%0 Journal Article
%T Knoop hardness of enamel and shear bond strength of brackets bonded with composite resin with and without fluoride
%A Vedovello
%A Silvia Am¨¦lia Scudeler
%A Grigoletto
%A Marcelo
%A Vedovello Filho
%A M¨¢rio
%A Valdrighi
%A Helo¨ªsa Cristina
%A Kuramae
%A Mayury
%J Dental Press Journal of Orthodontics
%D 2012
%I Dental Press Editora
%R 10.1590/S2176-94512012000400007
%X objective: the aim of this study was to evaluate the knoop hardness of enamel, shear bond strength and failure pattern (adhesive, bracket/resin interface or mixed) after bonding and debonding brackets, using resin composite with fluoride (ortho lite cure, ortho source£¿) and without fluoride (orthobond, morelli£¿). methods: fragments (6 mm x 6 mm) of 40 bovine incisor crowns were embedded in acrylic self-polymerizing resin. the knoop hardness measurements were performed before and after bonding metal brackets. the specimens were divided into two groups, according to composite resin: with fluoride (ortho lite cure, ortho source£¿) and without fluoride (orthobond, morelli£¿). after bonding, the specimens were submitted to demineralization and remineralization cycling for 14 days. shear bond strength testing was performed in a universal test machine (emic), at 5 mm/min crosshead speed. results: there was no significant difference in shear bond strength between groups i and ii. after demineralization and remineralization procedures (de/re), the specimens bonded with ortho lite cure showed higher knoop hardness than orthobond. for both groups there was predominance of failure at bracket/resin interface. conclusion: specimens bonded with fluoride resin composite showed higher microhardness after de/re cycling than those bonded with resin composite without fluoride, although no difference in shear bond strength was found.
%K composite resins
%K orthodontic brackets
%K hardness
%K shear strength.
%U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S2176-94512012000400007&lng=en&nrm=iso&tlng=en