Esthetic Materials — The New Millennium

During patient education, are you able to describe restorative options?

by Trish Jones, RDH, BS; and Kristine A. Hodsdon, RDH, BS

What restorative materials did you learn the most about while in dental hygiene school? Depending on the year you graduated, it was probably limited to amalgam, porcelain, and gold. With the emerging field of restorative/esthetic dentistry, the above-mentioned materials are no longer the only entrées on the restorative menu.

The explosion in the field of material technology and adhesives is revolutionizing the way dentistry is delivered. The emphasis on conservation of tooth structure, biocompatibility with gingival tissue, improved bonding with natural teeth, and cosmetic improvement has ignited rapid development.

Manufacturers are becoming partners with experts in research, academia, and private practice. Their goal is to develop materials with properties that will allow ease of handling, esthetically pleasing results, durability, and wear resistance. Since the research is constantly evolving, the restorative product "du jour" changes rapidly.

The contemporary hygienist, therefore, should research and learn about the newest advances in restorative dentistry. This effort allows the hygienist to discuss treatment modalities and guide clients to the best services for their individual clinical and "smile" goals.

This article provides general explanations of materials and their indications. It also is a forum to challenge your beliefs about what materials and procedures you favor or disfavor, and your reasons. Your opinions must be explored to ensure that you are pre-diagnosing and recommending treatments based on scientific findings — not unsubstantiated claims or misconceptions of modern materials.

When it comes to restoring a decayed tooth or replacing a defective filling, there is much confusion about what are:

• The best restorative products
• The best laboratories
• The best philosophies of care

Techniques also can be confusing. "Direct" techniques place the restoration chairside during the same appointment as the tooth preparation. Restorations using indirect technique are processed in a laboratory, requiring a second appointment for placement. Since there are no absolutes or best ways to treat a client, the following are some important variables to keep in mind to aid in the ultimate success of the restorative case. The selection of materials must concur with:

1. The specific situation
2. The technique for tooth preparation
3. The restoration fabrication technique
4. The luting/bonding agent
5. The restorative dentist's skill, judgment, and expertise
6. The laboratory technician's skill, judgment, and expertise (for situations involving indirect restorative systems)

Merging of occlusion and hygiene
Have you ever wondered why one tooth-colored material appears durable and remains esthetically pleasing in one client's mouth, while the same material is fracturing or breaking down in another's? Or when evaluating current conditions in a client's mouth, have you ever noticed an excessive amount of broken posterior teeth or restorations, tooth sensitivity, localized periodontal concerns, and or TMD problems? Have you ever noticed occlusal interferences during opening, closing, lateral, or protrusive movements? Clinical findings in these and other areas may indicate occlusal management problems.

Dental hygienists are not trained in school to recognize and understand the detailed connection between teeth and the muscles supporting the head, neck, jaw joints, face, etc. The solution is to take the initiative through continuing education to learn occlusion principles. Then, apply that knowledge during the pre-diagnostic examination. It will improve your contribution to the clinical success and longevity of restorative/esthetic and cosmetic dentistry.

For example, if you have witnessed clinical failures with some of the modern materials, it may not be the result of faulty properties in the product, but rather inappropriate case selection and lack of focus on comprehensive treatment planning that should have included the occlusal scheme and muscle forces. Therefore, if the client exhibits a pathologic occlusion prior to treatment, and it remains undiagnosed or not treated, then no matter what restorative material is used, the occlusal forces will either destroy the restorative material, the opposing dentition, or cause postoperative tooth or jaw pain.

In order for a restorative material to survive, clinicians must control as many biomechanical force loads as possible. If hygienists and dentists are not taking the time to provide a complete occlusal evaluation, then they should not be surprised or frustrated when tooth-colored restorations fracture, show signs of wear, or if they hear postoperative complaints about tooth sensitivity or jaw pain.

Understanding the essentials of occlusal and functional concepts support true comprehensive care and a total oral wellness plan. When you gain such insights, it will help break the cycle to pre-diagnosing the "Crown of the Year Club" or "tooth dentistry." Ill-planned crown or amalgam placements can lead to destructive consequences, such as fractured restorations or increased occlusal pathology. Learning about the intricacies of occlusion, the various occlusal theories, the appropriate pre-diagnostic evaluations, and the armamentarium for implementation involves a congruency amongst the entire staff. It can set the practice apart by providing full-mouth care in the community.

Direct materials
Composite-based resin materials contain an organic resin base and inorganic glass particles as filler. Composite resins are usually classified according to the filler particle size:

• Macrofill composites can have a particle size ranging from 10 to 100 microns
• Microfill particles can range from 0.1 to 1 micron
• Hybrid composites exhibit a combination of sizes, ranging from 1 micron down to 0.04 microns.

