Susan M. McMahon, DMD, AAACD | Lauren Snyder
It is common for patients to seek cosmetic dental treatment to improve their physical appearance and self-esteem. Anterior diastemas or multiple diastemas in particular can cause patients to feel dissatisfied with their smiles. The presence of a diastema can be a negative factor in the attractiveness of a smile. Absent disease, patients with a diastema who desire to enhance the esthetics of their smile are strong candidates for treatment.
There is currently a trend within the dental profession to develop faster, less invasive procedures that are still capable of achieving positive outcomes. Material advancements continue to focus on the development of dentin and enamel replacements that mimic natural tooth structure. Current methods of treating diastema treatment benefit from both these conditions, as this article will demonstrate.
A diastema is a space between adjacent teeth within the same arch. There are multiple causes of diastemas, including transient malocclusion, discrepancy in the tooth size or arch length, genetic factors, or trauma. Currently, there are many techniques available to treat the presence of a diastema, including orthodontics, indirect restorations such as crowns or veneers, and direct restorations using composite resins. Composites make it possible to minimally add material to a tooth without reducing the overall tooth structure. It is seen as a conservative and inexpensive way to enhance one’s smile that can frequently be performed in a single office visit.
One of the main challenges clinicians face during anterior diastema closure is preventing or eliminating a black triangle between the teeth. The term black triangle refers to spaces that appear when gingival tissue, tooth structure, or restorative material do not fill the interproximal embrasure space below the contact point. These spaces appear black because of the darkness of the posterior oral cavity.8 Prevention of black triangles can be challenging during diastema closure due to the architecture of the underlying bone, the shape and alignment of the teeth, and the distance between the contact points and the crest of the bone.
Successful anterior diastema closure using direct composite resin is dependent upon several factors: proper adhesion of material to tooth, development of the emergence profile and natural tooth contours, harmony with surrounding gingival tissues, and color matching and blending. Often little or no tooth preparation is required, especially in cases of disproportionate tooth size, to cosmetically enhance a tooth while maintaining as much healthy tissue as possible. Proper planning, technique, and treatment will result in restorations that simulate the spatial arrangement, relation, and appearance of a patient’s natural surrounding tissues.
To create a natural look while performing diastema closure, it is necessary to match the color and opacity of the tooth. The thickness of the enamel and dentin determine the color of the tooth and are subject to change over time. The proper color and opacity of the restoration used to close the diastema are often accomplished by layering multiple shades and opacities of composite (eg, dentin shades followed by enamel shades). While effective, the process of layering multiple shades and opacities is time consuming and may be technically difficult for some clinicians. Accomplishing successful restorations in a more timely and efficient manner using a simplified material technique is desirable for both the patient and dentist. For this reason, it is advantageous for practitioners to seek the use of a single shade of composite that has excellent blending properties when performing diastema closures.
Since the introduction of dental composite resins nearly 60 years ago, these materials have evolved significantly due to advancements in physical properties leading to decreased wear potential, improved stain resistance, enhanced polishability, and increased color matching. Resin composites are now used in numerous restorative situations; some of the uses include direct restorative materials, cavity liners, pit-and-fissure sealants, inlays, onlays, crowns, and cement for single or multiple tooth prostheses. The desire to provide an efficient, predictable, and less invasive procedure to treat clinical cases has made the use of composite extremely popular in clinical practice.
Besides the basic components of resin and filler, composite resins contain iron oxide pigments and opacifiers designed to create natural tooth color and radiopacity. Historically, each category of composite material has been distinguished by the type of reinforcing fillers and particle sizes it contains. The first composites used were called macrofilled because of the large filler particle size. Although macrofilled composites are extremely strong, they are difficult to polish and it is nearly impossible to maintain their smoothness over time and function. To address this issue, microfilled composites that contained a higher resin-to-filler ratio were developed. Microfilled composites are easier to polish, but they tend to have inferior physical properties such as wear resistance and fracture toughness. Further refinement of filler particle size and shape led to the development of small-particle hybrids and microhybrids. Hybrid composites contain particles of different dimensions that can fit together to reduce the percentage of resin matrix needed. Microhybrid composites provide the strength, polishability, and luster needed for use in both anterior and posterior applications, and are well suited for the correction of anterior diastemas. An even greater refinement in particle size led to the creation of nanohybrids. Nanofillers offer the advantage of increasing the overall filler level due to their small particle sizes and increased surface area of the particles; these materials are also appropriate for anterior diastema closure.
As previously discussed, a common technique for placement of restorations to close anterior diastemas involves layering composites of different shades and opacities. This layering technique is called stratification. Although there are many advantages with the stratification technique, the time and careful eye needed to achieve pleasing results can cause difficulty for some practitioners. A common complaint among clinicians who use this procedure is that it is complex and challenging to make the right color choices. The ability to use one shade of composite that can offer superior color matching and blending would be an ideal solution for many clinicians.
