Miscellany

Jai Ganesh · Yesterday 00:08:29

2350) Dental Implant

Gist

An implant is a medical device manufactured to replace a missing biological structure, support a damaged biological structure, or enhance an existing biological structure. For example, an implant may be a rod, used to strengthen weak bones.

A dental implant is a metal post that replaces the root portion of a missing tooth. A dental professional places an artificial tooth, also known as a crown, on an extension of the post of the dental implant, giving you the look of a real tooth.

Summary:

Overview

Dental implant, abutment and new tooth in jawbone to replace missing tooth

A dental implant replaces a missing tooth root. Once the implant heals, your dentist can restore it with an artificial tooth.

What are dental implants?

Dental implants are small, threaded posts that surgically replace missing teeth. In addition to filling in gaps in your smile, dental implants improve chewing function and overall oral health. Once healed, implants work much like natural teeth.

A dental implant has three main parts:

* Threaded post: You can think of this like an artificial tooth root. A provider places it in your jawbone during an oral surgery procedure.
* Abutment: This is a tiny connector post. It screws into the threaded post and extends slightly beyond your gums. It serves as the foundation for your new artificial tooth.
* Restoration: A dental restoration is any prosthetic that repairs or replaces teeth. Common dental implant restorations are crowns, bridges and dentures.

Most dental implants are titanium, but some are ceramic. Both materials are safe and biocompatible (friendly to the tissues inside of your mouth).

Missing teeth can take a toll on your oral health. But it also impacts your mental and emotional well-being. Do you avoid social situations? Or cover your mouth when you laugh? Do you rarely smile for photos? Dental implants can restore your smile and your confidence, so you don’t have to miss out on the things you enjoy.

What conditions are treated with dental implants?

Dental implants treat tooth loss, which can happen due to:

* Cavities.
* Cracked teeth.
* Gum disease.
* Teeth that never develop (anodontia).
* Teeth grinding or clenching (bruxism).

How common are dental implants?

Dental implants are a popular choice for tooth replacement. In the United States, dental providers place over 3 million implants each year.

Details

A dental implant (also known as an endosseous implant or fixture) is a prosthesis that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, or facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biological process called osseointegration, in which materials such as titanium or zirconia form an intimate bond to the bone. The implant fixture is first placed so that it is likely to osseointegrate, then a dental prosthetic is added. A variable amount of healing time is required for osseointegration before either the dental prosthetic (a tooth, bridge, or denture) is attached to the implant or an abutment is placed which will hold a dental prosthetic or crown.

Success or failure of implants depends primarily on the thickness and health of the bone and gingival tissues that surround the implant, but also on the health of the person receiving the treatment and drugs which affect the chances of osseointegration. The amount of stress that will be put on the implant and fixture during normal function is also evaluated. Planning the position and number of implants is key to the long-term health of the prosthetic since biomechanical forces created during chewing can be significant. The position of implants is determined by the position and angle of adjacent teeth, by lab simulations or by using computed tomography with CAD/CAM simulations and surgical guides called stents. The prerequisites for long-term success of osseointegrated dental implants are healthy bone and gingiva. Since both can atrophy after tooth extraction, pre-prosthetic procedures such as sinus lifts or gingival grafts are sometimes required to recreate ideal bone and gingiva.

The final prosthetic can be either fixed, where a person cannot remove the denture or teeth from their mouth, or removable, where they can remove the prosthetic. In each case an abutment is attached to the implant fixture. Where the prosthetic is fixed, the crown, bridge or denture is fixed to the abutment either with lag screws or with dental cement. Where the prosthetic is removable, a corresponding adapter is placed in the prosthetic so that the two pieces can be secured together.

