Long Axis of the tooth

Discussion in 'Dental' started by Disneyy, Mar 12, 2018.

  1. Disneyy

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    I'm in my first year and while I'd say i've gotten a decent hang of drilling, I always end up with either my buccal or lingual walls being perfectly convergent and the other being divergent or just straight (usually straight). It depends on the quadrant that i'm working on whether it's my buccal or lingual that's not convergent but always one of them isn't. I've talked to my prof about it and i've been told that the reason is due to not angling my bur towards the long axis of the tooth.

    I have drilled probably hundreds of preps and in my eyes, it seems as though i am drilling towards the long axis, but every single time, I am still left with one of my walls not being convergent.

    To drill, i usually use the 330 on high speed for my initial outline, then i'll take my 245 on slow and refine everything.

    Does anyone have any tips on angling your bur towards the long axis of the tooth/finding the correct long axis of the tooth?
     
    Incis0r likes this.
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  3. frozenicecreamDMD

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    I think you are overthinking this a little bit. in typodont tooth, the axis of tooth isnt easily located and it is a clinical term the professors usually use because they have been used to it in clinic already. However, there is one thing very easily located on typodont tooth is the occlusal plane.

    before drilling, check out a flexible plastic ruler or boley gauge, hold it in one non dominant hand and put it on the tooth you are about to drill (so the surface of the ruler touches lingual and buccal cusps of that tooth), then drill that tooth while making sure the flat end of your hand piece (the circular flat that u press to remove the bur is perfectly parallel to the plastic ruler. this step is done to make sure you are angling the bur perpendicular to the occlusal plane. during drilling, DO NOT look at the bur and keep comparing if you are angling correct or not. your eyes are playing tricks on you. just drill while making sure flat end of handpiece is parallel to the flat end of the plastic ruler (this means the bur is perpendicular to the occlusal plane). Then, tilt it a bit buccal/lingual to make it a bit convergent. this is where the big picture matters. look at it from the whole as long as you keep it relatively parallel it will turn out good. do not drill a bit, then stop, then check, then drill. it is a waste of time and effort and energy.

    applying this technique will make sure you do not need to think during drilling and have 2 perfectly convergent walls no matter what sides you are doing it in.

    as time goes on, your brain will basically build an image of the ruler and align the end of the hand piece to it and you will be a boss at controlling the handpiece and drilling will be a hobby not a pain in the butt.

    Credit: someone on SDN told me this before while i was having the exact same problem as you.

    and last but not least, good luck. the technique i showed you will be applicable to crown preps, class II, on lays, inlays, etc etc every single thing. in sim lab, remember to angle your bur perpendicular to occlusal plane since all teeth are straight, in real life thats where the tooth axis comes in to play.
     
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  4. Incis0r

    Incis0r I LOVE Dental School
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    Great advice. Have been trying to find a fix to this issue too. Will try in sim clinic tomorrow. Thank you!
     
  5. Saddleshoes

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    Can we use the word(s) Cutting, Cut, or To Cut?
    "Drilling", "Drill" and "To Drill" are words used in in the oil exploration industry and unsettling to patients.
     
  6. frozenicecreamDMD

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    fortunately, Dexter the sim mannequin will not possibly find this unsettling.
     
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  7. Flemish

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    Personally I just run through it with a 330D on slow if I need anymore convergence/divergence. A pear-shaped 330 should be giving you convergence on its own anyway.
     
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  8. Disneyy

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    Thank you so much for this!! I will try this tomorrow!
     

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