The re-making of posterior restorations: the CAD/CAM solution

Digital - Indirect posteriors
7 Mar 2017

CAD/CAM indirect posterior reconstructions have been widely used in the last two decades with interesting outcomes; in fact, over 90% success rates have been reported both in longitudinal studies or in systematic reviews.

These type of reconstruction could be used in patients that have limited time to spend at the dental office, needing several wide posterior restorations in contiguous teeth.

Fig. 1

Img. 1 – The chief complaint of the patient was “I am not able to efficiently chew and the food gets caught in between the teeth” and “My time is very limited…” We set up two 4 hours appointments to restore, with the first one, initially the lower jaw and one week later the upper arch.

Fig. 2

Img. 2 – We remove the old restorations and all the carious tissue, then we make a immediate dentin sealing using Optibond FL – Kerr…

Fig. 3

Img. 3 – …and we seal and build-up the rest of the cavity with a flowable resin (Tetric Evo Flow – Ivoclar Vivadent). Once the rubber dam is removed, we control the light bleeding in the interpoximal areas using an hemostatic solution (Astringdent – 3M). Then the impression powder is sprayed over the prepared teeth (Cerec – Blue Cam), the impression is taken, the two inlays are designed and milled using a reinforced composite resin (Lava LT 3M).

Fig. 4

Img. 4 – We try-in the inlays, then we customize, characterize and polish the onlays. We check at this stage the marginal fit and the inter-proximal contact points, but not the occlusal contacts yet.

Fig. 5

Img. 5 – View of the 3 inlays and onlays during the CAD CAM design process.

Fig. 6

Img. 6 – The same 3 inlays-onlays, after the characterization and the final polishing, ready to be luted adhesively.

Fig. 7

Img. 7 – Clinical steps of the adhesive luting procedure: field insulation, three step adhesive application (Optibond Fl . Kerr), luting with Tetric Evo Flow- Ivoclar Vivadent.

Fig. 8

Img. 8 – Clinical check after one week, when the patient comes back to start working with the upper jaw. Please note that the restorations of the lower right jaw have not been anatomically enhanced and not characterized with stains. The restorations of the lower left jaw have, instead, been anatomically enhanced and characterized using some stains.

Fig. 9

Img. 9 – Digital impression of the intermaxillary relationship using the Blue Cam and the powder. The use of the Optragate – Ivoclar Vivadent makes this step quicker for both the patient and the operator, with or without the powder.

Fig. 10

Img. 10 – Removal of the old restorations, disinfection, etching and total etching, three step adhesive ( Optibond Fl – Kerr ), protection of the dentin and immediate dentin sealing with a flowing resin (Tetric Evo Flow – Ivoclar Vivadent).

Fig. 11

Img. 11 – Timing of the digital impression with the rubber dam still on.

Fig. 12

Img. 12 – A close-up of the Lava Ultimate Blocks immediately after the milling process.

Fig. 13

Img. 13 – Further deepening of the occlusal anatomy, characterization and polishing of the inlays-onlays after the milling fase. The final lustre is obtained using cerium oxide lab polishing paste and dry natural hair brushes.

Fig. 14

Img. 14 – Light cured stains applied in the sulci using the fine tip of an endodontic instrument.

Fig. 15

Img. 15 – Finished restorations ready to be cemented: while the operator is insulating the field, the nurse is sandblasting the inlays and applying the adhesive.

Fig. 16

Img. 16 – Steps of adhesive cementation and check one week after the cementation.

Fig. 17

Img. 17 – Before and after: full posterior rehab in two weeks time and two clinical sessions.

Fig. 18

Img. 18 – A close up of the Lava Inlays e Onlays obtainable with the CAD-CAM techniques.

 

Conclusions

Considering the encouraging outcomes of posterior indirect restorations made by CAD/CAM chairside devices, the use of such a procedure should offer, both to patients and to clinicians, a very interesting alternative to traditional analogical solutions.

Bibliography

Pol CW, Kalk W. A systematic review of ceramic inlays in posterior teeth: an update. The International journal of prosthodontics 2011;24(6):566-575.
Opdam NJ, van de Sande FH, Bronkhorst E, Cenci MS, Bottenberg P, Pallesen U, et al. Longevity of posterior composite restorations: a systematic review and meta-analysis. Journal of dental research 2014;93(10):943-949.
Dietschi D, Spreafico R. Evidence-based concepts and procedures for bonded inlays and onlays. Part I. Historical perspectives and clinical rationale for a biosubstitutive approach. The international journal of esthetic dentistry 2015;10(2):210-227.
Otto T, Mormann WH. Clinical performance of chairside CAD/CAM feldspathic ceramic posterior shoulder crowns and endocrowns up to 12 years. International journal of computerized dentistry 2015;18(2):147-161.
Laegreid T, Gjerdet NR, Johansson A, Johansson AK. Clinical decision making on extensive molar restorations. Operative dentistry 2014;39(6):E231-240.
Wagner J, Hiller KA, Schmalz G. Long-term clinical performance and longevity of gold alloy vs ceramic partial crowns. Clinical oral investigations 2003;7(2):80-85.
Federlin M, Hiller KA, Schmalz G. Effect of selective enamel etching on clinical performance of CAD/CAM partial ceramic crowns luted with a self-adhesive resin cement. Clinical oral investigations 2014;18(8):1975-1984.
Belli R, Petschelt A, Hofner B, Hajto J, Scherrer SS, Lohbauer U. Fracture Rates and Lifetime Estimations of CAD/CAM All-ceramic Restorations. Journal of dental research 2015.