endo sheet # 7- Leen Kutachi

Endo lec.7
Date:31-10-2010

Instruments for access cavity preparation

Basic instruments pack;
1.front surface mirror
2.endodontic locking tweezer
3.DG16 endodontic explorer the last one in the h.out pic.after acess cavity the orifices should be identified by the head of it.
4.violet prope.
5.long shank excavator inorder to remove the content of the pulp chamber.
6.surgical hemostat.
7.mm ruler to do our measurements which is the working length.
8.amalgum plugger
9.flat plastic instrument (it doesn’t mean that it is plastic it is a metal instrument but used for plastic restorations(amalgam and composite))
10. different types of burs high and low speed
You should know that access cavity is a 2 stage procedure the first procedure is done by the aid of high speed hanh piece (penetration into the pulp)
2nd stage is done by low speed bur round or fissure
s.times we need the extra long bur to reach the pulpal floor to do the unroofing of the pulp chamber.
s.times the safe ended bur(d in the h.out pic)is v.useful so not to damage the floor of the pulp chamber specially in premolars and molar teeth.
Gates glidden bur to
1. prepare the coronal 2 third of molar teeth.
2. to remove the gotta percha (which is the filling of the root canal)
3. for retrieval of broken instruments inside the canal.
Properties of gates glidden burs:as you can see in the h.out it has 1,2,3,4,5,6 dash bands so the size differ accordingly. these burs are either with short or long or v.long shaft depending on the depth of the canal.
And the head size differs according to the dashes mentioned.
These gates glidden burs are very fragile and should be used v. carefully they should be used passively inside the canal bcs these burs will not follow the shape of the canal ,so they are used in the coronal two-thirds of the canal passively with a brushing action upwards.

Endo Z burs they have non-cutting tiphigh and low speed ,they are useful in access cavities of premolars and molar teeth to make smooth and diverge walls towards the occlusal surface..then walls should not have any undercuts.why?
Not bcs of enamel rods direction
1.visibility would be better
2. to provide a resistance form to the temporary restorationso so not to be disloged under occlusal forces bcs if it dislodge the coronal seal would be broken then recontamination with infection between the visits will occur)

Note:
.in end we make diverge walls opposite to conservative which is converge.
.in endo treatment we need more than one visit

***criteria of orifices in molar teeth:the location of the orifices should be completely on the floor of the pulp chamber btwn the junction of axial floor and pulpal floor and at the line angle they should not have Mouse Hole Effect(the dr. said check what is it from previos years slides)

Rubber dam: you should never ever do endo without it ,it should be always applied .so it is mandatory because it
-protect the patient from ehalation or ingestion of instrument ,medicaments and debris .
-it will provide clean dry field of operation .free from salivary contamination.
-it will prevent the tongue and cheeks from obstruction the operation field.
-prevents the patient from raising the tongue and so disturb the efficiency of the treatment.
Rubber dam is a must and if we cannot put them the whole treatment should be questioned,so if the tooth was v.badly destructed and we cannot put a rubber dam we should build up the tooth,gingival surgeyy, crown then we apply it.
It has several parts:
1.rubber sheet with different thicknesses(thin medium and heavy) and colors(purple,green)
2. plastic frame of 2 types:metal and plastic ,although both can be sterilized and both are nit disposable ,but the plastic one is better bcs it will not show durind taking X-ray while the metal interfere.we usually take multiple x rays preoperative ,working length radiograph ,sorry it is not clear,and post operative radiograph.
3.puncher :makes the holes inside the rubber bam.
4.foreceps which carry the clamp to the teeth needs isolation.
5.clamps:different types of them depending on the shape and position of the tooth inside the jaw, wether ant.,post.,molar,premolar…
In the pic it shows multiple isolation(more than one teeth are being isolated)this is not common ,the single tooth isolation is more common where we isolate only the tooth we want to treat it.
Eg.14,14a are good for molar teeth
Clamp in pic 1 is good for premolar tooth.

There are 2 types of clamps:

1.with wings like 14
2.wingless like W8a
The one with wings is more common and it gives a better isolation bcs it goes under the sheet so prevents contamination with saliva .

Endodontic field is developing quickly ,every year new instruments are developed to increase the efficiency.


Instruments 4 root canal preparation:

1.hand operating inst.
2.enginrapid ins.
3.ultrasonic and sonic ins.

We have to understand the physics of root canal inst. Inorder to facilitate the most efficient use of the inst.,minimize the time for breakage or fracture,allow the clinicine to achieve the treatment ideas ,choose and use current and future inst. To the greatest effect,provide financial reward bcs inst. Of endo treatment are expensive,,safe time,and enhance the quality of the treatment.
There are large no. of root canal inst. Available,they are manufactured from different alloys ,cross sectional shapes and diameters.
-carbon steel…………..disadvantage brittle.
-stainless steel………..more resistance
-flexible stainless steel………most used before
-nickel titanium files…………now they r used very widely manually or in engine drill

Cross section of files:
Square ,triangular,rhomboid,circular or Scurved.

-square………rigid,least flexible,usually small in size.
-triangle……..more flexible,they r larger
-rhomboid………most flexible,favourable and best

Note:Every canal is curved unless proven otherwise.
Note:the less u alter the shape of the canal the better the prognosis,so u shape the canal without changing the whole shape of the canal,so if it was curved ,u make it wider without changing the curve.

Files can be made by twisting the flank of the metal,or by machining.
Files are used for shaping.
The more the twisting the more the cutting edges.

