![Dental-implant-illustration](https://upload.wikimedia.org/wikipedia/commons/1/1d/Dental-implant-illustration.jpg)
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
A dental prosthesis is an intraoral (inside the mouth) prosthesis used to restore (reconstruct) intraoral defects such as missing teeth, missing parts of teeth, and missing soft or hard structures of the jaw and palate. Prosthodontics is the denta ...
such as a
crown
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...
,
bridge
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...
,
denture
Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable (removable partial denture or ...
, or facial prosthesis or to act as an
orthodontic anchor. The basis for modern dental implants is a biologic process called
osseointegration
Osseointegration (from Latin ''osseus'' " bony" and ''integrare'' "to make whole") is the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant ("load-bearing" as defined by Albrekt ...
, in which materials such as
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
or
zirconia
Zirconium dioxide (), sometimes known as zirconia (not to be confused with zircon), is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant stabi ...
form an intimate bond to 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
An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure. Single-span bridges have abutments at each end which provide vertical and lateral support for the span, as well as acting as retaining walls ...
is placed which will hold a dental prosthetic/crown.
Success or failure of implants depends on the health of the person receiving the treatment, drugs which affect the chances of osseointegration, and the health of the tissues in the mouth. The amount of
stress
Stress may refer to:
Science and medicine
* Stress (biology), an organism's response to a stressor such as an environmental condition
* Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
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
Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, th ...
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
A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...
with
CAD/CAM
CAD/CAM refers to the integration of Computer-aided design (CAD) and Computer-aided manufacturing (CAM). Both of these require powerful computers. ''CAD'' software helps designers and draftsmen; ''CAM'' "reduces manpower costs" in the manufactur ...
simulations and surgical guides called
stent
In medicine, a stent is a metal or plastic tube inserted into the lumen of an anatomic vessel or duct to keep the passageway open, and stenting is the placement of a stent. A wide variety of stents are used for different purposes, from expandab ...
s. The prerequisites for long-term success of osseointegrated dental implants are healthy
bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
and
gingiva
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue lini ...
. Since both can
atrophy
Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply t ...
after
tooth extraction
A dental extraction (also referred to as tooth extraction, exodontia, exodontics, or informally, tooth pulling) is the removal of teeth from the dental alveolus (socket) in the alveolar bone. Extractions are performed for a wide variety of reason ...
, pre-prosthetic procedures such as
sinus lift
Maxillary sinus floor augmentation (also termed sinus lift, sinus graft, sinus augmentation or sinus procedure) is a surgical procedure which aims to increase the amount of bone in the posterior maxilla (upper jaw bone), in the area of the prem ...
s or
gingival graft
Gingival grafting, also called gum grafting or periodontal plastic surgery, is a generic term for the performance of any of a number of periodontal surgical procedures in which the gum tissue is grafted. The aim may be to cover exposed root surf ...
s 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 screw
A screw and a bolt (see '' Differentiation between bolt and screw'' below) are similar types of fastener typically made of metal and characterized by a helical ridge, called a ''male thread'' (external thread). Screws and bolts are used to fa ...
s or with
dental cement
Dental cements have a wide range of dental and orthodontic applications. Common uses include temporary restoration of teeth, cavity linings to provide pulpal protection, sedation or insulation and cementing fixed prosthodontic appliances. Recent u ...
. 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), 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
Peri-implantitis is a destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. The soft tissues become inflamed whereas the alveolar bone (hard tissue), which surrounds the implant for the purposes of rete ...
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 make use of
osseointegration
Osseointegration (from Latin ''osseus'' " bony" and ''integrare'' "to make whole") is the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant ("load-bearing" as defined by Albrekt ...
, the 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 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 (see
Missing tooth replacement, Tooth Loss).
Dental implants are also used in
orthodontics
Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, and misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial ...
to provide
anchorage
Anchorage () is the largest city in the U.S. state of Alaska by population. With a population of 291,247 in 2020, it contains nearly 40% of the state's population. The Anchorage metropolitan area, which includes Anchorage and the neighboring Ma ...
(orthodontic mini implants).
An evolving field is the use of implants to retain
obturators (removable prosthesis used to fill a communication between the oral and maxillary or nasal cavities).
Facial prosthetics
A facial prosthetic or facial prosthesis is an artificial device used to change or adapt the outward appearance of a person's face or head.
When used in the theatre, film or television industry, facial prosthetic makeup alters a person's normal f ...
, used to correct facial deformities (e.g. from
cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
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
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...
(the dental prosthesis) is then connected to the abutment with
dental cement
Dental cements have a wide range of dental and orthodontic applications. Common uses include temporary restoration of teeth, cavity linings to provide pulpal protection, sedation or insulation and cementing fixed prosthodontic appliances. Recent u ...
, 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
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...
(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
Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable (removable partial denture or ...
(also an implant supported
overdenture
Overdenture is any removable dental prosthesis that covers and rests on one or more remaining natural teeth, the roots of natural teeth, and/or dental implants. It is one of the most practical measures used in preventive dentistry. Overdentures c ...
) 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
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
in the periodontal ligament to cause
bone remodeling
Bone remodeling (or bone metabolism) is a lifelong process where mature bone tissue is removed from the skeleton (a process called ''bone resorption'') and new bone tissue is formed (a process called ''ossification'' or ''new bone formation''). T ...
, 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.
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
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
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
Titanium alloys are alloys that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness (even at extreme temperatures). They are light in weight, have extraordinary corrosion resistance a ...
(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
An electrolytic cell is an electrochemical cell that utilizes an external source of electrical energy to force a chemical reaction that would not otherwise occur. The external energy source is a voltage applied between the cell′s two electrode ...
or
various-media blasting) to increase the surface area and
osseointegration
Osseointegration (from Latin ''osseus'' " bony" and ''integrare'' "to make whole") is the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant ("load-bearing" as defined by Albrekt ...
