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.
What are the different ways of replacing missing teeth
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.
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.
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.
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.
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.
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. It 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.
They also prevent teeth from drifting which would have led to changes in the position and alignment of your teeth. It is also important in speech as gaps, spaces or unstable dentures will lead to lisping as we speak.
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.
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.