After thorough cleaning, the restorations are tried on with water. Using water instead of try-in paste or glycerin will allow for some surface retention without altering the color or masking the marginal fit. If the restorations sit passively on the prepared teeth and the doctor is happy with the color, it is not necessary to use try-in pastes. If, however, there is a dark tooth to be masked or the doctor would like to raise or lower the value of the final restorations, try-in pastes can be beneficial. It should be noted that try-in pastes should be water-soluble and match the shade of the luting cement after it has been light cured. Once the shade of cement has been selected, the restorations are carefully removed and kept organized by tooth number. During the seat visit, it is preferable to have six hands involved. If the doctor has only one dental assistant, we recommend involving a hygienist or other staff member at this stage of the procedure. While the restorations are being prepared for final seating, the doctor and chairside assistant are getting the teeth ready for bonding. I will address preparation of the restorations first.

The internal surface of all bondable porcelain restorations are etched with hydro- fluoric acid at the laboratory and therefore, it is not necessary to repeat this step chairside if the restorations exhibit the frosty appearance of etched porcelain. However, it is necessary to apply 35% phosphoric acid gel to the internal surface in order to aid in cleaning the surface of any contaminants and to acidify the surface before silanation. This is important because silane couplers are more effective on an acidic surface. The steps are as follows: the restorations are rinsed over the sink (with a cover on the drain), 35% phosphoric acid gel is applied to the internal surface, rinsed thoroughly and dried (the surface should be dry and frosty in appearance). Only the amount of silane necessary to coat the internal surface is applied, allowed to sit for a minute, and then dried again.

Finally, the restorations are painted with a thin coat of unfilled bonding agent and again organized by number and covered. It is important to note the coating of bonding agent serves to wet the internal surface of silanated porcelain and it should not be light cured.

While the restorations are being prepared, the doctor and chairside assistant are getting the teeth ready for the bonding procedure. The first step is to isolate with a rubber dam, thus allowing the doctor to work hands free and aiding in moisture control which is critical to the success of the case. When seating eight or ten restorations we recommend the split dam technique utilizing wingless clamps on the first molar.

After the teeth are isolated, they should be rinsed thoroughly to remove any remnants of try-in gel if used, and cleaned with Consepsis (Ultradent) to remove any surface contaminants and to disinfect, and rinsed thoroughly. Next, phosphoric acid gel 35% is applied to the surface of the prepared teeth using great care to keep it from coming in contact with the gingival tissues as this can result in bleeding. We recommend total etch and wet bonding due to the demonstrated higher bond strengths. The gel should be rinsed off after 15 to 20 seconds so it may be necessary to etch half the teeth and rinse, then etch the other half. The etch is thoroughly rinsed and the teeth should remain moist to maintain the delicate collagen matrix that has been created by etching dentin.

While the teeth are moist we recommend applying Gluma Desensitizer (Heraeus Kulzer) to aid in re-wetting if necessary, but mainly to help decrease post-op sensitivity. The teeth are lightly dried, or preferably, blotted, to remove excess moisture and the bonding agent is applied liberally in multiple coats. It is our belief that the 5th generation prime and bond one step systems are the best to use because of their ease of use, thin film thickness and high bond strengths. Some of the ones we recommend are Excite (Ivoclar), Optibond Solo Plus (Kerr), Prime & Bond NT (Caulk-Densply) and Single Bond (3M ESPE).

After multiple coats are applied, the teeth should be lightly air dried to volatilize the solvent while being careful not to blow out the resin that has penetrated the collagen matrix. The teeth can now be light cured because the thin film thickness of these materials will not interfere with the fit of the restorations. At this point, the teeth are ready to receive the restorations and since you will be dealing with light cured resin luting cements, the operatory light should be turned off to insure adequate working time.

There are many luting cements today that provide excellent handling properties and color. If the shade of the prepared teeth is light, it may be desirable to use a transparent or translucent shade, and if the prepared teeth are dark, it might be necessary to use whiter or more opaque luting cements or possibly even modifiers like pink opaque. Some of the luting cements we use in our courses with good results are Varolink Veneer, formerly Appeal (Ivoclar), Rely X Veneer (3M ESPE) and Vitique (Zenith DMG). They all have excellent handling properties and shade selections. Ivoclar has shades based on a value system with 0 being neutral or translucent, plus 1, 2 and 3 being higher value and minus 1, 2 and 3 being lower value. In addition to these common light cure only luting cements, there may be times when a dual cure cement is necessary. When bonding full crowns, onlay veneers, or even veneers that have been opaqued to mask tetracycline staining or dark teeth, it will most likely be necessary to use a dual cure resin.

