Factors Affecting the Shear Bond Strength of Orthodontic Brackets to Porcelain

Abstract

The aim of this investigation was to establish a regime for orthodontic bonding to feldspathic porcelain, which ensures adequate bond strength (6-8 MPa) with minimal damage on debond and consisted of an ex vivo investigation measuring the effects of porcelain surface preparation and thermocycling on shear bond strength of orthodontic brackets. One-hundred-and-twenty feldspathic porcelain bonded crown surfaces were divided into 12 equally-sized groups to assess the effects of: (1) glaze removal, (2) application of hydrofluoric acid, phosphoric acid, or omission of acid treatment, and (3) silane priming upon the bond strength of premolar brackets bonded with Right-on (TM) composite resin adhesive. Specimens were subjected to thermocycling and then to shear debonding forces on an Instron machine. Removal of the porcelain glaze, or use of hydrofluoric acid, prior to bonding were found to be unnecessary to secure the target bond strength. Hydrofluoric acid application was associated with increased porcelain surface damage. Thermocycling caused a significant reduction in shear bond strength to porcelain (P < 0*001). The best regime for orthodontic bonding to feldspathic porcelain was to apply phosphoric acid for 60 seconds, and prime with silane prior to bonding. Usually the porcelain surfaces could be repolished. Refereed Paper

Orthodontic bonding to porcelain: A systematic review

“…Some examples of these have been reported with the use of phosphoric acid 6 or hydrofluoric acid. 7 Other studies tested the use of silane coupling 6,8 and other present discrepancies in terms of roughening of the porcelain surface or not. 8,9 With the advancement of science and technology, dental materials are being improved at a very fast pace.…”

Interferência dos diferentes glazeamentos na colagem de bráquetes ortodônticos em superfícies cerâmicas

“…Todos os 4 grupos apresentaram resultados acima da média aceitável clinicamente que é de 6 a 8 MPa [12,21,23].…”

“…Como em Ortodontia a colagem é temporária, a força de adesão deve ser alta suficiente para resistir às forças aplicadas durante o tratamento e fraca para permitir descolagem ao final do tratamento, sem danificar os dentes e as restaurações [9][10][11]. Estudos mostram que a força de adesão é influenciada pelo tipo de bráquete, preparo da porcelana e material de colagem utilizados [12][13][14].…”

Ceramic Surface Polishing Techniques After Removal of Orthodontic Adhesive

“…In spite of this, there are bonding systems for porcelain that recommend surface roughening as a starting step. 13,14 A silane-coupling agent was used prior to adhesive application on samples, which greatly increases bond strength. 15 However, had there been an alumina overglaze, which cannot be clinically distinguished, the silane would not have been effective due to the small amount of silica.…”