Reestablishing a patient’s lost natural dental esthetics is one of the most important goals of modern dentistry. General dentists routinely take on the challenges of patients who are self-conscious about the appearance of their teeth. Whether that includes tooth color, shape, structure, position, or a combination of factors, esthetic problems in the anterior region are primary drivers of elective care.
Unfortunately, many patients have chosen to postpone elective care in light of the ongoing COVID-19 pandemic. June 2020 data from the American Dental Association (ADA) Health Policy Institute (HPI) indicated many practices (63%) were open but practicing at a lower patient volume than usual. Another ADA HPI research brief released around the same time revealed that dental spending among Americans is expected to continue to decline in 2020 before making a comeback in 2021.
A break in the “normal” routine has presented clinicians with an opportunity to revisit common elective procedures that patients will request upon their return. If there’s a less invasive way to achieve highly esthetic results in the anterior, now is an ideal time to explore those techniques and revamp your material armamentarium.
Indirect restorative techniques in the anterior
For years, esthetically satisfying results in the reconstruction of anterior teeth have been achieved with full-coverage crowns. However, this treatment option can result in the removal of large amounts of sound tooth structure. Procedures also may have an adverse effect on the pulp or periodontal tissue.
More conservative treatment options emerged with the introduction of adhesive systems. Unlike full-coverage crowns, laminate veneer restorations – whether direct or indirect – are a less invasive approach and do not require excessive tooth preparation that could damage surrounding tissue.
Compared to direct composite resin bonding, indirect composite veneers have been reported to provide a superior alternative for esthetic modification of teeth. Successful treatment using the indirect technique can help preserve tooth structure while providing excellent esthetic results and patient acceptance.
In addition to esthetically unsatisfactory restorations, other indications for anterior indirect restorations include enamel hypoplasia, waves, stains, and grooves; enamel abrasions; congenital imperfecta amelogenesis caused by hormones or tetracyclines; chromatic or dystrophic alterations caused by fluorosis; coronal fractures located primarily on the palatal side; volume anomalies (microdens); diastemas; and alignment defects.
Indirect ceramics vs. Indirect composites
Veneering ceramics have been used for more than 50 years with good success rates, but they have certain disadvantages compared to indirect veneering composites. Veneering ceramics are known for their high color stability, high biocompatibility, and high abrasion stability, but fabrication can be time-consuming and technically demanding, and the restorations can be abrasive to opposing natural tooth structure.
Indirect composites, on the other hand, have proven that they’re capable of protecting tooth structure, delivering esthetic results, and preserving function. They have improved mechanical and physical properties based on their chemical compositions, including resin matrix, filler particle type, filler size, filler percentage, and filler bonding (silane coupling agent). These properties are affected by temperature, environmental conditions, and polymerization unit light intensity.
Compared to veneering ceramics, most indirect composites are applied with a post-curing process that results in superior flexural strength. Some studies have found that longer light exposure and post-curing with heat improve the properties of prosthetic composite resin materials, and the failure probability of composite resin-veneered restorations is not significantly different from that of metal ceramic restorations. Additionally, indirect veneering composites exhibit minimal polymerization shrinkage and a wear rate comparable to tooth enamel.
Indirect composite restorations using modern materials
After diagnosis and tooth preparation, the indirect restorative workflow begins with a highly detailed impression. Dental impression materials continue their evolution, evidenced in recent years by the release of several high-performance vinyl polysiloxane (VPS) materials.
Designed for accurate interocclusal records of bite registration, the Regisil 2X VPS registration system (Dentsply Sirona) accurately records occlusal details, enabling the clinician to easily seat models with a slight amount of elasticity and minimizing interferences from convex tooth surfaces. It also enables minimum resistance to the patient’s jaw closure to minimize deviation of the mandible and aids in producing consistently accurate centric relation records.
After internal research revealed that nearly three in four dentists wanted an impression material that’s better suited for not only the ideal cases but all cases they see, Dentsply Sirona developed Aquasil Ultra+ Smart Wetting Impression Material. This VPS material off state-of-the-art intraoral hydrophilicity and intraoral tear strength to help capture and maintain detail.
Similarly, Refl (Patterson Dental) is a super-hydrophilic VPS impression material with excellent characteristics to ensure accurate, distortion-free impressions. Reflection offers excellent elastic recovery, thixotropic handling for good flow under pressure, and does not slump.
Imprint 4 (3M) is a super-hydrophilic VPS impression material available in Regular Set and Super Quick Set Times and in multiple viscosities and work times. Imprint 4 displaces moisture right from the start to reproduce fine details even in moist environments. The innovative self-warming technology enables the material to rapidly heat up to body temperature, accelerating the setting reaction but not setting until the end of the working time.
