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In this article we describe the “Carrot Model” technique, also known as the “Geller Model”. Model work is a step that is often neglected by dental technicians, or in some cases a task that is assigned to the least experienced person in the laboratory. We disagree with this philosophy and strongly believe that model work is a crucial step in the fabrication of a dental prosthesis. As a reminder, this is the first phase in any new case and subsequently, the precision achieved on a porcelain crown/veneer will have no meaning if the cast is not treated with proper care. Additionally, the cast is our only reference of the patient’s mouth, and it is the link between the laboratory and the dental office. This significance is the reason why we developed a reliable technique to achieve a highly esthetic and precise model.
What is One Body Concept? It is feldspathic based, blended porcelain which gives the option of A, B, C and D shade possibilities. The product was invented with the goal of saving your laboratory time but still delivering high accuracy and fewer remakes through repetition in shading. How is it different? One Body offers a one-color porcelain build-up powder so does not require an enamel translucency build-up. Instead, those characteristics will be yielded with GC Initial IQ Lustre Paste, a porcelain particle with stain, since One Body is not meant to be applied on the incisal area. One Body Concept works with conventional porcelain alloys, but by using only one porcelain powder.
As we have all noticed, the field of dentistry has been flooded with new computer technology. The latest inventions are CAD/CAM and digital impressions, all revolutionary and intended to improve the working lives of clinicians everywhere. But what about dental technicians? Has all this technology changed the way they create their restorations? For the most part, no, it hasn’t affected the way they are layering porcelain at all. Technicians are using a tried and true system and since it works, there has been no reason to change. And frankly, in my opinion, layering porcelain is still the best way to create life-like restorations most of the time. But what about the rest of the time? Has anyone invented another way to get the same results? That is what we will discuss in the following case studies, along with how to communicate better information regarding patient shading.
There was a time when the fastest high-speed handpiece only went 3,000 rpm’s. The air turbine handpiece was introduced to dentistry in the 1950’s, which sped up the high-speed handpiece to 400,000 rpm’s. I’m sure dentists were thrilled with the change. Now, we can’t even imagine practicing dentistry without high-speed handpieces. For dental laboratories, the last 10 years have revolutionized the standard PFM into highly esthetic, precise fitting Cad/Cam restorations. Dental professionals, both dentists and dental laboratory technicians are embracing change in nearly every part of their practices.
In my practice, taking predictable, accurate impressions and bite registrations has always been one of the more difficult procedures to perform consistently. Did the patient hold still while the impression and bite were setting? Did I miss any tears, voids or pulls when reading the impression? Will the lab be able to read the margins? Even as advances in impression materials have improved, the patient variables continue to offer daily challenges in most practices. As technology advanced from improved dental impression materials to digital impression systems I’ve been able to once again take the quality, accuracy and esthetics of my crown and bridge practice to the next level.
The extreme Class-II and severely compromised periodontal condition left no other choice but extraction and placement of implants for this patient.
With the kind of spectacular solutions in mind which have become commonplace thanks to ZIRKONZAHN, a plan was hatched to deliver the best possible outcome with regards to function and aesthetics.
A light-cured base plate is used for the diagnostic set-up (mock-up frame): Tooth placement for the ideal aesthetic appearance is the primary concern; actual abutment positions are only of secondary importance at this phase. The set-up is tried in situ. Fit, function, phonetics and aesthetics are confirmed before the case is full contour duplicated in ZZ-FRAME, a dimensionally stable polyurethane with high filler content.
Situation: When preparing crown and bridge over implants, I often have the occlusal access holes in the aesthetic zone. Cementing the restoration in place prevents me from retrieving the restoration for maintenance or repairs.
If there is anything sure about zirconia, it’s that zirconia remains misunderstood on many levels. Dental manufacturers speak of their superior quality zirconium, their better techniques of milling it, and how their colorizing process is the one known not to produce a loss in strength of the material. As dentists, we continually hear these boasts, many of which may be unsubstantiated by valid studies. This leaves a lot of confusion when trying to compare information from various companies.
There is another area of concern for us however, which is the way zirconia restorations are handled in our offices. We must assume that manufacturer’s claims are honest and accurate, and also that lab technicians are following the recommended protocols during fabrication. Now that the zirconia based restoration is in our hands, care must be taken to avoid any of the no-no’s that can compromise the integrity, hence longevity, of the restoration. Here are some points to consider when handling zirconium in your office:
In part 1 of this article, the author discussed the “Press-over-technique in combination with the staining technique”. He used as an example a three unit bridge with a metal margin and a bridge fabricated with this combination technique. Part 2 will outline the technique on how the pressed-over metal-ceramic in combination with the build-up layering is produced.
Indications: Combination of metal-ceramic and Press-over, Press ceramic, Press-over (pressed ceramic over metal frame) Staining Techniques, Layering Techniques and Combination Technique.
This article will be concentrating on the pressed to metal ceramic with the combination of layering porcelain. It is our opinion that this technique has big advantages: the quick fabrication of one or more precise ceramic margins, and then the individualized layering with precise control from start to finish of the work.
In dentistry, the patient’s increasing desire to take aesthetic factors into account has become of substantial importance over the past years and this has dictated the need to create crowns and bridges without a metal support. This need has, consequently, resulted in an acceleration of the research for extremely innovative materials and amongst these we find Zirconia with which structures of outstanding strength and having remarkable advantages in terms of Bio-compatibility, hardness and aesthetics are obtained.
