dentist
logo image
dentist

Dental Implants,
the complete patient's guide

author icon By Dr. George Ghidrai

Today, dental implants are the state-of-the-art tooth replacement systems and are now more common than ever before.

In the past, implants often failed. Now, the typical life of an implant is about 15 years or longer. About 95% of implants today are successful.

dental implant

Dental implants are a highly debatable subject in dentistry. In later years, because of the ever-increasing demand for dental implants, implantology has experienced a spectacular development and the technology continues to improve.

The industry has also focused on reducing treatment time and some implants can be placed immediately after tooth extraction as opposed to waiting six months after extraction.

In this article, we aim to offer you a complete guide that tries to deal with all the important aspects of dental implant treatments.

The guide is primarily intended for patients who are planning to have dental implants, but it may prove very useful to anyone searching for information on this topic.


Summary


Top

What are dental implants?

Dental implants are metal devices that are surgically inserted into the jawbone in order to replace one or more missing teeth.

Normally, dental implants support a dental prosthesis such as a crown, bridge, removable dentures but sometimes they may act as orthodontic anchors (in order to align and straighten teeth).


dental implant-supported bridge

implant-supported bridge

dental implant-supported denture

implant-supported denture


First, a surgical procedure is required to place the dental implant inside the jawbone. The basis for modern dental implants is a biologic process called osseointegration where materials, such as titanium, form an intimate bond to bone. A variable amount of healing time is required for osseointegration (3 to 6 months).

After the healing time, an abutment is attached to the implant. The abutment will hold the dental prosthesis (crown, bridge, removable denture).


dental implant structure


Why are dental implant restorations superior?

A lot of patients may wonder why they should choose dental implants (which entail a higher cost) over traditional dental restorations supported on natural teeth.

The great advantage of a dental implant is that it replaces the missing tooth in the most natural way possible. Dental implants "fuse" with the bone thanks to the biological process called osseointegration.

Thanks to this process, implant-supported prostheses offer a variety of advantages compared to conventional restorations.

The main objective of any dental restoration is the proper replacement of the missing teeth.

Teeth have 3 functions: Chewing, Aesthetics, and Pronunciation. When a dental restoration is designed, one of the main goals is to restore these functions as close as possible to natural teeth.

Let's compare implant restorations to traditional restoration in rehabilitating teeth's main functions:


  • Mastication or chewing process

    Mastication is the most important dental process. When a restoration is designed, it is important to rehabilitate this process as closely as possible to natural teeth. When this goal is achieved, patients will adapt very quickly to the new restoration.

    When an implant-supported denture is manufactured, the chewing forces are passed to the surrounding bone just as in the case of natural teeth (see left image). Consequently, chewing comfort is excellent because dental implants function remarkably like natural teeth.


    dental implant chewing forces

    chewing forces in case of a dental implant

    removable denture chewing forces

    chewing forces in case of a removable dentures


    By contrast, when a traditional denture is designed, some of the chewing forces are passed to the underneath gums as dentures usually rest exclusively on the gums. This is not the natural way, hence it takes longer to get used to a removable denture.


  • Aesthetics

    Restoring aesthetics is for many patients the most important goal. The general aesthetic of an implant-supported reconstruction is great. A dental implant restores a lost tooth so that it looks, feels, fits, and functions almost like a natural tooth.


    dental implants: restoring aesthetics

    restoring aesthetics with
    two implant-supported crowns


  • Phonation or pronunciation

    The normal speech can be disturbed when upper front teeth are missing (particularly incisors). It is well known that these teeth have an important role in some consonants pronunciation.

    Adjusting to traditional removable dentures can mean struggling to pronounce everyday words, at least until mouth tissues adapt to the new situation (which can take several weeks). Not so with dental implants, which function almost like natural teeth.


Other important advantages

  • Dental implants reduce the load on the remaining oral structures (teeth, gums, jawbone) by offering independent support and retention to crowns, bridges and removable dentures.

  • Dental implants preserve natural tooth tissue by avoiding the need to prepare adjacent teeth for conventional restorations (for example, a traditional dental bridge).

    Tooth preparation involves permanently removing parts of the tooth's original structure, including portions that might still be healthy and structurally sound.

    dental implant against dental bridge

    single tooth gap: if a traditional dental bridge is designed, the preparation of the adjacent teeth is required


    dental implant against dental bridge

    single tooth gap: if an implant-supported crown is manufactured, the adjacent teeth remain untouched


  • Dental implants will preserve bone and significantly reduce bone resorption and deterioration that results in loss of jawbone height.

  • Implant supported dentures may allow chewing the food better and speaking more clearly. Studies have shown that these prostheses contribute to improved chewing efficiency and speaking, compared to full dentures.

    overdenture supported by dental implants

    implant-supported denture

    full denture

    full denture



Dental implants drawbacks

If there are no general or local contraindications, dental implants have few drawbacks.


