Sunday, April 9, 2017

DIY Oxygen Gel

DIY Liquid Strip. When resin cementing, you need to do the final cure with glycerin gel to block air and prevent the oxygen inhibited layer from forming. It's essential for resin bonded porcelain restorations such as veneers and crown-lays. If you're a Cerec or e4D user, you probably go through lots of this gel. My recipe has three ingredients: glycerin gel, a 3cc syringe, and 18 gauge flowable tips.

Walmart brand personal lubricant, water based (aka generic KY jelly) is primarily glycerin.  Easiest way to get it in manageable quantities.  At $2 for 4 oz, it will last you for dozens of restorations.  Thanks to Greg in Long Beach for this tip, though he prefer's Walgreens brand. If you want to get glycerin by the quarts or gallons, it's available on Amazon for even less per ounce.   I suppose you could mix your own Dentatec milling solution with glycerin and some other ingredients, but I don't have a recipe for that on hand.

Fill a 3 or 5 cc luer lock syringe with the gel.   Shop for 3 cc syringes on Amazon or eBay.  Aim for 10 cents per syringe or less. You can also get them at your dental supply dealer.  I like the Vista brand 3 cc syringe.  As of this writing, it was $10.69 for 100, very competitive with Amazon and ebay, with a freegoods promo on top of that.  You can go with larger syringes if you like; that's just what we had on hand.  3 to 6cc seem to be small enough to maneuver easily.  1cc gets refilled too often, 12cc starts getting clunky.

Use large 18 gauge pre-bent tips.  We use these ones from smartpractice, but any fat flowable tip will do.  You can also find 18 gauge pre bent syringe tips on eBay or Amazon.   eBay seems to be best of small ticket disposables; Amazon's prime and fast shipping comes at a cost that's hard to absorb for low priced items.  As a side note, I prefer 18 gauge for glycerin gel and Parkell Dryz, 20 gauge for thicker flowables like Clearfil Majesty flowable (the biomemetic favorite, I'm told), and 25 gauge for thicker etches like Kerr, Ultradent, or my recent favorite, Etch royale from Pulpdent.

Resin Cement Curing tips:

Prime your tooth and your restoration as directed.  Every system is different, so read the instructions.  Generally, you'll want to acid etch the restoration and prime it.  We like Ivoclar Etch and Prime because it's relatively safe compared to hydrofluoric acid, and it adds a primer in the same step.  Etch and prime the tooth, following the directions for your cement system.  Do your tack cure, usually 5 seconds, then clean off the excess cement thoroughly.  Err on the side of undercuring the cement...and beware of curing light overlap.  I tack 5 seconds at each corner, so the overlaps are at the mid buccal and the mid lingual, which are easy to clear if the cement over hardens.  Floss with a knot in it is very useful for cleaning out the interproximals.  After the tack cured cement is cleared, apply the glycerin gel liberally.  You want to be generous with this stuff, so that you'll block all the oxygen out for the final cure.  Any spot you miss won't cure at the surface.  Today's omission will be tomorrow's stained margin or even open margin.  The cement will just wash away within a week.  Ask me how I know.  Once the tooth is thoroughly covered in gel, cure every margin thoroughly.

Sunday, April 2, 2017

Review: SeaSky Mini Handpiece

I've just tried these mini head handpieces for a few weeks. My early impressions are very good.

  • Very small head.  Not quite as small as a Pico Max, but less than half the size any of the bargain high speeds on ebay.  Easily small enough for pedo. Visibility is accordingly superb.
  • Very bright fiber optic.  My LED couplers shine quite brightly through it.  Pretty slick considering how small it is.
  • Decent Torque.  I've done a few crown preps with it.  There's no replacement for displacement, so it won't be your favorite.  But for limited access and/or pedo, you'll like this.
  • Very light weight.
  • Very good textured grip.  I LOVE LOVE LOVE the powder coat finish.   Why can't all handpieces have this?
  • Loud - it has a very loud, high pitched whine. Very pure tone, and that's a bad want the frequencies spread out. A lot of Chinese handpieces do not have very soft o-rings to reduce noise.  The unintentional benefit is less bur wobble and smoother margins.
  • Short shank burs - this is common to small head handpieces.  Start a collection of short shank burs (I often just cut a few down with a 556), because regular shank burs stick out awkwardly from this handpiece. 
  • Coupler not included - you'll need a kavo multiflex coupler, or one of the many compatible ones.  

Shop on eBay for the SeaSky Mini LED on Kavo Multiflex connection here.

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