KaVo Kerr has a long history in developing high-performance impression materials, and those efforts culminated in the release of Take 1 Advanced VPS impression material. Take 1 Advanced is formulated to deliver an optimum combination of physical properties, including excellent tear strength and elongation. Available in a wide selection of set times, delivery systems, and consistencies, it serves as a hydrophilic wash material that displaces intraoral fluids and registers detail in any environment.
EXAFAST NDS (GC America) is a fast-setting VPS impression material developed for improved accuracy, increased productivity and maximized patient comfort. It’s convenient and easy to extrude with desirable handling and produces crisp, smooth, and highly precise impressions quickly. Clinicians have 60 seconds of working time with a 90-second set time, according to the manufacturer.
All of these VPS materials can be used with Patterson Disposable Plastic Impression Trays, which are made of a strong, rigid material that helps create consistent, distortion-free impressions. The trays are pre-shaped and can be easily trimmed or flame softened to adjust the fit. Their perforations optimize the flow and retention of materials, and they offer a nonslip grip for clean, easy removal.
Fabricating the indirect composite restoration
A good impression material should yield a highly detailed model that the clinician will use to fabricate the indirect restoration. Clinicians can now choose from a number of technologically advanced composite materials that offer a variety of structural and esthetic benefits.
For more than a decade, nanohybrid composites have represented the latest generation of material innovation. They are designed to represent the best of hybrid and microfilled composites, offering three qualities clinicians most desire: adaption and sculptability, natural esthetics, and reliable longevity.
Filtek Supreme Ultra Universal (3M) is a nanocomposite offering excellent esthetics, polish retention, handling, and strength for the anterior and posterior. It is available in 36 shades and four opacities and indicated for indirect restorations, including inlays, onlays, and veneers.
In the TPH Spectra ST family (Dentsply Sirona), SphereTEC fillers work in harmony with TPH Spectra ST resin to deliver excellent strength, durability, and stain resistance. For esthetically demanding anterior cases, the fillers and resin together enable an excellent chameleon effect for simplified shade matching. One universal CLOUD shade is all that’s needed for most cases, according to the manufacturer.
Harmonize is KaVo Kerr’s next generation of nanohybrid universal composite infused with Adaptive Response Technology (ART), a nanoparticle filler network that helps clinicians achieve lifelike restorations with more ease and simplicity. The ART filler system diffuses and reflects light in a similar way as human enamel, for an enhanced chameleon effect, according to the manufacturer. It also offers easier handling with adaptive viscosity and consistent polishability with ProGloss.
GrandioSO Heavy Flow (VOCO) is indicated for Class I to V restorations, with high-quality esthetics and blendability that make it suitable for use as a veneer cement. With low shrinkage and packable-like wearability, GrandioSO Heavy Flow is ideal for proximal and cervical areas as well as for use with GrandTEC glass fiber systems. It is available in VOCO’s patented NDT (Non-Dripping Technology) syringe in multiple shades.
Prime and bond
After fabrication, it’s time to etch the tooth surface in preparation for bonding the composite veneer. Multiple etchants and bonding agents with their own unique benefits are available.
Patterson Etch Gel is 37% phosphoric acid that quickly etches tooth enamel in preparation for bonding in about 15 to 20 seconds. This thixotropic gel offers nonslump and precise placement – simply agitate the gel to lower its viscosity. The etchant gel is easy to use with a leak-free syringe that allows for direct extrusion and facilitates faster procedures. It has a blue tint for high visibility and precise placement, and it is available in two convenient package sizes.
Xeno IV (Dentsply Sirona) is a one-component, light-cured, self-etching, and self-priming dental adhesive. It is fluoride releasing and designed to repair metals and ceramic and bond composite and compomer materials to enamel and dentine. The reduction of components and treatment steps minimizes technique sensitivity, achieves high-bond strengths, and protects against microleakage while minimizing the risk of postoperative sensitivity.
MonoBond Plus (Ivoclar Vivadent) is a universal, single-component bonding agent for all indirect restorative materials, generating a sound bond between the restoration and cementation material. It enables users to achieve a strong and durable bond to any dental restorative material because it combines three different functional methacrylates.
Adper Single Bond Plus Adhesive (3M) is a fast, easy, and convenient total-etch, single-component bonding agent. It offers excellent bond strength thanks to its ethanol/water base that helps maintain shear bond strength over time to yield an outstanding shelf life. It is indicated for indirect bonding procedures, including veneer bonding.
OptiBond Universal (KaVo Kerr) is a singlecomponent lightcure adhesive that provides excellent adhesion to a variety of surfaces and substrates for direct and indirect applications. OptiBond Universal is formulated to simplify the bonding procedure, making it less technique sensitive. It can be used with self-etch, selective-etch, and total-etch techniques, and its low film thickness helps create a better final restoration fit.
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This article was originally published in OnTarget. View the full publication here.