Topics

What is dental implant?

Composition of an Implant

Anatomy of Implant

Who should perform the Implant placement?

Surgical procedure

Restoration Procedure

 

What is dental implant?

Dental implant is an artificial root of the tooth used in dentistry to support restorations that resemble a tooth or group of teeth.

All dental implants today (21st century) are root-form and they are placed inside the bone (endosseous implant). Prior to the advent of root-form endosseous implants, most implants were either blade endosseous implants, in that the shape of the metal piece placed within the bone resembled a flat blade, or subperiosteal implants, in which a framework was constructed

Implant is used to support a crown (for the case of missing a single tooth) or they can be used to support bridge or denture (for the case of multiple missing teeth) that are designed to look just like your natural teeth.

  • Dental implants are small screws made of pure titanium that are surgically implanted in your jaw.
  • They provide a permanent foundation for crowns, bridges and dentures.
  • They are proven technology backed up by more than 50 years of development.
  • Dental implants protect your jaw against bone loss.
  • Because dental implants anchor in the jawbone just like natural teeth, they are the best choice for natural-looking tooth replacement

 

Composition of an Implant

A typical implant consists of a titanium screw (resembling a tooth root) with a roughened or smooth surface. The majority of dental implants are made out of commercially pure titanium, which is available in 4 grades depending upon the amount of carbon and iron contained. More recently grade 5 titanium has increased in use which offers better tensile strength and fracture resistance.  Implant surfaces may be modified by plasma spraying, anodizing, etching or sandblasting to increase the surface area and the integration potential of the implant.

 

Anatomy of Implant

Implant/Fixture – titanium material for osteo-integration with the surrounding bone.
Abutment – structure which connects the implant to the crown and it is situated in the gum area.
Crown – Usually porcelain fused to metal material that can be seen in the mouth.

What is the difference between dental implant and natural tooth?

 

 

 

 

 

 

Who should perform the Implant placement?

Implant surgery may be performed as an outpatient under general anesthesia, oral conscious sedation, nitrous oxide sedation, intravenous sedation or under local anesthesia by trained and certified clinicians including general dentists, oral & maxillofacial surgeons, prosthodontists, and periodontists.

 

Surgical procedure

 

Surgical planning

Prior to commencement of surgery, careful and detailed planning is required. Two-dimensional radiographs, such as orthopantomographs (OPG) or periapicals radiograph are often taken prior to the surgery. They are used to identify vital structures (such as the inferior alveolar nerve or the sinus), as well as the shape and dimensions of the bone to properly orient the implants for the most predictable outcome. In some instances, a Cone beam tomogram (CBT) or CT scan will also be obtained.

Jaw X-ray — Dental Panaromic Tomogram (or OPG)

Cone Beam Images of the jaw bone

 

Implant placement procedure

In its most basic form the placement of an osseointegrated implant requires a preparation into the bone using either hand osteotomes or precision drills with highly regulated speed to prevent burning or pressure necrosis of the bone. After a variable amount of time to allow the bone to grow on to the surface of the implant (osseointegration) a tooth or teeth can be placed on the implant. The amount of time required to place an implant will vary depending on the experience of the surgeon, quality and quantity of the bone and the difficulty of the individual situation (usually between 30 minutes and 2 hours).

Preparation of recipient bone for implant insertion

Surgical procedure

An incision is made over the crest (highest point of the gum ridge) of the site where the implant is to be placed. The gum (which is referred to as a ‘flap’) was raised  to exposed the recipient bone. Then, a pilot hole is bored into the bone, taking care to avoid the vital structures. Drilling into jawbone usually occurs in several separate steps. 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 bone cells by overheating. A cooling saline or water spray keeps the temperature of the bone to below 47 degrees Celsius.

 

Implant insertion into recipient bone

The implant screw can be self-tapping, and is screwed into place at a precise torque 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). Typically in most implant systems, the osteotomy or drilled hole is about 1mm deeper than the implant being placed, due to the shape of the drill tip. Surgeons must take the added length into consideration when drilling in the vicinity of vital structures.

