A Predictable Way to Close the Gap by Dr. James Peyton

Introduction
Diastema closure can be considered one of the most conservative restorative procedures we can offer our patients. Classically, little to no preparation is necessary, short of abrading and cleaning the adjacent surfaces to be restored.

The key elements to consider in this treatment option are symmetry, proportion and the balancing of the midline to the long axis of the face. The smile begins with the central incisors, and therefore it is critical to have these teeth as close to mirror images of each other as possible and in the correct proportions. In the completed restorations, any cant in the midline will result in an aesthetic failure.^1,2 A microfill or a highly sculptable supra-nano-filled composite would be ideal for this procedure.

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  Fig. 1. The preoperative smile view reveals an unattractive smile.

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  Fig. 2. The retracted 1:1 view shows the worn and discolored composite restorations between teeth #8 and #9.

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  Fig. 3. A custom shade guide was used to select the replacement.

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  Fig. 4. The old bonding was removed.

Case history
A 40-year-old patient was not happy with the bonding between her front teeth, which had worn down, chipped and become discolored (Figs. 1 and 2). She asked for it to be replaced with new material.

Treatment
The shade was selected at the beginning of the appointment with a mock-up, using the same composite anticipated in the final restoration. The selected shade was EA1 from Estelite Omega, a supra-nano-filled composite from Tokuyama Dental America. Shade selection was made easier because the shade guide was made from the composite material. Based on the trial mock-up, only one composite shade was necessary for the diastema closure (Fig. 3).³

A digital caliper was used to measure the distal-to-distal distance between teeth #8 and #9. This measurement (16.92 millimeters) was divided in half to obtain the individual width of each central incisor (8.46mm). The old, discolored bonded restorations were removed (Fig. 4) with a fluted carbide bur (ET9 from Brasseler). The teeth were cleaned off with pumice (no fluoride) and the mesial-facial of both teeth was lightly abraded with a coarse Sof-Lex XT disc (3M ESPE). This was not to reduce tooth structure, but to remove the aprismatic, outer surface layer of enamel, thus resulting in a stronger bond.⁴ Packing cord (OO, UltraPak from Ultradent) was placed on the mesial-facial of #8 and #9. Teflon tape was placed on #8 to protect it from etch and bonding agent^5,6 (Fig. 5).

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  Fig. 6. Etchant was applied to the mesial half of #9 and Teflon tape protects #8.

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  Fig. 7. Bonding agent was applied to #9.

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  Fig. 8. Composite was added to the mesial of tooth #9.

Tooth #9 was etched with 35 percent phosphoric acid (Ultra-Etch from Ultradent) and rinsed with water (Fig. 6, pg. 66). Bonding agent (Prime & Bond NT from Dentsply Caulk) was applied on the mesial contact area and halfway across the facial surface, then light-cured (Fig. 7). Shade EA1 was added to the mesial-facial (Fig. 8), built out to the anticipated width of 8.46mm and contoured on the facial with a gold Almore instrument and smoothed with a #3 artist's brush (Tokuyama Dental America) wetted with modeling resin (Bisco). The restoration was then light-cured for 20 seconds with an LED curing light (Valo from Ultradent).

Estelite Omega was then added to the lingual area of #9 and light-cured. The width of #9 was checked with the digital caliper and found to be slightly wider than the 8.46mm ideal width. The large coarse disc and finishing strips were used to obtain the ideal width (Fig. 9) and generate a high polish. The patient was moved to the upright position and the midline was evaluated to be completely straight up and down, preventing the final restorations from having a midline cant. The smooth surface and high polish on the mesial of #9 will prevent composite from #8 sticking to the restoration.7

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  Fig. 9. The future width of #8 was equal to the restored width of #9.

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  Fig. 10. Composite was added to the mesial-facial of tooth #8, just shy of the contact area.

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  Fig. 11. The incisal view shows tooth #8 and the facial embrasures.

Teflon tape was then placed on the restored tooth. Tooth #8 was acid-etched, rinsed and coated with a bonding agent, as was previously done to tooth #9. Estelite Omega was added to the mesial-facial of #8, then sculpted to match the contour of #9. A slight space was left between the teeth (space of a thin IPC) and then light-cured.