The newer materials have a greater resistance to wear compared to their predecessors because of the continual decrease in the particle size. The inorganic filler particle size and degree of filler loading determines the physical properties and clinical characteristics of the material. A few examples of the physical and mechanical properties of composites include: polymerization shrinkage/stress, hardness, bond strength, fluorescence, consistency and handling, shades, and depth of cure.

Polymerization shrinkage, or the metamorphosis of the material from a gel to a solid state via light or mechanical initiation, still continues to be a topic at the forefront of adhesion dentistry. Questions about polymerization abound: How much does a material shrink? How does the amount of shrinkage affect the adhesive bond of the material to the tooth structure? What light source or rate of curing is the most clinically appropriate?

These complexities are playing out in polymerization research and in scientific journals. The main concern to remember concerning excessive material shrinkage is that it may contribute to breakdowns of the margins.

Composite resin systems can be used in the restoration of anterior or posterior teeth. Anterior composites, usually microfills, can mimic enamel, are highly esthetic, have a high polishability, resist wear, and leave the control and artistry to the dentist. Examples of microfills include the following:

• Renamel (www.cosmedent.com)
• Amelogen Microfill (www.ultradent.com)
• Filtek A110 (www.3m.com/dental)
• Matrixx Microfill (www.discusdental.com)

Microfills can be used to replace enamel in class III, IV, and V restorations, diastema closures, and hand-sculptured veneers.

Posterior composites, typically hybrids, are indicated for the restoration of small to medium defects in back teeth, and can also be used for the replacement of broken or lost fillings. Even though hybrid material can be used for anterior restorations, hybrid composite materials with their strength and polishability are commonly used for posterior areas.

In the hybrid category, product examples are:

• Esthet-X (www.caulk.com)
• Renamel Hybrid (www.cosmedent.com)
• Vitalescence (www.ultradent.com)

These restorations are technique-sensitive and usually require the dentist to take a hands-on continuing education program to learn the corrective bonding steps. If performed correctly in a clean and dry operating field, they can require less tooth structure removal when compared to amalgam, and can strengthen the tooth.

The recognized placement techniques for composite resins are horizontal, oblique, vertical, bulk, and incremental. Commonly, the restoring dentist will use an incremental laying and polymerization technique. Composite resins up to 2 mm — the depth of each layer in the incremental technique — can be appropriately cured with standard curing lights to help prevent polymerization shrinkage.

Most documented research concludes that efficient light curing requires a curing device with a minimum energy output of 400mW/cm2.

Other types of composite resin systems include micro-hybrids, resin/glass ionomers, flowable composites, packable composites, and componers.

Indirect materials
Indirect restorative systems are continually evolving to increase options and popularity. Indirect restoratives are fabricated in a laboratory and cemented/bonded to natural tooth structure. This procedure requires excellent communication and collaboration between the dentist and the laboratory technician who is fabricating the restoration.

To further enhance your understanding of indirect restoration fabrication, a "field trip" to a referring laboratory may be the key. While visiting and touring the laboratory, you can gain insights to the skill and expertise needed to make these restorations. This new information can translate into greater confidence in your ability to create value for such treatments. This could unlock some doors to increase restorative/esthetic enrollment and case acceptance when discussing possibilities with clients.

Ceramic materials are the foundation for indirect restoration placements. They can be used for inlays, onlays, veneers, metal-free crowns, and crowns with metal sub-structures. Since many hygienists are more familiar with porcelain, specifically feldspathic, you may be wondering why the ceramic category has emerged so quickly. Porcelain, especially roughened or non-polished porcelain, historically is very aggressive against opposing teeth.

Newer Lucite-based ceramic products not only mirror natural tooth structure in appearance, fluorescence, and translucency, but they do not abrade the opposing dentition as aggressively as feldspathic types. Ceramic categories can be broken down into ceramics bonded, ceramometal restorations, and a variety of types that may not fit into a particular category (see the related chart).

Material technology has forever changed restorative dentistry. Basic clarifications of materials used for direct and indirect restorations have been presented above. Since our job as dental hygienists is mainly preventive, we should be evaluating the entire mouth, rather than just tooth by tooth. When you gain knowledge in occlusion, function, and the implementation of occlusal concepts, you will have the tools for breaking the habit of pre-diagnosing and recommending one filling or crown at a time.

Comprehensive care involves making sure that there is no parafunctional habits. The entire mouth is considered as a whole. Appropriate restorative materials are selected, and the dentist has the skill for placing such materials. The hygienist has the expertise in post-treatment management.