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
Titanium oxide may refer to:
* Titanium dioxide (titanium(IV) oxide), TiO2
* Titanium(II) oxide (titanium monoxide), TiO, a non-stoichiometric oxide
* Titanium(III) oxide (dititanium trioxide), Ti2O3
* Ti3O
* Ti2O
* δ-TiOx (x= 0.68–0.75)
* Tin ...
surface layer or veneer that encloses the other metals, preventing them from contacting the bone.
Ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...
(
zirconia
Zirconium dioxide (), sometimes known as zirconia (not to be confused with zircon), is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant stabi ...
-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.
Technique
Planning
General considerations
Planning for dental implants focuses on the general health condition of the patient, the local health condition of the
mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...
s and the jaws and the shape, size, and position of the bones of the jaws, adjacent and opposing teeth. There are few health conditions that absolutely preclude placing implants although there are certain conditions that can increase the risk of failure. Those with poor oral hygiene, heavy smokers and diabetics are all at greater risk for a variant of
gum disease
Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main caus ...
that affects implants called
peri-implantitis
Peri-implantitis is a destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. The soft tissues become inflamed whereas the alveolar bone (hard tissue), which surrounds the implant for the purposes of rete ...
, increasing the chance of long-term failures. Long-term steroid use,
osteoporosis
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone fragility, and consequent increase in fracture risk. It is the most common reason for a broken bone ...
and other diseases that affect the bones can increase the risk of early failure of implants.
It has been suggested that
radiotherapy
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radia ...
can negatively affect the survival of implants. Nevertheless, a systemic study published in 2016 concluded that dental implants installed in the irradiated area of an oral cavity may have a high survival rate, provided that the patient maintains oral hygiene measures and regular follow ups to prevent complications.
Biomechanical considerations
The long-term success of implants is determined, in part, by the forces they have to support. As implants have no periodontal ligament, there is no sensation of pressure when biting so the forces created are higher. To offset this, the location of implants must distribute forces evenly across the prosthetics they support.
Concentrated forces can result in fracture of the bridgework, implant components, or loss of bone adjacent the implant. The ultimate location of implants is based on both biologic (bone type, vital structures, health) and mechanical factors. Implants placed in thicker, stronger bone like that found in the front part of the
bottom jaw have lower failure rates than implants placed in lower density bone, such as the back part of the
upper jaw
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
. People who
grind their teeth also increase the force on implants and increase the likelihood of failures.
The design of implants has to account for a lifetime of real-world use in a person's mouth. Regulators and the dental implant industry have created a series of
tests
Test(s), testing, or TEST may refer to:
* Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities
Arts and entertainment
* ''Test'' (2013 film), an American film
* ''Test'' (2014 film), ...
to determine the long-term mechanical reliability of implants in a person's mouth where the implant is struck repeatedly with increasing forces (similar in magnitude to biting) until it fails.
When a more exacting plan is needed beyond clinical judgment, the dentist will make an acrylic guide (called a stent) prior to surgery which guides optimal positioning of the implant. Increasingly, dentists opt to get a
CT scan
A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...
of the jaws and any existing dentures, then plan the surgery on
CAD/CAM
CAD/CAM refers to the integration of Computer-aided design (CAD) and Computer-aided manufacturing (CAM). Both of these require powerful computers. ''CAD'' software helps designers and draftsmen; ''CAM'' "reduces manpower costs" in the manufactur ...
software. The stent can then be made using
stereolithography
Stereolithography (SLA or SL; also known as vat photopolymerisation, optical fabrication, photo-solidification, or resin printing) is a form of 3D printing technology used for creating models, prototypes, patterns, and production parts in a lay ...
following computerized planning of a case from the CT scan. The use of CT scanning in complex cases also helps the surgeon identify and avoid vital structures such as the
inferior alveolar nerve
The inferior alveolar nerve (IAN) (also the inferior dental nerve) is a branch of the mandibular nerve, which is itself the third branch of the trigeminal nerve. The inferior alveolar nerves supply sensation to the lower teeth.
Structure
The in ...
and the sinus.
Bisphosphonate drugs
The use of bone building drugs, like
bisphosphonates
Bisphosphonates are a class of drugs that prevent the loss of bone density, used to treat osteoporosis and similar diseases. They are the most commonly prescribed drugs used to treat osteoporosis. They are called bisphosphonates because they h ...
and
anti-RANKL drugs require special consideration with implants, because they have been associated with a disorder called
Medication-associated osteonecrosis of the jaw (MRONJ). The drugs change bone turnover, which is thought to put people at risk for death of bone when having minor oral surgery. At routine doses (for example, those used to treat routine osteoporosis) the effects of the drugs linger for months or years but the risk appears to be very low. Because of this duality, uncertainty exists in the dental community about how to best manage the risk of BRONJ when placing implants. A 2009 position paper by the
American Association of Oral and Maxillofacial Surgeons
The American Association of Oral and Maxillofacial Surgeons (AAOMS) is the non-profit professional association serving the specialty of oral and maxillofacial surgery, the surgical arm of dentistry. Its headquarters are in Rosemont, Illinois. , discussed that the risk of BRONJ from low dose oral therapy (or slow release injectable) as between 0.01 and 0.06 percent for any procedure done on the jaws (implant, extraction, etc.). The risk is higher with intravenous therapy, procedures on the lower jaw, people with other medical issues, those on steroids, those on more potent bisphosphonates and people who have taken the drug for more than three years. The position paper recommends against placing implants in people who are taking high dose or high frequency intravenous therapy for cancer care. Otherwise, implants can generally be placed
and the use of bisphosphonates does not appear to affect implant survival.
