Evaluation of gold-machined UCLA-type abutments and CAD/CAM titanium abutments with hexagonal external connection and with internal connection.

PURPOSE The purpose of this study was to assess the precision at the implant interface of gold-machined UCLA-type abutments and computer-assisted design and manufacture (CAD/CAM) titanium abutments with both external-hexagonal connection and internal-hexagonal connection. MATERIALS AND METHODS Fifteen gold-machined UCLA-type abutments with external-hexagonal connection, 15 gold-machined UCLA-type abutments with internal-hexagonal connection, 15 CAD/CAM titanium abutments with external-hexagonal connection, and 15 CAD/CAM titanium abutments with internal-hexagonal connection were produced. The rotational freedom of all the abutments was assessed to detect the precision of fit of each abutment on the top of the implant platform. Measurements of rotational freedom were compared among groups. The quantitative differences among groups were assessed using 1-way analysis of variance (alpha = .05). RESULTS Significant differences relative to rotational freedom were not found among the 4 groups (P > .19). CONCLUSION Both types of abutments (gold-machined UCLA-type and CAD/CAM titanium) consistently showed 1 degree of rotational freedom between the implant and abutment in both cases of external-hexagonal connection and internal-hexagonal connection.