March 1, 2004
by Janice Goodman, DDS
PORCELAIN VENEER TIPS
Bonded contact points
Here are three very easy solutions to this hassle:
1. Use a Cerisaw (Den-Mat).
2. Place a flat bladed instrument interproximally from the lingual and torque it fairly gently.
3. Leave it bonded! Let the patient leave with it bonded and the contact point will open on it’s own almost every time.
A drop of water on the underside of the veneer is a good idea as the veneer is whiter when it is dry. The drop of water will bring the value down to a shade closer to cemented porcelain. Of course, if you are using try-in cements this is not necessary.
If remaining enamel is not too stained, try making the veneer a half shade lighter than you want to end up with and then using a translucent luting agent and letting the tooth shine through.
White precipitate inside a porcelain veneer
This may be a sign of overetched porcelain and will affect the bond strength. Do not cement a veneer if it has this precipitate inside.
An Essix type appliance (Raintree-Essix) is a reasonable substitution candidate for night-time protection when patients do not opt for a full night guard. It is cheaper, less labour and generally more comfortable than most bite planes.
Here’s a novel idea: since it is a fact that different brands of A2 porcelain look really different when placed side by side, see if you can have your lab fabricate a custom shade guide of shades of the porcelains you most regularly prescribe. Another suggestion is to have a custom shade tab of say A2 of every porcelain that your lab offers, to help you appreciate the different opacities and other characteristics of each one.
Consider ordering shoulder porcelain for the labial cervical collar on PBM crowns. It is a translucent, florescent porcelain and when used with cut back metal will solve the dark margin problem of PBM crowns.
Use translucent porcelain on non-discoloured teeth with clear luting cements, and chromatic porcelains with opacious cements otherwise. You can even dilute saturated porcelains to make them more translucent without weakening them. Den-Mat makes a white-ish translucent cement that’s nice for bleach colours (Ultrabond). Make a point of really understanding the porcelain systems available to you.
Get a commercial set of porcelain polishers for your office and stop sending cases back to the lab after minor adjustments. Most intraoral porcelain polishers recommended to dentists are rubber based, wear out quickly and don’t necessarily do the best job. The silicon based ones that the labs use (try Brasseler), cost about $40.00 each, but last forever. A set of three: blue, pink and grey is usually sufficient to get the desired polish. A final polish with a slurry of porcelain powder and brasso will perfect the shine.
CEMENTING ALL PORCELAIN CROWNS: CAUTION
Popular for cementing crowns, resin reinforced glass ionomer cements are often the best choice as they are highly biocapatable and very retentive. Keep in mind when selecting your cement that this product is also hydrophilic and hence it can absorb water and tends to expand on setting when this occurs.
In general, it is not recommended that this cement be used in cementing full porcelain restorations because of this property–you might introduce internal stress on the porcelain if the cement expands. Note: Infinity is a flowable version of Geristore (DenMat) which is a resin reinforced glass ionomer, FujiCem (GC) and RelyX Luting Cement (3M/ESPE) are other popular brands. Ketac-Cem (3M/ESPE) is a glass ionomer cement.
All ceramic crowns are strongest when bonded. When using a resin cement such as Panavia, placing silane on the aluminum oxide is a common error. The Panavia adhesion monomer bonds directly to the aluminum oxide. Dr. Ray Bertolotti says that Panavia F can be cured without the use of Oxyguard, whereas 21 needs Oxyguard on all the margins or it will not cure. Also while on the subject of Panavia, take note that except for the Lume5 (Ultradent), present LED curing lights will not cure adhesives and composites that lack the commonly used camphorquinone photo initiator (e.g. Panavia F).
According to Dr. David Garber, the most popular brands of braided cord are Gingigel and Ultradent. The Ultradent cord packs more easily, but the Gingigel cord actually retracts better. The explanation for this is that the Ultradent product collapses easily but the Gingigel has an internal support so it remains fuller.
Dr. Garber also suggests always making sure that the cord is soaked with water before removing it, or you could tear the tender tissues causing hemorrhage if it’s dry. He also suggests trying the thin packing instrument by Ultradent.
