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6 Dental Tribune Middle East & Africa Edition | September - October 2013media cme mCME articles in Dental Tribune have been approved by HAAD as having educational content for CME credit hours. This article has been approved for 2 CME credit hours. Centre for Advanced Professional Practices (CAPP) is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. CAPP designates this activity for 2 continuing education credits. O ne of the challenges that we face in dentistry today is how to build a long- span bridge with maxi- mum esthetics in mind. In the age of implants, we can usually shorten the span by adding in a few implants or eliminate the need for a bridge all together by using implants to replace those missing teeth. However, what about those cases where we don’t have the quality or quantity of bone that we need, a me- dical history that won’t allow implant surgery such as free bleeding, a high- risk host such as a poorly controlled diabetic, smoker, etc.? Often times a patient doesn’t desire to go through the complex surgery of a sinus lift or bone graft to make an acceptable site for implants. Patients should be given the options and risks associated with each ap- proach and allowed to make an in- formed decision with the dentist’s guidance. For a missing tooth there could be five or more options presen- ted to the patient as ways to restore the space. a case history In 1998, a 39-year-old female presen- ted with an abnormally loose tooth #12. Upon radiographic and clinical examination, it was noted there was little to no root left on teeth #10–13. Teeth #8 and #9 appeared normal as did tooth #14. Her gingival health was optimal and her medical history was unremarkable, and she was taking no medications at the time. The patient recalled that when she was 14 years old she was hit in the face right above these teeth with a golf club during a friend’s backswing, which probably lead to the resorption of the roots of the teeth in question. All options and risks were explained to the patient. The sinus floor was 3 to 4 mm from the crestal bone. Implants with a sinus lift to allow room for placement were discussed. The patient did not like the idea of surgery and the healing time that would be required for a perma- nent restoration. A partial was discussed; however, the young patient did not want to have a partial and was worried her esthetic demands would not be met. More options for less permanent treatment were offered, but the patient did not desire them. The patient choose to do a long-span bridge, double abuting on teeth #8 and #9 with pontics to replace teeth #10–13 and using tooth #14 as a di- stal abutment. This would meet the patient’s demands for esthetics and be a non-removable restoration. She would have the permanent restorati- on in less time than it would take to undergo implant therapy. Porcelain-fused-to-metal was used on the original bridge work done in 1998. The highest noble metal con- tent available that could span a four- pontic length was used. The porcelain work was done with a layered porce- lain technique to provide a life-like appearance. In January 2012, the patient, who was now 52 years old, presented with a broken tooth. She was eating a peppermint, incised it with the distal of tooth #8 and fractured the porce- lain in an incisal gingival direction. About 2 mm of porcelain came off toward the distal contact. The metal substructure of the bridge was showing. The piece of porcelain was intact. She was on her way to a meeting she could not get out of and desired a temporary fix. I tried the piece of porcelain in and found it to be adequate but not an exact match for fit. Some of the por- celain had chipped away and was lost. I rough-ened the surface of the bridge in her mouth in the area that needed the repair then placed K-etchant Gel by Kuraray to clean the area. I used Alloy Primer from Kuraray on the metal substructure. On the porcelain, I placed Clearfil Ceramic Primer. Clearfil Majesty flo- wable composite was placed on the metal and on the piece of chipped porcelain. I refit the porcelain and light cured. All of these materials to do the repair are readily available in the Clearfil Repair Multi-Purpose kit from Kuraray. It makes life simple to have eve- rything you need in one place. The patient was able to get on with her day and made it on time to her meeting (Fig. 5). You can see the repair on the distal of #8. material selection In the pre-op photo (Figs. 1,3, 5) you can see there is the telltale sign of a metal allergy to the metal that is in the bridge. The dreaded “black gum” look. In addition, there is a