layering materials to achieve an undetectable transition between natural tooth … · 2018. 3....

Winter 2018 • Volume 33 • Number 4 18

ACCREDITATION ESSENTIALS

Dawn Wehking, DDS

Layering Materials to Achieve an Undetectable Transition Between Natural Tooth and Composite

AbstractA Class IV composite is a conservative and successful restoration that can be done predictably with proper clinical training. This type of restoration is an exciting test of skill, combining knowledge of materials, artistry, and function. While it helps to have an artistic eye, a successful restoration can be achieved by learning the methodology behind composite layering. By following a precise layering protocol and learning how to replicate surface texture, clinicians can create a seamless transition from natural tooth to restoration. Understanding these layering concepts allows the clinician complete control over the restoration’s final appearance.

Key Words: Class IV, layering, conservative, characterization, Case Type IV

19 Journal of Cosmetic Dentistry

Becoming proficient at direct layering techniques allows the clinician to create beautiful and functional restorations.

Wehking

Introduction Class IV fractures are frequently seen in general dental practices. To some clinicians it may seem quicker, easier, and more cost-effective to prepare for an indirect resto-ration. While indirect restorations can have excellent es-thetics, they require additional tooth preparation and im-peccable laboratory collaboration.1 Becoming proficient at direct layering techniques allows the clinician to create beautiful and functional restorations.

Case Description

Patient Complaint and History A 46-year-old female in excellent physical health was unhappy with the discolored composite restoration on tooth #8 (Figs 1 & 2). This restoration had been replaced twice since a childhood trauma. Treatment options dis-cussed included no treatment, composite, or a porcelain restoration. She chose to replace the composite restora-tion to remain conservative and as minimally invasive as possible.

FindingsThe discolored restoration extended through dentin and enamel. Her excursive patterns caused the restoration to wear against #26, so the tooth appeared shorter than #9 (Fig 3). Once the patient decided to proceed with treat-ment, the 12 “before” photographs required for AACD Accreditation were taken.2 As a patient of record, the patient had previously been evaluated for temporoman-dibular joint health, masticatory muscle function, peri-odontal health, tooth condition, and esthetics. An oral cancer exam was also completed and a full mouth series of radiographs was taken with no pathology noted.

Figure 1: Preoperative natural smile, frontal view (1:2), showing thediscolored restoration on #8.

Figure 2: Preoperative retracted frontal view (1:2). Tooth #8 is shorter than #9 and #26 is longer than the other lower incisors, contributing to wear of the existing restoration during excursive forces.

Figure 3: Preoperative retracted maxillary anterior view (1:1), emphasizing the discolored restoration and asymmetry.



Shade SelectionBefore preparing the tooth, shade selection was per-formed using a customized shade guide (Estelite Omega, Tokuyama; Encinitas, CA) and a D7000 camera (Nikon; Melville, NY). A customized shade guide allows for ac-curate visualization of hue and value, whereas a typical shade guide is not made of the actual composite resin and therefore may show optical properties different from the actual composite.3 There is also a varying degree of shade-matching results between brands of shade guides.4 The left central incisor was used as a reference for color and surface texture.

Mock-UpA composite mock-up was completed intraorally, adding composite to the existing restoration to create ideal length and lingual contour. A lingual putty matrix was then made (Genie VPS Impression Material, SultanHealthcare; York, PA). A sample selection of composite dentin and enamel shades were applied (without adhesive) in order to devel-op a plan for shades and characterization.

Knowing how to layer composite requires an under-standing of the internal layers of a natural tooth. A natu-ral tooth has a more opacious center (dentin) and a more translucent outer layer (enamel).3 Dentin is approximate-ly 20% more opaque than enamel and provides most of the tooth’s hue.5, 6 Knowing this, it is necessary to find a brand of composite that allows at least those two differ-ent opacities. The restoration will have a natural appear-ance when the material is able to reflect and scatter light similar to natural dentin and enamel.7

Treatment Preparation: The discolored composite was removed and the remaining tooth structure was prepared using a star-burst bevel and a lingual chamfer. Use of the starburst bevel, which varies in length, depth, and width, enables the composite to almost “disappear.”8 A clear mylar strip was placed to separate the adjacent teeth, and the tooth was etched for 20 seconds on the enamel and 15 seconds on the dentin with 37% phosphoric acid. A single-bottle adhesive (Scotchbond Universal, 3M ESPE; St. Paul, MN) was applied and light-cured for 20 seconds.

