INTRODUCTION
Anterior tooth discoloration continues to be an aesthetic concern and a major source of embarrassment for patients. The problem can either be of extrinsic or intrinsic origin, so the clinician must determine this prior to treatment. Extrinsic stains can be removed through oral hygiene and bleaching treatment, as they are stains that build up on the surface of the dentition over time. However, intrinsic stains are internal stains that must be treated through methods that depend on the origin or etiology.1,2
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Figure 1. Severe darkened anterior tooth due to intrinsic staining. |
Depending upon the type and/or cause of the stain involved, the mode of treatment is varied. In cosmetic restorative treatment, porcelain-fused-to-gold (PFG) or all-ceramics (ie, lithium disilicate) are common restorative materials used to correct these aesthetic problems. However, there are other more minimally invasive solutions that can be used to correct unsightly discoloration in the anterior teeth. The use of direct composite resins can be very effective if the occlusion is stable and doesn’t result in high impact forces. However, when occlusal dysfunction/disease is noted, then indirect restorative options are often necessary for long-term restorative success if the occlusal issues cannot be fully addressed before the restorative phase is begun.
Conventional vs Modern Approaches
Conventional treatment of PFG crowns uses an aggressive amount of tooth removal (1.5 mm axial reduction). Porcelain veneers have also been effective in correcting this problem; however, to fully masque out underlying dark tooth structure, an opaque lining is usually required3 (Figure 1). Regardless, porcelain veneers are a good method of treatment as there is less tooth reduction in the preparation design (0.7 to 1.0 mm of axial reduction) than that of a full-crown preparation.
The reason for treatment with full crowns is to completely cover existing dark intrinsic stains in the teeth. However, with the conventional full-crown treatment option, natural tooth illumination cannot be attained. The ability to reflect, refract, and absorb light is extremely important to achieve natural aesthetics. Therefore, an alternative approach using a direct/indirect technique would thus achieve the best of both worlds: minimal invasive preparation and natural aesthetic results.
Preparation Protocol
In treating the darkened anterior teeth conservatively, a uniform 0.7-mm preparation is done first (prep guide bur 828.030 [Komet USA]) along the facial, proximal, and incisal areas. For darkened teeth, 0.7-mm thickness is the minimum depth needed for a ceramist to effectively increase the visual value and hue.4,5 After the initial prep of 0.7 mm has been completed, the clinician must evaluate the severity of the darkened tooth. If it is still very chromatic, then an additional 0.3 mm of preparation depth along the dark chromatic areas (prep guide bur 828.022 [Komet USA]) is done to create additional space to internally masque out the darkened area with a direct opaque liner. By using an internal opaque liner to lighten a dark stumpf (prepared dentin) shade, internal (lab placed) opaquers in the porcelain veneers are not needed 4,6 (Figure 2).
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| Figure 2. Dentin adhesive resin placed prior to masquing the dark stain with opacious dentin composite resin. | Figure 3. After the bonding of the opacious dentin shade, the porcelain veneer preparations were finalized. |
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| Figure 4. The final result was more aesthetic because a non-opaque veneer was used to correct this problem. | Figure 5. A 65-year-old male presented with severe intrinsic tetracycline staining. |
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| Figure 6. A 0.7-mm prep guide bur (828.030 [Komet USA]) was used to create a uniform depth preparation. | Figure 7. A 0.3-mm prep guide bur was used to remove the more chromatic stains and to create additional space for the masquing dentin shade procedure. |
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| Figure 8. One of the latest generation dentin adhesives (All-Bond Universal [BISCO Dental Products]) was placed onto the 0.3-mm prepped surface and fully light cured. | Figure 9. G-ænial Universal Injectible (shade AO-2) (GC America) was used to masque the chromatic dark prepped area and to create a uniform internal shade. |
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| Figure 10. After blocking out the dark intrinsic stains, the result was a uniform internal shade for natural-color porcelain veneers. | Figure 11. Because the dark intrinsic color was neutralized, a natural result with porcelain veneers could be achieved. |
An opacious dentin shade nano-hybrid composite resin (G-ænial Sculpt AO-2 [GC America]) can neutralize the dark internal shade effectively. The opacious dentin shades are very similar to natural dentin in color. With a 0.3-mm thickness of this material, the clinician is able to easily and effectively masque out the darker tooth structure and blend the composite layer to the natural coloration of the surrounding teeth (Figure 3). Because the internal stumpf shade is now a much more natural color, a naturally shaded porcelain veneer can be fabricated in the lab without an opaque liner (Figure 4).
CASE REPORT
A 65-year-old male presented with severe tetracycline intrinsic stains (Figure 5). He wanted a brighter smile but stated that he did not want his teeth to “look fake.” He also expressed a desire to avoid full crowns. Due to the presence of deep intrinsic stains, a direct/indirect method was recommended to the patient because it provides a natural, aesthetic appearance using conservative preparation techniques.
