what are dental implants

Dental implants are fast emerging and a developing aspect of modern dentistry. Various development in the field of implantology has made it a reliable option for tooth replacement. Implants come in multiple sizes, shapes, and form. Your dentist will decide which type is best suited for you and indicate the implant in accordance.

If you have a single tooth loss, multiple missing teeth or complete edentulous jaw, an implant is a solution to all these problems. Let us understand in detail what are dental implants, its types, and who can get implant procedure.

What are dental implants?

The dental implant is a surgical component which interfaces with the bone of the jaw to support a dental prosthesis or facial prosthesis. A dental prosthesis such as a bridge, crown, or denture can be placed taking the support of a dental implant. Implants are also used as an orthodontic anchor. Typically, dental implants consist of three units –

  • Fixture – this is a screw-shaped structure which forms the major part of the implant body. It is made up of titanium metal which is a bio-compatible material. The screw is placed in the bone of the missing tooth, and it is allowed to heal for three months.
  • Abutment – an abutment acts as an extension that is attached to the fixture.it is usually, a small, stumpy screw that is placed over the fixture above the gum line. Typically, the abutment allows easy access to the implant site. It also acts a support for the temporary or permanent restoration. (1)
  • Dental crown or prosthesis – dental prosthesis for the implant can range from a single crown to a fixed bridge or implant-supported denture. These prothesis replace the missing tooth in them mouth and helps the patient to resume normal functions of chewing, biting and speaking. Additionally, therapeutic appliances improve the aesthetics of the smile.

Dental implants undergo a biologic process called osseointegration, in which materials such as titanium form an intimate bond to bone (2). The implant is first placed so that it is likely to osseointegrate. A variable amount of healing time is indicated for osseointegration depending on many factors. The prosthesis is fabrication undertaken after the stipulated healing period.

History of implants?

The first implant discovery came around 1930s when an archaeologist in Honduras found the mandible of a Mayan woman in her twenties. The mandible contained three tooth-shaped seashells which were inserted into the sockets that once held teeth.

The scientists initially believed that the shells were embedded post-mortem. In 1970, a dental academic discovered that bone had grown around those inserted seashells. This meant that they served as tooth replacements while the woman was still alive.

The father of the modern dental implant, Swedish orthopedic surgeon Per-Ingvar Brånemark, made his implant discovery in the mid-1960s (3). He discovered that bone tissue could fuse to the metal titanium, and he named the process osseointegration.

Over the next several years, many experiments were performed, and various studies were published on the implementation of titanium in bone healing and repair. Eventually, the concept of dental titanium implants grew and was commercialized in 1978.

What causes loss of the tooth?

As mentioned, a Dental implant is a replacement procedure done after the loss of a tooth. Here are the leading causes of tooth loss.

  • Tooth decay
  • Root canal failure
  • Gum disease, Periodontitis (4)
  • Trauma to the mouth
  • Excessive wear and tear
  • Congenital deformities

When is dental implant indicated?

  • A single unit toothless gap with healthy adjacent teeth
  • Partial edentulism with the back (posterior) tooth missing
  • Complete edentulism (5)
  • Patients who cannot tolerate a removable restoration.
  • Patients with high aesthetic and functional demands.

What are the contraindications of dental implants?

  • Heart diseases – affecting the valves, a recent history of infarcts, severe cardiac insufficiency or cardiomyopathy
  • Active cancer, certain bone diseases such as osteomalacia, Paget’s disease, brittle bones syndrome, osteoporosis, etc. (6)
  • Specific immunological disorders, immunosuppressant treatments, clinical AIDS, awaiting an organ transplant
  • Certain mental disorders
  • Strongly irradiated jaw bones, a recent history of radiotherapy
  • Treatments for osteoporosis or some cancers by bisphosphonates
  • Uncontrolled diabetes will lead to implant failure (7)
  • Significant consumption of tobacco, smoking
  • Drug and alcohol dependency
  • Pregnancy
  • Children, the implant is contraindicated until around 18 years of age when the jaw is still in its growing stage (8)

What are the diagnostic steps taken before implant placement?

Implant therapy is an invasive and critical dental treatment that requires proper planning and preparation. Before charting out the complete treatment plan, a dentist or an implant surgeon takes a thorough medical and dental history of the patient to rule out any systemic illness and oral habits that may interfere with the healing process. At this stage, it is essential to ask about any medication that the patient is taking, which may affect the implant procedure.

