Effect of implant abutment material and type of restoration on retentionof cement-retained implant supported-prosthesis

Abstract

The purpose of this study was to assess andcompare the retentive nature of the common abutment materials used clinically withtwo different types of ceramic restorations using provisional cement. Twenty implant analogswereembedded in 20 blocks of acrylic resin.10 implant analogs received a straight Titanium abutment (ready made), and 10 implant analogswere received a straight implant Titanium base attached and torqued to 35 Ncm. Then the Ti-base and the ready-made Titanium abutments were scanned. Using the CAD/CAM software ( exocad) the custom-made abutment was designed, verified with PMMA sample, constructed and cemented on the Ti-bases by a permanent resin cement.10 zirconia and 10 e.max CAD crownswere constructed. The cement used wasTempbond NE cement. Each sample was subjected to a pull-out test using an Nexygen from Lloyd Instruments universal testing machine at a crosshead speed of 5.0 mm/min. Loads required to remove the crowns were recorded, and mean values for each group determined. Data were statistically analyzed using IBM SPSS Statistics Version 20 for Windows. T-test and Paired Samples. The mean values(±SD)ofloads at failure (n = 5) for each group were as follows in Newton (N): E.max-Titanium group(A)195.51 (±22.16), Zirconia-Titanium group(B) 94.225 (±15.106), E.max-Zirconia group(C)150.9 (±13.579), Zirconia-Zirconia group(D)110.84 (±22.596) Groups A&C were statisticallysignificant.

Conclusion: Within the limitations of this in vitro study; - There was no difference between titanium and zirconia abutments in retention. - The e.max crowns showed better retention than zirconia crowns with both titanium and zirconia abutments. The best combination was using e.max crown with titanium abutment. While, the worst combination was using zirconia crown with titanium abutment. - Using the zirconia crown with the zirconia abutment is considered to be an adequate combination.