The tooth implant procedure. - Part 2
Part one of our overview of the dental implant procedure begins here. (To jump to a specific topic, use one of the blue tabs to the right.)
Step 7 - Drilling the hole for the implant.
Once the pilot hole has been completed, the dentist will continue the drilling process using a set of bits, each of which has a slightly larger diameter.
As each one is used in turn, the hole will be gradually enlarged, until it is the correct size for the implant that has been selected.
What size implant will be placed?
The length and diameter of the implant that's chosen will depend on the amount of bone that's present at the implant site.
Larger has advantages.
In general, the dentist will want to use as large a tooth implant as is reasonably possible. This is because longer and larger diameter implants distribute their load to the surrounding bone more favorably than comparative smaller ones.
Most dental implants that are placed are on the order of 4mm in diameter (around 3/16ths of an inch).
Some dentists consider a diameter of 3.25mm to be the smallest that can insure adequate implant strength.
Tooth implants greater than 4mm are available but they're not widely used because sufficient bone width for them is not often available.
Step 8 - Double checking the implant's hole.
Step 9 - The dentist will thread the hole.
The dentist will now need to use a thread-forming tool (a screw tap) to create threads in the bone that match those found on the implant.
Treatment variation - Self-tapping implants.
Some types of dental implants have a self-tapping feature.
As they're screwed into place, their cutting edge creates the grooves needed for the implant's threads. No separate thread-tapping step is required.
Step 10 - The dentist will place the implant.
Now that the hole has been properly shaped, the dentist can go ahead and insert the dental implant in the jawbone.
Step 11 - Closing the surgical site.
a) Placing the implant cap.
At this point, the dentist will screw a "healing" cap onto the exposed portion of the dental implant so its internal aspects are sealed off from the oral environment.
b) Placing stitches.
They will then trim and shape the two flaps of gum tissue and reposition them back over the patient's jawbone and around the dental implant. They will place a few sutures (stitches) to hold the gum tissue in place.
c) Healing times.
The stitches are usually left in place for about seven days. After this time period the gum tissue will have healed sufficiently that they can be removed (a very painless procedure).
Usually, the implant is given a period of three to six months to osseointegrate (fuse) with the patient's jawbone before it is restored (Step 13). This will, however, vary on a case-by-case basis (see below).
d) Some implant protocols require two separate surgeries.
In some cases, a patient's implant procedure will require two separate surgical procedures.
The first surgery.
The initial surgery involves the placement of the dental implant itself as we have just described, with the exception that the gum tissue flaps are positioned back in a fashion where they completely cover over both the jawbone and the dental implant.
The second surgery.
A very minor procedure is then performed after the healing (osseointegration) of the dental implant has taken place. The purpose of this surgery is to trim back the gum tissue so the implant's healing cap is exposed (so it can later be removed and a final dental restoration placed).
Step 12 - Surgical site healing. / Implant osseointegration.
How much healing time must be allowed?
A dentist will typically wait three to six months before starting the process of making the implant's final restoration (a crown, bridge or denture). During this time frame the osseointegration (fusion) of the dental implant with its surrounding bone tissue will take place.
(In some cases a dentist may be able to place some type of "tooth" restoration on the implant the same day it is placed, see below.)
This timing can vary.
When making a determination about the needed healing time frame, the dentist will take into consideration the type of bone in which the implant has been placed (both bone quality and quantity), the implant's size, and other factors such as the type of surface treatment the implant may have received during its manufacturing process.
Why is a wait period needed?
The reason that a waiting period is usually required is based on the following.
If the implant is placed under a load while its healing process is taking place, any resulting implant movement can cause the formation of a fibrous tissue encapsulation of the implant rather than a true state of osseointegration (implant-to-bone fusion).
Placement of a temporary restoration may be possible.
Your dentist may be able to place a temporary restoration on your implant when it is initially placed (before the osseointegration process has occurred). The esthetic and functional advantages of this option are obvious.
For this scenario to be possible, the implant must have good primary stability (is anchored firmly in the bone at the time it is initially placed).
Additionally, the temporary dental restoration needs to be designed where the level of chewing forces it transfers to the implant are not be greater than what its primary stability can withstand (so no implant movement takes place).
Step 12 - Placing the implant's permanent dental prosthesis.
Once an adequate healing period has elapsed, the implant can have its final dental restoration fabricated and placed. This might be a dental crown, bridge or denture.
In preparation for this procedure, the dentist must remove the healing cap that was screwed onto the implant at the time of placement and replace it with an appropriately shaped abutment. This abutment portion of the implant provides the nub to which its final dental restoration can be secured.
Our animation above shows x-rays of this process.
- Stage #1 - The implant has osseointegrated and is ready to be restored.
- Stage #2 - The implant's abutment has been screwed into place.
- Stage #3 - A dental crown has been fabricated and cemented over the abutment. This patient's treatment is now complete.