PFM vs. Zirconium for Anterior Implant-Supported Bridge?

Anon, Zirconia is very strong. My doctors use this when they want aesthtics with maximum strength. Zirconia is not fracture proof but has a strength close to a PFM. Zirconia has a flexural strength around 1200 to 1300 MPA as compared to Empress 2/ Emax between 300 - 450 MPA. A PFM flexural strength is around 1400 MPA. Zirconia is able to mask out metal implant abutments. How long is this bridge? That will determine what system you use for zirconia. I like working with LAVA by 3m ESPE. The cores are shaded (not just on the surface)and has a good fit. Other systems like Procera, Everst, Zeno, Prizmatic, Cercon, Cerac in-lab and a host of others have only white cores or only one shaded core. I have used many of these in my lab, and still achieve good estheics with all of them. These system names are for the cores and the machines that design and mill them. The layering porcelain usually is determined by the lab that finishes the crown or bridge. Not all labs offer these systems and although most are designed and milled by machine, people still enter in the information and tell it what to do. I might have given you more info than I needed to for a post, but if you need further help, I can give you a number to contact me in another post.

Zirconium works well. Where I have seen it have problems if the abutment has to be adjusted/prepped, then I've seen crazing and chipping. If it is a custom abutment, they usually work extremely well.

There are many more factors to consider such as length of clinical crowns, width and length of pontic areas, guidance, size of connector areas and type of occlusion. As a manufacturer of zirconia understructures, Procera has the longest track record and when Nobelrondo porcelain is used as an overlay, it is the most esthetic and chip resistant material on the market. That is my opinion.

Metal-ceramics opposing zirconia-ceramics should not be a problem, especially if the occlusal forces are properly managed. Only muscle can supply the force to wear the opposing dentition. Be sure to restore the case in centric relation with anterior guidance to disclude the posterior teeth and coordinated muscle function will be maintained. The esthetics of the newer generations of zirconia based porcelains are exceptional, especially Herceram and Noritake. Be sure the zirconia frame is designed properly to support the porcelain. Most porcelain to zirconia failures are cause from improper support of the porcelain, especially in cusp-tip-to-marginal ridge type occlusions. Anterior frame designs are a challenge for many of the CAD/CAM systems and the incisal edge position ends up way to far facially. For most cases, the zirconia frame can be designed just fine, and an exceptional result achieved. Esthetics with zirconia based porcelains can be far superior to any metal ceramic restoration.

I believe that the zirconium implants will take place of all of titanium and titanium alloy implants in the near future. Zirconium oxide implants now has HIP (Hot Isostatic Post Compaction)process;In this process, the material is reprocessed after the sintering process by being further compacted in a tunnel oven for three days at 2000 bar,which significantly improves the physical characteristics of the base material and the blocking mechanism prevents cracking ceramic;so it is 4 times stronger and 3 times flexible than titanium. Zirconium implants are esthetic, stable (does not give ions in the body unlike titanium), nonallergic and one piece implant. Because of one piece implant there is no gap between body and abutment and no peri-implantitis. I have inserted about 60 Z-Look3 implants in this year I have had only one lock ball failed implant. Because of the screws are round there is less post operative pain and swelling. Recently I have learnt that FDA has accepted this implant system and the dentists in USA will begin to use them. This system is completely metal free implantation.

The above posts supply a lot of good information. What I will add is this: the ceramics need to be well supported, so I would consider how big the crown will be, especially in relation to the abutment. Having worked as Implant Coordinator in a dental lab, I learned to LOVE Atlantis abutments for their computer aided design. For maximum esthetics they can make a ceramic abutment, too. Make sure you are using a high quality lab with lots of implant experience; they can help guide you with the best choice of materials. Also, I (and Gordon Christensen)consider nightguards a highly underused modality in dentistry. I include nightguards in my tx plans for implant patients, C&B patients, as well as (and especially) veneer patients. This way, everyone sleeps better at night (pun intended).