Main surgical procedures
Placing the implant
Most implant systems have five basic steps for placement of each implant:
# Soft tissue reflection: An incision is made over the crest of bone, splitting the thicker
attached gingiva
"Attached" is the 160th episode of the American science fiction television series ''Star Trek: The Next Generation''. The eighth episode of the Star Trek: The Next Generation (season 7), seventh season. This explores the relationship between two c ...
roughly in half so that the final implant will have a thick band of tissue around it. The edges of tissue, each referred to as a ''flap'' are pushed back to expose the bone. Flapless surgery is an alternate technique, where a small punch of tissue (the diameter of the implant) is removed for implant placement rather than raising flaps.
# Drilling at high speed: After reflecting the soft tissue, and using a surgical guide or stent as necessary, pilot holes are placed with precision drills at highly regulated speed to prevent burning or pressure necrosis of the bone.
# Drilling at low speed: The pilot hole is expanded by using progressively wider drills (typically between three and seven successive drilling steps, depending on implant width and length). Care is taken not to damage the
osteoblast
Osteoblasts (from the Greek language, Greek combining forms for "bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cell (biology), cells with a single Cell nucleus, nucleus that synthesize bone. However, in the p ...
or bone cells by overheating. A cooling
saline or water spray keeps the
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer.
Thermometers are calibrated in various temperature scales that historically have relied o ...
low.
# Placement of the implant: The implant screw is placed and can be
self-tapping,
otherwise the prepared site is tapped with an implant analog. It is then screwed into place with a
torque controlled wrench at a precise
torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
so as not to overload the surrounding bone (overloaded bone can die, a condition called osteonecrosis, which may lead to failure of the implant to fully integrate or bond with the jawbone).
# Tissue adaptation: The
gingiva
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue lini ...
is adapted around the entire implant to provide a thick band of healthy tissue around the ''healing abutment''. In contrast, an implant can be "buried", where the top of the implant is sealed with a ''cover screw'' and the tissue is closed to completely cover it. A second procedure would then be required to uncover the implant at a later date.
Timing of implants after extraction of teeth
There are different approaches to placement dental implants after tooth extraction.
The approaches are:
#Immediate post-extraction implant placement.
#Delayed immediate post-extraction implant placement (two weeks to three months after extraction).
#Late implantation (three months or more after tooth extraction).
An increasingly common strategy to preserve bone and reduce treatment times includes the placement of a dental implant into a recent extraction site. On the one hand, it shortens treatment time and can improve aesthetics because the soft tissue envelope is preserved. On the other hand, implants may have a slightly higher rate of initial failure. Conclusions on this topic are difficult to draw, however, because few studies have compared immediate and delayed implants in a scientifically rigorous manner.
One versus two-stage surgery
After an implant is placed, the internal components are covered with either a healing abutment, or a cover screw. A healing abutment passes through the mucosa, and the surrounding mucosa is adapted around it. A cover screw is flush with the surface of the dental implant, and is designed to be completely covered by mucosa. After an integration period, a second surgery is required to reflect the mucosa and place a healing abutment.
In the early stages of implant development (1970−1990), implant systems used a two-stage approach, believing that it improved the odds of initial implant survival. Subsequent research suggests that no difference in implant survival existed between one-stage and two-stage surgeries, and the choice of whether or not to "bury" the implant in the first stage of surgery became a concern of soft tissue (
gingiva
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue lini ...
) management
When tissue is deficient or mutilated by the loss of teeth, implants are placed and allowed to osseointegrate, then the gingiva is surgically moved around the healing abutments. The down-side of a two-stage technique is the need for additional surgery and compromise of circulation to the tissue due to repeated surgeries.
The choice of one or two-stages, now centers around how best to reconstruct the soft tissues around lost teeth.
Additional surgical procedures
For an implant to
osseointegrate
Osseointegration (from Latin ''osseus'' "bone, bony" and ''integrare'' "to make whole") is the direct structural and functional connection between living bone and the surface of a load-bearing Implant (medicine), artificial implant ("load-bearing ...
, it needs to be surrounded by a healthy quantity of bone. In order for it to survive long-term, it needs to have a thick healthy soft tissue (
gingiva
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue lini ...
) envelope around it. It is common for either the bone or soft tissue to be so deficient that the surgeon needs to reconstruct it either before or during implant placement.
Xenogeneic collagen matrices are used for gingival augmentation after dental implantation.
Hard tissue (bone) reconstruction
''
Bone grafting
Bone grafting is a surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex, pose a significant health risk to the patient, or fail to heal properly. Some small or acute fractures can be cured wit ...
'' is necessary when there is a lack of bone. Also, it helps to stabilize the implant by increasing survival of the implant and decreasing marginal bone level loss. While there are always new implant types, such as short implants, and techniques to allow compromise, a general treatment goal is to have a minimum of 10 mm in bone height, and 6 mm in width. Alternatively, bone defects are graded from A to D (A=10+ mm of bone, B=7–9 mm, C=4–6 mm and D=0–3 mm) where an implant's likelihood of osseointegrating is related to the grade of bone.
To achieve an adequate width and height of bone, various bone grafting techniques have been developed. The most frequently used is called
guided bone graft augmentation where a defect is filled with either natural (harvested or autograft) bone or allograft (donor bone or synthetic bone substitute), covered with a semi-permeable membrane and allowed to heal. During the healing phase, natural bone replaces the graft forming a new bony base for the implant.
Three common procedures are:
#
Sinus lift
Maxillary sinus floor augmentation (also termed sinus lift, sinus graft, sinus augmentation or sinus procedure) is a surgical procedure which aims to increase the amount of bone in the posterior maxilla (upper jaw bone), in the area of the prem ...
# Lateral
alveolar augmentation (increase in the width of a site)
# Vertical alveolar augmentation (increase in the height of a site)
Other, more invasive procedures, also exist for larger bone defects including mobilization of the
inferior alveolar nerve
The inferior alveolar nerve (IAN) (also the inferior dental nerve) is a branch of the mandibular nerve, which is itself the third branch of the trigeminal nerve. The inferior alveolar nerves supply sensation to the lower teeth.