Clinical Protocol
To prepare the teeth, a 0.7-mm uniform reduction was required (Figure 6). Then, only along the dark chromatic facial areas, 0.3 mm were additionally prepared (Figure 7). Along this area, opacious dentin composite resin would be directly placed and sculpted to block out the dark intrinsic stain.
A universal adhesive (All-Bond Universal [BISCO Dental Products]) was placed onto the prepped teeth and fully light cured (Figure 8). Next, the opacious dentin composite resin (G-ænial Universal Injectable AO-2 [GC America]) was placed and sculpted only along the facial axial surface to block the dark intrinsic stains (Figure 9). The teeth preparations were then finished with tapered chamfer diamond burs (6844.014 [Komet USA]) (Figure 10), and, once completed, the final impression was taken (Impregum [3M]). Next, temporary prototypes were created using a putty stent of the original diagnostic wax-up of the case. The impressions and other required treatment records were then sent to the dental laboratory team for the fabrication of the all-ceramic veneers.
At the second appointment, the temporaries were removed, and the feldspathic porcelain veneers were tried-in to determine if additional color modification would be needed to increase the color brightness. Using a variety of try-in pastes (Choice 2 Try-In Paste Kit [BISCO Dental Products]) helped the patient determine the desired final shade of the porcelain veneers.
Once the fit and color were verified and approved, the porcelain veneers were cleaned, etched, and silanated (Bis-Silane [BISCO Dental Products]), and then placed under a lightbox to prevent premature curing from the ambient operatory lighting. The prepared teeth were then cleaned with a mixture of flour pumice and chlorohexidine gluconate (Cavity Cleanser [BISCO Dental Products]). Next, using a selective-etch technique, 35% phosphoric acid (Select HV Etch with BAC [BISCO Dental Products]) was used for 30 seconds on the enamel. Then All Bond-Universal was applied to the prepared tooth structure, air thinned, and light cured. A luting resin (Choice 2 Milky Bright Veneer luting resin [BISCO Dental Products]) was used to bond in the porcelain veneers to achieve a bright overall effect. Final bonding was accomplished by light curing (Sapphire Plasma Arc Curing Light [DenMat]) the porcelain veneers along the facial and lingual surfaces.
The final finish of the restorations was accomplished with a series of finishing diamond burs (Porcelain Finishing Kit [Komet USA]) and polishers. Finally, a microdiamond polishing paste (Diamond Polish [Ultradent Products]) with a polishing wheel gave the new ceramic restorations a very natural luster (Figure 11).
CLOSING COMMENTS
Intrinsically stained darkened anterior teeth are a formidable aesthetic challenge. However, technological advances in material science allow an innovative direct/indirect technique, as outlined and described herein, to produce a highly aesthetic result with minimally invasive tooth preparations.
References
- Giunta JL, Tsamtsouris A. Stains and discolorations of teeth: review and case reports. J Pedod. 1978;2:175-182.
- Parkins FM, Furnish G, Bernstein M. Minocycline use discolors teeth. J Am Dent Assoc. 1992;123:87-89.
- Cheek CC, Heymann HO. Dental and oral discolorations associated with minocycline and other tetracycline analogs. J Esthet Dent. 1999;11:43-48.
- Okuda WH. Using a modified subopaquing technique to treat highly discolored dentition. J Am Dent Assoc. 2000;131:945-950.
- Yamada K. Porcelain laminate veneers for discolored teeth using complementary colors. Int J Prosthodont. 1993;6:242-247.
- Nixon RL. The Chairside Manual for Porcelain Bonding. Wilmington, DE: BV Videographics; 1987.
Dr. Okuda practices in Honolulu, Hawaii. He is a past national president (2002 to 2003), board-accredited member, and board-accredited Fellow of the American Academy of Cosmetic Dentistry (AACD). He has been an international speaker for more than 22 years and has authored numerous articles on cosmetic and restorative dentistry topics. He also is a Fellow of both the International College of Dentists and International Congress of Oral Implantologists. He is the aesthetic dentistry expert for the National Dental Advisory Board of the AGD and the aesthetic columnist for General Dentistry. Since 2007, Dr. Okuda has been listed in Dentistry Today’s Leaders in CE. He is the cofounder of the Give Back a Smile program, the national charitable foundation of the AACD, which helps survivors of domestic violence throughout the nation to restore their smiles and lives. Dr. Okuda is also the founder of Pan Pacific Dental Academy (panpacdental.com) where he and his dental team teach young dentists about predictable clinical techniques, powerful practice management, and proven business development skills to develop a successful boutique dental practice. He can be reached at okudacosmeticdentistry.com or on Facebook at @drwynnokuda.
Disclosure: Dr. Okuda reports no disclosures.
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