With the ProTaper® Universal system, as with any instrument system,
a good outcome begins with good access.
We've edited the procedure to focus on just the key points of the technique.
In this clinical example of a lower molar, we'll be focusing on the mesial lingual canal.
All of the other canals are prepared in the same manner.
Once a straight line access has been established,
thoroughly irrigate and lubricate the space.
This is recommended after every rotary file.
Begin with a number 10 hand file.
It doesn't take long to scout the canal space.
This is worked to about two-thirds of the estimated depth of the canal.
Based on the anatomy, the next hand file is pre-curved.
This number 15 file is worked gently to create a glide path for the rotary instruments.
It goes to about the same depth.
Coronal shaping begins with the S1.
This is used at 300 rpm and can be worked in a brushing manner
to move the access away from the furcation.
The S1 is taken no further than the depth of the 10 and 15 hand files
we worked with earlier.
It may take more than one pass to get to that depth.
Shaping file 2 is next.
It goes to the same depth as the S1.
While it may not always be necessary,
the S2 can also be used in a brushing fashion.
Here it goes easily to the predetermined limit.
Throughout the procedure, use of sodium hypochlorite
and a lubricant such as ProLube® is strongly suggested.
These help by digesting tissue and clear the way for files
as they work their way down the canal space.
After the initial coronal shaping, the number 10 hand file is reintroduced.
The 10 is negotiated to the estimated working length
and gets to length quite easily here.
Because of the coronal shaping done with the earlier instruments,
this hand file will normally engage in only the last few millimeters of the space.
The number 15 hand file is then allowed to follow.
These instruments create enough of a glide path
to allow the ProTaper Universal instruments
to comfortably shape the apical portion of the canal.
S1 is reintroduced and is easily taken to length.
Once it reaches working length, remove it.
The S2 easily follows to length
and the canal has a nice tapered shape throughout.
Always remove, clean, and inspect every rotary instrument
frequently throughout the procedure.
Only the final apical size is still to be determined.
It is often appropriate to reconfirm length determinations
after principle shaping is complete.
This is important because removal of obstructions in the canal
will actually shorten the distance between the coronal orifice and the apex.
Finishing file number one is taken to length.
This instrument has a 20 tip and decreasing tapers.
It will provide deep shape
but do almost no work in the coronal portion of the tooth.
Apical gauging with hand files is suggested
to determine a final apical shape.
In this canal, the 20 hand file fits appropriately.
Although we're happy with the fit of the 20,
for this example we tried the 25 hand file.
It is also gently worked into the canal space.
In this specific canal, it is too large and does not quite reach length.
We also tried the 30 hand file.
It is also placed in the canal and, as expected,
based on the previous hand files,
it takes more effort to get close to the working length.
Therefore, the clinical decision for this particular canal
is to leave the preparation at a 20.
To show canal variations, let's take a look at the gauging procedure
of the distal canal of this same tooth.
This canal followed the same instrumentation procedure as the others.
The 20 is loose.
The 25 is also loose at length.
The 30 hand file will make it, but it is tight.
The clinical decision is to use finishing file number three for apical shape here.
The F3 is taken to length and removed
and the canals shaping is complete.