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Adding New + Old:
Repairing an existing anterior direct composite restoration

By Robert A. Lowe, DDS
 
  Robert A. Lowe
DDS, FAGD, FICD, FADI, FACD, maintains a private practice in Charlotte, N.C.
A Diplomate of the American Board of Aesthetic Dentistry,
Dr. Lowe lectures internationally and is co-chair
of Advanstar Dental Media’s continuing education advisory board. He can be reached at
704-364-4711 or at
boblowedds@aol.com.
 

One benefit of a direct composite restoration is the ability to repair, or “renew” an existing fractured or marginally defective, but clinically serviceable, restoration. Unlike the restorative interface process that uses conventional alloy or gold metallic restorations that do not “seal” the tooth, with the enamel and dentin adhesive process, areas of the restoration not affected by the “localized” failure remain well sealed clinically.
In addition, the restorative interface procedure does not require removal of all of the old restorative material for the remake.

Nonetheless, it is challenging to successfully add new composite material to existing material. Some clinicians believe that the “oxygen inhibited layer” is required to place composite in increments; others, including Drs. B.I. Suh and L.W. Blank, disagree. Because the polymerization of composite continues many hours after the initial photo curing, increments of composite can be added to previously cured increments
during the build-up phase of the restorative process, as long as the composite surface remains uncontaminated.

However, this does not appear to be true for older composite restorations that have completed the conversion  process and have been contaminated by the oral environment. This article will present a technique for repairing such an older composite restoration—a disto-incisal fracture of an existing direct composite veneer.

The clinical case Determine shade, acid-etch The patient presented with a disto-incisal fracture of a recently
placed direct composite veneer (Figure 1). It is important to remember the “restorative formula” (the shades
selected and their order of placement) from the patient’s chart when multiple shades and/or opacities are used. If this information is not available, use the appropriate shade guide to narrow the shade selection,
and then extrude a small amount of the actual composite to evaluate the color. In this case, the fracture occurred in the enamel (transparent) portion of the build up, so the dentin shade was not needed in the repair of the area. After verification of shade selection, the fractured area is resurfaced using a micro-abrader with 50-micron aluminum oxide particles (Figure 2). This creates micro-mechanical retention, increases surface energy to help wet the surface, and removes unsuitable contaminated material (Figure 3).

Next, the area is etched with 37% phosphoric acid for 15 seconds (Figure 4), then is thoroughly rinsed and air-dried, to thereby ensure thorough decontamination of the existing composite surface and to etch any adjacent enamel and dentin surfaces.

Note: A traditional dentin adhesive can be placed on any enamel and dentin surfaces after first rewetting with a desensitizer, such as AcquaSeal (AcquaMed Technologies). Then, light cure the area.
 
 

[1] A preoperative view from the facial aspect shows a patient with a direct composite veneer that incurred a fracture of the disto-incisal corner. [2] The fractured area is abraded using a micro-etcher and 50-micron aluminum oxide particles. If micro-abrasion is not available, it is recommended to use a coarse diamond rotary instrument and bevel back the fractured area to fresh composite surface. [3] The fractured area is pictured after micro-abrasion. [4] Acid-etch solution (37% phosphoric acid) is placed over the roughened surface for 15 seconds, thoroughly rinsed, then air-dried. This helps ensure a clean surface for bonding that is free from surface contamination.
 

Bonding the new composite

The area of composite-to-composite bonding continues to be a challenge for clinicians using standard dentin bonding adhesive resins. For resin-to-resin, bonding traditionally has been “mechanical only” and really has acted as only a “wetting agent.” CompositRestore (All Dental ProdX), pictured on page 122, is a material that penetrates the old composite matrix and locks onto uncured double bonds (10% to 15% of the double bonds remain uncured (unused during the conversion process) after initial composite placement. When the new composite is added, it can chemically attach to the uncured double bonds, again creating mechanical and chemical retention of the added material. CompositRestore is used to treat the composite surface that will receive the additional restorative material. CompositeRestore is brushed in for 30 seconds (Figure 5) prior to light curing (Figure 6).
 
  [5] Composite primer (CompositRestore: All Dental ProdX) is
brushed into the roughened composite surface for a full 30 seconds. 		[6] The composite primer is light cured for 10 seconds using an LED curing light, or for 20 seconds using a halogen curing light.
 

[7] An incisal shade of composite (Premise: Kerr Dental) is placed on the area to be restored. [8] A CompoRoller (KerrHawe SA) is used to evenly distribute the composite material over the tooth surface. The nonstick disposable tips ensure even thickness with minimal manipulation of the composite material. [9] The fractured area is shown after the addition of new composite, and prior to light curing.

[10] The increment of newly added composite is light cured for 30 seconds.
[11] An 8-fluted carbide composite finishing bur (TDF 9: Axis Dental) is used to shape and contour the newly added material and blend it seamlessly into the existing restoration. [12] Flexible discs (OptiDiscs: KerrHawe SA) are used, making sure that they are rotating from new composite material toward the old composite material to further refine the marginal interface between the two materials.

Placement, finishing, polishing

After light curing is completed, the appropriate shade of composite is placed over the fractured area (Premise: Kerr Dental) (Figure 7), and is spread uniformly over the affected area in both horizontal and vertical directions using a CompoRoller (KerrHawe SA) (Figures 8 and 9). After light curing (Figure 10), an 8-fluted carbide finishing bur (TDF 9: Axis Dental) is used to blend the added composite material evenly with the existing body of composite (Figure 11).

Note: Make sure the carbide instrument is rotating from the newly added restorative material toward the older material. This will help eliminate a visible margin transition.

Flexible polishing discs (OptiDiscs: KerrHawe SA) (Figure 12) are used to accentuate proximal facial line angles and further blend the marginal area into the existing old composite. Next, rubber composite polishing abrasives (KerrHawe SA) (Figures 13 and 14) are used to polish both composite increments simultaneously.

Note: Again, it is important to make sure these abrasive polishers are rotating in the correct direction—from the new composite material toward the older, existing composite material.

For the final polishing step, a composite polishing brush (Occlubrush: Kerr Dental) (Figure 15), impregnated with a composite polishing medium, is used. Note: This brush can be used wet or dry.

Lastly, completely air-dry and brush on a coat of surface sealer (Figure 16), such as QuikGlaze (All Dental ProdX). (Product is pictured above, far right). Surface sealers fill any microscopic imperfections left from the polishing procedure in the marginal areas, and make a seamless transition visibly and by feel between the added composite and the old restorative material. The surface sealant is light cured (Figure 17).

Figures 18 and 19 show the final repaired result. An invisible composite repair has been successfully completed, retaining the esthetics of the original restoration while simultaneously creating a predictably strong bond between the new composite and the old restoration.

 

[18] A 2X facial view of the completed repair of the direct composite veneer.
[19] A 1X view of the completed restoration. Note the seamless blend of the newly added composite material with the existing restoration.
 

[13] A medium-grit rubber composite polisher (KerrHawe SA) is used to smooth and polish the newly placed composite increment. [14] A fine polishing point (KerrHawe SA) is used to create high luster over the entire restorative surface. [15] A polishing brush (Occlubrush: Kerr Dental) completes the polishing process. A high degree of luster is achieved without sacrificing natural surface texture. [16] A surface sealant (QuikGlaze: All Dental ProdX) is brushed on the entire surface of the restoration. [17] The sealant is light cured for 30 seconds.