Indications

Dental implants are the state-of-the-art tooth replacement systems. Dental implants can successfully restore all forms of partial edentulism (one or several teeth are missing) and complete edentulism (all teeth from a dental arch are missing).

Here are some situations when dental implants are strongly indicated:

  • Single unit toothless gap with healthy adjacent teeth

    When a single tooth is missing, an implant-supported crown will preserve the adjacent natural teeth by avoiding the need to prepare them. If the toothless gap is restored with a traditional dental bridge, both adjacent teeth will have to be prepared.

    This operation involves permanently removing parts of the teeth's original structure, including portions that might still be healthy and structurally sound.


    dental implant indication: single unit toothless gap

    single unit toothless gap

    dental implant-supported crown

    an implant-supported crown is the best treatment option



  • Partial edentulism with the back (posterior) tooth missing

    These conditions imply the absence of several posterior teeth (molars and/or premolars) on one or both sides of the dental arch (Kennedy class 1 or Kennedy class 2).

    In these cases, traditional dental bridges (supported by natural teeth) are difficult to design because the back support tooth is missing. Removable partial dentures generally require the preparation of several teeth.

    Implant supported prostheses, although entailing a higher cost, are highly indicated in these clinical situations.


    dental implants indication: posterior teeth missing


  • Complete edentulism

    When all teeth are missing, the only traditional solution available is a full removable denture.

    Implant supported prosthesis (either fixed or removable) allow to chew the food better, speak more clearly and they have a superior stability.

    overdenture supported by dental implants

    implant-supported
    removable denture

    full denture

    full denture


  • Other situations when dental implants may be indicated

    • Patients who cannot tolerate a removable restoration (removable denture).
    • Patients with high aesthetic and/or functional demands.


Contraindications

General contraindications

  1. Absolute contraindications

    Some serious general conditions make anesthesia, surgical procedures and the overall placement inadvisable.

    • Heart diseases affecting the valves, recent infarcts, severe cardiac insufficiency, cardiomyopathy
    • Active cancer, certain bone diseases (osteomalacia, Paget's disease, brittle bones syndrome, etc.)
    • Certain immunological diseases, immunosuppressant treatments, clinical AIDS, awaiting an organ transplant
    • Certain mental diseases
    • Strongly irradiated jaw bones (radiotherapy treatment)
    • Treatments of osteoporosis or some cancers by bisphosphonates

  2. Relative contraindications

    Other situations will be evaluated on a case-by-case basis. Most often, dental implants can only be placed (with the greatest caution) after some preliminary treatments.

    • Diabetes (particularly insulin-dependent)
    • Angina pectoris (angina)
    • Significant consumption of tobacco
    • Certain mental diseases
    • Certain auto-immunes diseases
    • Drug and alcohol dependency
    • Pregnancy

Age

  • Children: not before the jaw bones have stopped growing (in general 17-18 years).
  • On the other hand, advanced age does not pose problems if the patient's general condition is good.

Local contraindications

Some conditions or physiological changes, usually inside the mouth cavity, may temporarily prevent the placement of dental implants. Most of the times, these conditions can be remedied before the implants are inserted in the jawbone.

  • There is insufficient bone to support the implants or bone structure is inadequate (due to some chronic infections or other conditions). To ensure a good prognosis, a dental implant must be surrounded by healthy bone tissue.


    dental implant schematic

    a dental implant must be surrounded
    by healthy bone tissue (with red)


  • Important anatomical structures such as the maxillary sinus, the inferior alveolar nerve (located inside the mandible), have an abnormal position that can interfere with the dental implants.


    dental implants temporary contraindication: maxillary sinus lowering

    lowering of the maxillary sinus

    Adjunctive surgical procedures have to be performed before the placement of dental implants. These procedures aim to increase the amount of bone, so more bone is available to support the implants.

  • Some local diseases of the oral mucosa or alveolar bone can temporarily prevent the placement of dental implants until the conditions are treated.

  • Hypersensitivity or other allergic reactions; rarely occurs.

  • Poor oral hygiene.

  • Bruxism or involuntary grinding of the teeth.


What is the structure of a dental implant restoration?

Most often, a dental implant restoration consists of 3 parts:

dental implant restoration structure

  1. Dental implant - A surgical component that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge or removable denture.

    A surgical procedure is required to place the dental implant inside the jawbone. One or more implants may be required for a specific case.

    For example, when a single tooth is missing, a single implant will be positioned. If all teeth from a dental arch are missing, 4 to 8 implants may be required to support the restoration.

  2. Abutment - Implant abutments are artificial devices that are connected to the dental implants after the healing process is over.

