18-80, even if you have lost your teeth for many years as we are able to regenerate bone in order to place implants as a foundation for your denture or bridge. Patients with health conditions should inform the dentist so that additional precautions can be taken, if required. Conditions which require attention include patients with significant heart disease, unstable high blood pressure, uncontrolled diabetes and patients on therapy for cancer. Surgery can still be performed after clearance from your medical specialist.
What is the surgical procedure like?
After giving some local anaesthetic, a small incision is made through the gums and a point of insertion decided. Drills of a predetermined length and with increasing diameters are then used to gently prepare the site to receive the implant. The implant is then rotated to the desired depth. The top of the implant channel is then covered with a temporary cap and the gums stitched either over or across after cleaning the surgical site and allowed to heal undisturbed for 3-4 months. A higher temporary cap called a healing abutment is often placed to avoid a second surgery to uncover the implant.
Is Implant Surgery Painful?
No, implant surgery is generally a minimally invasive procedure and in most instances the pain is minimal. If more major treatment is required, some post-surgical pain may be present. If you are fearful, we can arrange for you to have a complete pain-free experience either by performing the procedure under intravenous sedation or general anaesthesia within an operating theatre. The mix of drugs given will help you relax, sleep and eliminate pain. You will also usually be given a painkiller to take before the procedure so that you will be comfortable after the surgery.
How long does it take to recover from the Surgery?
After the operation, you may feel uncomfortable but this can be eliminated by taking the prescribed painkillers regularly. Some swelling and bruising is to be expected for a few days after the surgery. You can resume normal activity within a day but should avoid strenuous exercise and swimming. A normal or soft diet is advised and can be commenced after the numbness from the local anaesthesia wears off, usually around 2-3 hours after the procedure to avoid biting your lip or tongue inadvertently.
2. Implant Prosthodontics
What do we mean by Implant Prosthodontics
Implant dentistry is a 2-step procedure in which the implant is placed at surgery and the replacement tooth connected after bone healing 4-6 months later. The term prosthodontics refers to tooth replacement and can be either a single crown connected directly to the implant, an “implant bridge” to replace 2 or more missing teeth or even an “implant denture” to replace the full set of teeth when mounted on 4 or more implants. The term “implant overdenture” is used when the replacement denture is supported mainly by gums and underlying bone rather than by the implants placed.
How long do I have to wait before getting my permanent teeth?
After the implant is surgically placed in the jawbone and allowed to heal, it usually takes 3 to 4 months for the bone to strengthen around the implant and anchor it firmly. The implant is then uncovered to make a mould for the final restoration. Where possible, this second surgery can be avoided by placing an attachment which passes through the gums at the point of surgery. In some patients the bone is much firmer and it may be possible to load the implants earlier. Conversely patients with porous bone at surgery may require a longer period for the bone to heal.
What is the procedure like?
After the implant has completely healed, a mould is made of the implant by attaching a pin to the top of the implant. This allows the exact position and angulation of the implant to be recorded and transferred to the laboratory for scanning and processing of the final tooth. The relationship between upper and lower teeth is also captured. The final crown is then attached to the implant either directly using a special screw or it can either be cemented on the post which is screwed into position. The replacement teeth are made of porcelain on a base of metal, completely of porcelain or with zirconia.
Will the crown or bridge which is connected to the implant get loose?
No, it rarely happens as the final crown or bridge is usually attached firmly by using a special device to tighten the connecting screw or by utilising a strong cement. If it does dislodge, keep the crown and bring it along with you to the clinic. The dentist will clean the crown and cement it back if possible. If it happens again, there is a need to review the design to check if the forces in the implant are excessive or if the post which joins it needs to be changed. An X-ray is advised to check if the problem has caused any problem to the underlying implant fixture within bone.
How many implants are needed if we have lost all our teeth?
While some patients may choose to replace every missing tooth individually, dental implants are made from titanium, a very strong and lightweight material and 4 to 8 implants in each jaw may be sufficient to carry the load of the removable denture or fixed bridge, even when all your teeth have been lost. Your improved appearance and the ability to once again chew your food well will help you regain confidence and resume an active social life. Even if teeth have been lost for many years, it is still usually possible to rebuild the jawbone to place implants.
Is the final implant bridge or denture comfortable and can we chew better
Yes, the implant bridge or implant denture is more comfortable than wearing a conventional full set of dentures as implants allow better support and thus only a smaller denture base is required. If less than 4 implants are placed, additional support will be needed from the tissues and greater coverage of the gums is required. This will however still be less than if no implants were used. It has also been shown that biting force is many times more with implants than with dentures and that implants are more suitable support for bridges when many teeth have been lost.
3. Same Day Teeth Replacement
Rationale for immediate tooth replacement
Losing a tooth, especially one of our front teeth can be very distressing for most patients. In addition to the effect on appearance and confidence, it affects our speech and on the long-term, the gums and the supporting jawbone will also shrink. A common request from our patients is to get a replacement for their missing tooth immediately, hence the advent of protocols for "same day teeth replacement". This could be done by partially loading the implant on the day of the surgery, or more commonly by using the adjacent teeth as temporary supports.
