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cosmetic dentistry_beauty & science No. 1, 2016

luting protocol trends & applications | 07 cosmetic dentistry 1 2016 laboratory of Hildegard Hofmann (Mainz, Germany). Pressed all-ceramic IPS e.max lithium disilicate (Ivoclar Vivadent) crowns wereselectedforthiscase,sincetheyarethe first choice for this type of indication. This has been confirmed by numerous clinical studies, including the recently published German S3 Clinical Practice Guideline on ceramic restorations. The teeth were anaesthetised at the placement appointment. The crowns were removed and the bondingsurfaceswerecarefullycleanedwithultra- sound and a fluoride-free cleaning paste. Since the new Variolink Esthetic DC (Ivoclar Vivadent) had beenchosenasthelutingmaterial,thecrownswere triedinwiththecorrespondingtry-inpastes.Anim- mediate match to the adjacent and the mandibular anteriorteethwasachievedwiththeNeutralshade. No adjustments were necessary with regard to a lighter (Light) or darker (Warm) shade of the luting composite. We attributed this excellent match to the dental technician having selected the shade at the chairside. The extra expense of this step far outweighs the inconvenience of having to make numerous adjustments or new restorations be- cause of a shade mismatch. Conditioning of the crown Saliva and residue of the try-in paste were re- moved(Ivoclean,IvoclarVivadent)fromthecrowns before they were conditioned. It is advisable to fabricate a “handle” to allow the inner crown surfaces to be conditioned without having to touch the crown with the fingers. In this case, the crowns were attached to a brush holder with a light-curing provisional composite. This handle also allowed the crowns to be placed with ease during the luting procedure. As an alternative, an OptraStick(IvoclarVivadent)couldhavebeenused. Hydrofluoric acid etching of glass-based ceramics and subsequent silanisation has been an accepted conditioning method for decades. The newest studies confirm its effectiveness. It even generates a strong bond on state-of-the-art ceramic materi- als such as hybrid ceramics. An acid concentration of5percenthasbeenestablished,whichrepresents a reasonable compromise according to the latest research. The new Monobond Etch & Prime (Ivoclar Viva- dent), which was introduced at the 2015 Interna- tionalDentalShow,isaconditioningmaterialbased on ammonium polyfluoride. The product is actively scrubbed on the bonding surface (Fig. 4) for 20 sec- onds, thereby removing any contamination with saliva or silicone. After another 40 seconds (Fig. 5), theammoniumpolyfluoridereactswiththeceramic surfaceandproducesaroughetchingpattern.Even though this pattern is not as pronounced as that of conventional 20 seconds etching with 5 per cent hydrofluoric acid, the bonding results achieved in both cases are comparable. The enlarged surface created in this way helps to activate the ceramic bonding surface. The restoration is subsequently rinsed to remove the ammonium polyfluoride and its reaction prod- ucts. The reaction of the silane and the activated glass-ceramic then begins. A thin layer of chemi- cally bonded silane remains on the ceramic after its distribution with blown air. This product, therefore, combinesthestepsofhydrofluoricacidetchingand silanisation and it even appears to render cleaning with Ivoclean superfluous. The currently available in vitro data justifies using this new product with due care to replace the hydrofluoric acid etching and silanising method. Even though it has not been shown to improve the bonding values in relation to the established references, no negative effects on the adhesive bond have been found to date either. Moreover,sincetheadhesivebondtoglass-ceramics is considered to be the most unproblematic inter- faceinthebondingprocessofindirectrestorations, no clinical irregularities are to be expected. Fig. 7: Conditioning of the prepared teeth for the adhesive cementation of the restorations under cotton roll isolation. Retraction cords were placed in the sulcus to prevent any contamination with sulcular fluids. Fig. 8: Incisal view of the prepared teeth. Fig. 9: Application of Adhese Universal adhesive with the pen applicator. Fig. 10: Light polymerisation of the adhesive after careful distribution with blown air. Fig. 11: The polymerised adhesive layer on teeth #11 and 21. Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 dentistry 12016

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