RCT question for future or current dentists (endodontists)

[DentPursuer88]

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Hey guys and gals,
I was wondering if you can give me some advice about the steps consisted in a root canal treatment.

I've been collecting extracted teeth for about 5 months and decided to do a RCT for kicks lol. I worked on both number 15 and 19 recently.

Now at first a created a straight line access. Once that was done and I reached the pulp cavity, I started looking for the canals. On #15 I found canals mb1, db, p and that was it. I was hoping to find a mb2 but I guess (from what I was reading) that occurs mostly on maxillary 1st molars. On #19 I found Mb, Db, Ml, Dl. This is where I am going to need your advice.

I am doing a traditional root canal (not using rotary or apex locators). So I was wondering what you guys would do to start tapering the canals. What I did was (1) locate the canals then used a size 08 file and started going up until I hit 45. (08-10-15-20-25-30-35-40-45). What should the expected or should I say preferred canal look like and how would I get it to look that way? Also to open up the orifice of the canals, would you guys use a Gates Glidden or like an 04 or 06 k-file? All the advice would be greatly appreciated. Sorry if I wrote too much.

Oh and by the way. If you wanted to measure the length of the canals using a diagnostic PA, would you fill the gutta percha all the way to the tip or go short of it just a little. (example: MB and DB measure 20 mm. when I put in the gutta percha with the sealer should i go down to a 19mm or should i just stay the same?) just curious guys. thank you all.

 

[Midoc]

You're doing well to think about these things but you have a few ideas out of order.

Straight line access (SLA) is acheived after you access the pulp chamber. You can put a small diameter file partially down the canal, if it bends in the upper portion then you don't have straight line access.

MB1/2 is all based on statistics. If you're doing 3/14 then you should spend at least five minutes looking for it. 2/15 less than five minutes.

Your final apical diameter is going to be based on feeling eventually but before that you need to remember what the canals look like before you touch them. On an upper molar, the MB and DB canals will be smaller than the P canal. On a 20-30 year old, expect .30-.35 MB/DB canals, .40/.55 P canals.

To open up the oriface of canals, the Gates-Glidden is an excellent instrument. It is both cheap and reuseable. But know well that it is designed ONLY to open the apical 1/3 of the canal. DO NOT GO BEYOND THIS or you have great potential to ledge or perforate the canal. Also, DO NOT FORCE THE GATES-GLIDDEN or you have great potential to ledge/perforate the canal.

The theory behind the diagnostic PA and being 0.5mm short of the radiographic PA is that the actual orifice constriction is generally 0.5mm short of the radiographic PA. If you're not sure what I'm talking about then you need to hit the books. Your goal during an endo is to be neither short of the actual apex nor long of the actual apex.

 

[DentPursuer88]

Thank you Doc. for your great advice. I apologize if I misunderstood any of the concepts, I am probably way ahead of my self, but I figured I would get the fundamentals down (you think i'm starting too early lol =19 yrs. old)

Okay, so from what you just wrote, you are saying that you can get the SLA until you access the pulp chamber. Would you use an Endo Z? Also what type of bur do you use for the access? Round bur? Basically if done correctly, there shouldn't be any pressure on the upper portion of the file, correct?

I understand what your saying about the MB1/2 for 3/14 and MB1/2 for 2/15. However, when looking for MB2, where should i look? More distal to MB1 in between the MB1 and P canals?

I did notice that the P canal was extremely large compared to the MB and DB canals.

So my question to you is, once your done measuring the length of the canals, what size Gutta percha do you put in after you irrigate with NaOCl (ex. MB=20mm DB=19mm P=25mm, and i ended up finishing with MB=.35 hand file for tapering DB =.35 P= .45) I am guessing it depends on the size of the orifice that I created? Like if I used a Gates Glidden for 1/3 of the canal, would that be like a .04 or .06 rotary file?) SORRY FOR THE CONFUSION HERE, I HAVE A LOT OF WORK TO DO lol.

FINALLY, when you irrigate the canals, do you use NaOCl or Chlorihexidine or both. And how can you avoid the extrusion of the NaOCl through the apical foramen? Do you put the syringe all the way to the apex or midway or do you let it float?

Once again I apologize for all the confusion, I really appreciate that help that your giving me.

BTW, I know what you meant about the PAs. Thank you.

 

[dheav005]

geez, man. at 19, straight line access wasnt exactly on the top of my list of things to achieve. shoot, it didnt even make the list.

to build off of my fellow dental officer, round burs are a great choice for access. usually, ill use a 4 or 6 round for premolar/molar access. the nice feature of an Endo Z bur is the non-cutting tip, which can be places over the orifice and then 'leaned' out against the axial walls to provide SLA down each canal. the goal is for my patency file to drop through the (usually) straight coronal third to the inital point of curvature. without adequate access, taking working length and master apical file radiographs becomes a nightmare of crowded files poking througha small hole.

MB2 should be along the developmental line (pulp map) between MB1 and P. it will be smaller than any of the other orifices, even hidden under a spur of dentinal wall. always assume two canals are present until examination proves otherwise.

your master apical cone should match your master apical file in the apical third. while this is mostly true, if you have any binding coronally, you will be hard pressed to match the file and the cone. while a 35/02 file is a standard, a 35/02 cone can vary from a 30 to a 40 tip. brasseler has a file system that seems to have really accurate matches between MAF and MAC, but you have to crawl before you can walk. so, flare the canal coronally with your GG drills (#2,3,4) to minimize the binding higher up in the canal, then fill that space with accessory cones.

NaOCl is my standard irrigation, though i have used various combinations of CHX, EDTA, citric acid and doxycycline (MTAD BioPure) plus lubricant like RC Prep. it depends on the state of the tooth when i get the patient in my chair. infection, pulpitis, carious exposure, retreat? all play a role in determining my irrigation approach. i use side vent needles on my irrigation syringe which i bend 2-3mm short of my working length, providing a physical stop while assuring i get my chemical debridement as far down into the root canal system as possible.

 

[OceanDMD]

Go to dentaltown and check out the endo threads(especially a guy named Ragnar). I think the access preparation is the most important step. You should be able to look straight into the access and see all of the orifices (straight line access). Any preparation beyond this is excessive. As far as instrumention goes, learn rotary. I use protaper. Always open and prepare the coronal/middle third of the canal before trying to work the apex. Lots of irrigation and recapitulation. If you work too early on the apex, more ledging, blocking of the apex, and instrument separation is likely. Loupes are crucial, and the microscope is likely the next piece of equipment that will be considered standard of care.

Bottom line, go check out dentaltown's endo threads. You will be blown away. I routinely find 4, 5, and sometimes 6 canals in my 1st molar cases now. You really need to pick and choose your cases. Good luck, molar endo is one of the most valuable skills to learn especially early in your general practice career.

 

[DentPursuer88]

thanks ocean & dheav, I am learning a lot from these posts.

I am actually going to check dental town and see what they say. Looks like I could learn a lot there also. I will keep you guys up to date with my progress. Thank you for the support.

If you have any more advice please feel free to add 😀