wax overlay on model

Overlay goes digital

Endodontically treated teeth need cusp protection, most of the times, be it with partial or complete restorations.
In this case, the tooth was reconstructed using a fiber post, but luckily quality and quantity of residual enamel allowed us to restore this tooth with a lithium disilicate overlay to protect it towards masticatory loads. This case was performed using a digital workflow.

tooth after endodontic treatment

Fig.1

After the RCT a fiber post was cemented and a composite build up was done to seal the tooth. Residual enamel was thick and good, so we decided to only proceed to cusp coverage by fabricating an overlay.

color check for overlay fabrication

Fig.2

The shade for the indirect restoration was taken before preparing the cavity.

overlay cavity design on molar

Fig.3

The tooth was prepared to achieve complete cusp coverage as it wasn’t vital, and neighboring teeth were polished.

digital scan of overlay preparation

Fig.4

A digital scan was taken, here you can see a screenshot from the .stl file and details of the preparation without the high definition

stl impression file for overlay

Fig.5

CAD file before the project showing contact points

overlay on digital model

Fig.6

CAD design showing unchanged occlusion on the neighboring teeth, and the onlay project.

waxed overlay design

Fig.7

After CAM processing, check of the physical wax project.

lithium disilicate overlay on printed model

Fig.8

A pressed lithium disilicate overlay was fabricated and then colored and polished.

overlay preparation

Fig.9

Isolation with rubber dam before adhesive cementation.

try in of lithium disilicate overlay

Fig.10

Try in was carried out under rubber dam isolation to check proximal and marginal fit.

detail of marginal overlay adaptation

Fig.11

Marginal adaptation was checked on all sides.

etching of preparation

Fig.12

Enamel and composite build-up were etched using 37% orthophosphoric acid.

adhesive application with microbrush

Fig.13

A universal adhesive system (Scotchbond Universal, 3M) was used for bonding.

processing of overlay surface

Fig.14

The surface of the overlay was treated using hydrofluoric acid, polish and adhesive.

luting of overlay with composite excess

Fig.15

Heated composite (A3 Filtek Bulk One, 3M) was used for cementation.

overlay after cementation with excess

Fig.16

After light curing and excess removal, before finishing.

comparison of occlusion between digital project and reality

Fig.17

Here you can see how similar the final outcome is in reality compared to the digital project.

cemented lithium disilicate overlay

Fig.18

At check-up, 10 days later. Integration is satisfactory.

lithium disilicate overlay on molar

Fig.19

At check-up, 10 days later.

Conclusions

Adhesive indirect restorations are an excellent solution to give stability and resistance to endodontically treated teeth while saving sound tissue.
Using the correct build-up technique it is possible to preserve healthy enamel. New technologies and materials allow dentists to work in an aesthetic and accurate way.

 

Credits
Thanks to DT Alessandro Arnone for the fundamental contribution.

Bibliography

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