After taking a thorough history, the dental professional performs a complete oral examination to assess the hygiene status and health of the gums and jaw bone. The radiographic study is ideal to know the height and width of the jaw bone.

Additionally, CT scans help to provide a 3D view of the jaw and its components that may be valuable for the success of the implant procedure. For example, in cases of the insufficient jaw bone, the surgeon may plan for bone graft procedure. Sinus lift procedures are recommended for implant placement in the upper jaw.

Complete blood work is also mandatory to check for patient’s blood sugar levels and the presence of systemic illnesses. All these criteria help the dental professional to evaluate the oral health conditions of the patient and determine the favorability of implant therapy. Moreover, a tentative prognosis of implant success can be pre-determined by assessing the diagnostic findings.

One stage or two-stage surgery?

After an implant placement is done, it is a choice of your dentist to give the prosthesis over the implant immediately or after a waiting period. Either of the following methods does the procedure of implant placement and prosthesis delivery.

Two-Stage procedure

This is the most common method. The implant is surgically placed in the bone so that it lies flush with bone underneath the gum. The site is then closed with stitches to protect the implant from the force while the surrounding bone heals and fuses to it (9). The process of osseointegration is given a period of roughly three to six months.

After the desired period, a second small surgery is conducted to uncover the implant to attach the abutment and fabricate the prosthesis.

Single-Stage procedure

This method involves a long implant, different than the one used in the two-stage procedure, which protrudes through the gum after its placement. After a small stipulated period of a week of fifteen days, the abutment and prosthesis can be placed without any additional surgery to uncover the implant. In some scenarios, same day restoration and prosthesis is provided.

The only disadvantage of this method is that the implant is vulnerable to external forces and care must be taken to make sure that osseointegration occurs (10).

Types of dental implants

Endosteal Implants

These are the most common form of dental implants. Endosteal implants are shaped like screws and are made of titanium. The titanium reduces oxidation and creates a less reactive environment for the implants in the mouth.

After the implant placement is done, it id given time to osseointegration. Depending on the bone quality, underlying health conditions, the osseointegration period varies. After this period, the prosthesis or the artificial teeth can be placed on the implants. Endosteal implants are suited to most patients as an implant treatment option and require a reasonable level of the healthy jawbone.

Subperiosteal Implants

Subperiosteal implants are an alternative to endosteal implants. Rather than being fixed into the jawbone, these implants are placed on top of the bone, but still below the gum. Rather than a firm post entering the bone, a metal frame is fitted under the gum with a post attached to it. As the gum heals around the fixture, the frame is secured and able to have false teeth applied to the posts that protrude from the gum.

These implant procedures are usually suited to people whose jawbone is not sufficient to hold an endosteal implant. These patients may have little bone available for the implant to be placed in, or they may be unwilling/unable to undergo oral surgery to add bone to the area.

Zygomatic implants

Zygomatic implants are mostly placed in the back of the maxillary bone where maxillary sinuses reside. It is indicated when the bone has a low density. The tips of these implants are anchored into the zygomatic bones, which maintain volume and density throughout time, even if the maxillary bone is resorbed.

These implants are recommended for severe maxillary atrophies when there is practically no bone left in the maxilla, or remaining bone is in a meager quantity. Sometimes, due to prolonged edentulous period, the sinus cavity encroaches on the maxillary bone.

Zygomatic implants are an excellent alternative to invasive surgery when the patient is unable or unwilling to undertake complex bone additions for lost bone volume enlargement in this region. Zygomatic implants rapidly and efficiently ensure excellent stability in the posterior area for immediate dental works. Another way to categorize implants is based on their size. The size or the platform dictates where they can be placed in the mouth.

Standard Platform

These implants are best suited for anterior or the front area of the mouth. These are comparatively shorter and narrower implants with a size range from 3.5 mm to 4.2 mm in diameter.

Wide Platform

Wide platform implants are placed primarily in the back of the mouth. They range in size from 4.5 mm to 6 mm in diameter.

Narrow Body

Narrow body dental implants also called mini implants range in size from 2 mm to 3.5 mm in diameter. They are placed primarily in patients with insufficient space between their tooth roots. They are indicated when the patient has inadequate bone density. Implants can also be categorized based on the shape of their head. All implants require the prosthesis and abutment to be screwed or attached to the head.

Internal Hex Connectors

It is shaped like a hexagon; an internal hex connector is an opening in the implant head into which the abutment is screwed.

External Hex Connectors

They are also shaped like a hexagon; these connectors are atop the implant head.

Internal Octagon Connectors

They are shaped like an octagon; an internal octagon connector has an opening in the implant head into which the restoration/abutment is screwed.

