Periodically, every general dentist encounters clinical situations that can increase his or her stress level when trying to restore the issue. This article will present and discuss several common restorative challenges and offer clinical tips that will assist in achieving better results with less stress.
CROWN ACCESS REPAIR
Crowns may sometimes require repair to seal the holes created by gaining endodontic access. In these cases, patient finances may dictate that the restoration be repaired in lieu of replacement. Of course, the repair is done only if the restoration has acceptable marginal and functional integrity. These repairs can be an aesthetic challenge, either initially or long-term. The predominate materials used today for crowns are either all-ceramic or PFM, with few all-metal crowns currently being placed. The type of dental material that the crown is fabricated from will dictate minor modifications in how the repair is to be performed. Retention is important, and undercutting the endodontic access opening is essential to ensure that the repair remains in place. A 330, or inverted cone carbide bur or diamond, is utilized to undermine the access opening 0.5 mm circumferentially and to a depth across the access opening of at least 2.0 mm. Insufficient thickness of composite will result in failure of the resin under function and early loss.
All-ceramic or PFM full-coverage restorations with endodontic access openings in need of repair may be treated similarly to each other. A diamond is used to place a slight bevel around the ceramic surface of the access opening that is 1.0 mm wide. This will increase the bondable surface of the ceramic, providing a better seal and less leakage and stain potential at the margin of the restoration to be placed. Roughening the ceramic also improves the bond strength to the ceramic material and can be accomplished using a fine diamond bur in a high-speed handpiece or with air abrasion (AeroEtcher Intraoral Blaster [Parkell] or AquaCare [Velopex International]). Once the site is prepared and the exterior margin has been roughened, an appropriate adhesive needs to be applied that will bond with the crown irrespective of the restorative material makeup. Traditional adhesives used for bonding have excellent bond strengths to tooth structure but do not adhere well to metals and ceramics. The author’s preference is to use a C&B-Metabond Quick! kit (Parkell). This adhesive is a 4-META-based, noneugenol, self-curing adhesive resin cement that is designed to provide ultrahigh bond strength to a wide range of dental materials.
Clinical Protocol
The author’s clinical protocol for this technique is as follows: The green Dentin Activator in the C&B-Metabond Quick! kit is applied to the dentin within the endodontic access for 10 seconds, then rinsed off and air-dried. Ea-Z-y Primer (Parkell) is then applied to the ceramic surface, irrespective of the type of ceramic (including zirconia), to improve adhesion. Next, the clear powder provided in the kit is dispensed into one well of the dish. The clear powder delivers good aesthetics when used with all-ceramic crowns (Figures 1 to 3). The opaque powder is best for PFM crowns (Figures 4 to 6) when masking of the metal is required. In a separate well of the mixing dish, 4 drops of Quick Base are dispensed and one drop of the Universal Catalyst is added. Using a “salt and pepper” or “brush dip” technique (also referred to as the Neelon technique), the brush is wetted in the liquid and then touched to the powder and applied to the deepest portion of the preparation in the crown, being certain to coat all surfaces. The adhesive is built up, coating the access margins. Next, an appropriate composite resin of choice is placed into the access opening; then the resin is shaped and light cured. Finally, the restorative repair of the access opening is finished and polished.
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| Figure 1. All-ceramic crown, with an endodontic access opening that required a repair, seen here after air abrasion (AeroEtcher Intraoral Blaster [Parkell] or AquaCare [Velopex International]) was done. | Figure 2. The clear powder, provided in the C&B-Metabond Quick! kit (Parkell), is mixed and applied to the internal surface of the access in the crown, then allowed to self-cure. |
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| Figure 3. Remainder of the access was filled with composite resin (EPIC-AP Composite [Parkell]), then contoured and light cured, providing an aesthetic repair of the crown. |
Perforations in a crown’s surface, either as a result of occlusal adjustment or patient wear, can be repaired in a similar manner. These restoration repairs, as they are most often needed on areas of the crown that contact the opposing dentition, require a greater bevel of the crown margins to ensure good long-term retention.
CONTOUR ALTERATIONS TO ELIMINATE FOOD TRAPS
In the posterior dentition, food traps may occur due to mesial tipping of the tooth, the loss of some interpoximal hard or soft tissue, or a combination of these 2 processes. Frequently, in these situations, the contact is adequate between the teeth but the space gingival to the contact is too large. This can become problematic to the patient as food can easily become trapped in the space under the contact, leading to interproximal caries and/or periodontal issues. A crown can be placed to fill that embrasure area, but that may not be possible for the patient from a financial standpoint. In other cases, the tooth may have minimal restorative material present, requiring the sacrifice of healthy tooth structure to eliminate the space. Recontouring the proximal of the tooth provides a simple and more cost-effective solution.
