CATEGORY AUSTRALASIAN DENTIST77 CLINICAL of the nano-hybrid CAD/CAM composite Grandio blocs, according to the VOCO instructions for use, its surface did not need to be further conditioned with any etching agent. It was su cient to sandblast it with Al2O3 (Rocatec, 50 µm, pressure of 2 bar, 3M), condition it with the silane coupling agent Ceramic Bond (VOCO) for 60 seconds, and then dry it using a gentle air stream for 5 seconds (not shown). Conditioning of the build-up and the hard tissue: Also the composite buildup surface on tooth 16 was sandblasted (Rocatec, 50 µm, pressure of 2 bar, 3M) to increase its retention potential and then rinsed with water. e e ect of the te on tape isolation used to prevent damage to the adjacent teeth was visible (Fig. 11a). With the self-etching dual-curing universal adhesive Futurabond U (VOCO) (Fig. 11c), a preliminary etching of the tooth hard tissue using phosphoric acid gel is merely optional. In fact, Futurabond U alone achieves high levels of adhesive strength on enamel and dentine, so that prior etching of the hard tissue – and possibly of composite surfaces – may be carried out as in this case (Fig. 11b), though it is not required. Only enamel which is unprepared must be etched and rinsed at the beginning of the bonding process. e generated microretentions help the dual-curing cement system Bi x QM (VOCO) to properly lute with the hard tissue (Fig. 12). At the beginning of the chemical curing time of 3 minutes, 30 s were initially waited for Bi x QM to set in the marginal area (Fig. 12a). is 30 second pause is intended to prevent shrinkage and gap formation, which can occur if the adhesive material is levelled too early. Only then a foam pellet (Pele Tim, VOCO) held by tweezers was used to level the luting material in the marginal zone so that all soft excesses were removed. (Fig. 12b). After careful cleaning (not shown), light-curing was carried out from vestibular to palatal (Celalux 3, VOCO) to ensure complete polymerisation of the cement material in the marginal area. e rubber dam was removed, the occlusion was adjusted (Fig. 13) and the endo-overlay was polished (Fig. 14). Discussion e reported case presented several challenges, each of which required appropriate approaches. An incomplete longitudinal fracture can be a challenging decision because if the fracture is accidentally increased using instruments, it can result in damage to the oor of the pulp chamber, symptoms and lead to tooth loss (Gill et al., 2021). e incomplete longitudinal fracture described here could have provided a portal of entry for microorganisms or the mechanical basis for cracked-tooth syndrome. erefore, it had to be closed directly with a composite (GrandioSO, VOCO). A further di culty was achieving good absolute isolation, which is a prerequisite for deep margin elevation (Dietschi und Sprea co, 1998) with predictable longterm results (Van Meerbeek et al., 2005; Dietschi und Sprea co, 2019). Mechanical gingival retraction prepared the site for easier rubber dam placement and ensured proper moisture control on the adhesive interface. e coronal margin relocation does not negatively a ect the periodontal health status of patients, provided that the connective compartment of the supracrestal tissue attachment is not injured (Ghezzi et al., 2019). e situation at this point was consistent with a large class 1 cavity. In order to ll it without having to worry about the problems resulting from the stress-related shrinkage associated with composites, it was decided to use a bulk- ll composite. e development of state-of-the-art bonding agents and bulk- ll materials for usage inside the pulp chamber has expanded their application range and reduced technique sensitivity (Hayashi et al., 2019; Mannocci et al., Fig. 01 Initial situation: longitudinal mesiopalatal fracture. Fig. 04 Application of Futurabond U. Fig. 07 Creation of a marginal bevel (a) and finished prepared cavity from occlusal (b) and mesial (c). Fig. 02 Occlusal (a) and mesial (b) of theinitial situation. Fig. 05 Deep Margin Elevation (DME) from the occlusal (a) and mesial (b) views. Fig. 08 Virtual construction of the endo overlay (a) and Grandio blocs mounted for milling (b). Fig. 03 Absolute isolation with rubber dam (a) followed by phosphoric acid etching step (b) Fig. 06 VisCalor bulk (VOCO) enables the build-up, volume reduction of the pulp chamber and shaping in one step. Fig. 09 Milled endo-overlay with a thickness of 1 to 1.5 mm, measured using an Iwanson caliper.
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