In the case described here, the authors chose TPH Spectra® Universal Composite (DENTSPLY Caulk, www.caulk.com) as an efficient and esthetic option for diastema closure, as this product has a well-balanced refractive index that offers tooth-like appearance and translucency. This creates a chameleon blending effect, allowing the clinician to use a single shade of composite that will be virtually indistinguishable from natural tooth.
A 28-year-old healthy woman expressed dissatisfaction with her smile due to the darkening of her upper right central incisor. Because of her upcoming wedding, she was highly motivated to seek treatment and an esthetic correction. During the initial examination, the clinician noted the presence of the following multiple diastemas: distal to the upper right canine; between the upper right canine and the upper right lateral incisor; between the upper right lateral incisor and the upper right central incisor; between the upper left central incisor and the upper left lateral incisor; and between the upper left lateral incisor and the upper left canine. Figures 1 through 3 show the preoperative appearance of the patient. Additionally, the gingival line was uneven, giving the right lateral incisor and central lateral incisor the appearance of being short and asymmetrical.
Various treatment options were discussed with the patient. The first was indirect porcelain restorations of all the upper incisors with prior gingival sculpting done for symmetry. The other option also included initial sculpting to achieve symmetrical gingival margins, but involved a single indirect porcelain restoration on the upper right central incisor with direct composite bonding to close the diastemas. Both treatment options presented incorporated the use of vital tooth bleaching before definitive treatment. Due to financial reasons, the patient decided on the second treatment option involving direct composite resin placement and a single porcelain crown on tooth No. 8.
After records and photos were taken, at-home vital bleaching was done for 7 days by the patient. At the first restorative appointment, 1.5 mm of free gingiva was removed and contoured on the upper right lateral incisor and the upper right central incisor using electrosurgery (Figure 4 and Figure 5). After 3 weeks, the gingiva was well healed and more symmetrical to the contralateral side. The previous composite restoration on tooth No. 8 was removed; the tooth was then prepared for an esthetic indirect porcelain restoration. The multiple anterior diastemas were closed using a single shade of the low-viscosity version of TPH Spectra composite; it was deemed more appropriate for this case than the high-viscosity formula, which can be used situations in which a stiffer material is desirable.
The teeth were etched using 37% phosphoric acid (Ultra-Etch®, Ultradent Products Inc, www.ultradent.com) for 15 seconds, and then rinsed and lightly air-dried (Figure 6). A total-etch technique was used to enhance the enamel bond strength using Prime&Bond Elect® Universal Dental Adhesive (DENTSPLY Caulk), which can be used with any etching mode; it was applied, air-thinned, and light cured for 10 seconds (Figure 7 and Figure 8). All diastemas were closed using TPH Spectra LV, Shade B1 (Figure 9). Using a single composite shade greatly simplified the diastema closure procedure, which had previously required use of multiple composites, including a dentin shade, enamel shade, and a translucent shade.
The teeth were finished and polished using Sof-Lex™ Finishing and Polishing Discs (3M ESPE, www.3mespe.com), Jiffy® Polishing Cups-Fine (Ultradent), and Jiffy Abrasive Polishing Brushes (Ultradent). A full-arch impression of the upper right central incisor was taken using Aquasil Ultra Xtra (DENTSPLY Caulk). Shade mapping was performed and photographed. Tooth No. 8 was provisionalized with RSVP (Rapid Simplified Veneer Provisionals) (Cosmedent, www.cosmedent.com). The patient returned 2 weeks later for insertion of the single porcelain crown. During the try-in of the upper right central incisor restoration, the mesial contour of the upper left central incisor was deemed inadequate and reshaped using TPH Spectra LV shade B1 (Figure 10). The indirect esthetic restoration of the upper right central incisor was bonded using the Variolink II Esthetic Cementation System (Ivoclar Vivadent, www.ivoclarvivadent.com).
The use of TPH Spectra LV allowed for a bonding procedure that was easily accomplished in about half the time of the traditional layering technique using multiple shades, while offering the desired esthetics. The decreased office time and outstanding final result (Figure 11 through Figure 13) were satisfying for both the clinician and patient.
The increased desire for an esthetically pleasing smile has created a demand for less invasive and more cost-effective procedures. The chameleon-like properties of some of today’s universal composites enable clinicians to use a single shade of composite for diastema closure. Material advancements that allow practitioners to provide positive outcomes with direct restorative techniques in lieu of more costly indirect techniques improves accessibility and affordability of care for patients dissatisfied with their smile. In the case described, the patient and clinician designed a treatment plan that addressed the esthetic and financial concerns of the patient while also delivering sound dental care. When treatment is done in this manner, the process can truly be a win-win for all involved.