Structure
The in ...
to allow placement of a fixture,
onlay bone grafting using the
iliac crest
The crest of the ilium (or iliac crest) is the superior border of the wing of ilium and the superiolateral margin of the greater pelvis.
Structure
The iliac crest stretches posteriorly from the anterior superior iliac spine (ASIS) to the posterior ...
or another large source of bone and
microvascular bone graft where the blood supply to the bone is transplanted with the source bone and
reconnected
Reconnected may refer to:
*ReConnected, a British vocal group
* "Reconnected" (song), the seventh track of the 2010 Jessica Mauboy album, ''Get 'Em Girls''
*''Reconnected Live
''Reconnected Live'' is a live album by UK synth-pop duo Yazoo, ...
to the local blood supply.
The final decision about which bone grafting technique that is best is based on an assessment of the degree of vertical and horizontal bone loss that exists, each of which is classified into mild (2–3 mm loss), moderate (4–6 mm loss) or severe (greater than 6 mm loss).
Orthodontic extrusion or orthodontic implant site development can be used in selected cases for vertical/horizontal alveolar augmentation.
Soft tissue (gingiva) reconstruction
The
gingiva
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue lini ...
surrounding a tooth has a 2–3 mm band of bright pink, very strong attached mucosa, then a darker, larger area of unattached mucosa that folds into the cheeks. When replacing a tooth with an implant, a band of strong, attached gingiva is needed to keep the implant healthy in the long-term. This is especially important with implants because the blood supply is more precarious in the gingiva surrounding an implant, and is theoretically more susceptible to injury because of a longer attachment to the implant than on a tooth (a longer
biologic width
Crown lengthening is a surgical procedure performed by a dentist, or more frequently a specialist periodontist. There are a number of reasons for considering crown lengthening in a treatment plan. Commonly, the procedure is used to expose a greate ...
).
When an adequate band of attached tissue is absent, it can be recreated with a soft tissue graft. There are four methods that can be used to transplant soft tissue. A roll of tissue adjacent to an implant (referred to as a palatal roll) can be moved towards the lip (buccal),
gingiva from the palate can be transplanted, deeper
connective tissue from the palate can be transplanted or, when a larger piece of tissue is needed, a finger of tissue based on a blood vessel in the palate (called a vascularized interpositional periosteal-connective tissue (VIP-CT) flap) can be repositioned to the area.
Additionally, for an implant to look esthetic, a band of full, plump gingiva is needed to fill in the space on either side of implant. The most common soft tissue complication is called a black-triangle, where the
papilla
Papilla (Latin, 'nipple') or papillae may refer to:
In animals
* Papilla (fish anatomy), in the mouth of fish
* Basilar papilla, a sensory organ of lizards, amphibians and fish
* Dental papilla, in a developing tooth
* Dermal papillae, part of ...
(the small triangular piece of tissue between two teeth) shrinks back and leaves a triangular void between the implant and the adjacent teeth. Dentists can only expect 2–4 mm of papilla height over the underlying bone. A black triangle can be expected if the distance between where the teeth touch and bone is any greater.
Recovery
![Dental-implant](https://upload.wikimedia.org/wikipedia/commons/f/f3/Dental-implant.gif)
The prosthetic phase begins once the implant is well integrated (or has a reasonable assurance that it will integrate) and an abutment is in place to bring it through the mucosa. Even in the event of early loading (less than 3 months), many practitioners will place temporary teeth until osseointegration is confirmed. The prosthetic phase of restoring an implant requires an equal amount of technical expertise as the surgical because of the biomechanical considerations, especially when multiple teeth are to be restored. The dentist will work to restore the
vertical dimension of occlusion
Vertical dimension of occlusion, or VDO, also known as occlusal vertical dimension (OVD), is a term used in dentistry to indicate the superior-inferior relationship of the maxilla and the mandible when the teeth are occluded in maximum intercuspa ...
, the esthetics of the smile, and the structural integrity of the teeth to evenly distribute the forces of the implants.
Healing time
There are various options for when to attach teeth to dental implants,
classified into:
#Immediate loading procedure.
#Early loading (one week to twelve weeks).
#Delayed loading (over three months)
For an implant to become
permanently stable, the body must grow bone to the surface of the implant (
osseointegration
Osseointegration (from Latin ''osseus'' " bony" and ''integrare'' "to make whole") is the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant ("load-bearing" as defined by Albrekt ...
). Based on this biologic process, it was thought that loading an implant during the osseointegration period would result in movement that would prevent osseointegration, and thus increase implant failure rates. As a result, three to six months of integrating time (depending on various factors) was allowed before placing the teeth on implants (restoring them).
However, later research suggests that the initial stability of the implant in bone is a more important determinant of success of implant integration, rather than a certain period of healing time. As a result, the time allowed to heal is typically based on the density of bone the implant is placed in and the number of implants splinted together, rather than a uniform amount of time. When implants can withstand high torque (35
Ncm) and are splinted to other implants, there are no meaningful differences in long-term implant survival or bone loss between implants loaded immediately, at three months, or at six months.
The corollary is that single implants, even in solid bone, require a period of no-load to minimize the risk of initial failure.
Single teeth, bridges and fixed dentures
An abutment is selected depending on the application. In many single crown and fixed partial denture scenarios (bridgework), custom abutments are used. An impression of the top of the implant is made with the adjacent teeth and gingiva. A dental lab then simultaneously fabricates an abutment and crown. The abutment is seated on the implant, a screw passes through the abutment to secure it to an internal thread on the implant (lag-screw). There are variations on this, such as when the abutment and implant body are one piece or when a ''stock'' (prefabricated) abutment is used. Custom abutments can be made by hand, as a cast metal piece or custom milled from metal or zirconia, all of which have similar success rates.
