Adhesion strength of orthodontic brackets to acrylic surfaces. A systematic review on in vitro studies.

Objectives: The aim of this study was to systematically review the available literature about in vitro orthodontic bond strength tests regarding bonding brackets to acrylic teeth. Methods: A comprehensive electronic database search with no date or language limits was conducted. Relevant studies were selected based on predefined criteria: in vitro investigation on the shear/tensile bond strength of brackets evaluated and expressed in megapascals and/or considering the adhesive remnant index; and studies with a clear explanation of the bonding technique/protocol, bonding materials and type of surface acrylic material used. Results: 2044 published articles were presented by the four databases. Of the studies collected from all the databases, 28 based on their title and 14 based on their abstract, only 10 studies fulfilled the selection criteria after being examined twice by the two reviewers. Conclusion: The type of surface noticeably influenced the adhesion, and surface treatments should be performed to improve bond strength.