Influence of Four Different Abutment Materials and the Adhesive Joint of Two-Piece Abutments on Cervical Implant Bone and Soft Tissue

Purpose: The main aim of this study was to evaluate the influence of four different abutment materials and the adhesive joint of two-piece abutments on the cervical implant bone and soft tissue. Materials and Methods: Sixty-four titanium implants (Camlog Conelog; 4.3 x 9 mm) were placed bone level into the edentulous arches of four minipigs. Four different types of abutments were placed at implant exposure: zirconium dioxide, lithium disilicate, and titanium bonded to a titanium luting base with resin cement; one-piece titanium abutments served as the control. The animals were sacrificed 6 months after implant exposure, and the bone-to-implant contact (BIC) area, sulcus depth, the length of the junctional epithelium and the connective tissue, the biologic width, and first cervical BIC-implant shoulder distance were measured using histomorphometry and light and fluorescence microscopy. Results: Overall, 14 implants were lost (22%). At exposure, the implant shoulder-bone distance was 0.6 +/- 0.7 mm. Six months later, the bone loss was 2.1 +/- 1.2 mm measured histomorphometrically. There was a significant difference between the two measurements (P < .0001). No significant influence could be found between any of the abutment materials with regard to bone loss or soft tissue anatomy (P > .05), with the exception of zirconium dioxide and one-piece titanium abutments when measuring the length of the junctional epithelium (P <= .01). The maxilla provided significantly more soft tissue and less bone loss compared with the mandible (P <= .02). Conclusion: All tested abutment materials and techniques seem to be comparable with regard to soft tissue properties and the cervical bone level.