Effects of immediate loading with threaded hydroxyapatite-coated root-form implants on single premolar replacements: a preliminary report.

PURPOSE This prospective study evaluated the immediate loading of single, threaded, root-form implants placed in the maxillary premolar area. MATERIALS AND METHODS Ten human subjects were included in this preliminary report. In all cases, a screw-retained temporary acrylic resin crown was placed immediately after implant surgery. The definitive screw-retained metal-ceramic crown was placed 6 months later. RESULTS Standardized radiographs demonstrated 0.58, 0.73, 0.84, and 0.90 mm mean marginal bone loss at 1, 3, 6, and 12 months after implant surgery, respectively. Implant mobility was evaluated with the Periotest device. At the day of surgery, mean mobility was -3.3, while minor changes were observed thereafter: mean values of -3.77, -3.47, and -3.63 were recorded at 3, 6, and 12 months after implant surgery, respectively. Sulcus depth appeared relatively stable after the 3rd month when the implant platform was used as a reference. Recession of 0.43 mm was recorded between the 3rd and 12th month; when the depth of the peri-implant sulcus was measured from the implant platform, 0.1 mm of change was seen between the 3rd and 12th month. Probing depth measurements revealed that 3 months after implant placement, average probing depth was 3.60 mm, while at 12 months it was 3.20 mm. DISCUSSION The peri-implant soft tissue parameters (bleeding on probing, probing depth, peri-implant soft tissue level), mobility, and marginal bone level appeared to be similar to findings of previous studies regarding the conventional 2-stage loading protocol. CONCLUSION Results of the current study provided evidence that, under the condition of this investigation, single root-form implants can be immediately loaded when placed in the maxillary premolar area.