    The abutments are used to attach a crown, bridge, or removable denture to the implant fixtures.

  3. Prosthetic device - Dental implants can support a large variety of prosthetic devices: dental crowns, dental bridges and various types of implant-supported removable dentures.


1. Dental implant

Dental implants come in a variety of shapes and sizes, so there is one to suit every clinical situation. An implant is actually an "artificial tooth root"; the implant surface is ribbed for better integration into bone tissue.


dental implants

dental implants

Implants are also threaded; when they are screwed into the bone, they collect bone tissue so that the implant is as stable as possible when it integrates into the bone.

Some implants are molded as one piece with the crown; in this case, the type of the crown is pre-determined. More often, an abutment is attached to the implant after the healing period; this allows for more fine-tuning.

Manufacturing material

Most often, dental implants are made of titanium. Titanium is the most favored material by most of the dental clinicians and implant manufacturing companies due to its high biocompatibility, non-allergic and tissue friendly nature and its great ability to make a connection of its surface with the alveolar bone for the process of osseointegration.

Besides titanium, zirconium dental implants have lately emerged. Even though they are relatively new, there has been a considerable increase in the use of these dental implants.


dental implant materials


2. Abutment

Abutments are manufactured in a range of sizes and shapes and are usually delivered by manufacturing companies along with the implants. From the various range of abutments, the ones that best fit the clinical case are selected.

implant abutment

Manufacturing materials

Implant abutments can be made from a variety of materials, such as titanium, surgical stainless steel, gold and, more recently, zirconium.

  • Titanium abutments

    Titanium abutments are widely used due to the excellent properties of the titanium alloys. They have a very good strength and biocompatibility and can be used for any type of prosthetic restoration.

    titanium abutments

    titanium abutments

    Most clinicians feel more comfortable using a metal prosthetic abutment in the posterior molar areas, due to the increased masticatory forces present in these areas.

  • Zirconium abutments

    Zirconium abutments are more modern abutments, which are used to better complement the aesthetics of a dental implant restoration.

    When all ceramics or zirconium restorations are planned, zirconium implant abutments provide a highly desirable option. When a zirconium abutment is used, the problem of matching the shade of adjacent teeth while hiding the dark color of the metal abutment is avoided.

    Moreover, in 2011, a one-piece zirconia implant (fixture and abutment) was introduced into the market.

    dental implant abutments manufacturing materials


  • Other materials

    Besides titanium and zirconium, artificial abutments can be made of other materials: gold alloy, stainless steel etc. Although indications are narrower, there are situations in which these may be successfully utilized.

zirconium abutments

zirconium abutments

gold abutments

gold abutments



How is an implant abutment selected?

When the practitioner selects the abutments, several factors are involved:

  • The type of prosthesis that is executed: crown, fixed bridge or removable denture

  • How the restoration is attached to the abutments: with dental cement, with lag-screws or with special retainers

  • The position of the implant inside the mouth cavity: generally, larger artificial abutments are positioned in the back of the mouth because of the increased chewing forces


3. Implant supported prostheses

Dental implants can support a large variety of prosthetic devices. When planning for a type of implant-supported restoration, several factors are involved:

  • The number and position of missing teeth
  • The overall clinical conditions
  • Aesthetic and functional demands
  • Geographical location: different types of prostheses can be designed in various parts of the world
  • Whether a patient can afford the designed solution
  • The expertise and preferences of each practitioner

Dental crown

An implant-supported crown is normally indicated when a single tooth is missing. However, it is possible to design adjacent single unit crowns when several teeth are missing.


dental implant-supported crown

The dental crowns can be made of porcelain fused to metal alloys (gold, titanium, base metals), zirconia or all ceramics. The time of execution is relatively short and the prognosis is very good.


Dental bridge

Many patients prefer fixed implant-supported bridges because they do not have to be removed for cleaning. Bridges are permanently secured to the implants either with dental cement or with lag-screws. Large dental bridges supported by many implants can be quite expensive.


dental implant-supported bridge

It is not advisable to design dental bridges that are supported by both natural teeth and dental implants (with some exceptions). This could lead to the loosening of the implants (because of natural teeth physiologic mobility) and failure.

implant-supported bridge, chewing forced

The graphic above shows an implant in a bridge connection with a natural tooth. The movability of the tooth causes the chewing forces to act as a lever on the rigid implant situation.

It is also important to design enough implant units to adequately support the bridge. For example, if all teeth are missing and a fixed dental bridge is designed, at least 6 implants are required to support the bridgework.


Dentures

An implant-supported denture is a type of overdenture that is supported by and attached to implants. An implant-supported denture should be daily removed, to clean the denture and gum area.


dental implant-supported denture

Compared to a traditional denture (full denture) which rests exclusively on the gums, implant supported dentures allow chewing the food better, speaking more clearly and provide a better stability.

