Effects of Potassium Oxalate on Knoop Hardness of Etch-and-Rinse Adhesives

Abstract

Application of potassium oxalate to acid-etched dentin may interfere with the properties of adhesives that are subsequently applied to dentin. SUMMARYThe objective of this study was to determine whether the hardness of etch-and-rinse adhesives may be affected by the pretreatment of acid-etched dentin with potassium oxalate desensitizer. Unerupted human third molars were cut into crown segments by removing the occlusal enamel and roots. The pulp chamber of these crown segments was connected to a syringe barrel filled with phosphate-buffered saline so that the moisture of dentin was maintained during the bonding procedures. Three etch-and-rinse adhesives-two two-step systems (Adper Single Bond 2 [SB], One-Step [OS]) and one three-step system (Adper Scotchbond Multi-Purpose [MP])-were applied to acid-etched dentin that had been treated (experimental groups) or not (control groups) with potassium oxalate (BisBlock). The Knoop hardness (KHN) of adhesives was taken at different sites of the outer surface of the adhesive-bonded dentin. The KHN of the three tested adhesives applied to acid-etched dentin

Effect of dentin pretreatment with potassium oxalate: A 6‐year follow‐up

“…Because the inclusion of solvent and hydrophilic compounds in the two‐step conventional adhesive should theoretically result in low bond strength (Paul, Leach, Rueggeberg, & Pashley, ), this may have occurred by incomplete solvent evaporation in the SB group, which would weaken the bonding (Hashimoto et al, ). The lack of a statistically significant difference between these types of adhesive systems corroborates the findings of another study (Silva et al, ).…”

“…(Paul, Leach, Rueggeberg, & Pashley, 1999), this may have occurred by incomplete solvent evaporation in the SB group, which would weaken the bonding (Hashimoto et al, 2006). The lack of a statistically significant difference between these types of adhesive systems corroborates the findings of another study (Silva et al, 2012).…”

Four-year randomized clinical trial of oxalic acid pretreatment in restorations of non-carious cervical lesions

“…They used the microtensile method in the laboratory and showed that, despite oxalate desensitizer being shown to contribute to the reduction of resin-dentin bond degradation over time, it compromised the baseline bond strength to the teeth that received potassium oxalate after acid etching. After 2 years, they also showed that the potassium oxalate may adversely affect the baseline hardness of etch-and-rinse adhesives [34]. Therefore, in accordance with these previous studies [21,[29][30][31][32][33][34], it can speculate that crystal precipitation on the etched dentin surface impaired the adequate hybrid layer formation.…”

“…After 2 years, they also showed that the potassium oxalate may adversely affect the baseline hardness of etch-and-rinse adhesives [34]. Therefore, in accordance with these previous studies [21,[29][30][31][32][33][34], it can speculate that crystal precipitation on the etched dentin surface impaired the adequate hybrid layer formation.…”

Dureza da camada de adesivo e da camada híbrida e a sua relação com a resistência de união à dentina

“…Desde que a mensuração da dureza foi aceita como um bom indicador do grau de polimerização das resinas compostas, têm sido realizados estudos que utilizam ensaios de dureza para avaliar esta propriedade nos sistemas adesivos (Hass et al, 2011;Silva et al, 2012 (Shimada et al, 2003;Senawongse et al, 2004).…”