A clear Mylar/plastic strip was placed between the teeth and composite was added to the lingual of tooth #8. This composite material was then sculpted into the contact area with excess left on the lingual. The Mylar strip was then pulled through to the facial. There was a slight excess of composite on the facial, which was then contoured with a thin IPC (Cosmedent). The composite on the lingual was sculpted so that the contact area was even. The facial, lingual, incisal and gingival embrasures were contoured to have an even and symmetrical contact area. The restoration was then light-cured (Figs. 10–13, p. 68).

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  Fig. 12. The clear Mylar strip is placed between the teeth and composite material was added to the mesial-lingual of #8.

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  Fig. 13. The final buildup of composite material.

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  Fig. 14. The postoperative smile view shows nice symmetrical composite restorations.

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  Fig. 15. Postoperative retracted view.

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  Fig. 16. The postoperative portrait shows a happy patient with a beautiful new smile.

Observation of the teeth from the occlusal view was essential to evaluate facial contours and embrasures. A series of Sof-Lex discs were used to create an even and highly polished surface. Care was taken to have the proximal line angles even and well defined. The secondary anatomy was created by the development depressions on the facial surface. Drawing the proximal line angles and a line in the middle of the tooth can assist in creating these contours. With the use of a flame tip carbide or diamond, the operator can carefully create a smooth depression area between the lines on the facial.

A slight developmental depression was created on the mesial of both #8 and #9 with a flame-tip carbide (7901 from Brasseler). This depression area should be shallow and smooth. Next, blue and pink rubber cups (Cosmedent) were used to polish the restoration. A blunt composite instrument was used to slightly torque the teeth to "pop" the contact. Finishing strips and a #12 Bard-Parker were used to contour and smooth the gingival/interproximal contours. The contact area was checked with dental floss. There was a tight contact with no catches or shredding of the dental floss. FlexiBuff and Enamelize (Cosmedent) were used to give the restorations a high polish that matched the shine of the natural tooth^8,9,10 (Figs. 14–16).

Conclusion
The end result showed central incisors that were mirror images of each other and oriented in the face in a symmetrical and balanced position. A conservative and successful restoration of a midline diastema was accomplished with an excellent material by following a predictable step-by-step technique.

The goal from the beginning was to create a restoration that matched the shade of the natural tooth with a similar polish, and to have teeth that were mirror images of each other, and did not have a midline cant. This goal was achieved and the patient was very excited to have her beautiful smile restored.

References
1. Finlay Scott. Conservative esthetics using direct resin. Inside Dent. 2010 May; 6(5):96-101.
2. Crispin BJ. Contemporary esthetic dentistry: practice fundamentals. Carol Stream (IL): Quintessence Pub.; 1994:116-127.
3. Fahl N. Mastering composite artistry to create anterior masterpieces, part 1. J Cosmetic Dent. 2010 Fall; 26(3):56-68.
4. Relationship Between Enamel Etch Characteristics and Resin-enamel Bond Strength; Hobson, RS, McCabe, JF, British Dental Journal, 192, 463-468 (2002) Published online: 27 April 2002 | doi:10.1038/sj.bdj.4801401
5. Manauta J, Salat A. Layers: an atlas of composite resin stratification. Milan, Italy. Quintessence Pub.; 2012; 349-375. http://www.quintpub.com/PDFs/book_preview/B9520.pdf
6. Peyton JH, Arnold JF. Six or more direct resin veneers case for accreditation: hands-on typodont exercise. J Cosmetic Dent. 2008 Fall; 24(3):38-48.
7. Hatkar P. Preserving natural tooth structure with composite resin. J Cosmetic Dent. 2010 Fall; 26(3):26-36.
8. Fahl N. Mastering composite artistry to create anterior masterpieces, part 2. J Cosmetic Dent. 2011 Winter; 26(4):42-55.
9. Rufenacht C, Lee R. Fundamentals of esthetics. Inc. Chicago (IL): Quintessence Pub.; 1990:117-127.
10. Peyton, James. Finishing and polishing techniques: direct composite resin restorations. Pract Proced Aesthet Dent. 2004 May; 16(4):293-8.

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