Minimally Invasive Dentistry with the Latest in Nanotechnology Composite Resins
Using predictable materials and techniques to meet high patient expectations
Wynn H. Okuda, DMD
Now more than ever, there are high patient expectations for dentists to provide minimally invasive esthetic restorative treatment. The concept of minimally invasive dentistry (MID) is important to all dentists, as we treat these types of cases every week. It is important to understand how to predictably treat these cases so consistent results can be achieved.1,2 The philosophy of MID combines state-of-the-art material science with esthetic restorative techniques. The objective of MID is to remove caries-damaged dentition and restore it in the least invasive manner possible.
Achieving imperceptible esthetic results can be challenging unless predictable techniques and materials are used. Through the use of new and exciting materials, the most esthetic results can be attained in a reasonable amount of chair time. With predictable solutions, we will meet the high esthetic demands of our patients.
Composite resins have vastly improved through the years. The latest evolution in composite technology, G-ænial Sculpt™ (GC America, Inc., www.gcamerica.com), has to vast improvements in the physical properties that make this nanotechnology composite resin strong and beautiful. Improvements in the nanofiller technology are attributed to this progress.3 This composite resin features a high density and uniform dispersion technology for better wear resistance and gloss retention; it is also self-polishing for a long-lasting, shiny, mirror-like surface finish. The new high performance filler is additionally silane treated to help bind the filler to the resin matrix, thereby increasing the flexural strength.
A 28-year-old female presented with a broken incisal edge on her central incisor (No. 9) along with recurrent decay and a failing restoration on her lateral incisor (No. 10) (Figure 1). Upon examination, it was determined that a MID Class IV approach would be the best option for cosmetic restorative correction. In the past, bonding composite resin on an incisal edge could lead to short-term failure. However, good success can be attained with a composite resin that has excellent flexural strength.
First, minimal invasive preparations with scalloping bevel margins were done with micro-prep burs (Micro-prep bur kit, Komet USA, www.kometusa.com) (Figure 2 and Figure 3). Then multi-purpose G-Premio BOND™ (GC America) adhesive resin was used with a selective-etch technique. After etching the enamel with 32% phosphoric acid, the adhesive was placed for 10 seconds, then blown thin for 5 seconds using forced air. The adhesive was light-cured for 10 seconds (Figure 4). In addition to using this versatile adhesive resin with a selective-etch technique, it can also be used with a self-etch or total-etch method. According to the manufacturer, the result is a very thin (3μm) adhesive layer with high shear bond strength (35 mPa). Because of the resulting thin adhesive layer, G-Premio BOND can be flexibly used for direct (eg, G-ænial Sculpt) and indirect (eg, eMax, PFM, porcelain veneers) restorative dentistry.
There are several “keys” to achieving a successful Class IV restoration. Composite resin shade selection, preparation design, and sequence of composite resin layering are important for accurately blending the composite resin to the existing dentition.4 In addition, using the correct finishing and polishing technique is equally essential in obtaining a seamless and invisible esthetic restoration.
In restoring both tooth prep sites, the latest generation of nanotechnology composite resin (G-ænial Sculpt, GC America) was used. A sequence of composite resin layering was done to blend the composite resin to the existing tooth and create a polychromatic effect. In restoring tooth No. 10, a thin layer of shade A1 was placed along the lingual aspect to mimic the lingual enamel coloration. Then, as a dentin replacement, an opaque dentin shade (AO2) was placed to assist in blocking out any shine-through of light. Using a freehand sculpting technique, universal shade A1 was sculpted over the opaque dentin composite resin as an enamel replacement. Finally, a translucent layer, AE (Adult Enamel), was blended over the facial cavosurface margin as the final layer to create a natural chameleon effect. In restoring tooth No. 9, a lingual shell using G-ænial Sculpt A1 was first bonded to recreate the proper lingual contour and color (Figure 5). Then color modifiers—gray and opal tints—were artistically painted and light cured to mimic incisal characterizations of the adjacent central incisor.5 Finally, a thin layer of AE was sculpted along the facial surface with an artist’s brush to recreate natural facial contours (Figure 6).
After final light-curing, esthetic contours were refined using aluminum oxide finishing disks, finishing burs, and finishing paste.6,7 Thus, using proper technique and state-of-the-art dental materials, natural color, contour, and finish to mimic natural tooth can be achieved (Figure 7).