Oral Health Group

Diastema Closure: The Direct Resin Technique

Patient demand for aesthetic 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,8 which distinguishes light from dark colors. The value can be defined as the brightness of color.

While excellent aesthetics are possible with indirect restorations, there may be unnecessary tooth structure removed in order to achieve the desired results. This may effect 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 aesthetic 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 21year-old patient presented to the office with a small, 2mm midline diastema. (Fig. 1) It was her 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 left central incisor was acid etched for 20 seconds with Ultra-Etch (Ultradent) (Fig. 3), rinsed and air dried. The enamel exhibited an excellent etch pattern. No dentin was exposed; therefore only Dentin/ Enamel resin (D/E resin, Bisco) was used. The D/E resin was applied in a thin layer, (Fig. 4) and lightly air- thinned. It is important not to allow the unfilled resin to pool around the gum tissue. If this occurs, the microfill will not be able to be placed subgingivally.

The restorative material used is Renamel Microfill composite (Cosmedent). The microfill is opacious enough that a hybrid material does not need to be used as a lingual backing. Another benefit of using a microfill is its polishability. It can mimic the surface texture of a natural tooth and the finish can remain polished over long periods of time. A single shade of microfill was chosen that will provide a chameleon effect when placed. Renamel B-1 microfill (Fig. 5) is placed using a long bladed titanium instrument and sculpted beneath the free gingival margin. 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 number 3 Cosmedent 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 microfill 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. An ET 9 bur (Brasseler) is used to contour and finish the margins (Fig. 8). Finishing disks, from coarse to extra fine are used from composite to tooth. This will provide an undetectable margin. Final polishing can be achieved by using a Flexi-Buff (Cosmedent) and Enamelize polishing paste (Cosmedent) (Fig. 9).

It is important to overbuild the first tooth so that when polishing is finished, it will be the proper size. An excellent tool to measure the diameter of the tooth is a Dentagauge (Erskine Dental) (Fig. 10). The caliper is made with long points to engage the embrasure area. This will allow an accurate measurement. The gauge is then placed on the adjacent tooth to make sure the teeth will be mirror images of each other (Fig. 11).

The adjacent tooth can now be etched. A clear matrix strip is placed interproximally to prevent etching the adjacent tooth (Fig. 12). When using this technique, it is imperative that the first tooth be finished and polished to completion. This will not allow the microfill 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. A single increment of microfill is added to the second tooth following etching and placement of the D/E resin (Fig.13). This is once again sculpted on the facial and lingual using titanium instruments, and brushes; making sure it is tacked subgingivally without an overhang. This is allowed to be cured against the adjacent, finished restoration. The final unfinished restoration is shown in Figure 14. An instrument is placed at the cervical area and twisted (Fig. 15) .Instruct the patient that they will hear a pop. This will allow separation of the teeth. 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. Figures 16 & 17 show the final restorations on the day of placement.


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.

Dr. Mar
geas currently serves as Adjunct Professor in the Department of Operative Dentistry, University of Iowa. He is an instructor at the Center for Esthetic Excellence, Chicago, IL. Dr. Margeas is board certified by the American Board of Operative Dentistry and is a Fellow of the Academy of General Dentistry. He is also a contributing consultant to Oral Health. Dr. Margeas maintains a private practice in Des Moines, Iowa.

Oral Health welcomes this original article.


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