Evaluating the suitablitly of the patient's jaw for an implant. -

What the dentist looks for. / Types of bone deficiencies.

A primary factor in providing for the long-term success of a dental implant is the bone in which it's placed. And because of this, the treating dentist will need to examine the patient's jaw so to determine that the quantity and quality of bone in the region of the planned implant is adequate.

They'll also need to insure that the location for the implant is distant enough from neighboring anatomical structures and the bone tissue is pathology free.

The dentist's evaluation will need to be twofold.

  • One aspect will involve routine examination techniques: Visualization, palpation (touching, feeling), and measuring the jawbones.
  • The other will involve the use of dental x-rays.

What type of x-rays will be needed?

A panoramic dental x-ray.

In many cases, a combination of a panoramic film (a single x-ray that shows both of the patient's jaw bones and all of their teeth) and a few periapical radiographs (the small individual x-rays most often taken in dental offices) will be satisfactory for a patient's examination.

In other cases however, the dentist may feel that the 3-D imaging of a CT scan ("computed tomography", CAT scan) is required. This type of imaging provides substantially more information about the precise relationship between the objects and landmarks being examined.


A dental implant requires an adequate amount of bone.

Factors the dentist must evaluate -

1) Jawbone quantity and quality.

The dentist must determine that there's an adequate quantity of bone in the region of the planned implant and that it's of sufficient quality.

  • Making this determination will involve evaluating the shape of the bone (both width and height).
  • It will also involve evaluating the bone's density. The dentist can get a hint of this from the x-rays and CT scans that have been taken.

2) Reasons why a patient's jaws may be unsuitable for implants.

There can be situations where the dentist will find that the bone in the region of the planned implant is not adequate.

a) Naturally occurring deficiencies.

The bone problem can be naturally occurring, such as resorption (bone loss) that takes place in regions where teeth have been extracted. This type of defect is most common in cases where multiple teeth were removed several years previously.

The magnitude of post-extraction bone loss can be as much as 40 to 60 percent within the first three years after a tooth has been removed. Beyond that point, the rate of loss usually slows down substantially.

The cause of the resorption is typically attributed to disuse atrophy (decreased blood supply, localized inflammation and/or unfavorable pressure from a dental appliance, such as a partial or full denture).

b) Bone damage due to disease.

In other cases, a patient's bone deficiency may be attributed to a dental condition, such as bone loss caused by advanced periodontal disease (gum disease).

As a result of this condition, significant amounts of bone may be lost from around the person's teeth,
to the point where if they are extracted there may be an inadequate quantity of bone in which to place an implant.

c) Previous surgery.

In some cases, the bone deficiency may be due to a previous surgical procedure such as a difficult tooth extraction or the removal of a cyst or tumor.

d) Bone pathology.

The dentist must search for evidence of pathology within the jawbone (including tumors and cysts).

Additionally, impacted teeth and tooth root fragments (remnants of past extractions) need to be identified and removed as the dentist feels it's needed.

A dental implant cannot be placed in the area of the mandibular nerve.

e) Anatomical considerations.

The location of anatomical structures, such as sinuses, nerves, blood vessels and the roots of adjacent teeth must be identified.

This is important because implants must be placed so they are suitably distant from these objects.


Bone grafting may be necessary before an implant can be placed.

A dental implant cannot be placed in the area of the maxillary sinus.

Bone grafting will be needed.

Since the success of a dental implant will be greatly dependent upon the bone in which it's placed, the treating dentist may feel that it's necessary for them to perform bone grafting so an adequate amount exists.

This is typically a separate procedure that must be performed (and allowed to heal) prior to placing the implant.

We discuss one such grafting procedure termed a Sinus Lift. It's frequently performed in association with placing implants that replace upper back teeth.


Evaluating the patient's soft tissues.

A portion of the dentist's clinical examination must also involve an evaluation of the soft tissues of the patient's mouth. Of course, they must find that these tissues are free of pathology and appear to be healthy.

They must also evaluate both the quantity and type of tissue that exists in the immediate area around the implant site. The right type of gum tissue (attached gingiva, gums tightly bound to the bone underneath them) must surround the implant to insure its long-term success.

 

 

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