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 various 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.
Dental implants undergo a biologic process called osseointegration, in which materials such as titanium form an intimate bond to bone (1). 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 is 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 (2). 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 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 (3)
- 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 (4)
- 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. (5)
- 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 (6)
- Significant consumption of tobacco, smoking
- Drug and alcohol dependency
- Children, the implant is contraindicated till around 18 years of age when the jaw is still in its growing stage (7)
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.
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 (8). 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.
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 (9).
Types of dental 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 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 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.
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 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 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 insufficient 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 (10). 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 other drug dependence also have a high incidence rate of implant failure.
Key points to remember related to dental implants
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 a repeated dental work is not required in most of the cases. 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.