GAP Australasian-Dentist-Mar Apr 2019

Category 48 AustrAlAsiAn Dentist H elping practitioners to work in a simpler way – without compromising aesthetic appearance, outcome success and longevity – is crucial to adhesive dentistry, according to speakers from 3M’s lunch symposium, held in spain last year as part of the FDi World Dental Congress. experts from around the world spoke to over 150 dental professionals about how smart chemistry – such as the development of products that can bond to different substrates with less complex pre- treatment required –– is leading to simpler protocols, less work steps and safer procedures. this is evident in applications such as cementation, direct restorative procedures, and adhesive techniques like selective enamel etching. Adhesive dentistry is a highly complex discipline by nature: A strong and long-lasting bond needs to be established to various restorative materials on one side and tooth substrates on the other. For example, there is not only a difference between enamel and dentine, but also between coronal and root dentin, and ceramics with a glass matrix have a completely different structure and composition than polycrystalline ceramics, composite or metal. so it comes to no surprise that the materials do not have identical pre-treatment and cementation requirements. nevertheless, it is possible today to simplify the protocols, more than 150 dental professionals attending the 3M lunch symposium at the FDi World Congress 2017 learned on thursday, August 31 in Madrid, spain. Material development in the beginning, Dr sigrid Hader, MD, PhD (3M, Germany) focused on the challenges a manufacturer has to overcome to provide materials that allow for simplified workflows. she picked out two products from the company’s portfolio – 3M™ scotchbond™ universal Adhesive and 3M™ relyX™ unicem selfAdhesive resin Cement – to illustrate how much effort is involved in the development of innovative materials. For both products, smart chemistry had to be invented to create the ability of bonding to different substrates with either no or less complex pre-treatment involved. this leads to a reduction of cases: scientific and clinical evidence confirms that very good clinical results can be obtained – provided that the user follows the manufacturer’s instructions. Simplifying cementation Dr Ana sezinando, DDs, Ms, PhD (Private Practice, Portugal) presented clinical protocols for the cementation of indirect ceramic restorations. she explained the necessity of treating ceramics with a glass matrix (e.g. feldspathic porcelain, lithium disilicate) differently than polycrystalline ceramics (e.g. zirconia). Glass-matrix ceramics always require etching with hydrofluoric acid and adhesive cementation. through the combined use of an adhesive with an adhesive resin cement, a strong bond is ensured and the stability of the ceramics increased. For maximum simplification, the use of a universal adhesive containing silane (scotchbond universal Adhesive) is recommended by the speaker, as this eliminates the need for a separate primer. regarding the tooth substrate, the preferred adhesive technique is selective enamel etching: the dentine should not be etched because the etchant would remove calcium from the tooth surface, which is needed to ensure proper interaction with the adhesive. By contrast, the enamel should be etched as a certain amount of demineralisation is required to establish a strong bond. universal adhesives are only mildly acidic so that their demineralising effect is limited. HF etching has no effect on polycrystalline ceramics. instead, the bond strength is increased by sandblasting (alumina particle size 30–50 µm, pressure < 2 bar). After thorough cleaning, restorations with a retentive designmay be placed using conventional or self-adhesive resin cement. the former is indicated with infragingival preparation margins as it is easier to remove the excess. the self-adhesive material – e.g. relyX unicem 2 cement – is preferred in all other situations. it is also the material of choice for cementation of posts in the root canal due to its ease of use and high sealing ability. Simplifying direct procedures Finally, Prof. Paulo Monteiro, DMD, Msc (isCeM, Portugal) shared his ideas of how to simplify direct restorative procedures. the goal should be to work in a less complicated way without compromising the aesthetic appearance and longevity of the outcome. Both in the posterior and anterior regions, the speaker uses scotchbond universal Adhesive in the selective enamel etch technique to lay the foundation for a safe and efficient procedure. For restorations in the posterior area, he likes to employ a high-viscosity bulk fill material. they offer strong mechanical properties and do not need a capping layer of universal composite. As they may be applied in layers of up to 4 mm, fewer steps are required than for the incremental approach. the bulk fill composite launched most recently – 3M™ Filtek™ One Bulk Fill restorative – even Simplifying success in adhesive dentistry eV nts By Christiane Stein, 3M Oral Care, seefeld, Germany Continued page 50 The three speakers after the symposium. The congress venue: IFEMA – Feria de Madrid. Participants during the 3M Lunch Symposium in Madrid.