Advantages and disadvantages of Zirconia Crowns
The new era of dental materials is flourishing and much has to do with the advantages and disadvantages of Zirconia Crowns. Zirconia is an extremely strong and hard materiel, close to 1200 Mpa, compared to a traditional full porcelain crown at 250mpa. We measure in MPA’s or mega pascals. It is white and relatively opaque. So it is a great replacement for the previous metal that was used as a base underneath PFM’s, or porcelain fused to metal crowns. PFMs, were the standard of esthetic dentistry for the last 60 years or so.
Advantages and disadvantages of Zirconia Crowns
We are all familiar with the white crowns, that were relatively opaque, sometimes you saw a little metal sticking out at the gum line, causing a dark area at the neck of the tooth. These teeth were also often opaque and not terribly natural. This was because the metal had to be hidden by an opaque white color, so as not to see greyish in the crown.One problem was that the porcelain can chip off of the outside of the crown revealing an ugly grey color.
Zirconia crowns have overcome these problems. The zirconia comes either in small blocks that can be milled in a CEREC machine, or, as one of the few dentists in Israel with a Sirona Inlab system in my office, I can mill large restorations out of a puck of zirconia. Zirconia in its raw form is chalky. We mill it dry, and it needs to be put into an oven for 12 hours to sinter, or become hard. But once hard it is strong, tough and very exact in terms of its fit. One of advantages and disadvantages of Zirconia Crowns is that they are brittle. So we must be careful when adjusting the so as not to cause microscopic cracks which can lead to failure. All in all it is an amazing material and the advantages and disadvantages of Zirconia Crowns are far outweighed by the advantages.
Zirconia Crowns In A day
Zirconia Crowns In A day is one of the great breakthroughs in digital dentistry. The are only a handful of dentists in the country who employ CEREC technology, Dr. Ari Greenspan being the first. Let’s discuss Zirconia Crowns In A day.
Zirconia is a new form of dental material that allows us to mill it into a crown using CAD-Cam technology. We take a three dimensional image of the teeth, design that crown or bridge and then mill it on the spot. Zirconia oxide is a synthesized material that is exceptionally hard and has optical qualities similar to tooth. It has many advantages over standard porcelain fused to metal crowns, namely: esthetics, durability, strength and hardness as well as high biologic compatibility. Because it is milled and not cast in metal from a wax mold, there are virtually no discrepancies in fit. Until recently, the only way to get such a material for a crowns was through the traditionall’impression method. Another complication is that the zirconia is milled in an unfinished relatively soft states. It must then be finished and required hours and hours in an oven for a process known as sintering. The sintering requires special equipment that dentists don’t have.
Except in our office. We have recently started being one of just a handful of dentists in the entire country with the ability and equipment to produce Zirconia Crowns In A day using new and advanced technologies that reduce the sintering time.
The Inlab dental laboratory system is not really used by dentists because of the complexity. We wanted the ability to control every aspect of our lab work to ensure perfection. As a result, we now own a 5 axis sophisticated milling unit and the special ovens necessary to make Zirconia Crowns In A day.
If you have any questions please do not hesitate to contact us.
Porcelain has the unique ability to mimic natural teeth. They are a bunch of different types of Porcelain Crowns and each has its own advantages.
Traditional feldspathic Porcelain Crowns
These are a glass ceramic that achieves a high degree of aesthetic result, can work for decades. It is usually applied by hand using a porcelain powder. The technician builds up the crown using a paintbrush and is able to layer different subtle shades into the crown. It is used as a veneering structure on porcelain fused to metal crown (PFM).
different types of Porcelain Crowns
Glass ceramics with fillers
These different types of crowns are very ethic as well and much stronger and fracture resistant that a regular glass ceramic crown. They are also suitable for CAD-CAM systems allowing the dentist to scan the tooth in the mouth and create the crown digitally and then have the machine mill the crown out. One type of porcelain is E-max cad. It is Lithium dislocate materiel that comes in blocks. They are blue in color since they have yet to polymerize completely. Once the crown is prepared, the crown goes into a porcelain oven and we glaze it to make it shiny and we can give it some color to mimic natural tooth shades. It is really quite an amazing materiel. It then gets bonded onto the tooth with composite cement.
Glass-Free Ceramics, Polycrystalline
These are materials with alumina and zirconia. Porcelain crowns made out of these materials are very hard and durable. They are almost impossible to break and might be a good choice for people that grind their teeth. The one problem with them is that they are not so aesthetic and ignored to use them a layer of porcelain needs to fused onto the outside of the zirconia.
The cerec technology allows us to take a monolithic block of porcelain and create an exact a perfectly fitting restoration. The entire thing takes only about an hour from start to finish. The Cerec Blocks of porcelain that we use and place into the machine to be ground down into crowns come in several types of materiel.
Types Of Cerec Blocks
Cerec Blocks fall into 3 main categories and each has it’s own uses. The original blocks were standard dental porcelain. These blocks have been around for many years. The are strong, very wear resistant and very esthetically pleasing. The advantage of this porcelain is that it has expansion and contraction characteristics similar to tooth making it comfortable with very few post op sensitivities. It can be stained and glazed to individualize each crown. The disadvantage is strength measure in mega pascals. These Cerec Blocks are among the weakest and can fracture if under extreme stress. Usually though they are fine and I have found them fracture only under very unusual circumstances and even then only on second molars.