It should be noted that luting cements will have little effect on the final shade of any restorations with a thickness of 1mm or more. When seating the restorations, the luting cement can be placed in the restorations, directly on the tooth, or both. However, when handling very thin veneers, it is often easier if the cement is syringed directly on the teeth. Once all the restorations are seated firmly in place, the excess cement (which should be evident around all the margins) is removed with cotton rolls and benda brushes, being careful to wipe in a gingival direction. It is often helpful to dip the cotton rolls and brushes in some bonding liquid to aid in removal of excess luting cement.

After cleaning the facial margins, the restorations are tacked in place. The technique we recommend is to use finger pressure on the incisal edge to seat in a gingival direction and a flexible instrument like a perio probe, held in the center of the tooth, to seat in a lingual direction. This pressure will often result in extrusion of more luting resin that can be wiped away by the assistant before tacking is completed. A 3 mm tacking tip is placed at the gingival margin and light cured for about three to five seconds. This will hold the restorations in place but will not cure the cement interproximally. The lingual margins can now be cleaned, as well as the interproximal margins, without fear of the restorations being dislodged. A technique we teach is to pass a Brasseler serrated steel saw blade through the interproximal contacts, followed by dental floss, to remove as much resin as possible before final curing.

The teeth are light cured for forty to sixty seconds on the facial and lingual surfaces. Clean up is now much easier because most of the luting cement has been removed before final curing. If there is any cured cement at the gingival margin it can be removed with a sharp scaler or scalpel blade. It is preferable not to use a diamond or carbide bur on the facial margins if possible. This can cause abrading of the highly glazed porcelain which is hard to re-polish and could lead to future staining and gingival irritation. A Brasseler 8379 red striped football shaped diamond bur is used to finish the lingual contours and make any occlusal adjustments that are necessary. The interproximal contacts can be polished with fine grit metal strips. Final polish is accomplished with rubber points and polishing paste.

It is well documented that adhesive dentistry allows dentists to successfully bond etched porcelain to enamel and dentin. It is, however, technique sensitive and a strict protocol must be closely followed. Being able to control and stop any gingival bleeding is one area of adhesive dentistry that is critical to the success of the case and cannot be compromised. Ideally, when seating the case, we would always like to have healthy tissue that does not bleed, but unfortunately, this is not always the case. As more and more gingival recontouring is done, with shorter intervals between the prep and seat appointments and patients that are not always compliant with home care instructions, it is not unusual to encounter some gingival irritation and bleeding during the cementation procedure.

There is a technique that we have been using in our programs that has proven to be very successful in controlling gingival bleeding. It involves using Viscostat (Ultradent), a 20% ferric sulfate hemostatic agent, Superoxol, hydrogen peroxide and Consepsis to control bleeding and clean and disinfect the teeth. When done properly, we have noticed sufficient working time to accomplish seating of the entire case without seeing anything postoperatively that would be considered a clinical failure, i.e. micro leakage.

It should be stressed that the technique we teach is not recommended by the manufacturer and has no scientific evidence to support it that we are aware of, but has evolved in our courses and the private practices of our instructors through trial and error and has consistently delivered long term clinical results in very difficult and trying situations.

The first step is to rub the irritated gingival tissues with the Viscostat using the patented infusor tip. This will provide hemostasis and allow adequate working time. If the tissue continues to bleed or begins again, this step is repeated. The problem with this product is that it is difficult to remove even with copious rinsing and any remnants of the ferric sulfate could cause discoloration and adversely affect bond strengths. Therefore, we recommend cleaning with Superoxol which is hydrogen peroxide in a higher concentration. It must be handled carefully because it is very caustic, but it will remove any remnants of film of the Viscostat and further aid in hemostasis. In fact, we often use Superoxol on a micro brush to control minor areas of gingival bleeding during cementation, but it does not allow very much working time when used by itself. Superoxol will clean the surface very effectively but presents another problem because it is difficult to rinse off. Therefore, after copious rinsing, the teeth are blotted with hydrogen peroxide to dilute any residual Superoxol. The teeth are again thoroughly rinsed with water and scrubbed with Consepsis to once again dilute, clean and disinfect the surface. This has all been accomplished after the teeth were isolated with a rubber dam and they are now ready to be acid etched. In addition to etching the enamel and dentin, the 35% phosphoric acid gel will also add one more cleaning step and rinsing cycle to our procedure.

So essentially, after hemostasis has been established with the use of the Viscostat, there are 4 cleaning, rinsing, diluting and disinfecting cycles. After the use of the Superoxol, which also contributes to hemostasis, there are 3 cleansing, rinsing and diluting cycles that enables the removal of any adverse effects of the hydrogen and oxygen bubbles. It is because of the many steps and the adherence to strict protocol that we believe we have been able to demonstrate long term clinical results with this particular technique.