By expanding our sources for information to include occlusal and restorative data, we will gain self-reliance in educating our clients on all the benefits of the latest and best choices in occlusion and restorative/esthetic and cosmetic dentistry.

References available upon request.

Trish Jones, RDH, BS, is a technical adviser for Aurum Ceramic Dental Laboratories at the Las Vegas Institute for Advanced Dental Studies (LVI) in Las Vegas, Nev. She lectures dental team members on behalf of JP Consultants Institute about esthetic shade consulting, smile design, and post care of the esthetically restored smile. Kristine A. Hodsdon, RDH, BS, is a practicing clinical hygienist, author, and speaker throughout the United States. She is also the developer of Pre-D Systems™, which is a pre-diagnostic computerized team software module for comprehensive restorative and esthetic care. One of her latest projects is writing her first book, "Demystifying Smiles: A Resource for the Professional Team," to be published by PennWell in 2002. She may be contacted by e-mail at [email protected]. For information about Pre-D Systems or her interactive programs, visit www.pre-dsystems.com.

Indirect Ceramic MaterialsIPS Empress (Ivoclar-Vivadent; www.ivoclarna.com)Description: Leucite-reinforced pressed ceramic. Indicated for full coverage crowns, inlays, onlays, and veneers. Excellent for anterior restorations to full mouth reconstruction.

Advantages: Metal free. Accurately reproduces light transmission and translucency found with natural teeth. Excellent margin adaptation, and wear compatibility is similar to that of natural enamel. Not abrasive to opposing dentition, and maintains long-term function. Bonded.

Other information: Utilizes pre-shaded ingots and a unique pressing technique (lost wax technique). Utilizes Chromascop and Dentin Stump Shade guides or Vita Lumin.

IPS Empress 2 (Ivoclar-Vivadent; www.ivoclarna.com)Description: All ceramic material fabricated from lithium disilicate framework and a patented fluorapatite layering glass-ceramic overlay. Indicated for three-unit bridges (second pre-molar as most distal abutment) and full coverage crowns where strength is required due to occlusion.

Advantages: Metal free. Enhanced strength enables conventional cementation or adhesive bond. Natural translucency. Not abrasive to opposing dentition.

Other information: Enhanced strength. Not indicated for inlays or onlays. Use Chromascop shade guide or Vita Lumin.

Procera Allceram (Nobel Biocare 800-993-8100)Description: Densely sintered aluminous oxide core milled using CAD-CAM technology for optimal fit. Creates a very strong, nonporous bioceramic with the highest flexural strength of any ceramic system (687 MPa). Indicated for anterior or posterior crowns. Not indicated for inlays, onlays or bridges.

Advantages: Metal free. Durable, precise fit, biocompatible with soft tissues, and low wear against opposing dentition. Ideal for covering gold or metal posts. Allows light to pass through but won't show grey from post or amalgams. Restoration can be prepped and cemented like a PFM. Cemented or bonded.

Other information: Computer-aided dental design (CADD). Shape of prep is scanned into computer. Use with Vita Lumin shade guide.

In-Ceram Alumina (Vident; www.vident.com)Description: Indicated for crowns. Highly stable aluminum oxide substructure takes place of metal. Includes In-Cerum Spinell (mixture of magnesia and alumina) and In-Cerum Alumina (sintered skeleton-like meshwork infiltrated with a low viscosity lanthanum glass at high temperature).

Advantages: Metal free. Substructure is infiltrated with a fine layer of glass providing high flexural strength. Bond or cement.

Other information: Use with Vita Lumin or Vitapan 3D Master shade guide.

In-Ceram Zirconia (Vident, www.vident.com)Description: Indicated for bridges (pontic spans up to 14mm), and single posterior crowns. In the family of In-Ceram.

Advantages: Metal free. Extremely strong oxide framework, bridges can be cemented.

Other information: Use with Vita Lumin or Vitapan 3D Master shade guide.

Fortress (mirage; www.miraedp.com)Description: Indicated for crowns and veneers.

Advantages: Metal free. High strength, offers translucency, vitality and low abrasion. Surrounding glass matrix similar to leucite material — enhances light transmission.

Other information: Use with Chromascop shade guide, Vita Lumin or Vitapan 3-D master.

Porcelain MaterialsFeldspathic Porcelain (various manufacturers)Description: Traditional porcelain and layered porcelain. Can be used over metal substructure or by itself.

Advantages: Used mainly with PFM. Tiny sub-micro particles of ceramic that come in powder form.

Other information: Use Vita Lumin shade guide.

