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    Upgrading porcelain veneers Upgrading porcelain veneers Document Transcript

    • A full face view of the completed aesthetic upgrade.
    • www.oralhealthjournal.com  April 2011 oralhealth 41 e s t h e t i c s Upgrading Porcelain Veneer Restorations: A Case Report Robert A. Lowe, DDS Introduction Placement of indirect labial ve- neers (porcelain or composite) con- tinues to be an excellent option to correct many esthetic complaints that our patients may have with their smiles. Some of the more common indications for their clin- ical use include: 1) Minor corrections of anterior tooth morphology and emer- gence angles to fill in spaces in the gingival embrasure areas when these spaces are an es- thetic concern for the patient. 2) Minor corrections in tooth po- sition (rotation, labio-lingual arch position, and crowding) if orthodontics is either not in- dicated or accepted as a treat- ment option by the patient. 3) Diastema closures and correc- tions of anterior tooth propor- tion (golden proportion). 4) Establishment of anterior guid- ance and canine disclusion in patients where preparation for full coverage restorations would necessitate unnecessary removal of healthy tooth structure. 5) Improving tooth color for a patient where tooth whitening was not a treatment option or did not yield a satisfactory re- sult for the patient. Tooth Preparation The amount of tooth reduction re- quired depends on the specific clin- ical situation. In general, .5mm to .7mm of tooth reduction is needed. In some cases, where “nature” has done the tooth preparation or natural tooth contours are less prominent, “no prep” options are also possible. If changes in tooth position are required, some ar- eas of the tooth may be prepared more, others less. It is recom- mended to first contour the teeth to ideal position using a cylindri- cal diamond, then use depth cut- ters to remove a uniform amount of tooth structure to compensate for the thickness of the resto- ration. If in extreme situations, the dental pulp is encroached upon, root canal therapy is recom- mended rather than overcontour- ing the restoration. In cases where a low value (dark) preoperative tooth color is to be changed to a high value (light) color, more tooth structure may need to be removed (1.0mm - 1.5mm) to create enough space for opacious dentin or opa- quers to block out the darkness. For some patients, preoperative tooth whitening may be indicated to increase the value of the un- derlying tooth structure allow- ing for less tooth structure to be removed during the preparation process. Gingival margins should be placed at the gingival crest or slightly above. The interproxi- mal margins should be carried into the lingual portion of the contact area. If diastemata are present, the interproximal mar- gin of the preparation should be carried lingually to the linguo- proximal line angle. Also, when closing spaces, it is important to prepare the gingival margins far enough into the proximal areas so that the restoration margins are not visible from a 3 ⁄4 or oblique
    • 42 oralhealth April 2011 www.oralhealthjournal.com e s t h e t i c s of light bodied material when seating the tray and a less than desirable end result ensues from an incomplete seating of the tray. The difference here is the amount of light bodied material that is used. It is very important to inject only a small amount of light bod- ied material around the periphery of the tooth indentations in the heavy bodied material. The heavy bodied material will then force the light bodied material into the intracrevicular space around the teeth. The smaller amount of light bodied material allows the operator to more accurately seat the impression and gain sufficient “retraction” to force the light bod- ied material into the crevice. Provisionalization A fast and simple technique to fabricate provisional veneers uti- lizes a preoperative wax up as a template. Create a plastic pro- visional stent of the corrected view (when the patient turns their head to the side). After the prepa- rations are finished, it is recom- mended to use a fine cylinder finishing diamond to make the preparations as smooth as pos- sible. Aluminum oxide strips can be used interproximally to smooth and polish interproximal surfaces without compromising the proxi- mal contact. Impressions Since the gingival margin of most veneers will be slightly above the gingival crest, a very thin re- traction cord, such as a 00 or 000, can be placed in the sulcus and left in place during the impres- sion process. If a particular case requires subgingival margins, a #1 retraction cord is placed over the 00 or 000. When taking the impression, pull the #1 cord and leave the 00 or 000 in place. This “double cord” technique will pro- duce flawless intracrevicular im- pressions time after time. There is also a technique that can be used that will allow for an “anesthesia free” and “retrac- tion cord free” procedure. First, a stock tray is selected to fit the pa- tient’s maxillary arch form. Next, a heavy bodied tray material is injected into the tray and placed in the patient’s mouth. This will convert the “stock tray” to a “cus- tom tray” filled with set heavy bodied impression material. The next step will be to wash with a light bodied material...but a very important technique difference from a traditional “putty-wash” technique is used. When most cli- nicians perform a wash of a heavy bodied impression, the papillae between the tooth indentations are removed and the space is completely filled with light bod- ied wash material and reseated in the patient’s mouth. It is very hard to displace the large amount Figure 2—A full smile preoperative view. Figure 4—A view of the maxillary and mandibular minimal veneer prepara- tions. Note the value (brightness or darkness) of the prepared teeth. When fabricating porcelain veneers, the ce- ramist will lay down a thin opacious layer based on the “preparation shade” (stump shade), to block out the overall influence of that shade on the final vis- ible shade of the restoration. Figure 3—A retracted full arch preop- erative view. Figure 5—The completed first set of max- illary and mandibular porcelain veneer restorations after delivery. Figure 1—A preoperative full-face view of Michele prior to placement of her original set of porcelain veneers in 2002.
