Diastema Closure

by Robert Margeas, DDS

Patient demand for esthetic dentistry with minimally in­vasive procedures has resulted in the extensive utilization of freehand bonding of composite resin to anterior teeth.1 The development of composite resins with natural fluorescence and polishability allows the clinician to mimic the natural dentition. Composite resins allow for conservative treatment and long lasting restorations. In order to achieve a natural appearing composite restoration, the clinician must have a knowledge of the properties of composites, and which materials to use in each clinical situation. There are a variety of materials to choose from including, microfills, hybrids, microhybrids, and the newer nanotechnology materials. Today’s composite resins exhibit dramatically improved physical and optical properties, rendering them the ideal materials to facilitate restorations that are indistinguishable from the natural dentition.

Dental patients are more conscious of their appearances and have raised the importance of the smile within society as a whole; this impacts full mouth restorations as well as more conservative restorative procedures that include class IV restorations, diastema closures and veneers of the teeth.2,3

Direct resin restorations require skill and commitment from the clinician. It is a learned technique. Hands on courses provide some of the best learning opportunities when trying to perfect the technique. Prior to performing a restorative procedure, the clinician must achieve a heightened sense of observation to visualize the properties (ie. opacity, form, color, characterizations, surface texture) of the natural teeth.4-7

One of the advantages of a direct resin restoration over a porcelain restoration is that the clinician is able to maintain control and customize the materials throughout the procedure. With porcelain, any modification means a return to the laboratory for correction. When choosing the proper shade of composite for a direct composite restoration, the dentist must first understand hue, chroma, and value. Hue is commonly understood as the name of the color or the basic shade. Chroma can be defined as the intensity of color or the degree of hue saturation. The most important of the color dimension is value, which distinguishes light from dark colors. The value can be defined as the brightness of color.

While excellent esthetics are possible with indirect restorations, there may be unnecessary tooth structure removed in order to achieve the desired results. This may affect the long term success of the restoration, when dealing with younger patients. When possible, augmentation versus amputation allows for a more conservative treatment option.

The diastema presents itself to the dental office on a regular basis. It may be small or large. The papilla may be long and skinny, or blunted. The size will have an effect on what material will be chosen to achieve the desired results. When dealing with a larger space closure, orthodontics may be indicated to allow for a more esthetic outcome.

When the teeth are in proper orthodontic alignment, no preparation of the tooth structure is necessary. If there is an alignment problem, minor tooth preparation will be necessary to achieve proper arch form. The following case report shows a restorative protocol when addressing the midline diastema.

A 30-year-old patient presented to the office with a small, 2mm midline diastema (Fig. 1). It was his desire to have the space closed. The pre-op retracted view revealed excellent tissue health and an ideal color (Fig. 2).

The only treatment option given to the patient was to restore the teeth with composite resin. The ideal alignment meant that no tooth structure would be removed prior to restoring the case. Although a rubber dam could be used for isolation, in this case, cotton roll isolation was used.

Depending on operator preference, either tooth could be restored first. The right central incisor was acid etched for 20 seconds, rinsed and air dried (Fig. 3). The enamel exhibited an excellent etch pattern. The adhesive was applied in a thin layer and lightly air- thinned. It is important not to allow the unfilled resin to pool around the gum tissue. If this occurs, the composite will not be able to be placed subgingivally.

A single shade of composite was chosen that will provide a chameleon effect when placed (Fig. 4). The composite is placed using a long bladed titanium instrument and sculpted beneath the free gingival margin (Fig. 5). The lingual must be contoured as well to prevent any voids or open margins. The material is usually placed in one increment and sculpted free hand to the desired shape. A brush (Fig. 6) was used to thin the material out as much as possible, trying to avoid a thick margin. It is important that you over etch the surface, because you do not know exactly where the composite will end. You blend the material until the margin disappears.

Figure 7 shows the final cured composite prior to finishing. The final material is cured for 40 seconds from all angles. A carbide bur is used to contour and finish the margins.

Finishing disks, from coarse to extra fine are used from composite to tooth. This will provide an undetectable margin. It is important to overbuild the first tooth so that when polishing is finished, it will be the proper size. The adjacent tooth can now be etched. A clear matrix strip is placed interproximally to prevent etching the adjacent tooth (Fig. 8). When using this technique, it is imperative that the first tooth be finished and polished to completion. This will not allow the composite from bonding to the first restoration. If the polish is not smooth, the second tooth will bond to the first one and the restoration will not be able to be separated.

This freehand technique will allow for a perfect contact without using wedges or matrices. Another increment of composite is added to the second tooth following etching and placement of adhesive resin (Fig. 9). This is once again sculpted on the facial and lingual using titanium instruments, and brushes; making sure it is tacked subgingivally without an overhang (Fig. 10). This is allowed to be cured against the adjacent, finished restoration. Once this is light cured it will stick to the first restoration, but not bond due to the highly polished surface. An instrument is placed between the two composites and lightly torqued to separate them (Fig. 11). A clear mylar strip is then placed between the teeth and subgingival so that the lingual wall can be formed against the cured facial wall (Fig. 12). A small piece of composite is placed on the lingual and the mylar strip is pulled toward the cured facial wall with light pressure on the lingual to fill in the lingual void (Figs. 13 & 14). The final unfinished restoration is shown in Figure 15. An instrument is placed at the cervical area and torque once again to separate the teeth. Instruct the patient that they will hear a pop. The tooth is now finished with carbide burs, disks, diamond strips, and finishing strips to allow a smooth interproximal surface. A Flexi-Buff and Enamelize insures a high gloss (Fig. 16). Figures 17 and 18 show the final restorations on the day of placement. After the patient saw the final result, the diastema between the right lateral and central was closed at another appointment.

Composite resin is an ideal material when restoring diastema closures. It is highly polishable, long lasting, and mimics natural tooth structure. It is a conservative alternative to an indirect restoration. Freehand bonding allows the dentist to be an artist and gives total control to the operator.OH

Dr Margeas is Board Certified by the American Board of Operative Dentistry and is an adjunct professor in the dept of operative dentistry at the U. of Iowa College of Dentistry. He is on numerous editorial boards and lectures and performs hands-on courses internationally. He maintains a private pra
ctice in Des Moines, Iowa.

Oral Health welcomes this original article.

1. Dietschi D. Free-hand composite resin restorations: A key to anterior esthetics. Pract Periodont Aesthet Dent 1995;7(7):15-25.

2. Fahl N Jr. Optimizing the esthetics of Class IV restorations with composite resins. J Canad Dent Assoc 1997;63(2):108-115.

3. de Araujo EM, Baratieri LN, Monteiro S, et al. Direct adhesive restoration of anterior teeth: Part 1. Fundamentals of excellence. Pract Proced Aesthet Dent 2003;15(3):233-240.

4. Winter R. Visualizing the natural dentition. J Esthet Dent 1993;5(3):102-117.

5. Terry DA, Geller W, Tric O. Anatomical form defines color: Function, form, and esthetics. Pract Proced Aesthet Dent 2002;14(1):59-67.

6. Ten Bosch JJ, Coops JC. Tooth color and reflectance as related to light scattering and enamel hardness. J Dent Res 1995;74(1):59-67.

7. Sproull RC. Color matching in dentistry. The three-dimensional nature of color. J Prosthet Dent 1973;29(4):416-424.