Mechanism for Erosion of Glass-ionomer Cements in an Acidic Buffer Solution

Abstract

In order to clarify the mechanism for erosion of glass-ionomer cements, we immersed two commercial luting cements in an acidic buffer solution under various conditions. The amounts of F, Al, Si, and Ca eluted from the cement were (1) in proportion to the square root of immersion time, (2) unrelated to shape or volume of the sample, (3) dependent on its surface area, and (4) not affected by shaking of the solution. It was concluded that the dissolution was controlled by the diffusion of those species in the cement matrix, which was influenced by the structure of the matrix and the concentration of H+ ion at the cement surface. The unreacted glass particles near the cement surface were dissolved by the long immersion, and many pores were left in the surface region.

Gentamicin Sulphate Release from a Modified Commercial Acrylic Surgical Radiopaque Bone Cement. I. Influence of the Gentamicin Concentration on the Release Process Mechanism.

“…Some of these craters seem to be the remains of the GS beads. The same effect has been observed by Fukazawa et al 25,26) in the case of the erosion of glassionomer cements. The buffer would dissolve these GS beads gradually leaving a number of pores near the surface of the GS modified cement slabs.…”

Comparative Evaluation of Shear Bond Strength of Luting Cements to Different Core Buildup Materials in Lactic Acid Buffer Solution

“…It is believed by some investigators that the rate of disintegration in the dilute organic acids common to the oral cavity could provide data which are more meaningful clinically than in distilled water or artificial saliva [19]. Also, when used for luting, the cement around the margins of restorations is in stagnation area and therefore subjected to pH lower than 7 through the action of bacterial plaque or sugars to produce, in particular, lactic acid [20]. According to the study done by Sandra Hewlett et al, [1] the shear bond strength of the core materials to various luting agents was significantly reduced after immersion in 0.01 M Lactic acid as compared to those stored in 100% humidity.…”

“…This was done to simulate the in vivo conditions. The lactic acid of pH 4 was used based on the previous invitro studies [9,[20][21][22][23][24][25][26][27].…”

The erosion kinetics of conventional and resin-modified glass-ionomer luting cements in acidic buffer solutions

“…Glass-ionomer cements have desirable properties to prevent recurrent caries by eluting ions for a long period of time 12,13) . Unfortunately, there is still some confusion in the literature about solubility, disintegration and erosion characteristics of dental cements when clinical results 14,15) are compared with those of the laboratory ones 5,6,9,12,[16][17][18][19] . Furthermore, the results of in vitro studies also show variations for these cements 9,12) .…”

“…This is partially because the erosion behaviour of such cements was studied using different media. While some investigators studied the erosion behaviour of glass-ionomer cements in distilled water 6,16,20,21) , others used organic acids 3,18,22,23) , organic acid buffer solutions 7,9,12,17,19) or preferred to use the actual oral environment 4,14,15) . The organic acids such as lactic acid and acetic acid that changes the acidity of the oral environment are produced by the microorganisms as a result of carbohydrate intake to the mouth 22) .…”