    • 44 oralhealth April 2011 www.oralhealthjournal.com e s t h e t i c s tooth positions using a vacuum former and .040 plastic mate- rials. After tooth preparation and final impressions, fill the stent with a bisacrylic provi- sional material and place over the teeth for two minutes. The patient can close in centric oc- clusion over the stent material during this time. After initial setting of the bisacrylic mate- rial, it can be removed from the stent and contoured with abra- sive discs and fine laboratory acrylic carbide burs. Any repair or addition to the provisional restoration is accomplished us- ing flowable composite material and light curing, either at the lab bench, or intraorally while the provisional restoration is in place on the preparations. It is not necessary to use bonding agents prior to the addition of the flowable resin if the sur- face is first roughened to cre- ate micromechanical retention. Also, the secret to successful addition of flowable resin to bisacrylic provisional restora- tions is to create a long bevel on the bisacrylic material, add the flowable resin to the repair area and continue to “feather” the flowable composite over the beveled surface of the bisacrylic 3 to 4 mm beyond the repair area. Finally, finish with abra- sive discs to original tooth con- tour and a seamless repair is created Cementation Placement of porcelain veneers can be accomplished using dual cured or light cured resin ce- ments. The veneers are first tried on individually to check margins, then collectively to evaluate contact and esthetics. A drop of water on the inside of the veneers can help to hold them in place for evaluation by the doctor and the patient. For most cases, transparent or clear resin cement will be Figure 6—A full smile view of the com- pleted initial aesthetic makeover. Figure 9—A retracted full arch seven- year postoperative view of the initial aes- thetic reconstruction. When compared with Figure 5, a definite change in tooth color of the restorations is apparent. Figure 7—A full face view of the com- pleted initial aesthetic makeover. Figure 10—A full smile seven-year post- operative view. Figure 8—A full face view of the initial aesthetic makeover seven years after placement. Compare this to Figure 7. It is difficult at normal speaking distance to perceive a change in the color of the restored teeth. Figure 11—The shade based on the Vita Lumin Shade Guide of the existing restorations is B1. The original restora- tion shade was “Hollywood White”, or bleached shade (B0). The patient’s desire is to have an upgrade to Bleach1 (BL1), which is the highest value of re- storative material available.