The risks and complications related to implant therapy divide into those that occur during surgery (such as excessive bleeding or nerve injury, inadequate primary stability), those that occur in the first six months (such as infection and failure to osseointegrate) and those that occur long-term (such as peri-implantitis and mechanical failures). In the presence of healthy tissues, a well-integrated implant with appropriate biomechanical loads can have 5-year plus survival rates from 93 to 98 percent and 10-to-15-year lifespans for the prosthetic teeth. Long-term studies show a 16- to 20-year success (implants surviving without complications or revisions) between 52% and 76%, with complications occurring up to 48% of the time. Artificial intelligence is relevant as the basis for clinical decision support systems at the present time. Intelligent systems are used as an aid in determining the success rate of implants.

Medical uses

The primary use of dental implants is to support dental prosthetics (i.e. false teeth). Modern dental implants work through a biologic process where bone fuses tightly to the surface of specific materials such as titanium and some ceramics. The integration of implant and bone can support physical loads for decades without failure.

The US has seen an increasing use of dental implants, with usage increasing from 0.7% of patients missing at least one tooth (1999–2000), to 5.7% (2015–2016), and was projected to potentially reach 26% in 2026. Implants are used to replace missing individual teeth (single tooth restorations), multiple teeth, or to restore edentulous (toothless) dental arches (implant retained fixed bridge, implant-supported overdenture). While use of dental implants in the US has increased, other treatments to tooth loss exist.

Dental implants are also used in orthodontics to provide anchorage (orthodontic mini implants). Orthodontic treatment might be required prior to placing a dental implant.

An evolving field is the use of implants to retain obturators (removable prostheses used to fill a communication between the oral and maxillary or nasal cavities). Facial prosthetics, used to correct facial deformities (e.g. from cancer treatment or injuries), can use connections to implants placed in the facial bones. Depending on the situation the implant may be used to retain either a fixed or removable prosthetic that replaces part of the face.

Single tooth implant restoration

Single tooth restorations are individual freestanding units not connected to other teeth or implants, used to replace missing individual teeth. For individual tooth replacement, an implant abutment is first secured to the implant with an abutment screw. A crown (the dental prosthesis) is then connected to the abutment with dental cement, a small screw, or fused with the abutment as one piece during fabrication. Dental implants, in the same way, can also be used to retain a multiple tooth dental prosthesis either in the form of a fixed bridge or removable dentures.

There is limited evidence that implant-supported single crowns perform better than tooth-supported fixed partial dentures (FPDs) on a long-term basis. However, taking into account the favorable cost-benefit ratio and the high implant survival rate, dental implant therapy is the first-line strategy for single-tooth replacement. Implants preserve the integrity of the teeth adjacent to the edentulous area, and it has been shown that dental implant therapy is less costly and more efficient over time than tooth-supported FPDs for the replacement of one missing tooth. The major disadvantage of dental implant surgery is the need for a surgical procedure.

Implant retained fixed bridge or implant supported bridge

An implant supported bridge (or fixed denture) is a group of teeth secured to dental implants so the prosthetic cannot be removed by the user. They are similar to conventional bridges, except that the prosthesis is supported and retained by one or more implants instead of natural teeth. Bridges typically connect to more than one implant and may also connect to teeth as anchor points. Typically the number of teeth will outnumber the anchor points with the teeth that are directly over the implants referred to as abutments and those between abutments referred to as pontics. Implant supported bridges attach to implant abutments in the same way as a single tooth implant replacement. A fixed bridge may replace as few as two teeth (also known as a fixed partial denture) and may extend to replace an entire arch of teeth (also known as a fixed full denture). In both cases, the prosthesis is said to be fixed because it cannot be removed by the denture wearer.

Implant-supported overdenture

A removable implant-supported denture (also an implant-supported overdenture) is a removable prosthesis which replaces teeth, using implants to improve support, retention and stability. They are most commonly complete dentures (as opposed to partial), used to restore edentulous dental arches. The dental prosthesis can be disconnected from the implant abutments with finger pressure by the wearer. To enable this, the abutment is shaped as a small connector (a button, ball, bar or magnet) which can be connected to analogous adapters in the underside of the dental prosthesis.

