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

• Published in: Microscopy research and technique Vol. 80; no. 8; pp. 870 - 877
• Main Authors: Celerino de Moraes Porto, Isabel Cristina, de Sousa Gomes Costa, Joatan Lucas, Nascimento da Silva Lopes, Marcio Rafael, Duarte de Freitas, Johnnatan, Lins Macêdo de Oliveira, Isabelle, Queiroz de Melo Monteiro, Gabriela, Japiassú Resende Montes, Marcos Antônio
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-08-2017
• Subjects: Adhesion tests; Adhesive bonding; Adhesive strength; Bond strength; Bonding strength; Dental Bonding; Dental Stress Analysis; Dentin; Dentin - drug effects; dentin bonding agents; dentin hybridization; Dentin-Bonding Agents - pharmacology; dentistry; Distilled water; Durability; Etching; Follow-Up Studies; Humans; Hybridization; operative; Oxalic acid; Oxalic Acid - pharmacology; Phosphoric acid; Potassium; Premolars; Pretreatment; Scanning electron microscopy; Statistical analysis; Storage; Teeth; tensile strength; Variance analysis; dentin bonding agents; tensile strength; dentin hybridization; dentistry; operative
• ISSN: 1059-910X; 1097-0029
• DOI: 10.1002/jemt.22876

Oxalate‐based products are effective against dentine sensitivity and have been studied as an option to improve long‐term adhesive bonding strength. Our aim was to evaluate the effect of potassium oxalate on the microtensile bond strength (µTBS) of the dentin/resin interface after 24 h, 1, and 6 years. Dentin on the occlusal surface of 16 human premolars was exposed and etched with 35% phosphoric acid. The teeth were divided into four groups. Two groups received 3% monohydrated potassium oxalate and the following adhesive systems and composites: Adper Scotchbond Multipurpose + FiltekZ350 (3M/ESPE) and Prime & Bond NT + Esthet‐X (Dentsply). Two control groups did not receive potassium oxalate. Teeth were cut into sticks and kept in distilled water at 37°C for 24 h, 1, and 6 years. The sticks underwent µTBS testing after storage. ANOVA, Tukey's post hoc test, and paired t test were used to compare storage times (α = 0.05). The fracture mode of the specimens was classified under a stereomicroscope (40×). Morphology of the hybrid layer and the fracture pattern were observed with scanning electronic microscopy (SEM). Mean µTBS was high at 24 h and decreased after 1 and 6 years. After 6 years, the mean µTBS values were similar with no statistically significant difference between the groups (p = .121). SEM images showed proper dentin hybridization. Dentin pretreatment with potassium oxalate did not affect hybrid layer formation, but bond strength decreased over time after 24 h. Therefore, the clinical use of potassium oxalate to increase dentin bond durability is not indicated.
Dentin hybridization was not affected by potassium oxalate pretreatment and the immediate µTBS improved when an etch‐and‐rinse three‐step adhesive was used. Potassium oxalate is not indicated to increase the long‐term dentin bond strength.