©Operative Dentistry, 2009, 34-3, 280-287 AN Cavalcanti • RM Foxton • TF Watson MT Oliveira • M Giannini • GM Marchi Clinical RelevanceAir abrasion and the use of special functional monomers that are able to chemically bond to zirconium dioxide can improve adhesion to a highly dense zirconia ceramic. Fragments of dentin with a cylindrical edge (0.8 mm in diameter) were fixed to ceramic surfaces with the resin cements. The micro-shear bond test was carried out at a 1 mm/minute speed until failure, and the ceramic surfaces were examined after debonding. Bond strengths were analyzed through three-way ANOVA/Tukey test with a 5% significance level. Changes in topography after surface treatments were evaluated with scanning electron microscopy. Surface treatments significantly modified the topography of the Y-TZP ceramic. Air abrasion resulted in increased SUMMARY

No abstract

No abstract

Higher laser power settings (400 and 600 mJ) cause excessive material deterioration, making them unsuitable as surface treatments for zirconia surfaces. Irradiation with 200 mJ provides mild surface alterations, with intermediary features between the effects of air abrasion and higher laser intensities.

No abstract

Compared to conventional ceramic systems, Yttrium-stabilized tetragonal zirconia (Y-TZP) ceramics have some superior mechanical properties, ensuring a broad application in dentistry. The current study aimed to present relevant information about Y-TZP ceramics gathered from peer-reviewed papers. A search of the English language peer-reviewed literature was conducted using the PubMed database between 1998 and 2008. Articles that did not focus exclusively on the clinical application of Y-TZP ceramic restorations were excluded from further evaluation. Selected papers describe the chief characteristics of zirconia ceramics and important clinical features, especially those related to cementation procedures. The literature shows that, although new substances and equipment for the surface preparation of zirconia ceramics are in development, the most promising luting protocol seems to be the use of air abrasion with aluminum oxide particles (silanated or not), followed by the application of resin cements or surface primers containing special reactive monomers. However, because zirconia ceramics have only recently been developed for dental applications, there is not enough clinical evidence to support any definitive cementation protocol.

No abstract

SUMMARYThis study examined the ultrastructure of both intact and caries affected dentin-adhesive interface after artificial secondary caries formation, using scanning electron microscopy and nanoindentation testing. Half of the prepared specimens were bonded with Clearfil SE Bond (Kuraray Medical, Japan) and a resin composite (Metafil Flo, Sun Medical, Japan) for the nanoindentation test. The other specimens were stored in a buffered demineralizing solution for 90 minutes, then observed using SEM. An acid-base resistant zone (ABRZ) was observed beneath the hybrid layer, distinguished by argon-ion etching. The ABRZ of caries-affected dentin was thicker than that of normal dentin, while its nanohardess was lower than normal dentin (p<0.05). It is suggested that the monomer of Clearfil SE Bond penetrated deeper than previously reported, creating a so-called "hybrid layer." However, its physical properties depended on the condition of the dentin.