Table 4. Effect height of titanium (Ti)-base abutment x cement type.

Autor	Objectives	Conclusion
Silva et al (2018) 2	To evaluate the effect of different Ti-base abutment heights and cement type on traction retention in zirconia-based restorations	They concluded that although the heights of Ti-base abutments did not influence the retentivity of zirconia superstructures, resin-based cements showed significantly greater retention than glass-ionomer and temporary cements
Zahoui et al (2020) 12	Aimed to evaluate the effect of Ti-base height, type of resin cement and surface pretreatment in Y-TZP and/or Ti-base abutment on the traction retention of implant-supported crowns in Y-TZP	Ti-base abutment height influenced the tensile strength of implant-supported CAD/CAM zirconia crowns, where tall abutments had greater retention strength than short ones