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

Abstract

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 (ZrO(2) ) 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 ± 0.37-1.99 ± 0.40 mm and 0.72 ± 0.18-1.12 ± 0.60 mm) and ZrO(2) (1.90 ± 0.28-2.67 ± 0.67 mm and 0.22 ± 0.10-2.15 ± 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 ZrO(2) abutments.