A surprising fact is that dental implants have been in practice ever since the ancient times, meaning that their concept is not new, rather their superior materials and forms in modern dentistry are what make them a highly successful treatment today.

The Implant Procedure

The procedure involved in placing dental implants is relatively simple, and can be summarized for clarity in a few basic steps.

· Implant Placement

After the dentist has taken a complete medical and dental history, examined the oral cavity and taken the necessary X-rays needed for accurate implant placement, the patient is ready for the implant.

After administering local anesthesia, the implant is surgically placed within the jaw bone. A small incision is made within the gum to allow access to the underlying bone. A hand- piece or “drill” is then used to make a shallow hole in the bone, within which the implant is then inserted and twisted into place, in the same fashion as a screw. This allows better stability and adaptation of the implant within the bone.

Thereafter, the implant is left and allowed to heal, along with its overlying gum tissue. During this healing period, the core principle of “Osseo- integration” of Titanium implants plays its role, which is the basis for the implant’s success.

Osseo- integration

Implants have been made of a variety of materials ever since they came into existence, ranging from gold- wire, semi- precious stones, iron and ivory. Modern implantology makes use of the biologically friendly and precious metal Titanium.

What makes Titanium unique is its incredible ability to attract bone forming cells around itself. When an implant is placed, it is this phenomenon which gives it superior stability. The bone cells begin to accumulate around the newly placed implant and form new bone, imbedding the implant into this hard tissue firmly. This process is known as “osseo- integration”- integration of the implant in bone – and the core feature of successful Titanium implants.

·         Abutment or Post Placement

The next step in the procedure is a small one, whereby a small post called an abutment is placed into the implant for support of the future prosthesis, such a crown, bridge or denture.

·         Restoration

The final step is the placement and fixation of a dental prosthesis over the implant, to restore the function of the teeth. The restoration can be in the form of a single crown, multiple crowns together known as a bridge and a denture, for its added stability in the mouth.

What Implants can achieve

The purpose of implants in the mouth is to provide a second chance at having a completely functional mouth, and to restore the esthetics that was compromised by the missing tooth or multiple lost teeth. The ability to chew, talk and the general quality of life can all be restored with the help of implants.

Implants can be used to:

• Replace a single tooth with a crown
• Act as anchors to support a fixed bridge, to replace multiple teeth
• As splints to support loose or mobile teeth, preventing unnecessary tooth loss
• Support and give stability for complete dentures, preventing denture dislodge and clicking sounds. This can be achieved by placing multiple implants throughout the edentulous (free of teeth) dental arch.

With the advent of dental implants, dentistry has been able to achieve ground breaking results with fully restoring the function of mouth, helping to improve the quality of life for people all over the globe.

In the 1950s, the Swedish Orthopedic surgeon, Per- Ingvar Branemark discovered the wondrous properties of Titanium, which form the basis of all implants today. He devised the phenomenon of “osseo- integration” of implants which was characteristic of the precious Titanium metal. It was due to this unique property of Titanium that all other metals such as Stainless Steel and Nickel- Chromium alloy implants became outdated, as such materials, though bio- friendly, did not possess the quality of fusion to bone.

Advancements in Implant technology

Ever since the advent of Titanium implants, many advancements in the form of implants have been made. Many different types of implants have been devised but most of them required extensive surgical procedures to placed, and were quite invasive. This would lead to a prolonged healing time for patients and much post- operative discomfort.

It is due to the above mentioned reasons that some implant forms have become obsolete and only two major forms of implants are now approved by the American Dental Association, and are widely used and accepted across globe. These are:

• Endosteal Implants

These are placed directly into the jaw bone are shaped like tiny screws. They give support to dental restorations such as crowns, bridges and even dentures.

• Subperiosteal Implants

These are metal plates or frames which are attached to the bone directly below the gum tissue, which eventually fuse to the surface of bone while healing. They have metal posts which protrude through the gums to support restorations. They are usually used in patients who have insufficient or weak bones.

The conventional implant placement technique has been practiced for many years over the past half century, involving an initial implant placement healing period, a second procedure for placing the supporting post or abutment and finally a third procedure for fabricating and placing the dental prosthesis that the implant is to support.

Though the conventional technique has shown a huge level of success, further efforts to improve the implant technique are constantly being made, along with newer and smaller forms of implants being devised. This is in effort to reduce labor time, reduce healing time, making the placement procedure simpler and to invade the bone as less as possible to achieve the same results as conventional implants.

Nowadays, single visit implants are also being widely practiced, whereby after a non- restorable tooth has been extracted, the implant is placed within the tooth socket right away, rather than waiting for the socket to heal and then to invade the healed socket and re- establish healing for a second time. This makes the entire implant process is much faster as it allows the implant to heal along with the tooth socket, and gives faster osseo- integration results.

The use of the very popular CAD-Cam technology for fabricating dental restorations in a single visit is also practiced in Implantology. This allows 3D images of the implant site to be taken, so that the dental prosthesis to be placed over it can be fabricated right away and attached during the same visit. This method has markedly reduced the waiting time for the dental restoration to be made, along with eliminating the chance of human error during fabrication of the restoration/ prosthesis.

Current research in implant technology focuses on attempting to use the ceramic material Zirconia as implants, as this gives the added benefit of a better match to natural tooth color along with its closeness to the properties of Titanium. It is also a bio-compatible material and is still being studied as a potential new breakthrough in the world of Implantology.