Before implant insertion

After implant insertion on the upper right area

For Anxiety Patient…

If in a case of an anxious patient come for implant placement, usually, we will prescribe some medication of reduce anxiety before the surgery or patient will have to inhale nitrous oxide during the procedure so that he/she will feel relax and calm all the time during surgery. If the patient is extremely phobia of surgery, then he can opt for surgery done under general anaesthesia which required hospitalization.

 

Healing time

Practitioners usually allow 2–6 months for healing. If the implant is loaded too soon, it is possible that the implant may move which results in failure. The subsequent time to heal, possibly graft and eventually place a new implant may take up to eighteen months. For this reason many are reluctant to push the envelope for healing.

Wound healing – immediate after surgery

Wound healing – 7 days after surgery

One-stage or two-stage surgery?

When an implant is placed with a ‘healing abutment’, which comes through the mucosa (or the gum), it is referred as the one-stage surgery. (Picture above is one-stage surgery where the healing abutment – green and purple screw can be seen on the gum surface)

When an implant is placed with  a ‘cover screw’ which is flush with the surface of the dental implant and usually hidden under with the gum, this surgery is referred as the two-stage surgery. A second surgery is needed 3 months later to exposed the cover screw and the cover-screw is to be placed with healing abutment.

Two-stage surgery is sometimes chosen when a concurrent bone graft is placed or surgery on the mucosa may be required for esthetic reasons. Some implants are one piece so that no healing abutment is required.
In carefully selected cases patients can be implanted and restored in a single surgery, in a procedure labeled as “Immediate Placement“. In such cases a provisional prosthetic tooth or crown is shaped to avoid the force of the bite transferring to the implant while it integrates with the bone.

 

Surgical timing

There are different approaches to place dental implants after tooth extraction. The approaches are:

  • Immediate post-extraction implant placement.
  • Delayed immediate post-extraction implant placement (2 weeks to 3 months after extraction).
  • Late implantation (3 months or more after tooth extraction).

 

Restoration Procedure

 

For missing single tooth

Implants can be made to replace missing tooth or teeth. If an implant is used to replace one missing tooth, it is  implant-supported crown.

Implant-supported crown is used to replaced a missing tooth

 

Multiple missing tooth

Implant-supported crown can be used to replaced multiple missing tooth. Every missing teeth will be replace with implants

Implant-supported crown

If in cases where the bone is too narrow and not suitable for implant placement then implant-supported bridge will be used to avoid those unsuitable area.

Implant supported bridge

Implant-supported bridge also can be used to reduce implant cost and surgical time!!

 

Impression taking

After the implant in well osteo-integrated with the surrounding bone, construction of the outer part — the crown/tooth procedure can be started. Usually it started with impression taking after the gum heals around the healing abutment.

Gum healing after a week with healing abutment in two-stage surgery

Impression is used to make a duplication of the gum and the implant position where the laboratory technician can fabricate crown/bridge outside patient’s mouth.

The impression transfer posts are inserted on the implant fixtures

And impression of the gum and implant are taken with silicone material

 

Crown/Bridge fabrication

In the dental laboratory, porcelain fused to metal crowns or bridges are fabricated. Usually it takes about 2-3weeks to be done.

A model with implant is made from the silicone impression.

On the model, crowns are fabricated and ready to be fit in patient mouth!!

Another case with two implant-supported bridges

 

Restoration of crown/bridge in the mouth

There are basically 2 types of ways by which the crowns/bridges that can be attached to the implant:

Screwed retained – The crowns/bridges are retained in the mouth with screw that screw into the abutment. The advantage of using this way is easy to be removed when ever need (eg. if the crown break or the abutment become loosen). However, the aesthetic will be compromised. Usually screwed retained method is used in posterior region where aesthetic is not an issue or in straight abutment type.

Cemented retained – The crowns/bridges are cemented onto the abutment with cement such as temp-bond, GIC etc. The advantages is very good aesthetic. Usually used in the anterior region or in angle abutment type.

Below are the procedures of installing the final restoration of a screw-retained type:

After removing the healing abutment, the implant ‘hole’ will be assessed
The abutments are screwed into the implants with force 15Ncm

Then, the crowns are fit onto the abutments and the colour, shape and occlusion will be assessed
After that,  crowns will be screw onto the abutments with force of 15Ncm
The hole at the palatal surface will be covered with filling material
Final result!!

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