Conservatism and Simplicity: Aesthetic Restoration of the Single Maxillary Central Incisor

The dental literature today suggests that aesthetic dentists are choosing to exercise greater and greater conservative creativity in the manner in which they treat those patients who present requesting aesthetic enhancement of their smile.^1-3 A once overabundant “prep and place” mentality is giving way to more insightful thought as to how best to achieve the patient’s goals, accounting for cost, conservatism, and future needs. Clinicians are asking themselves, for example, if aesthetics can be improved with bleaching and bonding³ rather than with extensive preparations and placement of all-porcelain restorations.

Unquestionably, situations exist that suggest the need for comprehensive or more aggressive treatment with indirect restorations.^4,5 In those cases, it is generally accepted that crowns, veneers, or other indirect restorations are the most appropriate choices to correct aesthetic concerns, re-establish occlusal harmony, and return the patient to appropriate function, based on findings from thorough examinations.

However, whether it is a result of improvements that manufacturers have made to the composition and optical properties of direct composites^1,6 or it is based upon a conscientious realization that treatment today impacts the possibilities for tomorrow,^2,3,5 the placement of direct composite in the highly visible anterior zone is increasingly being recognized as a means for providing minimally invasive, exceptionally artistic restorations. In this author’s opinion, as in the case presented later in this article, when combined with dentist-monitored vital tooth bleaching,^3,7,8 the conservative and aesthetic treatment potential of direct composites is tremendous.

A number of noteworthy dental artists have helped to elevate the composite placement techniques used for creating direct anterior composite restorations, including Terry,⁶ Fahl,9 Jackson,1 and others.¹⁰ Their work and composite-layering techniques—which visibly result in lifelike and highly aesthetic direct composite restorations—are based on a clear understanding of tooth morphology, color (ie, hue, chroma, value, translucency), structure (ie, enamel and dentin), and the manner in which all 3 interact to affect the appearance of natural teeth.^1,6 The often multiple composite shade and layering techniques they employ are also based on an understanding of the characteristics of available materials in order to apply them in a manner that will mimic the appearance of natural dentition.^1,2,11

Although it is essential that today’s dentists understand the subtle nuances of composite materials and the manner in which to place different shades of composite to achieve a natural-looking restoration,^1,2,6 particularly to restore a highly characterized tooth11 (or adjacent tooth), it is also necessary to be able to place predictable, aesthetic, and durable composite resin restorations in the anterior region according to more simplified techniques. Specifically, clinicians have sought composite material systems that would enable placement of a single material that demonstrates chameleon effects similar to what occurs in natural teeth, without the need to follow technique-sensitive layering or placement protocol.²

The following describes the case of a 22-year-old female patient who presented with a previously restored class IV fracture on the right maxillary central incisor. The simplicity of the techniques used associated with the placement of a new nanohybrid composite material are demonstrated to show the predictability and aesthetic success that can be achieved for a single restoration in the highly visible anterior dentition.

CASE PRESENTATION 

Figure 1. Preoperative view of the patient. Note cross-bite on the left side and anterior end-to-end occlusion.	Figure 2. Close-up preoperative view of the patient’s maxillary central incisors. Tooth No. 8 had been previously restored with composite to correct a class IV fracture.

Upon presentation, the patient underwent a complete examination that included radiographs and photographs as well as a visual assessment to evaluate the occlusion and morphologic, histologic, and optical characteristics of the patient’s dentition. No pathologies were found, although a cross-bite on the left side was noted along with an anterior end-to-end occlusion (Figure 1). The patient’s chief complaints were the discoloration of her dentition, including the previously placed restoration on tooth No. 8 to repair a class IV fracture (Figure 2).

TREATMENT PLANNING

Restorative alternatives were discussed with the patient, keeping in mind the conservative nature of the treatments that could be performed to address her chief complaint: tooth discoloration. Based on her condition, generally good oral health, lack of pathologies, and the options presented, the treatment plan developed would include the following: in-office power bleaching (BriteSmile), followed by at-home, dentist-monitored 9% hydrogen peroxide vital bleaching (Tres White, Ultradent Products), and the subsequent replacement of the direct composite restoration on tooth No.8 using a new micromatrix restorative (TPH3, DENTSPLY Caulk). The patient accepted this treatment plan.

RESTORATIVE MATERIAL

The use of nanotechnology (ie, nanoparticles and proprietary glasses) in light-cured composites was introduced in recent years in the form of several available composites, including Esthet-X (DENTSPLY Caulk), which features an exclusive micromatrix application of this technology. In particular, the micromatrix application—now also available in the new TPH₃ restorative—incorporates the use of proprietary resin and glass. Optical properties are achieved through precise milling of glass particles, and strength is achieved through the size, shape, and distribution of these particles. The resin used in the TPH₃ restorative, which is based on the same clinically proven resin matrix that has been used for more than 11 years, features an enhanced, patented photoinitiator for an efficient conversion ratio and extended ambient working time. Additionally, the same fillers and resins are applied to all shades and opacities in the restorative system to ensure consistent physical properties. TPH₃ restorative is available in a total of 26 shades, including 22 body (dentin) shades, 3 translucent enamel shades, and 1 opaque dentin shade. TPH₃ material has a nonsticky consistency without rebounding or pulling back. It is directionally easy to control and feathers to margins.