Preoperative photographs were referenced to repli-cate the adjacent central incisor using Estelite Omega, a supra-nanofilled composite that allows high toughness in functional areas and excellent polishabilty in the es-thetic zone.5 A low-viscosity filled wetting resin (Brush & Sculpt, Cosmedent; Chicago, IL) was used to lubricate the instruments and brushes during the procedure to elimi-nate composite stickiness and pullback. While some cli-nicians use an unfilled resin as a wetting agent (typically their composite adhesive), doing so can incorporate hy-

droxyethyl methacrylate (HEMA) into the restoration and cause discoloration.

Composite layering: The first layer of composite, shade MW, was placed in a very thin layer (less than .3 mm) on the lingual putty matrix extending to the incisal edge. This very thin lingual shelf establishes the facial-incisal line angle to which the other layers will be built.

The next layer—artificial dentin—is the most important step in achieving a seamless restoration. Because the dentin is the most opaque part of the tooth, selecting the correct dentin shade allows the clinician to mask the junction between the natural tooth and the restoration.9 Dentin shade DA2 was extended almost all the way to the incisal edge since the adjacent central did not exhibit much translucency. This layer was carried coronally over the natu-ral dentin until it completely masked the junction between the natural dentin and dentin shade composite. To gauge the space required for the enamel layer, the incisal, middle, and cervical contours were checked against the adjacent central incisor. It is important to make sure that the junction between natural dentin and artificial dentin is completely masked at this point. If a line is visible here, then a line will be visible on the final restoration because the subsequent layers will be more translucent.

Enamel shade EA1 was layered directly over the dentin shade (Fig 4). White modifier (Kerr; Orange, CA) was added to replicate the surface character of the adjacent central incisor. A very thin coat of translucent composite was added as the final layer to seal in the white characterization. Final curing was completed through a layer of glycerin to eliminate the oxygen-inhibited layer.

Reevaluation: After completion of the restoration, #9 had sig-nificantly dehydrated, which made it hard to determine whether the characterization was going to match appropriately.3 The pa-tient returned two days later for reevaluation, after which we added more white characterization. A .014 chamfer diamond bur (Brasseler; Savannah, GA) was used to cut back a thin layer of the incisal/facial, more white tint was added, and a new layer of translucent composite was added (Fig 5).

Occlusion was checked in maximum intercuspation and ex-cursive movements using 90-micron articulating ribbon (Ma-dame Butterfly Silk, Almore; Portland, OR). Tooth #26 was short-ened incisally to make it even with the incisal edge of #25 so that the patient did not bump her new restoration during excursive movements (Fig 6).

Finishing and polishing: Final surface texture and polish was achieved with the UCLA LeSage Anterior Esthetic Restorative Sys-tem (Brasseler). The incisal edge of the facial of the restoration was created by preparing lightly through the layer of white tint and enamel composite. This allowed the dentin shade to show through and recreate the look of the darker worn edge on #9 (Fig 7). During the final polishing process, photography was very helpful in magnifying the image to see the patient’s unique char-acterization and reflection of light.


Wehking

Capturing these details of nature and transferring them to composite was possible because of the optical properties, high strength, and polishability of nanofilled composites.

Figure 4: Restoration before additional characterization was imparted. Note the flatness of the restoration before the addition of white tint.

Figure 5: Postoperative natural smile, frontal view (1:2), showing the completed restoration.

Summary Restoring the patient’s fractured tooth with composite allowed us to conservatively achieve a natural result, mimicking the unique characteristics, translucency, and morphology of her natural dentition. Capturing these details of nature and trans-ferring them to composite was possible because of the optical properties, high strength, and polishability of nanofilled com-posites. The patient was thrilled with her result (Figs 8 & 9).

Figure 6: Postoperative retracted frontal view (1:2), showing enameloplasty of #26 to prevent the patient from wearing down the new restoration during her habitual excursive patterns.

Figure 7: Postoperative retracted maxillary anterior view (1:1), displaying characterization with white tint.



Figure 9: The happy patient and her new smile.

Figure 8: Postoperative natural smile showing surface texture at the incisal edge.

References

1. Dunn J. Direct composite or bonded porcelain: a clinical choice for anterior

aesthetics. J Calif Dental Assoc. 1994 Apr;22(4):73-6, 78.

2. American Academy of Cosmetic Dentistry (AACD). Photographic documenta-

tion and evaluation in cosmetic dentistry: a guide to Accreditation photogra-

phy. Madison (WI): AACD; 2013.

3. Fahl N Jr. Coronal reconstruction of a severely compromised central incisor with

composite resins: a case report. J Cosmetic Dent. 2010 Spring;26(1):92-113.

4. Paravina RD. Performance assessment of dental shade guides. J Dent. 2009;37

Suppl 1:e15-20.

