November/December 2005, Volume 1, Issue 2
Published by AEGIS Communications
Using an Auto-Dispensed Composite Core Build-Up Material
Robert C. Margeas, DDS
Patients often present with large restorations or fractured teeth that require extensive treatment, leaving clinicians to choose from many material options to restore them. Which material should be selected? Should an amalgam be chosen to restore the lost tooth structure as a build-up under a crown?
Amalgam has been used successfully for many decades and is still identified at many dental schools as an ideal restorative material. When using amalgam as a restorative build-up under a crown, the problem of possible galvanic reaction exists if the definitive restoration is fabricated with a different alloy. The presence of dissimilar metals in the oral cavity creates small currents. Thus, the irritation produced by the current generated when a gold restoration opposes an amalgam restoration, for example, may on occasion cause sensitivity.1 Also, when placing all-ceramic restorations, amalgam’s high modulus of elasticity—in contrast to that of ceramic materials—may be a contraindication for its use in that clinical situation.2
Historically, when endodontic treatment was performed, the cast post-and-core was a standard procedure. However, the literature indicates that the possibility of root fractures and excessive removal of sound tooth structure, resulting in a weakened tooth, can occur.3,4 If conservative endodontic therapy is performed with a minimal access opening, then a post is not necessary. Composite resin can be used to restore the opening.
When indirect alternatives are selected, multiple appointments and laboratory fabrication expenses increase the cost of the procedure. As a possible result of this, it is this author’s observation that there has been increased use of direct core build-up fabrication procedures using composite resin. For both endodontically-treated and vital teeth, the use of composite resin as a direct core build-up material has gained popular acceptance over the last several years.5
Characteristics of a New Core Build-Up Material
A new material to aid the dentist when confronted with deciding which core build-up technique to use has recently been introduced. The CosmeCore system (Cosmedent,® Inc., Chicago, IL) is an auto-mix composite core material specifically designed for the fabrication of core build-ups.
This material is dispensed with an application gun and auto-mix tip, eliminating the need for hand mixing. It is easily placed in the tooth and will not slump, often eliminating the need to use a matrix band. The mix is predictably consistent because the base and catalyst are auto-dispensed in equal amounts. Therefore, clinicians only use the amount of material needed, without encountering the problems of too little, too much, or wasted material.
This core build-up composite is available in 3 shades (blue, white, and A-2). The blue material is used under all metal or porcelain-fused-to-metal (PFM) restorations; it is easily distinguished from tooth structure. The white and A-2 shades are ideal under all-ceramic restorations or for endodontic access closure.
CosmeCore is a dual-cure material that stacks well, according to the manufacturer. The material will bond to itself, so additional material can be added to it once it is initially cured.
When placing a post, this core build-up material can be injected into the canal space following standard bonding protocol, thereby eliminating a separate cementation procedure. The manufacturer notes that the material demonstrates a high compressive strength, which contributes to durable, long-lasting restorations. A 4-year study involving 200 patients has demonstrated that a fiber-reinforced core resin system is superior to the traditional cast post-and-core procedure.5
A patient presented with a fractured maxillary left bicuspid that required core build-up and placement of a full-coverage crown restoration. In pbodyicular, the buccal cusp was fractured (Figure 1 and Figure 2).
A fourth generation bonding agent was used, for which the primer (All-Bond® 2, Bisco, Inc., Schaumburg, IL) was applied to the preparation in multiple coats for 20 seconds (Figure 7). Then, a dentin/ enamel resin was placed (Figure 8) and light-cured for 20 seconds (Figure 9).
To fabricate the core build-up, the blue CosmeCore material was auto-mixed, injected into the preparation, and light-cured for 40 seconds (Figure 10 and Figure 11). Final preparation of the build-up was completed immediately after polymerization (Figure 12). Once complete, the core build-up—due to the use of the blue material—was easily discerned from the tooth structure.
The case presented here demonstrated the manner in which the CosmeCore system’s intraoral tips eliminated the need for loading the material into a different syringe for placement. Rather, the material was dispensed directly from the cbodyridge into the preparation. Additionally, it prepared similar to dentin while simultaneously releasing fluoride. According to the manufacturer, because this material can be bulk filled and cured to a depth of 5 mm in 40 seconds, the tooth can be prepared without having to wait for several minutes. In this case, the ability to prepare the build-up within 40 seconds after polymerization contributed to an efficient restorative procedure.
The author is the developer of CosmeCore and receives royalties from the sale of this product.
1. Phillips RW. Skinner’s Science of Dental Materials. 8th ed. WB Saunders Company; 1982.
2. Malament KA, Socransky SS. Survival of Dicor glass-ceramic dental restorations over 16 yrs. Pbody III: effect of luting agent and tooth or tooth-substitute core structure. J Prosthet Dent. 2001;86(5):511-9.
3. Abbott PV. Incidence of root fractures and methods used for post removal. Int Endod J. 2002;35(1):63-7.
4. Raygot CG, Chai J, Jameson DL. Fracture resistance and primary failure mode of endodontically treated teeth restored with a carbon fiber-reinforced resin post system in vitro. Int J Prosthodont. 2001;14(2):141-5.
5. Terry DA, Triolo PT Jr, Swift EJ Jr. Fabrication of direct fiber-reinforced posts: a structural design concept. J Esthet Restor Dent. 2001; 13(4): 228-40.
6. Ferrari M, Vichi A, Garcia-Godoy F. Clinical evaluation of fiber-reinforced epoxy resin posts and cast post and cores. Am J Dent. 2000;13 (Spec No):15B-18B.
About the Author
Robert C. Margeas, DDS
University of Iowa College of Dentistry
Depbodyment of Operative Dentistry
Iowa City, Iowa
Des Moines, Iowa