Peri-implant soft tissues around implants with a modified neck surface. Part 1. Clinical and histometric outcomes: a pilot study in minipigs

Aim The goal of this study was to investigate the effect of a modified transgingival implant collar surface (acid-etched structure and hydrophilic properties) comparatively to a machined collar surface on the clinical and soft tissue integration to pure titanium implants (Ti) and titanium implants alloyed with zirconium (TiZr). Material and Methods Twenty-seven implants belonging to the following groups (9 of each group): Ti modSLA with machined collar (Ti-M), Ti modSLA with machined, acid-etched surface collar (Ti-modMA) and TiZr modSLA with machined, acid-etched surface collar (TiZr-modMA) were placed in the mandible of 6 minipigs. After 8weeks of healing, clinical measurements were taken and the sample sites were dissected and processed for histological evaluation. Results Eight weeks after implantation, the mucosa was generally located above the implant shoulder for all implant types. Histomorphometric evaluation revealed that the sulcular epithelium, junctional epithelium and the connective tissue contact were similar in the three groups. Adjusted comparisons showed that the first bone-to-implant contact was statistically more coronal for the Ti-modMA in comparison with the machined. Conclusion The soft tissue dimensions around all implant prototypes were similar and not affected by the implant surface modification.