Colorimetry, minimal orthodontics and direct composite protocol to treat a diastema
A clinical cases by our Community member Dr Pantelis Kouros.
A young female (20 y.o) with a hypertrophic lingual frenum that was almost separating the upper alveolar process at half, and was causing a large median diastema. The main complaint was about the aesthetic rehabilitation of the diastema. The position of the central incisors indicated that reproducing golden proportions would be unachievable without minimal movement of teeth. The case was treated with minimal teeth movement and direct composites. The shade selection was done with a digital comparison of an image file to the tissues.
Initial situation. The width of the diastema was such that any kind of solely additive treatment would lead to oversized and unaesthetic central incisors. This was explained to the patient with the use of a direct composite mock-up, and she decided to proceed with the optimum treatment scenario, without sacrificing any sound tooth structure.
Palatal view where attachment of a thick binding tissue bundle to the palate is distinguishable.
Initially, a simple surgical frenectomy utilizing a traditional approach with scalpel was performed.
One week after the surgery and already a slight tilting towards mesial line of the incisors is already visible. This tilting occurred passively, without any forces applied on the teeth.
Clear aligners were manufactured to assist moving of upper incisors to the planned position. That way, rehabilitation of the occurred diastemata could be treated in a completely prep-less approach.
One month and two sets of aligners later, teeth are in an optimal position according to the plan.
For shade selection, at that time, a colorimetric approach with button-tries was used. Today, all data regarding composite shade is stored in the Dental Shade Navigator application, which ideally cooperates with a mobile phone picture acquired with MDP from Smile Line.
Composite L, A and B values were calculated in comparison with teeth to assist shade selection, which was made using those colorimetric parameters. The software used for this stage was Lightroom. The very early description of such procedure was introduced by Ed MacLaren who utilized Photoshop in a similar way.
For isolation, a black rubber dam (Nic Tone) was chosen based on prioritization of lightness (L) over blue-yellow (B axis) for this case. When yellowness is of priority for a given case, blue rubber would be helpful because blue allows better separation on viewing yellow shade as it is the opposing color on the spectrum.
Surfaces to be bonded were sandblasted with 29 micron (Aquacare) particles, and etched with orthophosphoric acid 37% for 60 seconds.
A universal bonding agent (pH=2.3) was used for this case.
After building up the first mesial proximal area, a pre-curved metal matrix (Tor-VM) was used to form a proper interdental space. Contact point positioned 5 mm above the crestal bone as defined during surgery. This was to ensure that soft tissue fill the interdental space and no black triangle be visible after healing.
Dentin shade (MD, Essentia) layered up to contact point and gradually transitioned to enamel (DE Essentia). This would reproduce the intensive opalescent areas that were present in those young teeth.
A meticulous finishing with rubber cones and paste-polishing procedure is always necessary.
While polarized images are valuable for shade matching, a reflective observation under different angles is necessary to estimate polishing and reflective surfaces created. This is a 12 o’clock view with the light positioned directly against incisal edges.
An oxygen blocker and completion of polymerization always is a must. To me, the most beneficial stage to do so, is directly prior to rubber dam removal.
Post-op. A black triangle is present below the contact point.
Recall after one week. Soft tissue has covered the gap according to Tarnow’s principles. Shade is satisfactory, proportions as well.
The opalescent effect that perfectly blends in with the natural tissues is more visible from this left-sided view.
The ultimate shade test are polarized images. A close observation can reveal the different layers of composite and the way they were placed. Dentin, which is more chromatic and more translucent compared to natural dentin is layered at cervical area, while enamel, responsible for the opalescent effect resembles natural enamel and is placed in a thicker layer for the left incisor.
Side view of the final result.
The minimally interventionist aesthetic approach when teeth are not in an ideal position may involve minimal repositioning with the aid of clear aligner appliances. The procedure can be fast, predictable and provide the potential to preserve sound tissues which would be sacrificed with a more aggressive approach. Alternatively, additive treatment, without further interventions, could result too far from ideal from an aesthetic standpoint. Knowledge of principles of biology regarding teeth movement and soft tissue management are considered to be necessary.
For shade selection, the digital approach is more reliable than visual estimation. Color is a measurable value and the digital tools available can be of invaluable help. Several methods have been suggested so far to process an image file for colorimetry purposes. The case presented is based to the most early color estimation protocols without image calibration, yet with comparable measurements of simultaneously depicted elements. Today don’t need to constructing buttons in each patient’s mouth anymore, since we have a colorimetric database that cooperates with a downloadable application (Dental Shade Navigator).
The use of a mobile device along with a Mobile Dental Photography equipment (MDP, Smile Line) beneficial since is providing the potentiality of a live shade selection. Furthermore, utilizing the live view mode of the mobile camera, a direct estimation of the surface gloss, quality and reflective surfaces, which is helping achieving high end aesthetics for our direct restorations.
1. Tarnow DP, Magner AW, Fletcher P. The effect of the distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla. J Periodontol. 1992;63(12):995-996. doi:10.1902/jop. 19126.96.36.1995
2. McLaren EA, Figueira J, Goldstein RE. A Technique Using Calibrated Photography and Photoshop for Accurate Shade Analysis and Communication. Compend Contin Educ Dent. 2017;38(2):106-113.
3. Manauta J, Salat A, Putignano A, Devoto W, Villares CF, Hardan LS. Natural, polarized light and the choice of composite: a key to success in shade matching of direct anterior restorations- Part I. Odontostomatol Trop. 2016;39(155):11-19.