31 Cienc Odontol Bras 2007 jul./set.; 10 (3): 31-37 Marginal leakage in permanent teeth after dentin treatment with air abrasion and adhesive systems Infiltração marginal em dentes permanentes após tratamento dentinário com abrasão a ar e sistemas adesivos Angela Cristina Cilense ZUANON Assistant Professor of Pediatric Dentistry – Araraquara Dental School – UNESP – São Paulo State University – Araraquara – SP – Brazil Ticiana Sidorenko de Oliveira CAPOTE Substitute Professor of Human Anatomy – Araraquara Dental School – UNESP – São Paulo State University – Araraquara – SP – Brazil ABSTRACT Due to doubts related to the application and association of techniques for appropriate adhesion, as the air abrasion system and last generation adhesive systems, the objective of this study was to evaluate the marginal leakage in Class V composite restorations in permanent teeth prepared with rotating instruments and then submitted to air abrasion and adhesive systems. Cavities were prepared with burs in high speed in facial and lingual surfaces of 25 human third molars. The specimens were divided into 5 groups of 10 preparations each: G1 (air abrasion and Scotchbond Multi Purpose), G2 (phosphoric acid and Scotchbond MP), G3 (Clearfil SE Bond self-etching system), G4 (air abrasion, phosphoric acid and Scotchbond MP) G5 (air abrasion and Clearfil SE Bond). All groups were restored with Z100 composite resin. The teeth were subjected to thermal cycling and immerged in 50% silver nitrate solution. After sectioning, the specimens were analyzed with a stereomicroscope for assessment of microleakage according to the degree of dye penetration. The Kruskal-Wallis test followed by Dunn Multiple Comparison test were performed in order to evaluate the differences among the experimental groups. Air abrasion groups demonstrated the greatest leakage. Scotchbond MP with phospho- ric acid produced the least leakage, with greater leakage in gingival margins than occlusal margins in all experimental groups. It was concluded that dentin treatment with air abrasion should not be used in permanent teeth to reduce the marginal leakage. UNITERMS Dental leakage; dental air abrasion; dentin-bonding agents. INTRODUCTION The air abrasion system uses a high-speed stream of purified aluminum oxide particles propelled by air pressure. In 1945, Black 2 reported on the airbrasive technique for nonmechanical cavity preparation in response to the need to increase patient confort by reducing pressure, heat, vibration, and noise during the mechanical preparation of teeth with rotating bur. 8,26 Good results have been gotten by combining air abrasion with acid etching in some studies. 7,10,26 Even so, other studies demonstrated that air abrasion system does not substitute acid etching and the association of these methods is necessary to obtain adequate adhesion to the substrate. 3,9,20,25,29 The conventional adhesive systems, which use the total-etch technique, generally indicate the phosphoric acid fosfórico as acid conditioning agent. The self-etching materials eliminated the acid condicioning step by use of a primer containing an acid monomer. The smear layer components are probably incorporated within the bonding layers, since the dissolved matter is not rinsed away. 19