Orthodontic mini-implants (TAD)

Dental implants are used in orthodontic patients to replace missing teeth (as above) or as a temporary anchorage device (TAD) to facilitate orthodontic movement by providing an additional anchorage point. For teeth to move, a force must be applied to them in the direction of the desired movement. The force stimulates cells in the periodontal ligament to cause bone remodeling, removing bone in the direction of travel of the tooth and adding it to the space created. In order to generate a force on a tooth, an anchor point (something that will not move) is needed. Since implants do not have a periodontal ligament, and bone remodelling will not be stimulated when tension is applied, they are ideal anchor points in orthodontics. Typically, implants designed for orthodontic movement are small and do not fully osseointegrate, allowing easy removal following treatment.[20] They are indicated when needing to shorten treatment time, or as an alternative to extra-oral anchorage. Mini-implants are frequently placed between the roots of teeth, but may also be sited in the roof of the mouth. They are then connected to a fixed brace to help move the teeth.

Small-diameter implants (mini-implants)

The introduction of small-diameter implants has provided dentists the means of providing edentulous and partially edentulous patients with immediate functioning transitional prostheses while definitive restorations are being fabricated. Many clinical studies have been done on the success of long-term usage of these implants. Based on the findings of many studies, mini dental implants exhibit excellent survival rates in the short to medium term (3–5 years). They appear to be a reasonable alternative treatment modality to retain mandibular complete overdentures from the available evidence.

Composition

A typical conventional implant consists of a titanium screw (resembling a tooth root) with a roughened or smooth surface. The majority of dental implants are made of commercially pure titanium, which is available in four grades depending upon the amount of carbon, nitrogen, oxygen and iron contained. Cold work hardened CP4 (maximum impurity limits of N .05 percent, C .10 percent, H .015 percent, Fe .50 percent, and O .40 percent) is the most commonly used titanium for implants. Grade 5 titanium, Titanium 6AL-4V (signifying the titanium alloy containing 6 percent aluminium and 4 percent vanadium alloy) is slightly harder than CP4 and used in the industry mostly for abutment screws and abutments. Most modern dental implants also have a textured surface (through etching, anodic oxidation or various-media blasting) to increase the surface area and osseointegration potential of the implant. If C.P. titanium or a titanium alloy has more than 85% titanium content, it will form a titanium-biocompatible titanium oxide surface layer or veneer that encloses the other metals, preventing them from contacting the bone.

Ceramic (zirconia-based) implants exist in one-piece (combining the screw and the abutment) or two-piece systems - the abutment being either cemented or screwed – and might lower the risk for peri‐implant diseases, but long-term data on success rates is missing.

Additional Information

Dental implant surgery replaces tooth roots with metal, screwlike posts and replaces damaged or missing teeth with artificial teeth that look and work much like real ones. Dental implant surgery can be a helpful choice when dentures or bridgework fit poorly. This surgery also can be an option when there aren't enough natural teeth roots to support dentures or build bridgework tooth replacements.

The type of implant and the condition of the jawbone guide how dental implant surgery is done. This surgery may involve several procedures. The major benefit of implants is solid support for the new teeth — a process that requires the bone to heal tightly around the implant. Because this bone healing requires time, the process can take many months.

Why it's done

Dental implants are surgically placed in your jawbone and serve as the roots of missing teeth. Because the titanium in the implants fuses with your jawbone, the implants won't slip, make noise or cause bone damage like fixed bridgework or dentures might. And the materials can't decay like your own teeth.

Dental implants may be right for you if you:

* Have one or more missing teeth.
* Have a jawbone that's reached full growth.
* Have enough bone to secure the implants or can have a bone graft.
* Have healthy tissues in your mouth.
* Don't have health conditions that can affect bone healing.
* Aren't able or willing to wear dentures.
* Want to improve your speech.
* Are willing to commit several months to the process.
* Don't smoke tobacco.

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