The platform between the implant and the abutment can be flat (buttress) or conical fit. In conical fit abutments, the collar of the abutment sits inside the implant which allows a stronger junction between implant and abutment and a better seal against bacteria into the implant body. To improve the gingival seal around the abutment collar, a narrowed collar on the abutment is used, referred to as
platform switching. The combination of conical fits and platform switching gives marginally better long term periodontal conditions compared to flat-top abutments.
Regardless of the abutment material or technique, an impression of the abutment is then taken and a crown secured to the abutment with dental cement. Another variation on abutment/crown model is when the crown and abutment are one piece and the lag-screw traverses both to secure the one-piece structure to the internal thread on the implant. There does not appear to be any benefit, in terms of success, for cement versus screw-retained prosthetics, although the latter is believed to be easier to maintain (and change when the prosthetic fractures) and the former offers high esthetic performance.
Prosthetic procedures for removable dentures
When a removable denture is worn, retainers to hold the denture in place can be either custom made or "off-the-shelf" (stock) abutments. When custom retainers are used, four or more implant fixtures are placed and an impression of the implants is taken and a dental lab creates a custom metal bar with attachments to hold the denture in place. Significant retention can be created with multiple attachments and the use of semi-precision attachments (such as a small diameter pin that pushes through the denture and into the bar) which allows for little or no movement in the denture, but it remains removable.
However, the same four implants angled in such a way to distribute
occlusal forces may be able to safely hold a fixed denture in place with comparable costs and number of procedures giving the denture wearer a fixed solution.
Alternatively, stock abutments are used to retain dentures using a male-adapter attached to the implant and a female adapter in the denture. Two common types of adapters are the ball-and-socket style retainer and the button-style adapter. These types of stock abutments allow movement of the denture, but enough retention to improve the quality of life for denture wearers, compared to conventional dentures.
Regardless of the type of adapter, the female portion of the adapter that is housed in the denture will require periodic replacement, however the number and adapter type does not seem to affect patient satisfaction with the prosthetic for various removable alternatives.
Maintenance
After placement, implants need to be cleaned (similar to natural teeth) with a
periodontal scaler
Periodontal scalers are dental instruments used in the prophylactic and periodontal care of teeth (most often human teeth), including scaling and root planing. The working ends come in a variety of shapes and sizes, but they are always narrow at ...
to remove any
plaque
Plaque may refer to:
Commemorations or awards
* Commemorative plaque, a plate or tablet fixed to a wall to mark an event, person, etc.
* Memorial Plaque (medallion), issued to next-of-kin of dead British military personnel after World War I
* Pla ...
. Because of the more precarious blood supply to the gingiva, care should be taken with dental floss. Implants will lose bone at a rate similar to natural teeth in the mouth (e.g. if someone has periodontal disease, an implant can be affected by a similar disorder) but will otherwise last. The
porcelain
Porcelain () is a ceramic material made by heating substances, generally including materials such as kaolinite, in a kiln to temperatures between . The strength and translucence of porcelain, relative to other types of pottery, arises mainl ...
on crowns should be expected to discolour, fracture or require repair approximately every ten years, although there is significant variation in the service life of dental crowns based on the position in the mouth, the forces being applied from opposing teeth and the restoration material. Where implants are used to retain a complete denture, depending on the type of attachment, connections need to be changed or refreshed every one to two years.
An
oral irrigator
An oral irrigator (also called a dental water jet, water flosser or, by the brand name of the best-known such device, Waterpik) is a home dental care device which uses a stream of high-pressure pulsating water intended to remove dental plaque a ...
may also be useful for cleaning around implants.
The same kinds of techniques used for cleaning teeth are recommended for maintaining hygiene around implants, and can be manually or professionally administered.
Examples of this would be using soft toothbrushes or nylon coated interproximal brushes.
The one implication during professional treatment is that metal instruments may cause damage to the metallic surface of the implant or abutment, which can lead to bacterial colonisation.
So, to avoid this, there are specially designed instruments made with hard plastic or rubber. Additionally rinsing (twice daily) with antimicrobial mouthwashes has been shown to be beneficial.
There is no evidence that one type of antimicrobial is better than the other.
Peri-implantitis is a condition that may occur with implants due to bacteria, plaque, or design and it is on the rise.
This disease begins as a reversible condition called peri-implant mucositis but can progress to peri-implantitis if left untreated, which can lead to implant failure.
People are encouraged to discuss oral hygiene and maintenance of implants with their dentists.
There are different interventions if peri-implantitis occurs, such as mechanical debridement, antimicrobial irrigation, and antibiotics. There can also be surgery such as open-flap debridement to remove bacteria, assess/smooth implant surface, or decontaminate implant surface.
There is not enough evidence to know which intervention is best in the case of peri-implantitis.
Risks and complications
During surgery
Placement of dental implants is a surgical procedure and carries the normal risks of surgery including infection, excessive bleeding and
necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...
of the flap of tissue around the implant. Nearby anatomic structures, such as the
inferior alveolar nerve
The inferior alveolar nerve (IAN) (also the inferior dental nerve) is a branch of the mandibular nerve, which is itself the third branch of the trigeminal nerve. The inferior alveolar nerves supply sensation to the lower teeth.
Structure
The in ...
, the
maxillary sinus
The pyramid-shaped maxillary sinus (or antrum of Highmore) is the largest of the paranasal sinuses, and drains into the middle meatus of the nose through the osteomeatal complex.Human Anatomy, Jacobs, Elsevier, 2008, page 209-210
Structure
It is ...
and blood vessels, can also be injured when the
osteotomy
An osteotomy is a surgical operation whereby a bone is cut to shorten or lengthen it or to change its alignment. It is sometimes performed to correct a hallux valgus, or to straighten a bone that has healed crookedly following a fracture. It is ...
is created or the implant placed.