How long does it take for healing after tooth extraction and implant surgery
Teeth extraction and implant surgery are fairly routine and painless procedures and you will feel back to normal in just a few days. However, it takes around three months after tooth extraction for the bone to reform before placing an implant. In addition, it takes a further three months for the bone to grow around the implant in order to anchor it firmly in the jaw. During this waiting period, removable dentures, or temporary bridges made of plastic are used to prevent direct forces on the implant allowing the implant to heal.
Can this waiting period be shortened
Yes, it is possible to reduce this waiting period as implants can often be placed immediately into extraction sites for patients with missing front teeth. This reduces the waiting times significantly. In general, we are able to place implants to replace our front teeth on the day of extraction as there is usually adequate bone around and beyond the tooth socket to stabilise the implant. For back teeth, it is not always possible as there is usually insufficient bone after removing the tooth. Very often a bone graft will also be needed and is therefore a more technique sensitive procedure.
Immediately Loaded Implants
If the implant lies firmly within bone, it is possible to even allow partial loading immediately after the surgery. In combination, with the latest computer assisted techniques, it is possible to deliver aesthetic looking temporary teeth in selected cases within 3 hours after the surgery. The patients are however advised to avoid chewing on the implant, especially in the initial weeks after the surgery when the original bone anchoring the implant would have been resorbed with the new bone yet to form.
Is immediate loading of implants a new technique
No, the first controlled study of successful immediate loaded implants was published in 1997 after a successful 10 year study. Our lead clinician has been placing immediately loaded implants since early 1999. The success rate of immediate implants are comparable to that of implants placed using conventional protocols but is more technique sensitive as it requires the dentist to determine if the initial stability of the implant is sufficient for immediate loading. Done selectively, it is a useful option for patients with no other remaining teeth to anchor a temporary denture or bridge.
4. Bone Grafts & Regeneration
A bone graft is a procedure where bone is transferred to an area which is deficient in order to create the bulk necessary to place an implant. Bone graft material can either be harvested from near the implant site, or processed from synthetic or other calcified sources. (for example, specially processed cow bone). They serve as the supporting framework in areas of missing bone. Whatever the source, even if it is your own bone, the body would then initiate its healing process and remodel the graft material into fully functional bone.
Why is there a need to do a bone graft
When teeth are missing or extracted, the jawbone in which it is anchored is lost as well, reducing the amount of support for face and lips creating a sunken and aged appearance. The overlying gum also recedes creating unsightly gaps and spaces between teeth. As bone is required in order to place implants, there is a need to “grow back the bone”. Thankfully, even if teeth have been lost for a long time, implants can still be placed after regenerating the jaw bone using a combination of bone grafts and special membranes.
How long does it take for the bone to grow back?
In general, it takes around 4 months for bone to grow back and regain strength. When powdered bone from a synthetic or alternative source is used, it might take a few additional months for the body to replace it with its own new bone. There is no upper age limit and as long as you are suitable for surgery, it can be performed as the process of bone regeneration will occur even in older individuals. The same principles of healing after a fracture apply, that is the area should be stabilised and left undisturbed, and is free from infection.
How can we speed up the bone regeneration process?
Healing can be speeded up through the use of bone growth factors derived from your own body. Around 20ml of blood is first drawn from your forearm and a special machine, called a centrifuge, used to spin some blood drawn from your vein. This separates blood into different layers. The clear liquid layer, termed PRP (platelet rich plasma), contains cells and factors which promote the regeneration of bone. This is then used in combination with the bone particles to form a spongy like substance which can form the scaffold on which your body regenerates its own bone.
How successful are bone grafts
Bone grafts have a success rate in excess of 90% though it also depends on the experience of the dentist, the size and shape of the defect and also the general health of the patient. Success is lower in areas where it is difficult to create and maintain the space for the bone to grow into such as in the front part of the upper jaw if it has already severely resorbed and in the back of the lower jaw near where the nerve exits the bony canal as it is difficult to manipulate the surrounding tissues. Success may also be affected if the patient is a smoker or in patients with diabetes.
What are sinus lifts and grafts
The maxillary sinuses are air spaces which lie just above and around the roots of our back teeth. When these teeth are lost, the sinus often expands downwards causing severe bone loss. We can gently push the floor of the sinus upwards when we are placing the implant but if the floor has dropped significantly, we may need a surgical procedure to directly access the sinus from the side by creating a small window from which we can push the sinus floor upwards and pack the area below with a big bulk of bone graft material. This will allow implants to be placed in future.
5. Dental Bridge
What are Dental Bridges?
