The Effect of the Pre-treatment by Hydrofluoric and Nitric acid in combined and sandblasting on the retentive force of monolithic zirconia with different yttria content

Background: Zirconia is chemically stable biocompatible material used in dentistry. Current study aimed to evaluate the effect of yttria content (5Y, 7Y & 9Y) in combination with (Hydrofluoric and Nitric Acid) and silica sandblasting on the surface structure of crown to achieve mechanical retention. Methodology: From April 2021 to November 2021 study was conducted on 54 maxillary premolars, and zirconia crowns with planned and constructed proximal extensions. Based on yttria content samples were divided in 3 groups (n=16) ceramics Copran Zri (5Y), Copra Supreme (7Y) and Copra Smile (9Y). Each group is subdivided in to three pretreatment subgroups (n=6), followed by specimen characterization via scanning electron microscopy (SEM). Targeted zirconia crown pre-treated before cementing to the associated tooth. The test of crown retention was recorded in Newtons and performed to displace the crown. The mechanical strength (MPa) was determined. Result: In Yttria concentration group the retentive strength of various zirconia crowns was found to be significant p<0.05. The Post Hoc test revealed that group 1 having the greatest mean retention strength value (5YS1). There is significant difference (p<0.0001) in retention strength and surface pretreatment observed among group 3 and 2. Conclusions: With the combination of air abrasion and hot acids, the 5Y group demonstrated the greatest retentive force. The study discovered an inverse relationship between the quantity of Yttria content and the retentive force, whereas pre-treatment with a hot acid air abrasion increased the retention of zirconia crown.