TOOTH WHITENING 

Figure 3. Among the patient’s chief complaints was the discoloration of her dentition. Her prebleaching shade was taken and found to be A3.

The pre-bleaching shade of the patient’s dentition was taken (Figure 3) and found to be A3. The patient was appointed and then returned for in-office power bleaching using the BriteSmile system, after which she was given the take-home bleaching kit to use as prescribed. Because the selected take-home kit does not require a custom-fitted tray, no impressions or models were necessary prior to dispensing the whitening kit. The patient was instructed to use the whitening kit as directed for 7 days.

	Figure 4. Following in-office power bleaching and a dentist-monitored take-home regimen, the patient’s final preoperative tooth shade was A1.
	Figure 5. As a result of the vital tooth bleaching, much of the tooth shade nuances and idiosyncrasies were removed, making composite shade selection easier using a custom TPH3 shade tab.
	Figure 6. The shade of the patient’s dentition was digitally verified using the Easyshade shade selector.

Two weeks after completing the at-home whitening regimen (Figure 4), the patient returned to the office for replacement of the composite restoration on tooth No. 8. Using a custom-made TPH₃ shade tab, the shade of the patient’s teeth was determined now to be A1 (Figure 5). This shade was verified using a digital spectrophotometer (Easyshade, Vident), which was also used to select the desired composite shade more accurately (Figure 6).

Figure 7. Different shades of the TPH3 composite were previewed on the patient’s dentition in order to help determine the most appropriate shades for use in this case.

Because the whitening procedures successfully removed many of the preoperative shade nuances and color idiosyncrasies of the patient’s dentition, color-matching the composite to the patient’s dentition was greatly simplified. However, composite shades were still previewed on the patient’s dentition (Figure 7) to verify color consistency and “invisibility” with the adjacent natural teeth.

In this case, it was determined that Bleach White TPH₃ composite would be used as the lingual enamel layer to control opacity and prevent shine-through. The A1 dentin-shaded TPH₃ composite would be used to create the body of the restoration, since its inherent chameleon-like qualities—according to the manufacturer—would easily and invisibly blend with the natural tooth structure and surrounding dentition. Clear enamel composite would then be placed over the entire restoration.

Figure 8. A putty stent was made to serve as a volumetric guide during placement of the composite material.	Figure 9. Tooth No. 8 was prepared with a 2-mm-long bevel and a lingual shoulder preparation.

Prior to initiating preparation and composite placement, an impression was taken in order to create a putty stent for use as a volumetric, 3-D guide for placement of the composite (Figure 8).¹² The existing composite restoration was removed, and the tooth was prepared with a 2-mm-long bevel in addition to a 0.5-mm to 1-mm lingual shoulder preparation (Figure 9). Additionally, according to the aesthetic principles of Jackson for class IV restorations, the cavosurface margins were sufficiently prepared to allow the composite resin to conceal the underlying fracture line.¹

ADHESIVE PROTOCOL 

	Figure 10. The putty stent was placed in the patient’s mouth following preparation to verify special reference.
	Figure 11. Tooth No. 8 was etched with a 34% phosphoric acid tooth-conditioning gel.
	Figure 12. An adhesive bonding agent was then applied to the preparation.

After preparation, the putty stent was placed in the patient’s mouth for spatial reference (Figure 10) and removed. Using a 34% phosphoric acid system (Tooth Conditioning Gel, DENTSPLY), the tooth was etched for 15 seconds (Figure 11), thoroughly rinsed, and dried. A single-component bonding agent (Prime and Bond NT, DENTSPLY) was then applied to the preparation for 15 seconds using a light brushing motion (Figure 12), air-thinned for 3 seconds to avoid pooling, and light-cured for 20 seconds.

STEP 1—CONTROL OPACITY WITH THE LINGUAL ENAMEL COMPOSITE LAYER

	Figure 13. The Bleach White TPH3 composite was placed as the lingual enamel layer of the restoration.
	Figure 14. The composite was easily manipulated using a Hollenback No. 6 instrument.
	Figure 15. The putty stent was removed to verify the opacity of the lingual enamel composite.

The buildup of the restoration began by placing the putty stent back into the patient’s mouth, after which a 1-mm thick layer of the selected Bleach White shade of TPH3 composite was placed to form the lingual enamel layer (Figure 13). This lingual enamel layer was easily sculpted into place using a Hollenback No. 6 instrument (HuFriedy, Figure 14), staying clear of all interproximal and incisal edges but running onto and along the bevel. The putty stent was removed to verify opacity (Figure 15), and this layer was light-cured for 20 seconds.

