Correlation of radiographic fractal analysis with implant insertion torque in a rabbit trabecular bone model.

B quality is a main factor influencing the success of dental implant treatment.1 Clinical studies have shown that bone of soft quality significantly increases the implant failure rate.2,3 The poor engagement offered for implant threads and consequent difficulty in obtaining satisfactory stability are traditionally offered as explanations for the higher failure rates in soft bone.3 In agreement with the aforementioned clinical outcomes, a histomorphometric assessment of the structural quality of trabecular bone of edentulous maxillae showed that the softer bone in posterior areas had significantly lower trabecular bone volume, number, and connectivity as compared to denser bone in anterior maxillae.4 However, because of the very wide variations in the bone structure of both jaws, soft bone may be present in many areas.4,5 With modified surgical techniques and extended healing periods before loading, satisfactory implant outcomes are achievable in soft bone.6 Evaluations of bone mechanical qualities are therefore crucial to choose a final diameter of the implant site and the length of the healing period that are appropriate for a patient’s bone type.6 Bone mechanical properties are dependent on bone quality and bone density.7 Bone quality encompasses trabecular and cortical bone architecture, bone mineralization, turnover, and microdamage,7 while bone density is defined by the grams of mineral content per area or volume of bone.7 1 Lecturer, Department of Oral Surgery, University of Siena, Italy. 2 Professor and Chair, Department of Dental Materials and Fixed Prosthodontics, University of Siena, Italy. 3 Associate Professor and Chair, Department of Oral Surgery, University of Siena, Italy.