[Cone-beam CT evaluation of alveolar ridge modification subject to immediate implant with immediate loading and delayed loading].

Objective: To assess and compare the radiographic outcomes of immediate implant placement with two different loading timing. Methods: The involved cases were collected from Department of Implantology, Peking University School and Hospital of Stomatology. Patients recieved immediate implant placement during 2010 Aug to 2012 Dec. The cases admitted delayed restoration program were assigned to Group Ⅰ(18 patients with 21 implants), the cases admitted immediate restoration program were assigned to Group Ⅱ (16 patients with 22 implants). Cone-beam CT(CBCT) was taken on the day after surgery and 6 months later. The thickness of the alveolar and the vertical alteration of marginal bone level were measured using the computer software subject to the CBCT. Wound closure was performed by single sutures in Group Ⅰ. Provisional crown was delivered on the same day of implant insertion or the day after for Group Ⅱ. Comparisons between baseline data and data from 6-month follow-up in both groups were conducted using paired t test(α=0.05). Results: The success rates of two groups were both 100%. The thickness got alteration after 6 months. The largest alteration position was at the 6 mm apical to the implant platform in Group Ⅰ, which was (-0.75±1.31) mm. In Group Ⅱ for each platform got similar alterations as -0.3 mm. There was no significant differences. Vertical alteration in two Groups showed significant difference, with (-0.73±1.88) mm(Group Ⅰ) and (0.39±1.37) mm(Group Ⅱ) respectively. Conclusions: Immediate restoration of dental implants which are placed in fresh extraction sockets has more advantages than delayed restoration protocol, for it shortens the course of treatment and preserves the alveolar bone.