    • 46 oralhealth April 2011 www.oralhealthjournal.com e s t h e t i c s the cement of choice. There are some clinicians who report a color change with time when us- ing dual cure tinted cements. It is the opinion of this author that color change in older veneer cases occurs because of color change in the tooth, not in the 10-micron layer of cement between the por- celain and the tooth. The reason dual cured cements are selected by some clinicians is because of the ease of the clean up process. These types of cements will reach a “gel phase” about two minutes after mixing. At that time, the operator can use an explorer or fine curette to remove cement ex- cess prior to light curing. Dental floss can also be passed through the interproximal areas to be sure they are free of cement. While performing the cement clean up during the “gel phase”, the dental assistant stabilizes the restoration using finger pres- sure. Once the excess resin ce- ment is removed, the restorations are light cured. Using this tech- nique will minimize any rotary finishing, and polishing should also be kept to a minimum. Light cured cements can be used suc- cessfully if the operator has a tacking tip on the curing light and selectively “tacks” the center of the restoration on the tooth while leaving the cement at the margins uncured. The marginal excess is then removed with a brush, floss is used to clear the interproximal areas while stabi- lizing the restoration, and finally a total cure is done once the clean up is complete. As previously mentioned, some clinicians and researchers be- lieve that dual cure resin cements change color over time and affect the visual shade of the restora- tion. This may be true in the lab, but is this really happening clini- cally? If one takes a clear shade of resin cement, and an A3 shade, places a drop of each on a glass slide, then squeezes another slide on top of the cements to simulate a restorative interface and inter- esting thing occurs. It is difficult, if not impossible to distinguish between the two colors because the cement layer is so thin. How much color can be squeezed into a 10-micron layer of cement? How does that “change” become vis- ible behind an opacious layer of dentin porcelain followed by body Figure 13—The preparations after laser veneer removal. Note the resin cement is still present on the teeth. Figure 12—The Waterlase MD (Biolase Technologies) with a 600 micron tip is used to atraumatically remove the exist- ing veneer restorations. Figure 14—The preparations after polish with Enhance point (Dentsply Caulk) and minor margin refinement. Figure 16—Bleached shade provisional restorations are shown that have been placed after completion of the master impression. Figure 15—Retraction cord is placed prior to making of the master impression. Figure 17—A view of the newly fab- ricated high value maxillary central incisor porcelain restorations (Venus Porcelain: Heraeus Kulzer). PULL QUOTE
    • www.oralhealthjournal.com  April 2011 oralhealth 47 e s t h e t i c s porcelain? The “contact lens” ef- fect does allow the color of the tooth to affect the final shade of a restoration if the ceramist does not lay down an opacious material first or if the restorative gap is too large so that the cement layer is too thick.1-5 Case Report: Upgrading Porcelain Veneers Placement of the Initial Porcelain Veneer Restorations In 2002, my wife Michele ex- pressed a desire to have porcelain veneers placed to enhance the aesthetics of her smile. She pre- sented (Figs. 1-3) with a Class I occlusion and had very thin, opalescent enamel that did not respond well to tooth whiten- ing. Her desire was to have a “brighter, more youthful looking smile”. Following the methodology described above, the teeth were prepared using a minimal prepa- ration technique (Fig. 4), master impressed, and then provisional- ized using bisacrylic provisional material. A bleached white color of feldspathic porcelain was cho- sen, the restorations were fabri- cated, and finally cemented with a clear, dual cured resin cement. Figures 5-7 show Michele’s post- operative full smile, retracted full arch, and full face views respec- tively. Michele was thrilled with her new smile makeover! Seven Years Later... Michele had never specifically commented that she noticed her veneers were not as bright as they were when placed because there was such a gradual change over time (Figs. 8-10). Compare the post cementation photo, Figure 5 and the seven-year post op- erative photo, Figure 9. A sig- nificant color shift is very notice- able when performing a direct comparison of these photographs. Being surrounded by the dental field, Michele was also aware that newer porcelains were being developed that were brighter in value than those that were available when here initial aes- thetic restorations were fabri- cated. She therefore expressed a desire to have her veneers redone. Although a color change had been observed (Fig. 11), from a pure dental perspective, the initial restorations were still very serviceable, with no signs of fracture, wear, or mar- ginal breakdown. Knowing that conventional removal of these ve- neers with rotary instrumenta- tion would result in removal of more healthy tooth structure, the dilemma is whether to intervene and replace the veneers at this time, or to wait until such a time that the restorations breakdown and require replacement. As with most patients, Michele was not concerned with the potential loss of a tenth or two of a millimeter of tooth structure....she wanted brighter porcelain veneers! So, it was decided to grant her request and upgrade her aesthetic restorations. During this period of time, as an all tissue laser user, it had been discovered that the laser could be used to conser- vatively remove porcelain veneer restorations without further loss of tooth structure. It is believed that since the laser wavelength of the Er, Cr, YSGG laser seeks water, the resin cement is dena- Figure 19—The upgraded high value porcelain veneers cemented on the max- illary arch. Note the difference in value when compared to the mandibular res- torations that have yet to be replaced. Figure 22—A full smile view of the com- pleted aesthetic upgrade. Figure 18—Kleer Veneer light cured ve- neer cement (Pulpdent Corporation) is shown being placed into the porcelain veneer restoration). Note the complete lack of color in the cement. Figure 21—A retracted full smile view of the completed aesthetic porcelain veneer upgrade. Figure 20—This slide shows the removal of the initial mandibular ceramic ve- neers with the all tissue laser (Waterlase MD: Biolase Technologies).
