Customized transparent matrix – Layering with injection molding

Tips and tricks - Community - Direct anteriors
20 Dec 2016
Fig. 1

Fig. 1 – Initial situation, frontal view. Having a space between teeth especially in an unilateral zone creates an unpleasant and unaesthetic appearance. In this case the diastema between canine and lateral was chosen to be closed. In order to have equal laterals I decided to build only the canine.

Fig. 2

Fig. 2 – Lateral view.

Fig. 3

Fig. 3 – Isolation field. We try to have a good isolation and a perfect inversion of the rubber dam. Identification of possible biofilm with disclosing solution. Removal of it and enamel air abrasion.

Fig. 4

Fig.4 – A section from a transparent contoured matrix for premolar (TOR VM) was cut with scissor.

Fig. 5

Fig. 5 – The adaptation of the matrix as cervical as possible. The inverted rubber dam tightens and holds it fixed to the tooth. The matrix is fixed in such a way to leave space for a later enamel layer and its edges are holden with tiny amount of flow making sure to stick them in a zone outside the restoration zone. We utilize the narrowness of premolar matrices in cervical part of the tooth and convex contour to get a proper emergency profile.

Fig. 6

Fig. 6 – Occlusial view of the matrix adaptation

Fig. 7

Fig. 7 – Etch and rinse of the working surface. We use a thin needle and apply it carefully not to remove the matrix. The adjacent tooth is protected with teflon. After drying we bond carefully the tooth with a minibrush and air blow. I prefer to polymerize the bond before adding composite for 60 seconds. We bond again and add a drop of high viscosity and good physical properties flow and over them inject heated composite pushing it gently in cervical region without disturbing the matrix. In this case an A3.5 body was used. We polymerize them all together in an extended time.

Fig. 8

Fig. 8 – The view after polymerization and matrix removal.

Fig. 9

Fig. 9 – Occlusal view.

Fig. 10

Fig. 10 – Now we take a bigger transparent matrix, the one for molar and cut it again.

Fig. 11

Fig. 11 – The new matrix was fixed again in place and a strong teeth separation was assured with the aid of a wedge to create a tight contact. The extremities of the matrix were stuck with flow so that the matrix touches the adjacent tooth. In this way we are ready for a second injection molding. In center, in contact with the tooth we cover with some body A3. In proximal part a heated Neutral Enamel NE was injected which covers the A 3.5 body in a progressive way from cervical to incisal basing on composite manufacturers layering guide and tooth natural anatomy. Before it, bonding and a tiny amount of flow was applied so that the composite fills every space. All was polymerized together and final polymerization was performed under glycerin.

Fig. 12

Fig. 12 – The sketched picture showing the layers.

Fig. 13

Fig. 13 – Postoperative appearance after removal of the rubber dam.

Fig. 14

Fig. 14 – Final restoration after finishing and polishing. The transparent matrices assures us a smooth surface and we do not even have to use any strip to finish it proximally.

Fig. 15

Fig. 15 – Occlusal view of the restoration.

Fig. 16

Fig. 16 – X ray check shows no cervical overhangs.

Fig. 17

Fig.17 – The restoration after 5 days. We note a good papilla response.

Fig. 18

Fig. 18 – Before and after lateral view.

Fig. 19

Fig 19 – Before and after frontal view. Note the visual difference before and after closing the space even though the teeth are not symmetric.

 

Conclusions

Even though there are a lot of matrix systems and maybe better ones, we can adjust from a normal cheap one and achieve the desired results.
Especially in an aesthetic zone it is important that the restorations should be layered to appear more natural.
A multi-injection molding technique could be utilized to layer the composite.
I want to thank dr. Indrit Dibra for consulting.

Bibliography

Brenna F. Restorative Dentistry
Takahashi N. Estelite Asteria Clinical Guide
Clark DJ. Treating the “Black Triangle” with Direct Composite – a Microscopic Perspective.
Devoto W, Saracinelli M, Manauta J.Composite in everyday practice: how to choose the right material and simplify application techniques in the anterior teeth.Eur J Esthet Dent. 2010 Spring;5(1):102-24.

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