Removable dentures are designed when a large number (most of the times, all) of teeth are missing. When a removable denture is worn, retainers to hold the denture in place are attached to the implants and the denture.

Special retainers

Most often, the retainers are made of two components:

implant-supported dentures adapter or retainer
  • A male-adapter attached to the implant

  • A female adapter housed in the denture. This part will require periodic replacement.

special retainer abutments: male-adapters attached to the implants

the male-adapters
are attached to the implants

special retainer abutments: female-adapters are housed in the denture

the female-adapters
are housed in the denture


There are various types of adapters designed to hold overdentures in place: the ball-and-socket style retainer (image above) and the button-style adapter are just two examples.

Another variation is when a cast bar of metal is secured to the implants. The complete denture then attaches to the bar with attachments allowing no movement of the denture (image below).


overdenture supported by dental implants


Orthodontic anchors

Dental implants can be used as orthodontic anchors in order to align teeth. Orthodontic implants are different from the ones used for prosthetics, as there is no osseointegration. Mini-implants provide absolute anchorage and they have revolutionized the field of orthodontics.


Planning for dental implants

In the presence of healthy tissues, well integrated dental implants with appropriate biomechanical loads can have long term success rates: 93 to 98 percent for the fixture and 10 to 15 years lifespan for the prosthetic teeth.

For this, proper planning is essential. The medical examination and the imaging methods allow the practitioner to devise a treatment plan that will give the implant-supported prosthesis the best prognosis.


a. Medical examination

The medical examination will have to focus on all the important issues, from general health conditions to local conditions, the assessment of bone support, the soft tissue structure etc.

The medical examination involves the taking of the medical history - an account of the symptoms as experienced by the patient, followed by the physical examination.


b. Imaging methods

Imaging methods such as X-rays or CT scans are vital tools in devising the treatment plan. Imaging methods will give precise information that the practitioner can use and details that are impossible to detect during the medical examination.

Other imaging methods are available like an ultrasound or magnetic resonance imaging (MRI) scan. These do not use radiation.


c. Treatment plan

An accurate treatment plan will have a positive impact on the success rate of the implant fixtures and the lifespan of the prosthetic device. That is why this is probably the most important step of the entire treatment.

When the treatment plan is designed, all the important issues will have to be considered:

These are the main steps of a properly devised treatment plan.


Dental implant procedure

After the treatment plan has been devised, all surgical and prosthetic procedures are clearly established. As a result, the implant procedure is ready to go. Several steps are involved:


The treatment of all existing conditions

It is essential that before any surgical procedures, all structures inside the mouth cavity are healthy or properly treated. Otherwise, there is a great risk of failure.

These operations should be completed before any surgery takes place.


Adjunctive surgical procedures

For an implant to osseointegrate, it needs to be surrounded by a healthy quantity of bone.

dental implant schematic

a dental implant must be surrounded
by healthy bone tissue (with red)

If the size and/or structure of the bone is not adequate to support the designed implants, adjunctive surgical procedures are planned to increase the amount of bone.

Other adjunctive procedures aim to recreate the soft tissues that surround the implants or to reposition anatomical structures that might interfere with the dental implants.

maxillary sinus lowering

lowering of the maxillary sinus
sinus lift is indicated before the implants are placed


While there are many types of adjunctive procedures, these are the most common:

  • Sinus lift is a surgical procedure which aims to increase the amount of bone in the upper jaw, in the area of premolar and molar teeth, by sacrificing some of the volume of the maxillary sinus.

  • Bone graft is a surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex or to increase the amount of bone in a particular site for various reasons.

    In dental implantology, both procedures are used to increase the amount of bone, so more bone is available to support the implants.

  • Soft tissue reconstruction (or gum graft) is a surgical procedure that aims to cover an area of exposed tooth root surface or dental implant with grafted oral tissue.

    When replacing a tooth with an implant, a band of strong, attached gingiva is needed to keep the implant healthy in the long-term.

  • Alveolar nerve repositioning is a complex surgical procedure that is used when the inferior alveolar nerve (located inside the mandible), has an abnormal position that can interfere with the dental implants.

Depending on the clinical conditions, these procedures are performed either before (more often) the base procedure or during implant placement.


Dental implant surgery

The surgical placement of dental implants is a painless procedure that can last a variable time (from 10 min to 2 hours) depending on how many implants are inserted.

Dental implant procedure is normally performed by the oral surgeon or another specialized physician under local anesthesia. However, in some cases, general anesthesia can also be used.

Timing of implants after extraction of teeth

There are different approaches to placement of dental implants after tooth extraction:

  • Immediate post-extraction implant placement

    An increasingly common strategy to preserve bone and reduce treatment time 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. This approach can only be used in specific situations and patients need to be carefully evaluated for their suitability.

