Comparative evaluation of retention of nickel-chromium crown by addition of one and two horizontal grooves on the internal surface of crown: an in vitro study

Statement of Problem. The best treatment for a dislodged crown is not clear.

Purpose. This study was designed to evaluate the increase in the retention form of the fixed prosthesis after placement of one and two horizontal grooves on the internal surface of the crown.

Materials and Method: 90 Freshly extracted sound, non-carious, non-restored human maxillary first premolar teeth were used and standard tooth preparation was done. Nickel Chromium crowns were fabricated, one and two horizontal circumferential grooves were placed on the internal surface of crown. All specimens were cemented with Resin modified glass ionomer cement and then subjected to a retention testing on universal testing machine until they were dislodged. The data was subjected to one way ANOVA test followed by Least Significant Difference (LSD) post hoc test.

Results: The results of the study showed that the mean retention value of Nickel Chromium crowns with two horizontal grooves was highest amongst all the three groups. Whereas the crowns luted with Resin modified glass ionomer cement with unaltered crowns showed the least mean retentive value. This clearly inferred that mean retention value of Nickel Chromium crowns with one and two horizontal grooves on the internal surface of crown was found out to be higher than that of unaltered crown. (p<0.05)

Conclusion: The retention of Nickel Chromium crowns significantly increased when one and two horizontal grooves were placed on the internal surface of crown luted with resin modified glass ionomer cement. There was no statistically significant difference between the mean retention value of crown with one horizontal groove and two horizontal grooves. The incorporation of horizontal groove on the internal surface of complete cast crown was found to be a satisfactory method to improve the retention.