A short introduction is necessary here to explain this innovative material suitable for a wide variety of uses:
• Zirconia is an advanced ceramic defined as a bio-ceramic or bio-material.
• It is obtained from a mineral found in nature called Zircon.
• The Zircon mineral is chemically defined as a Zirconium Silicate and belongs to the Nesosilicate sub class.
Said mineral is mainly composed of Zirconium (Metal ore) which, combining in a natural manner with silica and oxygen, forms the mineral itself whereas, when reacting with oxygen, forms a thin crystalline layer of oxide on its surface chemically known as Zirconium dioxide or better known as Zirconia.
Thanks to the introduction of Zirconia in our laboratories we are now able to overcome several problems among which the possibility to reconstruct a complete full contour morphology of the teeth in Zirconia while having an excellent chewing functionality and protecting the aesthetic ceramic from chipping and cracking at the same time. Said results highly satisfy the expectations of both the Doctor and the patient.
The PRETTAU BRIDGE is a novel type of implant restoration: A zirconia bridge milled to full anatomical tooth contour – Guaranteed NO chipping!
Porcelain chipping – the dirty word and most clinicians’ phobia. The dreaded cusp shear within the layered veneer ceramic. A symptom that frequently occurs with implant restorations.
Lack of occlusal load-control (no nerve endings to implant abutments) as well as flaws in framework design or inadequate veneer porcelain support cause such failures. Enrico Steger sets new standards with his Zirkograph and the tight quality control of Zirkonzahn zirconia with its constant nonvariable shrinkage factor.
The new Zirkonzahn Prettau Zirconia marks a significant technological advance indicated for full anatomical-contour milled crowns and bridges. The exciting possibilities of this new material are demonstrated in Aldo Zilio’s Prettau-Bridge for ‘Mamma Luca’.
Aldo Zilio lives in Creazzo - Italy, half way between Verona and Venezia.
In Venezia one finds more than four hundred bridges, a lot of them not even known by name. Many lead the visitor into glorious palaces. These bridges, though historic monuments in their own right, worthy of admiration, are often barely noticed by the casual passer-by.
Not so the Prettau-Bridge: The new full anatomical-contour milled zirconia restoration after Enrico Steger seems already assured fame and glory but see for yourself.
Aldo Zilio’s case presentation points the way in modern oral bridge design:
Every dental technician seeks to restore the individual oral aesthetics of the patient. To approximate this as closely as possible, the wax-up has become a standard part of my daily work in the natural reconstruction of teeth. It takes a bit of time, effort and experience to prepare a good foundation for the definitive restoration within an appropriate time. The fact that this is worthwhile is revealed over the course of therapy. The wax-up determines the framework design. At this stage, the foundation is laid for statics. The wax-up is also an important criterion for the appearance of the definitive restoration, and it helps meet the patient's desires. Dental esthetics and the perception of harmony are not absolute values. Each person experiences them in a different way. It is nearly impossible to harmonize all the participants’ ideas with the static requirements without using the wax-up as a planning tool.
The basic concept of the wax-up is very simple and quickly explained. The patient receives an initial impression of the definitive results of his prosthetic restoration by the oral try-in of the wax-up. His wishes and thoughts can be incorporated in detail. Information about the realistic possibilities of successful treatment and the patient's input ensure the patient's trust and motivates him. This trust can have a major influence on the acceptance of the prosthetic. Of course, the wax-up also has a substantial influence on the work of the dental technician. He obtains a precise idea of the final restoration and is thereby able to pursue a specific goal. In general, we can say that the try-in of the wax-up simplifies the entire procedure and makes the prosthetic restoration reliable and predictable.
The single anterior can be the most difficult tooth to recreate in cosmetic dentistry. The dental technician challenges include shade mapping, the selection of material for the understructure, longevity and, of course, don’t forget function.
The patient came in with an existing crown on tooth 8 and did not like the esthetics. The crown was removed and a post and core was completed. Impressions were taken and the tooth was provisionalized. The dentist and the dental technician did the shade mapping. A full-color mapping of all the colors in the patient’s tooth was completed. The patient was looking to match perfectly tooth 9. The patient was told the choices and procedures available and an all-ceramic restoration was chosen to give him the higher esthetics he sought. One of the issues was that the understructure would need to block the gold core from shining through. The understructure material should be opaque to mask the underlying dark color. However, an advanced porcelain technician can still mask the underlying dark tooth color by utilizing porcelains with detailed color-masking techniques. It is vital to avoid excessive opacity, which is common in porcelain-to-metal restorations and often results in lifeless-looking restorations. On the other hand, if you have too much translucency, the restoration looks too gray and dark. You may see this on some of the all-ceramic restorations that are less than 1mm in thickness. Metal-free restorations are not going to entirely replace porcelain fused-to-metal, but it is an alternative for more natural looking restorations. It is a dental technician’s responsibility to be educated about the latest materials, techniques and proper function of occlusion and muscle position for esthetics, longevity and comfort. The dental technician needs to look at how long a material has been on the market and should review studies that have been completed about the material. With a wide range of all ceramics to choose from, it is difficult to keep up with all of the new or improved products. With the changes happening so quickly, it can be confusing.
Some of the choices of materials or understructures are as follows: