O papel da estratégia adesiva na resistência de união de restaurações indiretas a dentina com cimentos resinosos duais

Abstract

Two studies assessing the influence of cementation strategy on indirect restoration cementation to dentin, regarding immediate and long-term bond strength are presented in this composition. The first paper is an in vitro study that assess bond strength to dentin of a hybrid ceramic when cemented with different dual resin cements, under different cementation strategies. Ceramic blocks (VITA Enamic) were cemented to a flat exposed dentin surface. Dual resin cements were tested, one self-adhesive (Relyx U200 – 3M-ESPE) and one conventional (Relyx Ultimate – 3M-ESPE), through etch-and-rinse (ER) adhesive strategy or no dentin surface treatment (NT), without previous dentin phosphoric acid etching and combined with different chemical ceramic surface treatment (silane agent vs. Scotchbond Universal). Teeth were considered as experimental unity of experimental groups (n=6). The groups were divided considering cement and cementation strategy used. Stick-shaped specimens were obtained by cutting the cemented restorations. Specimens were submitted to microtensile bond strength in a universal testing machine (EMIC). Half of the specimens were testes 24h after cementation and other half were tested after 12m of distillated water storage. Results showed that Relyx Ultimate, combined with ER strategy, presented better bond strength results immediately and after aging. We concluded that conventional dual resin cement, combined with ER strategy produced better bond strength to dentin when cementing indirect restoration. The second study is a systematic review with meta-analyses that reviewed literature for in vitro studies that assessed these two classes of resin cements (conventional and self-adhesive), according to the following inclusion criteria: studies that evaluated bond strength between dentin and indirect restoration cemented with dual conventional or self-adhesive resin cements, with bond strength presented in mega Pascal (MPA) as outcome. Included studies were full-text reviewed by two independent reviewers (LLM and ACF), which applied exclusion criteria. From a total of 518 studies, 36 were screened full-text and reviewed according to exclusion criteria. 19 papers were included in systematic review and meta-analyses. A global analysis comparing conventional and self-adhesive cements, and three subgroups analyses comparing long-term bond strength performance and individually comparing immediate to long-term results of each resin cement class. Conventional resin cements, combined with adhesive system, presented an overall better adhesive performance when used to cement indirect restorations to dentin. Based on the results of both studies, dual conventional resin cements exhibited higher bonding strength to dentin when cementing indirect restorations. This cement category shows higher bond strength to dental substrate due to adhesive agent mediation. Self-adhesive cements performance is directly related to commercial brand, which must be considered when electing this resin cement class to clinical use.