Fully digital post, core and crown replacement

Cosmetic Dentistry

Simon Chard

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Simon Chard showcases how technological advancements in intraoral scanners helped restore four failing anterior teeth.

With the advent of significant technological advancements in intraoral scanners, we can scan deeper than ever before with a high degree of accuracy.

These capabilities offer new restorative methods for traditional prosthodontic work. For example, we can now scan the full internal fixture head of an implant. This has many exciting possibilities moving forward.

The patient presented with failing crowns on all upper incisors (Figures 1 and 2). UL1, UR1 and UR2 all had existing metal post and cores.

The treatment plan was to remove all crowns, remove caries, re-root canal treatment (re-RCT) UR1, UL1 and UL2 (to be completed by Dr Noman Athwal), change posts where necessary (UL1 and UR1) and improve marginal position and aesthetics of all crowns.

All definitive restorative work would be manufactured chairside by myself using the Cerec Primescan and MCXL (Dentsply Sirona).

Following dismantling and caries removal, the teeth were provisionalised with Luxatemp (DMG) crowns to facilitate endodontic retreatment.

Following removal of the crowns, it was clear there was minimal ferrule on the centrals. This was evident especially on the UR1 (Figure 3).

The options were discussed with the patient for crown lengthening surgery or XLA and implant. However, the patient elected to retain without surgery.

Following endodontic retreatment of UR1, UL1 and UL2, the patient returned for the final restorations.

These would be delivered in a single visit with Cerec same-day technology.

We elected to retain the RCT and post on UR2 given that they were in good condition with no leakage.

A split dam was placed, the temporary posts on the central incisors were both removed and the pulp spaces carefully refined and cleaned using ultrasonic restorative instruments (Figure 5).

The full depth of the pulp space was then scanned in with the rubber dam still in place (Figure 6).

The outline of the core was marginated and post and cores designed on the Cerec 5.1 software (Figure 7).

These post/cores were then milled out of a high translucency Enamic hybrid composite/ceramic block (Vita) using the MCXL chairside mill in around six minutes per post (Figure 8).

This material was chosen biomimetically. The aim was to replicate the optical and physical characteristics (such as modulus of elasticity) of the dentine it is replacing.

Following trying the posts in, the fit surface of the posts was treated with 9% hydrofluoric (HF) acid for one minute and then silanated for a further minute so as to improve bond strength.

The posts were then bonded to the dentine intraorally using etch, Adhese Universal and Variolink Esthetic DC resin cement.

The metal post on UR2 was retained and masked to prevent any grey shine through from beneath the ceramic.

The technique used for this was the ‘ASC’ technique – air abrasion, silanation and composite (in this case, pink flowable composite opaquer [Cosmedent]).

The preparations were then refined with a combination of red band diamond burs and Komet ultrasonic instruments (Figure 9).

These preparations were then scanned again using the Primescan (Dentsply Sirona) (Figure 10) and four E.max monolithic crowns designed (Figure 11).

These crowns were then milled using the MCXL and hand finished using a straight handpiece with the CAD chairside ceramic finishing kit (Meisinger) (Figure 12).

They were tried in pre-glaze and occlusion and contacts checked. A polychromatic appearance was achieved utilising the 3D stain and glaze technique with IPS E.max Crystall glaze (Ivoclar Vivadent) and then furnaced for 28 minutes.

Following furnacing (Figure 13), the restorations were tried in with Variolink Esthetic Warm try-in paste to gain aesthetic consent from the patient.

Following consent, the restorations were cleaned, etched with 9% hydrofluoric acid for one minute and then silanated for a further minute.

Next, the restorations were bonded to the teeth with Variolink Esthetic dual cure resin cement. The excess removed following light-curing (Figures 14, 15 and 16).

This case demonstrates how dental professionals can use the latest digital technology and materials to create bespoke and biomimetic prosthodontic work. Using this, you can give your patient’s natural teeth the optimal chance of long-term success.

This article first appeared in Clinical Dentistry magazine. You can sign up to the magazine here.

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