Failure of dental implants

In spite of a successful surgery, a dental implant can fail. There are various causes as to why proper osseointegration does not occur. The most common and the most preventable cause is an infection and bone loss around the implant site (11). Peri-implantitis is an infection that forms around the implant and inside the gums. This infection occurs due to poor dental hygiene following dental implant surgery.

Patients with low jawbone density or in patients who suffer dental trauma or uncontrolled diabetes after the implant procedure, the failure chances are high. People who are addicted to smoking and have tobacco or another drug dependence also have a high incidence rate of implant failure. Some of the warning signs for the failure of implant include –

  • Severe gum inflammation
  • Gum recession and exposure of the implant to the oral environment
  • Difficulty in chewing or biting
  • Increased mobility of the implant
  • A gradual increase in pain and discomfort

Let’s take a closer look at the factors that can contribute to implant failure.

Factors that can affect the success of implants

There is a wide range of factors that may not support the implant integration into the jaw bone. Moreover, they help in declining the rate of success. Some of the potential factors are listed below –

Insufficient jaw bone

Often bone loss occurs rapidly in an extracted site. Other causes of bone loss include osteoporosis, aging, periodontal disease, and nutritional deficiency. This affects both the quality and quantity of the bone.

Sufficient jaw bone is one of the most crucial aspects of maintaining implant success. Insufficient jaw bone does not support the implant length and width. Moreover, an attempt to place an implant in this situation may further fracture or weaken the jaw bone.

Gum disease and periodontal breakdown

The health of the gums becomes a crucial aspect of oral health and hygiene when it comes to implant placement. Gums and bone are the prime supporters of the implant in the mouth. Most of the times, gum disease that develops around an implant can lead to increased mobility and failure of the implant in the jaw. Gum disease is a type of oral infection which mainly affects the health of the gums and supporting periodontal tissues. Often people fail to identify the signs of gum disease and ignore this condition.

It is essential to follow regular oral hygiene protocols and take advise from the dentist on extra precautionary measures that may help to maintain the success of an implant. Regular dental check-ups at this point are mandatory to keep a check on oral health and hygiene.

Smoking tobacco

Another factor that can have devastating effects on the gums is smoking tobacco. Tobacco smoking potentially reduces the blood flow to the gums. This effect can significantly decrease the rate of healing after surgical implant placement. (12)

Most of the times, while evaluating the patient’s history during a check-up, the dentist records a history of oral habits. If the patient is a smoker, implant placement is never suggested.

Usually, to make the conditions favorable, dental professionals advise stopping smoking for at least one week before getting a dental implant. Moreover, to maintain the success rate, the patient is advised to not smoke for an additional two months post-implant placement.

Medical health conditions

Often autoimmune diseases like rheumatoid arthritis and diabetes can significantly slow down the healing of the implant site. Furthermore, it can have a negative effect on osteointegration – a process wherein the implant integrates with the surrounding jaw bone.

Many research studies have revealed that taking over-the-counter medications can also have a severe impact on the success rate of an implant. Anti-inflammatory drugs, antidepressants, and medicines for heartburn are some of the typical examples.

Some of the other factors include –

  • Poor oral hygiene – Poor oral hygiene is the main culprit in deteriorating the health of the oral tissues, including the teeth, gums, periodontium, bone, and implant.
  • Inexperienced implant surgeon – it is crucial to select the best and experienced implant surgeon. This is because the placement of an implant requires surgical techniques to integrate the implant into the bone properly. Moreover, care is taken to maintain the health of the gums.

A good implant surgeon is one who can accurately interpret the number of implants required for tooth replacement and plan a treatment that will bring out the fruitful results. Moreover, an experienced implant surgeon is well skilled to prevent iatrogenic trauma to the surrounding delicate oral tissues that may hamper the healing process.

Key points to remember

Dental implant surgery is a minimally invasive procedure. It helps you lead you a comfortable lifestyle despite tooth loss. Implant act as a permanent replacement, and repeated dental work is not required in most of the cases. Selection of the implant depends on the number of missing teeth, the bone strength and density, the location of the missing tooth space, and the knowledge of the implant surgeon.

Several factors should be kept in mind while deciding an implant treatment. Some of these factors include the health of the gums, sufficient jaw bone, habit of smoking tobacco, and the presence of medical health conditions. Maintaining proper dental hygiene is of utmost importance in these cases. Visit your dentist every six months after implant surgery and be regular with brushing and flossing.