The impact of modifying alumina air abrasion parameters on the fracture strength of a porcelain laminate restorative material

OBJECTIVES: The modification of the "fit" surface of porcelain laminate veneer restorations in order to improve adhesion prior to cementation is often indiscriminate. As a consequence, the surface flaw distribution which is implicated in the probability of failure of the restoration is likely to be dramatically modified. The purpose of the current study was to examine the impact of different air abrasion surface treatments on the bi-axial flexure strength and surface roughness of a porcelain restorative material. METHODS: Sets of 30 Vitadur-Alpha dentin porcelain discs (15 mm diameter, 0.9 mm thickness) were alumina abraded with three different grades of alumina particle (25, 50 and 110 microm), utilizing two different air stream pressures (35 and 70 psi) and two distinct angles of incidence of particle delivery (45 degrees and 90 degrees ). Mean bi-axial flexure strengths, standard deviations, the associated Weibull moduli (m) and characteristic stress were determined using bi-axial flexure (ball on ring). RESULTS: A univariate general linear analysis of means revealed a significant difference between the mean bi-axial flexure strength values of the control group and those of groups subjected to alumina particle air abrasion. Further significance (P