Next is E-max or lithium disilicate blocks. These blocks are the strongest options around, they are very esthetic and have the smallest chance of fracturing. In fact it is quite rare that that ever happens. The only downside is that these Cerec Blocks must be fired in an oven in order to make them have their final strength. That means they need an extra 1/2 hour of time in order to finish the procedure.
Finally there are hybrid blocks which are made up of composite material with porcelain components. The advantages of these blocks is that have a certain microscopic flexibility making them useful in high stress situations.
No matter which if these Cerec Blocks we use, today we have a wide range of different options allowing us to give our patients one visit crowns in an hour that are esthetic, strong and comfortable
Guided implant surgery
There have been great advances in dental implantology in the last number of years. One of the most important discoveries and implementation was that of combining the CAT scan, 3d xray technology, with something called guided implant surgery. Guided implant surgery allows us to place the implant virtually on a 3d image, achieving the best possible angle and location. Once we have chosen the exact location of that implant, we can create what is called a guide appliance. This retainer like device has holes milled into it at the exact location of where we previously virtually placed the implant. In addition, holes are drilled such that their angles allow us to drill precisely where we need to in order to get a perfect job done.
Another advantage of guided implant surgery is the fact that we can prevent some serious injury be pre planning the case. For example, the lower jaw has nerves running through it that give sensation to the teeth and lips. This nerve is the inferior alveolar nerve. One of the biggest problems that can happen while placing lower implants, is to drill too deep and do damage to the nerve. By doing guided implant surgery using a guide appliance, we know beforehand, exactly where that nerve is and the appliance prevents us from drilling too deep in the wrong location.
Here is how it works. Once we have placed our virtual implants, taking care to avoid any important anatomical structures like the inferior alveolar nerve, we must create a real model of the jaw as well as a model of the appliance that we will use during surgery. Today, the use 3D printers in dentistry is beginning to be seen more and more frequently. Because the computer knows exactly where we want those implants placed, we can print out the appliance all ready to be used for implant placement.
Dr. Ari Greenspan is a Jerusalem dentist. Our office offers an unusually wide array of dental services at the highest level of quality. Dr. Greenspan, a Jerusalem dentist, studied in The University of Medicine and Dentistry of NJ in the USA.
What is unique about Jerusalem dentist Dr. Ari Greenspan?
- Dr. Greenspan was the first dentist in the country to use the revolutionary CEREC 3d technology to form crowns in an hour.
- A great emphasis is placed on continuing education. See here for a complete list of his constant striving for improving and keeping updated.
- Jerusalem dentist Dr. Greenspan, is one of a handful of Jerusalem dentist’s who have the permission of the ministry of health to do dentistry under general anesthesia in his office.
- Dr. Greenspan also is one of a handful of dentists that perform frenectomies for babies who have a tongue tie and have nursing difficulties.
- The office performs a large amount of esthetic dentistry including full porcelain crowns in Jerusalem as well as porcelain veneers.
- Naturally, we also do implantology placing dental implants as well as doing sinus lift surgery and bone grafting.
- We have an active dental hygiene program offering patients the ability to upkeep their mouth in a state of health.
- We offer childrens dentistry done by Dr. Joel Cohen Jerusalem dentist who is a graduate of Hadassah dental school and an expert in pediatric dentistry. Dr.Cohen has worked for the Ministry of health’s dental division
- We offer facial pain, TMJ and sleep apnea treat performed by Dr. Larry Lockerman, Jerusalem dentist who practices in the Boston facial pain clinic as well as in Jerusalem.
For more information on Jerusalem dentist Dr. Ari Greenspan at 02 679-8040
Israel has long been at the forefront of computerized dentistry. The use of digital x-rays , CT’s and CAD-CAM dental restorations has been around for 20 years or so. We were the first office in the country to adopt the CEREC porcelain dental crown system.
Having just upgraded to the new Cerec Bluecam, I wanted to share some thoughts on what this means for my patients. CEREC blue cam is a state of the art dental 3d capture device. It allows us to avoid taking messy goopy impressions of your teeth, and allows a simple digital image to do the job.
Then, on the screen we design your restoration together and we see magic as the computer itself makes the crown fit between your teeth. Some adjustment is usually necessary by the dentist but we quickly reach the point where with the press of the button the milling unit literally create the crown out of a block of porcelain. It is computerized dentistry at it’s finest.
Here is one of the advantages of the new CEREC 4.2 software. It allows computerized dentistry to actually fit the models of the upper and lower jaws together digitally. It shows me exactly where the teeth all touch allowing our final restoration to have a perfect fit and bite.
Computerized dentistry has come into it’s own in the last decade or so. We can now restore dental implants using this system, as well as doing porcelain veneers. The fit is unparalleled and the esthetics and time savings are tremendous. There are a host of new materials that have been developed for this system and I have no doubt that we will see even greater advances in the future.
For now we can say without a doubt that CEREC is at the forefront of computerized dentistry and that it offers an unparalleled service to our patients.
CEREC Before And After Smile Design