Personnally, I would not place any all ceramic bridge with a span longer than an upper lateral incisor. The procedure should also be preceded by a statement to the patient to the effect that the treatment is new and has not had the test of time. Be prepared to remake it as the lifespan could be unusually short. New is not necessarily better as manufacturers like to make claims for new products that have not had the test of time. As Dr. Schwartz mentions a night guard should be included and used. Good luck.

I am somewhat concerned about a statement made about the "fragile" nature of something like LAVA as a substrate. If one has not tried to cut one of these restorations off, it is harder to cut than any metal we use. I have used LAVA as a base for inlay retained bridges of molars. I would not hesitate to use for two pontics. I certainly would use in for splints crowns and anywhere in the anterior where a pontic is supported on each side by an implant.

Dr.Sandalli: Just remember Zirconia is a metal. One of several forms of zirconia oxide! To call it metal free is not accurate As far as its fracture toughness that is questionable. Alot is known about high strength ceramics in large and very thin sections. Much less is known in the sizes we need them to be. Bridging or what you are calling blocking has not been clearly demonstrated in the sizes we use. Besides this strength we always hear about are only tested in the lab in a dry mode. All of the properties of the high strength ceramics are not the same in the oral cavity. They do crack, and they may "heal" The flaw is still present. As it functions under load, not force, oral fluids are hydrolically pumped into the crack until it fails. In the end its not so much about the material but more about how the patient lost their teeth from the start, and using stratigies to avoid failure of the restored dention for as long as possible based on the patients needs. All of this stuff with ceramoceramics on a non segmented zirconia implant remains to be seen. So much of the strength gathering in function may now be passed on to the implant bone interface w/o appreciable energy loss dissapation. Remember what the FDA did in 1998 with certain types of hip implants. Maybe there is an excess of this mateerial in the universe and now given to dentistry. Caution advised! How strong is strong enough?

I am about to have 10 zorconia crowns put in. In your opinion is zorconia better than metal fused to porcline? I am concerned not knowing the long term. Pleaes advise. Many thanks!

I realize this is a forum for professionals, but I am beginning to feel semi-pro from hours of web surfing to research my own dental crisis: I had facial trauma at age 25, losing tooth #9 and breaking 8 and 10. These were root-canaled and I had a ceramic on metal bridge for 20 years that was ugly but worked OK. When that failed due to pin fx, I got an Empress bridge with a "build-up on a build-up" and was warned this would not last long. (I was in a rush to complete my transcontinental bike ride). It was beautiful and lasted 8 years before the build-up failed last week. Now I am advised to get implants in place of 8 and 10, rather than re-do the root canals. The periodontist wants to use Astra-tech, he despises NBC for various reasons. The esthetic dentist is planning zirconium abutments and procera restorations. I would like to know if I may eat an apple, etc, but no one can really say. The implant guy would rather I used titanium abutments and bridge. The esthetic guy thinks I will not be happy with gray gums. I have been told not to pursue an implant for #9 since it has been 28 years sans tooth, and I would need a bone graft, with extra time and expense, and less esthetic outcome ("black triangles"). I live in a semi-rural area, and neither of these guys have a ton of experience. What would you advise me to do?

Hmm, it would seem that what most people want out of this thread is "is Zirconia better than a PFM" and "will my expensive treatment last". I often remind my patients that "the original set of teeth that they were born with didn't last a lifetime", hence anything artificial may also follow the same fate. Zirconia has high flexural strength of up to 1400MPa. HOWEVER, this reduces by up to 20% after the first year from the effects of hydration. Additionally, as stated in the posts above, ZIRCONIA, weakens, sometimes as much as 40-50% of the original strength upon modification by grinding or sandblasting/microetching. I think one needs to be philosphical about this. Just as a $30,000 car rarely sees us through 10 years of use (or maybe 15 years), a $10,000 zirconia bridge may not last a lifetime. I would be happy to see it last 10 years! However, one needs to think about WHAT the variables are that led to the loss of the ORIGINAL teeth to start with (poor oral hygiene, bruxism, parafunction) etc.

Can some one compare the all porcelain vs zirconium bridge for front lower teeth? 3 unit bridge. I would like to know the long term life, looks of these two options.