Posterior Restorations in a multidisciplinary approach

The development of technology and the continuous scientific research on materials and techniques allow us today to simplify daily clinical practice, obtaining predictable and performing results. Although knowing and implementing appropriate techniques is important, the contemporary digital workflow simplifies indirect restoration procedures for the correct rehabilitation of compromised teeth. Indeed, the latest generation scanners at our disposal are highly performing, quickly obtaining satisfactory results if we use operational techniques that are revisited and adapted to digital procedures. This clinical case presents a digital workflow rehabilitation, highlighting its performances.

style italiano style italiano teeth with old amalgam restorations

Fig.1
Initial situation, the 65 y.o. patient presented old amalgam restorations (performed by myself 40 years earlier). The extensive amalgam restoration at tooth 16 was replaced with an indirect restoration in order to maintain and preserve the integrity of the tooth, while teeth 14 and 15 were later restored directly.

style italiano style italiano tooth after removal of extensive amalgam restoration

Fig.2
After rubber dam application, the old restoration was removed and sclerotic dentin was exposed.

style italiano style italiano etching the enamel before build-up

Fig.3
Once the surface was cleaned, a selective enamel etching was carried out with 37% orthophosphoric acid for 30 seconds.

style italiano style italiano flowable composite for cavity build up and deep margin elevation

Fig.4
After the application of the adhesive procedures, a flowable composite was used to seal the dentin and to elevate the deep distal margin.

style italiano style italiano built-up cavity

Fig.5
A high viscosity bulk-fill composite was used to build the tooth up.

style italiano style italiano overlay preparation ready for impression

Fig.6
After that, an overlay preparation was designed and performed to quickly and easily obtain a correct digital impression that exactly reproduced the final shape of the tooth. At this point, the digital impression could be taken.

style italiano style italiano intraoral scan of overlay preaparation

Fig.7
The final scan of the preparation taken with Helios 600 (Eighteeth, China).

style italiano style italiano lower arch scan for bite registration

Fig.8
The antagonist was also scanned for bite registration.

Video.1
This video demonstration highlights how quick and easy it is to take a digital impression with the Helios 600 intra-oral scanner.

Helios 600 Eighteeth Styleitaliano Style italiano banner intraoral scanner
Helios 600 Eighteeth Styleitaliano Style italiano banner intraoral scanner
style italiano style italiano provisional restoration

Fig.9
Once the intra-oral scan was completed, a temporary restoration was placed to cover the entire preparation, waiting to receive the overlay restoration from the lab.

style italiano style italiano digital model and wax up

Fig.10
Moving on to the laboratory, the final design of the indirect overlay was created, checking the correct contact points and the finish line of the restoration.

style italiano style italiano analogical wax up on 3d printed model

Fig.11
From digital to analogical, the wax-up of the indirect restoration was performed.

style italiano style italiano from wax up to lithium disilicate artifact

Fig.12
As for the digital workflow, also for the analogical one the contact points and the finish line were checked. After that, the lithium-disilicate restoration was fabricated from the wax-up model.

style italiano style italiano lithium disilicate overlay

Fig.13
The finished lithium-disilicate restoration is ready to be cemented.

style italiano style italiano isolated overlay preparation ready for cementation

Fig.14
After removing the temporary restoration, the surface of the preparation was sandblasted and cleaned.

style italiano style italiano etching of overlay preparation

Fig.15
Orthophosphoric acid was applied on the entire bonding surface for 30 seconds.

style italiano style italiano bonding of overlay preparation

Fig.16
Scotchbond Universal Plus was applied on the surface, rubbing and scrubbing the brush accurately. After air-blowing, the bonding agent was polymerized for 40 seconds.

style italiano style italiano excess cement removal during overlay cementation

Fig.17
A resin cement was applied on the internal surface of the indirect restoration and then the overlay was fitted with a constant pressure. A 5 second tag-curing was used to harden the excess cement in order to remove it easily with the Eccesso tool of LM Arte kit (LM Dental).

style italiano styleitaliano lm arte anterior instruments
style italiano styleitaliano lm anterior instruments
style italiano style italiano glycerine gel applied for final light curing of cemented overlay

Fig.18
Glycerine was applied to prevent oxygen inhibition of the superficial resin cement layer, and the curing was completed with another 1 minute cycle.

style italiano style italiano cemented overlay restoration after rubber dam removal

Fig.19
Final result after rubber dam removal. The two amalgam restorations will be replaced in a following session with direct composite restorations.

Conclusions

In an ever-evolving world we should really implement the tools we’re offered by contemporary technology in our everyday practice. Once protocols are adapted and set to standard, digital instruments make our work easier and more predictable.

Bibliography

Coachman C, Sesma N, Blatz MB, The complete digital workflow in interdisciplinary dentistry Int J Esth Dent. 2021;16:1.
Tsirogiannis P, Reissmann DR, Heydecke G. Evaluation of the marginal fit of single-unit, complete-coverage ceramic restorations fabricated after digital and conventional impressions: A systematic review and meta-analysis. J Prosthet Dent 2016 Sep;116(3):328-335.e2.
Hasanzade M, Aminikhah M, Afrashtehfar KI, Alikhasi M. Marginal and internal adaptation of single crowns and fixed dental prostheses by using digital and conventional workflows: A systematic review and meta-analysis, J Prosthet Dent. 2021 Sep;126(3):360-368. Epub 2020 Sep 12.

style italiano styleitaliano Essential Dentistry kit online on demand course
style italiano styleitaliano Essential Dentistry kit online on demand course

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