difference in height of the gingiva on teeth #8 and #9. The patient had already made the choice of a bridge, now we had to decide which material to use. The patient reported that she has metal allergies to jewelry unless it is gold. So odds are high that any metal we use that is not 80 percent gold or more is going to cause a metal aller- gy and the dark gingiva. However, a metal that high in gold will bend on this long of a span, so we ruled out the use of metal. By eliminating the me- tal, the “black gum” look will go away (Figs. 5, 6). BruxZir was the material of choice for this case. BruxZir is a solid zirconia material that is sold to laboratories in a pre-sintered disk. CAD/CAM tech- nology is then used to design and mill the restoration. BruxZir Zirconia exceeds the flexu- ral strength of typical zirconia (up to 1,465 MPa versus 1,200+ MPa for ty- pical zirconia). BruxZir exhibits three to six times the fracture toughness (also known as the K1C value) of ty- pical zirconia. To better understand this concept, consider that a piece of steel or lead has high fracture toughness, whereas glass or brittle materials have a low K1C value. This property gives it high impact resistance. It also has excellent resistance to thermal shock. This low thermal expansion means the resto- rations will remain very stable in the mouth. BruxZir is available in all the Vita Classic shades. Due to the esthetic de- mands of the patient, a mono- lithic colored restoration would not be ac- ceptable. By performing a “cut back” on the facial of the bridge, we could achieve the desired esthetics and have the necessary strength. The advantage of BruxZir zirconia over other zirco- nia frameworks with overlay porce- lain is that the lingual and occlusal surfaces do not have the opportunity to de-bond or chip. The old bridge had metal lingual on #8 and #9 (Fig. 3) and a metal occlu- sal surface on tooth #14. This allo- wed minimal tooth reduction. Using BruxZir allows us to use the same minimal reduction, as low as 0.5 mm, thus conserving tooth structure. In addition, BruxZir allows us to have the esthetics desired with no additio- nal reduction (Figs. 3, 4). If using a zirconia framework system that required full-contour porcelain, we would need to reduce tooth #14 substantially. This theoretical reduc- tion would give a clinical height on the prep of around 1 mm. This would be an insufficient ab- utment for a bridge of this length. Minimal preparation of the tooth structure, especially on #14, makes BruxZir an ideal material. Additional considerations were given to try to balance this smile. The pati- ent wanted to change the anatomy of #7 and add a little more length. A ve- neer was added to this case on tooth #7. IPS e.max lithium disilicate by Ivoclar Vivadent was chosen for the veneer material. IPS e.max lithium disillicate is an all-ceramic material that is available in a millable block or pressable ingot using the lost wax technique. IPS e.max CAD blocks have a flexural strength of 360 MPa versus 400 MPa for the IPS e.max press ingot. Blocks and ingots are available in va- rious shades and levels of opacity to achieve a final shade match. A stump shade is recommended for IPS e.max due to the level of translucency. IPS e.max press was used for the veneer and is indicated for anterior crowns and bridges with one pontic as well as posterior single units. A gingival recontouring procedure to match gingival heights was performed on teeth #8 and #9 using radiosurge elec- trocautery. lab portion This case was sent to Oral Arts Dental Laboratories, a full-service lab located in Hunstville, Ala. I took a stick bite to establish the horizontal place along with full upper and lower impressi- ons and bite. Once the model work was completed, the models and dies required digital scanning. BruxZir is a CAD/CAM-fabricated material and thus must be digitally designed by a technician using a digital scanner and design software. Once the final contours and design Esthetic Long-Span Bridge Using BruxZir by mark mcomie, dmd ________________________ Fig.1: Full face with the old bridge. (Photos/Provided by Dr. Mark McOmie) Fig.3: Lingual of old bridge with metal lingual and occlussal surfaces on the abutments. Fig.5: Notice the porcelain repairs on the distal of tooth #8 on this old bridge. Fig.4: Lingual of new bridge; the BruxZir material allows us to have full contour with the desired esthetics without having to reduce any more than would be required with metal. Fig.6: Black at the gingiva is gone on this new bridge, and the gingival collar is more uniform. Fig.2: Full face with the new BruxZir bridge and IPS e.max veneer on tooth #7.