  • Delayed immediate post-extraction implant placement

    The implant is placed two weeks to three months after extraction. The procedure requires some type of bone grafting to create a bony base for the implant.

  • Late implantation

    The surgery is performed three months or more after tooth extraction. It is the most prudent approach; during this time, the body will grow new bone inside the alveolar socket (where the tooth was formerly held).


Surgery technique

Most implant systems have five basic steps for placement of each implant.

  1. Soft tissue reflection

    The aim of this step is to expose the bone in the area where the implant is placed. An incision is made over the crest of bone splitting the soft tissue. The edges of tissue, each referred to as a flap are pushed back to expose the bone.


    dental implant procedure: soft tissue reflection

    soft tissue reflection

    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.


  2. Drilling

    For this operation, specific titanium burs are utilized. A cooling saline or water spray keeps the temperature low to prevent bone damage caused by overheating.

    • To guide optimal positioning of the implants, a guidance stent can be utilized

      guidance stent during implant surgery

      guidance stent

    • Pilot holes are placed with precision drills at highly regulated speed to prevent burning or pressure necrosis of the bone

    • The pilot holes are expanded by using progressively wider drills, typically between three and seven successive drilling steps, depending on implant width and length.

      dental implant surgery: drilling

      drilling

    • The last drill used matches implant dimensions (width and length)


  3. Placement of the implants

    The implant is screwed into place at a precise torque so as not to overload the surrounding bone (which may cause osteonecrosis and the failure of the implant). A specific screw-key is utilized for the operation.

    dental implant procedure: placement of the implant phase 1

    placement of the implant phase 1

    dental implant procedure: placement of the implant phase 2

    placement of the implant phase 2


  4. Soft tissue adaptation

    After placement of the implant, a specific healing device is screwed into the implant. There are 2 possible alternatives:

    • Healing abutment

      The healing abutment passes through the mucosa, and the surrounding mucosa is adapted around it.

      dental implant healing abutment

      healing abutment

    • Cover screw

      The cover screw is flush with the surface of the dental implant and is designed to be completely covered by mucosa. A second procedure would then be required to uncover the implant at a later date (two-stage procedure).

    The choice of one or two-stage procedure centers on how best to reconstruct the soft tissues around lost teeth.

    The gingiva is adapted around the entire implant to provide a thick band of healthy tissue around the healing abutment. When a cover screw is used, the implant is "buried" and the tissue is closed to completely cover it.


  5. Temporary restoration

    When the procedure is completed, a temporary restoration is constructed especially if the implants are loaded (with the prosthetic device) after more months.

    The temporary restoration will replace the missing teeth during the biological process of osseointegration (which may take more than 3 months).


After the operation

After the surgical procedure, some medication may be prescribed (depending on each case): pain relievers, anti-inflammatory medication, antibiotics etc.

It is advisable to protect the areas where the procedure was performed in the early days after surgery. A proper and thorough oral hygiene is essential.

Most often, there are no major side effects. Bruising and swelling of the gums and face, pain, and minor bleeding are not uncommon - and not necessarily indicate that something has gone wrong. However, it's wise to keep the surgeon apprised of those symptoms.

Sutures are usually removed after 7-10 days. During this appointment, the doctor will assess the healing process.

Placement of dental implants is a surgical procedure and carries the normal risks of surgery.


Healing and Osseointegration

For an implant to become permanently stable, the body must grow bone to the surface of the implant. This process is called osseointegration.

Osseointegration is defined as the formation of a direct interface between an implant and bone, without intervening soft tissue. Applied to oral implantology, this means that the bone grows right up to the implant surface without interposed soft tissue layer.

osseointegration

When osseointegration occurs, the implant is tightly held in place by the bone. The process typically takes several weeks or months and it can be influenced by several factors:

  • Implant material

    For osseointegrated dental implants, metallic, ceramic (zirconia), and polymeric materials have been used, in particular, titanium. Up to this day, titanium is the most favored material due to its great ability to make a connection of its surface with the alveolar bone.

  • Overload

    Generally speaking, osseointegration can be damaged by prolonged adverse stimuli and overload, which may result in implant failure.

The fact is that the degree of osseointegration of implants is a matter of time. While first evidence of integration occurs after a few weeks, the more robust connection is progressively effected over the next months or years.

This means that the osseointegration process continues well after the definitive restoration is secured to the implants.

That is just one reason why the prosthetic phase requires an equal amount of technical expertise: a restoration that overloads one (or more) implants can damage the osseointegration process, which may result in implant failure.


Loading time

Loading time refers to when are the artificial teeth attached to the implants. Do not confuse loading time with the timing of implants after extraction of teeth, which is a different matter.