Files and Reamers
-up to size 40 the cross section of the files or reamers is SQUARE,it suppose to be rigid bcs it is square but it is not that rigid bcs its small.
-45-140 the cross section of file and reameris TRIANGLE to add flexibility

The 2nd type of files are the flexible stainless steel which can be either flexofiles or flexoreamer
Always in flexofiles the cross section is triangle, to increase flexibility.
Rubber stopper,moves according to the working length(root length)see it in the slides

DIFFERENCE btwn files and reamers:

File…………more twisting,cutting edges r more than reamers,forms acute angle with long axis of the file

Reamer…………less twisting,cutting edges r less,parallel to the long axis ,make helix angle.

These will affect the mode of playing with these inst.eg..the file will cut with filing action while reamers by rotation (helix angle)

COLOR CODING in endo means the sizes of the inst. ,every color means a size.(easier)

Yellow…file, the size means the size of the tip of the inst. So if it was 20 then it is 0.2 of mm

Green….flexofiles or flexoreamers,more flexible,size 35 means that the tip is 0.35 of mm

Red….size 25 this is different than the others it looks like inverted cones it cant be produced by twisting it is produced by machining,cutting edges like right angle to the long axis of the file,most efficient way to use it by pull action ,cross section is like a circle,symbol is circle.
Purple 10(tip diameter is 0.1mm),grey…green…black at first increase in size of tip diameter is 0.05 then it becomes 0.1 btwn 60,70,80.

(the colors and no. r all to be memorized from the h.out )



All the inst. Should be standardized by ANI(American national institute),ISO(international organization)
Standardization of 1.size 2.taper 3.length of cutting blade 4.cutting tip

k-reamer …………the k is for kerr (the name of the company)the symbol that is drawn on the inst. Is not the cross sectional shape it tells u that this is a reamer(if it was triangle).
Symbols:
-triangle……reamer
-square………file
-circle…………H-files (headstrone file)

Dzero….tip diameter ,the angle is 75
D16…..16 ml away from dzero is the diameter d16,no angle here,and this is what we usually use.
Whenever we go up twe get a cone shape(taper) and the diameter increases,conical in shape as the shape of the canal .(largest diameter in orifice,smaller in minor constriction)

Taper of the inst, is also standardized which is called 02TAPER means that the inst. Diameter increases by 0.02 mm with each 1mm from the inst. Tip.
D-16 02taper is 0.32 and if we start from 10 in d 16 then it is 0.42

According to the root canal length ,it might be long,medium,shorteg..in canine differs than lower incisor BUT the cutting segment is always 16
Canine….31 or 28
Molars….21 accesibility to tooth is limited if longer.gates glliden follows the same thing here (standardized)if 1 dash …5mm, 2 dashes +20….(actually I didn’t understand this check it plz)


Piped barbar(check the name from h.out):it is used to take the pulpal tissue in 360 degree(??)not to be used in narrow canals bcs its spikes are very fragile so it might break inside.
k-flex files are rhomboid in cross section which is very flexible,used in rotational action and filing action.(but reamers is to be used only in reeming action and not in filing action)

flexo files are triangular in cs stainless steal alloy with a non cutting edge.
If the canal was small it is better to enter it with acutting tip file,but if wide we use a non cutting edge file bcs cutting edges might make ledges and changes in the way.

Flexo R file (rone) called Rone technique,used with a balance force technique durinr preparation.

Golden medium files using files of 10,15,20,25,30,35..might cause a problem bcs when we jump from size10-15 it is only one size difference ,but if u count it as a percentage it is 50% of increase in the tip diameter so that’s why they invented golden medium files 12.17.23.32,37.



The tip of the file might breaks if it reaches the tortional limit(the amount of rotational torque that can be applied to a tip of inst.to the point of separation,fracture and failure)
Inorder to avoid the inst. Fracture u have to notice if there is any change in the file ,,if there was:-
-unwinding of the flutes (twisting clockwise and opening of the flutes.
-roll up of the flutes which is excesiveclockwise twisting after unwinding
-corrosion
You have to throw it directly.

Nichel titanium files: super elastic 55%nichel,50%titanium, ideal for curved canals but it cannot be precurved .
Manual NTF IT HAS A DISADVANTAGE THAT ITS CUTTING IS LESS THAN STAINLESS STEEL.
But now we use rotatory NTF which is excellent, it has different kinds and shapes using a special kind hand piece which has a speed of 250-300rpm
It is preprogrammed so we use files without fracture,there are 30-40 systems the system that the dr. use is theProtaper system it has files which differ than manual files; (akit with 6 files)
3……….for shaping ,variable taper (not constant)and big
3………for finishing ,fixed in last 3mm then decreases(taper)


Every thing here differs than the mechanical files color coding,tapering(variable tapering)


Ultrasonic and sonic for quick irrigation during root canal treatment.

We have measuring devices like rulers.

STERILIZATION
Either by pressure steam (we have to know the temp/ h.out) dry heat ,pressure steam autoclave.
Beed(??? Not clear)sterilization has certain kinds of salts used in sterilizing small inst. During our work with the same patient,but not safe from patient to another.
Clinical disinfectant

The most recent invensions in endo treatment are the:
-electronic apex localizer(will be discussed the next lec.)
-endodontic microscope.


ALL the sizes and color coding numbers are important and to be memorized from the hand out



Corrections are welcomed ,good luck
Done by : Leen Kutachi