IPS D.sign (Ivoclar-Vivadent; www.ivoclarna.com)Description: Glass ceramic-fused-to-metal system. Can be used with Captek, high noble, or base metal. Indicated for use over metal substructure or by itself for inlays, veneers, or crowns.

Advantages: Patented formula consists of a fluorapatite leucite glass ceramic that mimics hydroxyapatite crystals in natural tooth structure.

Other information: High level of translucency, superior wear characteristics, true-to-life aesthetics, high polshability, enhanced shade stability.

Indirect Resin/Composite MaterialsCristobal+ (Dentsply/Ceramco; www.ceramo.com)Description: Indicated for inlays/onlays, full coverage crowns, Maryland bridges. Glass and polymer matrix creates a superior hardness, great strength, and superb marginal integrity due to its exclusive post-curing polymerization.

Advantages: Metal free. Wear rate similar to enamel. Compatible with all shade guides. Superior chairside polishability. Mechanically polished, not glazed, for long lasting lustrous finish and shine. Non-porous. Offers excellent esthetics and natural translucency that defies detection in the mouth. Bond.

Other information: Proven clinical success since 1993. Improved physical properties inhibit staining found with previous generations of indirect composite materials.

Targis 99/Vectris System (Ivoclar-Vivadent; www.ivoclar na.com)Description: Ceramic optimized polymer (Targis) combined with a fiber-reinforced composite framework (Vectris). High flexural strength. Indicated for bridges, full coverage crowns, inlay, onlays, Maryland bridges, and implants.

Advantages: Metal free. Possesses strength and durability of metal-based restoration, exceptional flexural strength, and elasticity similar to dentin. Durable, lightweight, and translucent. Bond.

Other information: Vectris is composed of fiber wafers (similar to fiberglass), and uniaxially oriented bundles embedded in an organic matrix. High tensile strength.

Sinfony (ESPE; www.espeusa.com)Description: Microhybrid composite designed to build up and layer like porcelain. Indicated for inlays, onlays, and veneers. Exhibits strength without introducing heat or thermal stress to the restoration.

Advantages: Metal free. Highly polishable and plaque resistant, low water absorption, has porcelain, and wax-like consistency. Bond.

Other information: Available in eight Vita shades.

BelleGlass HP (Kerr; www.KerrDental.com)Description: Polymer glass material cured in a high heat, nitrogen-pressurized atmosphere. Durable, opalescent composite similar to natural dentition.

Advantages: Great esthetics, enhanced wear, high polishability, gentle to opposing dentition, durable, and high flexural strength. Low thermal curing process minimizes microleakage.

Other information: Consists of materials: barium glass with BIS-GMA, and Pyrex glass filler, aliphatic, and urethane dimethacrylate. Use Vita Lumin shade guide.

Metal-Based RestorationsCreation (Jensen Industries, 800-243-2000)Description: Multilayered buildup technique, has fluorescence similar to natural teeth.

Advantages: Includes full range of dentin colors, can create mamelons, add surface staining, pearl enamels. Other information: Tissue-colored materials for matching soft tissue.

Porcelain fused to metal/ceramometal (various manufacturers)Description: Metal substructure available in precious/ noble metal, semi-precious/noble, and predominantly base/non-precious porcelain overlay.

Advantages: Cemented and durable. Use with Vita Lumin shade guide.

Other information: Used for more than 70 years.

Captek (Captek; www.captek.com, 1-800-921-2227)Description: Substructure of 97% gold matrix. Indicated for full coverage crowns and bridges. Warm hue from gold shows through porcelain.

Advantages: Precise fit, enhanced strength, and durability. Eliminates black lines. Combines high-purity gold and palladium-based alloy substructure. Porcelain butt margins promotes natural harmony with tissues.

Other information: Pure gold matrix eliminates grayish appearance that may result from traditional metal understructure.

Gold (various manufacturers)Description: Expands and contracts similar to a natural tooth. Indicated for crowns, inlay, onlays, and bridges.

Advantages: Exceptional fit, proven longevity, and functional success, high biocompatibility, and plaque resistance. Various percentages used depending on use.

Other information: Has been used for more than 2,500 years and can last a patient's lifetime.

Product Information Sheets
Ivoclar-Vivadent product information sheet (Empress 1 and 2)
1-800-533-6825

Vident product information sheet (In-Ceram)
1-714-961-6200

Nobel BioCare product information sheet (Procera)
1-800-993-8100

Kerr product information sheet (BelleGlass HP)
1-800-537-7123

Dentsply/Ceramco product information sheet (Crisotbal+)
1-800-487-0100

ESPE product information sheet (Sinfony)
1-800-344-8235

Aurum Ceramic Dental Laboratories product information
1-800-661-1169, www.aurumgroup.com