A dental bridge is a long-term replacement for spaces between teeth as the result of tooth loss. The teeth on both sides of the gap are prepared to support a framework on which new teeth are mounted. This is then fixed in position using a special cement and does not need to be removed at night, unlike removable dentures.
Dental bridges are also more stable, comfortable and aesthetically pleasing than dentures. Bridges can be used on natural teeth or dental implants. Bridges last on an average between 7-10 years though some may last for up to 15 years or more
What do we need Dental Bridges?
By replacing missing teeth, dental bridges restore your chewing ability allowing you to have a better choice of foods and is important for both nutrition and digestion. Dental BridgesIt also helps to improve your smile by eliminating unsightly gaps and also by providing lip support to restore your facial contours, profile and proportion, thus contributing to self esteem and confidence.
Dental Bridges also prevent teeth from drifting which would have led to changes in the position and alignment of your teeth.
Types of Dental Bridges
01. Traditional Bridges
As the name implies, a dental bridge is used to close a gap caused by missing teeth. If the span is not too wide, and you have 1 or 2 strong teeth on each side, the teeth can be prepared by removing its outer layer and replacing it with a framework made of metal for support. This is then usually overlaid with a layer of porcelain for better aesthetics. Sometimes, if the gap is very small, we may only need to prepare the tooth on one side, in which case the bridge is called a Cantilever bridge. These are however less stable than conventional bridges.
02. All-porcelain and Zirconia Bridges
All-porcelain and zirconia bridges are similar to traditional bridges in terms of basic design and function and have largely superceded the popularity of traditional metal-based bridges due to the improved aesthetics. They are both strong biomaterials which look natural and feel almost like your own teeth. Between the 2, porcelain has better aesthetics while zirconia is preferred for its strength. In addition, they can now be made using 3D computer technology resulting in a better fit and with far shorter laboratory processing and waiting time.
03. Adhesive Bridges
In some cases, we may be unable to opt for conventional bridges. Adhesive or "Maryland" bridges is a good short to medium term solution for missing teeth. It utilises the two teeth next to the gap for support but instead of preparing the teeth fully, only the back surfaces are roughened or very lightly trimmed to accommodate "wings" or small extensions. While it is a more conservative option than conventional bridges which require the trimming of adjacent teeth, it may sometimes dislodge and is not a good long-term replacement for missing teeth.
04. Implant Bridges
If only one tooth is missing, an implant can be used as a stand-alone solution instead of making a bridge thus avoiding trimming the two teeth adjacent to the missing tooth. Additionally when many teeth are missing, implants can be used to span the gap and support a bridge instead of individually replacing every tooth lost with an implant. This reduces the cost and is also the option if insufficient bone is available. In short an implant dental bridge is similar to a traditional bridge except that it rests on titanium "roots" instead of natural teeth. 5 to 8 implants alone
6. Dentures
Dentures or “false teeth” are a simple and low cost method of replacing missing teeth. They are classified into partial and complete dentures based on whether any teeth remain in the mouth to support and retain them while in use. Prefabricated teeth are attached to a plastic base which may be strengthened by a metal mesh or base and are held in place by wires which grip lightly to the sides of remaining teeth. If all teeth have been lost, the denture will have to rely on a close fit with the gums and soft tissue of the mouth to produce a “suction” effect to keep it in position.
Partial Dentures
The main advantage of dentures is the low cost. A mould is made of your mouth and sent to the laboratory. The missing teeth come prefabricated in a variety of sizes and colour shades and the ones which best fit you are chosen. They are then attached to the plastic base which will carry them and wires which will hold the denture in position. Dentures should be removed at night as they are not hygienic and may cause fungal infection of your gums. In addition small and loose dentures are unsafe as patients have been known to choke on them causing a medical emergency.
Design of a partial denture
The bigger the plate and the more the wires, the more stable the denture becomes. However larger dentures are less comfortable as you may be aware of an object which feels foreign or uncomfortable. In addition the wires may be visible when you smile. To strengthen the base, a metal known as “chrome-cobalt” is used to reduce the thickness while improving the strength of the denture. Dentures without wires to retain them are unsafe as they are usually loose and there is the possibility of these dentures dislodging and the patient choking on them.
Complete or Full Dentures
Complete dentures are made when all our teeth are lost. It is a low cost option and depends on our saliva and natural forces known as “surface tension” to provide the stability. Over time due to the direct pressure of the denture on the underlying soft tissue and bone, the tissues become thinner and the denture becomes loose. In general, lower dentures tend to be less well tolerated by patients as they are usually less stable when compared to upper dentures which have a broader base for support.
It usually takes more than 4 visits to make a denture as a mould must be made of the toothless mouth. As fit is critical at the margins to obtain an effective suction, a second more accurate mould is often required. The dentist will then need to ensure that the dentures made the two separate upper and lower moulds will match each other for proper biting ability. The teeth will also have to be checked for alignment as the position will affect the lip posture and support as well as the amount of teeth shown. Once these have been verified, the denture can then be fabricated in about a week
