Dental implant treatments have improved in both convenience and predictability with refinements in implant bodies and treatment procedures as compared to about 50 years ago when clinical applications were started. Currently, an implant body surface is treated with “rough processing” by sandblasting and acid etching for the purposes of obtaining more reliable osseointegration and shortening treatment period. Despite previous reports about the healing period when implant bodies treated in this the procedure, a common consensus has yet to be obtained.

With implant treatment, the healing period refers to the period until an inserted implant body acquires osseointegration and can be loaded with occlusal force. In order to shave off the healing period, various method in which occlusal force was immediately or early loaded on the inserted implant body have been reported. However, theories on the therapeutic effect of immediate loading or early loading of implant treatment were not unified. “Quantity and quality of bone in treatment area,” “primary stability after implant insertion,” and “intraosseous stability during the healing period” are regional factors related to the acquisition and maintenance of osseointegration.

Usually, bone quantity and bone quality are evaluated by morphometry of computed tomography (CT) images and analysis of voxel values, and primary stability is evaluated as insertion torque (IT). Intraosseous stability of the implant during the healing period is estimated from X-ray images, the Periotest, or a resonance frequency analysis device. The estimation procedure with a non-contact-type resonance frequency analysis device has been recognized as a non-invasive and reproducible procedure.

Intraosseous stability of an implant that is measured with a non-contact-type resonance frequency analysis device is evaluated as ISQ value. Insertion torque (IT) value and ISQ value are important indicators of implant treatment. However, the relationship between IT and ISQ is unclear. Some articles have reported positive correlations between IT and ISQ, but others have found no correlation.

The purpose of this study is to evaluate the relationship between IT and ISQ at implant treatment using the current rough surfaced implant. We evaluated the implant treatment sites with implant stability quotient (ISQ) values, IT values, and voxel values. We assumed that there is relevance between the insertion torque value and the ISQ value.