Evaluation of the Sealing Capability of the Internal Conical Connections of Implants with Titanium and Zirconia Abutments.

Abstract

The purpose of this in vitro investigation was to evaluate the sealing capability of the conical implant-abutment interfaces under different abutment screw torque values using titanium and zirconia abutments with Morse taper designs. A total of 42 dental implants (n = 21 for titanium abutments and n = 21 for zirconia abutments) were inoculated internally with three bacteria. These assemblies were divided into four test groups (n = 10) based on screw fixation torques of 35 or 20 Ncm and placed in sterile broth; the remaining abutments were used as positive controls and torqued to 10 Ncm. Microleakage was quantified by enumerating the bacteria from the colony-forming units. An analysis of variance for the estimates of bacteria enumerated and microgaps was used with a post hoc analysis as indicated. A p-value of 0.05 was used as the level of significance. There was no statistically significant difference in microleakage among the four test groups; there were no significant effects of screw torque or abutment type on the bacteria enumerated. There was a significantly smaller mean microgap with the zirconia abutments. The results of this study indicated no statistically significant difference in the sealing capabilities between titanium and zirconia abutments, having internal conical connections, after increasing the abutment screw torque. It is important for clinicians to follow the guidelines suggested by the implant companies to avoid biomechanical complications over time.