Figure 16. Shade A1 TPH3 dentin body composite was placed, and care was taken to manipulate the composite to create a rippling effect.

With adequate room remaining, shade A1 of the TPH3 dentin body composite was placed in a single, 2-mm increment on the cervical/gingival aspect of the tooth, down along the middle third, but staying shy of full contour to allow for placement of the final translucent layer (Figure 16). Care was taken to manipulate the composite in such a way as to create an internal rippling effect that would allow light to refract and disperse naturally. This layer was light-cured for 20 seconds.

STEP 3—MIMIC NATURAL ENAMEL EFFECTS WITH A SINGLE SHADE AND LAYER 

Figure 17. Following placement and curing of the clear enamel layer, the putty stent was used to verify the full contour of the restoration on tooth No. 8.

The clear enamel TPH₃ composite was placed along the full contour of the restoration to stabilize the color of the restoration and create the appearance of high luminosity. This layer was light-cured for 20 seconds, after which the putty stent was placed back in the patient’s mouth to evaluate the full contour of the restoration (Figure 17). The putty stent was then removed, and transenamel light curing was performed for 60 seconds from multiple aspects to ensure a complete cure.

	Figure 18. The incisal edges of the restoration were finished using extra-thin polishing and finishing discs.
	Figure 19. The restoration was polished using a foam cup and Prisma polishing paste.
	Figure 20. Final postoperative close-up view of the vitally aesthetic direct composite restoration on tooth No. 8.

To finish the restoration, extrafine finishing and polishing discs (3M ESPE) were used along the incisal edge (Figure 18). Polishing was completed using polishers that impart a tooth-like luster and reflectivity to the restoration (Prisma Gloss, DENTSPLY, Figure 19). When complete, the new TPH₃ direct composite restoration invisibly matched the patient’s natural tooth structure and adjacent dentition (Figure 20).

CONCLUSION

At a time when dental professionals desire more simplistic and conservative approaches to restoring a patient’s smile aesthetically, they simultaneously demand predictability and durability from the techniques and materials they choose. This article has described a case in which a new direct composite material and associated technique were used to create a conservative and aesthetic restoration in the anterior zone that defies detection.

References

1. Jackson RD. Understanding the characteristics of naturally shaded composite resins. Pract Proced Aesthet Dent. 2003;15:577-585.

2. Milnar FJ. Immediate, direct rehabilitation of fractured maxillary central incisors in the pediatric patient. Dent Today. Apr 2004;23:98-103.

3. Haywood VB, Pohjola R. Bleaching and esthetic bonding of tetracycline-stained teeth. Contemp Esthet Restor Pract. 2004;8:16-23.

4. Weinstein AR. Esthetic applications of restorative materials and techniques in the anterior dentition. Dent Clin North Am. 1993;37:391-409.

5. Friedman MJ. Porcelain veneer restorations: a clinician’s opinion about a disturbing trend. J Esthet Restor Dent. 2001;13:318-327.

6. Terry DA, Leinfelder KF. An integration of composite resin with natural tooth structure: the Class IV restoration. Pract Proced Aesthet Dent. 2004;16:235-242.

7. Haywood VB, Robinson FG. Vital tooth bleaching with Nightguard vital bleaching. Curr Opin Cosmet Dent. 1997;4:45-52.

8. McCaslin AJ, Haywood VB, Potter BJ, et al. Assessing dentin color changes from nightguard vital bleaching. J Am Dent Assoc. 1999;130:1485-1490.

9. Fahl N Jr. Achieving ultimate anterior esthetics with a new microhybrid composite. Compend Contin Educ Dent Suppl. 2000;26:4-13.

10. Teel TT. Using a combination of flowable and direct composites for the conservative restoration of the single maxillary central incisor. Contemp Esthet Restor Pract. 2004;8:18-26.

11. Chalifoux PR. Composite tints: mixing composite materials to alter color and techniques to simulate hypocalcification and craze lines. Compend Contin Educ Dent. 2004;25:583-591.

12. Behle C. Placement of direct composite veneers utilizing a silicone buildup guide and intraoral mock-up. Pract Periodontics Aesthet Dent. 2000;12:259-266.

Dr. Milnar is a graduate of the University of Minnesota School of Dentistry. An accredited member of the American Academy of Cosmetic Dentistry (AACD) and a board examiner for accreditation, he is also a developer/evaluator of new materials for several dental product manufacturers and medical device and biomedical companies. He is a past editor for the AACD Academy Connection newsletter and maintains a full-time practice emphasizing appearance-related dentistry in St. Paul, Minn. In addition to authoring numerous articles on the techniques associated with the placement of today’s direct composite restoratives, he lectures internationally and is a cofounder of the Minnesota Academy of Cosmetic Dentistry. He can be reached by phone at (651) 645-6111, by fax at (651) 645-6014, or by e-mail to frank@milnardds.com. Disclosure: Dr. Milnar is a consultant for Dentsply in terms of material development and evaluation and has also received financial support.