There are three valid options for when to attach teeth to dental implants:


Same day dental implants vs traditional procedure

As patient demand for immediate gratification has increased, implant dentistry has focused on reducing treatment time and some implants can be placed and loaded immediately after tooth extraction.

To better understand this new approach, let's follow a clinical case:

damaged tooth

broken front tooth that can no longer be restored

same day dental implant

after tooth removal, a dental implant is placed to restore the gap

One of the many benefits of dental implants is replacing a broken or damaged tooth in the front area that can no longer be restored. In this case, an implant crown offers a highly aesthetic and efficient solution as it avoids the need to prepare the adjacent teeth.

However, the traditional procedure can take up to one year as it implies three different steps:

  1. Removal of the existing tooth or root. The extraction socket is left to heal for four to six months before a dental implant is placed. During this period, the body will grow new bone inside the socket.

  2. The implant is surgically inserted into the jaw bone. A variable amount of healing time is required for osseointegration (3 to 6 months).

  3. After the healing time, a dental crown is attached to the implant.

Immediate placement and loading

Same day dental implants or immediate implants means immediate implant placement after extraction followed by immediate loading of the crown.

Nowadays immediate loading is becoming far more common: the dental implant, abutment, and temporary crown are placed within 48 hours of implant surgery and are left in position for the healing period.

Immediate placement is not appropriate for all patients and cases and the screening process should be extremely thorough. For a complete guide to immediate dental implants, follow this link.


Prosthetic phase

The prosthetic phase begins once the implant is well integrated or has a reasonable assurance that it will integrate. 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 have to be restored.

The dentist will work to restore a functional bite (or occlusion), the aesthetics of the smile, and the structural integrity of the teeth to evenly distribute the forces of the implants.

Several steps are involved:

1. Removing the temporary restorations

The temporary restorations are removed from the mouth. In some situations, these can be reused during the execution of the definitive prosthesis.


2. Testing the degree of osseointegration

The first criteria to be considered are the absence of pain, clinical mobility, infection and gingival bleeding.

The Periotest is a specific device that measures the degree of implant mobility inside the bone. It has the advantage of measuring the levels of subclinical mobility using an ultrasonically vibrating probe.

The Periotest is successful in assessing the stability status of an implant, but it can detect the quantity of bony osseointegration only in terminal cases (that means 3 to 6 months after the implant placement).

Therefore, it is advisable to combine this test with a dental radiography; radiography proved to be a more sensitive method of determining the degree of bone formation (or loss) around a dental implant.

periotest

Periotest

periapical radiography dental implant

periapical radiography:
a well integrated dental implant

In conclusion, periapical radiographs in addition to the Periotest device were found to offer the most reliable assessment of an implant osseointegration status.


3. Removing the healing devices

After the placement of implants, a healing device was attached to each implant.

  • If a healing abutment was used, simply unscrewing it with a small key makes the removal.
  • If a cover screw was positioned, a second procedure is needed to uncover the implant. The incision is very simple and painless.

4. Attaching the implant abutments

Implant abutments are artificial devices that are connected to the dental implants after the healing process and are then used to attach the prosthetics to the implant fixtures.

Abutments come in a wide range of sizes and shapes and the ones that best fit the clinical case are selected. Generally, the selection is done when the treatment plan is devised, before the surgical placement (but this is not a general rule).

implant abutment

how is the abutment attached

implant abutments various types

implant abutments of various types


After the selection, the abutments are attached to the implant fixtures with lag-screws. There are some variations on this, such as when the abutment and implant body are one piece or when a custom made abutment is used.

Another variation 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.


5. The dental impression

The impression is made after the abutments are attached to the implants. Regardless of the size of the restoration, a complete impression (that captures all teeth and surrounding structures) of both dental arches is taken.

complete impression for an implant-supported denture

complete impression for
an implant-supported denture

In some variations, after the impression, the abutment is unscrewed from the implant and sent to the dental lab along with the impressions.


6. Bite registration

The bite registration captures the relationship between the upper and the lower teeth. The long-term success of implants is determined, in part, by the forces they have to support. Therefore, restoring a proper occlusion (or bite) is one of the most important goals.

It is essential not to overload the implants with additional pressures and to evenly distribute the chewing forces of the implants. Otherwise, there is a high risk of failure.

Many times the usual bite registration techniques do not provide enough data for the dental technician. As a result, in some situations, particularly when a large restoration is designed, it is advisable to use advanced jaw tracking devices that provide additional details.

jaw tracking device

jaw tracking device

The jaw tracking devices provide details about the precise position of the maxilla and mandible against different anatomical structures of the head. This information is extremely useful when manufacturing large restorations that need to be extremely accurate.


7. Dental laboratory stages

All the impressions, along with the bite registration and other important details are sent to the dental laboratory. The dental technician will fabricate the designed prosthesis according to the specifications received from the dental office.

