Relationships between bone density values from cone beam computed tomography, maximum insertion torque, and resonance frequency analysis at implant placement: a pilot study.

PURPOSE: The aim of the present study was to determine bone density in designated implant sites using cone beam computed tomography (CBCT) and to evaluate possible correlations between age, gender, insertion torque measurements, and resonance frequency analysis (RFA) values.
MATERIALS AND METHODS: Completely and partially edentulous patients were treated with implants between 2007 and 2008 and evaluated retrospectively. The preoperative examination included a panoramic radiograph, CBCT, diagnostic casts, and a clinical examination of the jaws. With the CBCT scans, bone densities were recorded in Hounsfield units (HU). Insertion torque values and implant stability measurements (via RFA) were also noted.
RESULTS: Mean bone density and insertion torque values were 623 ± 209 HU and 42.4 ± 4 Ncm, respectively, for the 82 implants placed. Mean primary stability (implant stability quotient) was 62.4 ± 8. The differences in mean bone density at implant sites in the mandible (717 ± 204 HU) and the maxilla (490 ± 128 HU) were statistically significant for all patients (P < .05). There was a statistically significant relationship between bone density values and insertion torque measurements for implant sites in the anterior mandible (r = 0.562, P < .05), as well as between bone density and RFA values for men (r = 0.412, P < .05).
CONCLUSIONS: Bone density measurements using preoperative CBCT may be helpful as an objective diagnostic tool. These values, in conjunction with RFA values and insertion torque measurements, can provide the implant surgeon with an objective assessment of bone quality and may be especially useful where poor-quality bone is suspected.