In the event of tooth loss, either in the front or in the back of the mouth, a replacement for the missing tooth is crucial to re-establish the functional integrity of the teeth for vital processes such as chewing and speech, as well as to restore the esthetics of the smile.

Indications of a Dental Implant

Implants are thus meant to replace lost or missing teeth. However, there may be other reasons why one may need a dental implant. The indications of dental implants are listed below.

Missing or lost teeth

Teeth may be lost for reasons such as extensive tooth decay, trauma, periodontal disease and naturally due to old age. In all instances, dental implants may be used to replace the missing tooth or teeth, along with a dental prosthesis such as a crown or bridge to replace one or two teeth, or a denture in the case of complete tooth loss. Implants provide ideal support and retention of these prosthetic appliances.

Painful or Loose dentures

The comfort of wearing complete or partial dentures is a highly variable. Dentures are a conventional method of replacing missing teeth, and have been worn by elderly patients for years. They are one of the most conventional dental prosthesis available. They involve recreating the teeth with an almost natural looking prosthesis consisting of one or multiple acrylic teeth fused to the acrylic denture base.

The entire prosthesis is made of acrylic material and functions mainly through achieving its retention by being seated upon the underlying bone of the gums, along with a suction effect in the mouth aided by saliva. Sometimes a denture may need additional retention through wires incorporated in its structure during fabrication. Having said this, the greatest disadvantage of dentures is the undue load and stress they apply onto supporting bone. Stresses and undue pressure loading lead to unwanted bone resorption, decreasing the level of bone available for retention. This eventually results in a flat jaw bone left over, with no alveolar ridge left for retention. The denture begins to fall off or pop out, which can be very irritating for the patient, who also finds it difficult to talk and chew. The denture also begins to irritate the gums and soft tissues in the mouth, leading to ulcers and sores, making the patient further uncomfortable.

To compensate for these adverse effects of conventional dentures, dental implants can be placed throughout the dental arches to support an entire denture, or even a partial denture. This reduces the stresses applied onto the bone directly and prevents the dislodging of dentures. Furthermore, the implants prevent bone resorption by dentures and preserve the levels of bone around themselves.

Prevention of Jaw Bone Shrinkage

After teeth have been lost from any area of the jaw bones, or even completely from the dental arches,the supporting alveolar bone begins to break down, or resorb. This is due to the lack mechanical stimulation previously provided by the teeth during chewing and general function. The loss of bone results in a flat alveolar ridge and a decreased height in jaw bone relation, resulting in a shorter facial profile which is characteristic of the elderly without teeth.

Implants have the unique ability of attracting bone forming cells, thus promote bone growth around themselves and if placed right after tooth loss, can help to maintain the bone levels of the jaw. They help to prevent bone loss or shrinkage due to their bone forming capabilities.

Considering the high success rates reported for implants, there is still a chance that the implant treatment may fail. The reasons for implant failure are discussed in this article.

Failure of Dental Implants

Implant placement is an intricate procedure that requires much skill and expertise, along with a complete detailed medical and dental history. There are still risks of performing implant surgery, as with any surgical procedure performed elsewhere in the body. Following are some of the main reasons for implant failure.

Overheating of Bone during placement

When an implant is placed in the bone, it needs to be firmly tightened, but this too under highly controlled pressure. Excessive pressure during tightening or implant overloading could cause overheating and subsequent bone death or necrosis, leading to failure of the implant.

Contaminated implant

A contaminated implant would inevitably cause infection around the implant site and within the bone, leading to necrosis and implant failure.

Pre-existing infection/ Post-operative infection

The implant site might be previously infected with foreign material or a remaining root fragment that went undetected or was symptomless, or the sinus above an upper implant site might be infected and could get perforated during the treatment, leading to further subsequent infection and thus, failure of the implant.

Immuno- compromised Patient

A patient with a systemic disease such as uncontrolled diabetes mellitus or liver disease would be most likely to suffer implant failure, this is because their body does not have the required capacity to heal the implant wound and site, causing delayed wound healing leading to failure of the implant and a very high chance of infection at the implant site. Patients under radiation therapy would suffer the same, as would patients with hemophilia, chronic smokers and substance abusers.

Inadequate Oral hygiene

Maintenance of a strict oral hygiene regime is crucial, especially after implant surgery and placement of the restoration. Failure to follow good oral hygiene methods would lead to failure of the implant, as it would cause subsequent peri-implant mucositis and infection of the implant site.

Para-functional habits

After loading the prosthesis upon the implant, bone loss occurs until a steady state of bone formation is achieved. During this period of bone loss, failure of the implant can occur due to excessive biomechanical forces upon the implant by habits such as clenching, grinding or constant chewing.

Primary Implant failure

While placing the implant, the primary implant fit may not be acceptable and could cause the implant to fail. Also, excessive forces and movement of the implant during its healing period would also cause it to be a failed treatment. Care must be taken to ensure that the selected implant is a perfect fit, and that it is not disturbed at all during its healing phase.

Human Error

It is always advised to have implant treatment done by a highly experienced implantologist or any dentist who has a good history of successful implant treatments.  Even then, there is always room for human error and a lack in the implant technique could cause the implant treatment to fail.

Though the above mentioned reasons for implant failure are not very common, they are still a possibility. Always ensure that a thorough medical and dental examination is carried out before considering implant surgery, in order to avoid complications.