Cercon

Cercon™ consists of a yttria-stabilized zirconia coping or framework that is layered with dentin, body and incisal porcelains for outstanding, beautiful metal-free aesthetics for entire mouth.

Cercon Zirconia High Strength All-Ceramic Restorations

Zirconia is a high-tech ceramic material that is characterized by its outstanding stability and biocompatibility, as well as strength levels significantly higher than other all-ceramic materials. In addition to strength, Cercon all-ceramic restorations display excellent aesthetics and precise fit characteristics.

When conventional cementation and maximum strength are vital factors in the selection of an all-ceramic material, Sun Dental Laboratories highly recommends the application of either Cercon or Lava Zirconia restorations. Here's an overview of the two systems:

Cercon Zirconia by Dentsply

Cercon consists of a yttria-stabilized zirconia coping or framework that is layered with dentin, body and incisal porcelains for outstanding, beautiful metal-free aesthetics for the entire mouth. Through the addition of yttrium oxide, Cercon delivers strength and fracture toughness (900 MPa's) far beyond other known aesthetic ceramics. Using CAM technology, SDL duplicates the prep model in a modelling material and designs the restoration in wax. The wax restoration is automatically scanned using a laser system and then Cercon base banks of presintered zirconia are milled in a low-density state. These milled copings or frameworks are then sintered (1350° C) at the laboratory to fully dense restorations and then layered with low wear porcelain.

Indications and Material Benefits

• Single-unit and 3 or 4-unit bridgework for the anterior or posterior region
  
  

• The all-ceramic option when maximum strength is required
  
  

• An all-ceramic option where conventional cementation is required - can be conventionally cemented or bonded to tooth structure
  
  

• Use for all-ceramic bridges with a maximum span of 38 mm in either the anterior or posterior region. Zirconia is the material of choice for all-ceramic posterior bridgework.
  

Contraindications

We do not recommend a feather edge preparation, as it does not provide adequate reduction for the porcelain build-up, or the trough or "gutter" shoulder because the outermost edge may not be detected when scanned.

Bonding/Cementation

Because of zirconia's high flexural strength, Cercon can be conventionally cemented with your choice of conventional or resin-ionomer luting cements. Cercon can be bonded to tooth structure if necessary.

Insurance Codes

Single Unit
D2740 Crown - Porcelain/Ceramic Substrate

Bridgework

D6740 Crown - Porcelain/Ceramic
D6245 Pontic - Porcelain/Ceramic

Prep Design

The optimal preparation is a shoulder or chamfered preparation with a circumferential step or chamfer which must be applied at an angle of 5° or larger (horizontal). The angle of the preparation (vertical) should be 4° or larger. The inside angle of the shoulder preparation must be given a rounded contour.

Choosing the right material for anterior restorations

Dentistry continues to roll through an "aesthetic revolution," with more restorative choices than ever to take better care of your patients. This multitude of information provides you with a tremendous opportunity to provide optimum care from an aesthetic, functional and disease prevention standpoint, however, it can also lead to confusion when deciding upon which option is best for your patients.

"Factors Affecting Restoration Selection"

By Dr. John C Cranham

Choose the material that's right for your patient

Perhaps nothing is more confusing than sifting through the myriad of aesthetic materials to choose the right product for any given situation. As practitioners, we have a tendency to get comfortable with one or two materials, and then make our patients fit the material. But that is not the best way to practice dentistry.

Know your options

A much wiser method is to spend time studying the advantages of as many materials as possible so you can consistently choose the right material to meet the demands of each individual patient. The purpose of this selection guide is to provide you with pertinent information necessary to assist you when considering the optimum treatment plan for your patients.

Material Selection Criteria

There are at least six factors to consider when choosing a restorative material. Let's take a look at each factor briefly.

1. Aesthetic Risk

   Typically 1.0-3.0 mm of maxillary incisal tooth structure shows at rest in a youthful smile. From this position, if the patient has a high aesthetic demand and shows a great deal of tooth structure (more than 7 mm of lip hypermobility when smiling), choose a material that is as cosmetic as possible.1 If the patient is not as driven by aesthetics and the teeth are not too visible, it is more sensible to choose a more durable material - even though there may be a slight aesthetic compromise.
   
   Another consideration is whether the underlying colour of the anterior teeth needs to be blocked or if the colour is to be visible through the restoration. A material should be used with enough translucency to allow the natural colour to shine through or enough opacity to block out unaesthetic underlying chroma.
   
   

2. Occlusal Risk

   When working up the patient's case, make sure to note any evidence of intra-articulator TMJ signs or symptoms, occlusal-muscle disorders, masticatory muscle soreness or fatigue (tension headaches), tooth wear, tooth mobility without periodontal breakdown, or tooth migration. These issues should be considered indicative of a high occlusal risk patient.2 aesthetic restorations may still be an option, but extra attention to detail is essential to develop an occlusal scheme that ensures a harmonious stomatognathic system - minimizing stress on the restoration.
   
   

3. Quantity of Remaining Enamel

   One of the best reasons to preserve tooth structure during an adhesive procedure is to conserve a maximal amount of remaining enamel, since the crystalline structure of enamel is far less variable than dentin. Recent reviews of porcelain veneers during the past ten years suggest that, of the restorations that failed (4%), six of seven were only partially bonded to dentin.3 While the success rate shows the wonderful results of porcelain veneers, it also indicates a need to preserve as much enamel as possible.
   
   

4. Quantity and Quality of Remaining Dentin

   Recent studies also look at how bonding to sclerotic and carious dentin can affect bond strength.4,5 While predictable bonding success is hard enough to obtain inside the mouth, it seems that bond strengths may also vary depending on the kind of dentin that exists. A good rule of thumb is to consider a traditional cemented restoration if areas of discolored dentin are present that lack sensitivity to cold water, air blast or to preparation without anesthesia. This evidence may indicate that the wet collagen network within the dentin has been significantly altered, affecting the necessary optimum bond strengths.
   
   

5. Ability to Maintain 100% Isolation

   If 100% isolation cannot be obtained during an adhesive procedure, failure is imminent.6 Deep subgingival restorations, patients with limited openings (TMJ), or any area that is impossible to isolate are pure examples of clinical situations where traditionally cemented restorations may be indicated.
   
   

6. Desire for Maximum Tooth Conservation

   Generally, it is recommended to only remove the amount of tooth structure necessary to maximize aesthetics, obtain the necessary retention and resistance form, and preserve remaining tooth structure.
   

References

1. Spear F: The maxillary central incisor edge: a key to aesthetic and functional treatment planning. Compend Cant Educ Dent 20 (6): S 12-S 16, 1999.9. Garber DA: Porcelain laminate veneers: ten years later. Part I: Tooth preparation. J Esthet Dent 5(2):56-S9, 1993.
   
   
   
2. Dawson P: Evaluation, Diagnosis, and Treatment of Occlusal Problems. C.V. Mosby, 1989.
   
   
3. Dumfahrt H, Schaffer H: Porcelain laminate veneers, a retrospective evaluation after 1 to 10 years of service: Part II: Clinical results. Int J Prothodont 13(I):9-I 8, 2000.
   
   
4. Yoshiyama M, Urayama A, Kimoch T, et al: Comparison of conventional vs self-etching adhesive bonds to caries-affected dentin. Oper Dent 25 (3): 163-169, 2000.
   
   
5. Nakajima M, Ogata M, Okuda M, et al: Bonding to caries-affected dentin using self-etching primers. Am J Dent 12(6):309-3 14, 1999.
   
   
6. Nakabayashi N, Pashley D: Hybridization of Dental Hard Tissues. Quintessence Publishing Co., 1998.