Laboratory stages were detailed in a separate chapter. The lab stages for constructing an implant restoration are largely the same as in the case of traditional restorations, but high precision is required.


8. Fitting

Before the restoration is definitively attached to the dental implants, one or more fitting appointments may be needed. During these appointments, the practitioner checks how well the prosthesis fits and makes the necessary adjustments if the fitting is not perfect.

The dentist will first check the fitting of the framework; after porcelain build-up, the shape, size and general appearance of the prosthesis are also tested.

framework fitting for an implant-supported denture phase 1
framework fitting for an implant-supported denture phase 2

framework fitting for an implant-supported denture

The bite adjustment is an essential step. This is a vital element, as a dysfunctional environment created by an inaccurately adjusted implant-supported restoration can lead to the implants' failure.


9. Attaching the prosthesis

This final step is performed when the definitive restoration is completed and ready to be secured to the implants. Depending on the type of prosthesis, this particular step may be different:

a. Fixed prosthesis

A fixed prosthesis is when a person cannot remove the denture or teeth from their mouth. Where the prosthetic is fixed, the crown, bridge or denture is fixed to the abutment with either lag-screws or cement.

  • Prosthesis is attached with lag-screws

    The restoration is secured with screws that traverse the dental crowns and attach to the threaded holes inside the abutments. After the screws are positioned, the holes that penetrate the crowns are sealed with a composite material.

    artificial abutment with a threaded hole

    artificial abutment with a threaded hole

    implant crown secured with a lag-screw

    the crown is secured with a lag-screw

    Another variation 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.

  • Prosthesis is secured with dental cement

    In this case, the restoration is secured with dental cement, just like crowns and bridges are attached to natural teeth.


b. Removable dentures

Removable dentures are held in place by special adapters (or retainers). Generally, a male-adapter is attached to the implant and a female-adapter is housed in the denture.

special retainer abutments: male-adapters attached to the implants

the male-adapters
are attached to the implants

special retainer abutments: female-adapters are housed in the denture

the female-adapters
are housed in the denture

The retainers allow movement of the denture (that should be daily removed, to clean the denture and gum area), but enough retention to improve the quality of life for denture wearers, compared to conventional dentures.


Immediate care:

  • protect the part with the restoration in the early days
  • thorough oral hygiene
  • report any discomfort
  • the first periodic checkup at no more than 6 months

Immediate followup

After the prosthesis is definitively attached to the implants, it takes a little time for the dental tissues to adapt to the new situation. Therefore, some minor reactions may occur.

Most often, the symptoms gradually disappear after a period of time or after simple adjustments performed at the dental office.

  • Light pain in the gums

    In many cases, the practitioner will try to hide the margin of the restoration. The line is an unsightly thing to have exposed, so the dentist would like to place the margin below the gum line.

    Because of that, some patients may feel mild pain at this level until the gum tissue adapts to the new situation. Usually, the pain goes away after several days without any medication (although some mild pain relievers may be prescribed).


  • Pain or discomfort when chewing

    If patients experience pain or discomfort when biting down on something, most often the bite needs to be readjusted. The same is true when patients feel that a part of the restoration is "too high".

    In these cases, it is very important to consult the dentist. It is essential that the prosthesis perfectly fits in the bite so all chewing forces are evenly distributed on the implants.


  • Removable dentures

    New removable dentures or overdentures may feel awkward for few weeks until the body becomes accustomed to them. Dentures are generally larger than fixed restorations (crowns, bridges), so the dental tissues need time to adapt.

    It is not unusual to experience minor irritation or soreness in the early days. When small lesions (image below) appear on the mucosa, the removable denture needs minor adjustments performed at the dental office.

    removable denture soreness

    The saliva flow may temporarily increase. As the mouth becomes accustomed to the dentures, these problems should go away.

    Follow-up appointments with the dentist are generally needed after a denture is inserted so the fit can be checked and adjusted. If any problem persists, particularly irritation or soreness, it is advisable to contact the dentist.

Generally, it takes time to get used to any new restoration. However, after a period of time, the implant-supported prosthesis should look, function, and feel like regular teeth.


Care and maintenance

Dental implants require regular professional maintenance as well as proper home care. Taking good care of dental implants is vital for long-term success.

  • Oral hygiene

    Proper and thorough oral hygiene is a prerequisite for successful dental implant rehabilitations. A poor oral hygiene greatly increases the risk of failure.

    After placement, implants need to be cleaned (similar to natural teeth) with a Teflon instrument (or a similar one) to remove any plaque. Because of the more precarious blood supply to the gingiva, care should be taken with dental floss.