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| Figure 4. Endodontic access through a PFM crown requiring repair to seal the access. | Figure 5. Opaque C&B-Metabond Quick! (Parkell) has been mixed and applied through the access opening to seal the floor following endodontic treatment and to cover the metal/ceramic around the access opening. |
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| Figure 6. Repair of the access opening has been completed via the placement of EPIC-AP Composite to restore and seal the crown. |
Clinical Protocol
The author’s clinical protocol for this technique is as follows: Local anesthetic is administered into the papilla to prevent potential bleeding during treatment that could affect the placement of the adhesive and composite resins. If the tooth has an existing proximal-occlusal filling, it is removed. When the marginal ridge is intact, it is advised to use a modified technique to preserve the marginal ridge. Posterior teeth with intact marginal ridges have better longevity than those missing this tooth structure. In these cases, a fine diamond is used to roughen the proximal surface apical to the contact area along with a portion of the buccal and lingual surfaces. A precurved matrix affixed to a wedge (FenderMate [Directa Dental]) is placed interproximally. This is done with the wedge portion positioned as far apically as possible on the side of the papilla of the tooth being treated. A thin, flat-bladed composite placement instrument (4 Goldstein Flexi-Thin [Hu-Friedy] or the Comp-Flex 4 [Zoll Instruments]) is then utilized to keep the wedge and its metal matrix against the papilla and the adjacent tooth. Next, a 37% acid etchant gel is injected into the proximal area and across the buccal and lingual surfaces, and then rinsed after 15 seconds and air dried. Brush&Bond Universal (Parkell) adhesive is then applied and light-cured from both the buccal and lingual directions to ensure that all the adhesive is fully cured. Next, a dual-cure resin (such as HyperFIL [Parkell] or Encore D/C [Centrix]) is injected into the buccal by placing the tip through the proximal to the lingual, backfilling the space to the buccal while holding the wedge to the adjacent tooth, and then light-curing it. The wedge is then removed and a new FenderMate with a curve in the opposite direction is inserted into the lingual. Additional resin is injected into the lingual while holding the wedge against the adjacent tooth, and then light cured. Finally, the wedge is removed, and finishing burs are utilized to blend the buccal and lingual surfaces of the resin with the tooth. In addition, a finishing strip may be used to contour the apical aspect of the placed composite, avoiding the contact area to prevent opening it (Figures 7 to 9).
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| Figure 7. The patient presented with pain on the second premolar related to proximal decay involving the pulp and a food trap on the mesial and distal of the implant restoration. | Figure 8. Following endodontic treatment of the second premolar, a rubber dam was removed. A FenderMate (Directa Dental) wedge was inserted between the molar and premolar to act as a matrix. It restored the caries-affected proximal to create a better contour to eliminate the food trap. |
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| Figure 9. Restored and recontoured proximals eliminated the food traps the patient had complained about. |
ANTERIOR CONTOUR FOR CLASS III AND IV DIRECT COMPOSITE RESTORATIONS
Restoring an anterior tooth with a Class III or IV direct composite resin restoration presents challenges developing proximal contours, especially when large embrasure spaces are present. Traditional matrix strips are flat, resulting in a flattening of the proximal gingival area apical to the contact, which creates and/or accentuates a black triangle. Normal anatomy is convex interproximally as the tooth emerges from the gingiva. This development becomes more problematic when the contact is missing or when a diastema needs to be filled.
Clinical Protocol
The author’s clinical protocol for this technique is as follows: When the contact is present, following caries removal, a selective-etch technique minimizes the potential for postoperative sensitivity. A self-etch adhesive (such as Touch&Bond [Parkell] or EveryBond [Centrix]) is applied and then light cured. Next, a clear matrix with precurved progressive curvature (ProxyPal [Directa Dental]) is inserted interproximally, tucking the edge into the gingival sulcus. A small piece of composite is then placed into the gingival aspect between the ProxyPal strip and the tooth. This is adapted to the site while holding the strip against the lingual tooth surface. It is then light cured, thus fixating the strip into the site. The remainder of the preparation is filled with composite resin while using the strip to develop the emergence profile. Finally, the strip is removed and appropriate finishing and polishing steps are performed to complete the restoration (Figures 10 to 14).
