Effect of Diameter and Surface Treatments on the Retentivity of New Esthetic Posts

Abstract

Aims and objectives: To determine and compare the retention of different esthetic post systems within the root canal, i.e., zirconium dioxide ceramic post (Zr post) (Cosmopost Ivoclar Vivadent) and glass fiber-reinforced composite post (FRC post) (Twin Luscent Anchor, Dentatus, USA), and the effect of increase in diameter and different surface treatments on the retentivity of these posts. Materials and methods: A total number of 24 prefabricated endodontic posts, including 18 Zr post and six glass FRC post, were used for the study. Two diameters of Zr post, i.e., 1.4 and 1.7 mm, and two diameters of FRC post, 1.3 and 1.6 mm, were used. The Zr posts were divided into three main groups and subjected to three different surface treatments. The first group (group I) served as the control group and was given no surface treatment; instead, it was used as obtained from the manufacturer. The second group (group II) was given a surface treatment of airborne particle abrasion using 110 µm alumina particles. The third group (group III) was ground evenly with a coarse grit diamond bur mounted on a high-speed handpiece. The fourth group (group IV) constituted the FRC post and this group of posts was not given any surface treatment. Thus, the total sample size was fixed as 24 with 6 each to groups I, II, III, and IV. In each of these four groups, three posts each will be with 1.4 and 1.7 mm diameter, respectively. These samples were tested for retentivity, in an Instron universal testing machine. Results: One-way analysis of variance (ANOVA), small sample Student's t-test, and Pearson correlation coefficient were the statistical tools employed to analyze the observations. The glass FRC post group IV were reported to have the greatest retentivity, followed by group II. When airborne particle abrasion with 110 µm alumina on the Zr posts significantly improved its retention, and were related in a linear fashion, the surface roughening with coarse diamond bur on Zr post failed to do so. Both groups I and III did not show any increase in retentivity with an increase in the diameter. Group IV showed an increase in retentivity when the diameter of the posts was increased. Conclusion: Clinical implications of the study are that in highly demanding situations of esthetics and fracture, the zirconium dioxide ceramic post after airborne particle abrasion with 110 µm alumina is a promising restoration, provided the individual is not a bruxer or engaged in sports where there is a risk of tooth fracture. Even though zirconia post showed better fracture resistance than glass fiber-reinforced posts, the cost factor, retention, and its free availability make the glass FRC posts a promising endodontic restoration for badly damaged teeth.