The effect of bone condensation and crestal preparation on the bone response to implants designed for immediate loading: a histomorphometric study in dogs

PURPOSE: The aim of this study was to evaluate the influence of bone condensation and crestal preparation on the bone response of implants designed to promote osseocompression. MATERIALS AND METHODS: In the first phase, the mandibular premolars of 6 dogs were extracted bilaterally. After 8 weeks, each dog received 8 Xive implants (4 per hemimandible). One hemimandible was randomly assigned to the experimental group and the other to the control group. The implant site was prepared using conventional standard drills. Prior to implant placement the crestal drill was used in the experimental group but not in the control group. After 12 weeks, the animals were sedated and sacrificed. The hemimandibles were removed and prepared for histomorphometric analysis of bone-implant contact (BIC) and bone density of areas adjacent to and further from the implant surface. RESULTS: The mean +/- SD percentages of BIC attained were 71.1% +/- 11.8% and 45.1% +/- 16.1% for the experimental and control groups, respectively. The bone density analysis revealed that in the control group, percentage BIC was a mean of 55.6% +/- 11.3% adjacent to the implant and 50.7% +/- 17.9% distant from the implant. In the experimental group, percentage BIC was a mean of 71.1% +/- 8.6% adjacent to the implant and 55.6 +/- 11.3 distant from the implant. The difference between the experimental and control groups was statistically significant for both parameters, BIC and bone density, in the adjacent areas (P < .0001). CONCLUSION: Crestal preparation is of fundamental importance for this implant system, since it led to better bone response, represented by the improved BIC and bone density.