Impact of abutment material and dis-/re-connection on soft and hard tissue changes at implants with platform-switching

Objectives To assess the impact of abutment material and dis-/re-connection on soft and hard tissue changes at implants with platform-switching. Material & Methods Titanium implants (n = 12), placed epicrestally in the upper jaws of three dogs, were connected with titanium (Ti) and zirconium dioxide (ZrO2) abutments (horizontal mismatch of 0.4 mm) and randomly allocated in a split-mouth design either to repeated (2x) dis-/re-connection at 4 and 6 weeks (test), respectively, or left undisturbed (control). At 8 weeks, histomorphometrical measurements were made between the mucosal margin (PM), implant shoulder (IS) and the apical extension of the long junctional epithelium (aJE),-the most coronal level of bone in contact with the implant (CBI). Results Repeated abutment manipulation was associated with increased mean PM-aJE and IS-CBI values at both Ti (1.82 +/- 0.371.99 +/- 0.40 mm and 0.72 +/- 0.181.12 +/- 0.60 mm) and ZrO2 (1.90 +/- 0.282.67 +/- 0.67 mm and 0.22 +/- 0.102.15 +/- 0.77 mm) abutments at 8 weeks. These vertical dimensions were comparable at both vestibular and oral aspects. Between group comparisons, however, failed to reveal a significant difference between test and control sites. Conclusions Repeated manipulation may be associated with dimensional changes of peri-implant soft and hard tissues formed at both non-matching Ti and ZrO2 abutments.