IN OFFICE BLEACHING TIPS
If you’re using paint on dam, make sure the tissues are very dry prior to application. LC Block Out resin material does the same job and might cost less. Taking an Advil pre-bleaching takes a bit of the sting out of the buzz this procedure can leave you with for a day. A post fluoride rinse may help also. Keep Vitamin E oil available to place on areas of gingiva with bleach burns. This product can be purchased in bottles in the pharmacy or you can simply split open a Vitamin E capsule. If the burns are significant, send some capsules home with the patient.
To get the most oxidation from the bleaching solution, Dr. Malchmacher suggests applying it to the incisal one third on the lingual also, and then covering the whole tooth with Saran Wrap to force the bubbles to the tooth surface and not to loose them to the air. I take this one step further and use Whitestrips to cover the 35 percent solution applied to the teeth. I find plastic wrap very difficult to manipulate, but the Whitestrips are precut and the plastic is firmer. Also they contour nicely over to the lingual aspect. You can’t use gloves with plastic wrap as it sticks to them and then you risk getting bleach on your fingers, but you can handle Whitestrips with gloves.
Speed up your crown preparations and save money by using tapered fissure burs rather than diamonds and invest in an electric handpiece. Try a #8 round carbide bur to cut the gross margins and then follow up with the traditional diamonds.
SURFACE GLAZING OF RESIN RESTORATIONS AND PROVISIONALS
Last year, Oral Health published an article by Dr. N. Barghi, which studied different techniques to achieve the best shine on a resin restoration. He reported that the very best sheen was achieved from light curing the resin under a mylar strip. Unfortunately, you usually have to shape and grind the surface after removing the mylar, thus destroying that beautiful finish.
Some of the new polishing systems will get a nice polish without glazing (e.g. Shofu One Polish, Jiffy Brushes, Groovy Diamond Brushes). But there is a problem with finishing the restoration at this point. What we are creating is a polished smooth surface as opposed to a surface that will scatter the reflection of light and allow for unique surface textures.
You should be particular about what you glaze your restoration with. The concept is to convert the air inhibition layer to a smooth and lasting surface. Recently at a Toronto meeting, Dr. Barghi suggested using a wetting agent such as Wetting Agent by Ultradent or Discover by Bisco. The technique is to coat the shaped restoration with the wetting agent and light cure for 10 seconds. Then cover that cured surface with seven percent glycerin gel and light cure for an additional 20 seconds.
Watch the market for loads of similar new products e.g. Gloss and Seal (DenMat), Quik Glaze, and now Quik Glaze White (All Dental Prodx) to lighten provisionals. Cure times may vary depending on your light.
Sealants and bonding resin are not recommended as the best products for this application for the following reasons. Sealants are liquid unfilled resin and will weaken the surface and bonding resin contains
hema, which will discolour the restoration. Flowable resins are bonding resins plus fillers, so they generally contain hema also.
The gel you use to cover the cured wetting agent must also be chosen with care. Try to get a pharmacy to make up a seven percent glycerin gel (inexpensive), or use commercially available products such as the blue gel in the Panavia kit or De-Ox (Oxygen Barrier Solution) by Ultradent. Do not use petroleum or K-Y Jelly for this purpose. K-Y is full of water and can cause a pitted surface.
TECHNIQUE IDEAS FOR POSTERIOR PLACEMENT OF RESIN
After using resin modified glass ionomer (e.g. Fuji II LC-GC International or Vitremer-3M/ESPE) and/or flowable resin on exposed dentine, etching and conditioning, try a layer of composite resin to coat the inside of the matrix band (Composi-tight-Garrison Dental, Palodent-Dentsply-Caulk, Microbands-Dental Innovations) and while using a translucent point (e.g. Contact Former from LM-Multi Holder), pushed against the contact, light cure. Now you’ve gotten the contact point dealt with and your Class II prep has been simplified to a Class I situation.
The next step should be accomplished in increments. Place resin on either the buccal or lingual wall and angle it obliquely to the prep floor. Have the patient bite down and then light cure it. Do the same for the opposite wall and then fill in the central groove to the appropriate height. Check and correct the bite and shape for aesthetics. Then don’t bother with all your polishing systems, just brush on your wetting agent, light cure for 10 seconds, apply the 7 percent glycerin solution and light cure 20 seconds and you are done.