    • 50 oralhealth April 2011 www.oralhealthjournal.com e s t h e t i c s tured and expands causing the veneer to fracture and separate from the tooth. The veneer can then be easily removed using a scaler (Figs. 12-13). Michele had ten porcelain veneers on her max- illary arch, all of which were completely removed with the la- ser in less than ten minutes! The cement layer remains visible on the preparation surface (Fig. 13). Next, an Enhance point, a com- posite polishing point (Dentsply Caulk), is used to remove the ce- ment from the preparation. Air abrasion can be used for this as well. After minor marginal ad- justment of the preparations to compensate of a small amount of gingival recession on the mid- facial of some of the preparations (Fig. 14), retraction cord is placed (Fig. 15), a new master impres- sion is made, and bisacrylic pro- visional restorations are placed (Fig. 16). The ceramist will now fabricate the newer, high value porcelain veneers. Figure 17 shows the finished central incisor restorations. A new light cured cement (Kleer Veneer: Pulpdent Corporation) is used to cement the newly fabricated porcelain veneer restorations (Fig. 18). Note that this veneer cement is totally transparent, unlike many other “untinted” resin cements on the market. It is the authors opinion that this type of cement is par- ticularly useful for very thin “no prep” veneers when blocking out tooth color is not required. At a subsequent visit, the process is completed on the mandibular arch. Figure 20 shows the man- dibular veneers being removed with the Waterlase MD (Biolase Technologies). The completed por- celain veneer aesthetic upgrade can be viewed in Figures 22-25. Note that clear porcelain was used at the gingival margins to gradually blend the root color at the restorative interface and make the margin less apparent. Conclusion “Wants based” dentistry, espe- cially that which is purely aes- thetic in nature, is often on a “different time table” than con- ventional restorative or rehabili- tative dentistry. Its “useful life” is not determined necessarily by marginal or occlusal breakdown, but by what the patient sees in the mirror. For some dentists, it is hard philosophically to remove and replace “serviceable” dental restorations. However, in this day of elective dentistry, we must re- alize that replacement of existing restorations can now be deter- mined on aesthetics alone....and this at any moment, is done at the sole discretion of the “wearer”. In the author’s case......”Happy wife......Happy life!! OH Robert A. Lowe, DDS, FAGD, FICD, FADI, FACD, FIADFE, Diplomate, American Board of Aesthetic Dentistry. Oral Health welcomes this orig- inal article. References 1. Strassler HE, Minimally Invasive Porcelain Veneers: Indications for a Conservative Esthetic Dentistry Treatment Modality, General Dentistry, November 2007 Special Edition, pp 686-694. Malcmacher L, No-Preparation Porcelain Veneers - Back to the Future, Dentistry Today Vol 24, No 3, March 2005. pp 86,88, 90-91. 2. Etman MK, Woolford MJ, Three-Year Clinical Evaluation Of Ceramic Crown Systems: A Pre­ liminary Study, Journal of Prosthetic Dentistry, Vol 103, No 2, Feb 2010, pp. 80-90. 3. Guess PC, Strub JR, Steinhart N, Wolkewicz M, Christian FJS, All Ceramic Partial Coverage Restorations- Midterm Results of a Five Year Prospective Clinical Splitmouth Study, Journal of Dentistry 37 (2009) pp. 627-637. 4. Lowe RA, Shade Instability: Examine a Root Cause of Mismatched Ceramic Restorations, Dental Products Report, September, 2008, pp. 116-122. Figure 24—“Happy wife.....happy life!”