Influence of the position of the antrostomy in sinus floor elevation on the healing of mini-implants: a randomized clinical trial

Aim: To evaluate histologically the healing of mini-implants installed after sinus floor elevation using a lateral approach and placing the antrostomy at different level from the sinus floor. Material and methods: Sinus floor elevation using a lateral approach was performed in 24 healthy volunteers. The antrostomy was randomly placed either close to the base of the sinus floor (group base) or at about 3–4 mm cranially to it (group standard). After 6 months of healing, mini-implants were installed within the grafted region, through the alveolar crest. Three months later, biopsies were collected. Results: Sixteen biopsies from 16 patients were available for histological analyses. The new bone reached fractions of 40.9 ± 11.9% and 48.5 ± 20.1% at the base and standard groups, respectively (p = 0.208). Xenograft particles were found in contact with the implant surface at percentages of 12.1 ± 11.0% in the base group, and 15.9 ± 23.7% in the standard group (p = 0.674). Conclusions: Based on the present study, the choice of one or the other position of antrostomy did not influence significantly the outcome and, therefore, should be left to the preference of the surgeon.