Even when the lining of the maxillary sinus is perforated by an implant, long term
sinusitis
Sinusitis, also known as rhinosinusitis, is inflammation of the nasal mucosa, mucous membranes that line the paranasal sinuses, sinuses resulting in symptoms that may include thick Mucus#Respiratory system, nasal mucus, a nasal congestion, plugg ...
is rare.
An inability to place the implant in bone to provide stability of the implant (referred to as primary stability of the implant) increases the risk of failure to
osseointegration
Osseointegration (from Latin ''osseus'' " bony" and ''integrare'' "to make whole") is the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant ("load-bearing" as defined by Albrekt ...
.
First six months
Primary implant stability
Primary implant stability refers to the stability of a dental implant immediately after implantation. The stability of the
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
screw
A screw and a bolt (see '' Differentiation between bolt and screw'' below) are similar types of fastener typically made of metal and characterized by a helical ridge, called a ''male thread'' (external thread). Screws and bolts are used to fa ...
implant in the patient's
bone tissue
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, an ...
post surgery may be non-invasively assessed using
resonance frequency analysis Resonance frequency analysis (RFA) is a method used to determine stability (the level of osseointegration) in dental implants. The stability is presented as an implant stability quotient (ISQ) value. The higher the ISQ value the higher the stabilit ...
. Sufficient initial stability may allow immediate loading with
prosthetic
In medicine, a prosthesis (plural: prostheses; from grc, πρόσθεσις, prósthesis, addition, application, attachment), or a prosthetic implant, is an artificial device that replaces a missing body part, which may be lost through trau ...
reconstruction, though early loading poses a higher risk of implant failure than conventional loading.
The relevance of primary implant stability decreases gradually with regrowth of bone tissue around the implant in the first weeks after surgery, leading to secondary stability. Secondary stability is different from the initial stabilization, because it results from the ongoing process of bone regrowth into the implant (
osseointegration
Osseointegration (from Latin ''osseus'' " bony" and ''integrare'' "to make whole") is the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant ("load-bearing" as defined by Albrekt ...
). When this healing process is complete, the initial mechanical stability becomes biological stability. Primary stability is critical to implantation success until bone regrowth maximizes mechanical and biological support of the implant. Regrowth usually occurs during the 3–4 weeks after implantation. Insufficient primary stability, or high initial implant mobility, can lead to failure.
Immediate post-operative risks
# Infection (pre-op antibiotics reduce the risk of implant failure by 33 percent but do not affect the risk of infection).
# Excessive bleeding
# Flap breakdown (less-than 5 percent)
Failure to integrate
An implant is tested between 8 and 24 weeks to determine if it is integrated. There is significant variation in the criteria used to determine implant success, the most commonly cited criteria at the implant level are the absence of pain, mobility, infection, gingival bleeding, radiographic lucency or peri-implant bone loss greater than 1.5 mm.
Dental implant success is related to operator skill, quality and quantity of the bone available at the site, and the patient's
oral hygiene
Oral hygiene is the practice of keeping one's mouth clean and free of disease and other problems (e.g. bad breath) by regular brushing of the teeth (dental hygiene) and cleaning between the teeth. It is important that oral hygiene be carried out ...
, but the most important factor is
primary implant stability
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 (dentistry), crown, bridge (dentistry), bridge, dentures, denture, ...
.
While there is significant variation in the rate that implants fail to integrate (due to individual risk factors), the approximate values are 1 to 6 percent
Integration failure is rare, particularly if a dentist's or oral surgeon's instructions are followed closely by the patient. Immediate loading implants may have a higher rate of failure, potentially due to being loaded immediately after trauma or extraction, but the difference with proper care and maintenance is well within statistical variance for this type of procedure. More often, osseointegration failure occurs when a patient is either too unhealthy to receive the implant or engages in behavior that contraindicates proper dental hygiene including
smoking
Smoking is a practice in which a substance is burned and the resulting smoke is typically breathed in to be tasted and absorbed into the bloodstream. Most commonly, the substance used is the dried leaves of the tobacco plant, which have bee ...
or drug use.
Long term
The long-term complications that result from restoring teeth with implants relate, directly, to the risk factors of the patient and the technology. There are the risks associated with appearance including a high smile line, poor gingival quality and missing papillae, difficulty in matching the form of natural teeth that may have unequal points of contact or uncommon shapes, bone that is missing, atrophied or otherwise shaped in an unsuitable manner, unrealistic expectations of the patient or poor oral hygiene. The risks can be related to
biomechanical factors, where the geometry of the implants does not support the teeth in the same way the natural teeth did such as when there are cantilevered extensions, fewer implants than roots or teeth that are longer than the implants that support them (a poor
crown-to-root ratio
Crown-to-root-ratio is the ratio of the length of the part of a tooth that appears above the alveolar bone versus what lies below it. It is an important consideration in the diagnosis, treatment planning and restoration of teeth, one that hopefully ...
). Similarly,
grinding of the teeth, lack of bone or low diameter implants increase the biomechanical risk.
Finally there are technological risks, where the implants themselves can fail due to fracture or a loss of retention to the teeth they are intended to support.
Long-term failures are due to either loss of bone around the tooth and/or gingiva due to
peri-implantitis
Peri-implantitis is a destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. The soft tissues become inflamed whereas the alveolar bone (hard tissue), which surrounds the implant for the purposes of rete ...
or a mechanical failure of the implant. Because there is no
dental enamel
Tooth enamel is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, ...
on an implant, it does not fail due to
cavities
Cavity may refer to:
Biology and healthcare
*Body cavity, a fluid-filled space in many animals where organs typically develop
**Gastrovascular cavity, the primary organ of digestion and circulation in cnidarians and flatworms
*Dental cavity or too ...
like natural teeth. While large-scale, long-term studies are scarce, several systematic reviews estimate the long-term (five to ten years) survival of dental implants at 93–98 percent depending on their clinical use.