5. Fahl N Jr. A polychromatic composite layering approach for solving a com-

plex Class IV/direct veneer/diastema combination: part II. Pract Proced Aesthet

Dent. 2007 Jan-Feb;19(1):17-22.

6. Okuda W. Minimally invasive dentistry and its impact on esthetic restorative

dentistry. Gen Dent. 2013 Aug;61(5):24-6.

What I learned from Case Type IV

• The first version of the restoration, seen in Figure 4, did not show enough characterization. The restoration was then cut back so that surface characterization could be added.

• The final value is darker than the adjacent central. Err on the side of a lighter value when selecting the dentin shade.

• Take enough time and pay attention when polishing. I wish I had polished #8 a little more to better match #9.

Author’s Observations

Dr. Wehking maintains a practice in Lafayette, Colorado.

Disclosure: The author did not report any disclosures.

7. Bassett J. Conservative restoration of a traumatically involved central inci-

sor. Compend Contin Educ Dent. 2012 Apr;33(4):264-7.

8. Villarroel M, Fahl N, De Sousa AM, De Oliveira OB Jr. Direct esthetic res-

torations based on translucency and opacity of composite restorations. J

Esthet Restor Dent. 2011 Apr;23(2):73-87.

9. Lavigne C. Four products to immediately improve your composite resto-

rations. Spear Digest. Nov 2016. Available from: http://www.speareduca-

tion.com/spear-review/2016/11/four-products-to-immediately-improve-

your-composite-restorations. jCD

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24 Winter 2018 • Volume 33 • Number 4

Case Type IV tests the clinician’s ability to seam-lessly blend and shape composite resin to virtu-

ally become one with the natural tooth. Blending a composite restoration with a natural tooth is not only about the hue selected. Successful completion of this case type requires using composite resin to prepare a Class IV fracture or close a diastema of at least 1 mm. There should also be an emphasis on managing the micro esthetics pertinent to the case.

According to the AACD’s A Guide to Accreditation Cri-teria, “Micro esthetics are those criteria related to the subtle intricacies of shade, texture, translucency, and surface effects that make teeth look like teeth.”1 These intricacies include surface effects, finish, luster, shade selection, and blocking out any trace of the fracture line. In Case Type IV, global smile design principles do not play a major role in the examiners’ evaluations.

Dr. Wehking did well in selecting this case for Ac-creditation submission. Although the patient’s teeth had some subtle surface textures to mimic, there was very little color variation on the contralateral tooth (Fig 1).2

Dr. Wehking chose a nanocomposite for its strength and polishability. As the case history details, after cre-ating a long irregular bevel allowing for a gradual tran-sition from sound tooth structure to the restoration, she used an incremental layering technique when placing the composite material.

Subtle use of a pink opaquer to hide a gray effect in the restoration, followed by a layer of clear translu-cent, as well as carefully planned finishing and polish-ing procedures, led to an excellent final result.3 As seen in the 1:10 photograph, the final restoration’s polish and texture truly mirrored the contralateral central in-cisor (Fig 2).

This case demonstrated clinical excellence. Through thoughtful planning and an intelligent step-by-step approach to conservative composite placement, Dr. Wehking created a restoration that is nearly impercep-tible and suits her patient’s smile very well.

Examiners’ Commentary

The Challenge of Case Type IVBrian J. Gilbert, DDS, AAACD

Blending a composite restoration with a natural tooth is not only about the hue selected.


Gilbert

References

1. American Academy of Cosmetic Dentistry (AACD). A guide to Ac-

creditation criteria. Madison (WI): AACD; 2014.

2. Hartlieb D. Conservative treatment for the adolescent patient. J Cos-

metic Dent. 2014 Spring:30(1):74-90.

3. Hugo B. Esthetics with resin composite: basics and techniques. 1st

ed. Berlin: Quintessence Pub.; 2008. jCD

Figure 2: Postoperative natural smile, full-face frontal view (1:10). The restored tooth ideally matches the contralateral central incisor.

Figure 1: Preoperative natural smile view (1:2). Thoughtful case selection played a role in the restoration’s success.

Dr. Gilbert is an AACD Accredited Member and an AACD

Accreditation Examiner since 1998. He practices in Las

Cruces, New Mexico.

Disclosure: The author did not report any disclosures.

• Criterion 61: Is the margin placement and design appropriate? Are the margins visible? Examiners observed that the margin of the fractured tooth was slightly visible through the restoration.

The examiners passed Dr. Wehking’s Case Type IV. In every case, however, there is always some room for improvement. One such area of agreement between the examiners was noted as follows:

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