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The improvement of adhesive materials and techniques in the last decades has blurred the border between conservative and prosthetic dentistry so that composite and ceramic restorations play a key role in modern dentistry.

The adhesive approach grants various advantages including maximum preservation of the remaining tooth structure, optimal sealing, esthetics and function. 

A lot of restorative options are available for the posterior region. Direct composite restorations are the first choice for small and medium cavities, but may also represent a valid option when partial or full cuspal coverage is required. It is, however, very difficult to manage the modeling of occlusal and proximal anatomy in extensive restorations, as well as to achieve proper polymerization of the composite materials. For these reasons, indirect adhesive restoration is recommended in medium to large cavities where one or more cusps are missing.

Another one of the main issues related to the restorative treatment in the posterior area is the management of subgingival margins. Cavities of large dimensions frequently extend beyond the cemento enamel junction with margins located into the gingival sulcus; when these conditions hinder the proper isolation with a rubber dam or cause the violation of the biologic width, a surgical approach may be required non order to proceed.

Case Report

A 38-years old male patient came to our office for the treatment of various primary and secondary decays. The tooth 3.6 present an extensive cavity with pulp involvement and subgingival margins (fig.1 and 2).

Fig 1
Fig 1: Pre operative condition
Fig 2
Fig 2: Pre operative Rx

During the first appointment, an adhesive composite pre-endodontic restoration and an endodontic treatment were performed on 3.6 using rotary instruments and warm guttapercha (fig.3, 4,5).

Fig 3
Fig 3: Appearance of the pulp chamber after the phases of shaping and cleaning
Fig 4
Fig 4: Cone fit intra oral rx
Fig 5
Fig 5: obturation of the root canal system

In the second session, the previous pre-endodontic restoration was removed with burs and a surgical crown lengthening was performed in order to reestablish the correct relationship between the cervical margin of the cavity on 3.6 and the supracrestal attachment. Once the flap had been elevated, ostectomy and osteoplasty were performed using dedicated burs and sonic inserts. Vertical mattress sutures were placed to secure the flaps at bone level (fig. 6) and then the rubber dam was immediately placed providing a proper isolation of the quadrant. Under the rubber dam, the cavity of 3.6 was refined and a post space was drilled in the distal canals using dedicated burs (fig.7).

Fig 6
Fig 6: Surgical exposition of the distal margin of 3.6
Fig 7
Fig 7: immediate post surgical rubber dam isolation and post space preparation.

The M.i.M technique (Magne 2021) was used to relocate the distal margin to facilitate the following impression and bonding procedures (fig 8).

Two fiber posts were luted at full depth using a self-adhesive resin cement, then a 3-step bonding system was applied and a build-up restoration was performed with A2 shaded composite using an oblique layering technique. The tooth 3.6 was hence prepared for an indirect full coverage indirect restoration and two class 2 cavities were opened on 3.7 (occluso mesial) and 3.5 (occluso distal) (fig. 9).

Fig 8
Fig 8: Insertion of a sectional matrix between tooth and circumferential matrix for deep margin elevation.
Fig 9
Fig 9: Overlay preparation of 3.6 and cavities of 3.7 and 3.5 after removal of previous restorations and cleansing.

The teeth 3.5 and 3.7 were restored directly with composite using a circumferential anatomic matrix system and a bulk and body technique (fig. 10, 11, 12).

An intra oral scan was carried out before removing the rubber dam and closing the session (fig.13).

Fig 10
Fig 10: Matrix placed on 3.7
Fig 11
Fig 11: Matrix placed on 3.5
Fig 12
Fig 12: 3.7 and 3.5 direct composite restorations completed.
Fig 13
Fig 13: Intra oral scan before removing rubber dam.

During the third appointment, sutures were removed and a lithium disilicate overlay (fig. 14) was tried in.

Fig 14
Fig 14: Lithium Disilicate Overlay

The quadrant was isolated with rubber dam and the restoration seating was checked again (fig. 15-16). The cavity on 3.6 was then sandblasted with AlO2 (fig. 17) and a three-step adhesive system was applied onto the preparation (fig. 18-19-20)

Fig 15
Fig 15: Try in
Fig 16
Fig 16: Seating accuracy check
Fig 17
Fig 17: 50 micron AlO2 sandblasting of 3.6 cavity.
Fig 18
Fig 18: Etching with ortophosphoric acid 37%
Fig 19
Fig 19: Bonding application
Fig 20
Fig 20: Cavity appearance after bonding polymerization

The intaglio surface of the lithium dislocate overlay was etched with 5% hydrofluoric acid for 20s (fig. 21). After rinsing, the ceramic restoration was treated with 37% ortophosphoric acid for 30 sec and then cleaned in ultrasonic bath for 4 min before silanization (fig. 22).

Fig 21
Fig 21: 5% hydrofluoric acid etching for 20s of the intaglio surface
Fig 22
Fig 22: Silane application
Fig 23
Fig 23: Cement application

A high filled flowable composite was used for bonding procedures: the cement was placed onto the intaglio surface (fig. 23), the restoration was seated onto the preparation (fig. 24) and kept in position while the excesses were removed and polymerized for 60 s for each side (occlusal, buccal and lingual). Block out with glicerine was applied and polymerization was performed for another 30 sec before finishing and polishing step (fig. 25).

Fig 24
Fig 24: Luting procedures
Fig 25
Fig 25: Finishing and polishing of the margins
.

The rubber dam was removed and occlusal contacts was checked with an articulation paper (fig. 26).

Fig 26
Fig 26: Occlusal contact check

At one month follow up, direct and indirect restorations were functionally and esthetically  well integrated, all treated teeth were asymptomatic and soft tissues shown signs of rapid healing just few weeks after surgery (fig. 27-28-29).

Fig 27
Fig 27: 1 month follow up
Fig 28
Fig 28: 1 month follow up – buccal view
Fig 29
Fig 29: post operative rx

Conclusion

Adhesive posterior restorations are the most common treatment in everyday clinical practice. The consistent application of standardized protocols can lead to long term clinical success even in complex situations, when a multidisciplinary approach is required.

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