During initial development of implant retained teeth, all crowns were attached to the teeth with screws, but more recent advancements have allowed placement of crowns on the abutments with dental cement (akin to placing a crown on a tooth). This has created the potential for cement, that escapes from under the crown during cementation to get caught in the gingiva and create a peri-implantitis (see picture below). While the complication can occur, there does not appear to be any additional
peri-implantitis
Peri-implantitis is a destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. The soft tissues become inflamed whereas the alveolar bone (hard tissue), which surrounds the implant for the purposes of rete ...
in cement-retained crowns compared to screw-retained crowns overall.
In compound implants (two stage implants), between the actual implant and the superstructure (abutment) are gaps and cavities into which bacteria can penetrate from the oral cavity. Later these bacteria will return into the adjacent tissue and can cause periimplantitis.
Criteria for the success of the implant supported dental prosthetic varies from study to study, but can be broadly classified into failures due to the implant, soft tissues or prosthetic components or a lack of satisfaction on the part of the patient. The most commonly cited criteria for success are function of at least five years in the absence of pain, mobility, radiographic lucency and peri-implant bone loss of greater than 1.5 mm on the implant, the lack of suppuration or bleeding in the soft tissues and occurrence of technical complications/prosthetic maintenance, adequate function, and esthetics in the prosthetic. In addition, the patient should ideally be free of pain,
paraesthesia
Paresthesia is an abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. Paresthesia may be transient or chronic, and may have any of dozens of possible underlying causes. Paresthesias ar ...
, able to chew and taste and be pleased with the esthetics.
The rates of complications vary by implant use and prosthetic type and are listed below:
Single crown implants (5-year)
# Implant survival: 96.8 percent
# Crown survival: metal-ceramic: 95.4 percent; all-ceramic: 91.2 percent; cumulative rate of ceramic or acrylic veneer fracture: 4.5 percent
#
Peri-implantitis
Peri-implantitis is a destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. The soft tissues become inflamed whereas the alveolar bone (hard tissue), which surrounds the implant for the purposes of rete ...
: 9.7 percent
up to 40 percent
#
Peri-implant mucositis Peri-implant mucositis is defined as an inflammatory lesion of the peri-implant mucosa in the absence of continuing marginal bone loss.
The American Academy of Periodontology defines peri‐implant mucositis as a disease in which inflammation of th ...
: 50 percent
# Implant fracture: 0.14 percent
# Screw or abutment loosening: 12.7 percent
# Screw or abutment fracture: 0.35 percent
Fixed complete dentures
# Progressive vertical bone loss, but still in function (Peri-implantitis): 8.5 percent
# Failure after the first year 5 percent at five years, 7 percent at ten years
# Incidence of veneer fracture at:
#::''5-year'': 13.5
to 30.6 percent,
#::''10-year'': 51.9 percent (32.3 to 75.5 percent with a
confidence interval
In frequentist statistics, a confidence interval (CI) is a range of estimates for an unknown parameter. A confidence interval is computed at a designated ''confidence level''; the 95% confidence level is most common, but other levels, such as 9 ...
at 95 percent)
#::''15-year'': 66.6 percent (44.3 to 86.4 percent with a confidence interval at 95 percent)
# 10-year incidence of framework fracture: 6 percent (2.6 to 9.3 percent with a confidence interval at 95 percent)
# 10-year incidence of esthetic deficiency: 6.1 percent (2.4 to 9.7 percent with a confidence interval at 95 percent)
# prosthetic screw loosening: 5 percent over five years
to 15 percent over ten years
The most common complication being fracture or wear of the tooth structure, especially beyond ten years
with fixed dental prostheses made of metal-ceramic having significantly higher ten-year survival compared those made of gold-acrylic.
Removable dentures (overdentures)
# Loosening of removable denture retention: 33 percent
# Dentures needing to be relined or having a retentive clip fracture : 16 to 19 percent
History
![Branemark's initial radiograph](https://upload.wikimedia.org/wikipedia/commons/4/47/Branemark%27s_initial_radiograph.jpg)
There is
archeological
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscape ...
evidence that humans have attempted to replace missing teeth with root form implants for thousands of years. Remains from ancient China (dating 4000 years ago) have carved bamboo pegs, tapped into the bone, to replace lost teeth, and 2000-year-old remains from ancient Egypt have similarly shaped pegs made of precious metals. Some Egyptian mummies were found to have transplanted human teeth, and in other instances, teeth made of ivory.
Etruscans produced the first pontics using single gold bands as early as 630 BC and perhaps earlier.
Wilson Popenoe
Frederick Wilson Popenoe (March 9, 1892 – June 20, 1975) was an American Department of Agriculture employee and plant explorer. From 1916 to 1924, Popenoe explored Latin America to look for new strains of avocados. He reported his adventur ...
and his wife in 1931, at a site in Honduras dating back to 600 AD, found the lower
mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
of a young
Mayan
Mayan most commonly refers to:
* Maya peoples, various indigenous peoples of Mesoamerica and northern Central America
* Maya civilization, pre-Columbian culture of Mesoamerica and northern Central America
* Mayan languages, language family spoken ...
woman, with three missing incisors replaced by pieces of
sea shells
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer usually created by an animal or organism that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washe ...
, shaped to resemble teeth.
Bone growth around two of the implants, and the formation of calculus, indicates that they were functional as well as esthetic. The fragment is currently part of the Osteological Collection of the
Peabody Museum of Archaeology and Ethnology
The Peabody Museum of Archaeology and Ethnology is a museum affiliated with Harvard University in Cambridge, Massachusetts. Founded in 1866, the Peabody Museum is one of the oldest and largest museums focusing on anthropological material, with ...
at Harvard University.
