This study proposes a method for measuring the volumetric change of alveolar bone after dental implant surgery using computed tomography (CT). A total of 40 implants in 20 patients (15 males and 5 females) were selected. The types of implants used were group 1: 24 CMI IS-II Active implants (Neobiotech Co., Seoul, Republic of Korea) and group 2: 16 SLActive Bone Level implants (Institut Straumann AG, Basel, Switzerland). The OnDemand3D software (CyberMed, Seoul, Korea) was used for analysis. The volumetric change of the alveolar bone around an implant fixture is measured as follows: (1) Establish two cylinders: the main cylinder with the implant axis as the central axis (radius of implant + 3 mm) and the error correction cylinder (radius of implant + 1 mm). (2) The height of the cylinder extended from the top of the fixture to a 3 mm coronal portion. (3) Calculate the volumetric change of the alveolar bone (Vd) by subtracting the volume of the error correction cylinder from the main cylinder between CT images taken immediately after the implant placement and 12 months later. After a one-year installation, the volumetric change of alveolar bone, ΔV (cc) had increased in both groups (group 1: -0.011 ± 0.015 cc, group 2: -0.012 ± 0.017 cc) with statistical significance (p < 0.05), and the difference between the groups was not statistically significant (p > 0.05). This three-dimensional assessment method would be a useful clinical reference for the assessment of marginal bone change after implant surgery.
Keywords: alveolar bone; bone resorption; computed tomography; dental implant; volumetric change.