    Fixed implant restorations (crowns, bridges) should be carefully cleaned as well. For example, a bridge should be brushed at least twice a day with a fluoride paste and cleaned between the teeth and under the bridge with dental floss, interdental cleaners, and water jet.

    dental implant care: implant cleaned with a Teflon instrument

    dental implant cleaned with a Teflon instrument

    dental implant care: implant-supported crown flossing

    implant-supported crown: flossing

    Removable dentures supported by implants should be daily removed and cleaned separately. Special attention should be given to the underneath gum area.


  • Periodic monitoring

    Regular checkups should be conducted at least twice a year. During checkups, the practitioner assesses the overall situation, verifies implants stability and integration, the status of the prosthetic devices and makes the necessary adjustments.

    The oral mucosa is checked and professional teeth cleaning and tartar scaling is performed. The patients should report any pain, discomfort or unusual signs.


  • Implant rehabilitations should not be overloaded

    Implant supported prosthesis should not be used in an exaggerated manner. It is advisable to avoid biting on extremely hard pieces of food: peanuts or pistachios, very hard bread crumbs, etc.

    Besides that, there are conditions that can be extremely harmful to dental implants and the prosthetic devices. For example, bruxism or teeth grinding is a condition that involves involuntary habitual grinding of the teeth, typically during sleep.

    It is advisable that patients contact the doctor as soon as they notice the first signs of such conditions.


  • Maintenance of removable dentures

    Removable dentures and overdentures require continuous maintenance. The female adapters that are housed in the denture need to be changed or refreshed every one to two years because they wear off. The operation is extremely simple and quick.

    Relining

    Relining or rebasing is indicated when a removable denture fit has worsened resulting in an unstable denture or tissue trauma. A denture reline involves refitting of the tissue side of the denture to custom fit to the mouth.

    A removable denture fit can worsen due to 2 possible causes:

    • The manufacturing material (normally acrylic) from the base of the denture has worn off or/and
    • The bone beneath the denture underwent a process of remodeling and has diminished its height


    dental implant maintenance: removable denture relining

    removable denture relining

    Relining consists of replacing the fitting surface with a new material, usually cold or heat cured acrylic or tissue conditioner. This can be carried out directly (at the dental office) or, more often, indirectly (at the dental lab). The procedure takes little time (1 session) and it is not very expensive.


Risks and complications

Every medical procedure carries some risks and dental implants are no exception. Accidents and complications may occur during various stages of the treatment. Generally, dental implants risks and complications can be divided into 3 distinct groups:

  • Risks and complications during implant surgery

    Placement of dental implants is a surgical procedure and carries the normal risks of surgery. If additional surgical procedures are performed (sinus lift, bone graft etc.), they also carry the normal risks.

    However, the risk of complications is considered to be very low - less than 5 percent, according to current statistics. Problems are rare and when they do occur, they are usually minor and easily treated.

  • Risks and complications in the first 6 months

    These complications occur in the first 6 months after implant placement. The most common complication is the failure to integrate

  • Long term complications

    Long-term implant failures may be caused by an improper design of the prosthetic restoration or by inappropriate care and maintenance. Regardless of the cause, implants fail due to either loss of bone around them or a mechanical failure of the implant.

    There are also the risks associated with the prosthetic components which over time can wear off, chip, break or cause a lack of satisfaction on the part of the patient.


Patients who wear implant-supported prosthesis should ideally be free of pain or any other unpleasant signs, able to chew and taste and be pleased with the aesthetics.

Implants should be tested at least twice a year during regular checkups. Criteria for the success are the absence of pain, mobility, radiographic lucency (greater than 1.5 mm) around implants, the lack of suppuration or bleeding in the soft tissues, adequate function, and aesthetics in the prosthetic.

The good news is that about 95% of implants today are successful. Moreover, a well-integrated implant with appropriate biomechanical loads can have long-term success rates for the fixture and close to 15 years lifespan for the prosthetic teeth.


References

American Academy of Implant Dentistry:

American Academy of Implant Dentistry:

American Academy of Periodontology:

WebMD:

Wikipedia: --

American Dental Association:

Dear Doctor, A Patient Education Company:

The National Center for Biotechnology Information:

Your Dentistry Guide:

Carefree Dental:


Last review and update: May 2018



Latest

Dental implants, the complete patient's guide

Today, dental implants are the state-of-the-art tooth replacement systems and are now more common than ever before. This comprehensive guide deals with all the important aspects of implant dentistry ...more

Are Gum Diseases and Cancer Linked?

Over years, numerous studies have shown that the bacteria responsible for causing gum diseases might also be able to cause certain types of cancer. Read to learn more ...more

How to sustainin fresh breath with braces

When you wear braces, it is not enough to brush your teeth religiously as you may still suffer from bad breath. These 7 tips will help you while wearing braces and will continue benefiting you after your braces come off ...more