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| Figure 10. The patient presented with a complaint of trapping food in the black triangles adjacent to the lateral incisor due to loss of the papilla. | Figure 11. The interproximal placement of a flat Mylar strip demonstrated the flat contour that would result interproximally. |
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| Figure 12. The placement of the progressive curvature ProxyPal (Directa Dental) strip, allowing a more convex proximal curvature. | Figure 13. Following acid-etching and rinsing, the Brush&Bond (Parkell) adhesive is applied, then light cured. |
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| Figure 14. The completed composite restorations (EPIC-AP Composite) were performed to fill the black triangles and missing papilla. |
In cases where a diastema is present or the contact is missing on the prepared tooth, different challenges are posed. A gap between teeth or a missing contact can be built up using the ProxyPal strip, or the process can be simplified using a clear tooth matrix (CoForm [Directa Dental]) that resembles either the right or left half of an anterior tooth. The tooth is prepared for bonding using a total-etch, self-etch, or selective-etch technique. The CoForm is filled with composite resin, introduced interproximally, and adapted to the prepared tooth while keeping the matrix in contact with the adjacent tooth’s proximal surface. It is then light cured. Prior to curing, a thin wedge can be placed at the gingival to help with the adaption of the CoForm to the tooth. The practitioner can utilize this to build up the lingual and proximal areas, leaving the facial unfilled to allow for the later creation of better characterization, if desired/required.
REPAIRING AND/OR ADDING TO AN EXISTING RESTORATION
Sometimes, we may encounter a composite resin restoration that needs a minor repair, such as a chipped marginal ridge or a pit (void) that has developed on the surface of the material. When the margins of the restoration are intact, repair of the restoration may be favored over replacement.
The challenge in repairing composite is developing a bond between the old composite resin and the new composite. When composite is initially placed—which is typically done in incremental layers—the new layer bonds to the air-inhibited layer on the surface of the previous layer of cured composite. Unfortunately, this oxygen-inhibited layer that remains on top of the last layer of composite placed is removed during the finishing and polishing steps. This results in a composite surface that is not as predictable to bond to when attempting a composite repair. Because of this, to achieve a predictable repair, a clinical protocol must be utilized that optimizes both the mechanical retention and the chemical bond strength to the old composite resin.
Clinical Protocol
The author’s clinical protocol for this technique is as follows: The composite surface to be repaired is first roughened using a fine diamond bur. (It should be noted that air abrasion may be used as an alternative to roughening the surface with a diamond bur.) In addition, a bevel is created on the old composite restoration, and mechanical undercuts are placed to further retain and lock the repair to the underlying resin. Silane has been shown to improve the bond strength between old and new composite resin layers. As a result, the author recommends placing it over the area, allowing it to sit for 30 seconds, and then air drying the surface. In the author’s hands, an uncured methacrylate ester monomer (such as Add&Bond [Parkell]) has demonstrated better bonding with composite repairs than other bonding adhesives that were tried. The adhesive is applied to the prepared composite surface and left uncured. Composite is placed over the uncured adhesive, adapted and shaped to the surface, and then light cured for 20 seconds. Finally, finishing and polishing steps are carried out, and the occlusion is checked and adjusted as needed (Figures 15 to 19).
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| Figure 15. Fractured marginal ridge on a recently placed composite restoration. | Figure 16. Following roughening of the fractured resin with a carbide bur, a FenderMate wedge was inserted to provide a contour for the repair to be placed and to protect the adjacent tooth. |
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| Figure 17. The Add & Bond (Parkell) adhesive is applied to the prepared repair area and light cured. | Figure 18. EPIC-AP Composite being added to replace the fractured composite. |
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| Figure 19. The repair of the fractured composite restoration restored the tooth to form and function. |
Along these lines, it can be challenging to add to, or repair, crown and bridge provisionals. The majority of clinicians are now using bis-acryl materials, which differ from the bisphenol A-glycidyl methacrylate (bis-GMA) restorative composite resin materials. Unfortunately, bis-acryl resins will not adhere to previously cured and set composite resins. Additionally, provisional resins tend to be self-curing materials, compounding the challenges in adding to, or repairing, these materials. As with repairing a composite restoration, Add & Bond provides a tenacious bond between bis-acryl provisionals and the bis-GMA resins used for additions and repairs.
CLOSING COMMENTS
Restorative procedures are the “bread and butter” of the majority of general dentistry practices. General dentists all routinely encounter clinical challenges that can increase stress levels, including how to repair endodontic access openings made through full-coverage restorations, what to do with the food trap adjacent to that tipped molar, achieving better emergence contours on anterior fillings, and adding to or repairing composite resin restorations. This article has presented suggestions and techniques for managing these clinical challenges in an effort to decrease stress while, at the same time, achieving better clinical results.
Dr. Kurtzman is in private general practice in Silver Spring, Md. A former assistant clinical professor at the University of Maryland, he has earned Fellowship in the AGD, American Academy of Implant Prosthodontics, American College of Dentists, International Congress of Oral Implantologists (ICOI), Pierre Fauchard Academy, and the Association of Dental Implantology; Masterships in the AGD and ICOI; and Diplomate status in the ICOI and the American Dental Implant Association. He has lectured internationally, and his articles have been published worldwide. He has been listed in Dentistry Today’s Leaders in Continuing Education since 2006. He can be reached via email at dr_kurtzman@maryland-implants.com.
Disclosure: Dr. Kurtzman has received honoraria from Directa Dental in the past.
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