The success of any restoration involving the proximal area, such as direct veneers, strictly depends on proper matrix selection. The aim of any matrix is to produce a cleanable, anatomical restoration with a smooth convex surface, continuous with the remaining tooth structure, with the contact area at the maximum convexity of the intact adjacent tooth. Although many matrix types for direct restoration are available, we can either use a metallic sectional matrix to build the proximal walls one at a time, to frame the veneering area, or we can use the Unica anterior matrix (Polydentia). Unica anterior is the ideal matrix to perform direct class III, IV, and V cavity restorations, and aesthetic restorations, such as direct stratification of composite veneers, and shape modifications of maxillary incisors. Thanks to its contoured shape, Unica anterior facilitates the restoration of proximal and cervical margins simultaneously, even in the presence of a rubber dam or gingival retraction cords, thus reducing the time needed for the procedure. In this article, we will show how we can use Unica to frame the tooth to facilitate and enhance direct veneering in a feasible way.
Fig.1
Initial photo of a young lady’s smile complaining of brown and yellow discolorations, wanting to smile confidently.
Fig.2
There was mild to moderate fluorosis on her teeth characterized by yellowish brown discoloration. The treatment of fluorosis depends on the severity of the affected enamel. A retracted view showed that the yellowish-brown discoloration was mainly related to the upper teeth. The appearance of teeth affected by moderate-to-severe fluorosis can be significantly improved by various techniques, ranging from bleaching, resin infiltrations, microabrasion, direct veneering, or indirect restorations. As the patient had limited time and budget, direct veneering suited the patient’s needs.
Fig.3
In the treatment plan goal is to mask the discolorations and do shape correction, especially incisal embrasures, to follow the curve of the smile and give the illusion of a natural-looking smile.
Fig.4
Shade was selected using custom shades fabricated from the White Dental Beauty CompoSIte System. Five dentine shades, and only one enamel shade. We selected a suitable shade according to the patient’s desire, and to be harmonious with her lower teeth.
Fig.5
A little preparation here was mandatory to remove the affected enamel, and to ensure the application of universal adhesive on sound enamel as preparation of enamel improves the resin-enamel bond strength on teeth affected by fluorosis, which effectiveness is lower on unprepared teeth.
Fig.6
Rubber dam isolation is required to have a clean environment, free from contaminants and with a clear vision. A split dam was used to facilitate the positioning of the Unica matrix to retract and seal the cervical part.
Fig.7
Acid etching was done for 30 seconds (3M ESPE) and then washed for 60 seconds to ensure complete removal of the etching gel.
Fig.8
The frosty white appearance is a good indicator of enough etching.
Fig.9
A universal adhesive (3M ESPE) was applied and actively rubbed against the surface to ensure complete wetting of the etched enamel.
Fig.10
The adhesive layer was light-cured for 20 seconds using the Curing Pen (Eighteeth).
Fig.11
Restoring using the Professional CompoSite System
One dentin shade was used to restore the entire labial surface, and one enamel shade was placed at the incisal third only. Simple, fast, and natural. In instances where a younger patient requires a little more brightness, the Si E shade (Enamel) is the perfect option, as it takes up the color of the body material for a natural appearance.
Also, when we do this, we overcome the issues related to excessive enamel thickness such as the glass effect.
Fig.12
The palatal shells were built freehand using the Enamel shade (White Dental Beauty) supporting a mylar strip with a firmly positioned finger.
Fig.13
There are two types of Unica matrix, Regular and Mini deep.
Regular unica is a hard-stainless steel alloy with 30 microns designed for all anterior restorations and fits the central incisors, canines, and large teeth.
Unica mini deep is soft stainless-steel 30 microns with a malleable alloy that can easily be placed and shaped to fit small teeth like lateral incisors, lower anterior, and teeth with narrow cervical diameter.
Fig.14
A good matrix system is key to success in direct anterior restorations, to help recreate the natural shape of the tooth with aesthetic results. If we achieve a perfect outline of the two centrals, it will be easy to copy the outlines and contour pattern to the laterals and canines. This is very important as the eye always focuses on the midline, i.e. the two centrals. For multiple anterior restorations, multiple Unica matrices can be placed simultaneously, with regular unica for centrals and mini deep for laterals. One of the advantages of using Unica is the outer shape can be easily predicted, symmetry quickly obtained, and the midline can easily be located.
Fig.15
What do we mean when talking about the Unica frame? A frame is produced when building the proximal walls and cervical with the Unica matrix, which helps predict the restorations’ final shape, control the amount of composite material during layering, and subsequently decrease the time for finishing and polishing. Once the frame is outlined, the teeth are ready to receive the veneering material which can be easily layered and smoothened, while keeping good control over the amount of material. The final shape is thus easily obtained thanks to the previsualization offered by the Unica matrix.
Fig.16
TIP: sometimes, at this stage, we can remove the cervical overhang (red), if present. Moreover, if restorations are over-contoured, the proximal walls should be decreased to be at the same level labially. Over-contoured (yellow) walls mean layering much more composite material than needed, which might lead to overcontoured, bulky restorations, and increase the time of finishing and polishing.
Fig.17
After layering the veneering material (SI2 dentin, White Dental Beauty) on all teeth, an incisal spacing is left for the final characterized enamel layer.
Fig.18
Layering the final enamel layer (E shade, Whie Dental Beauty) requires thorough smoothening to facilitate finishing and polishing procedures.
Fig.19
Shaping the three facial planes using a coarse disc.
Fig.20
Shaping the transitional lines and the curvature of the mesio-distal halves using a coarse disc at low speed.
Fig.21
We use the diamond perio bur at low speed to create the secondary anatomy. We use the body of the bur incisally, and the thinner tip towards the cervical to make the narrow part.
Fig.22
A twist rubber wheel can be used to easily pre-polish all surface details, labial and proximal, at a 45 degree inclination from cervical to incisal with intermittent touches to remove all surface irregularities and sharp areas, while keeping the surface texture. The active end of the rubber is the edge, not the flat surface as compared to the disc.
Fig.23
The Lucida™ Star and The DiaShine Lucida™ Paste allow for a single-step high-gloss polishing of composite restorations.
Fig.24
Immediately after finishing and polishing.
Fig.25
Two-week follow-up.
Fig.26
Two-week follow-up.
Fig.27
Side view.
Fig.28
Side view.
Fig.29
Final smile.
Conclusions
Building the outer frame is key to success in direct veneering. The Unica matrix facilitates the entire procedure and allows practitioners to overcome the challenges they face while working on multiple teeth. Its special shape helps predict and visualize the final shape, midline, and symmetry of the composite veneers, while controlling the amount of composite used, thus decreasing the time spent finishing and polishing, and that of the entire session.
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