Bone mineral density as a criterion for primary implant stability: A retrospective CBCT analysis

The purpose of this study was to examine the relationship between the local bone density derived from a cone-beam computed tomography (CBCT) scan from different sites in the maxilla and mandible and the insertion torque values, for the success of oral implants.

A total of 73 patients who reported to our unit, with missing teeth and a desire for replacement with dental implants, were included in this study. A total of 118 implants were placed from 2008 to 2011. The number of male and female patients included in the study was 43 and 30, respectively. The mean age of the patients was 43.2 years. NobelReplace Select Tapered Implant system was used for all patients.

The mean bone density of all 118 implants was 620 ± 251 Hounsfield units (HU). The mean bone density and insertion torque values of the six failed implants were 459 ± 131 HU and 28 ± 5 Ncm, respectively. The mean bone density and insertion torque values of the 112 successful implants were 678 ± 217 HU and 36 ± 2 Ncm, respectively. A significant strong positive correlation was observed between bone density and torque at all sites.

CBCT is a useful tool to determine the bone density of the concerned areas before implant placement. The valuable information derived from the CBCT about bone quality may help clinicians to avoid the placement of implants into the very poorest qualities of bone, where failure is more likely.