In modern times, a tooth replica implant was reported as early as 1969, but the polymethacrylate tooth analogue was encapsulated by soft tissue rather than osseointegrated.
The early part of the 20th century saw a number of implants made of a variety of materials. One of the earliest successful implants was the Greenfield implant system of 1913 (also known as the Greenfield crib or basket).
Greenfield's implant, an iridioplatinum implant attached to a gold crown, showed evidence of osseointegration and lasted for a number of years.
The first use of titanium as an implantable material was by Bothe, Beaton and Davenport in 1940, who observed how close the bone grew to titanium screws, and the difficulty they had in extracting them.
Bothe et al. were the first researchers to describe what would later be called osseointegration (a name that would be marketed later on by
Per-Ingvar Brånemark
Per-Ingvar Brånemark (May 3, 1929 – December 20, 2014) was a Swedish physician and research professor, acknowledged as the "father of modern dental implantology". The ''Brånemark Osseointegration Center'' (BOC), named after its founder, was fo ...
). In 1951, Gottlieb Leventhal implanted titanium rods in rabbits.
Leventhal's positive results led him to believe that titanium represented the ideal metal for surgery.
In the 1950s research was being conducted at
Cambridge University
, mottoeng = Literal: From here, light and sacred draughts.
Non literal: From this place, we gain enlightenment and precious knowledge.
, established =
, other_name = The Chancellor, Masters and Schola ...
in England on blood flow in living organisms. These workers devised a method of constructing a chamber of
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
which was then embedded into the
soft tissue
Soft tissue is all the tissue in the body that is not hardened by the processes of ossification or calcification such as bones and teeth. Soft tissue connects, surrounds or supports internal organs and bones, and includes muscle, tendons, ligam ...
of the ears of
rabbit
Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...
s. In 1952 the Swedish
orthopaedic surgeon
Orthopedic surgery or orthopedics ( alternatively spelt orthopaedics), is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal ...
,
Per-Ingvar Brånemark
Per-Ingvar Brånemark (May 3, 1929 – December 20, 2014) was a Swedish physician and research professor, acknowledged as the "father of modern dental implantology". The ''Brånemark Osseointegration Center'' (BOC), named after its founder, was fo ...
, was interested in studying bone healing and regeneration. During his research time at
Lund University
, motto = Ad utrumque
, mottoeng = Prepared for both
, established =
, type = Public research university
, budget = SEK 9 billion [Leonard Linkow
Leonard I. Linkow (February 25, 1926 – January 26, 2017) was an American dentist and pioneer in the field of oral implantology. In 1969, he was nominated for a Nobel Prize in medicine, making him the only dentist to be nominated for the prize. ...]
, in the 1950s, was one of the first to insert titanium and other metal implants into the bones of the jaw. Artificial teeth were then attached to these pieces of metal. In 1965 Brånemark placed his first titanium dental implant into a human volunteer. He began working in the mouth as it was more accessible for continued observations and there was a high rate of
missing teeth in the general population offered more subjects for widespread study. He termed the clinically observed adherence of bone with titanium as "osseointegration".
Since then implants have evolved into three basic types:
# Root form implants; the most common type of implant indicated for all uses. Within the root form type of implant, there are roughly 18 variants, all made of
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
but with different shapes and surface textures. There is limited evidence showing that implants with relatively smooth surfaces are less prone to peri-implantitis than implants with rougher surfaces and no evidence showing that any particular type of dental implant has superior long-term success.
#
Zygoma The term zygoma generally refers to the zygomatic bone, a bone of the human skull commonly referred to as the cheekbone or malar bone, but it may also refer to:
* The zygomatic arch, a structure in the human skull formed primarily by parts of the z ...
implant; a long implant that can anchor to the
cheek bone
In the human skull, the zygomatic bone (from grc, ζῠγόν, zugón, yoke), also called cheekbone or malar bone, is a paired irregular bone which articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It is si ...
by passing through the
maxillary sinus
The pyramid-shaped maxillary sinus (or antrum of Highmore) is the largest of the paranasal sinuses, and drains into the middle meatus of the nose through the osteomeatal complex.Human Anatomy, Jacobs, Elsevier, 2008, page 209-210
Structure
It is ...
to retain a complete upper denture when bone is absent. Whil
zygomatic implantsoffer a novel approach to severe bone loss in the
upper jaw
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
, it has not been shown to offer any advantage over
bone grafting
Bone grafting is a surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex, pose a significant health risk to the patient, or fail to heal properly. Some small or acute fractures can be cured wit ...
functionally although it may offer a less invasive option, depending on the size of the reconstruction required.
#Small diameter implants are implants of low diameter with one-piece construction (implant and abutment) that are sometimes used for denture retention or orthodontic anchorage.
See also
*
Carl E. Misch
*
Dennis P. Tarnow
Dennis Perry Tarnow (b. May 28) is an American dentist specializing in dental implant research. He is director of implant dentistry at Columbia University College of Dental Medicine and a speaker on the subject of implant dentistry.[Leonard Linkow
Leonard I. Linkow (February 25, 1926 – January 26, 2017) was an American dentist and pioneer in the field of oral implantology. In 1969, he was nominated for a Nobel Prize in medicine, making him the only dentist to be nominated for the prize. ...]
*
Per-Ingvar Brånemark
Per-Ingvar Brånemark (May 3, 1929 – December 20, 2014) was a Swedish physician and research professor, acknowledged as the "father of modern dental implantology". The ''Brånemark Osseointegration Center'' (BOC), named after its founder, was fo ...
References
Further reading
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{{DEFAULTSORT:Dental Implant
Implants (medicine)
Dentistry
Restorative dentistry
Prosthetics
Oral surgery
Dental equipment
Prosthodontology