Better still, get yourself an LED or ARC curing light. It is an incredible pleasure to cure in five to 10 seconds, and resin restorations won’t seem half as tedious and you will be less likely to cut corners.
RESIN PLACEMENT INSTRUMENTS
Having an assortment can be very helpful. Some of my favorites are Ivoclar’s/Vivodent #1, Gold Microfill Contouring Instrument (Almore), IPC Composite Instrument (Cosmodent). I like an explorer tip for small preps and old football amalgam burnishers are handy too. Garrison dental has a new line to look at also.
CLEANING PLASTIC INSTRUMENTS
Extra care has to be exercised to remove all debris off plastic instruments during scrub and ultrasonic steps as once they’ve gone through a heat cycle it is very difficult to remove debris and the nonstick properties of the blade will be lost.
CLASS IV SHOW THROUGH SOLUTION
By now this technique should have reached you. When doing a Class IV restoration, place a thin layer of higher value resin (lighter) on the lingual and overlay it with a labial resin that matches the patient’s enamel. For even better aesthetics, you can take this one step further and sandwich a middle layer of more opacious (dentine shade) resin to simulate the lost dentine and even mamelons.
WHITE LINE CLASS III PROBLEMS
Everyone seems to have their own solution for preventing this. Placing a buccal bevel seemed to be a popular idea. Recent thinking is that, the cause of the white line may be related to the curing of the resin and the newer LED curing lights might help.
FLOWABLE COMPOSITES AND AIR BUBBLES
These air bubbles originate from air in the needle tip and can be problematic in restorative dentistry. Dr. Tom Hughes suggests storing them vertically rather than the usual horizontal fashion, might prevent the air from the tip floating deeper into the syringe.
ULTRSONIC CLEANING OF DENTURES, BITEPLANES AND ORTHO APPLIANCES
If the glass beaker of your ultrasonic keeps breaking like mine, try using a zip-lock bag with your solution and the appliance inside, thrown into the ultrasonic unit. Also, be cautious when using certain ultrasonic solutions to clean jewellery. Some of the cleaners meant for dental use may harm jewellery. I was told that Proclean (Premier Dental) does not recommend using their product for this purpose.
GOOD NEWS IF YOU AREN’T INTO RUBBER DAM
It has been demonstrated that bonding resin strength is not affected whether there is a dam present or not. This makes sense since we are doing wet bonding. This is not to diminish the attributes of using rubber dam, but rather to diminish guilt if you don’t use it.
COOL PRODUCTS TO TRY
Garrison Dental is marketing a new cotton roll that is novel and I really like them. Called Dry Rolls, they have a fibrous paper-like coating and solve issues related to cotton rolls such as sticking to tissues and fibres getting into restorations. They are very absorbent. When you call to ask for a sample, inquire about their Composi-Tight Gold matrix bands. Since using these bands I have had patients complain that their resin contact points were too tight on flossing! Big on resin restoration solutions, this company also distributes a terrific resin finishing kit.
Safety-Wipes (All Dental Prodx), are little sponge-like wipes that substitute for 2×2 gauze. Try a sample of these, they could be very handy for hygiene and endo. They have grooves in them that you can add antiseptic in.
Many companies have developed their own version of the new small particle size hybrid resins. Because of the competition to get these new products into your offices, most companies will send you samples if you ask them. Each product has slightly different properties, so you are wise to try a few before settling on a favorite.
Wright Dental is marketing an Intro Kit ($63.05) from LM-Multi Holder Instruments. It contains two holders and 48 tips. The tips include the clear contact formers (16), clear cervical matrices (16), 12 gingival retractors and 4 implant scalers and are reusable.
Oral cancer in women, young people, non-smokers and non-drinkers has increased 15 percent in the last 45 years. It has a higher incidence now than cervical cancer or melanoma. At 50 percent, it has a poor prognosis for survival. Most oral cancer lesions first appear as a small white or red spot or sore that is usually asymptomatic. Oral CDX has developed a ‘brush biopsy’ that can be done in office and is general dentist fiendly. Most fee guides have soft tissue biopsy codes for this procedure. For information, contact 1-877-672-5722 or www. oralcdx.com. To order kits, call Sullivan-Schein at 1-800-560-4467. Request sample photo sheets of early oral cancers to distribute to all your staff members.